JP3187338B2 - Battery level monitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining amount monitoring device for monitoring the amount of power charged in a battery mounted on an electronic device such as a portable personal computer, that is, the remaining amount of the battery.

[0002]

2. Description of the Related Art In a portable electronic device, if the amount of power stored in a battery as a power source, that is, the remaining battery power becomes small, a predetermined voltage cannot be obtained, and the device may become unusable. For this reason, in order to notify a user in advance that the remaining battery level is low, a device for monitoring the remaining battery level has been put to practical use. This conventional device compares a terminal voltage of a battery with a predetermined reference voltage, and determines that the remaining battery level is low (low battery state) when the terminal voltage becomes equal to or lower than the reference voltage. Has been determined. The reference voltage is set slightly higher than the voltage at which the device cannot be used, so that the user can replace the battery with a margin.

[0003]

In the above-mentioned conventional device, the reference voltage to be compared with the battery terminal voltage is a fixed value. On the other hand, since the terminal voltage of the battery changes depending on the use condition, when the reference voltage is a fixed value, there is a problem that it is determined that the remaining amount is small even though the battery is still sufficiently usable. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it is possible to change a reference voltage to be compared with a battery terminal voltage so that the remaining battery capacity can cope with a battery terminal voltage that changes depending on a use condition. It is an object to provide a monitoring device.

[0005]

A battery remaining amount monitoring device according to the present invention is a battery remaining amount monitoring device for monitoring the amount of power stored in a battery based on terminal voltages of a plurality of batteries. Terminal voltage detection means for detecting a terminal voltage, usage state determination means for determining a current battery usage state, reference voltage value setting means for setting a predetermined reference voltage value corresponding to the usage state of the battery, comparing the terminal voltage and the set reference voltage value, have a, and determining a low-battery judgment means a decrease in the remaining battery capacity when the terminal voltage becomes lower than the reference voltage value, the further <br/>, before Symbol usage determination means is adapted to determine the battery and the number thereof is used among the plurality of battery, the reference voltage value, as a battery to be monitored is in use And whether there are those set based on the number of batteries in the use.

[0006]

[0007]

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

[0009] Figure 1 is a diagram showing a basic <br/> configuration of battery-remaining amount monitoring device. The battery 1 is connected to a power supply target, that is, a load 2 which is various circuits such as electronic devices. The battery 1 is also connected to an A / D converter 3 that converts a terminal voltage of the battery from an analog value to a digital value. Therefore, this A / D converter 3
Function as terminal voltage detecting means for detecting the terminal voltage of the battery. The output of the A / D converter 3 is connected to a comparison circuit 4, and the comparison circuit 4 is further connected to a register 5. The comparison circuit 4 stores the output of the A / D converter 3 and the register 5. And compare the value to The register 5 stores a reference voltage value used to determine the amount of power stored in the battery, and this reference voltage value can be set from the outside. Therefore, the register 5 functions as a reference voltage value storage unit that can be set from the outside.
When the output of the A / D converter 3 is less than the reference voltage value of the register 5, the comparison circuit 4 operates in a state where the amount of power stored in the battery 1, that is, the remaining battery level is low (low battery state). It is determined that there is. Therefore, the comparison circuit 4 functions as a low battery determination unit. When the low battery state is determined, this is notified to the user by a predetermined method, and the user recognizes that the electronic device will not be able to be used due to the shortage of the battery. The notification of the low battery state may be visually notified by a light emitting diode (LED) or a liquid crystal, or may be notified audibly by a buzzer or the like.

According to this configuration, it is possible to change the battery voltage for notifying the low battery state without changing the components. For example, when using different types of batteries, such as a change in terminal voltage with respect to a change in remaining battery power, changing the setting of the reference voltage value,
Low battery determination according to the battery used can be performed.

[0011] Figure 2 is a diagram showing a schematic configuration of a remaining battery capacity monitoring device in the form status of the present invention. The device according to this embodiment includes two batteries, a first battery 11 and a second battery 12.
This is a case where a load 13 such as a predetermined circuit of an electronic device is driven by the individual batteries. The first battery 11 and the second battery 12 are connected to a switch 16 via diodes 14 and 15, respectively.
3 is connected. The switch 16 is configured to control the two batteries 11, 1 based on a command from a central processing unit (CPU) 17.
2 has a function of connecting one or both of them to the load 13. When the difference between the voltages of the two batteries 11 and 12 is large, the CPU 17 loads the battery with the higher voltage into the load 1.
3 and instructs the switch 16 to connect both batteries to the load 13 if the voltage difference is not very large.

