JP6679343B2 - Wireless power transmission device, power transmission control circuit, charger - Google Patents

Description

  The present invention relates to wireless power feeding technology, and more particularly, to detecting abnormality in a wireless power transmission device.

  In recent years, wireless power supply has shown signs of widespread use as a power supply method for electronic devices. There are two types of wireless power supply, an electromagnetic induction (MI: Magnetic Induction) method and a magnetic resonance (MR: Magnetic Resonance) method. In the MI method, (1) WPC (Wireless Power Consortium) is currently established. The standard "Qi" and (2) PMA (Power Matters Alliance) standard (hereinafter referred to as PMA) are the mainstream.

  The MI type wireless power supply utilizes electromagnetic induction between a transmitting coil and a receiving coil. The power feeding system includes a power transmitting device having a transmitting coil and a power receiving device having a receiving coil.

  FIG. 1 is a diagram showing a configuration of a wireless power supply system 10 based on the Qi standard. The power feeding system 10 includes a power transmitting device 20 (TX, Power Transmitter) and a power receiving device 30 (RX, Power Receiver). The power receiving device 30 is mounted on an electronic device such as a mobile phone terminal, a smart phone, an audio player, a game device, and a tablet terminal.

  The power transmission device 20 includes a transmission coil (primary coil) 22, a driver 24, a power transmission controller 26, and a demodulator 28. The driver 24 includes an H-bridge circuit (full-bridge circuit) or a half-bridge circuit, applies a drive signal S1, specifically a pulse signal, to the transmission coil 22 and causes the transmission coil 22 to receive a drive current. An electromagnetic field power signal S2 is generated. The power transmission controller 26 controls the power transmission device 20 as a whole, and specifically controls the switching frequency, the switching duty ratio, the phase, and the like of the driver 24 to change the transmission power.

  The power receiving device 30 includes a receiving coil (secondary coil) 32, a rectifying circuit 34, a smoothing capacitor 36, a modulator 38, a load 40, a power receiving controller 42, and a power supply circuit 44. The receiving coil 32 receives the power signal S2 from the transmitting coil 22. The rectifier circuit 34 and the smoothing capacitor 36 rectify and smooth the current S4 induced in the receiving coil 32 according to the power signal S2, and convert it into a DC voltage.

The power supply circuit 44 uses a power supplied from the power transmission device 20 to charge a secondary battery (not shown) or steps up or steps down the DC voltage V _RECT and supplies the power reception controller 42 and other loads 40.

  In the Qi standard, a communication protocol is defined between the power transmitting device 20 and the power receiving device 30, and information can be transmitted from the power receiving device 30 to the power transmitting device 20 by the control signal S3. The control signal S3 is transmitted from the reception coil 32 (secondary coil) to the transmission coil 22 in a form of AM (Amplitude Modulation) modulation using backscatter modulation. The control signal S3 includes, for example, power control data (also referred to as a packet) that controls the amount of power supplied to the power receiving device 30 and data indicating information unique to the power receiving device 30.

The power control will be described. The power reception controller 42 of the power reception device 30 generates power control data that controls the amount of power supplied from the power transmission device 20 (transmission power). For example, the power reception controller 42 generates a power control packet so that the voltage V _RECT of the smoothing capacitor 36 approaches its target value (DP: Desired Point). The modulator 38 modulates the current (or voltage) of the receiving coil 32 based on the power control packet. As a result, the receiving coil 32 serves as a transmitting antenna, and the control signal S3 is transmitted.

  In the power transmission device 20, a current component according to the control signal S3 flows through the transmission coil 22. The demodulator 28 demodulates the control signal S3 included in the current or voltage of the transmission coil 22. The power transmission controller 26 controls the driver 24 so that the transmission power instructed by the power control data included in the demodulated control signal S3 is obtained.

  In this way, in the power supply system 10 conforming to the Qi standard, the transmission power is feedback-controlled so as to match the power required by the power receiving device side.

