Power transmission device, power receiving device, power transmission system and control method

Abstract

A power transmission device, a power receiving device, a power transmission system, and a control method are disclosed. The power transmission device wirelessly transmits power to a power receiving device by using power supplied from a power supply device, including: a first authentication unit configured to perform device authentication to the power supply device; a second authentication unit configured to perform device authentication to the power receiving device; and a control unit that performs negotiation with the power receiving device regarding transmission power based on a device authentication result performed by the first authentication unit and a device authentication result performed by the second authentication unit.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 201880055074.1, application date August 20, 2018, and titled "Power transmission device, power receiving device, wireless power transmission system and control method thereof". Technical Field

[0002] The present invention relates to a wireless power transmission system. Background Art

[0003] In recent years, wireless power transmission technology is being widely developed. Japanese Patent Publication No. 2016-007116 discloses a power transmission device and a power receiving device, which comply with the specification (WPC specification) defined by the Wireless Power Consortium, a standard organization for contactless charging specifications. Japanese Patent Publication No. 2010-104097 also discloses a device authentication method for contactless charging between a power transmission device and a power receiving device. According to Japanese Patent Publication No. 2010-104097, the power transmission device sends the challenge data to the power receiving device via the power transmission coil, and the power receiving device sends the response data generated by the authentication calculation of the challenge data to the power transmission device via the power receiving coil. The power transmission device executes the device authentication protocol by verifying the response data received from the power receiving device.

[0004] In a power transmission device, an arrangement is known in which power is received from an external power source (e.g., an AC adapter) via a cable (e.g., a USB cable) for wireless transmission of power to a power receiving device. If these external power supply devices (such as an AC adapter and a cable) are not valid devices, excessive power may be supplied to the power transmission device and the power receiving device. Therefore, it is also desirable to perform device authentication on the AC adapter and the cable to confirm their validity and perform wireless power transmission with power corresponding to the validity authenticated by the device authentication.

[0005] Likewise, for example, in the case where higher power is to be transmitted due to an update of a specification such as the WPC specification, a new device authentication process may be adopted to authenticate the validity of the device. In this case, it is desirable to maintain compatibility with devices that support an earlier specification used before the adoption of the new device authentication. In addition, it is desirable to perform wireless power transmission by using higher power when wireless power transmission is to be performed between devices whose validity has been confirmed by device authentication, and it is desirable to perform wireless power transmission by using power supplied by an old version even when the device cannot be device authenticated by the old version. Summary of the invention

[0006] According to an embodiment of the present invention, a power transmission device, a power receiving device, a wireless power transmission system and a control method thereof are provided, which can advantageously use authentication results or results of determining whether device authentication is executable in a wireless power transmission operation in which device authentication for authenticating device validity can be performed.

[0007] According to one aspect of the present invention, there is provided a power transmission device which wirelessly transmits power to a power receiving device by using power supplied from a power supply device, the power transmission device comprising: a first authentication component for performing device authentication on the power supply device; a second authentication component for performing device authentication on the power receiving device; and a negotiation component for performing a negotiation with the power receiving device regarding the transmission power based on a result of the device authentication performed by the first authentication component and a result of the device authentication performed by the second authentication component.

[0008] According to another aspect of the present invention, there is provided a power receiving device which receives power wirelessly transmitted from a power transmitting device, the power receiving device comprising: an authentication component for performing device authentication on the power transmitting device; a notification component for notifying the power transmitting device that the power receiving device has a function for performing device authentication on the power transmitting device; a determination component for determining whether the power transmitting device supports device authentication based on a response of the power transmitting device to a notification from the notification device; an execution component for performing device authentication through the authentication component if the determination component determines that the power transmitting device supports device authentication; and a power receiving component for receiving power transmitted from the power transmitting device to supply power corresponding to one of a result of the determination by the determination device and a result of the device authentication by the execution device.

[0009] According to another aspect of the present invention, a wireless power transmission system is provided, which includes: a power supply device; a power transmission device, which is configured to wirelessly transmit power by using power supplied from the power supply device; a power receiving device, which is configured to receive power wirelessly transmitted from the power transmission device; a first authentication component, which is used to enable the power transmission device to perform device authentication to the power supply device; a second authentication component, which is used to enable the power transmission device to perform device authentication to the power receiving device; and a negotiation component, which is used to enable the power transmission device and the power receiving device to perform negotiation on the transmission power based on the result of the device authentication of the first authentication component and the result of the device authentication of the second authentication component.

[0010] According to another aspect of the present invention, a method for controlling a power transmission device is provided, which wirelessly transmits power to a power receiving device by using power supplied from a power supply device, the method comprising: performing device authentication on the power supply device; performing device authentication on the power receiving device; and performing negotiation with the power receiving device regarding the transmitted power based on a result obtained when performing device authentication on the power supply device and a result obtained when performing device authentication on the power receiving device.

[0011] According to another aspect of the present invention, a method for controlling a power receiving device that receives power wirelessly transmitted from a power transmitting device is provided, the method comprising: performing device authentication on the power transmitting device; notifying the power transmitting device that the power receiving device has a function of performing device authentication on the power transmitting device; determining whether the power transmitting device supports device authentication based on a response of the power transmitting device to a notification in the notification; and if it is determined in the determination that the power transmitting device supports device authentication, performing device authentication in the execution.

[0012] According to another aspect of the present invention, a method for controlling a wireless power transmission system is provided, the wireless power transmission system including a power supply device, a power transmission device and a power receiving device, the power transmission device being configured to wirelessly transmit power by using power supplied from the power supply device, the power receiving device being configured to receive power wirelessly transmitted from the power transmission device, the method including: causing the power transmission device to perform device authentication on the power supply device; causing the power transmission device to perform device authentication on the power receiving device; and causing the power transmission device and the power receiving device to perform negotiation on the transmission power based on a result obtained when causing the power transmission device to perform device authentication on the power supply device and a result obtained when causing the power transmission device to perform device authentication on the power receiving device.

[0013] Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a block diagram showing an example of the arrangement of a power transmission device according to the embodiment.

[0015] Figure 2 is a block diagram showing an example of the arrangement of a power receiving device according to the embodiment.

[0016] Figure 3 is a block diagram showing an example of the arrangement of a contactless charging system according to the embodiment.

[0017] Figure 4 This is an operation sequence diagram of a contactless charging system including USB certification and WPT certification.

[0018] Figure 5 : is a flowchart showing the GP setting process performed by the control unit of the power transmission device.

[0019] Figure 6 is a table showing the relationship between device authentication results and GP setting values.

[0020] Figure 7 1 is a flowchart showing state transition until power transmission is performed by the control unit of the power transmission device.

[0021] Fig. 8A This is a sequence diagram related to communication between a power transmission device and a power reception device.

[0022] Figure 8B This is a sequence diagram related to communication between a power transmission device and a power reception device.

[0023] Figure 8C This is a sequence diagram related to communication between a power transmission device and a power reception device.

[0024] Fig.8D This is a sequence diagram related to communication between a power transmission device and a power reception device.

[0025] Fig. 8E This is a sequence diagram related to communication between a power transmission device and a power reception device.

[0026] Fig. 9A is a flowchart showing state transition until power transmission is performed by the control unit of the power receiving device.

[0027] Fig. 9B is a flowchart showing state transition until power transmission is performed by the control unit of the power receiving device.

[0028] Fig. 9C is a flowchart showing state transition until power transmission is performed by the control unit of the power receiving device.

[0029] Fig. 10A is a view showing the arrangement of configuration groups.

[0030] Fig. 10B is a view showing the arrangement of power transmitter capability groups. DETAILED DESCRIPTION

[0031] Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiment to be described below, a device authentication will be described that confirms the validity of an AC adapter and a cable of a power supply device to be used as a power transmission device in addition to the validity of the power device. In addition, the following embodiment will describe a mechanism that can perform wireless power transmission while ensuring safety even if the AC adapter and the cable of the power supply device used as the power transmission device do not support device authentication. In addition, a control method will be described for performing device authentication on a power source, and for performing appropriate wireless power transmission between a power transmission device and a power receiving device via a power transmission coil and a power receiving coil by using multiple types of device authentication protocols for device authentication.

[0032] Figure 3 1 is a block diagram showing an example of the arrangement of a non-contact charging system as a wireless power transmission system according to an embodiment. Figure 3 In the present invention, a power transmission device (hereinafter referred to as TX 100) wirelessly transmits power supplied from an AC adapter 301 via a USB cable 300 to a power receiving device (hereinafter referred to as RX 200). RX 200 receives the power wirelessly transmitted from TX 100 and charges a battery, for example. The AC adapter 301 supplies power to TX 100 by converting power of a commercial power source supplied via a power plug 302 into a voltage suitable for TX 100.

