JP4930093B2 - Power transmission control device, power reception control device, non-contact power transmission system, power transmission device, power reception device, and electronic equipment - Google Patents

Description

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

  In recent years, contactless power transmission (non-contact power transmission) that uses electromagnetic induction and enables power transmission even without a contact of a metal part has been in the spotlight. As an application example of this non-contact power transmission, charging of a mobile phone or a household device (for example, a handset of a phone) 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 a conventional non-contact power transmission system, a power receiving device corresponding to a predetermined load condition is provided, and a power transmitting device capable of transmitting power to the power receiving device under the best conditions is required. In the power transmission device, the drive frequency and the impedance of the power transmission unit are adjusted so that the best power transmission characteristics can be obtained when combined with the power reception device.

  However, a power transmission device and a power reception device that can adjust the characteristics of power transmission and power reception are also conventionally known.

  In Patent Document 2, when the main load on the power receiving device side is changed, the characteristics of both the power transmitting device and the power receiving device are changed. When designing a plurality of types of contactless power transmission devices corresponding to different loads, In addition, in view of the fact that the development period becomes longer, a power adjustment unit is provided in the power receiving apparatus so that the characteristics of the power receiving apparatus can be adjusted, thereby shortening the development period.

In Patent Document 3, a plurality of small power feeding coils are provided in a power transmission device, and the number of small power feeding coils to be used is adaptively switched in response to load fluctuations, thereby adapting to load fluctuations. A drive circuit is provided for each small power feeding coil.
JP 2006-60909 A Japanese Patent Laid-Open No. 10-12467 JP 2005-210801 A

  Contactless power transmission systems are expected to be widely used in a wide variety of fields. In order to meet such needs, a power transmission device that can flexibly handle various devices on the power receiving device side with a single power transmission device is required.

  For example, when the non-contact power transmission system is used for charging a secondary battery (main load), examples of devices on which the secondary battery is mounted include portable phones such as mobile phone terminals, PDA terminals, and portable computer terminals. Although a terminal is assumed, there is also a possibility that it may be applied to charging a secondary battery mounted on a digital camera, a wristwatch, or the like.

  In order to deal with a wide variety of devices with a single power transmission device, it is necessary to finely adjust the transmitted power with high accuracy on the power transmission device side. However, the conventional non-contact power system cannot finely adjust the transmission power over a wide range with high accuracy.

  For example, in the technique of Patent Document 3, a drive circuit is provided for each of three small power supply coils (primary coils), and the transmission power is switched by selecting the number of small power supply coils that are actually used.

  However, this method is a method of roughly switching the transmission power in units of the number of small power supply coils, and is not a method suitable for finely adjusting the transmission power with high accuracy. Further, in order to finely switch the transmission energy, it is necessary to increase the number of small power supply coils, and the number of drive circuits is increased accordingly. Therefore, it cannot be denied that the circuit scale and power consumption increase.

  Also, in the conventional non-contact power transmission system, even if a common power transmission device tries to support a plurality of completely different devices on the power receiving device side, the rated power on the power receiving device side is unknown, so the optimum power transmission power is identified. Can not do it. Therefore, excessive power may be transmitted to the power receiving apparatus.

  The present invention has been made based on such considerations, and the object thereof is to adapt the transmitted power of one power transmission device to the rated power of the device on the power receiving device side with a simple configuration that is easy to realize. The goal is to be able to make flexible adjustments and flexibly handle a wide variety of devices.

  (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 non-contact power transmission system that supplies power, the power transmission device including an LC resonance circuit having a variable resonance characteristic including the primary coil as a component, The LC resonance circuit includes at least one of at least one sub capacitor and at least one sub coil whose active state / inactive state is selected by an enable signal, and the power transmission control device controls the power transmission side to control the power transmission device The power transmission side control circuit includes a circuit, and each of the at least one sub-capacitor or the at least one sub-coil is Selectively an active state by Buru signal, thereby controlling the resonance characteristics of the LC resonant circuit.

  The LC resonance circuit on the primary side (power transmission device) has at least one of a sub-capacitor and a sub-coil, and the active state / inactive state of the sub-capacitor and the sub-coil is selectively switched by an enable signal, and the resonance characteristics of the LC resonance circuit The power transmission energy is adjusted (optimized) by changing. The transmission power from the power transmission device side depends on the resonance characteristics of the LC resonance circuit including a primary coil and a capacitor as components. For example, even when the transmission frequency is maintained at f1, if the resonance frequency (resonance peak) of the resonance circuit changes, the distance between f1 and the resonance frequency (resonance peak) changes, and as a result, the transmission power changes. To do. In this mode, by switching the active state / inactive state of the sub-capacitor and sub-coil, the resonance capacitance is controlled by changing the substantial capacitance value of the capacitor of the LC resonance circuit and the substantial inductance of the coil. Thus, the maximum transmission power is adjusted to match the rated power on the power receiving device side. Here, the terms “main” and “sub” are relative. For example, “a capacitor required to achieve one transmission power level” is “main capacitor”, and “a capacitor other than the main capacitor used to achieve another transmission power level” is “sub capacitor”. The concept of “main” and “sub” is a relative concept based on the premise of switching the transmission power level. The “active state / inactive state of the sub-capacitor or sub-coil” means “the sub-capacitor or sub-coil becomes or does not become a constituent element of the LC resonance circuit”. However, it is / is not electrically connected to the main coil (main coil). By providing an appropriate number of sub-capacitors and sub-coils and switching each active / inactive state, the resonance characteristics of the LC resonant circuit can be finely controlled over a wide range. In addition, the transmission power can be adjusted by changing the resonance characteristics of the LC resonance circuit while maintaining the transmission frequency constant. Not switching the power transmission frequency contributes to the reduction of unnecessary radiation noise, and the effect of facilitating the countermeasure is also obtained.

  (2) In another aspect of the power transmission control device of the present invention, the power transmission device is provided corresponding to the at least one sub-capacitor, and at least one of which an active state / inactive state is selected by the enable signal. Has two sub power transmission drivers.

  An example of a specific configuration for controlling the active state / inactive state of the sub-capacitor will be clarified. That is, in this aspect, a sub power transmission driver is provided for each sub capacitor, and the active state / inactive state of the sub power transmission driver is switched by an enable signal. Since it is easy to configure a sub power transmission driver with an enable terminal and the circuit configuration is hardly complicated, there is an advantage that the resonance characteristics of the LC resonant circuit can be adjusted by a compact configuration, and it can be realized. Easy.

  (3) In another aspect of the power transmission control device of the present invention, the power transmission device includes at least one switch provided on at least one of the at least one sub-capacitor and controlled to be turned on / off by the enable signal. It has a circuit.