FIG. 2 is a circuit diagram showing a configuration example of the power transmission device 20. The current sensor 206 detects the current I _IN flowing through the driver 24 and generates a current detection (ISENSE) signal indicating the amount of current. The current sensor 206 includes a sense resistor R _S and a sense amplifier 207. The sense resistor R _S is inserted in the current path of the driver 24, and a voltage drop V _S proportional to the input current I _IN of the driver 24 is generated across the sense resistor R _S. The sense amplifier 207 amplifies the voltage drop V _S across the sense resistor R _S and generates an ISENSE signal. The ISENSE signal is input to the power transmission controller 26 and used for various processes.

  For example, the ISENSE signal is used for overcurrent protection. When the ISENSE signal exceeds a predetermined threshold value, the power transmission controller 26 determines an overcurrent state and executes a predetermined protection process. The ISENSE signal is used for FOD (Foreign Object Detection) by the power loss method.

The input voltage V _IN is input to the power transmission controller 26 together with the ISENSE signal. The ISENSE signal and the input voltage V _IN are converted into digital values by the A / D converter of the power transmission controller 26. The power transmission controller 26 calculates the product of the input current I _IN and the input voltage V _IN to obtain the transmission power P _TX . Alternatively, the ISENSE signal can be used for the measurement of the Q value and the detection of foreign matter based on the Q value.

JP, 2013-38854, A Japanese Patent No. 5071574

The power transmission device 20 in FIG. 2 includes various circuit components such as a driver 24, a high-side switch SW1, a sense resistor R _S , and a transmission coil 22 in addition to the power transmission controller 26. In order to safely transmit power from the power transmission device 20, all components must be properly mounted and function properly. In particular, power transmission is performed in a state where an abnormality has occurred in a component (referred to as a power line) from the high side switch SW1 to the ground via the sense resistor R _S , the driver 24, the transmission coil 22, the resonance capacitor 23, and the driver 24. If started, it may cause abnormal heat generation and decrease in reliability of circuit components.

  Particularly in recent years, the development of the Qi standard (Power Class 0 Extended Power Profile) for medium power has been promoted, the transmission power tends to increase, and the safety function is becoming more important.

  The present invention has been made in view of the above problems, and one of the exemplary objects of a certain aspect thereof is to provide a power transmission device with improved safety and reliability.

  One aspect of the present invention relates to a wireless power transmitting apparatus that transmits a power signal to a wireless power receiving apparatus. The wireless power transmission device includes a sub power supply circuit that generates a second voltage lower than the first voltage, a transmission antenna that includes a resonance capacitor and a transmission coil that are connected in series, and a driver that includes a bridge circuit that applies a drive voltage to the transmission antenna. And a high-side switch that selects one of the first voltage and the second voltage and supplies it to the upper power supply terminal of the driver.

  According to this aspect, it is possible to perform a test operation in which the driver performs the switching operation in the state where the second voltage lower than the regular first voltage is selected. By detecting various abnormalities during the trial run, safety and reliability can be improved. Further, even if there is an abnormality in the circuit, the operating voltage during the trial run is low, so heat generation and overcurrent can be suppressed, and safety and reliability can be further enhanced.

  The power transmission control circuit may monitor the electrical state of the transmitting antenna when the high-side switch selects the second voltage. Thereby, the abnormality of the driver or the transmitting antenna can be safely determined.

  The power transmission control circuit sweeps the switching frequency of the driver in the state where the high-side switch selects the second voltage and determines whether the resonance frequency of the transmission antenna is abnormal based on the electrical state of the transmission antenna at that time. Good. Thereby, the abnormality of the transmitting antenna can be safely judged.

  A wireless power transmission device of an aspect includes a current sensor including a sense resistor provided on a path of a current flowing through a bridge circuit, a bias circuit that can be switched on and off, and that provides a predetermined bias signal to the sense resistor in an on state. , May be further provided. Thereby, the abnormality of the sense resistor can be detected.