[0033] Figure 1 It is shown that it can be applied to Figure 3 1 is a block diagram of an example of the arrangement of a power transmission device (TX 100) of a contactless charging system shown. TX 100 complies with the WPC specification and has the functions described in the WPC specification v1.2.2. It is assumed that TX 100 according to the present embodiment has the ability to supply power sufficient to output power up to a maximum of 15 W to a charging unit of a power receiving device (RX 200) that also complies with the WPC specification. Note that TX 100 and RX 200 will be described as devices that comply with the WPC specification. However, the present invention is not limited to this, and other contactless charging specifications may be used.

[0034] The control unit 101 controls the entire TX 100. An example of the control unit 101 is a central processing unit (CPU). The power supply 102 complies with the USB power delivery specification, and also complies with the USB authentication specification, by which device authentication between connected USB devices is performed. The power supply 102 receives operating power for the TX 100 from the AC adapter 301 via the USB cable 300, and supplies the power to operate at least the control unit 101 and the power transmission unit 103. The power transmission unit 103 generates an AC voltage and an AC current to be transmitted to the power receiving device (RX 200) via the power transmission coil 105. More specifically, the power transmission unit converts the DC voltage supplied by the power supply 102 into an AC voltage by a switching circuit having a half-bridge or full-bridge configuration using FETs. The power transmission unit 103 includes a gate driver that controls ON / OFF of the FET.

[0035] The communication unit 104 communicates with the RX 200 ( Figure 2 The communication unit 204 in the power transmission unit 103 performs wireless power transmission control communication. In the present embodiment, it is assumed that the communication performed by the communication unit 104 is a so-called inbound communication in which the communication is superimposed on the wireless power by modulating the AC voltage or current generated by the power transmission unit 103. However, the present invention is not limited to this, and the communication unit may perform outbound communication using a frequency different from that of the power transmission unit 103. For example, NFC, RFID, Wi-Fi (IEEE802.11 series), Bluetooth TM The display unit 106 displays and informs the user of the status of the TX 100 itself or the status of the non-contact charging system, which includes, for example, Figure 3 TX 100, RX 200, USB cable 300, AC adapter 301, etc. are shown. In the present embodiment, the display unit 106 is described as an LED. However, as long as the display unit can notify the user of the above-mentioned state, it may have another arrangement, and the display unit may be a speaker, a vibration generating circuit, or a display.

[0036] The memory 107 stores the overall status of the TX 100 and the non-contact charging system and the status of each component thereof ( Figure 3). The first authentication unit 108 performs device authentication on the power supply 102 and the USB cable 300 and AC adapter 301 connected to the power supply 102. In the present embodiment, the first authentication unit 108 is described as a unit that complies with the USB authentication specification. However, the first authentication unit may comply with another specification that supports device authentication, which may be Qualcomm's Quick Charge specification, or may comply with other specifications in addition to these specifications. The second authentication unit 109 performs device authentication between TX 100 and RX 200 by communicating via the communication unit 104. In the present embodiment, the device authentication performed by the second authentication unit 109 is referred to as wireless power transmission authentication (WPT authentication).

[0037] Despite Figure 1 The control unit 101, power supply 102, power transmission unit 103, communication unit 104, memory 107, first authentication unit 108, and second authentication unit 109 are described as separate components, but any number of these components can be combined in a single chip. For example, the power supply 102 that complies with the power delivery specification and the first authentication unit 108 that complies with the USB authentication specification can be combined in a single chip as a USB-related chip. In this case, the control unit 101 and the USB-related chip can be connected through, for example, general purpose input / output (GPIO) or serial communication.

[0038] Figure 2 : is a block diagram showing an example of the arrangement of the power receiving device (RX 200) according to the present embodiment. The RX 200 complies with the specification defined by the WPC, and has the functions described in the WPC specification v1.2.2.

[0039] In the RX 200, the control unit 201 controls the entire RX 200. An example of the control unit 201 is a CPU. The power receiving unit 203 converts the AC voltage and AC current received from the power transmission coil 105 via the power receiving coil 205 into a DC voltage and DC current for operating the control unit 201 and the charging unit 206. It is assumed that the power receiving unit 203 according to the present embodiment has the ability to output power up to a maximum of 15 W to the charging unit 206.

[0040] The communication unit 204 performs contactless charging control communication with the communication unit 104 of the TX 100 based on the WPC specification. This control communication is so-called inbound communication that performs load modulation on the electromagnetic wave received via the power receiving coil 205. However, the present invention is not limited to this, and the communication unit can perform outbound communication by using a frequency different from that of the power transmission unit 103. NFC, RFID, Wi-Fi (IEEE802.11 series), Bluetooth TM etc. for outbound communication.

[0041] The charging unit 206 charges the battery 207 by using the DC voltage and DC current supplied from the power receiving unit 203. The authentication unit 208 performs WPT authentication between the TX 100 (second authentication unit 109) and the RX 200 through communication via the communication unit 204. The memory 209 stores the RX 200 and the non-contact charging system ( Figure 3 ) and the status of each component thereof. Note that the state in which the TX 100 or RX 200 complies with the WPC specification (including WPT certification) is hereinafter represented as a state in which it complies with WPC specification version A. It is assumed here that WPC specification version A is a specification subsequent to WPC specification v1.2.2, and at least the WPT certification function has been added to the WPC specification version A.

[0042] The display unit 202 displays the power supply status, charging status, etc. In the present embodiment, the display unit 202 will be described as an LED. However, as long as the display unit can notify the user of the above status, it may have another arrangement, and the display unit may be, for example, a speaker, a vibration generating circuit, or a display. Note that although Figure 2 The power receiving unit 203, the authentication unit 208, the control unit 201, the memory 209, the communication unit 204, and the charging unit 206 are described as separate components in FIG. 2 , but any plurality of these components may be combined in a single chip.

[0043] In the contactless charging system including the above arrangement according to the present embodiment, the first authentication unit 108 of the TX 100 performs device authentication by using the AC adapter 301, the USB cable 300, and the first communication protocol (e.g., USB authentication via the USB cable). The second authentication unit 109 of the TX 100 performs device authentication to the RX 200 by using the second communication protocol that uses a medium different from the medium used for communication by the first communication protocol (e.g., the power transmission coil 105 and the power receiving coil 205).

[0044] The AC adapter 301, the USB cable 300 and the TX 100 (power supply 102) are based on Figure 3 The USB devices in the contactless charging system of the embodiment shown. The state that the USB devices support USB authentication and succeed in USB authentication indicates that these devices have no risk such as overheating when the power predetermined by USB authentication is applied. That is, when USB authentication succeeds, even if the predetermined power is supplied from the AC adapter 301 to the power supply 102 of the TX 100 via the USB cable 300, the power supply 102 of the TX 100, the USB cable 300, and the AC adapter 301 will not overheat.

[0045] If one of the power supply 102 of the TX 100, the USB cable 300, and the AC adapter 301 (forming a power supply path to the power transmission unit 103 of the TX 100) does not support USB authentication, the USB authentication will certainly not succeed. In this case, when a predetermined power is applied, there is a risk such as overheating for the device that does not support USB authentication. The state in which the device does not support USB authentication described here includes a state in which the device complies with one of multiple versions in the previous version of the USB specification, which were set before the current USB authentication specification was defined. In the present embodiment, it is assumed that a UBS device that complies with one of multiple versions in the previous version of the USB specification set before the USB authentication specification was defined will be referred to as a legacy USB device.

[0046] If the USB authentication fails in one of the power supply 102 of the TX 100, the USB cable 300, and the AC adapter 301, the above-mentioned risk will exist when the above-mentioned predetermined power is applied because this is also a case where the USB authentication fails. Here, the state of USB authentication failure includes a state where it is possible that one or both of the USB cable 300 and the AC adapter 301 are malicious USB devices that may appear to support USB authentication but actually do not support USB authentication.

[0047] The case where the RX 200 and the TX 100 comply with the WPC specification version A and succeed in the WPT certification means that even if the RX 200 and the TX 100 exchange the predetermined power, there is no risk such as overheating. On the other hand, when one or both of the RX 200 and the TX 100 do not comply with the WPC specification version A, the WPT certification is unsuccessful. In this case, if the above-mentioned predetermined power is supplied, each device that does not comply with the WPC specification version A is subject to risks such as overheating. Here, the state in which the device does not comply with the WPC specification version A includes a state in which the device complies with one of a plurality of previous versions of the WPC specification set before the WPC specification version A. In the present embodiment, it is assumed that a TX or RX that complies with one of a plurality of previous versions of the WPC specification set before the WPC specification version A will be referred to as a legacy TX or a legacy RX.

