JP2008206326A - Power transmission controller, non-contact point power transmission system, power transmitter, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve safety of a non-contact point power transmission system by enabling detection of fault due to short circuit in a driver of a primary coil. <P>SOLUTION: A fault detecting circuit (34) monitors a voltage of one end of the primary coil (L1), thereby detecting faults of transistors (M1 and M2, and M3 and M4) constituting power transmission drivers (13, 15). Also, initial faults of the power transmission drivers (13, 15) can be detected by providing test drivers (TE1, TE2). Voltages of coil ends (N1, N2) of the primary coil (L1) during a period of stable voltage can be detected by selecting on-timing of each of switches (SW1, SW2) provided on monitor window circuits (MWD1, MWD2). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power transmission control device, a contactless power transmission system, a power transmission device, and an electronic device.

  In recent years, contactless power transmission (contactless power transmission) that uses electromagnetic induction and enables power transmission even without a metal part contact has been highlighted. Charging of telephones and household equipment (for example, a handset of a telephone) has been proposed.

A non-contact power transmission device using a primary coil and a secondary coil is described in Patent Document 1, for example. In the non-contact power transmission system described in Patent Document 1, a CMOS configuration driver (CMOS driver) is used as a driver for driving a primary coil, and each CMOS driver is provided for preventing a through current. A control circuit (timing control circuit) is provided. The control circuit (timing control circuit) prevents the through current from flowing by preventing the PMOS transistor and the NMOS transistor from being simultaneously turned on. Prevention of a through current in the primary side driver is effective in preventing a driver failure.
Japanese Patent Laying-Open No. 2006-60909 (FIG. 3)

  In the non-contact power transmission system described in Patent Document 1, through current can be prevented by adjusting the drive timing of each transistor of the driver that drives the primary coil, but there is no short circuit failure of each transistor. No measures are taken.

  For example, if the NMOS transistor that constitutes the CMOS driver fails and cannot be completely turned off (that is, current always flows), if normal power transmission is continued without being detected, it will eventually become normal due to the through current. It cannot be said that there is no case where the PMOS transistor also fails. When both the PMOS transistor and the NMOS transistor fail, a large current flows between the power supplies, which may cause heat generation or equipment destruction.

  Further, when an initial failure occurs in a transistor constituting the CMOS driver, the initial failure is detected before normal driving, and the device is recovered and repaired without performing normal driving. And taking appropriate measures is more desirable for safety.

  The present invention has been made based on such considerations, and an object thereof is to enable detection of a short-circuit fault of a driver of a primary coil and improve safety of a contactless power transmission system.

  (1) In one aspect of the power transmission control device of the present invention, the primary coil and the secondary coil are electromagnetically coupled to transmit power from the power transmission device to the power receiving device, and to the main load of the power receiving device. A power transmission control device provided in the power transmission device of a contactless power transmission system that supplies power, the power transmission device including a first power transmission driver that drives one end of the primary coil, and the primary coil. A second power transmission driver that drives the end, the power transmission control device includes a power transmission side control circuit that controls an operation of the power transmission device, and the power transmission side control circuit includes the first coil. A failure detection circuit that detects a failure of the first power transmission driver and the second power transmission driver by monitoring a coil end voltage that is a voltage of at least one of the one end and the other end; The coil terminal Is not a coil end voltage corresponding to an input signal of the first power transmission driver or the second power transmission driver, it is determined that the first power transmission driver or the second power transmission driver has failed. .

  A failure detection circuit is provided in the power transmission device (primary device) of the non-contact power transmission system so that a short circuit failure of the driver can be detected. The failure detection circuit monitors the coil end voltage of the primary coil, and determines whether or not the driver has a coil end voltage corresponding to the input voltage of the driver (at least one of the first and second power transmission drivers). Detect a short-circuit fault. Thereby, the safety | security of a power transmission apparatus and a non-contact power transmission system can be improved.

  (2) In another aspect of the power transmission control device of the present invention, the failure detection circuit is configured such that the coil end is in a state where the first power transmission driver and the second power transmission driver normally drive the primary coil. The voltage is monitored to detect a failure of the first power transmission driver or the second power transmission driver during normal driving.

  Fault detection is performed during normal driving of the driver (during normal power transmission), and short-circuit faults that occur during normal driving (during normal power transmission) are detected early. Accordingly, for example, it is possible to quickly take appropriate measures such as stopping power transmission and notifying a failure.

  (3) In another aspect of the power transmission control device of the present invention, a first test driver that drives the one end of the primary coil and a second test driver that drives the other end of the primary coil. The power transmission side control circuit further includes the first power transmission driver or the second power transmission before the primary coil is normally driven by the first power transmission driver and the second power transmission driver. The level of each input signal of the driver is set to a level at which the one end or the other end of the primary coil is in a floating state, and in this state, the first test driver or the second test driver The one end or the other end of the primary coil is driven, and the failure detection circuit has the coil end voltage of the first test driver or the second test driver. When it is not the coil end voltage corresponding to the dynamic power level, the first power transmitting driver or the second power transmitting driver, determines that the initial failure occurs.

  Prior to normal driving, an initial failure of a power transmission driver (first and second power transmission drivers) is detected using a test driver. The input level of each transistor of the power transmission driver (first and second power transmission drivers) is adjusted to turn off all the transistors. As a result, the end of the primary coil is in a floating state. In this state, the coil end is driven by the test driver. Since the power transmission drivers (first and second power transmission drivers) are disabled, the coil end voltage is under the control of the test driver. Therefore, the coil end voltage is the drive voltage (output end voltage) of the test driver. However, if an initial failure has occurred in the power transmission driver (first and second power transmission drivers), the coil end voltage is for testing due to the leakage current of the failed transistor. It will not match the drive voltage of the driver. Therefore, an initial failure can be detected. When an initial failure is detected, for example, normal driving is disabled and the initial failure is notified. As a result, for example, it is possible to quickly take appropriate measures such as collecting and repairing the device, and safety is further improved.

  (4) In another aspect of the power transmission control device of the present invention, a first resonance capacitor and a second capacitor are connected in series to the primary coil to form a series resonance circuit. When performing failure detection, the one end and the other end of the primary coil are complementarily driven by the first test driver and the second test driver, and the failure detection circuit includes the first test driver and the second test driver. The voltage fluctuation due to the AC component flowing through the capacitor and the second capacitor is monitored, and an initial failure of the first capacitor or the second capacitor is detected depending on whether or not a predetermined voltage fluctuation is detected. .

  In the above-described aspect, the failure of the transistors constituting the power transmission driver (first and second power transmission drivers) is detected. However, in this aspect, the failure (initial failure) of the capacitor constituting the series resonance circuit together with the primary coil is detected. To detect. For example, two test drivers are operated simultaneously to change the first and second coil end voltages in a complementary manner. For example, when the voltage at the first coil end is changed from “L” to “H”, the voltage at the second coil end is changed from “H” to “L” (that is, complementary) in synchronization with this. Change. As a result, the AC component generated by the voltage change flows from the first coil to the second coil end via the first and second capacitors. Therefore, when the fluctuation of the coil end voltage due to the AC component cannot be detected, it can be determined that an initial failure has occurred in either the first or second capacitor. Therefore, the safety of the power transmission device (and contactless power transmission system) is further improved.

  (5) In another aspect of the power transmission control device of the present invention, each of the first test driver and the second test driver is connected in series between power supply voltages and has a first conductivity type different from each other. And a second transistor and a current limiting resistor.

  It is clarified that the test driver is a driver of a complementary transistor configuration including a current limiting resistor. If the current driving capability of the test driver is too high, if the leakage current of the transistor of the power transmission driver (first and second power transmission drivers) in which the initial failure occurs is small, the leakage current is masked. It cannot be said that the initial failure may not be detected. Therefore, the current of the test driver is reduced to some extent by the current limiting resistor.

  (6) In another aspect of the power transmission control device of the present invention, a first resonance capacitor and a second capacitor are connected to the primary coil to form a series resonance circuit, and the power transmission side control circuit includes the first After the first capacitor or the second capacitor is charged by the test driver or the second test driver, the resonance circuit is normally driven by the first power transmission driver and the second power transmission driver. Start.