  The bias circuit may include a constant current source. In this case, the abnormality of the sense resistor can be detected or the resistance value can be measured based on the voltage drop of the sense resistor.

  The sub power supply circuit may be integrated in the same integrated circuit as the power transmission control circuit. The sub power supply circuit may be a linear regulator.

  The wireless power transmission device may comply with at least one of the Qi standard and the PMA standard.

  Another aspect of the present invention relates to a charger. The charger may include any of the wireless power transmission devices described above.

  Another aspect of the present invention relates to a power transmission control circuit that controls a wireless power transmission device. The wireless power transmission device receives a transmission antenna including a resonance capacitor and a transmission coil connected in series, a driver including a bridge circuit for applying a driving voltage to the transmission antenna, a first voltage and a second voltage lower than the first voltage. A high-side switch having two input terminals, an output terminal connected to the upper power supply terminal of the driver, and a current sensor including a sense resistor provided on the path of the current flowing through the bridge circuit are provided. The power transmission control circuit includes a demodulator that demodulates the control signal received by the transmission antenna, a power controller and a pre-driver that control the driver based on the control signal, a sub power supply circuit that generates a second voltage, and a high-side switch. A switch driver to be controlled, and a logic unit that detects an abnormality of the wireless power transmission device by performing a test operation in which the high-side switch selects the second voltage and the driver switches in the self-diagnosis sequence before the start of power supply.

  According to this aspect, the self-diagnosis sequence for performing various abnormality detections is executed during the test operation in which the second voltage lower than the regular first voltage is operated, so that even if there is an abnormality in the circuit, the heat generation is generated. And overcurrent can be suppressed, and safety can be improved.

  The logic unit may detect the abnormality of the driver and the transmission antenna based on the electrical state of the transmission antenna during the trial run.

  The logic unit may sweep the switching frequency of the driver during the test operation, and detect an abnormality in the resonance frequency of the transmission antenna based on the electrical state of the transmission antenna at that time.

  The power transmission control circuit according to an aspect may be switched between on and off, and may further include a bias circuit that applies a predetermined bias signal to the sense resistor in the on state. The logic unit may turn on the bias circuit with the driver stopped, and detect the abnormality of the sense resistor based on the electrical state of the sense resistor at that time. The bias circuit may include a constant current source.

The power transmission control circuit may be integrated on a single semiconductor substrate.
"Integrated integration" includes the case where all the components of the circuit are formed on the semiconductor substrate and the case where the main components of the circuit are integrated, and some of them are used for adjusting the circuit constants. A resistor or a capacitor may be provided outside the semiconductor substrate.
By integrating the circuit on one chip, the circuit area can be reduced and the characteristics of the circuit element can be kept uniform.

  It should be noted that any combination of the above constituent elements, and those in which the constituent elements and expressions of the present invention are mutually replaced among methods, devices, systems, etc. are also effective as an aspect of the present invention.

  According to an aspect of the present invention, it is possible to provide a power transmission device having a self-diagnosis function of abnormality.

It is a figure which shows the structure of the wireless power supply system based on Qi standard. It is a circuit diagram which shows the structural example of a power transmission device. It is a block diagram of the electric power feeding system provided with the wireless power transmission device which concerns on embodiment. 4 is a flowchart showing a sequence of self-diagnosis by the power transmission device of FIG. 3. It is a figure which shows the specific structural example of the power transmission apparatus of FIG. It is a circuit diagram of a charger provided with a power transmission device.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and duplicated description will be appropriately omitted. Further, the embodiments are examples that do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In the present specification, "the state in which the member A is connected to the member B" means that the members A and B are electrically connected in addition to the case where the members A and B are physically directly connected. It also includes the case of being indirectly connected via another member that does not substantially affect the general connection state or does not impair the function or effect achieved by their connection.
Similarly, "the state in which the member C is provided between the member A and the member B" means that the members A and C or the members B and C are directly connected to each other and their electrical It also includes the case of being indirectly connected via another member that does not substantially affect the general connection state or does not impair the function or effect achieved by their connection.