The first and second batteries 11 and 12 include:
Furthermore, A / D converters 18 and 19 are connected to each other. Here, the voltage values of the batteries 11 and 12 are converted into digital values and sent to the CPU 17. Therefore, the A / D converters 18 and 19 function as terminal voltage detecting means for detecting the terminal voltage of the battery. The terminal voltages of the first and second batteries 11 and 12 detected by the A / D converters 18 and 19 correspond to the first and second registers 20 and 21 in the CPU 17.
The voltage value R1 of the battery 11 and the battery 12
Is stored as the voltage value R2. The above-described instruction of the CPU 17 to the switch 16 is performed based on the stored battery voltage values R1 and R2. That is, when the difference between the voltage values R1 and R2 is large, only the battery showing the high voltage value is connected to the load 13, and when the difference between them is not so large, both batteries are connected to the load 13. Give instructions to

The CPU 17 further calculates the two voltage values R
1, R2, and the first, second, and third set voltage values M that are predetermined and stored in the nonvolatile memory 22.
1, M2, and M3, and the reference voltage values RM1, RM are stored in the third and fourth registers 23, 24 in the CPU 17.
Stored as 2. The first set voltage value M1 is a value used for monitoring the remaining amount of the used battery when only one battery is used, and the second set voltage value M2 is the unused battery when only one battery is used. This is a value used for monitoring the remaining amount. Further, the third set voltage value M3 is a value used for monitoring the remaining amount of both batteries when both batteries are used. The reason why these plural set values are prepared is to cope with the fact that even if the remaining battery power is the same, the terminal voltage changes depending on the use condition. That is,
This is based on the fact that when a battery is used and a large current is flowing, the terminal voltage is low, and when the battery is not used, the terminal voltage is high when no current is flowing. Therefore, the first set voltage value M1 used for monitoring the used battery is a relatively low value, and the second set voltage value M2 used for monitoring the unused battery is a relatively high value. The third set voltage value M3 is an intermediate value.

The reference voltage value RM1 stored in the third register 23 is a reference voltage value for the first battery terminal voltage R1 stored in the first register 20, and the reference voltage value RM2 stored in the fourth register 24 is , The second register 2
1 is a reference voltage value for the second battery terminal voltage R2 stored in the “1”. As described above, based on the two battery terminal voltages R1 and R2, the CPU 17 uses the current battery usage status, that is, whether both batteries are used or only one battery is used. It functions as a usage status determining means for determining which battery is used. Further, the CPU 17 also functions as a reference voltage value setting unit that reads a predetermined voltage value from the nonvolatile memory 22 in accordance with the above-described use situation and sets the reference voltage value as a reference voltage value, together with the nonvolatile memory 22.

The CPU 17 controls the first battery 11
Is compared with the reference voltage value RM1, and when the terminal voltage R1 is lower than the reference voltage value RM1, the first LED 26 is turned on to notify that the first battery 11 has entered the low battery state. Further, the terminal voltage R2 is similarly compared with the reference voltage value RM2 for the second battery 12, and if the terminal voltage R2 is lower than the reference voltage value RM2,
27 is turned on to notify that the second battery 12 has entered the low battery state. Further, the CPU 17
When both the battery and the second battery are in the low battery state, the buzzer 25 further generates a warning sound,
The remaining amount of each of the two batteries is low, and the user is notified that this device will not be able to operate due to a voltage drop soon. Accordingly, the CPU 17 functions as a low battery determination unit that compares the terminal voltage of the battery with the set reference voltage, and determines a decrease in the remaining battery level when the terminal voltage falls below the reference voltage. Further, a buzzer 25, an LED 26,
27 and a circuit for driving them function as a notifying means for notifying the user of the low battery state based on the low battery determination of the CPU 17. Note that the notification by the buzzer 25 can also be performed when only one of the batteries is in the low battery state. Alternatively, the low battery state may be notified by only one of the buzzer 25 and the LEDs 26 and 27. Further, the means for giving an auditory notification is not limited to the buzzer 25, and it is also possible to provide a notification by voice from a speaker, for example. In addition, as means for visually notifying, L
Not limited to the EDs 26 and 27, for example, it can be performed by a liquid crystal display.