  When normal drive (normal power transmission) is started with no electric charge accumulated in the capacitor, and the coil end is changed from “L” to “H”, an inrush current (instantaneous excess flowing to try to charge the capacitor) The coil end voltage (peak voltage) varies greatly depending on the current. This is not preferable for accurate detection of the coil end voltage (peak voltage). Therefore, after the capacitor is charged using the test driver as a charging current source, normal driving is started, and the coil end (the connection point between the capacitor and the primary coil) is changed from “L” to “H”. . As a result, the inrush current is reduced and the voltage fluctuation is reduced. This is useful for accurate detection of the coil end voltage (peak voltage).

  (7) In another aspect of the power transmission control device of the present invention, the power transmission control device further includes a timing control circuit that controls an operation timing of the power transmission device, and the power transmission device receives a coil end voltage at one end of the primary coil as desired. A first switch circuit for transmitting to the failure detection circuit at the timing of the second, and a second switch circuit for transmitting the coil end voltage of the other end of the primary coil to the failure detection circuit at a desired timing And the timing control circuit includes the first power transmission driver or the first test driver in the low-level driving period or the second half of the high-level driving period at the one end of the primary coil. 1 switch circuit is turned on, the coil end voltage of one end of the primary coil is transmitted to the failure detection circuit, the second power transmission driver or the first In the low level driving period or the second half of the high level driving period of the other end of the primary coil by the test driver, the second switch circuit is turned on, and the coil end voltage at one end of the primary coil is Communicate to the fault detection circuit.

  For accurate fault detection, it is necessary to accurately measure the coil end voltage. Therefore, a switch circuit for transmitting the coil end voltage to the failure detection circuit and a timing control circuit are provided, and the switch circuit has a period during which the initial fluctuation of the coil end voltage is suppressed and the voltage is stable ( It is turned on only during the stable period), and an accurate coil end voltage is transmitted to the failure detection circuit. In other words, the latter half of the high-level period or low-level period of the coil end voltage (the period after the intermediate point between the start point and end point of each period (including the intermediate point)) is a stable period in which voltage fluctuations have been collected. Then, the switch circuit is turned on during that period, and the coil end voltage is transmitted to the failure detection circuit.

  (8) In one aspect of the non-contact power transmission system, the primary coil and the secondary coil are electromagnetically coupled to transmit power from the power transmission device to the power reception device, and power is supplied to the main load of the power reception device. The power transmission device includes: a first power transmission driver that drives one end of the primary coil; a second power transmission driver that drives the other end of the primary coil; The power transmission control device includes a power transmission side control circuit that controls the operation of the power transmission device, and the power transmission side control circuit is configured with a voltage of at least one of the one end and the other end of the primary coil. It has a failure detection circuit that monitors a certain coil end voltage and detects a failure of the first power transmission driver and the second power transmission driver, and the failure detection circuit includes the first power transmission driver and the second power transmission driver. Power transmission driver The coil end voltage is monitored during normal driving, and the coil end voltage is not the coil end voltage corresponding to the input signal of the first power transmission driver or the second power transmission driver. The power transmission driver of 1 or the second power transmission driver is determined to be faulty, and power transmission to the power receiving device is stopped, and the power receiving device rectifies the dielectric voltage of the secondary coil. A power reception unit including a load modulation unit for data transmission from the power reception device to the power transmission device, and a power supply control unit that controls power supply to the main load.

  As a result, it is possible to detect a failure of the driver that drives the primary coil during normal driving and stop power transmission or notify the failure. Therefore, the safety of the contactless power transmission system is improved.

  (9) In another aspect of the contactless power transmission system of the present invention, the power transmission device drives a first test driver that drives the one end of the primary coil and the other end of the primary coil. The power transmission side control circuit before normally driving the primary coil by the first power transmission driver and the second power transmission driver. The level of each input signal of the power transmission driver or the second power transmission driver is set to a level at which the one end or the other end of the primary coil is in a floating state, and in this state, the first test driver or the first power driver The one end or the other end of the primary coil is driven by two test drivers, and the failure detection circuit is configured such that the voltage at the one end of the primary coil or the voltage at the other end is An initial failure occurs in the first power transmission driver or the second power transmission driver when the voltage does not correspond to the drive output level of the first test driver or the second test driver. It is determined that power transmission is stopped.

  As a result, it is possible to detect an initial failure of the driver that drives the primary coil and perform failure notification, device recovery, repair, and the like without performing normal power transmission. Therefore, the safety of the non-contact power transmission system is further improved.

  (10) The power transmission device of the present invention includes the power transmission control device of the present invention, and a power transmission unit including the first and second power transmission drivers that drive the primary coil.

  By this invention, the power transmission part for non-contact electric power systems with high safety | security is realizable.

  (11) The electronic device of the present invention includes the power transmission device of the present invention.

  According to the present invention, a highly safe electronic device capable of contactless power transmission (for example, a charging stand (cradle) having a function of charging a secondary battery of a mobile terminal by contactless power transmission) can be obtained.

  As described above, according to the present invention, it is possible to detect a short circuit failure of the driver of the primary coil, and to improve the safety of the contactless power transmission system.

A preferred embodiment of the present invention will be described with reference to the drawings.
The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

(First embodiment)
First, an example of a suitable electronic device to which the present invention is applied and the principle of contactless power transmission technology will be described.

(Examples of electronic devices and the principle of contactless power transmission)
1A and 1B are diagrams for explaining a contactless power transmission technique, FIG. 1A is a diagram illustrating an example of an electronic device to which a contactless power transmission technique is applied, and FIG. These are the figures for demonstrating the principle of non-contact electric power transmission using an induction transformer.

  As illustrated in FIG. 1A, a charger 500 (cradle) that is one of electronic devices includes a power transmission device 10. A mobile phone 510 that is one of the electronic devices includes a power receiving device 40. The mobile phone 510 includes a display unit 512 such as an LCD, an operation unit 514 including buttons and the like, a microphone 516 (sound input unit), a speaker 518 (sound output unit), and an antenna 520.

  Electric power is supplied to the charger 500 via the AC adapter 502, and this electric power is transmitted from the power transmitting device 10 to the power receiving device 40 by contactless power transmission. Thereby, the battery of the mobile phone 510 can be charged or the device in the mobile phone 510 can be operated.

  The electronic device to which this embodiment is applied is not limited to the mobile phone 510. For example, the present invention can be applied to various electronic devices such as wristwatches, cordless telephones, shavers, electric toothbrushes, wrist computers, handy terminals, portable information terminals, and electric bicycles.

  Examples of particularly suitable electronic devices include mobile terminals (including mobile phone terminals, PDA terminals, portable personal computer terminals) and watches (watches). Since the power receiving device of the present invention is simple in configuration and small in size, it can be mounted on a portable terminal or the like and has low loss. For example, the charging time of a secondary battery in an electronic device can be shortened. In addition, since the heat generation is reduced, the reliability of the electronic device from the viewpoint of safety is also improved.

  In particular, mobile terminals (including mobile phone terminals, PDA terminals, and portable personal computer terminals) have a large amount of charging current at high loads, and the problem of heat generation is likely to become obvious. Therefore, it can be said that the present invention can fully utilize the low loss and low heat generation characteristics of the present invention.

  As schematically shown in FIG. 1B, power transmission from the power transmission device 10 to the power reception device 40 is performed on the primary coil L1 (power transmission coil) provided on the power transmission device 10 side and on the power reception device 40 side. This is realized by electromagnetically coupling the secondary coil L2 (power receiving coil) formed to form a power transmission transformer. Thereby, non-contact power transmission becomes possible.

(Configuration example of power transmission device and power reception device)
FIG. 2 is a circuit diagram illustrating an example of a specific configuration of each unit in a contactless power transmission system including a power transmission device, a power reception device, and a load.

  As illustrated, the power transmission device 10 is provided with a power transmission control device 20 and a power transmission unit 12. The power receiving device 40 includes a power receiving unit 42, a load modulation unit 46, and a power supply control unit 48. The load 90 includes a charge control device 92 and a battery (secondary battery) 94. This will be specifically described below.

