JP2004166498A - Electronic apparatus, charger, and charge control circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge control technology which can make efficiently chargeable a secondary battery of an electronic apparatus. <P>SOLUTION: The electronic apparatus supplies input voltage given from a power supply to a load and can charge the secondary battery with the input voltage. The apparatus is constituted so that it has a charger which supply charging electric power to the secondary battery by the input voltage from the power supply, a detector which detects the input voltage from the power supply, and a charge control circuit which control the charging electric power supplied to the secondary battery from the charger according to the detected input voltage. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an electronic device, a charging device, and a charge control circuit that can efficiently charge a secondary battery of the electronic device.

  In a portable electronic device such as a notebook personal computer, a battery is mounted as a power supply for the device. However, due to the operation cost of the device and the current capacity capable of instantaneously discharging, a battery such as Nicd, NiMH or Li + is used. Generally, a secondary battery (rechargeable battery) is mounted. In many cases, a charger is built in so that a secondary battery built into the device can be easily charged simply by connecting an AC adapter or the like to the device.

  In such a portable electronic device, a built-in secondary battery is usually used as a power source of the device. However, in a case of operation on a desk, power is supplied from an external power source such as an AC adapter. There is also an operation to make it operate.

  If the power that can be supplied from the AC adapter connected to the device is sufficiently larger than the maximum power used by the device and the maximum power required for charging the secondary battery, the operation of the device and the charging operation of the built-in secondary battery can be performed. It is possible to do it at the same time. However, if the capacity of the AC adapter is smaller than that, it is impossible to supply power to both the operation of the device and the built-in secondary battery, so either one of them must be operated according to the state of the device. It becomes. In an AC adapter actually used for an apparatus, supply power is limited due to factors such as cost and size, and generally, it is rare to perform both operations simultaneously.

  Normally, to minimize the cost and size of the AC adapter, set the capacity of the AC adapter to the larger of the maximum power required to charge the internal secondary battery and the maximum power used by the device. It is common to set. Further, in an apparatus intended to operate on a battery, it is general that the charging power to the built-in secondary battery is larger than the maximum power consumption of the apparatus. This is because, in a state where this is reversed, the operation time on the battery is shorter than the charging time on the battery, which is not practical as a device.

  Against this background, the charger built into the device has always monitored the state of the device and charged the secondary battery when the device was in the OFF state. When the power supply of the device is turned on, charging of the secondary battery is stopped, and when the power supply of the device is turned off, the charging is restarted. That is, a configuration is adopted in which charging of the secondary battery is performed when the device is in the non-operation state, and charging of the secondary battery is stopped when the device is in the operation state.

  However, in this case, when the capacity of the AC adapter has a margin, efficient charging processing cannot be executed. Therefore, recently, when the capacity of the AC adapter is somewhat larger than the maximum power used by the device, When the power supply of the device is in the ON state, the charging current value to the secondary battery is reduced to continue charging, and when the power supply of the device is in the OFF state, charging is performed at the original charging current value. It has come to be taken. That is, when the device is in a non-operation state, a large charging current is generated to charge the secondary battery, and when the device is in an operation state, a small charging current is generated to charge the secondary battery. Has come to be adopted.

  FIG. 13 illustrates this conventional configuration.

  In the figure, a secondary battery is a rechargeable battery composed of battery cells connected in series. The DC connector is a connector for receiving an external power supply when the apparatus is operated with an external power supply such as an AC adapter or when the secondary battery built in the apparatus is charged with an external power supply such as an AC adapter. . The DC / DC converter is a power supply for an apparatus for receiving power from an external power supply or a secondary battery supplied via a DC connector and generating a voltage required by the apparatus.

  The charger is a constant current source for generating power required to charge the secondary battery when power is supplied from the outside via the DC connector. The charge control unit controls the start and end of charging of the secondary battery according to the power supply from the DC connector and the operation state of the device, and controls the magnitude of the charging current generated by the charger. Mechanism.

D ₁ and D _4, due to reasons such as the AC power to the AC adapter is not supplied, when the AC adapter is in the non-operative state, reverse flow to prevent the outflow of power to the outside from the secondary battery This is a blocking protection diode. D _2, when the power from the outside is not supplied, to supply electric power from the secondary battery to the DC / DC converter, when the power from the outside is supplied via the DC connector, the voltage is two This is a protection diode for preventing application to the next battery.

The charger is a DC-DC circuit that operates by a PWM control method, and includes a switching main transistor Tr ₁ that is ON / OFF controlled, a choke coil L ₁ , a flywheel diode D _3, and a smoothing capacitor C _1. And current control resistors R ₀ , R ₁ , R ₂ , R ₃ , R _4, and a DC-DC controller for controlling the constant current control. The resistor R ₀ is a sense resistor for measuring a current value charged to the secondary battery. The voltage drop due to this current is divided by the resistor R ₁ and the resistor R ₂ and the resistor R ₃ is divided with partial de and the resistor R ₄ is input to the DC over DC controller. The resistor R ₅ is a voltage dividing resistor for controlling the sense potential of the charging current measured by the resistor R ₀ , and has a large current value generated by changing the resistance value of the resistor R ₄ connected in parallel. Will be switched.

This charger operates to generate a current value uniquely determined by the resistance values of the resistors R ₀ , R ₁ , R ₂ , R ₃ , and R ₄ , and outputs the current of the resistor R ₅ specified by the charge control unit. It operates in two current modes depending on whether it is valid or not. This constant current operation is the same as that of the switching type regulator.

In the case that this is configured as, when power from the outside is supplied by AC adapter or the like is connected to the DC connector, the external power is supplied to the DC / DC converter via the diode D ₁ In response, the DC / DC converter creates the voltage required by the device. In this case, the external power is not to be blocked by the diode D ₂ is applied to the secondary battery.

On the other hand, when power is supplied from the outside, power is supplied to the secondary battery and charging is performed only when the charger is operating because charging is instructed. . When the charger is stopped, power supply to the secondary battery is interrupted circuit by the main transistor Tr ₁ is not performed. When the external power supply is interrupted, the power of the secondary battery via the diode D ₂ is supplied to the DC / DC converter, a DC / DC converter to create a voltage required of the device accordingly. At this time, the power is blocked by the diodes D _{1 and} D ₄ and does not flow out.

When the charger power from outside is supplied is operated, the power created by the charger is supplied to the secondary battery via the diode D _4, it will be charged thereby rechargeable battery . At this time, the voltage input that is diode D ₂ by higher than the voltage of the charger is in the reverse bias state of the DC connector, not the charging current of the secondary battery from leaking to the DC / DC converter side.

When executing the charging process, the charging control unit constantly monitors the presence or absence of power supply from the DC connector and the ON / OFF state of the power supply of the device, and controls the ON / OFF control of the charger and the charging current. The switching control is executed. That charge, when power is supplied from the outside via the DC connector, sources of power device be in the OFF state when in a non-operating state, that is two steps prepared by controlling the resistor R ₅ to generate a larger one of the current charging the secondary battery, the charging current supply device apparatus be in the oN state when it is in operating state, that is two steps prepared by controlling the resistor R ₅ The control process of generating the smaller one of the above and charging the secondary battery is executed.

  In such a charging process, if the completion of charging is not accurately grasped and the charging is not terminated, there is a problem that the secondary battery is adversely affected and the battery life is shortened. For example, if the charge amount is insufficient, it is not possible to draw a sufficient capacity capacity as a battery, and the operating time of the device with the battery is reduced. In the case of secondary batteries such as Nicd, NiMH, and Li +, insufficient charging is only a problem that the rated capacity is not sufficient. However, in the case of secondary batteries such as lead-acid batteries, insufficient charging causes battery deterioration. Conversely, if the amount of charge is excessively increased to sufficiently draw out the capacity of the battery, an overcharged state occurs, which also causes deterioration of the battery.

  There are two ways to know that the rechargeable battery has been properly charged: using the time lapse from the start of charging, knowing that the voltage of the rechargeable battery has reached the maximum voltage, How to know when the temperature of the battery has reached the maximum temperature value, How to know when the temperature change rate of the secondary battery has reached the maximum temperature change rate, or the voltage of the secondary battery drops slightly to the completion stage of charging There is a method of knowing using the characteristic (−ΔV characteristic). However, in long-time charging in which the charging current value is smaller than the capacitance value, the maximum voltage control, the maximum temperature change rate control, and the -ΔV characteristic control cannot be used.

  From now on, conventionally, the method of detecting the completion of charging by using the time lapse control or the maximum temperature control has been conventionally adopted. Of these two methods, particularly, the completion of the charging is detected by using the lapse of time from the start of charging. Is widely used.

Further, in such a charging process, there is a case where a request to measure the discharge current of the secondary battery is sometimes issued. In response to such a request, conventionally, as shown in FIG. In addition to the sense resistor R ₀ for detecting the charge current of the battery, a configuration is provided in which a sense resistor R _x for detecting the discharge current of the secondary battery is provided, and the discharge current of the secondary battery is determined using the sense resistor R _x. Is detected.