  Another example of a specific configuration for controlling the active state / inactive state of the sub-capacitor will be clarified. That is, in this aspect, a switch circuit is provided for each sub-capacitor (specifically, a switch circuit is connected in series to the sub-capacitor), and the switch circuit is turned on / off by an enable signal. Switches between active and inactive states. The switch circuit is an analog switch using a MOS transistor, for example. It is easy to configure the switch circuit, and the circuit configuration is hardly complicated. Therefore, there is an advantage that the resonance characteristic of the LC resonance circuit can be adjusted by a compact configuration, and it is easy to realize.

  (4) In another aspect of the power transmission control device of the present invention, the at least one sub-capacitor is provided in parallel to the main capacitor of the LC resonance circuit.

  By activating a sub capacitor provided in parallel to the main capacitor, the capacitance of the sub capacitor in the active state is added to the capacitance of the main capacitor, thereby adjusting the resonance characteristics of the LC resonance circuit. Is done.

  (5) In another aspect of the power transmission control device of the present invention, the power transmission control device includes at least one sub power transmission driver provided corresponding to the at least one subcoil, wherein an active state / inactive state is selected by the enable signal. .

  An example of a specific configuration for controlling the active state / inactive state of the subcoil is clarified. That is, in this aspect, a sub power transmission driver is provided for each sub coil, and the active state / inactive state of the sub power transmission driver is switched by an enable signal. Since it is easy to configure a sub power transmission driver with an enable terminal and the circuit configuration is hardly complicated, there is an advantage that the resonance characteristics of the LC resonant circuit can be adjusted by a compact configuration, and it can be realized. Easy.

  (6) In another aspect of the power transmission control device of the present invention, the at least one subcoil is provided in series with the main coil of the LC resonance circuit.

  When the subcoil becomes a component of the LC resonance circuit, it is clarified that the subcoil is connected in series with the main coil.

  (7) In another aspect of the power transmission control device of the present invention, each of the plurality of lead lines is drawn from each of a plurality of different positions of the planar coil having a predetermined pattern, and corresponds to at least one of the lead lines. The sub power transmission driver is provided.

  The main coil and at least one subcoil are not formed as separate coils, but are formed by dividing a common planar coil. That is, each of a plurality of lead wires is drawn from each of a plurality of positions of a common planar coil, and a sub power transmission driver is provided corresponding to at least one lead wire, and the active state / inactive state of the sub power transmission driver Is used to select a common planar coil drawing position, thereby adjusting the inductance of the coil. With a simple configuration, various coil inductances can be realized.

  (8) In another aspect of the power transmission control device of the present invention, before normal power transmission is started, an authentication process based on authentication information transmitted from the power receiving device is executed to determine whether power transmission is possible, and power transmission is possible. The power transmission side control device, based on at least a part of the authentication information, the active signal / inactive of the plurality of capacitors or the plurality of coils according to the enable signal. The state is selected to adjust the resonance characteristics of the LC resonance circuit, and the maximum transmission power during the power transmission is controlled so as to match the rated power on the power receiving apparatus side.

  Before starting normal power transmission, authentication is performed based on authentication information sent from the power receiving device, and it is determined whether the device on the power receiving device is a device that can be a power transmission target, and at least a part of the authentication information. Based on the above, the rated power on the power receiving device side (that is, the rated power of at least one of the power receiving device and the device on which the power receiving device is mounted) is identified, and the maximum transmission power on the power transmitting device side matches the rated power on the power receiving device side Normal power transmission. Through the authentication process, the power transmission device side can acquire information on the power reception device side to determine whether or not power transmission is possible, and thus can support a wide variety of devices. There is no need to prepare a power transmission device for each power receiving device, and the primary side device and the secondary side device can be flexibly combined. Further, since excessive power is not transmitted to the device on the power receiving device side, safety in the device on the power receiving device side is ensured. In addition, since excessive power is not transmitted to the device on the power receiving device side, the ratings (voltage rating and current rating) of the components on the power receiving device side can be lowered, thereby reducing costs. Can do. Further, since the authentication information is effectively used, it is not necessary to transmit special information for determining the maximum transmission power from the power receiving apparatus side to the power transmitting apparatus side, and the communication processing can be simplified.

  (9) In another aspect of the power transmission control device of the present invention, the authentication information includes rated power information on the power receiving device side, and the power transmission side control circuit performs the LC based on the rated power information. The resonance characteristic of the resonance circuit is adjusted to control the maximum transmission power during the power transmission.

  The authentication information includes the rated power information on the power receiving device side. Since the rated power information can be acquired directly on the power transmission device side, the maximum transmission power can be easily adjusted.

  (10) In another aspect of the power transmission control device of the present invention, the authentication information includes resonance characteristic information of a resonance circuit including the primary coil as a component, and the power transmission side control circuit includes the resonance characteristic. Based on the information, the resonance characteristic of the LC resonance circuit is adjusted, and the maximum transmission power during the power transmission is controlled.

  The authentication information includes the resonance characteristic information of the resonance circuit. The resonance characteristic information is, for example, information on the resonance frequency to be used, or information on the inductance value of the LC resonance circuit to be used and the capacitance value of the capacitor. Based on this resonance characteristic information, the power transmission device side can realize the resonance characteristic of the resonance circuit desired by the power reception device side, and can execute power transmission under the optimum conditions.

  (11) In another aspect of the power transmission control device of the present invention, when the power transmission side control circuit receives a signal requesting power saving power transmission having lower transmission power than that during normal power transmission from the power reception device, the resonance circuit The power saving power transmission is executed at the same frequency as the power transmission frequency.

  The function of controlling the transmission power without changing the transmission frequency of the present invention is applied to “power save transmission”. “Power-saving power transmission” is continuous power transmission with lower power than normal power transmission. For example, when charging of the main load (secondary battery) on the power receiving apparatus side is completed, if power transmission from the power transmission apparatus is completely stopped, the main load (secondary battery) cannot be recharged (that is, for example, When the state where the portable device or the like is set on the charging stand continues, the fully charged main load (secondary battery) is discharged and needs to be charged again with time. In this case, Although it is necessary to resume charging, if normal power transmission is stopped together with full charging, it becomes impossible to detect the necessity of recharging on the power receiving device side). Therefore, even after the main load (secondary battery) becomes fully charged, continuous power transmission (that is, power save transmission) with weak power is continued, and charging control of the main load (secondary battery) on the power receiving device side is continued. It is desirable to keep the function on so that when recharging is necessary, it can be detected and immediately returned to normal power transmission. However, in order to realize power-saving power transmission, for example, if the transmission frequency is changed, there is no possibility that some influence will be exerted on surrounding equipment with the change of the frequency (for example, transmission frequency) Is not completely free of unwanted radiation noise). Therefore, while maintaining the same frequency as that during normal power transmission, L and C of the LC resonance circuit are variably changed, and as a result, the frequency difference between the resonance frequency (resonance peak) and the transmission frequency is increased. Transmission power can be reduced. As a result, it is possible to switch to power saving power transmission without changing the transmission frequency. Since the transmission frequency is constant, for example, there is no concern about the problem of unnecessary radiation noise.