  A power transmission-side electronic device such as the charger 500 in FIG. 1A includes at least the power transmission device 10 illustrated in FIG. In addition, a power receiving-side electronic device such as the mobile phone 510 includes at least the power receiving device 40 and a load 90 (main load). 2, the primary coil L1 and the secondary coil L2 are electromagnetically coupled to transmit power from the power transmitting apparatus 10 to the power receiving apparatus 40, and from the voltage output node NB7 of the power receiving apparatus 40 to the load 90. Thus, a non-contact power transmission (non-contact power transmission) system that supplies power (voltage VOUT) to the power source is realized.

  The power transmission device 10 (power transmission module, primary module) can include a primary coil L1, a power transmission unit 12, a voltage detection circuit 14, a display unit 16, and a power transmission control device 20. The power transmission device 10 and the power transmission control device 20 are not limited to the configuration in FIG. 2, and some of the components (for example, the display unit and the voltage detection circuit) are omitted, other components are added, and the connection is made. Various modifications such as changing the relationship are possible.

  The power transmission unit 12 generates an AC voltage having a predetermined frequency during power transmission, and generates an AC voltage having a different frequency according to data during data transfer, and supplies the AC voltage to the primary coil L1. Specifically, as illustrated in FIG. 3A, for example, when data “1” is transmitted to the power receiving device 40, an AC voltage of frequency f1 is generated and data “0” is transmitted. If so, an alternating voltage of frequency f2 is generated. The power transmission unit 12 includes at least a first power transmission driver that drives one end of the primary coil L1, a second power transmission driver that drives the other end of the primary coil L1, and a resonance circuit together with the primary coil L1. One capacitor can be included. Each of the first and second power transmission drivers included in the power transmission unit 12 is, for example, an inverter circuit (or buffer circuit) configured by a power MOS transistor, and is controlled by the driver control circuit 26 of the power transmission control device 20. The

  The primary coil L1 (power transmission side coil) is electromagnetically coupled to the secondary coil L2 (power reception side coil) to form a power transmission transformer. For example, when power transmission is necessary, as shown in FIGS. 1A and 1B, a mobile phone 510 is placed on the charger 500, and the magnetic flux of the primary coil L1 passes through the secondary coil L2. Make it like this.

  On the other hand, when power transmission is unnecessary, the charger 500 and the mobile phone 510 are physically separated so that the magnetic flux of the primary coil L1 does not pass through the secondary coil L2.

  The voltage detection circuit 14 is a circuit that detects the induced voltage of the primary coil L1, and is, for example, between the resistors RA1 and RA2 or the connection node NA3 of the RA1 and RA2 and the GND (low-potential side power supply in a broad sense). It includes a provided diode DA1. Specifically, a signal PHIN obtained by dividing the induced voltage of the primary coil by the resistors RA1 and RA2 is input to the waveform detection circuit 28 of the power transmission control device 20.

  The display unit 16 displays various states of the contactless power transmission system (during power transmission, ID authentication, etc.) using colors, images, and the like. For example, an LED (light emitting diode) or LCD (liquid crystal display device). And so on.

  The power transmission control device 20 is a device that performs various controls of the power transmission device 10, and can be realized by an integrated circuit device (IC) or the like. The power transmission control device 20 can include a control circuit 22 (power transmission side), an oscillation circuit 24, a driver control circuit 26, and a waveform detection circuit 28.

  The control circuit 22 (control unit) controls the power transmission device 10 and the power transmission control device 20, and can be realized by, for example, a gate array or a microcomputer. Specifically, the control circuit 22 performs various sequence controls and determination processes necessary for power transmission, load detection, frequency modulation, foreign object detection, and attachment / detachment detection.

  The oscillation circuit 24 is configured by, for example, a crystal oscillation circuit, and generates a power transmission side clock. The driver control circuit 26 generates a control signal having a desired frequency based on the clock generated by the oscillation circuit 24, the frequency setting signal from the control circuit 22, and the like, and outputs the control signal to a power transmission driver (not shown) of the power transmission unit 12. Then, the operation of the power transmission driver is controlled.

  The waveform detection circuit 28 monitors the waveform of the signal PHIN corresponding to the induced voltage at one end of the primary coil L1, and performs load detection, foreign object detection, and the like. For example, when the load modulation unit 46 of the power receiving device 40 performs load modulation for transmitting data to the power transmission device 10, the signal waveform of the induced voltage of the primary coil L1 changes correspondingly.

  Specifically, as illustrated in FIG. 3B, when the load modulation unit 46 of the power receiving device 40 reduces the load in order to transmit data “0”, the amplitude (peak voltage) of the signal waveform decreases. When the load is increased to transmit the data “1”, the amplitude of the signal waveform increases. Therefore, the waveform detection circuit 28 performs peak hold processing of the signal waveform of the induced voltage and determines whether or not the peak voltage exceeds the threshold voltage, whereby the data from the power receiving device 40 is “0”. Whether it is “1” or not. The waveform detection method is not limited to the above-described method. For example, whether the load on the power receiving side has increased or decreased may be determined using a physical quantity other than the peak voltage.

  The power reception device 40 (power reception module, secondary module) can include a secondary coil L2, a power reception unit 42, a load modulation unit 46, a power supply control unit 48, and a power reception control device 50. The power reception device 40 and the power reception control device 50 are not limited to the configuration shown in FIG. 2, and various modifications such as omitting some of the components, adding other components, and changing the connection relationship. Implementation is possible.

  The power receiving unit 42 converts the AC induced voltage of the secondary coil L2 into a DC voltage. This conversion is performed by a rectifier circuit 43 included in the power receiving unit 42. The rectifier circuit 43 includes diodes DB1 to DB4. The diode DB1 is provided between the node NB1 at one end of the secondary coil L2 and the generation node NB3 of the DC voltage VDC, and DB2 is provided between the node NB3 and the node NB2 at the other end of the secondary coil L2. , DB3 is provided between the node NB2 and the VSS node NB4, and DB4 is provided between the nodes NB4 and NB1.

  The resistors RB1 and RB2 of the power receiving unit 42 are provided between the nodes NB1 and NB4. A signal CCMPI obtained by dividing the voltage between the nodes NB1 and NB4 by the resistors RB1 and RB2 is input to the frequency detection circuit 60 of the power reception control device 50.

  The capacitor CB1 and the resistors RB4 and RB5 of the power receiving unit 42 are provided between the node NB3 of the DC voltage VDC and the node NB4 of VSS. A divided voltage VD4 obtained by dividing the voltage between the nodes NB3 and NB4 by the resistors RB4 and RB5 is input to the power receiving side control circuit 52 and the position detection circuit 56 via the signal line LP2. As for the position detection circuit 56, the divided voltage VD4 serves as a signal input (ADIN) for position detection.

  The load modulation unit 46 performs load modulation processing. Specifically, when desired data is transmitted from the power reception device 40 to the power transmission device 10, the load at the load modulation unit 46 (power reception side) is variably changed according to the transmission data to induce the primary coil L1. Change the voltage signal waveform. For this purpose, the load modulation unit 46 includes a resistor RB3 and a transistor TB3 (N-type CMOS transistor) provided in series between the nodes NB3 and NB4.

  This transistor TB3 is ON / OFF controlled by a control signal P3Q given from the power reception side control circuit 52 of the power reception control device 50 via the signal line LP3. In the authentication stage before normal power transmission is started, when the transistor TB3 is turned on / off to perform load modulation to transmit a signal to the power transmission device, the transistors TB1 and TB2 of the power supply control unit 48 are turned off. The load 90 is not electrically connected to the power receiving device 40.

  For example, when the power receiving side is set to a low load (impedance is large) in order to transmit data “0”, the signal P3Q becomes L level and the transistor TB3 is turned off. As a result, the load of the load modulator 46 becomes almost infinite (no load). On the other hand, when the power receiving side is set to a high load (impedance is small) to transmit data “1”, the signal P3Q becomes H level and the transistor TB3 is turned on. As a result, the load of the load modulation unit 46 becomes the resistance RB3 (high load).

  The power supply control unit 48 controls power supply to the load 90. The regulator (LDO) 49 adjusts the voltage level of the DC voltage VDC obtained by the conversion in the rectifier circuit 43, and generates a power supply voltage VD5 (for example, 5V). The power reception control device 50 operates by being supplied with the power supply voltage VD5, for example.