  However, as in the prior art, when the power of the device is in the OFF state, the larger one of the two-stage prepared charging currents is generated to charge the secondary battery, and when the power of the device is in the ON state, However, if the method of charging the secondary battery by generating the smaller one of the charging currents prepared in two stages is employed, there is a problem that an efficient charging process cannot be executed.

  In other words, according to this conventional technique, the magnitude of the charging current must be set regardless of the magnitude of the current consumption of the device, so that the charging current when the power of the device is ON is the most. There is no other way but to set the lowest current consumption, which causes a problem that the charging process is not executed by maximizing the capacity of the external power such as the AC adapter.

  In addition, when the power of the device is turned on, the secondary battery is charged with a small charging current regardless of whether the device is actually operating. There was a problem that it was not running.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new charge control technique that enables a secondary battery to be charged efficiently.

(1) The present invention according to claim 1 The present invention according to claim 1 is an invention relating to an electronic device provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to the secondary battery by inputting an input voltage from the power supply, and (ii) a detector that detects an input voltage from the power supply And (iii) a charging control circuit that adjusts charging power supplied to the secondary battery by the charger according to the detected input voltage.

(2) The present invention according to claim 2 The present invention according to claim 2 is an invention relating to an electronic device provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to the secondary battery by inputting an input voltage from the power supply, and (ii) a detector that detects an input voltage from the power supply And (iii) the power supplied from the power supply to the load varies according to a load condition, and the charger supplies the secondary battery to the secondary battery according to the detected input voltage of the power supply. And a charge control circuit that adjusts the charging power to be applied.

(3) The present invention according to claim 3 The present invention according to claim 3 is an invention relating to an electronic apparatus provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to the secondary battery by inputting an input voltage from the power supply, and (ii) a detector that detects an input voltage from the power supply And (iii) a charging control circuit that controls the charger to generate the maximum charging power within a range in which the detected output voltage does not drop below the minimum allowable output voltage allowed by the power supply. Take.

(4) The present invention according to claim 4 The present invention according to claim 4 is an invention relating to a charging device provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In a charging device used in an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to a secondary battery by inputting an input voltage from the power supply, and (ii) an input voltage from the power supply And a charge control circuit that adjusts charging power supplied to the secondary battery by the charger in accordance with the input voltage detected by the detector that detects the charge.

(5) The present invention according to claim 5 The present invention according to claim 5 is an invention relating to a charging device provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In a charging device used in an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to a secondary battery by inputting an input voltage from the power supply, and (ii) the load from the power supply to the load. The power to be supplied changes according to the state of the load, and the charger supplies the secondary battery to the secondary battery in accordance with the input voltage of the power supply detected by the detector that detects the input voltage from the power supply. And a charge control circuit that adjusts the charging power to be applied.

(6) The present invention according to claim 6 The present invention according to claim 6 is an invention relating to a charging device provided with the present invention, in which an input voltage given from a power supply is applied to a load, and the input voltage is used as an input. In a charging device used in an electronic device capable of charging a secondary battery, (i) a charger that supplies charging power to a secondary battery by inputting an input voltage from the power supply, and (ii) an input voltage from the power supply And a charge control circuit that controls the charger to generate the maximum charging power within a range in which the output voltage detected by the detector that detects the voltage does not drop below the minimum allowable output voltage allowed by the power supply. Take.

(7) The present invention according to claim 7 The present invention according to claim 7 is an invention relating to a charge control circuit having the present invention, and uses a secondary voltage as an input from a power supply input for applying an input voltage to a load. In a charging control circuit for controlling a charger for charging a battery, (i) adjusting a charging current to be supplied to the secondary battery according to an input voltage detected by a detecting unit that detects a voltage of the power input. A configuration is provided in which control means is provided.

(8) The present invention according to claim 8 The present invention according to claim 8 is an invention relating to a charge control circuit provided with the present invention, in which an input voltage from a power supply input that applies an input voltage to a load is used as a secondary. In a charge control circuit for controlling a charger for charging a battery, (i) the power supplied to the load from the power supply input varies according to the load condition, and the input voltage from the power supply input In accordance with the input voltage detected by the detector for detecting the charging voltage.

(9) The present invention according to claim 9 The present invention according to claim 9 is an invention relating to a charge control circuit provided with the present invention, in which an input voltage from a power supply input that applies an input voltage to a load is used as a secondary. In a charge control circuit for controlling a charger that charges a battery, (i) an output voltage detected by a detector that detects an input voltage from the power supply input falls below a minimum allowable output voltage allowed by the power supply. In such a case, the charger has a control means for controlling the charger to generate the maximum charging current.

(10) The present invention according to claim 10 The present invention according to claim 10 is the charging control circuit according to any one of claims 7 to 9, wherein (i) charging current detecting means for detecting a charging current of the secondary battery detects the charging current. A configuration is provided in which means for controlling charging is provided so that the charging current thus obtained is equal to or less than the current value specified for the secondary battery.

(11) The present invention according to claim 11 The present invention according to claim 11 is the charging control circuit according to any of claims 7 to 10, wherein (i) the charging voltage detecting means for detecting the charging voltage of the secondary battery detects the charging voltage. A configuration is provided in which means for controlling charging is provided so that the charged voltage becomes equal to or lower than the voltage value specified for the secondary battery.

(12) The present invention described in claim 12 The present invention described in claim 12 employs a configuration in which the power supply is an AC adapter in the charging control circuit according to claims 7 to 11.

(13) The present invention according to claim 13 The present invention according to claim 13 is an invention relating to an electronic apparatus having the present invention, wherein the output is a constant voltage output at a predetermined current or less and the output is a constant voltage output or more. In an electronic device that has an input unit for inputting power from a power supply whose voltage decreases, and supplies an input from the input unit to a load, and charges a secondary battery using power from the input unit as an input, i) power input sensing means for sensing power input provided from the input unit and sensing power input information, and (ii) a charger for charging the secondary battery with current from the input unit as an input. (Iii) the current supplied from the input unit to the load changes according to the condition of the load, and the sum of the changing current and the current charged to the secondary battery from the input unit. Is virtually power So as not to come off the voltage region, in response to said power input sensed power input information sense means employs a configuration that includes a charge control circuit for controlling the charging current which the battery charger is given to the secondary battery.

(14) The present invention according to claim 14 The present invention according to claim 14 is an invention relating to a charging device provided with the present invention, wherein the output is a constant voltage output at a predetermined current or less and the output is a constant voltage output or more. Has an input unit for inputting power from a power source whose voltage decreases, and provides an input from the input unit to a load, and is used in an electronic device that charges a secondary battery using power from the input unit as an input. In the charging device, (i) a charger that charges the secondary battery with a current from the input unit as an input, and (ii) a current supplied to the load from the input unit changes according to a state of the load. And sensing a power input from the input unit so that a sum of the changing current and a current charged to the secondary battery from the input unit does not substantially fall outside a constant voltage region of a power supply. Power input sense Depending on the sensed power input information by stage, it employs a configuration that includes a charge control circuit for controlling the charging current which the battery charger is given to the secondary battery.

(15) The present invention according to claim 15 The present invention according to claim 15 is an invention relating to a charge control circuit having the present invention, wherein the output is a constant voltage output at a predetermined current or less, and the output is a constant voltage output at a predetermined current or more. The output is an input unit for inputting power from a power supply whose voltage decreases, and the input charges the secondary battery by inputting power from an input unit for supplying power to a load and a secondary battery. In the charging control circuit for the charger, (i) a current supplied from the input unit to the load changes according to a state of the load, and the changing current and the secondary current from the input unit According to the power input information sensed by the power input sensing means for sensing the power input from the input unit, so that the sum of the current charged to the battery does not substantially fall outside the constant voltage region of the power supply. The charger It employs a configuration that has a control means for controlling the charging current applied to the next cell.

(16) The present invention according to claim 16 In the present invention according to claim 16, in the charge control circuit according to claim 15, (i) the charging current is detected by a charging current detecting means for detecting a charging current of the secondary battery. According to the present invention, there is further provided a means for controlling the charging current such that the charging current is equal to or less than a value specified for the secondary battery in accordance with the charging current.

(17) The present invention according to claim 17 The invention according to claim 17 is the charging control circuit according to claims 15 to 16, wherein (i) the charging voltage detecting means for detecting the charging voltage of the secondary battery. The configuration further includes means for controlling the charging voltage so that the set voltage is equal to or less than the value specified for the secondary battery.