[0048] If WPT authentication fails for TX 100 and RX 200, there is a possibility that TX or RX may be a malicious TX or RX that appears to comply with WPT authentication but does not actually comply with WPT authentication (because if the device supports WPT authentication, authentication always succeeds). In this case, since WPT authentication fails, there is a risk such as overheating when the above-mentioned predetermined power is applied.

[0049] In the present embodiment, it is determined that when the USB authentication of the USB cable 300 and the AC adapter 301 is successful and the WPT authentication of the RX 200 and the TX100 is successful, the predetermined power can be safely supplied. That is, even if the power receiving unit 203 of the RX 200 supplies the predetermined power (15W) to the load (charging unit 206 in the present embodiment), there is no risk such as overheating. On the other hand, when the USB authentication of one of the TX 100 (power supply 102), the USB cable 300 and the AC adapter 301 is unsuccessful or when the WPT authentication of the RX 200 or the TX 100 is unsuccessful, there is a possibility that the predetermined power cannot be safely supplied. That is, if the power receiving unit 203 of the RX200 supplies the predetermined power of 15W to the load, there will be risks such as overheating. It is assumed below that when the authentication fails, the power supplied by the power receiving unit 203 is limited to a power (e.g., 5W or less) lower than the predetermined power (e.g., 15W) to avoid these risks.

[0050] However, in the related art, a control method that takes into account the multiple authentication methods in a system where multiple device authentication protocols such as USB authentication and WPT authentication exist as described above has not been proposed.

[0051] Figure 4 It is a sequence diagram including USB authentication and WPT authentication according to this embodiment. Figure 5 1 is a flowchart showing the operation of the control unit 101 of the power transmission device (TX 100) according to the present embodiment related to the guaranteed power (hereinafter referred to as GP) setting. GP represents a power value that is guaranteed for the output power to the load of the power receiving unit 203 even if the positional relationship of the TX 100 and the RX 200 is switched and the power transmission efficiency between the power transmission coil 105 and the power receiving coil 205 is reduced. The load of the power receiving unit 203 is the power supply object of the power receiving unit 203, and includes at least the charging unit 206. For example, if the GP is 5W, the TX 100 controls the power transmission unit 103 so that the power receiving unit 203 can output 5W of power even if the power transmission efficiency between the coils is reduced by switching the positional relationship between the power transmission coil and the power receiving coil. Figure 4 and Figure 5The operation shown in (GP determination operation) will be described later in Figure 6 is described in the explanation.

[0052] Figure 6 : is a table showing an example of each GP limit value used in negotiation (to be described later) according to the results of USB authentication and WPT authentication.

[0053] "USB authentication not supported" of column 600 indicates a state in which at least one of the power supply 102, USB cable 300, and AC adapter 301 of TX 100 does not support USB authentication (but authentication has succeeded in each device supporting USB authentication). "USB authentication failed" of column 601 indicates a state in which USB authentication of one of the power supply 102, USB cable 300, and AC adapter 301 of TX 100 has failed although the device supports USB authentication. "USB authentication success" of column 602 indicates a state in which USB authentication has succeeded for each of the power supply 102, USB cable 300, and AC adapter 301 of TX 100. Row 603 indicates a state in which RX 200 does not support WPT authentication, row 604 indicates a state in which WPT authentication of RX 200 has failed although WPT authentication is supported, and row 605 indicates a state in which WPT authentication has succeeded in RX 200 supporting WPT. Note that when three types of GP voltage values ​​"0, 2.5, 5" are written in the fields of the table, it is predetermined to adopt one of these values.

[0054] according to Figure 6 , in the case of the USB certification unsupported state (column 600), by limiting the GP to 5W, power transmission that avoids risks such as overheating can be performed regardless of the result of the WPT certification. In the case of the WPT certification failure state (row 604) of column 600, the GP can be limited to a value less than that in the case of the WPT certification unsupported state (row 603), such as 0W (no power transmission) or 2.5W (lower than 5W). This is because the WPT certification failure indicates that the RX may be a malicious RX that supports WPT certification but cannot accurately support WPT certification (for example, a counterfeit device that does not meet the WPC specification). Although it is sufficient to limit the GP to 5W from the point of view of the above-mentioned risks such as overheating, limiting the GP to a GP (0W or 2.5W) lower than the GP of a conventional RX that does not support WPT certification but accurately complies with the specification has the advantage of eliminating counterfeit devices.

[0055] In the same manner, in the case of the USB authentication failure state (column 601), the GP may be limited to a value less than that in the case of the USB authentication non-support state (column 600), such as 0W (no power transmission) or 2.5W (less than 5W). This is because the USB authentication failure indicates that the USB device may be a malicious USB device that supports USB authentication but cannot accurately support USB authentication. Therefore, limiting the GP to 0W or 2.5W, which is lower than the GP of a conventional USB that does not support USB authentication but accurately complies with the specification, has the advantage of eliminating counterfeit devices.

[0056] In addition, the case of the USB authentication success state (column 602) indicates that even if the RX 200 supplies 15 W of power to the load, Figure 3 The power supply 102 of TX 100, USB cable 300 and AC adapter 301 related to USB in the system do not have the above-mentioned risks. Therefore, TX 100 sets GP based on the result of WPT authentication. In the case of WPT authentication unsupported state (row 603), GP is set to 5W based on the above reasons, and in the case of WPT authentication failed state (row 604), GP is limited to a lower GP value (0W or 2.5W). In the case where USB authentication is successful (column 602) and WPT authentication is also successful (row 605), it is determined that there is no above-mentioned risk, and TX 100 sets 15W (i.e., the maximum value of the capability of each of TX 100 and RX 200) as the GP limit value. In this way, when all of the device authentication operations of USB authentication and WPT authentication are successful, the power transmission of the maximum capability of TX 100 and RX 200 is determined in the negotiation performed in the negotiation stage (to be described later).

[0057] <Sequence from activation to power transmission in the contactless charging system>

[0058] Will be used by Figure 4 and Figure 5 Described in Figure 3 The sequence from activation to power transmission in the contactless charging system shown in . If there is at least one device that does not support the authentication operation or fails the authentication among the authentication target devices, the TX 100 operates with USB authentication and WPT authentication to limit the transmission power.

[0059] When the USB cable 300 and the AC adapter 301 are connected to the power supply 102 of the TX 100 (400), the control unit 101 of the TX 100 performs USB authentication (401, step S501). In the USB authentication, the control unit 101 causes the first authentication unit 108 to operate and determines whether all the authentication object USB devices (in this embodiment, both the USB cable 300 and the AC adapter 301) support USB authentication. When all of the USB authentication operations performed are successful, the first authentication unit 108 performs USB authentication on all of the USB devices and determines that "USB authentication is successful". In addition, in this embodiment, for the case where all of the USB devices fail to perform USB authentication, "USB authentication is not supported" and "USB authentication failed" have been set as authentication results. If even one device supports USB authentication but fails to pass the authentication, it is determined as "USB authentication failed". When all of the devices that have not successfully passed the authentication are devices that do not support USB authentication, it is determined as "USB authentication is not supported".

[0060] For example, in the case where the USB authentication of the AC adapter 301 succeeds but the USB cable 300 does not support USB authentication, it is determined as "USB authentication is not supported". Also, for example, in the case where the USB authentication of the AC adapter 301 succeeds but the USB authentication of the USB cable 300 fails although the USB authentication is supported in the USB cable, it is determined as "USB authentication failed". Additionally, for example, if If the USB authentication of both the AC adapter 301 and the USB cable 300 succeeds, it is determined that “USB authentication succeeds.” The control unit 101 holds these USB authentication results in the memory 107 (step S502 ).

[0061] Next, the control unit 101 determines the power specifications of the voltage and current supplied from the AC adapter 301 with respect to the AC adapter 301 based on the sequence of the USB PD (USB Power Delivery Specification) (402). Since the power supply voltage is determined by the internal arrangement of the TX 100, the current value is determined in this case. Assuming that Figure 3 In the system, the voltage of the power supply 102 is 15V, and the maximum output current of the power supply 102 is 3A. Here, in order to reduce the current value, the control unit 101 of the TX 100 performs the following Figure 6 For example, in the case of "USB authentication is not supported", based on Figure 6 Column 600 of , 5W is determined as the maximum GP value through negotiation in the negotiation phase (described later) of the WPC specification.