  The transistor TB2 (P-type CMOS transistor) is provided between the generation node NB5 (output node of the regulator 49) of the power supply voltage VD5 and the transistor TB1 (node NB6), and is supplied from the control circuit 52 of the power reception control device 50. Is controlled by the signal P1Q. Specifically, the transistor TB2 is turned on when the ID authentication is completed (established) and normal power transmission (ie, normal power transmission) is performed.

  A pull-up resistor RU2 is provided between the power supply voltage generation node NB5 and the node NB8 of the gate of the transistor TB2.

  The transistor TB1 (P-type CMOS transistor) is provided between the transistor TB2 (node NB6) and the voltage output node NB7 of VOUT, and is controlled by a signal P4Q from the output guarantee circuit 54. Specifically, it is turned on when ID authentication is completed and normal power transmission is performed. On the other hand, when the connection of the AC adapter is detected or the power supply voltage VD5 is smaller than the operation lower limit voltage of the power reception control device 50 (control circuit 52), it is turned off. A pull-up resistor RU1 is provided between the voltage output node NB7 and the node NB9 of the gate of the transistor TB1.

  The power reception control device 50 is a device that performs various controls of the power reception device 40 and can be realized by an integrated circuit device (IC) or the like. The power reception control device 50 can be operated by a power supply voltage VD5 generated from the induced voltage of the secondary coil L2. The power reception control device 50 can include a control circuit 52 (power reception side), an output guarantee circuit 54, a position detection circuit 56, an oscillation circuit 58, a frequency detection circuit 60, and a full charge detection circuit 62.

  The power receiving side control circuit 52 controls the power receiving device 40 and the power receiving control device 50, and can be realized by, for example, a gate array or a microcomputer. The power receiving side control circuit 52 operates using the constant voltage (VD5) at the output terminal of the series regulator (LDO) 49 as a power source.

  Specifically, the power receiving side control circuit 52 includes ID authentication, position detection, frequency detection, full charge detection, load modulation for communication for authentication, and load for communication to enable foreign object insertion detection. Various sequence control and determination processing necessary for modulation and the like are performed.

  The output guarantee circuit 54 is a circuit that guarantees the output of the power receiving device 40 at a low voltage (at 0 V). That is, the transistor TB1 is controlled, and when the connection of the AC adapter is detected, or when the power supply voltage VD5 is smaller than the operation lower limit voltage, the transistor TB1 is set to be turned off and the voltage output node NB7 is connected to the power receiving device 40 side. Prevent backflow of current into the.

  The position detection circuit 56 monitors the waveform of the signal ADIN corresponding to the waveform of the induced voltage of the secondary coil L2, and determines whether the positional relationship between the primary coil L1 and the secondary coil L2 is appropriate. Specifically, the signal ADIN is converted into a binary value by a comparator, and it is determined whether or not the positional relationship is appropriate.

  The oscillation circuit 58 is constituted by, for example, a CR oscillation circuit, and generates a power receiving side clock. The frequency detection circuit 60 detects the frequency (f1, f2) of the signal CCMPI and determines whether the transmission data from the power transmission device 10 is “1” or “0”.

  The full charge detection circuit 62 (charge detection circuit) is a circuit that detects whether or not the battery 94 of the load 90 is in a fully charged state (charged state). Specifically, the full charge detection circuit 62 detects the full charge state by detecting on / off of the LEDR used for displaying the charge state, for example. That is, when the LEDR is extinguished continuously for a predetermined time (for example, 5 seconds), it is determined that the battery 94 is fully charged (charging is completed). Further, the charge control device 92 in the load 90 can also detect the fully charged state based on the lighting state of the LEDR.

  The load 90 includes a charge control device 92 that performs charge control of the battery 94 and the like. The charging control device 92 can detect the fully charged state based on the lighting state of the light emitting device (LEDR). The charge control device 92 (charge control IC) can be realized by an integrated circuit device or the like. Note that, like a smart battery, the battery 94 itself may have the function of the charging control device 92. The load 90 is not limited to the secondary battery.

(Specific circuit configuration of power transmission unit and coil end voltage monitoring)
FIG. 4 is a circuit diagram for explaining a specific circuit configuration of the power transmission unit and monitoring of the coil end voltage.

  As illustrated, the power transmission driver 13 provided in the power transmission unit 12 of the power transmission device 10 drives the coil end (upper end) N1 of the primary coil L1. The power transmission driver 13 is a CMOS buffer including a PMOS transistor M1 and an NMOS transistor M2 connected in series between power supply voltages (VDD1: 5V, for example), and the gate of each transistor is an individual gate drive signal (DRP1). , DRN1).

  When the PMOS transistor M1 is turned on, the drive output of the CMOS buffer becomes “H” level, and when the NMOS transistor M2 is turned on, the drive output of the CMOS buffer becomes “L” level, and the PMOS transistor M1 and the NMOS transistor M2 are turned on. When both are off, the output end of the CMOS buffer is in a floating state (potential indefinite state). The floating state can also be regarded as a high impedance state, and thus the power transmission driver 13 is also a tristate buffer.

  The power transmission driver 15 drives the coil end (lower end) N2 of the primary coil L1. The power transmission driver 15 is a CMOS buffer composed of a PMOS transistor M3 and an NMOS transistor M4 connected in series between power supply voltages (VDD1: for example, 5V), and the gate of each transistor has an individual gate drive signal (DRP2). , DRN2). The power transmission driver 15 is also a tri-state buffer whose output terminal potential can take three states of “H” level, “L” level, and a floating state.

  Moreover, the power transmission part 12 has two capacitors (C1 and C2) connected in series to the primary coil L1. Primary coil L1 and capacitors C1 and C2 constitute a series resonant circuit. If the resonance frequency of the series resonance circuit is f0, the frequencies f1 and f2 for transmitting “1” and “0” to the secondary side are set, for example, in a region on the higher frequency side than the resonance frequency f0. Is done.

  In the present invention, the voltage at the coil ends (N1, N2) of the primary coil L1 is monitored in order to detect a failure or initial failure during normal driving of the power transmission driver (13, 15). The coil ends (N1, N2) are also output ends of the power transmission drivers (13, 15). Based on the voltages (that is, coil end voltages) DRV1 and DRV2 at the coil ends (N1, N2) of the primary coil L1, a failure detection circuit (not shown in FIG. 4; described in FIG. 10) is connected to a power transmission driver ( 13) Determine whether or not there is a failure.

(Fault detection during normal driving)
FIGS. 5A to 5D are diagrams for explaining the detection principle of a failure (normal failure) during normal driving of the power transmission driver. Here, the failure detection of the power transmission driver 13 will be described (the failure detection of the power transmission driver 15 is also the same).

  As shown in FIG. 5A, when both DRP1 and DRP2 are set to “L”, if the power transmission driver 13 is normal (when there is no failure), the PMOS transistor M1 is turned on, the NMOS transistor M2 is turned off, and the output The potential at the end should be “H”. However, for example, as shown in FIG. 5B, if a short-circuit fault occurs in the NMOS transistor M2, the NMOS transistor M2 that should have been turned off is substantially turned on. A large through current IR is generated in a period in which the transistor M1 is turned on. When the through current repeatedly flows, the normal PMOS transistor M1 eventually fails, and in this case, the worst situation of short-circuiting between power supplies is caused.

  Therefore, the potential of the output terminal (coil end N1 of the primary coil) of the power transmission driver 13 is monitored, and it is detected whether or not the potential corresponds to the voltage level of the input signal of the power transmission driver 13. By detecting the failure.

  That is, if no short-circuit failure has occurred in the NMOS transistor M2, as shown in FIG. 5A, when both DRP1 and DRN2 are “L”, the voltage at the output terminal should be “H”. On the other hand, if a short circuit failure has occurred in the NMOS transistor M2, as shown in FIG. 5B, the output terminal voltage is a voltage other than the “H” level (for example, a voltage that is ½ of the power supply voltage). . Thus, by monitoring the voltage at the output terminal (coil terminal N1 of the primary coil) of the power transmission driver, it is possible to detect a short-circuit failure of the NMOS transistor M2.