  (12) In one aspect of the contactless power transmission system of the present invention, the primary coil and the secondary coil are electromagnetically coupled to transmit power from the power transmission apparatus to the power reception apparatus, and to the main load of the power reception apparatus A non-contact power transmission system for supplying power to the power transmission device, wherein the power transmission device includes an LC resonance circuit having a variable resonance characteristic including the primary coil as a component, and the LC resonance circuit is controlled by an enable signal. Including at least one of at least one sub-capacitor and at least one sub-coil in which an active state / inactive state is selected, the power transmission control device includes a power transmission side control circuit that controls the power transmission device, and the power reception device includes: A power receiving side control including a load modulation unit for transmitting a signal to the power transmitting device, and a power receiving side control circuit for controlling the power receiving device. The path includes information for controlling the operation of the load modulation unit at the time of authentication before starting normal power transmission, and causing the power receiving apparatus to control transmission power during normal power transmission to the power receiving apparatus. Authentication information is transmitted by load modulation, and the power transmission side control circuit of the power transmission apparatus executes authentication processing based on the authentication information transmitted from the power reception apparatus before normal power transmission is started. And at least 1 based on the information included in the authentication information for causing the power receiving device to control the transmission power during normal power transmission. Each of the sub-capacitors or the at least one sub-coil is selectively activated by the enable signal to control the resonance characteristics of the LC resonant circuit, , To conform to the rated power of the power reception device, to control the maximum transmission power during the normal power transmission.

  In the non-contact power transmission system of this aspect, based on the authentication information from the power receiving device side, the power transmission device side authenticates the device and changes the resonance characteristics of the LC resonance circuit by selecting the sub capacitor and the sub coil. Appropriate power transmission is possible because the transmission power is adjusted (without excessive power transmission). Therefore, a single power receiving device can support a wide variety of devices on the power transmission device side. It becomes possible.

  (13) The contactless power transmission system according to the present invention, wherein the power receiving side control circuit monitors the state of the main load during normal power transmission, and the main load does not require power transmission during normal power transmission. When a state is reached, the power transmission device transmits a signal requesting power saving power transmission, which is lower power transmission than that during normal power transmission, and the power transmission side control circuit transmits the power saving device from the power receiving device. When a signal requesting power transmission is received, the resonance characteristic of the resonance circuit is changed, and the power-save power transmission at the same frequency as that during power transmission is executed.

  In the non-contact power transmission system of this aspect, the power receiving device side monitors the state of this load and transmits a signal requesting power saving power transmission to the power transmission device side, and the power transmission device changes the resonance characteristics of the resonance circuit, Shift to power save transmission while maintaining the transmission frequency during normal power transmission. Therefore, power-saving power transmission, which is continuous power transmission using weak power, can be realized without difficulty, and the transmission frequency can be kept constant. For example, there is no concern that unnecessary radiation noise will occur.

  (14) In one aspect of the power transmission device of the present invention, a primary coil that is a component of the LC resonance circuit, and at least one of the at least one sub capacitor and the at least one sub coil included in the LC resonance circuit, And at least one sub power transmission driver provided corresponding to the at least one sub capacitor, wherein an active state / inactive state is selected by the enable signal.

  In the power transmission device of this aspect, a sub power transmission driver is provided corresponding to the sub capacitor and the sub coil, and the resonance characteristics of the LC resonance circuit are changed by switching the active state / inactive state of the sub power transmission driver so that the same frequency is obtained. To achieve different transmission power levels.

  (15) In another aspect of the power transmission device of the present invention, a primary coil that is a component of an LC resonance circuit, at least one sub-capacitor included in the LC resonance circuit, and at least one of the at least one sub-capacitor And at least one switch circuit that is on / off controlled by the enable signal.

  In the power transmission device of this aspect, a switch circuit is provided corresponding to the sub capacitor and the sub coil, and the resonance characteristics of the LC resonance circuit are changed by switching the active state / inactive state of the switch circuit, so that they differ at the same frequency. Realize transmission power level.

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

  As a result, it is possible to obtain a power supply-side electronic device (such as a cradle for charging a portable terminal) that can handle a wide variety of electronic devices.

  As described above, according to the present invention, the transmission power of one power transmission device can be flexibly adjusted to match the rated power of the device on the power reception device side with a simple and easy-to-implement configuration. It is possible to flexibly handle various devices. The convenience of the non-contact power transmission system is greatly improved by the present invention. Therefore, the use promotion of the non-contact power transmission system can be promoted, and the non-contact power transmission system can be widely spread as a social infrastructure.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
Note that this embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in this embodiment are indispensable as means for solving the present invention. Not always.

(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, and FIG. 1A is a diagram illustrating an example of an electronic device to which a contactless power transmission technique is applied. FIG. 1B is a diagram for explaining the principle of contactless 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 40, 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 composed of, for example, a crystal oscillation circuit and generates a primary 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. Regarding the position detection circuit 56, the divided voltage VD4 serves as a signal input (ADIN) for frequency detection.

  The load modulation unit 46 performs load modulation processing. Specifically, when transmitting desired data from the power receiving device 40 to the power transmitting device 10, the load at the load modulation unit 46 (secondary side) is variably changed according to the transmission data, and the primary coil L1 The signal waveform of the induced voltage is changed. 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 secondary side is set to a low load (high impedance) 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 secondary side is set to a high load (low impedance) in order 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 power receiving device 40 side from the voltage output node NB7 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 a CR oscillation circuit, for example, and generates a secondary 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.

(Operation during authentication)
Next, an authentication operation before normal power transmission and an operation for adjusting the maximum transmission power will be described. 4 (A), 4 (B), and 4 (C) are diagrams for explaining an example of the authentication operation and the maximum transmission power adjustment operation. FIG. 4 (A) shows the authentication information. It is a figure which shows a mode that adjustment of maximum transmission power is performed based on FIG. 4, FIG.4 (B) and FIG.4 (C) are figures which respectively show the specific example of authentication information.

  As illustrated in FIG. 4A, the power receiving device 40 transmits an authentication frame (SR) to the power transmitting device 10 at the time of authentication before normal power transmission. The authentication frame (SR) is transmitted by load modulation by the load modulation unit 46.

  “Authentication information” is “a general term for information transmitted from the power receiving device 40 to the power transmission device 10 during authentication”, and an authentication frame (SR) is also authentication information. As shown in FIGS. 4B and 4C, the authentication frame (SR) includes a start code 1, a manufacturer ID 2, and a manufacturer product ID 3.