(18) The present invention according to claim 18 The present invention according to claim 18 is an invention relating to an electronic device having the present invention, which has an input unit for inputting power from a power supply, and receives an input from the input unit. In an electronic device capable of charging a secondary battery using power from the input unit as an input while providing an input to a load, (i) sensing power input from the input unit and sensing power input information Power input sensing means, (ii) a charger for charging the secondary battery with power from the input unit as an input, and (iii) a current supplied to the load from the input unit according to a state of the load. The battery charger determines whether or not the current output from the power supply has reached a predetermined value in accordance with the power input information sensed by the power input sensing means. Charge current By reduction, as the sum of the current and the charging current supplied to the load does not exceed the predetermined value, a configuration that has a charging control circuit for controlling the charger.

(19) The present invention according to claim 19 The present invention according to claim 19 is an invention relating to a charging device provided with the present invention, which has an input unit for inputting power from a power supply, and receives an input from the input unit. In a charging device used in an electronic device, an input is applied to a load, and a secondary battery is charged by using power from the input unit as an input, and a current applied to the load from the input unit changes according to a load condition. A) a charger for charging the secondary battery with power from the input unit as an input, and (ii) from the power source according to power input information sensed by power input sensing means for sensing power input from the input unit. By determining whether the output current has reached a predetermined value, the charging current given to the secondary battery by the charger is changed, and the sum of the current given to the load and the charging current becomes the predetermined value. So as not to exceed, it employs a configuration that includes a charge control circuit for controlling the charger.

(20) The present invention according to claim 20 The present invention according to claim 20 is an invention relating to a charge control circuit having the present invention, and is an input unit for inputting power from a power supply, wherein The input of the charging control circuit for a charger that charges the secondary battery by inputting power from an input unit that supplies power to a load and a secondary battery, (i) the load from the input unit to the load The current supplied to the power supply changes according to the load condition. According to the power input information sensed by the power input sensing means for sensing the power input from the input unit, the current output from the power supply is a predetermined value. By determining whether or not the value has become a value, by changing the charging current given to the secondary battery by the charger, so that the sum of the current given to the load and the charging current does not exceed the predetermined value , Charge It employs a configuration that has a charging control means for controlling the vessel.

(21) The present invention according to claim 21. The present invention according to claim 21, wherein in the charging control circuit according to claim 20, (i) the charging current is detected by charging current detecting means for detecting a charging current of the secondary battery. According to the present invention, there is further provided a means for controlling the charging current such that the charging current is equal to or less than a value specified for the secondary battery in accordance with the charging current.

(22) The present invention according to claim 22. The present invention according to claim 22, wherein in the charging control circuit according to claims 20 to 21, (i) the charging voltage detecting means for detecting the charging voltage of the secondary battery. The configuration further includes means for controlling the charging voltage so that the set voltage is equal to or less than the value specified for the secondary battery.

(23) The invention according to claim 23. The invention according to claim 23, wherein in the charge control circuit according to claims 20 to 22, (i) the predetermined value is a maximum supply power of the power supply. take.

  According to the present invention, according to the present invention, when an electronic device includes a secondary battery, the secondary battery can be charged with a maximum charging current in an allowable range of the secondary battery and an external power supply. Therefore, the secondary battery can be charged at the fastest speed when the electronic device operates.

  Hereinafter, the present invention will be described in detail according to embodiments.

  Prior to the description of the embodiments, a technique related to the present invention will be described.

  1 and 2 show the configuration of an electronic device 1 that implements the technology related to the present invention.

  The electronic device 1 illustrated in FIGS. 1 and 2 includes a load circuit 2 that executes signal processing, a secondary battery 3 that supplies power to the load circuit 2, and a secondary battery 3 that uses power supplied from an external power supply. And a charging circuit 4 for generating a charging current of

  The electronic device 1 illustrated in FIG. 1 includes a charging current detection unit 10 that detects a charging current flowing into the secondary battery 3, a consumption current detection unit 11 that detects a consumption current consumed by the load circuit 2, and a secondary battery. 3, a first detecting means 12 for detecting a difference value between a maximum allowable charging current permitted by the third power supply and a charging current detected by the charging current detecting means 10, a maximum suppliable current permitted by the external power supply, and a consumed current detecting means. A second detection means 13 for detecting a maximum usable current by detecting a difference value between the consumption current detected by the power supply 11 and a maximum usable current detected by the second detection means 13; A third detecting means 14 for detecting a difference value from the charging current detected by the second detecting means 14 and a third detecting means 14 for detecting a difference value between the maximum allowable applied voltage allowed by the secondary battery 3 and the voltage applied to the secondary battery 3. 4 detecting means 15 and charging circuit And a control unit 16 for controlling the charging current for generating the.

  The electronic device 1 illustrated in FIG. 2A includes a detecting unit 30 that detects a charging current flowing into the secondary battery 3, an integrating unit 31 that integrates the charging current detected by the detecting unit 30, and a charging circuit. And an issuing unit 32 for issuing a charge end instruction to the charging unit 4.

  The electronic device 1 shown in FIG. 2B has a sense for detecting a charging current flowing into the secondary battery 3 on a side closer to the secondary battery 3 than a connection point between the charging circuit 4 and the device power supply circuit. A current measurement that includes a resistor and receives a potential between both ends of the sense resistor as an input, and generates a voltage corresponding to a difference value between the two input potentials while identifying which of the two input potentials is larger. Means 41 are provided.

  In the electronic device 1 configured as described above and illustrated in FIG. 1, when the device is driven using power supplied from an external power supply, the control unit 16 includes the first detection unit 12 and the third detection unit 12. The charging current flowing into the secondary battery 3 does not exceed the maximum allowable charging current and the maximum usable current, and is applied to the secondary battery 3 according to the difference value detected by the detecting means 14 and the fourth detecting means 15. The charging circuit 4 controls so as to generate the maximum charging current within a range where the voltage does not exceed the maximum allowable applied voltage.

  That is, when any of the difference values detected by the first detection means 12, the third detection means 14, and the fourth detection means 15 exceeds the limit value, the difference value exceeding the limit value is specified. Then, when there is no value exceeding the limit value, the difference value closest to the zero value is specified, and the charging current generated by the charging circuit 4 is controlled so that the specified difference value becomes the zero value. .

  According to the control process of the control unit 16, in the electronic device 1 illustrated in FIG. 1, the charging of the secondary battery 3 is performed with the maximum charging current of the allowable range of the secondary battery 3 and the external power supply. When the electronic device 1 operates, the secondary battery 3 can be charged at the fastest speed.

  In addition, in the electronic device 1 illustrated in FIG. 2A configured as described above, the charging circuit 4 generates a charging current that changes according to the operating conditions of the device and charges the rechargeable battery 3. Then, the detecting means 30 detects the charging current flowing into the secondary battery 3, and upon receiving the detection result, the integrating means 31 integrates the detected charging current. 32 is to determine whether or not the sum of the integrated charging current amount and the current capacity of the secondary battery 3 at the start of charging has reached the maximum current capacity of the secondary battery 3; Issue a charge end instruction to the charging circuit 4.

  In this way, in the electronic device 1 illustrated in FIG. 2A, even if the charging current generated by the charging circuit 4 changes dynamically, the secondary battery 3 is used by using the charging current. This makes it possible to accurately detect the completion of charging the battery.

  In addition, in the electronic device 1 illustrated in FIG. 2B configured as described above, the charging circuit 4 uses the charging current detected by the sense resistor 40 to perform the constant current mode used for charging the secondary battery 3. , The discharge current of the secondary battery 3 also flows through the sense resistor 40. In response to the charging / discharging current flowing through the sense resistor 40, the current measuring means 41 has, for example, two output ports. When the charging current flows through the sense resistor 40, the current measuring means 41 supplies the charging current to one of the output ports. When a discharge current flows through the sense resistor 40, a voltage corresponding to the magnitude of the discharge current is output to the other output port.

  In this way, in the electronic device 1 shown in FIG. 2B, the sense resistor used for detecting the charging current and the sense resistor used for detecting the discharging current are shared, so that the charging of the secondary battery 3 is performed. The discharge current can be measured according to a simple configuration.

  FIG. 3 shows a configuration of an electronic device 1 (a detailed configuration of the one shown in FIG. 1) on which the technology related to the present invention is mounted.

  In the figure, 50 is a secondary battery, a rechargeable battery composed of battery cells connected in series, 51 is a DC connector, which is used when the device is operated with an AC adapter or when the device is built in with an AC adapter. Is a connector for receiving an external power supply when charging the secondary battery 50, and a DC / DC converter 52 is an external power supply supplied via the DC connector 51 or a power supply from the secondary battery 50. In response to this, a power supply for the device for generating a voltage required by the device, a charger 53 for charging the secondary battery 50 when power is supplied from the outside via the DC connector 51 A constant current source for generating electric power necessary for performing the control, a control circuit 54 is provided in the charger 53, and a control mechanism for executing a constant current control in accordance with a PWM control method; There, the measurement circuit for measuring charging and discharging currents of the secondary battery 50, 56 is a μ controller, a charge control mechanism for instructing the start and end of charge.