  FIG. 3 is a block diagram of a power supply system 100 including the wireless power transmission device 200 according to the embodiment. The power feeding system 100 includes a power transmitting device 200 and a power receiving device 300. The power receiving device 300 is mounted on an electronic device such as a mobile phone terminal, a smart phone, an audio player, a game device, and a tablet terminal. The power transmission device 200 complies with at least one of the Qi standard and the PMA standard. In the present embodiment, the configuration and operation will be described based on the Qi standard.

  Power transmission device 200 is mounted on, for example, a charger having a charging stand. The power transmission device 200 includes a transmission antenna 201, a driver 204, a current sensor 206, a high side switch SW2, a DC / DC converter 210, and a power transmission control circuit (hereinafter, TX controller) 600.

The power transmission device 200 receives a DC input voltage (referred to as a first voltage) V _IN at an input terminal P _IN . The first voltage V _IN is a regular voltage used during power transmission, and varies from 5V, 12V, and 20V depending on the standard. The first voltage V _IN is input to the A terminal of the high side switch SW2.

The transmission antenna 201 includes a transmission coil 202 and a resonance capacitor 203 which are connected in series. The driver 204 includes an H-bridge circuit (full-bridge circuit) or a half-bridge circuit, applies a drive signal S1, specifically a pulse signal, to the transmission coil 202, and applies a drive current to the transmission coil 202 so that the transmission coil 202 receives the drive signal S1. An electromagnetic field power signal S2 is generated. In this embodiment, a full bridge circuit is used. During power transmission to the power receiving device 300, the first voltage V _IN is supplied to the upper power supply terminal P1 of the bridge circuit 205 and the lower power supply terminal P2 is grounded. The smoothing capacitor C _S may be connected to the upper power supply terminal P1.

  The TX controller 600 is a circuit block that controls the entire power transmission device 200 as a whole, and may be an IC integrated on one semiconductor substrate, or may be a combination of a plurality of ICs and chip parts. Good.

Specifically, the TX controller 600 controls the switching frequency f _SW of the bridge circuit 205, the switching duty ratio, the operation mode (half bridge mode / full bridge mode), or the phase difference between the legs in the full bridge mode. , Change the transmission power.

  In the Qi standard, a communication protocol is defined between the power transmitting device 200 and the power receiving device 300, and information can be transmitted from the power receiving device to the power transmitting device 200 by the control signal S3. The control signal S3 is transmitted from the reception coil 302 (secondary coil) to the transmission coil 202 in a form of AM (Amplitude Modulation) modulation using backscatter modulation. The control signal S3 includes, for example, power control data (also referred to as a packet) that controls the amount of power supplied to the power receiving device 300, data indicating information unique to the power receiving device 300, and the like. Further, the control signal S3 may include a threshold value that defines an appropriate range of the Q value of the transmitting antenna 201.

  The TX controller 600 receives a signal according to the coil current or the coil voltage at the demodulation terminal (DEMOD) and demodulates the control signal S3 included in the current or the voltage of the transmission coil 202. The TX controller 600 controls the driver 204 based on the power control data included in the demodulated control signal S3.

The current sensor 206 is provided to detect foreign matter and protect against overcurrent. The current sensor 206 detects the current I _IN flowing through the driver 24 and generates a current detection (ISENSE) signal indicating the amount of current. The current sensor 206 may include a sense resistor R _S and a sense amplifier 207. The ISENSE signal is input to the ISENSE terminal of the TX controller 600. The TX controller 600 performs foreign object detection or overcurrent protection based on the ISENSE signal.

The DC / DC converter 210 receives the first voltage V _IN , steps it down, and generates the power supply voltage V _CC of the TX controller 600.