[0062] The control unit 101 determines the current value in consideration of the loss inside the TX 100. For example, it is assumed that the positions of the power transmission coil and the power receiving coil have been changed, and when 5W (i.e., the GP when the efficiency between the coils is the lowest) is output to the RX 200, the system efficiency is 50%. In this case, the power supplied by the power supply 102 to the power transmission unit 103 and the control unit 101 is 10W (5W×2). Since the power supply voltage is 15V, the output current is 0.67A. In this embodiment, in the case where one of the USB devices does not support USB authentication, it is sufficient to limit the GP to 5W to avoid risks. Therefore, it is sufficient that the current value to be determined by the power supply 102 through negotiation with the AC adapter 301 based on the sequence of USB PD is approximately 0.67A. Based on the current value to be determined, the control unit 101 of the TX 100 determines the power specification with the AC adapter 301. On the other hand, in the case where the USB authentication is successful, the power specification is determined to be 2.0A (15W×2 / 15V), so that the GP value of 15W can be supported.

[0063] The control unit 101 of the TX 100 activates the power transmission unit 103 (403). The activation of the power transmission unit 103 may be performed by a so-called power-only setting in which power is input from the power supply 102 to at least one of the control unit 101, the power transmission unit 103, and the communication unit 104. Alternatively, the first authentication unit 108 may reset at least one of the control unit 101, the power transmission unit 103, and the communication unit 104 by inputting a reset signal (LO: approximately 0V) (not shown) to at least one of the control unit 101, the power transmission unit 103, and the communication unit 104 of the TX 100. In this case, after the power specification is determined and the GP value has been determined, the first authentication unit 108 cancels the reset by changing the reset signal to HI (e.g., 3.3V).

[0064] When the power transmission unit 103 is activated, the TX 100 starts the operation in accordance with the WPC specification. In the present embodiment, in addition to each stage in accordance with the WPC specification, the authentication stage is defined as a stage for performing WPT authentication. In the authentication stage, TX and RX perform device authentication operations based on WPT authentication. If both TX and RX support the authentication stage, TX and RX perform state transitions in the order of selection stage, packet Internet search (ping) stage, identification and configuration stage (I&C stage), authentication stage, negotiation stage, calibration stage, and power transmission stage (PT stage).

[0065] More specifically, first in the selection phase, the power transmission unit 103 transmits an analog ping (405) via the power transmission coil 105. The analog ping is an extremely low power signal for detecting an object present near the power transmission coil 105. The TX100 detects a voltage value or a current value of the power transmission coil when the analog ping is transmitted, and if the voltage is lower than a predetermined threshold or the current value exceeds a predetermined threshold, it is determined that an object exists, and then the process is converted to the ping phase.

[0066] In the ping phase, TX 100 sends a digital ping at a higher power than the analog ping. The digital ping has enough power to activate the control unit 201 of RX 200 present near the power transmission coil 105. After being activated by the digital ping received via the power receiving coil 205, the control unit 201 of RX 200 notifies TX 100 of the magnitude of the received voltage (407) and transitions to the I&C phase. After receiving the notification of the received voltage value, TX 100 transitions to the I&C phase. Next, RX 200 sends an ID packet and a configuration packet to TX 100 (408, 409).

[0067] Next, the second authentication unit 109 performs WPT authentication processing in the authentication phase (410, S503). The authentication object is the RX200 as a power receiving device in the wireless power transmission system. The control unit 101 stores the WPT authentication result in the memory 107 (step S504). The control unit 101 Figure 6 The USB authentication result stored in the memory 107 in step S502 and the WPT authentication stored in the memory 107 in step S504 determine (404, step S505) the maximum value of the GP to be used in the negotiation phase. Fig. 8E Describes the details of the authentication phase.

[0068] Subsequently, the control unit 101 of the TX 100 determines the GP (411) by negotiating with the RX 200 in the negotiation phase. The negotiation is performed here so that the transmission power is equal to or less than the GP value (404), that is, the allowed transmission power, which has been limited by the first authentication unit 108 (USB authentication) and the second authentication unit 109 (WPT authentication) based on the device authentication result. For example, if the USB authentication result is "USB authentication success" and the WPT authentication result is "WPT authentication success", then Figure 6As shown, it is allowed to set the GP up to 15W. On the other hand, if the USB authentication result is "USB authentication not supported", the GP is limited to 5W or less. In this case, if a GP exceeding 5W is requested from the control unit 201 of the RX 200 during the negotiation phase, the control unit 101 of the TX 100 sends a NAK to the request. Otherwise, if a GP equal to or less than the limit value is requested, the control unit 101 sends an acknowledgment (ACK).

[0069] As described above, since the control unit 101 of the TX 100 sets the GP based on the results from both the USB authentication and the WPT authentication, risks such as overheating can be avoided by limiting the magnitude of the GP when one of the multiple authentication operations fails. Only when all of the authentication operations are successful, the GP can be set to the maximum value of the capacity of the power transmission unit 103.

[0070] Next, the control unit 101 of the TX 100 sends (412) a cause notification to notify the control unit 201 of the RX 200 of the cause of the restriction on the GP. The device authentication results from the first authentication unit 108 and the second authentication unit 109 are sent to the RX 200 as the power receiving device through the cause notification. The cause notification may be a result (RESULT) packet ( Fig. 8E 820), which will be described later. In the present embodiment, the control unit 101 of the TX 100 stores the WPT authentication result and the USB authentication result related to the power supply 102 of the TX 100 in a result packet, and transmits the result packet to the control unit 201 of the RX 200. For example, the control unit 101 sets 1 bit in the result packet for storing the WPT authentication result, stores "1" if the WPT authentication is successful, or stores "0" if the WPT authentication is unsuccessful. The control unit 101 sets 1 bit in the result packet for storing the USB authentication results of the AC adapter 301 and the USB cable 300, stores "1" if all USB authentication operations are successful, and stores "0" otherwise. In this way, the control unit 101 transmits the result packet storing the device authentication result.

[0071] Subsequently, the control unit 101 of TX 100 and the control unit 201 of RX 200 perform the process of the calibration phase (413) and transition to the PT phase. In the PT phase, RX 200 supplies power to the load (414). The control unit 201 of RX 200 can display (416) a message (412) that power is limited on the display unit 202 based on the cause notification. In the same manner, the control unit 101 of TX 100 can display (415) a message that power is limited on the display unit 106 based on the device authentication result (cause notification). For example, it can display a message "Slow-speed charging is performed because USB authentication (because of USB device) is unsuccessful" based on the USB authentication result and WPT authentication result of the result grouping. Through this display, the user can know that charging will take longer than when power is not limited, and can take measures such as replacing the USB cable or USB adapter with a USB authentication support product. The display can also refer to the WPT authentication result, and it is obvious that the same effect can be achieved. In addition, in the absence of power limitation, the display can be performed by displaying different colors or light patterns of LEDs. The same effect can be achieved by notifying the user using a sound or vibration different from that used in the absence of power limitation.

[0072] In the present embodiment, after determining whether to limit the transmission power by USB authentication, the WPC power transmission device is activated. However, after activating the USB device and the WPC device at the same time, asynchronously performing the USB authentication and the WPC authentication, and starting the power transmission between the WPC devices, in the case where the transmission power limitation by the USB authentication has been determined, the same effect can be achieved by renegotiating the power transmission limitation of the WPC. However, according to the present embodiment, by activating the WPC power transmission device after determining whether to limit the transmission power in the USB authentication, an additional effect can be expected. When the TX 100 is to determine the GP in the negotiation phase (411), since it has been determined whether to limit the transmission power in the USB authentication, there is no need to generate a renegotiation process.

[0073] <Backward compatibility with WPT certified operations>

[0074] As the power transmitted by the WPC specification is larger, in order to avoid risks, it is necessary to add the WPT certification function to the old version of the WPC specification. In this case, the TX with the WPT certification function must ensure backward compatibility not only with the RX that also has the WPT certification function, but also with the conventional RX. Similarly, the RX with the WPT certification function must ensure backward compatibility with the conventional TX. However, a technology for adding a WPT certification function that complies with the conventional WPC specification while also considering backward compatibility has not yet been proposed.

[0075] Therefore, in the case where new device certification is added to the standard specification of wireless power transmission, a mode of maintaining compatibility with the standard specification of a version not conforming to the new device certification will be described below.