The above-described operations of the CPU 17 are performed based on information stored in a read-only memory (ROM) 28 connected thereto.

FIG. 3 is a flowchart showing the operation of the battery level monitoring device shown in FIG. The operation of the present apparatus will be described according to this flowchart. First, the first battery 11 converted to a digital value by the A / D converter 18
Is stored in the first register 20 (S1).
00). Similarly, the terminal voltage R2 of the second battery 12 converted into a digital value by the A / D converter 19 is equal to the second voltage.
The data is stored in the register 21 (S101).

Next, the remaining amount of the first battery 11 is checked. The terminal voltages R1, R of the two batteries 11, 12
Are compared, and when the terminal voltage R1 is sufficiently higher than the terminal voltage R2 (R1 >> R2) (S102), the first set voltage value M1 stored in the non-volatile memory 22 is read out and read. It is stored in the third register 23 (S10
3). In the case of (R1 >> R2), only the first battery 11 is connected to the load 13 by the switch 16 as described above, that is, only the first battery 11 is in use. Therefore, a large current flows through the first battery 11, so that the voltage drop becomes large and the terminal voltage becomes relatively low. Therefore, the first set voltage value M1 corresponding to this situation is selected as the reference voltage value RM1 for the first battery 11.

In step S102, (R1 >> R
2) If it is determined that this is not the case, the terminal voltage R2
Is sufficiently larger than the terminal voltage R1 (R1 << R
2) is determined (S104), and when (R1 << R2), the second set voltage value M stored in the nonvolatile memory 22 is determined.
2 is read out and stored in the third register 23 (S
105). When (R1 << R2), only the second battery 12 is in use, and the first battery 11 is not in use. Therefore, only a small current for terminal voltage detection flows in the first battery 11, and the terminal voltage becomes relatively high. Therefore, a second suitable for this situation
The set voltage value M2 is selected as the reference voltage value RM1 for the first battery 11.

Furthermore, if neither of steps S102 and S104, ie, (R1 >> R2), (R1
1 << R2), the two batteries 11, 1
2 is a case where power is supplied to the load 13 from both of them. In this case, the current flowing through the two batteries 11 and 12 has an intermediate value, and the terminal voltage at this time also has an intermediate value. Therefore, the third set voltage value M3 suitable for this situation is selected as the reference voltage value RM1 for the first battery 11 (S106).

Then, the first battery terminal voltage R1 is compared with the set reference voltage value RM1 (S107).
When the battery terminal voltage R1 becomes lower than the reference voltage value RM1, the first LED 26 is turned on, and the low battery state of the first battery 11 is notified (S108). Step S
At 107, the first battery terminal voltage R1 becomes the reference voltage value RM1.
If not, step S108 is skipped and the process proceeds to the next step.

Subsequently, the remaining amount of the second battery 12 is confirmed in the same manner as the first battery 11. That is, the terminal voltages R1 and R2 are compared, and the terminal voltage R2 is changed to the terminal voltage R1.
(R2 >> R1) when (S1
09), the first set voltage value M1 stored in the non-volatile memory 22 is read and stored in the fourth register 24 (S110). At this time (R2 >> R1), only the second battery 12 is in use. Therefore,
The terminal voltage of the second battery 12 becomes relatively low, and the first set voltage value M1 corresponding to this situation becomes the second battery 1
2 as the reference voltage value RM2.

In step S109, (R2 >> R
If it is determined that 1) is not the case, the terminal voltage R1
Is sufficiently larger than the terminal voltage R2 (R2 << R
1) is determined (S111), and when (R2 << R1), the second set voltage value M stored in the nonvolatile memory 22 is determined.
2 is read out and stored in the fourth register 24 (S
112). At this time, only the first battery 11 is in use, and the second battery 12 is not in use. Therefore, only a small current for terminal voltage detection flows in the second battery 12, and the terminal voltage becomes relatively high. Therefore, the second set voltage value M2 suitable for this situation is selected as the reference voltage value RM2 for the second battery 12.

Further, if neither of steps S109 and S111, ie, (R2 >> R1), (R2
2 << R1), the two batteries 11, 1
2 is a case where power is supplied to the load 13 from both of them. In this case, the current flowing through the two batteries 11 and 12 has an intermediate value, and the terminal voltage at this time also has an intermediate value. Therefore, the third set voltage value M3 suitable for this situation is selected as the reference voltage value RM2 for the second battery 12 (S113).