  The manufacturer ID 2 is information for specifying the manufacturer of the device on the power receiving device side (at least one of the power receiving device and the electronic device), and the manufacturer product ID 3 is the device on the power receiving device side (at least one of the power receiving device and the electronic device). ) (For example, a code indicating the product type or model number). With this information, the power transmission device 10 can identify which manufacturer and which product the device on the power receiving device 40 side is. If the device on the power receiving device 40 side can be specified, it is possible to determine whether the device on the power receiving device 40 side can be a target of normal power transmission (that is, authentication).

  In FIG. 4B, the authentication frame (SR) further includes rated power information 4. The rated power information 4 is information indicating the rated power of the device on the power receiving device side (at least one of the power receiving device and the electronic device). When the normal power transmission is permitted as a result of the authentication process, the power transmission device 10 next adjusts the maximum transmission power during normal power transmission based on the rated power information 4 so as to conform to the rated power ( In general, the maximum transmission power is adjusted to the rated power value).

  In FIG. 4C, resonance characteristic information 5 is included instead of the rated power information. The resonance characteristic information is, for example, information on the resonance frequency to be used, or information on the inductance value of the LC resonance circuit to be used and the capacitance value of the capacitor. With this resonance characteristic information 5, the power transmission device 10 side can realize the resonance characteristic of the resonance circuit desired by the power reception device 40, and can execute power transmission under optimum conditions.

  In FIG. 4A, PT indicates transmission power whose maximum transmission power is controlled by the power transmission device 10. Since the authentication frame (SR) in FIGS. 4B and 4C includes the rated power information 4 and the resonance characteristic information 5, the power transmission device 10 side realizes the optimum maximum transmission power. Necessary information can be obtained directly, and therefore transmission power can be easily controlled.

  5A and 5B are diagrams for explaining another example of the authentication operation and the maximum transmission power adjustment operation. FIG. 5A shows the maximum transmission based on the authentication information. It is a figure which shows a mode that electric power adjustment is performed, and FIG.5 (B) is a figure which shows the specific example of authentication information.

  As shown in FIG. 5A, the power transmission device 10 is provided with a memory (ROM) 11 that stores transmission power setting information 11. The transmission power setting information 11 is, for example, table information in which a device on the power receiving device 40 side and rated power information are associated with each other on a one-to-one basis.

  The authentication frame (SR) shown in FIG. 5B includes a start code 1, a manufacturer ID 2 and a manufacturer product ID 3, but the rating information 4 and the like shown in FIGS. The resonance characteristic information 5 is not included. That is, the power receiving device 10 can only specify the device on the power receiving device 40 side, and cannot directly acquire information for adjusting the transmission power. Therefore, the power transmission device 10 uses the transmission power setting information 11 (for example, table information in which the devices on the power reception device 40 side and the rated power information are associated one-to-one) stored in the memory (ROM) 11. Then, the rated power information of the device on the power receiving device 40 side is acquired, and based on this, the maximum transmission power is optimized.

(Method to increase or decrease the transmission power while changing the resonance characteristics of the LC resonance circuit and fixing the transmission frequency)
Next, a method for increasing or decreasing the transmission power while fixing the transmission frequency by changing the resonance characteristic (resonance frequency) of the LC resonance circuit will be described. FIG. 6 is a diagram illustrating a mode in which different power is transmitted at the same transmission frequency by properly using a plurality of resonance characteristics having different resonance frequencies.

  In FIG. 6, QL1, QL4, and QL5 all show the resonance characteristics of the LC resonance circuit including the primary coil (L1, etc.) and the capacitors (C1, C2, etc.), but each has a different resonance frequency. Yes. The resonance frequency of QL1 is f0, the resonance frequency of QL4 is f6, and the resonance frequency of QL5 is f4.

  The resonance characteristics of QL1, QL4, and QL5 are realized by changing the inductance value of the coil of the LC resonance circuit or the capacitance value of the capacitor. As can be seen from FIG. 6, by changing (shifting) the resonance frequency of the LC resonance circuit, the relative positional relationship (distance from the resonance frequency) with the resonance frequency changes even at the same transmission frequency f1. The transmission power can be changed. That is, by changing the resonance characteristics in the order of QL4, QL1, and QL5, the transmission power value can be sequentially changed to P5, P1, and P3. Increasing or decreasing the transmission power without changing the transmission frequency does not cause the problem of electromagnetic wave radiation and has no problem in the radio law, and is useful as a method for adjusting the actual transmission power.

  As a method of changing (shifting) the resonance frequency of the resonance circuit, there is a method of changing at least one of the capacitance value of the capacitor and the inductance value of the coil of the LC resonance circuit.

  FIG. 7 is a circuit diagram illustrating a configuration of a main part of a power transmission device capable of adjusting the transmission power by changing the resonance characteristics of the resonance circuit by changing the capacitance value of the capacitor of the resonance circuit. As illustrated, the power transmission unit 12 includes a variable capacitance unit 13. The variable capacitance section 13 is provided with two capacitance-variable capacitors C10 and C20, and the capacitance values of the capacitors C10 and C20 are controlled by a capacitance value control signal S3 of the power transmission side control circuit 22. A specific method for changing the capacitances of the capacitors C10 and C20 will be described later.

  FIG. 8 is a circuit diagram illustrating a configuration of a main part of a power transmission device capable of adjusting the transmission power by changing the resonance characteristics of the resonance circuit by changing the inductance value of the coil of the resonance circuit. The primary coil (L10) shown in FIG. 8 is a coil having a variable inductance value, and the inductance value is controlled by an inductance value control signal S4 of the power transmission side control circuit 22. A specific method for changing the inductance value of the primary coil (L10) will be described later.

(Example of specific method for changing resonance characteristics of LC resonance circuit)
FIG. 9 is a circuit diagram illustrating an example of a specific circuit configuration of a power transmission device that changes the resonance characteristics of the LC resonance circuit using a sub capacitor. In FIG. 9, the same reference numerals are given to the parts common to the previous figures.

  The power transmission unit 12 includes a primary coil (L1), a plurality of capacitors (C1 to C4), and power transmission drivers (DR1 to DR4). Since the capacitors (C1, C2) are capacitors necessary for configuring a normal LC resonance circuit, they are referred to as “main capacitors” here for convenience. On the other hand, since the capacitors (C3, C4) have a function of adjusting the resonance characteristics of the LC resonance circuit, they are referred to as “sub capacitors” for convenience. However, this designation is for convenience, and the role of each capacitor is not necessarily limited to that designation.

  That is, one pole of three capacitors (C1, C3, C4) is connected to the upper end of the primary coil L1, but all of these three capacitors (C1, C3, C4) are potentially Can function as a sub-capacitor and can also function as a main capacitor. For example, the capacitor C3 can be grasped as a main capacitor, and the capacitors (C1, C4) can be grasped as sub capacitors.