[0076] Figure 7 : is a flowchart showing the operation of the control unit 101 of the TX 100 according to this embodiment. FIG. 8A to FIG. 8B 1 is a sequence diagram for explaining the backward compatibility of TX 100 or RX 200 in version A. Although WPT authentication according to the present embodiment will be described as a challenge response device authentication using a digital certificate in the same manner as USB authentication, WPT authentication is not limited thereto. TX 100 serves as an initiator that sends a challenge text to RX 200, and RX 200 serves as a responder that encrypts the challenge text and sends the encrypted challenge text to TX 100. 9A to 9C is a flowchart showing the operation of the control unit 201 of the RX 200 . Fig. 10A is a view showing an example of the bit arrangement of a configuration packet conforming to the WPC specification. Fig. 10B 1 is a view showing an example of a bit arrangement of a power transmitter p compatibility group compliant with the WPC specification. Note that the same reference numerals denote the same components throughout all the drawings.

[0077] Before explaining the sequence diagram and the flow chart, the TX and RX categories based on the WPC specification v1.2.2 will be described. TX and RX each having a GP of 5W are classified under the basic power profile (BPP). TX and RX each having a GP higher than 5W but not more than 15W are classified under the extended power profile (EPP). In addition, in the WPC specification v1.2.2, a function of performing GP-related negotiation between TX and RX has been added. Both TX and RX classified under EPP have a negotiation function. TX and RX classified under BPP are further classified into devices that support the negotiation function and devices that do not support the negotiation function. TX can be configured by grouping ( Fig. 10A ) determines whether RX has the negotiation function by using the Neg bit (block 4, bit 7) in the configuration packet, in which the setting information of RX is described. If the Neg bit is "1", RX has the negotiation function. If the Neg bit is "0", RX does not have the negotiation function. In this embodiment, unless otherwise specified, it is assumed that the legacy TX and the legacy RX each have the negotiation function, and the negotiation is performed in the negotiation stage.

[0078] TX and RX compliant with WPC specification version A for WPT certification must be backward compatible with legacy RX and legacy TX compliant with WPC specification v1.2.2. That is, TX compliant with WPC specification version A needs to operate without conflict with RX compliant with WPC specification earlier than version A. In the same way, RX compliant with WPC specification version A needs to operate without conflict with TX compliant with WPC specification earlier than version A.

[0079] Therefore, reference will be made to Figure 7 , FIG. 8A to FIG. 8B as well as 9A to 9C The backward compatibility of the TX 100 and RX 200 compliant with version A shown in this embodiment with the WPC specification v1.2.2 is described. The TX and RX of the traditional EPP compliant with the WPC specification v1.2.2 perform state transitions in the order of the selection phase, the ping phase, the I&C phase, the negotiation phase, the calibration phase, and the PT phase. In the case where at least one of the traditional TX and the traditional RX is a BPP device without a negotiation function, the TX and the RX perform state transitions in the order of the selection phase, the ping phase, the I&C phase, and the PT phase.

[0080] As described above, if both TX and RX meet the authentication phase, TX and RX are converted in the order of selection phase, ping phase, I&C phase, authentication phase, negotiation phase, calibration phase, and PT phase. Here, the authentication phase is to be performed before the negotiation phase. The reason is as follows. Figure 6 It is described how the value of GP changes according to the WPT authentication result. Consider a case where, after the GP has been determined through negotiation between TX and RX in the negotiation phase, a transition to the authentication phase is performed. In this case, in order to avoid the above-mentioned risks due to the result of the authentication phase, it is possible that the already determined GP can be changed again. This re-change of the GP is problematic because it complicates the order of transition to the PT phase, thereby taking more time. By performing the authentication phase before the negotiation phase, the GP can be restricted in the authentication phase, and the GP can be determined in the negotiation phase on the premise of the restricted GP. In this way, by limiting the GP in the authentication phase before the negotiation phase, a re-change of the GP does not occur in the transition to the PT phase, and the transition to the PT phase can be performed quickly.

[0081] <TX 100 and RX 200 are conventional TX and conventional RX respectively>

[0082] First, a description will be given of a sequence diagram of WPC specification v1.2.2 in the case where both TX 100 and RX 200 are devices compliant with conventional EPP. Fig. 8ANote that in the following explanation, it is assumed that the USB authentication operation of the TX 100 for the USB cable 300 and the AC adapter 301 has succeeded. Figure 7 and Fig. 9A Only the parts related to the traditional EPP are used in the flowchart of Figure 7 The processing of steps S703 to S708 in is not presented in the conventional TX, and Fig. 9A The processing of steps S903 to S905 and S908 in is not present in the conventional PX. Fig. 8A Only the sequence of the I&C phase and the sequence of subsequent phases related to backward compatibility are shown.

[0083] After the processing of the selection phase and the ping phase has been performed between TX 100 and RX 200, the state transitions to the I&C phase (step S701). In the I&C phase, RX 200 sends an identification packet (ID packet) to TX 100 (800, step S901). In addition to its own personal identification information, the ID packet also stores information elements that identify the supported WPC specification version (v1.2.2 in this case). Next, RX 200 sends a configuration packet to TX 100 (801, step S901). The configuration packet of the WPC specification v1.2.2 includes a maximum power value and a Neg bit, the maximum power value is a specific value of the maximum power that RX 200 can supply to the load, and the Neg bit is a bit indicating whether there is a negotiation function. Here, RX 200 sets "1" in the Neg bit and indicates that it has a negotiation function.

[0084] Upon receiving the ID packet and the configuration packet from the RX 200 (step S702), the TX 100 determines whether the RX 200 has the negotiation function (step S704). Since the RX 200 has the negotiation function ("Yes" in step S704), the TX 100 sends an ACK to the configuration packet (steps S713, 802) and transitions to the negotiation phase (step S709). Note that in the case where the RX 200 is a BPP that does not support the negotiation function (Neg bit is 0), the TX 100 will transition to the PT phase (step S712) without sending an ACK. Similarly, in the case where the TX 100 itself is a BPP and does not support the negotiation function, the TX 100 will transition to the PT phase without sending an ACK. In this case, the GP is limited to 5W.

[0085] The reception of ACK ("Yes" in step S902) allows RX 200 to know that TX 100 supports the negotiation function, and RX transitions to the negotiation phase (step S906). RX 200 then transmits a specific request packet to request the power required by its own device (e.g., 15 W). In this case, RX 200 transmits a specific request (15 W) indicating a request for 15 W for GP as an information element of the specific request packet to TX 100 (803). Here, after transmitting the configuration packet, if RX 200 does not receive ACK within 15 milliseconds ("No" in step S902), RX 200 of WPC specification v1.2.2 will determine (step S909) that TX 100 is a BPP without the negotiation function. Subsequently, RX 200 transitions to the PT phase (step S910).

[0086] Upon receiving the specific request (15W), TX 100 compares its own transmission power with 15W. If power transmission is possible, TX sends an ACK indicating a positive confirmation to RX 200. Otherwise, TX sends a NAK indicating a rejection of the request to RX. Here, TX determines (step S710) the GP of 15W by determining that 15W of power can be transmitted, and sends (804) ACK. TX 100 transitions to the calibration phase. Upon receiving an ACK for the specific request (803) from TX 100, RX 200 transitions to the calibration phase (step S907). In the calibration phase, TX 100 performs adjustment based on the correlation between the transmission power value from TX 100 to RX 200 measured in TX 100 and the reception power value measured in RX 200. After the calibration phase is completed, TX 100 and RX 200 transition to the PT phase and start wireless power transmission (steps S712 and S910).

[0087] As described above, the TX 100 of the WPC specification v1.2.2 determines whether the RX 200 is an EPP and BPP with negotiation function or a BPP without negotiation function based on the Neg bit. In the former case, the TX transitions to the negotiation phase. In the latter case, the TX transitions to the PT phase.

[0088] In addition, by making a determination based on whether ACK is received as a response within 15 milliseconds from the transmission of the configuration packet, if ACK is received, the RX 200 of the WPC specification v1.2.2 transitions to the negotiation phase. Otherwise, the RX transitions to the PT phase.

[0089] Through the above operations, in the WPC specification v1.2.2, compatibility between the TX 100 and RX 200 having the negotiation function and the TX 100 and RX 200 not having the negotiation function is ensured.