D ₁ and D _4, due to reasons such as the AC power to the AC adapter is not supplied, when the AC adapter is in the non-operating state, for power from the secondary battery 50 is prevented from flowing out It is a protection diode for backflow prevention. D ₂ supplies power from the secondary battery 50 to the DC / DC converter 52 when power is not supplied from outside, and when power is supplied from outside via the DC connector 51, This is a protection diode for preventing a voltage from being applied to the secondary battery 50.

Tr ₁ is a switching main transistor that performs ON / OFF operation in accordance with an instruction from the control circuit 54, L ₁ is a choke coil, D ₃ is a flywheel diode, and C ₁ is a smoothing capacitor.

R ₀ is a sense resistor for measuring a charge flow value flowing into the secondary battery 50. The voltage drop generated by the charge current flowing through the sense resistor R ₀ is divided by the resistors R _{1 and} R _2. while being inputted to the ERR1 terminal of the resistor R _3, R ₄ in divided by the control circuit 54. R ₆ is a sense resistor for measuring a consumption current value used by the device. The voltage drop due to the consumption current flowing through the sense resistor R ₆ is divided by the resistors R _{7 and} R ₈ and the resistance R _9, is divided by the R ₁₀ min inputted to ERR2 terminal of the control circuit 54.

The voltage e ₁ applied to the ACADP terminal of the control circuit 54 is for notifying the control circuit 54 of the maximum current value that can be supplied by the AC adapter, and is provided as a voltage value corresponding to the current value. E ₂ provided to the MAXC terminal of the control circuit 54 is for notifying the control circuit 54 of the maximum charging current value allowed by the secondary battery 50, and is provided as a voltage value corresponding to the current value. E ₃ given to the Vr terminal of the control circuit 54 is for notifying the control circuit 54 of the maximum applied voltage value allowed by the battery, and is given as a voltage value.

Tr ₂ prevents the potential of the secondary battery 50 from being applied to the control circuit 54 by disconnecting the ground side of the control circuit 54 when power is not supplied from the DC connector 51, and the resistance R 2 a switch circuit for protection to prevent from the secondary battery 50 via the ₁ to R ₄ of power leakage. R _21, R _22, when power from the DC connector 51 is not supplied, a voltage detection resistor for causing the switch OFF circuit Tr ₂ detects it.

  FIG. 4 illustrates an example of the control circuit 54.

  As shown in this figure, the control circuit 54 includes six error amplifiers 540-i (i = 1 to 6), a triangular wave oscillator 541, a PWM comparator 542, and a driver 543.

The first error amplifier 540-1 (ERA ₁₎ is an amplifier for measuring the voltage drop generated in the sense resistor R _0, and outputs a voltage proportional to the charging current flowing through the sense resistor R _0. The fourth error amplifier 540-4 (ERA ₄ ) calculates the charging current value output from the first error amplifier 540-1 and the maximum charging current value (e ₂ ) supplied to the MAXC terminal and allowed by the secondary battery 50. Is amplified and input to the PWM comparator 542.

Second error amplifier 540-2 (ERA ₂₎ is an amplifier for measuring the voltage drop generated in the sense resistor R _6, and outputs a voltage proportional to the consumption current flowing through the sense resistor R _6. The fifth error amplifier 540-5 (ERA ₅ ) has a current consumption value output from the second error amplifier 540-2, a maximum supply current value (e ₁ ) that can be supplied to the ACADP terminal and can be supplied by the AC adapter. Is amplified and output as the maximum usable current value.

The sixth error amplifier 540-6 (ERA ₆ ) is a difference value between the charging current value output from the first error amplifier 540-1 and the maximum usable current value output from the fifth error amplifier 540-5. Is amplified and input to the PWM comparator 542. The third error amplifier 540-3 (ERA ₃ ) includes a voltage applied to the secondary battery 50 input to the first error amplifier 540-1 and a maximum voltage applied to the Vr terminal that the secondary battery 50 allows. The difference value from the voltage value (e ₃ ) is amplified and input to the PWM comparator 542.

  Here, the error amplifier 540-i that receives the limit value outputs a specified voltage value when the measured value is equal to the limit value, and outputs the specified voltage value when the limit value is larger than the measured value. It operates to output a large voltage value and output a negative value or “0” when the measured value is larger than the limit value.

The triangular wave oscillator 541 generates a triangular wave voltage according to a specified cycle and inputs the voltage to the PWM comparator 542. The PWM comparator 542 receives the voltage values output from the fourth error amplifier 540-4, the sixth error amplifier 540-6, and the third error amplifier 540-3, and the triangular wave voltage output from the triangular wave oscillator 541. To generate a pulse having a pulse width corresponding to the input voltage. The driver 543 is a drive circuit for driving the main transistor Tr _{1. While} the PWM comparator 542 outputs a high level, the driver 543 turns on the main transistor Tr ₁ and the PWM comparator 542 outputs a low level. while you are, make OFF the main transistor Tr _1.

  FIG. 5 illustrates an example of the PWM comparator 542.

  The PWM comparator 542 shown in this figure is provided corresponding to the input voltages from the three error amplifiers, compares the output voltage of the error amplifier with the triangular wave voltage generated by the triangular wave oscillator 541, and determines the input triangular wave voltage. When the input triangular wave voltage is higher, the comparator circuit outputs a high level when the input triangular wave voltage is higher, and an AND circuit that calculates and outputs a logical product of output values of all the comparator circuits. From this, the comparison circuit generates a pulse having a pulse width corresponding to the output voltage of the error amplifier, and the comparison circuit associated with the error amplifier whose measured value exceeds the limit value has a negative value or By outputting “0”, the operation is performed so as not to generate a pulse.

  According to this configuration, when the input voltage from the error amplifier falls within the range of the limit value, as shown in FIG. Is not generated, and when it does not fall within the range, no pulse is generated. Then, the AND circuit of the PWM comparator 542 receives the outputs of these comparator circuits and outputs a pulse corresponding to the shortest one at the highest level as shown in FIG. 6B.

  That is, the PWM comparator 542 does not generate a pulse when any of the input voltages from the three error amplifiers exceeds the limit value, and generates the pulse when the input voltage from the three error amplifiers does not exceed the limit value. Is specified, and a high-level pulse having a length corresponding thereto is generated.

In response to the pulse generation of the PWM comparator 542, driver 543, while the PWM comparator 542 is outputting a high level, together with the turning ON of the main transistor Tr _1, the PWM comparator 542 outputs a low level During this time, by turning off the main transistor Tr ₁ , the magnitude of the charging current generated by the charger 53 is controlled so that the output voltage of the error amplifier from which the pulse of the PWM comparator 542 is generated becomes zero. I do.

In accordance with the control circuit 54 having this configuration, the charger 53 controls the charging current detected by the sense resistor R ₀ (the limit value is the maximum charging current value allowed by the secondary battery 50 and the fifth error amplifier 540-5). Of the maximum usable current output by the secondary battery 50) and the applied voltage to the secondary battery 50 (the limit value is the maximum applied voltage value allowed by the secondary battery 50). The secondary battery 50 is charged in accordance with the charging current limited by the amount that has been reached.

  In this way, the charging of the secondary battery 50 is performed with the maximum charging current in the allowable range of the secondary battery 50 and the AC adapter. It can be charged.

Still referring to the charging operation of the electronic device 1 shown in FIG. 3, the, the external power is DC / DC converter via the D ₁ when the power from the outside is supplied by AC adapter is connected to the DC connector 51 52, and the DC / DC converter 52 creates the voltage required by the device accordingly.

  At this time, when the μ controller 56 instructs the control circuit 54 to perform a charging operation, the control circuit 54 starts the following operation to generate a charging current.

That is, when the current consumption of the DC / DC converter 52 is detected by the sense resistor R _6, the maximum usable current value of the AC adapter that can be used in the current consumption state is obtained, and the detected value is detected by the sense resistor R _0. The charging current of the secondary battery 50 is controlled so as not to exceed the maximum usable current value, and the charging current is controlled so as not to exceed the maximum charging current value allowed by the secondary battery 50. Then, control is performed so that the applied voltage to the secondary battery 50 detected by the sense resistor R ₀ does not exceed the maximum applied voltage allowed by the secondary battery 50.

  Now, in the electronic device 1 shown in FIG. 3, the maximum charging current value allowed by the secondary battery 50 is 1000 mA, the battery capacity of the secondary battery 50 is 1000 mAH, the maximum current value that the AC adapter can supply is 1500 mA, Assuming that the maximum current consumption used during operation is 1100 mA, the average consumption current used during operation of the device is 400 mA, and the consumption current when the device is not operating is OmA, and applied to the secondary battery 50 Assume that there is no voltage limit.