  In other words, the “capacitor necessary for realizing one transmission power level” is the “main capacitor”, and the “capacitor other than the main capacitor used for realizing other transmission power levels” is the “sub capacitor”. The concept of “main” and “sub” is a relative concept based on the premise of switching the transmission power level. In the following description, as described above, the capacitors C1 and C2 are treated as main capacitors, and the capacitors C3 and C4 are treated as sub capacitors (this is the same for the subcoil).

  In addition, each of the plurality of power transmission drivers (DR1 to DR4) is provided in the power transmission unit 12 of FIG. 9 corresponding to each of the capacitors (C1 to C4). In the following description, for convenience, the power transmission drivers (DR1, DR2) corresponding to the main capacitors (C1, C2) are referred to as “main power transmission drivers”. The power transmission drivers (DR3, DR4) corresponding to the sub capacitors (C3, C4) are referred to as “sub power transmission drivers”.

  In FIG. 9, the main power transmission driver DR1 and the sub power transmission drivers (DR3, DR4) are power transmission drivers with an enable terminal. That is, the active state / inactive state of each of the main power transmission driver DR1 and the sub power transmission drivers (DR3, DR4) is selectively switched by each of the enable signals S1 to S3. Here, the “active state / inactive state” means “the sub capacitor or sub coil is / is not a constituent element of the LC resonance circuit”. Specifically, the sub capacitor or sub coil is the main coil. It is electrically connected to (main coil).

  9 includes a power transmission side control circuit 22, a drive clock generation circuit 25, and a driver control circuit 26.

  The drive clock generation circuit 25 includes, for example, a PLL circuit, generates a drive clock having a desired frequency based on the source clock CLK from the oscillation circuit 16, and supplies the drive clock to the driver control circuit 26.

  The driver control circuit 26 has an inverter (INV1) for driving the main power transmission drivers (DR1, DR2) in reverse phase. Actually, each of the main power transmission drivers (DR1, DR2) also has a circuit for adjusting the driving timing of each transistor of the CMOS configuration so that no through current flows, but this is not shown in FIG. ing.

  The power transmission side control circuit 22 switches between the active state / inactive state of each of the main power transmission driver DR1 and the sub power transmission drivers (DR3, DR4) by each of the enable signals S1 to S3, and a desired transmission power (transmission power) PT. Is realized.

  An authentication frame (SR) signal sent from the power receiving apparatus (secondary device) is transmitted to the power transmission side control circuit 22 via the voltage detection circuit 14 and the waveform detection circuit 28. The power transmission side control circuit 22 extracts information included in the authentication frame SR (such as the rating information 4 and the resonance characteristic information 5 in FIG. 4), and generates enable signals S1 to S3 based on the information. As described above, the active signals / inactive states of the main power transmission driver DR1 and the sub power transmission drivers (DR3, DR4) are switched by the enable signals S1 to S3, whereby the desired transmission power (transmission power) PT is obtained. Realized.

  FIGS. 10A, 10 </ b> B, and 10 </ b> C are diagrams for explaining examples of driving modes of the LC resonance circuit in the power transmission device of FIG. 9. In FIG. 10A, the main power transmission driver DR1 is in an active state (that is, a state in which each capacitor is driven by a power transmission output), and the sub power transmission drivers (DR3, DR4) are in an inactive state (that is, the power transmission output terminal is high). Impedance state). Therefore, the main capacitor C1 is in an active state, and the sub capacitors C3 and C4 are in an inactive state. In the figure, IA1 indicates a drive current.

  In FIG. 10B, the main power transmission driver DR1 and the sub power transmission driver DR3 are in an active state (that is, a state in which each capacitor is driven by a power transmission output), and the sub power transmission driver DR4 is in an inactive state (that is, the power transmission output terminal is High impedance state). Therefore, the main capacitor C1 and the sub capacitor C3 are in an active state, and the sub capacitor C4 is in an inactive state. In this case, the capacitance of the capacitor constituting the LC resonance circuit is (C1 + C3). In the figure, IA1 and IA2 indicate drive currents.

  In FIG. 10C, all of the main power transmission driver DR1, the sub power transmission drivers DR3 and DR4 are in the active state (that is, the state where each capacitor is driven by the power transmission output). Therefore, all of the main capacitor C1 and the sub capacitors C3 and C4 are in the active state. In this case, the capacitance of the capacitor constituting the LC resonance circuit is (C1 + C3 + C4). In the figure, each of IA1, IA2, and IA3 indicates a drive current.

  As described above, each of the enable signals S1 to S3 can appropriately change the capacitance value of the capacitor constituting the LC resonance circuit to realize a desired transmission power level.

  FIG. 11 is a circuit diagram illustrating an example of a specific circuit configuration of the power transmission device that changes the resonance characteristics of the LC resonance circuit using the subcoil. In FIG. 11, the same reference numerals are given to the portions common to the above-mentioned drawings.

  The circuit configuration of the power transmission device in FIG. 11 is different from the circuit configuration of the power transmission device in FIG. 9 in that subcoils (LB2, LB3) are provided corresponding to the subcoils (C3, C4). Are the same.

  In FIG. 11, the subcoils (LB2, LB3) are connected in series to the primary coil (main coil) L1. Further, the inductance values of the main coil L1 and the subcoils LB2 and LB3 are different. Here, it is assumed that the inductance value of each coil is adjusted so that a desired different transmission power level is realized when each coil is used alone.

  FIGS. 12A, 12 </ b> B, and 12 </ b> C are diagrams for explaining examples of driving modes of the LC resonance circuit in the power transmission device of FIG. 11. In FIG. 12A, only the main power transmission driver DR1 is in an active state (that is, a state in which each capacitor is driven by a power transmission output), and the sub power transmission drivers (DR3 and DR4) are in an inactive state (that is, the power transmission output terminal is High impedance state). In the figure, IA4 indicates a drive current.

  In FIG. 12B, only the sub power transmission driver DR3 is in an active state (that is, a state in which each capacitor is driven by a power transmission output), and the main power transmission driver DR1 and the sub power transmission driver DR4 are in an inactive state. In the figure, IA5 indicates a drive current.

  In FIG. 12C, only the sub power transmission driver DR4 is in an active state (that is, a state in which each capacitor is driven by a power transmission output), and the main power transmission driver DR1 and the sub power transmission driver DR3 are in an inactive state. In the figure, IA6 indicates a drive current.

  As described above, each of the enable signals S <b> 1 to S <b> 3 can appropriately change the capacitance value of the con inductance composing the LC resonance circuit to realize a desired transmission power level.

(Second Embodiment)
In the present embodiment, an example of an LC resonance circuit capable of efficiently forming a plurality of coils and rationally selecting necessary coils will be described. 13A and 13B are diagrams showing a specific configuration of an LC resonance circuit using a common planar coil, and FIG. 13A is a connection pattern of the planar coil pattern and the power transmission driver. FIG. 13B is an equivalent circuit diagram.