[0090] <When TX 100 is version A and RX 200 is conventional RX>

[0091] Reference Figure 8B , Figure 6 , Figure 7 and Fig. 9A , a case where the TX 100 complies with the version A and the RX 200 is a conventional RX will be described. Note that in the following explanation, it is assumed that the USB authentication operation of the USB cable 300 and the AC adapter 301 by the TX 100 has succeeded. Since the entire description below is a description related to the backward compatibility of the WPC specification, it is obvious that the description is applicable even in an arrangement where the TX 100 does not include the first authentication unit.

[0092] First, we will define the Auth bit in the configuration group. Fig. 10A The arrangement of the configuration group according to the WPC specification v1.2.2 is shown. Note that the explanation of the parts not related to the present invention will be omitted. The configuration group includes multiple reserved areas, for example, a reserved area 1001 from bit 4 to bit 6 in block 2, a reserved area 1000 from bit 0 to bit 7 in block 1, and a reserved area 1002 from bit 2 to bit 0 in block 4. In the present embodiment, the Auth bit is arranged in bit 6 of block 2. However, the arrangement of the Auth bit is not limited to this and may be arranged in other reserved areas. Note that each bit of the reserved area in the WPC specification v1.2.2 is 0. If the RX 200 itself supports WPT authentication, the RX stores "1" in the Auth bit. Otherwise, "0" is stored in the Auth bit.

[0093] TX 100 determines whether RX 200 supports WPT authentication by configuring the Auth bit in the packet (step S703). Since RX 200 is a conventional RX, the Auth bit is "0". TX 100 determines that RX 200 does not support WPT authentication ("No" in step S703), and transitions to the negotiation phase. Here, if TX receives a request for GP of 15W from RX 200, TX sends a NAK indicating rejection of the request to RX 200 (805). Figure 6 As described in , this is because the RX 200 does not support WPT certification, and therefore the TX 100 determines that the power of 15 W should not be transmitted to avoid risks.

[0094] When its request is rejected by NAK, RX 200 sends a general request defined by the WPC specification v1.2.2 to know the GP value that can be set by TX 100. Here in this embodiment, in the general request, the message requesting the transmitter capability packet will be represented as a general request (capability). The transmitter capability packet includes the GP value that can be set and is a packet defined by the WPC specification v1.2.2.

[0095] Once the general request (capability) is received (806), TX 100 is based on the above Figure 6 to determine the GP of 5W corresponding to the state where WPT authentication is not supported (row 603) and the state where USB authentication is successful (column 602). TX 100 stores the information indicating 5W in the guaranteed power value of the power transmitter capability packet and sends the packet to RX 200 (807).

[0096] As described above, by using the Auth bit defined in this embodiment, TX 100 compliant with the WPC specification version A can operate conflict - free with respect to a legacy RX compliant with a WPC specification earlier than version A.

[0097] <The case where both TX 100 and RX 200 are compliant with version A>

[0098] Next, reference will be made to Figure 6 、 Figure 7 、 Fig. 8E and Fig. 9A to describe the case where both TX 100 and RX 200 are compliant with the WPT authentication process. Note that in the following explanation, it is assumed that the USB authentication operation of the USB cable 300 and the AC adapter 301 by TX 100 has been successful. Before the explanation, the operations of TX 100 and RX 200 compliant with version A of the WPT authentication will be described.

[0099] The RX 200 of version A sends a configuration packet to TX 100, in which "1" is stored in the Auth bit. Based on the Auth bit of the configuration packet, the TX 100 of version A determines that RX 200 supports WPT authentication ("yes" in step S703), and sends an ACK(auth) to RX 200 (step S705, 802). ACK(auth) is a confirmation that can be distinguished from ACK, which is configured by a bit pattern different from ACK and is a packet indicating the confirmation of the configuration packet and that TX 100 supports WPT authentication.

[0100] Upon determining that RX 200 supports WPT authentication in this manner, TX 100 sends ACK(auth) and transitions to the authentication phase (step S706). On the other hand, upon receiving ACK(auth) ("Yes" in step S903), RX 200 determines that TX 100 supports WPT authentication (step S904), and transitions to the authentication phase (S905).

[0101] Fig. 8E Processes 814 to 820 in FIG. 8 show an example of WPT authentication according to the present embodiment. First, TX 100 sends a Get Digest (GET_DIGEST) message to RX 200 (814, S707). The Get Digest packet is a packet requesting information related to a digital certificate held by RX 200. RX 200 sends a Digest (DIGEST) (815) in response to the Get Digest packet. The Digest is information related to a digital certificate owned by RX 200. Next, TX 100 sends a Get Certificate (GET_CERTIFICATE) packet requesting detailed information related to the digital certificate to RX 200 (816). RX 200 sends a Certificate (CERTIFICATE) (817) in response to the Get Certificate packet.

[0102] Next, TX 100 sends a CHALLENGE message including a challenge text to RX (818), and RX 200 sends a RESPONSE in which the challenge text has been encrypted to TX 100 (819). After confirming the validity of the response, TX 100 sends a RESULT (success) to RX (820, step S708), and transitions to the negotiation phase (step S709). The RESULT (success) packet indicates a RESPONSE result that the WPT authentication has been successful. Upon receiving the RESULT (success), RX 200 transitions to the negotiation phase (step S906).

[0103] During the negotiation phase, TX 100 Figure 6 The negotiation operation is performed by determining the GP of 15W corresponding to the state of WPT authentication success (row 605) and the state of USB authentication success (column 602). Upon receiving the request for the GP of 15W from the RX 200 (803), the TX 100 itself refers to Figure 6 To set the GP value of 15W for negotiation. Therefore, TX sends ACK confirming the request to RX 200 (804). If the authentication fails as a result of the response, TX 100 sends a result (failure) indicating the failure (RESULT (fail)) to RX 200 instead of the result (success). TX then sends an ACK to RX 200 based on the result (success). Figure 6The GP value is determined in a subsequent negotiation phase. Alternatively, the TX 100 may stop the power transmission unit 103 after sending the result (failure).

[0104] As described above, the TX 100 according to the present embodiment can not only operate with respect to the RX compliant with the WPC specification of an earlier version than Revision A, but can also operate with respect to the RX compliant with Revision A without conflict.

[0105] A supplementary explanation will be given here about the time interval between packets from obtaining the digest (814) to the result (success) (820). For example, in the negotiation phase of the WPC specification v1.2.2, the response of the packet from TX 100 to RX 200 is required to be within 10 milliseconds from the trailing edge of the packet from RX 200 to the leading edge of the response packet from TX 100. However, the initiator (TX 100) in the authentication phase requires encryption / decryption processing to confirm the validity of each packet (digest, certificate, and response) related to the digital certificate and sent by RX 200. Therefore, it takes time to respond in the authentication phase. Therefore, in the authentication phase, a longer response time is set compared to the response time of other phases. In the present embodiment, the response time is set to 50 milliseconds. That is, in Fig. 8E In the example, the response time is the time from digest to obtaining certificate, the time from certificate to challenge, and the time from response to result (success). Prolonging the response time has the effect of reducing the need for the control unit 101 of the TX 100 to operate at high speed and achieving cost reduction by reducing the power consumption of the control unit 101 and using a lower speed CPU.

[0106] Note that although TX 100 determines whether the power receiving device supports WPT authentication by configuring the Auth bit of the packet, this can be determined by the version information in the ID packet. If TX determines that the power receiving device supports WPT authentication when the version information indicates version A (or any subsequent version), or if TX determines that the power receiving device does not support WPT authentication when the version information indicates a version earlier than version A, the same effect can be achieved.

[0107] <Case 1: TX is conventional TX and RX is version A>

[0108] Reference Figure 8C , Figure 6 and Fig. 9A , a case where the TX 100 is a conventional TX and the RX 200 complies with version A will be described. Note that in the following explanation, it is assumed that the USB authentication operation of the TX 100 for the USB cable 300 and the AC adapter 301 has succeeded. First, the operation of the RX 200 compliant with version A will be described.

[0109] RX 200 notifies TX 100 by sending a configuration packet supporting WPT authentication (800, 801). However, since TX 100 is a legacy TX, it will ignore the Auth bit. Since RX 200 complies with the negotiation function, TX 100 sends ACK and transitions to the negotiation phase (step S704, step S713, and step S709 are "yes").

[0110] Upon receiving ACK (802, "Yes" in step S902), RX 200 determines that TX 100 does not support WPT authentication and is a legacy TX (step S908). This is because, since RX itself supports WPT authentication, if TX 100 also supports WPT authentication, ACK (auth) should have been received. Note that if RX 200 does not receive ACK within 15 milliseconds from the transmission of the configuration packet ("No" in step S902) and does not receive ACK (auth) either ("No" in step S903), the process proceeds to step S909. In this case, RX 200 determines that TX 100 is BPP and does not support the negotiation function (step S909), and transitions to the PT phase (step S910).