  When the apparatus is in the stop state, all the current supplied from the AC adapter can be used as the charging current for the secondary battery 50, and thus, the battery can be charged at the maximum current value of 1000 mA allowed by the battery. Therefore, the charging time at this time is completed in about one hour.

  On the other hand, while the device is operating, the current consumption dynamically changes between 0 and 1100 mA. In the electronic device 1 shown in FIG. 3, the charging current value is changed from 1000 mA to 400 mA in accordance with this dynamic change. The charging is performed while dynamically changing the charging time. Since the average current consumption value of the device is 400 mA, this charging current value is also 1000 mA on average. This charging current value of 1000 mA is the same as the current value when the device is in the stop state, and therefore, it can be charged in about one hour even when the device is operating.

  As described above, in the electronic device 1 illustrated in FIG. 3, the function of measuring the current consumption value of the device is provided, and the charging current value of the charger 53 is dynamically changed according to the current consumption of the device. Since the charging method is always performed with the maximum capacity of the AC adapter, the charging time of the secondary battery 50 can be significantly reduced.

  On the other hand, the prior art does not employ a configuration for dynamically detecting the power consumption of the device that dynamically changes, and thus the design is made in consideration of the maximum power consumption. From this, when the maximum power consumption during operation of the device is 1100 mA and the maximum current value that can be supplied by the AC adapter is 1500 mA, the current value that can be used by the charger 53 is 400 mA. At any time, charging is always performed at 400 mA regardless of the current consumption value, and a charging time of about 3 hours is required.

  As described above, in the electronic device 1 illustrated in FIG. 3, by performing charging in accordance with the capability of the external power supply, the charging time of the secondary battery 50 can be significantly reduced.

  Next, the functions of the current measuring circuit 55 and the μ controller 56 provided in the electronic device 1 shown in FIG. 3 will be described.

The current measuring circuit 55 is provided for measuring the magnitude of the current flowing through the sense resistor _R0 .

As described above, this sense resistor R ₀ functions as a constant current control resistor of the charger 53, and is provided in the path of the discharge current of the secondary battery 50, as can be seen from the circuit configuration of FIG. That is, when the secondary battery 50 is charged, a charging current flows through the sense resistor R ₀ , while when the AC adapter is not connected to the DC connector 51, the power of the secondary battery 50 is supplied to the DC / DC converter 52. Therefore, a discharge current flows through the sense resistor _R0 . Therefore, the current measuring circuit 55 measures both the charging current flowing into the secondary battery 50 and the discharging current flowing out of the secondary battery 50.

  FIG. 7 shows an example of the current measuring circuit 55.

As shown in this figure, the current measuring circuit 55 includes a first operational amplifier 550-1 (OP _1), the second operational amplifier 550-2 and (OP _2), third operational amplifier 550-3 ( OP ₃ ) and a fourth operational amplifier 550-4 (OP ₄ ). The first operational amplifier 550-1 (OP ₁ ) inputs one potential of the sense resistor R ₀ to the + terminal. as well as, - terminal resistor R ₃₁ a via in the second operational amplifier 550-2 - connected to a terminal, the second operational amplifier 550-2 is input to the other potential of the sense resistor R ₀ to the positive terminal to together, - via a resistor R ₃₁ terminal first operational amplifier 550-1 - connected to a terminal, a third operational amplifier 550-3 is the resistance the output voltage of the first operational amplifier 550-1 through R ₃₄ - together with the input to the terminal, connected to the ground the + terminal via the resistor R _37, the fourth operational amplifier 55 -4 output voltage of the second operational amplifier 550-2 via the R ₄₁ - together with the input to the terminal is connected to ground + terminal via the resistor R _44.

  According to this configuration, the current measurement circuit 55 amplifies the difference value between the voltage input to the + terminal of the first operational amplifier 550-1 and the voltage input to the + terminal of the second operational amplifier 550-2. And output.

That is, when the input potential of the + terminal of the first operational amplifier 550-1 is higher than the input potential of the + terminal of the second operational amplifier 550-2, the third operational amplifier 550-3 has a potential difference between the two. And outputs a voltage proportional to the value of the discharge current flowing through the sense resistor _R0 . When the input potential of the + terminal of the first operational amplifier 550-1 is lower than the input potential of the + terminal of the second operational amplifier 550-2, the fourth operational amplifier 550-4 has a potential difference between the two. And outputs a voltage proportional to the value of the charging current flowing through the sense resistor _R0 .

In this way, the current measuring circuit 55, and both the charging current and the discharging current flowing through the sense resistor R ₀ in a measurement target, identify whether the current flowing through the sense resistor R ₀ that is to whether the discharge current is the charging current Then, a voltage value corresponding to the magnitude of the current value is generated.

  On the other hand, the μ controller 56 receives the measurement result of the current measurement circuit 55 and controls the control circuit 54 to perform the charge control process.

  FIG. 8 shows a processing flow executed by the μ controller 56.

  When the power is turned on, the μ controller 56 first detects whether or not the AC adapter is attached in Step 1 as shown in the processing flow of FIG. Although not shown in FIG. 3, this detection process is executed by monitoring the output voltage of the AC adapter.

When it is detected in step 1 that the AC adapter is attached, the process proceeds to step 2 where the control circuit 54 is activated to instruct execution of charging of the secondary battery 50. The remaining battery level of the stored secondary battery 50 is read. Subsequently, in step 4, the output voltage of the current measuring circuit 55 is read to read the charging current flowing through the sense resistor R ₀ , and the accumulated current is read to update the remaining battery level of the secondary battery 50. .

  Subsequently, in step 5, it is detected whether or not an instruction to stop the device has been issued, and when it is detected that the instruction to stop the device has not been issued, the process proceeds to step 6, where the remaining battery level to be updated is updated. It is determined whether the amount has reached full charge. When it is determined that the battery has not reached the full charge, the process returns to step 4 to continue updating the remaining battery power. When it is determined that the battery has reached the full charge, the process proceeds to step 7 and the control circuit 54 is stopped. Then, in the following step 8, the remaining battery level is saved and the process is terminated.

  If it is detected in step 5 that an instruction to stop the apparatus has been issued, the process immediately proceeds to step 7, in which the control circuit 54 is stopped, and in step 8, the remaining battery level is saved and the process is terminated. .

On the other hand, if it is determined in step 1 that the AC adapter is not attached, that is, if the power of the secondary battery 50 is to be supplied to the DC / DC converter 52, the process proceeds to step 9 to save the saved secondary battery. The remaining battery level of the next battery 50 is read. Subsequently, in step 10, the output voltage of the current measurement circuit 55 is read to read the discharge current flowing through the sense resistor R ₀ , and the output is integrated to update the remaining battery level of the secondary battery 50. . Subsequently, in step 11, it is detected whether or not an instruction to stop the device has been issued. If it is detected that the instruction to stop the device has not been issued, the process returns to step 10 to update the remaining battery level. If the process is continued and it is detected that the instruction to stop the device has been issued, the process proceeds to step 8, where the remaining battery level is saved, and the process ends.

  In this manner, even when the charging current generated by the charger 53 changes dynamically, the μ controller 56 accurately detects the completion of charging of the secondary battery 50 and stops the charging. It goes.

  Although the electronic device 1 shown in FIG. 3 adopts a configuration in which the maximum current value that can be supplied from the AC adapter is input to the ACADP terminal of the control circuit 54 in advance, the power supply of the AC adapter is performed by using the characteristics of the AC adapter. It is also possible to adopt a configuration for automatically detecting the capability, and by using this, it is possible to realize the electronic device 1 of the present invention, which can be made more practical.

  FIG. 9 illustrates an example of the correspondence between the output current value and the output voltage value of the AC adapter. This AC adapter indicates that the rated output voltage is 16.0 V and the rated output current value is 1500 mA.

  As shown in this figure, when the output current value is within the rated output current value such as 0 to 1500 mA, the AC adapter maintains the voltage output of the rated output voltage value. Then, the output voltage value is reduced to, for example, 15.0 V to notify the load side of the overload state, and when a larger current value is required, a heavy overload state occurs and the voltage output is cut off. It has a function to go.

  This means that when the output voltage value of the AC adapter has dropped to the specified minimum allowable output voltage value, the limit of the power supply capability of the AC adapter has been reached. When the output voltage value of the adapter drops to the minimum allowable output voltage value, the charging current of the charger 53 is limited, so that the maximum supply of the AC adapter requested to be input to the control circuit 54 by the electronic device 1 shown in FIG. This means that the current value can be omitted.

  FIG. 10 illustrates an embodiment of the present invention using this method.

  Prior to the description of FIG. 10, an outline of the present invention according to this embodiment will be described with reference to FIG.

  In the figure, reference numeral 1 denotes an electronic device having the present invention, which includes a load circuit 2 for executing signal processing, a secondary battery 3 for supplying power to the load circuit 2, and a secondary battery 3 using power supplied from an external power supply. And a charging circuit 4 for generating a charging current for the secondary battery 3.