In FIG. 5C, both DRP1 and DRN1 which are input signals of the power transmission driver 13 are set to the “H” level. In this case, the PMOS transistor M1 should be turned off and the NMOS transistor M2 should be turned on. However, when a short-circuit fault has occurred in the PMOS transistor M1, a large through current during driving is generated as shown in FIG. IR may flow, and while this is repeated, both transistors may fail, resulting in a short circuit between power supplies.
Therefore, the voltage at the output end of the power transmission driver 13 (the voltage at the coil end N2 of the primary coil) is monitored, and it is detected whether the potential corresponds to the voltage level of the input signal of the power transmission driver 13. This detects a failure.

  That is, if no short-circuit failure has occurred in the PMOS transistor M1, as shown in FIG. 5C, when both DRP1 and DRN2 are “H”, the voltage at the output terminal should be “L”. On the other hand, if a short circuit failure has occurred in the PMOS transistor M1, as shown in FIG. 5D, the output terminal voltage becomes a voltage other than the “L” level (for example, a voltage that is ½ of the power supply voltage). . Thus, by monitoring the voltage at the output end of the power transmission driver (coil end N2 of the primary coil), it is possible to detect a short-circuit fault in the PMOS transistor M1.

  The failure detection circuit (reference numeral 34 in FIG. 10) performs the above-described failure detection during normal driving of the driver (during normal power transmission) and promptly detects a short-circuit failure that occurred during normal driving (during normal power transmission). To detect. Accordingly, for example, it is possible to quickly take appropriate measures such as stopping power transmission and notifying a failure.

(Detection of initial failure of power transmission driver)
6A and 6B are diagrams for explaining the principle of initial failure detection of the power transmission driver, FIG. 6A is a diagram showing a case where there is no failure, and FIG. 6B is a case where there is a failure. FIG.

  If a failure has occurred in the power transmission drivers 13 and 15, it is desirable to detect the failure before normal driving (normal power transmission) and repair the device without performing normal power transmission. Therefore, in the present invention, preferably, an initial failure is also detected before normal driving.

  6A and 6B, a test driver TE1 is provided in order to enable detection of an initial failure of the power transmission driver 13. Similarly, a test driver TE2 is provided for detecting an initial failure of the power transmission driver 15 (not shown in FIG. 6).

  As shown in FIGS. 6A and 6B, the test driver TE1 includes a PMOS transistor M5, an NMOS transistor M6, and current limiting resistors R1 and R2 connected in series between the power supplies. Is done.

  The reason why the current limiting resistors R1 and R2 are provided is as follows. That is, if the current driving capability of the test driver TE1 (TE2) is too high, the leakage current is masked when the leakage current of each transistor constituting the power transmission drivers 13 and 15 in which the initial failure has occurred is small. Therefore, it cannot be said that the initial failure may not be detected. Therefore, the current of the test driver is reduced to some extent by the current limiting resistors (R1, R2).

  The initial failure detection procedure is as follows. First, the input signals (DRP1, DRN1) of the transistors (M1, M2) of the power transmission driver 13 are set to “H” and “L”, and both transistors (M1, M2) are turned off. As a result, the primary coil end (N1) enters a floating state.

  Next, in this state, the coil end (N1) is driven by the test driver TE1. The power transmission driver 13 is disabled, and the voltage at the coil end (N1) is under the control of the test driver TE1, and therefore the voltage at the coil end (N1) is the drive voltage (output end) of the test driver TE1. Voltage) should change.

  For example, as shown in FIG. 6A, when the input signals (INTP1 and INTP2) of the transistors M5 and M6 constituting the test driver TE1 are both set to “L”, the PMOS transistor M5 is turned on, and the test The voltage at the output terminal of the driver TE1 is “H”. Due to the charging current I1 from the power supply VDD1, the voltage at the coil end (N1) also rises to the “H” level. This is a normal circuit operation when the power transmission driver 13 has no initial failure.

  On the other hand, as shown in FIG. 6B, for example, when the NMOS transistor M2 of the power transmission driver 13 is out of order, even if the voltage at the output terminal of the test driver TE1 becomes “H”, the power transmission driver Due to the leakage current I2 of the NMOS transistor M2, the voltage at the coil end (N1) does not reach the “H” level (for example, becomes a voltage half of the power supply voltage).

  As described above, when the initial failure occurs in the power transmission driver 13, the coil end voltage does not match the drive voltage of the test driver TE1 due to the leakage current of the failed transistor. Therefore, the initial failure is detected. can do.

  When an initial failure is detected, for example, normal driving is disabled and the initial failure is notified. As a result, for example, it is possible to quickly take appropriate measures such as collecting and repairing the device, and safety is further improved.

(Capacitor initial failure detection)
In the above description, the initial failure of the transistor constituting the power transmission driver 13 (and 15) is detected, but the initial failure of the capacitors (C1, C2) constituting the series resonance circuit together with the primary coil (L1) is detected. You can also.

  FIG. 7 is a diagram for explaining the principle of detection of an initial failure of a capacitor constituting the resonance circuit. In FIG. 7, two test drivers (TE1, TE2) are operated simultaneously to change the voltages at the first and second coil ends (N1, N2) in a complementary manner. As shown in FIG. 7, for example, when the output voltage of the test driver TE1 is changed from “L” to “H”, the output voltage of the test driver TE2 is changed from “H” to “L” in synchronization therewith. (Ie complementary).

  As a result, the AC component generated by the voltage change flows from the first coil end (N1) to the second coil end (N2) via the first and second capacitors (C1, C2). Therefore, when the AC fluctuation of the coil end voltage due to the AC component cannot be detected, it can be determined that an initial failure has occurred in either the first or second capacitor (C1, C2).

  That is, as shown in the lower side of FIG. 7, the voltage (DRV2) at the coil end (N2) is monitored, and if an alternating current component such as A1 can be detected, it is determined as normal and incomplete fluctuations such as A2 occur. When it is detected or when no fluctuation is observed as in A3, it can be determined that an initial failure has occurred in at least one of the capacitors (C1, C2).

  When an initial failure of the capacitor is detected, for example, normal driving is disabled and the initial failure is notified. As a result, it is possible to promptly take appropriate measures such as collecting and repairing the device, and the safety is further improved.

(Suppression of peak voltage fluctuation by preventing inrush current)
The test driver TE1 (TE2) can be used not only for failure detection but also for suppressing fluctuations in peak voltage by preventing inrush current.

  That is, when normal driving (normal power transmission) is started in a state where no charge is accumulated in the capacitors (C1, C2), and the coil end is changed from “L” to “H”, an inrush current (charge the capacitor) The coil end voltage (peak voltage) fluctuates greatly due to the instantaneous excess current that flows. This is not preferable for accurate detection of the coil end voltage (peak voltage).

  Therefore, after the capacitors (C1, C2) are charged (precharged) using the test drivers (TE1, TE2) as the charging current source, normal driving is started, and the coil ends (the capacitors and the primary coil are connected to each other). The connection point is changed from “L” to “H”. As a result, the inrush current is reduced and the voltage fluctuation is reduced. This is useful for accurate detection of the coil end voltage (peak voltage).

  FIGS. 8A to 8C are diagrams for explaining peak voltage fluctuation suppression by preventing inrush current. The transistor (M1) and the resistor (R1) on the power source side of the test driver TE1 can be used as a charging current source (ISC) for charging the capacitor C1. That is, before normal driving, the charging current source (ISC) of the test driver TE1 is operated to charge the capacitor C1. Then, normal driving is started, and the coil end N1 is changed from “L” to “H”.

  When the capacitor C1 is not charged in advance, the maximum amplitude (ringing RG) of the initial fluctuation (ringing RG) of the voltage (DRV1) at the coil end N1 is large as W1, as shown in FIG. In this case, the maximum amplitude of the initial fluctuation (ringing RG) of the voltage (DRV1) at the coil end N1 is reduced to W2 by reducing the inrush current. This is useful for accurate detection of the coil end voltage (peak voltage).

(Monitor timing of coil end voltage)
In order to detect a failure with high accuracy, it is necessary to accurately measure the coil end voltage. Therefore, in the present invention, a monitor window circuit (broadly defined switch circuit) is provided in order to transmit the coil end voltage to the failure detection circuit, and a timing control circuit is provided, and the monitor window circuit (switch circuit) is connected to the coil end. It is turned on only during a period in which the initial voltage fluctuation is suppressed and the voltage is stable (stable period), and an accurate coil end voltage is transmitted to the failure detection circuit (reference numeral 34 in FIG. 10).