[0111] The RX 200 performs GP negotiation in the negotiation phase, but the RX 200 determines that it should not receive 15 W of power to avoid Figure 6 The above-described risks. RX 200 determines the GP of 5W corresponding to the WPT authentication unsupported state (row 603) and the USB authentication successful state (column 602) as the GP for negotiation, and sends a specific request (5W) (809). RX 200 receives ACK (810) from TX 100, and ends the negotiation phase. After performing a predetermined process, RX 200 transitions (step S907) to the calibration phase and transitions (step S910) to the PT phase.

[0112] As described above, the RX 200 compliant with WPC specification version A can operate without conflict with the TX 100 compliant with a WPC specification of a version earlier than version A. Fig. 8E As mentioned above, even when the TX 100 supports WPT certification, the RX 200 can operate without conflict.

[0113] <Case 2: TX is conventional TX and RX is version A>

[0114] In the above description, in the case where the RX 200 complies with version A, it is determined whether the TX 100 supports WPT authentication and whether the TX complies with the negotiation function based on the response to the configuration packet from the TX 100. More specifically, an example has been described in which the above determination is made based on whether ACK or ACK(auth) is received within 15 milliseconds from the transmission of the configuration or based on whether ACK or ACK(auth) has not been received. Reference will be made here to Fig.8D and Fig. 9C Another example of determining whether the TX 100 complies with version A is described. Note that in the following explanation, it is assumed that the USB authentication operation by the TX 100 on the USB cable 300 and the AC adapter 301 has succeeded.

[0115] Once the ACK in response to the configuration packet is received, the RX 200 sends an authentication request (Auth Req) to request the execution of WPT authentication (step S912, 810). The authentication request is an authentication request packet for requesting the TX 100 to switch to the authentication phase, and is a reserved packet whose packet type is not defined in the WPC specification v1.2.2. In this embodiment, the packet header in the reserved packet defines the 0x40 packet as an authentication request packet. After returning the ACK to the configuration packet, in response to the reception of the authentication request packet, the TX conforming to version A switches to the authentication phase and starts the WPT authentication.

[0116] On the other hand, a TX that does not conform to version A operates as follows. In the WPC specification v1.2.2, it is specified that when the TX 100 sees a packet type in the negotiation phase and determines that an unsupported packet is received, the TX will send an undefined response (ND Resp) packet. However, it is specified that the TX 100 will not send a response even if an unsupported packet is received in the I&C phase. Since the TX 100 has already sent an ACK (802) to the configuration packet, it is set to the negotiation phase. Therefore, the TX 100, which is a conventional TX, sends an undefined response to the RX 200 (811) in response to the authentication request packet. Upon receiving the undefined response ("Yes" in step S913), the RX 200 determines that the TX 100 does not support WPT authentication (S908), and transitions to the negotiation phase without performing WPT authentication (step S906).

[0117] Here, if RX 200 does not receive an undefined response in response to the authentication request ("No" in step S913) but receives ACK ("Yes" in step S914), the process proceeds to step S904. In this case, RX 200 determines that TX100 supports WPT authentication (step S904), and RX transitions to the authentication phase (step S905). Note that if RX 200 does not receive an undefined response or ACK in response to the authentication request ("No" in step S914), RX 200 sends a power transmission stop request to TX 100 and returns to the selection phase (step S915). The power transmission stop request is performed by sending, for example, a transmission end packet (ETP). By sending a power transmission stop request to TX 100, when the WPC sequence cannot be continued due to a failure of TX 100 or a decrease in the communication quality between TX100 and RX 200, an effect of returning the system to the initial state can be achieved.

[0118] In addition, in the case where RX 200 does not receive an undefined response or ACK, RX 200 can resend the authentication request. This is because TX 100 may have failed to correctly receive the authentication request. In addition, in WPC specification v1.2.2, it is stipulated that when TX 100 cannot correctly receive a packet in the negotiation phase, TX 100 will remain in the negotiation phase. Therefore, by resending the authentication request, if TX 100 correctly receives the packet and RX receives ACK or an undefined response, it is possible to continue the sequence. It can be set so that after sending the authentication request multiple times (about 3 times) in a row, if neither ACK nor an undefined response is received, EPT is sent.

[0119] As described above, in the negotiation phase in which the TX 100 is to return a response (undefined response) to a packet that it does not support, the RX 200 sends a packet to determine whether the TX 100 supports WPT authentication. Therefore, the RX 200 can determine whether the TX 100 supports WPT authentication based on the response to the authentication request, and can operate without conflict with respect to the TX that does not support WPT authentication.

[0120] The authentication request is sufficient as a packet that can expect a response (undefined response) from the conventional TX 100. Therefore, in the packet where a response can be expected and under the WPC specification v1.2.2, it may be a reserved packet whose packet type has not yet been defined. For example, a general request packet and a specific request packet are packets to which a response can be expected. More specifically, it may be a specific request packet in which the packet request field (0x05 to 0xEF) is reserved. In this case, if the TX 100 does not support WPT authentication, the TX 100 sends an undefined response, and the RX 200 receives the undefined response. Alternatively, it may be a general request packet in which the request field is reserved. In this case, if the TX 100 does not support WPT authentication, the TX 100 sends a power transmitter data unavailable packet in the same manner as the undefined response, which indicates that it lacks support as a response to the request, and the RX 200 receives the packet.

[0121] Alternatively, RX may exchange a packet for determining whether TX supports WPT authentication before sending an authentication request. For example, RX 200 may send a general request packet to request a power transmitter identification packet, which includes individual identification information and a specification version of TX 100. In this case, RX 200 acquires the specification version of TX 100 through a general request before sending an authentication request. If the acquired version information is version A or later, RX 200 may send an authentication request by determining that TX 100 supports WPT authentication. Otherwise, RX may determine that TX 100 does not support WPT authentication.

[0122] In addition, a request for a power transmitter capability packet storing capability information of the TX 100 may be made by sending the same general request packet to perform a power transmitter identification packet request. The power transmitter capability packet is a packet sent by the TX 100 as a power transmission device to notify the power receiving device of its power transmission capability, and information indicating the ability to perform WPT authentication may be included in the packet. In this case, in the WPC specification v1.2.2, in the power transmitter capability packet ( Fig. 10B ) or one of the bits from bit 7 to bit 2 of block 2 may be defined as an Auth bit by version A. "1 (WPT certification support)" or "0 (WPT certification not supported)" is written in the Auth bit. The TX 100 conforming to version A shall write "1 (WPT certification support)" in the Auth bit of the power transmitter capability group.

[0123] Furthermore, in order to receive a response to a reserved packet, the RX 200 will send a reserved packet when the TX 100 is in the negotiation phase. This allows the RX to determine whether the TX 100 is a legacy TX and whether the TX supports WPT certification by determining whether the response is an undefined response or an ACK. Since the TX 100 does not respond to a reserved packet in the WPC specification v1.2.2 even if the same packet is sent in the I&C phase, the above determination cannot be performed.

[0124] <Case 3 where TX is legacy TX and RX is version A>

[0125] An example has been described in which the RX 200 determines whether the TX 100 supports WPT authentication based on a response to an ACK(auth) or an authentication request. Fig. 9B Another example is described. Note that in the following explanation, it is assumed that the USB authentication operation for the USB cable 300 and the AC adapter 301 by the TX 100 has succeeded. After receiving the ACK in response to the configuration packet and switching to the negotiation phase, the RX 200 determines whether a specific packet sent from the TX 100 has been received within a predetermined time in the authentication phase. If the specific packet is received within the predetermined time, the RX 200 determines that the TX 100 supports WPT authentication. Otherwise, the RX determines that the TX 100 does not support WPT authentication.

[0126] Prior to the following explanation, the operation of the TX 100 supporting WPT authentication will be described. Once it is determined from the configuration packet that the RX 200 supports WPT authentication, the TX 100 transitions to the authentication phase. That is, the TX 100 sends the start of the acquisition summary packet to the RX 200 within a predetermined time from the trailing edge of the ACK to the configuration packet.

[0127] In the case where TX 100 is a conventional TX, since RX 200 does not receive the start of the Get Digest Packet within a predetermined time (No in step S911), RX determines that TX 100 does not support WPT authentication (step S908), and transitions to the negotiation phase. In this way, RX 200 operates without conflict with respect to conventional TX 100. If TX 100 supports WPT authentication, RX 200 receives at least the start of the Get Digest Packet within a predetermined time (Yes in step S911). Therefore, RX 200 determines that TX 100 supports WPT authentication (step S904), and transitions to the authentication phase (step S905).