  The electronic device 1 of the present invention includes a charging current detecting unit 20 for detecting a charging current flowing into the secondary battery 3, a maximum allowable charging current allowed by the secondary battery 3, and a charging current detected by the charging current detecting unit 20. First detecting means 21 for detecting a difference value between the external power supply, a second detecting means 22 for detecting a difference value between a minimum allowable output voltage allowed by the external power supply and a voltage output from the external power supply, A third detecting means 23 for detecting a difference value between a maximum allowable applied voltage permitted by the third battery 3 and a voltage applied to the secondary battery 3, and a control means 24 for controlling a charging current generated by the charging circuit 4. Prepare.

  The electronic device 1 of the present invention configured as described above uses the characteristic that when the current consumption (power) required by the load circuit 2 increases, the power supply voltage supplied from the external power supply decreases. When the load is being driven by using the control unit 24, the control unit 24 controls the secondary battery 3 according to the difference value detected by the first detection unit 21, the second detection unit 22, and the third detection unit 23. The charging current flowing into the battery does not exceed the maximum allowable charging current, the output voltage output from the external power supply does not drop below the minimum allowable output voltage, and the voltage applied to the secondary battery 3 is the maximum allowable applied voltage. The charging circuit 4 is controlled so as to generate the maximum charging current within a range not exceeding.

  That is, when any of the difference values detected by the first detection means 21, the second detection means 22, and the third detection means 23 exceeds the limit value, the difference value exceeding the limit value is specified. Then, when there is no value exceeding the limit value, the difference value closest to the zero value is specified, and the charging current generated by the charging circuit 4 is controlled so that the specified difference value becomes the zero value. .

  According to the control processing of the control means 24, in the electronic device 1 of the present invention, the charging of the secondary battery 3 is performed with the maximum charging current in the allowable range of the secondary battery 3 and the external power supply. In operation 1, the secondary battery 3 can be charged at the fastest speed.

  In this manner, the present invention uses the characteristic that when the current consumption (power) required by the load circuit 2 increases, the power supply voltage supplied from the external power supply decreases, and the charging current is reduced to a point where the decrease appears. By increasing the size, the secondary battery 3 is charged at a high speed.

  Next, FIG. 10 will be described. Here, in FIG. 10, the same components as those described in FIG. 3 are indicated by the same symbols.

That is different from the electronic apparatus 1 shown in FIG. 3, instead of having a sense resistor R ₆ and a resistor R ₇ to R _10, the resistance for monitoring the output voltage of the AC adapter connected to the DC connector 51 R ₁₁ , it adopts a configuration with R _12, an output voltage of the AC adapter is pressed by the resistor R _11, R ₁₂ min, in that it employs a configuration input to ERR2- terminal of the control circuit 54. Incidentally, the voltage value e ₁ corresponding to the maximum charging current value that allows the secondary battery 50 is input to ERC1 terminal of the control circuit 54. Further, the electronic device 1 shown in FIG. 3 adopts a configuration in which the maximum applied voltage value of the secondary battery 50 given from outside is generated inside the control circuit 54.

  FIG. 12 shows an embodiment of the control circuit 54 used in the electronic device 1 of the present invention shown in FIG.

  As shown in this figure, the control circuit 54 used in the electronic device 1 of the present invention shown in FIG. 10 has six errors included in the control circuit 54 (shown in FIG. 4) used in the electronic device 1 shown in FIG. Instead of the amplifier 540-i, a configuration including four error amplifiers 544-i (i = 1 to 4) is adopted.

The first error amplifier 544-1 (ERA ₁₎ is an amplifier for measuring the voltage drop generated in the sense resistor R _0, and outputs a voltage proportional to the charging current flowing through the sense resistor R _0. The third error amplifier 544-3 (ERA ₃ ) calculates a charging current value output from the first error amplifier 544-1 and a maximum charging current value (e ₁ ) allowed to the secondary battery 50 and supplied to the ERC1 terminal. Is amplified and input to the PWM comparator 542.

The second error amplifier 544-2 (ERA ₂ ) includes a voltage applied to the secondary battery 50 input to the first error amplifier 544-1 and a maximum voltage allowed by the secondary battery 50 given by the internal battery. The difference value from the voltage value is amplified and input to the PWM comparator 542. Fourth error amplifier 544-4 (ERA ₄₎ is the output voltage of the AC adapter, which is detected by the resistor R _11, R _12, set minimum allowable output voltage of the AC adapter provided by built-in battery (for example, 15.0V ) Is amplified and input to the PWM comparator 542.

Receiving the voltage values output from the third error amplifier 544-3, the second error amplifier 544-2, and the fourth error amplifier 544-4, and the triangular wave voltage output from the triangular wave oscillator 541, a PWM comparison is performed. The comparator 542 generates a pulse having a pulse width corresponding to the input voltage, and upon receiving this pulse, the driver 543 turns on the main transistor Tr ₁ while the PWM comparator 542 outputs a high level. while the PWM comparator 542 is outputting a low level, the OFF state of the main transistor Tr _1.

  The PWM comparator 542 is provided corresponding to the input voltages from the three error amplifiers as described with reference to FIG. 5, and compares the output voltage of the error amplifier with the triangular wave voltage generated by the triangular wave oscillator 541. A comparison circuit that outputs a high level when the input triangular wave voltage is smaller, and outputs a low level when the input triangular wave voltage is larger, and an AND circuit that calculates and outputs the logical product of the output values of all the comparison circuits Consists of From this, the comparison circuit generates a pulse having a pulse width corresponding to the output voltage of the error amplifier, and the comparison circuit associated with the error amplifier whose measured value exceeds the limit value has a negative value or By outputting “0”, the operation is performed so as not to generate a pulse.

  According to this configuration, as shown in FIG. 6A, when the input voltage from the error amplifier falls within the range of the limit value, each adder circuit of the PWM comparator 542 has a longer high level as a margin. When a pulse is generated and is not within the range, no pulse is generated. Then, the AND circuit of the PWM comparator 542 receives the outputs of these comparator circuits and outputs a pulse corresponding to the shortest one at the highest level as shown in FIG. 6B.

  That is, the PWM comparator 542 does not generate a pulse when any of the input voltages from the three error amplifiers exceeds the limit value, and generates the pulse when the input voltage from the three error amplifiers does not exceed the limit value. Is specified, and a high-level pulse having a length corresponding thereto is generated.

In response to the pulse generation of the PWM comparator 542, driver 543, while the PWM comparator 542 is outputting a high level, together with the turning ON of the main transistor Tr _1, the PWM comparator 542 outputs a low level During this time, by turning off the main transistor Tr ₁ , the magnitude of the charging current generated by the charger 53 is controlled so that the output voltage of the error amplifier from which the pulse of the PWM comparator 542 is generated becomes zero. I do.

According to the control circuit 54 having this configuration, the charger 53 sends the charging current detected by the sense resistor R ₀ (the limit value is the maximum charging current value allowed by the secondary battery 50) to the secondary battery 50. (its limit value, the maximum applied voltage value that allows the secondary battery 50) voltage applied between the resistor R _11, AC adapter output voltage detected by the R ₁₂ (the limit, lowest AC adapter The secondary battery 50 is charged in accordance with the charging current limited by the one that first reaches the limit value among the allowable output voltage values. That is, the charging current generated by the charger 53 is not limited to the maximum output current value allowed by the AC adapter.

  In this way, the charging of the secondary battery 50 is performed with the maximum charging current in the allowable range of the secondary battery 50 and the AC adapter. It can be charged.

  Now, in the electronic device 1 of the present invention shown in FIG. 10, the maximum charging current value allowed by the secondary battery 50 is 1000 mA, the battery capacity of the secondary battery 50 is 1000 mAH, and the maximum current value that can be supplied by the AC adapter is Assuming 1500 mA, the maximum current consumption when the device is operating is 1100 mA, the average current consumption when the device is operating is 400 mA, the current consumption when the device is not operating is OmA, and the secondary battery Assume that 50 has no applied voltage limitation.

  When the apparatus is in the stop state, all the current supplied from the AC adapter can be used as the charging current for the secondary battery 50, and thus, the battery can be charged at the maximum current value of 1000 mA allowed by the battery. Therefore, the charging time at this time is completed in about one hour.

  On the other hand, when the device is operating, the current consumption dynamically changes between 0 and 1100 mA, but it is assumed that the current consumption of the device is now 1000 mA. The charger 53 operates to output 1000 mA because the maximum allowable charging current value of the secondary battery 50 is 1000 mA. However, when the charging current generated by the charger 53 reaches 500 mA, the load current value of the AC adapter becomes 1500 mA, and the output voltage of the AC adapter starts drooping from the point of time exceeding this 1500 mA. As described above, the control circuit 54 operates to monitor the output voltage of the AC adapter and limit the output of the charger 53 at the point where the output voltage starts to decrease. Charging current is limited to a value of 500 mA.