  9A and 9B are diagrams showing the configuration and operation timing of the monitor window circuit (switch circuit), FIG. 9A is a diagram showing the configuration of the monitor window circuit, and FIG. It is a figure which shows an off timing.

  As shown in the figure, the monitor window circuit (MWD1: switch circuit in a broad sense) operates with the switch SW1 whose on / off is controlled by the monitor timing signal (Q8) and the power supply voltage VDD1 (for example, 5 V) of the power transmission unit 12. And an inverter INV1.

  The monitor window circuit (MWD2) has the same configuration, and on / off of the switch is controlled by the monitor timing signal (Q9). The monitor timing signal is generated by a timing control circuit (reference numeral 33 in FIG. 10).

The switch (SW1) of the monitor window circuit is turned on while avoiding the initial fluctuation period of the high level period (or low level period) of the coil end voltage DRV1 (DRV2), and a failure detection circuit (FIG. 10) samples a stable voltage. To the reference numeral 34).

  Therefore, as shown in FIG. 9B, the switch (SW1) of the monitor window circuit is turned on in the latter half of the high level period (or low level period) of the coil end voltage DRV1 (DRV2). As shown in the figure, the “second half period” is a period (intermediate time point (t2)) after a time point (t2) between the start time point (t1) and the end time point (t4) of the high level period (low level period). This second half period is a stable period in which initial voltage fluctuations are settled.

  In FIG. 9B, at time t3 in the second half period, the switch SW1 is turned on, and a stable coil end voltage is sampled and transmitted to the failure detection circuit (reference numeral 34 in FIG. 10).

(Example of specific internal circuit configuration of power transmission control device and power transmission unit)
FIG. 10 is a block diagram illustrating an example of a specific internal circuit configuration of the power transmission control device and the power transmission unit. 10, parts that are the same as those in FIG. 2 are given the same reference numerals.

  The power transmission control device 20 includes an oscillation circuit 24, a power transmission side control circuit 22, and a driver control circuit 26.

  The power transmission side control circuit 22 includes a drive clock generation circuit 31, a counter 32, a timing control circuit 33, a failure detection circuit 34, and inverters INV3 and INV4 that operate with a power supply voltage (VDD2: 3V, for example) of the power transmission control device 10. And flip-flops 35 and 36. The driver control circuit 26 includes power MOS drive circuits (27, 29).

  The power transmission unit 12 includes power transmission drivers (13, 15), test drivers (TE1, TE2), and monitor windows (MWD1, MWD2).

  The timing control circuit 33 controls the operation timing of the power MOS drive circuit 27 by using the timing control signals Q1 and Q2, thereby determining the high / low switching timing of the input signals (DRP1 and DRN2) of the power transmission driver 13. The Similarly, the timing control circuit 33 controls the operation timing of the power MOS drive circuit 29 by using the timing control signals Q3 and Q4, whereby the high / low switching timing of the input signals (DRP2 and DRN2) of the power transmission driver 15 is controlled. Is determined.

  Further, the timing control circuit 33 controls the on / off timing of each of the transistors (M5, M6) constituting the test driver TE1 by timing control signals Q6, Q7 (corresponding to INTP1, INTP2 in FIG. 11). To do. Similarly, the timing control circuit 33 uses the timing control signals Q10 and Q11 (corresponding to INTP2 and INTN2 in FIG. 11) to control the on / off timing of each of the transistors (M7 and M8) constituting the test driver TE2. Control.

  Further, the timing control circuit 33 controls the on / off timing of each of the switches (SW1, SW2) constituting the monitor window circuits (MWD1, MWD2) by timing control signals Q8, Q9 (corresponding to DRVON in FIG. 11). Control.

  The timing control circuit 33 controls the latch timing of the flip-flops (FF35 and FF36) by using timing control signals Q12 and Q13 (corresponding to the latch signal LATH in FIG. 11).

(Example of specific operation timing of each part of power transmission device in FIG. 10)
FIG. 11 is a timing diagram illustrating an example of specific operation timings of the power transmission device illustrated in FIG. 10.

  In FIG. 11, “DRP1 and DRN1” are input signals of the power transmission driver 13, “DRV1” is the voltage (coil end voltage) at the coil end (N1), and “INTP1 and INTN2” are test drivers. This is an input signal of (TE1) and corresponds to the timing control signals Q6 and Q7 of FIG.

  “DRP21 and DRN2” are input signals of the power transmission driver 15, “DRV2” is a voltage (coil end voltage) at the coil end (N2), and “INTP2 and INTN2” are test drivers (TE2). ) And corresponds to the timing control signals Q10 and Q11 of FIG.

  DRVON is an on / off control signal for the switches SW1 and SW2 incorporated in the monitor window circuits (MWD1 and MWD2), and corresponds to the timing control signals (Q8 and Q9) in FIG.

  LATH is a touch timing control signal for controlling the latch timing of the flip-flops (FF35 and FF36) in FIG. 10, and corresponds to the timing control signals Q12 and Q13 in FIG.

  In FIG. 11, a period indicated by hatching indicates a period in which the plurality of transistors that determine the potential at a predetermined location are both turned off and the potential cannot be specified.

  In FIG. 11, the voltage change timings of the PMOS transistor and NMOS transistor constituting the CMOS type driver are intentionally shifted so that both transistors are turned on simultaneously and a large through current does not flow. .

  In FIG. 11, a period T10 (period until time 37) is an initial failure monitoring period, a period T20 (time t37 to t38) is an initial failure determination period, and a period T30 (time t38 to t51) is a normal power transmission period ( Normal failure determination period).

  First, initial failure detection will be described. As described above, in the initial failure detection period (period until time t39), the power transmission drivers 13 and 15 are turned off, and the test drivers (TE1 and TE2) are turned on instead.

  Therefore, DRP1 that is an input signal of power transmission driver TE1 is at “H” level, DRN1 is at “L” level, and similarly, DRP2 that is input signal of power transmission driver TE2 is at “H” level, and DRN2 is This is the “L” level, and the output terminals of the power transmission drivers 13 and 15 are thereby in a floating state.

  In this state, at time t32, the input signal INTP1 (Q6) of the test driver TE1 changes from “L” to “H”, and at time t33, INTN1 (Q7) changes from “L” to “H”. Change. INTN1 (Q7) returns to the “L” level at time t36.

  Similarly, the input signal INTP2 (Q10) of the test driver TE2 changes from “H” to “L”. This INTP2 (Q10) returns to the “H” level at time t37. At time t33, INTN2 (Q11) changes from “H” to “L”.

  The first coil end (N1) voltage DRV1 is at the “H” level during the period from time t33 to time t36. Similarly, the second coil end (N2) voltage DRV2 is at the “L” level during the period from time t33 to time t37. That is, the first and second coil ends (N1, N2) are driven simultaneously and complementarily.

  The timing control signal DRVON (Q8, Q9) for turning on / off the switches SW1, SW2 of the monitor window circuit (MWD1, MWD2) becomes active at time t34, whereby the switches SW1, SW2 are turned on and the coil ends The voltages (DRV1, DRV2) are sampled. As described above, the time t34 belongs to the latter half of the DRV1 low level period (t33 to t36) and the DRV2 high level period (t33 to t37).

  At time t35, the latch timing control signal (LATH) becomes active, whereby the voltages at the coil ends (N1 and N2) (coil end voltages: DRV1, DRV2) are taken into the flip-flops (FF35, FF36). .

  The failure detection circuit 34 determines whether or not the voltage latched by the FFs 35 and 36 in the period T20 (time t37 to t38) matches the output voltage level of the test drivers TE1 and TE2, and thereby the power transmission driver 13 and 15 initial failures are determined.

  Next, detection of a normal failure during normal power transmission will be described. In the normal power transmission period (T30), since the test drivers TE1 and TE2 are not used, both INTP1 (Q6) and INTP2 (Q10) are fixed to the “H” level, and both INTN1 (Q7) and INTN2 (Q11) Fixed to “L” level.