Then, the second battery terminal voltage R2 is compared with the set reference voltage value RM2 (S114).
When the battery terminal voltage R2 becomes lower than the reference voltage value RM2, the second LED 27 is turned on, and the low battery state of the second battery 12 is notified (S115). Step S
At 114, the second battery terminal voltage R2 becomes equal to the reference voltage value RM2.
If not, step S115 is skipped and the process proceeds to the next step.

Finally, the overall remaining battery level is checked. The CPU 17 includes first and second registers 20 and 2
1 and the terminal voltages R1 and R2 stored in the third and fourth terminals.
Reference voltage values RM1, R stored in registers 23, 24
M2 is compared with each other. R1 is less than RM1 and R
If 2 is less than RM2, a beep sound is generated from the buzzer 25 (S117), and the remaining amount becomes small even when the two batteries 11 and 12 are combined, so that sufficient electric power to drive this device will be soon. Foretell that it will not be obtained. If it is determined in step S116 that the terminal voltage addition value is not less than the reference voltage value addition value, step S117 is skipped and the process proceeds to the next step.

Upon completion of the above, the process returns to step S110 after a lapse of a predetermined time (S110).

[0028] According to the shape condition of the present invention, in the electronic apparatus including the two batteries, the remaining battery capacity in accordance with the case of the case, using either the use of both of the two batteries The setting of the reference voltage value for monitoring is changed. In particular, when one of the batteries is used, a reference voltage value for monitoring the remaining amount is set for each of the used battery and the unused battery.

[0029] While the form status of this embodiment, the battery mounted in the electronic device according to this device but was related to the case of the two, it can be further equipped with a number of batteries. For example, when three batteries are mounted, when only one of the three batteries is used, when two batteries are used, and when all three batteries are used, the reference voltage values for monitoring the remaining amount of the used batteries are total. It is also possible to preset three kinds of reference voltage values, which are obtained by adding three kinds of reference voltage values for monitoring the remaining amount of the unused battery, and to monitor the remaining amount. From the above, it can be understood that, when N batteries are provided, setting the reference voltage value to (N + 1) types can cope with all use situations.

[0030]

Effects of the Invention According to the present invention, to set the reference voltage value matching the current usage, by comparing the reference voltage value and the terminal voltage value, determines a low-battery condition based on usage be able to. In particular, in consideration of the fact that the terminal voltage decreases during use of the battery, the reference voltage for the used battery is set relatively low, and it is determined that the battery is in the low battery state even if the terminal voltage is detected slightly lower. Is preventing that . The usage state indicates a used battery and the number of batteries among a plurality of batteries. When the number of batteries used at the same time increases, the current flowing through each battery decreases and the decrease in terminal voltage decreases, so the reference voltage value is set accordingly. That is, the reference voltage value for the used battery and the reference voltage value for the unused battery can be set for each used number. Thus, the determination of the low battery state corresponding to the used number and the use / non-use is performed, and the determination of the low battery state despite the remaining battery level is prevented.

[0031]

[Brief description of the drawings]

FIG. 1 is a basic block diagram of a battery-remaining amount monitoring device.

2 is a schematic configuration diagram of a battery remaining capacity monitoring device showing the shape condition of the present invention.

3 is a flowchart showing the operation of the device in the form status of implementation.

[Description of Signs] 1 1,12 Battery , 13 Load , 18 , 19 A /
D converter (terminal voltage detecting means) , 17 CPU (usage state determining means, reference voltage value setting means, low battery determining means), 22 non-volatile memory (reference voltage value setting means).

Claims (1)

(57) [Claims] 1. A battery remaining amount monitoring device for monitoring an amount of electric power stored in a battery based on terminal voltages of a plurality of batteries, comprising: terminal voltage detecting means for detecting a terminal voltage of the battery; Usage status determination means for determining a status; reference voltage value setting means for setting a predetermined reference voltage value corresponding to the usage status of the battery; comparing the terminal voltage with the set reference voltage value; have a, and determining a low-battery determination means for low battery when the voltage becomes lower than the reference voltage value, the usage determining unit, of use of the plurality of battery
The battery used and its number are determined.
And the reference voltage value is the value of the battery being monitored being used.
The number of batteries in use.
A battery remaining amount monitoring device which is set based on the remaining amount.