  The power transmission device 200 according to the embodiment has a function (hereinafter, referred to as a self-diagnosis function) of diagnosing whether the power transmission device 200 itself is normal before starting power transmission. Hereinafter, the self-diagnosis function of the power transmission device 200 will be described.

Regarding the self-diagnosis function, the power transmission device 200 includes a sub power supply circuit 602. The sub power supply circuit 602 may be built in the TX controller 600 or may be an external power supply circuit like the DC / DC converter 210. Sub power circuit 602 on the basis of the first voltage _{V IN,} and generates a second voltage _{V LOW} lower DC than the first voltage _{V IN.} The second voltage V _LOW is preferably lower than 5V, and may be, for example, 2-3V, specifically 2.5V. Alternatively, the second voltage V _LOW may be set to 1 V or less, or may be set to about 0.1 to 0.4 V, in order to further enhance the safety during the test operation described later.

For example, the sub power supply circuit 602 is an LDO (Low Drop Output), that is, a linear regulator that receives the power supply voltage V _CC generated by the DC / DC converter 210 and generates the second voltage V _LOW stabilized at a predetermined level. May be. Alternatively, the sub power supply circuit 602 may be a step-down DC / DC converter that steps down the input voltage V _IN and generates the second voltage V _LOW .

The second voltage V _LOW is input to the B terminal of the high side switch SW2. The high-side switch SW2 is turned on to either the A terminal or the B terminal, selects one of the first voltage V _IN and the second voltage V _LOW , and supplies it to the upper power supply terminal P1 of the driver 204. The high-side switch SW2 can also be selected in an off state in which neither the A terminal nor the B terminal is electrically connected. The high side switch SW2 can also be understood as a selector. The high-side switch SW2 is connected to the SWDRV (switch drive) terminal of the TX controller 600, and the state is switched according to the drive signal S11.

Further, the VS1 (first voltage detection) terminal of the TX controller 600 is the high-potential side voltage of the sense resistor R _S , and the VS2 (second voltage detection) terminal is the low-potential side voltage of the sense resistor R _S. Is entered. Further, the voltage at one end of the transmission coil 202 is input to the VS3 (third voltage detection) terminal of the TX controller 600. The bias (IBIAS) terminal of the TX controller 600 is connected to the low potential side line of the sense resistor R _S. The bias circuit 604 of the TX controller 600 can be switched between on and off, and can supply a known bias signal to the sense resistor R _S in the on state. For example, the bias circuit 604 includes a constant current source 606, and causes a known amount of bias current I _BIAS to flow through the sense resistor R _S.

The above is the configuration of the power transmission device 200. Next, the operation will be described.
FIG. 4 is a flowchart showing a self-diagnosis sequence by the power transmission device 200 of FIG. When the input voltage V _IN is supplied, the DC / DC converter 210 generates the power supply voltage V _CC , and the TX controller 600 is activated. The TX controller 600 executes the self-diagnosis sequence of FIG. 4 before the start of power supply to the power receiving device 300 (that is, before the transition to the Analog pin phase).

First, the TX controller 600 performs pre-abnormality determination S100. In the pre-abnormality determination S100, the high side switch SW2 is turned on to the A terminal side, and then turned off. The TX controller 600 confirms whether the power supply is normal or whether the high side switch SW2 or the sense resistor R _S is attached by monitoring the potentials of the VS1 terminal and the VS2 terminal and the potential difference between them (S100). ).

Subsequently, the TX controller 600 determines the abnormality of the sense resistor R _S (S102). Specifically, the TX controller 600 turns on the high-side switch SW2 to the A terminal side, turns on the bias circuit 604, and applies a known bias current I _BIAS to the sense resistor R _S. At this time, a voltage drop of I _BIAS × R _S occurs in the sense resistor R _S. The TX controller 600 detects whether the sense resistor R _S is normal or abnormal based on the voltage of the VS1 terminal, the VS2 terminal, and / or the voltage of the ISENSE terminal.