  When the current consumption value of the device increases to 1100 mA, the voltage drop of the AC adapter occurs with the increase of the current consumption value. Therefore, the charger 53 further reduces the charging current value generated according to the instruction of the control circuit 54. And reduce it to 400mA. Subsequently, when the current consumption of the device decreases to 800 mA, the output voltage of the AC adapter returns to the rated voltage. As a result, since the limitation by the output voltage value of the AC adapter becomes free, the charger 53 increases the charging current generated according to the instruction of the control circuit 54, and when the charging current is increased to 700 mA, A voltage droop point is encountered where the current is limited.

  In this way, according to the present invention, charging is performed while dynamically changing the charging current value between 1000 mA and 400 mA in accordance with the dynamic change of the current consumption value of the device according to the capacity of the AC adapter. Become. Since the average current consumption value of the device is 400 mA, this charging current value is also 1000 mA on average. This charging current value of 1000 mA is the same as the current value when the device is in the stop state, and therefore, it can be charged in about one hour even when the device is operating.

  As described above, in the present invention, the function of measuring the current consumption value of the device side by monitoring the output voltage of the AC adapter is provided, and the charging current value of the charger 53 is dynamically changed according to the current consumption of the device side. By adopting a method of always charging with the maximum capacity of the AC adapter, the charging time of the secondary battery 50 can be significantly reduced.

  On the other hand, the prior art does not employ a configuration for dynamically detecting the power consumption of the device that dynamically changes, and thus the design is made in consideration of the maximum power consumption. From this, when the maximum power consumption during operation of the device is 1100 mA and the maximum current value that can be supplied by the AC adapter is 1500 mA, the current value that can be used by the charger 53 is 400 mA. At any time, charging is always performed at 400 mA regardless of the current consumption value, and a charging time of about 3 hours is required.

  As described above, according to the present invention, by performing charging in accordance with the capacity of the AC adapter, the charging time of the secondary battery 50 can be significantly reduced.

  Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited thereto. For example, in the embodiment, the present invention is disclosed using the secondary battery 50 whose applied voltage is limited. However, it is also possible to use the secondary battery 50 whose applied voltage is not limited. It is not necessary to adopt a configuration in which the charging current is limited by the applied voltage.

  (Supplementary Note 1) The apparatus includes a charging circuit that drives a device using power supplied from an external power supply and generates a charging current by using the external power as an input. The device has a charging current generated by the charging circuit. In an electronic device having a configuration for charging a secondary battery, first detection means for detecting a difference value between a maximum allowable charging current allowed by the secondary battery and a charging current flowing into the secondary battery; Second detecting means for detecting a maximum usable current by detecting a difference value between a maximum suppliable current allowed by the apparatus and a current consumption of the apparatus; the maximum usable current; and a charge flowing into the secondary battery. A third detecting means for detecting a difference value from the current, and a charging current flowing into the secondary battery according to the difference value detected by the first and third detecting means, the maximum allowable charging current and the maximum usable current. Range that does not exceed the current In, that a control means for controlling the so charging circuit for generating a maximum charging current, the charging control method according to claim.

  (Supplementary Note 2) The charging control method according to Supplementary Note 1, further comprising: fourth detection means for detecting a difference value between a maximum allowable applied voltage allowed by the secondary battery and a voltage applied to the secondary battery, and In accordance with the present invention, the charging current flowing into the secondary battery does not exceed the maximum allowable charging current and the maximum usable current and is applied to the secondary battery according to the difference value detected by the first, third, and fourth detecting means. A charging circuit for controlling the charging circuit to generate a maximum charging current within a range in which the applied voltage does not exceed the maximum allowable applied voltage.

  (Supplementary Note 3) The apparatus includes a charging circuit that drives the device using power supplied from an external power supply and generates a charging current by using the external power as an input, and includes a charging circuit that uses the charging current generated by the charging circuit. In an electronic device having a configuration for charging a secondary battery, first detection means for detecting a difference value between a maximum allowable charging current allowed by the secondary battery and a charging current flowing into the secondary battery; A second detecting means for detecting a difference value between a minimum allowable output voltage allowed by the external power supply and an output voltage output from the external power supply; and a secondary battery according to the difference value detected by the first and second detecting means. As long as the charging current flowing into the charging circuit does not exceed the maximum allowable charging current and the output voltage output from the external power supply does not drop below the minimum allowable output voltage, the charging circuit generates the maximum charging current. Control to control Further comprising a stage, a charge control method according to claim.

  (Supplementary note 4) The charging control method according to supplementary note 3, further comprising a third detection unit that detects a difference value between a maximum allowable applied voltage allowed by the secondary battery and a voltage applied to the secondary battery. According to the means, the charging current flowing into the secondary battery does not exceed the maximum allowable charging current and the output voltage output from the external power supply has the minimum allowable voltage according to the difference value detected by the first, second and third detecting means. Processing to control the charging circuit to generate the maximum charging current within a range that does not drop below the output voltage and that the voltage applied to the secondary battery does not exceed the maximum allowable applied voltage. , Charging control method characterized.

  (Supplementary Note 5) In the charging control method according to Supplementary Note 1, 2, 3, or 4, when there is a difference value detected by the detection unit that exceeds the limit value, the control unit may determine the difference that exceeds the limit value most. Specify the value, and when there is no value exceeding the limit value, specify the difference value closest to zero value and control the charging current generated by the charging circuit so that the specified difference value becomes zero value. A charging control method characterized by performing the following processing.

  (Supplementary Note 6) An electronic apparatus having a configuration in which a charging circuit that generates a charging current that changes in accordance with an operation condition of the device is provided and the secondary battery of the device is charged using the charging current generated by the charging circuit. Detecting means for detecting the charging current flowing into the secondary battery, integrating means for integrating the charging current detected by the detecting means, amount of charging current integrated by the integrating means, Issuing means for determining whether or not the total value of the current capacity has reached the maximum current capacity of the secondary battery, and issuing a charge termination instruction to the charging circuit when determining the reaching. , Charging control method characterized.

  (Supplementary Note 7) In an electronic device including a secondary battery that supplies power to an apparatus power supply circuit and a charging circuit that generates a constant current used for charging the secondary battery, a charging current flowing into the secondary battery is detected. Is provided on the secondary battery side from the connection point between the device power supply circuit and the charging circuit, so that the discharge current from the secondary battery can be measured using the sense resistor. While taking the potentials at both ends of the sense resistor as inputs, while identifying which of the two input potentials is greater, generating a voltage corresponding to the difference value between the two input potentials, the charging current and An electronic device, comprising: a current measuring unit that detects a discharge current.

  (Supplementary Note A) A configuration in which a load is driven by using power supplied from an external power supply, and a charging circuit that generates a charging current using the external power as an input is provided, and a secondary battery is charged using the charging current. A charging control device used in an electronic device, comprising: a unit configured to detect a difference value between a maximum allowable charging current allowed by a secondary battery and a charging current flowing into the secondary battery; Means for detecting a difference value between the permissible output voltage and the output voltage output from the external power supply, and a charging current flowing into the secondary battery does not exceed the maximum permissible charging current according to the two difference values, and Means for controlling the charging circuit to generate a maximum charging current within a range in which the output voltage output from the external power supply does not drop below the minimum allowable output voltage.

  (Supplementary note B) The charging control device according to supplementary note A, further comprising means for detecting a difference value between a maximum allowable applied voltage allowed by the secondary battery and a voltage applied to the secondary battery, wherein the controlling means includes: According to the three difference values, the charging current flowing into the secondary battery does not exceed the maximum allowable charging current, and the output voltage output from the external power supply does not drop below the minimum allowable output voltage, and A charging control device that performs processing to control the charging circuit to generate a maximum charging current within a range in which a voltage applied to the next battery does not exceed the maximum allowable applied voltage.

  (Supplementary Note C) In the charging control device according to Supplementary Note A or B, when there is a difference value that exceeds a limit value, the control unit specifies a difference value that exceeds the limit value most, and specifies the difference value. When there is nothing exceeding the value, specifying the difference value closest to the zero value, processing to control the charging current generated by the charging circuit so that the specified difference value becomes the zero value, Characteristic charge control device.