  On the other hand, DRP1 and DRN1 repeat H / L, and DRP2 and DRN2 repeat H / L. The first and second coil ends (N1, N2) of the primary coil are complementarily driven by the power transmission drivers 13 and 15, and normal power transmission (continuous power transmission with normal power) is performed.

  From time t38 to time t42, the voltage DRV1 at the coil end (N1) becomes “H”, and from time t39 to time t42, the voltage DRV2 at the coil end (N2) becomes “L”.

  The monitor window circuits (MWD1, MWD2) sample “H” of DRV1 and “L” of DEV2 at time t40, and the sampled voltages are latched in flip-flops FF (35, 36) at time t41. Is done.

  Further, from time t43 to time t46, the voltage DRV1 at the coil end (N1) becomes “L”, and from time t43 to time t46, the voltage DRV2 at the coil end (N2) becomes “H”.

  The monitor window circuits (MWD1, MWD2) sample “L” of DRV1 and “H” of DEV2 at time t44, and the sampled voltage is latched in the flip-flop FF (35, 36) at time t45. Is done.

  Thereafter, the same operation is repeated, and during normal power transmission, the voltage at the coil ends (N1, N2) is intermittently sampled and latched by the flip-flops (FF35, 36). Whether the voltage level corresponds to the input signal of each of the drivers 13 and 15 is periodically checked, and when a normal failure occurs, the failure is detected immediately. When a normal failure is detected, an error is notified, the power transmission device 10 is reset, and normal power transmission is stopped. Thereafter, for example, after a predetermined time, the power transmission device 10 is again in the power-on state, and even if an initial failure is detected at that time, the failure is notified without performing normal power transmission, and the power transmission device 10 is repaired or discarded. It will be.

  FIG. 12 is a timing diagram for explaining the relationship between the drive timing of the power transmission driver during normal power transmission, and the voltage monitor timing and voltage latch timing for normal failure detection.

  One cycle of the input signals (DRP1, DRN1) of the power transmission driver 13 corresponds to 62 basic clocks (30 clocks + 32 clocks) as shown on the upper side of FIG. The same applies to the input signals (DRP2, DRN2) of the power transmission driver 15.

  As described above, in each power transmission driver, it is necessary to prevent a through current from flowing. Therefore, the drive timing of each transistor is adjusted so that the PMOS transistor is always turned off when the NMOS transistor is turned on.

  Since voltage fluctuation (RG) occurs at the beginning of the high level period or low level period of the voltages (coil end voltages) DRV1, DRV2 at the first and second coil ends (N1, N2), the monitor window circuit (MWD1) , MWD2) is performed during a stable period (the latter half period in FIG. 12) after the initial voltage fluctuation has converged.

  In FIG. 12, DRP1 and DRN2 change at time t1. DRN1 and DRP2 change at time t2, and DRV1 and DRV2 change accordingly. At a time t3 when the period T1 has elapsed from this time t2, a voltage sampling timing signal (on / off control signal for the switches SW1 and SW2) DRVON in the monitor window circuits (MWD1, MWD2) becomes active. At time t4, LATH becomes active, and the sampled voltage is taken into the flip-flops (FF35, 36). DRVON and LATH become inactive at time t5, DRN1 and DRP2 change at time t6, and DRP1 and DRN2 change at time t7.

  The time when DRVON becomes active (time t3) is 4 clocks before starting from time t7, and the time when LATH becomes active (time t4) is 3 clocks before starting from time t7, and DRVON and LATH are The time when both are inactive (time t5) is two clocks before the time t7. When the period from time t3 to t7 is T2, T1 (time t2 to t3) <T2, and in this example, voltage sampling is performed in the second half of the high-level period or low-level period of DRV1 or DRV2. Will be. The same operation is repeated after time t8.

  Thus, in this embodiment, it is possible to accurately detect both an initial failure and a normal failure.

As described above, according to each embodiment of the present invention, the following effects can be obtained. However, the following effects are not always obtained, and the effects listed below should not be used as a basis for unduly limiting the present invention.
(1) The coil end voltage of the primary coil is monitored, and it is possible to detect a short-circuit failure of the power transmission driver depending on whether or not the coil end voltage corresponds to the input voltage of the power transmission driver. In addition, the safety of the contactless power transmission system can be improved.
(2) Failure detection is performed during normal driving (normal power transmission) of the power transmission driver, and short-circuit failure that occurred during normal driving (normal power transmission) is detected at an early stage to stop power transmission and notify the failure. It is possible to quickly take appropriate measures such as.
(3) An initial failure of the power transmission driver can be detected by providing a test driver and detecting whether or not the coil end voltage matches the drive voltage of the test driver. When an initial failure is detected, for example, by disabling normal driving and notifying the initial failure, for example, it is possible to quickly take appropriate measures such as collecting and repairing the device. More improved.
(4) Whether or not an initial failure has occurred in the capacitor of the series resonance circuit depending on whether or not the coil end is driven simultaneously and complementarily by two test drivers and the fluctuation of the coil end voltage due to the AC component is detected. Can be determined. Therefore, the safety of the power transmission device (and contactless power transmission system) is further improved.
(5) Since the circuit configuration of the test driver is such that a current limiting resistor is interposed between the power supplies, an abnormality in the coil end voltage can be detected even when the leakage current of the transistor of the power transmission driver is small. .
(6) After charging the capacitor using the test driver as a charging current source, normal driving is started and the coil end is changed from “L” to “H”, thereby reducing the inrush current, and the voltage Variation is reduced. This is useful for accurate detection of the coil end voltage (peak voltage).
(7) A switch circuit for transmitting the coil end voltage to the failure detection circuit and a timing control circuit are provided, and the switch circuit has a period during which the initial fluctuation of the coil end voltage is suppressed and the voltage is stable ( By turning on only in the stable period), an accurate coil end voltage can be transmitted to the failure detection circuit. In particular, by turning on the switch circuit in the latter half of the high level period and the low level period, the voltage fluctuation period can be reliably avoided.
(8) Since it is possible to detect a failure of the driver that drives the primary coil during normal driving and to notify the stop of power transmission or the failure, the safety of the contactless power transmission system is improved.
(9) It is possible to detect an initial failure of the driver that drives the primary coil and perform failure notification, equipment recovery, repair, etc. without performing normal power transmission. The safety of the is improved.
(10) A power transmission unit for a contactless power system with high safety can be realized.
(11) According to the present invention, it is possible to detect a short circuit failure of the driver of the primary coil, and to improve the safety of the contactless power transmission system.
(12) According to the present invention, a highly secure contactless power transmission system can be realized, which contributes to the spread of contactless power transmission technology.

  The present invention has been described above with reference to the embodiment. However, the present invention is not limited to this, and various modifications and applications are possible. That is, it will be readily understood by those skilled in the art that many modifications are possible without departing from the scope of the present invention.

  Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, in the specification or the drawings, terms (GND, mobile phone / charger, etc.) described together with different terms having a broader meaning or the same meaning (low-potential side power supply, electronic device, etc.) at least once in the specification or the drawings It can be replaced by the different terms at any point. All combinations of the present embodiment and the modified examples are also included in the scope of the present invention.

  Further, the configuration and operation of the power transmission control device, the power transmission device, the power reception control device, and the power reception device, and the method of detecting the load on the power reception side on the power transmission side are not limited to those described in this embodiment, and various modifications may be made. Is possible.

  The present invention is capable of detecting a failure of a power transmission driver and improving the safety of contactless power transmission technology. Therefore, a power transmission control device (power transmission control IC), a contactless power transmission system, a power transmission device (IC) Module, etc.) and electronic devices (mobile terminals, chargers, etc.). The “mobile terminal” includes a mobile phone terminal, a PDA terminal, and a portable computer terminal.