Subsequently, the sub power supply circuit 602 generates the second voltage V _LOW lower than the first voltage V _IN, and turns on the high side switch SW2 to the B terminal side (S104). In this state, by performing a trial run of the power transmission device 200 (S106), by any chance, a power line from the input terminal P _IN to the ground via the high side switch SW2, the sense resistor R _S , the driver 204, the transmission antenna 201, and the driver 204 is connected. Even if a short circuit failure or other abnormality occurs, overcurrent and heat generation can be suppressed as compared with the case where a large first voltage V _IN is applied to the power line.

For example, the TX controller 600 detects an abnormality in the driver 204, the transmission coil 202, and the resonance capacitor 203 by monitoring the electrical state of the transmission antenna 201 in a state in which the power transmission device 200 is test-run at a low second voltage V _LOW. You may do (S108). For example, the TX controller 600 may monitor the coil voltage or the coil current as the electrical state of the transmitting antenna 201, specifically the voltage of the VS3 terminal, or the ISENSE signal. Good. The coil voltage can be monitored by the VS3 terminal, and the coil current can be monitored based on the ISENSE signal.

  Further, a current sensor may be further provided in order to accurately detect the coil current. For example, the current sensor may detect a current flowing through a transistor included in the bridge circuit 205. A known technique may be used for the method of detecting the current flowing in the transistor. Alternatively, when the sub power supply circuit 602 includes a current sensor, the detected current value may be used as the coil current.

In addition, the TX controller 600 monitors the at least one of the coil voltage and the coil current while sweeping the switching frequency of the driver 204 in a state in which the power transmission device 200 is being trial- _operated at the low second voltage V _LOW , to thereby transmit the transmission antenna 201. You may measure the resonance frequency of (S110). The measurement result of the resonance frequency can be used for the abnormality determination of the transmitting antenna 201 and can be used for the foreign matter detection using the Q value.

  When the power transmission device 200 is determined to be normal as a result of the self-diagnosis sequence in FIG. 4, the power supply device 200 shifts to the analog ping phase and then starts power supply to the power reception device 300. If an abnormality is detected in any of the diagnoses, the high side switch SW2 may be turned off to immediately stop the operation of the power transmission device 200. Further, the occurrence of an abnormality and / or the cause of the abnormality may be notified to an external processor or device.

  The execution order of the self-diagnosis sequence of FIG. 4 is not limited to that of FIG. 4, and some steps may be replaced and some steps may be omitted. Furthermore, step S100 or step S102 may be executed between steps S104 and S106. This can further increase safety.

  The above is the operation of the power transmission device 200. The present invention extends to various devices and circuits understood as the block diagram and circuit diagram of FIG. 3 or derived from the above description, and is not limited to a specific configuration. Hereinafter, a more specific configuration example will be described in order to help understanding of the essence of the invention and circuit operation and to clarify them, not to narrow the scope of the invention.

  FIG. 5 is a diagram showing a specific configuration example of the power transmission device 200 of FIG.

  The demodulator 614 demodulates the control signal S3 included in the current or voltage of the transmission coil 202. The power controller 610 indicates the switching frequency of the driver 204, the duty ratio, the operation mode (half bridge / full bridge), and the phase difference between the legs in the full bridge mode based on the power control data S21 received by the demodulator 614. The control command S8 is generated. The pre-driver 612 drives the bridge circuit 205 according to the control command S8.

  An OCP (overcurrent protection) circuit 620 and an FOD (foreign matter detection) circuit 622 are provided in connection with foreign matter detection or overcurrent protection. The OCP circuit 620 compares the ISENSE signal with a predetermined threshold value to detect an overcurrent state. When the overcurrent is detected, the high side switch SW2 is switched to the off state and the operation of the driver 204 is stopped.

  The FOD circuit 622 calculates the transmission power based on the ISENSE signal. Then, the presence or absence of foreign matter is determined by the power loss method by comparison with the received power S22 included in the control signal S3 received by the demodulator 614.