  As shown in FIG. 13A, each of a plurality of lead lines (L10 to L13) is drawn out from each of a plurality of different positions (Q1 to Q4) of the planar coil 120 having a predetermined pattern (spiral pattern). It is. And sub power transmission driver (DR7, DR8) is provided corresponding to at least one of those leader lines (L10-L13).

  In FIG. 13A, the power transmission drivers (DR5, DR6) are main power transmission drivers, the power transmission drivers (DR7, DR8) are sub power transmission drivers, the capacitors (C5, C6) are main capacitors, and the capacitors (C7 , C8) are sub-capacitors.

  The main power transmission driver DR6 selects an active state / inactive state by the enable signal S4. Each of the sub power transmission drivers (DR7, DR8) selects an active state / inactive state by enable signals S5, S6.

  Further, the planar coil 120 is formed of, for example, a first layer (nth layer) metal wiring of the mounting substrate. The lead-out wirings L10, L11, and L13 are formed of, for example, a second layer ((n + 1) th layer) metal wiring. Such a wiring structure can be easily formed by using the multilayer wiring structure of the mounting substrate.

  As shown in FIG. 13B, when the main power transmission driver DR5 and the main power transmission driver DR6 are in the active state, the coil L20 interposed between the leading ends Q1 and Q2 is in the active state (use state). The drive current in this case is IA7.

  Further, when the main power transmission driver DR5 and the sub power transmission driver DR7 are in the active state, the coil (L20 + L21) interposed between the leading ends Q1 and Q3 is in the active state (use state). The drive current in this case is IA8.

  Further, when the main power transmission driver DR5 and the sub power transmission driver DR8 are in the active state, the coil (L20 + L21 + L22) interposed between the leading ends Q1 and Q4 is in the active state (use state). The drive current in this case is IA9.

  By dividing the common coil into a plurality of parts and selectively using them, a plurality of desired inductance values can be efficiently realized. By increasing the number of turns of the spiral planar coil, a coil having a long overall length can be formed in a compact manner, and a desired inductance value can be set with high accuracy by selecting the lead-out position. Further, by increasing the number of lead wires, the inductance value can be finely switched over a wide range.

  Thus, instead of forming the main coil and at least one subcoil as separate coils, a common planar coil is provided, and each of the plurality of lead lines is led out from each of a plurality of positions of the common planar coil, By providing a sub power transmission driver corresponding to at least one lead line and switching an active state / inactive state of the sub power transmission driver, by selecting a common planar coil lead position, various inductance values can be obtained. This can be realized with a simple configuration.

(Third embodiment)
In the present embodiment, a switch circuit (for example, an analog switch) is used for switching the active state / inactive state of the sub capacitor. FIG. 14 is a circuit diagram showing an example in which the active state / inactive state of the sub capacitor is selected by an analog switch.

  In FIG. 14, a switch circuit SW1 is inserted between the sub power transmission driver DR3 and the sub capacitor C3. The switch circuit SW1 is configured by an analog switch AN1 (and an inverter INV2). On / off of the analog switch AN1 is controlled by an enable signal S7. When the analog switch AN1 is turned on, the sub capacitor C3 is activated, and when the analog switch AN1 is turned off, the sub capacitor C3 is deactivated.

(Fourth embodiment)
In the present embodiment, application of the function of controlling transmission power without changing the transmission frequency to “power save transmission” will be described. Here, “power-saving power transmission” is continuous power transmission with lower power than that during normal power transmission.

  For example, in FIG. 2, when charging of the main load 90 (secondary battery 94) on the power receiving device 40 side is completed, if power transmission from the power transmission device 10 is completely stopped, the main load 90 (secondary battery 94) is restarted. Cannot charge. That is, for example, if the state where the portable device or the like is set on the charging stand continues, the fully-charged main load 90 (secondary battery 94) is discharged and needs to be recharged over time, In this case, charging needs to be restarted. However, if normal power transmission is stopped together with full charging, it becomes impossible to detect the necessity of recharging on the power receiving device side.

  Therefore, even after the main load 90 (secondary battery 94) is in a fully charged state, continuous power transmission (that is, power save power transmission) with weak power is continued, and the charging control device for the main load 90 on the power receiving device 40 side. 92 is maintained in the operating state.

  That is, by always transmitting the minimum electric power necessary for managing the charging of the secondary battery 94, when recharging becomes necessary, the charging control device 92 immediately detects that fact. Start recharging. As a result, a large load current flows, so that the load viewed from the power receiving device 10 side increases, and the voltage of a single part of the primary coil (L1) increases, which is the voltage detection circuit 14 and the waveform detection circuit 28 (FIG. ). When the power transmission side control circuit 22 included in the power transmission control device 20 detects that the load on the power receiving device 40 side suddenly increases during power save power transmission, the power transmission side control circuit 22 determines that recharging has started, and power save power transmission Switch to normal power transmission. In this way, the secondary battery 94 included in the main load 90 on the power receiving device 40 side can be recharged without difficulty.

  However, when switching from normal power transmission to power save power transmission, or when switching from power save power transmission to normal power transmission, switching the transmission frequency does not mean that there is no risk of unnecessary radiated noise. Legal measures are required.

  That is, it can be said that it is desirable to switch between normal power transmission and power save power transmission by changing the transmission power without changing the transmission frequency. Therefore, a method of controlling the transmission power by changing the characteristics of the resonance circuit is adopted.

  That is, as shown in FIG. 6, a method is adopted in which normal power transmission and power save power transmission are switched by increasing or decreasing the transmission power by changing (shifting) the resonance frequency of the LC resonance circuit. If the method of FIG. 6 is employ | adopted, as mentioned above, even if it is the same transmission frequency f1, relative positional relationship (distance from a resonance frequency) with a resonance frequency will change, and transmission power can be changed. That is, by changing the resonance characteristics in the order of QL4, QL1, and QL5, the transmission power value can be sequentially changed to P5, P1, and P3. For example, P1 in FIG. 6 is a transmission power value during normal power transmission, and P3 is a power value during power save transmission.

  Realizing power-save transmission by increasing or decreasing the transmission power without changing the transmission frequency does not cause the problem of electromagnetic radiation, for example, there is no need to worry about problems in the Radio Law at all. This is useful as an adjustment method.

(Fifth embodiment)
In the present embodiment, an example of a specific operation procedure of the contactless power transmission system will be described. FIG. 15 is a flowchart showing an example of a specific operation procedure of the contactless power transmission system of the present invention. In FIG. 15, the left side shows the procedure on the primary side (power receiving device side), and the right side shows the procedure on the secondary side (power transmission device side).

  First, the power transmission device 10 is activated (step ST1). The power transmission device 10 starts power transmission (for example, intermittent power transmission) for activating the power reception device 40 (step ST2).

  The power receiving device 40 is activated by the supply of power (step ST3). Next, the power receiving apparatus 40 transmits an authentication frame (authentication information) to the power transmitting apparatus 10 by load modulation (step ST4).