1A and 1B are diagrams illustrating examples of electronic devices using contactless power transmission. The figure which shows an example of the specific structure of the power transmission apparatus of this invention, a power transmission control apparatus, a power receiving apparatus, and a power receiving control apparatus 3A and 3B are diagrams for explaining the principle of information transmission between the power transmission side device and the power reception side device. The circuit diagram for demonstrating the specific circuit structure of a power transmission part, and monitoring of a coil end voltage. FIGS. 5A to 5D are diagrams for explaining the principle of detecting a failure (normal failure) during normal driving of the power transmission driver. 6A and 6B are diagrams for explaining the principle of detecting an initial failure of a power transmission driver. FIG. 7 is a diagram for explaining the detection principle of the initial failure of the capacitor constituting the resonance circuit. FIG. 8A to FIG. 8C are diagrams for explaining fluctuation suppression of peak voltage by preventing inrush current. 9A and 9B are diagrams showing the configuration and operation timing of the monitor window circuit (switch circuit). The block diagram which shows the example of the specific internal circuit structure of a power transmission control apparatus and a power transmission part Timing chart showing an example of specific operation timing of the power transmission device shown in FIG. Timing diagram for explaining the relationship between the drive timing of the power transmission driver and the voltage monitor timing and voltage latch timing for normal failure detection

Explanation of symbols

L1 primary coil, L2 secondary coil, 10 power transmission device, 12 power transmission unit,
13, 15 Power transmission driver, C1, C2 Capacitor constituting the series resonance circuit,
DRP1 and DRN1 input signals of the power transmission driver 13,
DRP2 and DRN2 input signals of the power transmission driver 15,
TE1, TE2 test driver,
17, 19 CMOS buffer constituting a test driver;
INTP1 and INTN1 input signals of the CMOS buffer 17 constituting the test driver,
INTP2 and INTN2 input signals of CMOS buffer 19 constituting the test driver, MWD1, MWD2 monitor window circuit,
DRVON (Q8, Q9) monitor timing signal (voltage sampling timing signal),
DRV1, DRV2 coil end voltages of the first and second coil ends (N1, N2),
14 voltage detection circuit, 16 display unit, 20 power transmission control device, 22 power transmission side control circuit,
24 power transmission side oscillation circuit, 26 driver control circuit, 28 waveform detection circuit,
40 power receiving device, 42 power receiving unit, 43 rectifier circuit, 46 load modulation unit,
48 Power supply control unit, 50 Power reception control device, 52 Power reception side control circuit, 54 Output guarantee circuit,
56 position detection circuit, 58 power reception side oscillation circuit, 60 frequency detection circuit,
62 full charge detection circuit, 90 full load of power receiving device,
92 charge control device (charge control IC), 94 battery (secondary battery) as a load,
LEDR Light-emitting device as an indicator of battery level and battery status

Claims (11)

The power transmission device of the non-contact power transmission system that electromagnetically couples the primary coil and the secondary coil to transmit power from the power transmission device to the power reception device and supplies power to the main load of the power reception device. A power transmission control device provided;
The power transmission device includes a first power transmission driver that drives one end of the primary coil, and a second power transmission driver that drives the other end of the primary coil,
The power transmission control device has a power transmission side control circuit that controls the operation of the power transmission device,
The power transmission side control circuit is:
A failure detection circuit that monitors a coil end voltage, which is a voltage of at least one of the one end and the other end of the primary coil, and detects a failure of the first power transmission driver and the second power transmission driver; ,
When the coil end voltage is not a coil end voltage corresponding to an input signal of the first power transmission driver or the second power transmission driver, the failure detection circuit includes the first power transmission driver or the second power transmission driver. A power transmission control device that determines that a power transmission driver is out of order. The power transmission control device according to claim 1,
The failure detection circuit monitors the coil end voltage in a state where the first power transmission driver and the second power transmission driver normally drive the primary coil, and detects the first power transmission driver or the first power transmission driver. A power transmission control device that detects a failure during normal driving of the power transmission driver of No. 2. The power transmission control device according to claim 1 or 2,
A first test driver for driving the one end of the primary coil; and a second test driver for driving the other end of the primary coil;
The power transmission side control circuit performs normal input of each input signal of the first power transmission driver or the second power transmission driver before the primary coil is normally driven by the first power transmission driver and the second power transmission driver. The level is a level at which the one end or the other end of the primary coil is in a floating state,
In that state, the one end or the other end of the primary coil is driven by the first test driver or the second test driver,
When the coil end voltage is not a coil end voltage corresponding to a drive output level of the first test driver or the second test driver, the failure detection circuit may It is determined that an initial failure has occurred in the second power transmission driver. The power transmission control device according to claim 3,
A first capacitor and a second capacitor are connected in series to the primary coil to form a series resonant circuit,
The power transmission side control circuit, when performing initial failure detection,
The one end and the other end of the primary coil are complementarily driven by the first test driver and the second test driver,
The failure detection circuit monitors voltage fluctuations due to an AC component flowing through the first capacitor and the second capacitor, and determines whether the first capacitor or the second capacitor is detected depending on whether a predetermined voltage fluctuation is detected. A power transmission control device that detects an initial failure of a capacitor of No. 2. A power transmission control device according to claim 3 or claim 4, wherein
Each of the first test driver and the second test driver has first and second transistors of different conductivity types and a current limiting resistor connected in series between power supply voltages. A power transmission control device. A power transmission control device according to any one of claims 3 to 5,
A series capacitor is configured by connecting a first capacitor and a second capacitor to the primary coil,
The power transmission side control circuit charges the first capacitor or the second capacitor with the first test driver or the second test driver, and then charges the first power transmission driver and the second capacitor. A power transmission control device, wherein normal driving of the resonance circuit by a power transmission driver is started. A power transmission control device according to any one of claims 1 to 5,
A timing control circuit for controlling the operation timing of the power transmission device;
The power transmission device includes a first switch circuit for transmitting a coil end voltage at one end of the primary coil to the failure detection circuit at a desired timing, and a coil end voltage at the other end of the primary coil. A second switch circuit for transmitting to the failure detection circuit at a desired timing,
The timing control circuit includes:
In the latter half of the low-level driving period or the high-level driving period of the one end of the primary coil by the first power transmission driver or the first test driver, the first switch circuit is turned on, and the primary The coil end voltage at one end of the coil is transmitted to the failure detection circuit,
In the latter half of the low level driving period or the high level driving period of the other end of the primary coil by the second power transmission driver or the second test driver, the second switch circuit is turned on, Transmitting the coil end voltage of one end of the next coil to the failure detection circuit;
A power transmission control device. A non-contact power transmission system that electromagnetically couples a primary coil and a secondary coil to transmit power from a power transmission device to a power reception device and supplies power to the main load of the power reception device,
The power transmission device is:
A first power transmission driver that drives one end of the primary coil; and a second power transmission driver that drives the other end of the primary coil;
The power transmission control device has a power transmission side control circuit that controls the operation of the power transmission device,
The power transmission side control circuit is:
A failure detection circuit that monitors a coil end voltage, which is a voltage of at least one of the one end and the other end of the primary coil, and detects a failure of the first power transmission driver and the second power transmission driver; ,
The failure detection circuit monitors the coil end voltage when the first power transmission driver and the second power transmission driver are normally driven, and the coil end voltage is the first power transmission driver or the first power transmission driver. When the coil end voltage does not correspond to the input signal of the second power transmission driver, it is determined that the first power transmission driver or the second power transmission driver has failed, and power transmission to the power receiving device is stopped. ,
In addition, the power receiving device
A power receiving unit including a rectifier circuit that rectifies the dielectric voltage of the secondary coil;
A load modulator for data transmission from the power receiving device to the power transmitting device;
A power supply control unit for controlling power supply to the main load;
A non-contact power transmission system comprising: The contactless power transmission system according to claim 7,
The power transmission device is:
A first test driver for driving the one end of the primary coil;
A second test driver for driving the other end of the primary coil;
The power transmission side control circuit performs normal input of each input signal of the first power transmission driver or the second power transmission driver before the primary coil is normally driven by the first power transmission driver and the second power transmission driver. The level is set to a level at which the one end or the other end of the primary coil is in a floating state, and in this state, the one end of the primary coil or the one end of the primary coil is set by the first test driver or the second test driver. Driving the other end,
The failure detection circuit is configured such that the voltage at the one end or the voltage at the other end of the primary coil is not a voltage corresponding to the drive output level of the first test driver or the second test driver. The first power transmission driver or the second power transmission driver determines that an initial failure has occurred and stops power transmission.
A contactless power transmission system. A power transmission control device according to any one of claims 1 to 7,
A power transmission unit including the first and second power transmission drivers for driving the primary coil;
A power transmission device comprising:   An electronic device comprising the power transmission device according to claim 10.

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