  The blocks related to the above self-diagnosis function will be described. Regarding the self-diagnosis function, the power transmission device 200 includes a logic unit 630, a sub power supply circuit 602, a switch driver 632, a first voltage monitoring circuit 634, a second voltage monitoring circuit 636, and a bias circuit 604.

  The logic unit 630 is a sequencer that controls other circuit blocks in the self-diagnosis sequence. The logic unit 630 is a determiner that determines whether or not there is an abnormality in each circuit element on the power line based on the monitoring results of the first voltage monitoring circuit 634 and the second voltage monitoring circuit 636. Further, the logic unit 630 is also responsible for sequence control related to normal power supply, and based on the control signal S23 received by the demodulator 614, a ping (Ping) phase, an authentication / configuration (Identification & configuration) phase, and power transfer (Power Transfer). ) Perform various phase controls.

  The switch driver 632 switches the state of the high side switch SW2 based on the selection signal S12 from the logic unit 630.

The first voltage monitoring circuit 634 monitors the voltage of each terminal of the sense resistor R _S and the potential difference between them. The second voltage monitoring circuit 636 monitors the voltage of the transmission coil 202. The first voltage monitoring circuit 634 and the second voltage monitoring circuit 636 may include an A / D converter.

  Next, the usage of the power transmission device 200 will be described. FIG. 6 is a circuit diagram of a charger 400 including the power transmission device 200. The charger 400 charges an electronic device including the power receiving device 300. The charger 400 includes a housing 402, a charging stand 404, and a circuit board 406. The charger 400 may be a vehicle-mounted charger. The electronic device to be supplied with power is placed on the charging stand 404. The driver 204, the TX controller 600, and other circuit components are mounted on the circuit board 406. The transmitting antenna 201 is laid out immediately below the charging stand 404. Charger 400 may receive a DC voltage by AC / DC converter 410, or may have an AC / DC converter built therein. Alternatively, the charger 400 may be supplied with DC power from the outside via a bus including a power supply line such as a USB (Universal Serial Bus).

  It is understood by those skilled in the art that the embodiments are exemplifications, that various modifications can be made to the combinations of their respective constituent elements and respective processing processes, and that such modifications are also within the scope of the present invention. . Hereinafter, such modified examples will be described.

(First modification)
The bias circuit 604 may include a resistance element having a known resistance value and a switch connected in series with the resistance element, instead of the constant current source 606.

(Second modified example)
In the embodiment, the driver 204 of the H-bridge circuit has been described, but it can be applied to the half-bridge circuit.

  Although the present invention has been described using specific terms based on the embodiments, the embodiments merely show the principle and application of the present invention, and the embodiments are defined in the claims. Many modifications and changes in arrangement are possible without departing from the concept of the present invention.

100 ... Power feeding system, 200 ... Power transmission device, 201 ... Transmission antenna, 202 ... Transmission coil, 203 ... Resonance capacitor, 204 ... Driver, 205 ... Bridge circuit, 206 ... Current sensor, _RS ... Sense resistor, 207 ... Sense amplifier, 210 ... DC / DC converter, SW2 ... High side switch, 600 ... TX controller, 602 ... Sub power supply circuit, 604 ... Bias circuit, 606 ... Constant current source, 610 ... Power controller, 612 ... Pre-driver, 614 ... Demodulator, 620 ... OCP circuit, 622 ... FOD circuit, 630 ... Logic part, 632 ... Switch driver, 634 ... First voltage monitoring circuit, 636 ... Second voltage monitoring circuit, 300 ... Power receiving device, 302 ... Reception coil, 600 ... TX controller , 610 ... Power controller, 612 ... Pre-driver 400 ... charger, 402 ... housing, 404 ... charger, 406 ... circuit board.