  The power transmission device 10 detects a load change on the power receiving device side by detecting a voltage change at the end of the primary coil (L1) by the voltage detection circuit 14 and the waveform detection circuit 28, and thereby receives an authentication frame. The received authentication frame is analyzed (step ST5).

  By analyzing the authentication frame, the power transmission device 10 specifies the device (power reception device and electronic device) on the power reception device 40 side, specifies the rated power, and transmits the transmission power (that is, the maximum transmission power) so as to match the rated power. ) Is determined (step ST6).

  And in the power transmission apparatus 10, in order to implement | achieve the determined transmitted power (maximum transmission power), the change of a resonance characteristic (FIG. 6) is performed (step ST7). Then, normal power transmission (continuous power transmission with the determined power value) is started (step ST8).

  In the figure, steps ST5 to ST7 are processing (A) for controlling transmission power using the authentication processing.

  The power receiving device 40 performs normal power receiving processing (rectification processing, power supply to the load 90, etc.) (step ST9). Then, the state of the main load 90 is monitored, and it is detected whether or not the main load 90 is in a state where electric power from normal power transmission is necessary. For example, the charge control device 92 included in the load 90 monitors the charged state of the secondary battery 94 and detects whether or not the fully charged state is reached (step ST10).

  Upon detecting full charge, power receiving device 40 transmits a save frame to power transmission device 10 by load modulation by load modulation unit 46, and notifies power transmission device 10 of the fact of full charge (step ST11). When receiving the save frame (step ST12), the power transmission device 10 executes processing for switching normal power transmission to power save power transmission.

  That is, by reducing the power transmission frequency or changing the resonance characteristics to increase the distance from the resonance frequency (resonance peak), the transmission frequency is kept the same as during normal power transmission. Then, the transmission power is adjusted to power saving power transmission (step ST13).

  And power saving power transmission is performed (step ST14). The power receiving apparatus 40 performs a power save power receiving operation (rectifying operation or a power supply operation with a minimum power enough to maintain the charge monitoring function for the main load 90) (step ST15).

  Steps ST11 to ST13 are processing (B) that realizes power-save power transmission by reducing the transmission power without changing the transmission frequency.

  As described above, according to the present invention, a single power transmission device can be used for a variety of devices on the power receiving device side, and can be applied to perform power save power transmission without changing the transmission frequency. Therefore, the convenience (usability) of the wireless point power transmission system can be greatly improved.

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) By providing an appropriate number of sub-capacitors and sub-coils and switching each active / inactive state with an enable signal, the resonance characteristics of the LC resonance circuit can be finely controlled over a wide range.
(2) The transmission power can be adjusted by changing the resonance characteristics of the LC resonance circuit while keeping the transmission frequency constant. That is, instead of changing the transmission frequency, it is possible to change the transmission power by changing the distance between the transmission frequency and the resonance frequency (resonance peak). Not switching the power transmission frequency contributes to the reduction of unnecessary radiation noise, and the countermeasures are easy.
(3) It is easy to provide a sub-capacitor and a sub-coil, to provide a sub power transmission driver with an enable terminal, to provide an analog switch circuit, etc. With a simple configuration, there is an advantage that the resonance characteristics of the LC resonance circuit can be adjusted, which is easy to realize.
(4) By adopting a method of adjusting the coil inductance by selecting a common planar coil drawing position, various coil inductances can be realized with a simple configuration.
(5) The function of the present invention for controlling transmission power without changing the transmission frequency can also be applied to power save transmission (continuous transmission with lower power than normal transmission).
(6) With a simple and easy-to-implement configuration, the transmission power of one power transmission device can be flexibly adjusted to match the rated power of the device on the power receiving device side, and it can flexibly handle a wide variety of devices. Can be able to.
(7) The convenience of the non-contact power transmission system is greatly improved. Therefore, the use promotion of the non-contact power transmission system can be promoted, and the non-contact power transmission system can be widely spread as a social infrastructure.

  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. It is possible to freely modify the sub-capacitor and the sub-coil in combination or to activate a plurality of sub-coils simultaneously.

  Further, the configuration and operation of the power transmission control device, the power transmission device, the power reception control device, the power reception device, and the method of detecting the load on the secondary side on the primary side are not limited to those described in the present embodiment, and various modifications are possible. Implementation is possible.

  The present invention has the effect that various electronic devices on the power receiving device side can safely use the common electronic device on the power transmission side and contribute to the expansion of the use of the non-contact power transmission system, and therefore It can be used as a power transmission control device (power transmission control IC), a contactless power transmission system, a power transmission device (IC module, etc.), and an electronic device (mobile terminal, charger, 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 primary device and the secondary device. 4A, 4B, and 4C are diagrams for explaining an example of the authentication operation and the maximum transmission power adjustment operation. 5A and 5B are diagrams for explaining another example of the authentication operation and the maximum transmission power adjustment operation. The figure which shows the aspect which transmits different electric power with the same transmission frequency by using properly the several resonance characteristic from which the resonance frequency differs The circuit diagram which shows the structure of the principal part of the power transmission apparatus which can adjust transmission power by changing the resonance characteristic of a resonance circuit by changing the capacitance value of a capacitor The circuit diagram which shows the structure of the principal part of the power transmission apparatus which adjusts transmission power by changing the resonance characteristic of a resonance circuit by changing the inductance value of a coil The circuit diagram which shows an example of the concrete circuit structure of the power transmission apparatus which changes the resonance characteristic of LC resonance circuit using a sub capacitor FIGS. 10A, 10B, and 10C are diagrams for explaining examples of driving modes of the LC resonance circuit in the power transmission device of FIG. 9, respectively. The circuit diagram which shows an example of the concrete circuit structure of the power transmission apparatus which changes the resonance characteristic of LC resonance circuit using a subcoil 12A, 12B, and 12C are diagrams for explaining examples of driving modes of the LC resonance circuit in the power transmission device of FIG. 13A and 13B are diagrams showing a specific configuration of an LC resonance circuit using a common planar coil. Circuit diagram showing an example of selecting an active / inactive state of a sub capacitor by an analog switch The flowchart which shows an example of the specific operation | movement procedure of the non-contact electric power transmission system of this invention.