FIG. 1 is a configuration diagram of an electronic device that implements a technology related to the present invention. FIG. 1 is a configuration diagram of an electronic device that implements a technology related to the present invention. FIG. 1 is a configuration diagram of an electronic device that implements a technology related to the present invention. It is an example of a control circuit. It is an example of a PWM comparator. FIG. 5 is an explanatory diagram of the operation of the PWM comparator. It is an example of a current measurement circuit. 5 is a processing flow executed by a μ controller. It is a characteristic view of an AC adapter. It is an embodiment of the present invention. 1 is a schematic configuration diagram of the present invention. 3 is an example of an embodiment of a control circuit. It is explanatory drawing of a prior art. It is explanatory drawing of a prior art.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Load circuit 3 Secondary battery 4 Charging circuit 20 Charging current detecting means 21 First detecting means 22 Second detecting means 23 Third detecting means 24 Control means

Claims (23)

An electronic device capable of charging a secondary battery with an input voltage given from a power supply to a load and the input voltage being an input,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
A detector for detecting an input voltage from the power supply;
A charging control circuit that adjusts charging power supplied to the secondary battery by the charger in accordance with the detected input voltage,
Electronic equipment characterized. An electronic device capable of charging a secondary battery with an input voltage given from a power supply to a load and the input voltage being an input,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
A detector for detecting an input voltage from the power supply;
The power supplied from the power supply to the load changes depending on the load condition, and adjusts the charging power supplied to the secondary battery by the charger according to the detected input voltage of the power supply. And a charge control circuit that performs
Electronic equipment characterized. An electronic device capable of charging a secondary battery with an input voltage given from a power supply to a load and the input voltage being an input,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
A detector for detecting an input voltage from the power supply;
A charging control circuit that controls the charger to generate maximum charging power, in a range where the detected output voltage does not drop below the minimum allowable output voltage allowed by the power supply.
Electronic equipment characterized. A charging device, which is used in an electronic device capable of charging a secondary battery using the input voltage as an input while applying an input voltage given from a power supply to a load,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
A charging control circuit that adjusts charging power supplied to the secondary battery by the charger according to an input voltage detected by a detector that detects an input voltage from the power supply,
Characteristic charging device. A charging device, which is used in an electronic device capable of charging a secondary battery using the input voltage as an input while applying an input voltage given from a power supply to a load,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
The power supplied from the power supply to the load varies depending on the load condition, and the charger operates according to an input voltage of the power supply detected by a detector that detects an input voltage from the power supply. Having a charge control circuit for adjusting the charge power supplied to the secondary battery,
Characteristic charging device. A charging device, which is used in an electronic device capable of charging a secondary battery using the input voltage as an input while applying an input voltage given from a power supply to a load,
A charger that supplies charging power to a secondary battery with an input voltage from the power supply as an input,
Charge control for controlling the charger to generate maximum charging power within a range in which an output voltage detected by a detector that detects an input voltage from the power supply does not drop below a minimum allowable output voltage allowed by the power supply. Having a circuit
Characteristic charging device. A charge control circuit that controls a charger that charges a secondary battery with an input voltage from a power supply input that provides an input voltage to a load,
Having control means for adjusting a charging current supplied to the secondary battery in accordance with the input voltage detected by the detection means for detecting the voltage of the power supply input,
Characteristic charge control circuit. A charge control circuit that controls a charger that charges a secondary battery with an input voltage from a power supply input that provides an input voltage to a load,
The power supplied from the power supply input to the load varies depending on the load condition, and the charger operates according to an input voltage detected by a detector that detects an input voltage from the power supply input. Having control means for adjusting the charging power supplied to the secondary battery,
Characteristic charge control circuit. A charge control circuit that controls a charger that charges a secondary battery with an input voltage from a power supply input that provides an input voltage to a load,
The charger is controlled so as to generate a maximum charging current within a range in which an output voltage detected by a detector that detects an input voltage from the power supply input does not drop below a minimum allowable output voltage allowed by the power supply. Having control means,
Characteristic charge control circuit.   The battery control method according to claim 1, further comprising: means for controlling charging such that the charging current detected by the charging current detecting means for detecting the charging current of the secondary battery is equal to or less than a current value specified for the secondary battery. The charging control circuit according to any one of claims 7 to 9.   The apparatus according to claim 1, further comprising means for controlling charging such that the charging voltage detected by the charging voltage detecting means for detecting the charging voltage of the secondary battery is equal to or lower than a voltage value specified for the secondary battery. The charge control circuit according to any one of claims 7 to 10.   The charging control circuit according to claim 7, wherein the power supply is an AC adapter. An output that is a constant voltage output at an output equal to or lower than a predetermined current, and has an input unit that inputs power from a power supply whose voltage decreases at an output equal to or higher than the predetermined current, and provides an input from the input unit to a load, In an electronic device that charges a secondary battery using power from the unit as an input,
Power input sensing means for sensing power input provided from the input unit and sensing power input information;
A charger that charges the secondary battery with a current from the input unit as an input,
The current supplied from the input unit to the load changes according to the state of the load, and the sum of the changing current and the current charged to the secondary battery from the input unit is substantially equal to the current. A charging control circuit that controls a charging current supplied to the secondary battery by the charger according to the power input information sensed by the power input sensing means so as not to deviate from a constant voltage region of the power supply.
Electronic equipment characterized. An output that is a constant voltage output at an output equal to or lower than a predetermined current, and has an input unit that inputs power from a power supply whose voltage decreases at an output equal to or higher than the predetermined current, and provides an input from the input unit to a load, and In a charging device used in an electronic device that charges a secondary battery using power from the unit as an input,
A charger that charges the secondary battery with a current from the input unit as an input,
The current supplied from the input unit to the load changes according to the state of the load, and the sum of the changing current and the current charged to the secondary battery from the input unit is substantially equal to the current. The charging current supplied to the secondary battery by the charger is controlled according to the power input information sensed by the power input sensing means for sensing the power input from the input unit so as not to deviate from the constant voltage region of the power supply. Having a charge control circuit,
Characteristic charging device. An input unit for inputting power from a power source that outputs a constant voltage at an output equal to or lower than a predetermined current and decreases in voltage at an output equal to or higher than the predetermined current, wherein the input supplies power to a load and a secondary battery. In a charge control circuit for a charger that charges the secondary battery with power from an input unit being an input,
The current supplied from the input unit to the load changes according to the state of the load, and the sum of the changing current and the current charged to the secondary battery from the input unit is substantially equal to the current. The charging current supplied to the secondary battery by the charger is controlled according to the power input information sensed by the power input sensing means for sensing the power input from the input unit so as not to deviate from the constant voltage region of the power supply. Having control means,
Characteristic charge control circuit.   Means for controlling the charging current such that the charging current is equal to or less than a value specified for the secondary battery in accordance with the charging current detected by the charging current detection means for detecting the charging current of the secondary battery. The charging control circuit according to claim 15, further comprising:   The apparatus further comprises means for controlling a charging voltage such that a voltage detected by charging voltage detecting means for detecting a charging voltage of the secondary battery is equal to or less than a value specified for the secondary battery. Item 17. The charge control circuit according to Item 15 or 16. An electronic device having an input unit for inputting power from a power supply, and applying an input from the input unit to a load, and charging a secondary battery using power from the input unit as input.
Power input sensing means for sensing power input provided from the input unit and sensing power input information;
A charger that charges the secondary battery using power from the input unit as an input,
The current supplied from the input unit to the load changes according to the state of the load. According to the power input information sensed by the power input sensing means, the current output from the power supply becomes a predetermined value. By determining whether or not the charging current supplied to the secondary battery by the charger is changed, the charger so that the sum of the current supplied to the load and the charging current does not exceed the predetermined value. And a charge control circuit for controlling
Electronic equipment characterized. An input unit for inputting power from a power source, and applying an input from the input unit to a load, charging a secondary battery with the power from the input unit as an input, and supplying a current from the input unit to the load Is a charging device used in electronic equipment that changes depending on the load situation,
A charger that charges the secondary battery using power from the input unit as an input,
By determining whether the current output from the power supply has reached a predetermined value in accordance with power input information sensed by power input sensing means for sensing power input from the input unit, A charge control circuit that controls a charger so as to change a charging current applied to the battery so that the sum of the current applied to the load and the charging current does not exceed the predetermined value.
Characteristic charging device. An input unit for inputting electric power from a power supply, wherein the input from the input unit is for supplying power to a load and a secondary battery. In the charge control circuit for
The current supplied from the input unit to the load changes in accordance with the state of the load, and the power supply from the power supply according to power input information sensed by power input sensing means for sensing power input from the input unit. By determining whether the output current has reached a predetermined value, the charging current given to the secondary battery by the charger is changed, and the sum of the current given to the load and the charging current becomes the predetermined value. Having charge control means for controlling the charger so as not to exceed the value,
Characteristic charge control circuit.   Means for controlling the charging current such that the charging current is equal to or less than a value specified for the secondary battery in accordance with the charging current detected by the charging current detection means for detecting the charging current of the secondary battery. 21. The charge control circuit according to claim 20, further comprising:   The apparatus further comprises means for controlling a charging voltage such that a voltage detected by the charging voltage detecting means for detecting a charging voltage of the secondary battery is equal to or less than a value specified for the secondary battery. A charge control circuit according to claim 20.   23. The charging control circuit according to claim 20, wherein the predetermined value is a maximum supply power of the power supply.

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