Claims (13)

A wireless power transmitting device that transmits a power signal to a wireless power receiving device,
A sub power supply circuit for generating a second voltage lower than the first voltage;
A transmitting antenna including a resonant capacitor and a transmitting coil connected in series;
A driver including a bridge circuit for applying a driving voltage to the transmitting antenna,
A power transmission control circuit for controlling the driver;
A high-side switch that selects one of the first voltage and the second voltage and supplies it to the upper power supply terminal of the driver;
Bei to give a,
The power transmission control circuit monitors an electrical state of the transmitting antenna in a state where the high-side switch selects the second voltage,
The power transmission control circuit sweeps the switching frequency of the driver in the state where the high-side switch selects the second voltage, and based on the electrical state of the transmission antenna at that time, the resonance frequency of the transmission antenna A wireless power transmitting device characterized by determining abnormality . A current sensor including a sense resistor provided on a path of a current flowing through the bridge circuit,
A bias circuit that applies a predetermined bias signal to the sense resistor in a switching stopped state of the bridge circuit;
The wireless power transmission device according to claim 1 , further comprising:   A wireless power transmitting device that transmits a power signal to a wireless power receiving device,
  A sub power supply circuit for generating a second voltage lower than the first voltage;
  A transmitting antenna including a resonant capacitor and a transmitting coil connected in series;
  A driver including a bridge circuit for applying a driving voltage to the transmitting antenna,
  A power transmission control circuit for controlling the driver;
  A high-side switch that selects one of the first voltage and the second voltage and supplies it to the upper power supply terminal of the driver;
  A current sensor including a sense resistor provided on a path of a current flowing through the bridge circuit,
  A bias circuit that applies a predetermined bias signal to the sense resistor in a switching stopped state of the bridge circuit;
  A wireless power transmission device comprising: The wireless power transmitting device according to claim 2, wherein the bias circuit includes a constant current source. The sub power supply circuit, a wireless power transmission device according to any one of 4 from claim 1, characterized in that it is integrated in the power transmission control circuit in the same integrated circuit. Wireless power transmission device according to any one of claims 1-5, characterized in that conforming to at least one of Qi standard and PMA standards. Charger, characterized in that it comprises a wireless power transmission device according to any one of claims 1 to 6. A power transmission control circuit for controlling a wireless power transmission device,
The wireless power transmission device,
A transmitting antenna including a resonant capacitor and a transmitting coil connected in series;
A driver including a bridge circuit for applying a driving voltage to the transmitting antenna,
A high side switch having two input terminals for receiving a first voltage and a second voltage lower than the first voltage, and an output terminal connected to an upper power supply terminal of the driver,
A current sensor including a sense resistor provided on a path of a current flowing through the bridge circuit,
Equipped with
The power transmission control circuit,
A demodulator for demodulating the control signal received by the transmitting antenna,
A power controller and a pre-driver for controlling the driver based on the control signal;
A sub power supply circuit for generating the second voltage,
A switch driver that controls the high-side switch,
In a self-diagnosis sequence before the start of power supply, the high-side switch selects the second voltage, and performs a test operation in which the driver switches, and a logic unit that detects an abnormality of the wireless power transmission device,
A power transmission control circuit comprising: The power transmission control circuit according to claim 8 , wherein the logic unit detects an abnormality in the driver and the transmission antenna based on an electrical state of the transmission antenna during the test operation. The logic unit sweeps the switching frequency of the driver during the test operation, and detects an abnormality in the resonance frequency of the transmitting antenna based on the electrical state of the transmitting antenna at that time. The power transmission control circuit according to claim 8 . It is possible to switch on and off, and further comprising a bias circuit that applies a predetermined bias signal to the sense resistor in the on state,
The logic unit is configured to turn on the bias circuit in a state of stopping the driver, based on the electrical state of the sense resistor at that time, from claim 8, characterized in that for detecting an abnormality of the sense resistor 10. The power transmission control circuit according to any one of 10 . The power transmission control circuit according to claim 11 , wherein the bias circuit includes a constant current source. The power transmission control circuit according to claim 8 , wherein the power transmission control circuit is integrated on one semiconductor substrate.

Images