Explanation of symbols

L1 primary coil (main coil), L2 secondary coil, 1 start code,
2 Manufacturer ID, 3 Manufacturer product ID, 4 Rated power information, 5 Resonance characteristics information,
DESCRIPTION OF SYMBOLS 10 Power transmission apparatus, 12 Power transmission part, 13 Variable capacity part 14 Voltage detection circuit,
16 display unit, 20 power transmission control device, 22 power transmission side control circuit, 24 oscillation circuit,
25 drive clock generation 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 oscillation circuit, 60 frequency detection circuit, 62 full charge detection circuit,
90 load of secondary side equipment, 92 charge control device (charge control IC),
94 Battery (secondary battery) as the main load
LEDR Light-emitting device as an indicator of remaining battery power and battery status,
C10, C20 Variable capacitors constituting the resonance circuit,
L10 Coil with variable inductance value,
DR1, DR2 main power transmission driver, DR3, DR4 sub power transmission driver,
C1, C2 main capacitor, C3, C4 sub capacitor,
S1-S4 enable signal, LB2, LB3 subcoil, SW1 switch circuit,
AN1 analog switch, INV1, INV2 inverter

Claims (15)

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 is:
An LC resonance circuit having a variable resonance characteristic, including the primary coil as a component;
The LC resonant circuit is:
Including at least one of at least one sub-capacitor and at least one sub-coil, wherein an active / inactive state is selected by an enable signal;
The power transmission control device includes a power transmission side control circuit for controlling the power transmission device,
The power transmission side control circuit selectively activates each of the at least one sub capacitor or the at least one sub coil by the enable signal, thereby controlling a resonance characteristic of the LC resonance circuit ,
The power transmission device is:
A power transmission control device comprising: at least one sub power transmission driver provided corresponding to the at least one sub capacitor, wherein an active state / inactive state is selected by the enable signal . The power transmission control device according to claim 1,
The power transmission device is:
A power transmission control device comprising at least one switch circuit provided in at least one of the at least one sub capacitor and controlled to be turned on / off by the enable signal. A power transmission control device according to claim 1 or 2 ,
The power transmission control device, wherein the at least one sub-capacitor is provided in parallel with a main capacitor of the LC resonance circuit. 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 is:
An LC resonance circuit having a variable resonance characteristic, including the primary coil as a component;
The LC resonant circuit is:
Including at least one of at least one sub-capacitor and at least one sub-coil, wherein an active / inactive state is selected by an enable signal;
The power transmission control device includes:
A power transmission side control circuit for controlling the power transmission device ;
At least one sub power transmission driver provided corresponding to the at least one subcoil, wherein an active state / inactive state is selected by the enable signal;
The power transmission side control circuit selectively activates each of the at least one sub-capacitor or the at least one sub-coil by the enable signal, thereby controlling a resonance characteristic of the LC resonance circuit. Power transmission control device. The power transmission control device according to claim 4 ,
The power transmission control device, wherein the at least one subcoil is provided in series with a main coil of the LC resonance circuit. The power transmission control device according to claim 4 or 5 ,
Each of a plurality of lead wires is drawn from each of a plurality of different positions of a planar coil having a predetermined pattern, and the sub power transmission driver is provided corresponding to at least one of the lead wires. Control device. A power transmission control device according to any one of claims 1 to 6 ,
Before normal power transmission is started, an authentication process based on the authentication information transmitted from the power receiving apparatus is executed to determine whether power transmission is possible, and when it is determined that power transmission is possible, the normal power transmission is performed.
The power transmission side control device selects an active state / inactive state of the plurality of capacitors or the plurality of coils by the enable signal based on at least a part of the authentication information, and sets a resonance characteristic of the LC resonance circuit. A power transmission control device that adjusts and controls the maximum transmission power during power transmission so as to conform to the rated power on the power receiving device side. The power transmission control device according to claim 7 ,
The authentication information includes rated power information on the power receiving device side, and the power transmission side control circuit adjusts a resonance characteristic of the LC resonant circuit based on the rated power information, and performs maximum transmission during power transmission. A power transmission control device that controls electric power. The power transmission control device according to claim 7 ,
The authentication information includes resonance characteristic information of a resonance circuit including the primary coil as a component, and the power transmission side control circuit adjusts the resonance characteristic of the LC resonance circuit based on the resonance characteristic information. A power transmission control device that controls the maximum transmission power during power transmission. A power transmission control device according to any one of claims 1 to 6 ,
When the power transmission side control circuit receives from the power receiving device a signal requesting power saving power transmission whose transmission power is lower than that during normal power transmission, the power transmission side control circuit changes the resonance characteristics of the resonance circuit and has the same frequency as that during power transmission. A power transmission control device that performs the power saving power transmission. 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;
Including the power receiving device,
The power transmission device is:
An LC resonance circuit having a variable resonance characteristic, including the primary coil as a component;
The LC resonant circuit is:
Including at least one of at least one sub-capacitor and at least one sub-coil, wherein an active / inactive state is selected by an enable signal;
The power transmission control device includes a power transmission side control circuit for controlling the power transmission device,
The power receiving device is:
A load modulator for transmitting a signal to the power transmission device;
A power receiving side control circuit for controlling the power receiving device,
The power receiving side control circuit controls the operation of the load modulation unit at the time of authentication before starting normal power transmission, and causes the power transmitting apparatus to control the transmission power during normal power transmission to the power receiving apparatus. Authentication information including the information of
The power transmission side control circuit of the power transmission device is:
Before starting normal power transmission, execute authentication processing based on the authentication information transmitted from the power receiving device to determine whether power transmission is possible, and start the normal power transmission when it is determined that power transmission is possible,
Each of the at least one sub-capacitor or the at least one sub-coil is selectively activated by the enable signal based on information included in the authentication information for causing the power receiving device to control transmission power during normal power transmission. As a state, control the resonance characteristics of the LC resonance circuit, thereby controlling the maximum transmission power during normal power transmission so as to match the rated power on the power receiving device side,
The power transmission device is:
A contactless power transmission system, comprising: at least one sub power transmission driver provided corresponding to the at least one sub capacitor, wherein an active state / inactive state is selected by the enable signal . The contactless power transmission system according to claim 11 ,
The power receiving side control circuit monitors the state of the main load during normal power transmission, and when the main load is in a state that does not require power transmission during normal power transmission, Send a signal requesting power save transmission, which is lower power transmission than during transmission,
When the power transmission side control circuit receives a signal requesting the power saving power transmission from the power receiving device, the power transmission side control circuit changes a resonance characteristic of the resonance circuit, and executes the power saving power transmission at the same frequency as the power transmission frequency. A contactless power transmission system characterized by The power transmission control device according to any one of claims 1 to 10 ,
A primary coil that is a component of the LC resonant circuit;
One of at least one sub-capacitor and at least one sub-coil included in the LC resonant circuit;
At least one sub power transmission driver provided corresponding to the at least one sub capacitor, wherein an active state / inactive state is selected by the enable signal;
A power transmission device comprising: The power transmission control device according to any one of claims 1 to 10 ,
A primary coil that is a component of the LC resonant circuit;
At least one sub-capacitor included in the LC resonant circuit;
At least one switch circuit provided in at least one of the at least one sub-capacitor and controlled to be turned on / off by the enable signal;
A power transmission device comprising: An electronic apparatus comprising a power transmission device according to claim 13 or claim 14, wherein.

Images