[0128] Here, it is assumed in the present embodiment that the above-mentioned predetermined time is 6 milliseconds. In the WPC specification v1.2.2, it is stipulated that the RX 200 cannot send the start of any type of packet within 6 milliseconds after receiving the ACK. Therefore, if the TX 100 sends the start of the Get Digest Packet at least within 6 milliseconds, it is possible to make the RX 200 transition to the authentication phase before the RX 200 sends a packet (e.g., a specific request, etc.) to be sent in the negotiation phase.

[0129] As described above, when the TX 100 is a conventional TX and supports WPT certification, the RX 200 according to the present embodiment can operate without conflict.

[0130] <When RX is the initiator of WPT certification>

[0131] Fig. 8E An example in which TX 100 is the initiator is described. However, the present invention is not limited thereto, and RX 200 may be the initiator. In this case, since RX 200 determines that TX 100 supports WPT authentication by receiving ACK(auth), RX transitions to the authentication phase. RX 200 then transmits an acquisition summary packet to TX 100. The transmission of the acquisition summary packet and the subsequent authentication process (from 814 to 820) are performed in order. Fig. 8E The process is executed in the opposite direction of the corresponding packet arrow shown. RX 200 switches to the negotiation phase once it sends the result (success). In the same way, TX 100 switches to the negotiation phase once it receives the result (success). Even if the process is implemented in the above manner, the same effect can be clearly achieved.

[0132] In the case where TX 100 receives a packet other than a predetermined packet from RX 200 in the authentication phase, TX can stop the power transmission by the power transmission unit 103 and transition to the selection phase. The predetermined packet refers to the packets of 814 to 820, and is Get Digest (GET_DIGEST), Digest (DIGEST), Get Certificate (GET_CERTIFICATE), Certificate (CERTIFICATE), Challenge (CHALLENGE), Response (RESPONSE), and Result (RESULT). If a packet such as a signal strength packet indicating a voltage value of a received voltage, a control error packet requesting that a voltage value be increased / decreased, an ID packet, a configuration packet, etc. is received in the authentication phase, TX 100 stops power transmission and returns to the selection phase. In this way, when a packet other than a predetermined packet is received due to a malfunction of RX 200 or the like in the authentication phase, TX 100 can prevent an unexpected operation in the system by stopping power transmission.

[0133] As described above, in the contactless charging system according to the present embodiment, device authentication using the USB protocol is performed between the power supply device (AC adapter 301) as a power source and the power transmission device, and device authentication using the WPT protocol is performed between the power transmission device and the power receiving device. Subsequently, the transmission power of the WPC power transmission device is controlled based on the USB device authentication result and the WPT device authentication result. This arrangement can achieve preferred power transmission device control without the risk of overheating of the device present in the power supply path.

[0134] In addition, before starting power transmission from the WPC power transmission device to the power receiving device, the transmission power of the WPC power transmission device is limited based on the USB authentication result. This arrangement can achieve high-speed control because after the power transmission by the WPC power transmission device starts, renegotiation of the transmission power due to the limitation of the transmission power based on the USB authentication result will not occur.

[0135] <Other Examples>

[0136] The power transmission method of the wireless power transmission system according to the present invention is not particularly limited. A magnetic resonance method of transmitting power through magnetic resonance coupling between a resonator (resonance element) of TX and a resonator (resonance element) of RX may be adopted. Alternatively, a power transmission method using an electromagnetic induction method, an electric resonance method, a microwave method, a laser, etc. may be adopted.

[0137] TX and RX may each be, for example, an image input device such as a scanner or an image capture device (camera, video camera, etc.) or an image output device such as a printer, a copier, or a projector. A storage device such as a hard disk device or a memory device may be used as TX or RX, or an information processing device such as a personal computer (PC) or a smart phone may be used as TX or RX.

[0138] in addition, Figure 5 , Figure 7 and 9A to 9C Each of the flowcharts shown is started when the control unit is powered on. Figure 5 and Figure 7 Each of the illustrated processing operations is realized by the control unit 101 executing a program stored in the memory 107 of the TX 100 . 9A to 9C Each of the illustrated flowcharts is performed by the control unit 201 executing a program stored in the memory 209 of the RX 200 .

[0139] Note that Figure 5 , Figure 7 and 9A to 9CAt least some of the processes shown in the flowcharts of can be implemented by hardware. If the processes are to be implemented by hardware, for example, a dedicated circuit can be automatically generated on an FPGA from a program for implementing each step using a predetermined compiler. FPGA is an abbreviation for field programmable gate array. In addition, some of the processes can be implemented by forming a gate array circuit as hardware in the same manner as an FPGA.

[0140] The embodiments of the present invention may also be implemented by a computer of a system or device and a method performed by the computer of the system or device, the computer reading and executing computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more completely referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the embodiments described above, and / or including one or more circuits (e.g., application specific integrated circuits (ASICs)) for performing the functions of one or more of the embodiments described above, the method by, for example, reading and executing computer executable instructions from the storage medium to perform the functions of one or more of the embodiments described above, and / or controlling the one or more circuits to perform the functions of one or more of the embodiments described above. The computer may include one or more processors (e.g., central processing unit (CPU), microprocessing unit (MPU)) and may include a network of independent computers or independent processors to read and execute the computer executable instructions. The computer executable instructions may be provided to the computer from, for example, a network or the storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)). TM )), one or more of flash memory devices, memory cards, etc.

[0141] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0142] This application claims the benefit of Japanese Patent Application No. 2017-163671, filed on August 28, 2017, which is hereby incorporated by reference herein in its entirety.

Claims

1. A power receiving device, comprising: a transmitting means for transmitting, after receiving a digital Ping from the power transmitting device, to the power transmitting device an identification packet, a configuration packet to the power transmitting device, and a general request packet for requesting capabilities of the power transmitting device, the identification packet including identification information of the power receiving device, and the configuration packet including information indicating whether the power receiving device supports an authentication function; a negotiating component for negotiating with the power transmission device after receiving an acknowledgement of the configuration packet from the power transmission device; a receiving component, configured to receive a capability packet from the power transmission device in response to the transmitted general request packet, the capability packet including information indicating whether the power transmission device supports an authentication function; an authentication component configured to start an authentication process for the power transmission device if the power transmission device supports authentication, wherein the authentication component does not start the authentication process for the power transmission device if the power transmission device does not support authentication, and the authentication process includes transmitting, by the transmission component, a certificate acquisition packet; as well as The power receiving section is used to wirelessly receive power from the power transmitting device.

2. The power receiving device according to claim 1, wherein The get certificate packet is a packet for requesting information about a certificate.

3. The power receiving device according to claim 1 or 2, wherein: The authentication process includes an authentication process for confirming the validity of the power transmission device.

4. The power receiving device according to claim 1 or 2, wherein: Information indicating whether the power receiving device supports the authentication function is stored in bit 6 of chunk 2 configuring the packet.

5. The power receiving device according to claim 4, wherein: The information indicating that the power receiving device supports the authentication function is "1", and the information indicating that the power receiving device does not support the authentication function is "0".

6. A method for a power receiving device, the method comprising: After receiving a digital Ping from the power transmission device, transmitting to the power transmission device an identification packet, a configuration packet to the power transmission device, and a general request packet requesting capabilities of the power transmission device, the identification packet including identification information of the power receiving device, and the configuration packet including information indicating whether the power receiving device supports an authentication function; after receiving an acknowledgement of the configuration packet from the power transfer device, negotiating with the power transfer device; For the transmitted general request packet, receiving a capability packet from the power transmission device, the capability packet including information indicating whether the power transmission device supports an authentication function; starting an authentication process for the power transmission device if the power transmission device supports authentication, wherein the authentication process for the power transmission device is not started if the power transmission device does not support authentication, and the authentication process includes transmitting an acquisition credential packet; as well as Power is wirelessly received from a power transmission device.

7. The method according to claim 6, wherein: The authentication process includes an authentication process for confirming the validity of the power transmission device.

8. A storage medium storing a program for causing a computer to execute a method for a power receiving device, the method comprising: After receiving a digital Ping from the power transmission device, transmitting to the power transmission device an identification packet, a configuration packet to the power transmission device, and a general request packet requesting capabilities of the power transmission device, the identification packet including identification information of the power receiving device, and the configuration packet including information indicating whether the power receiving device supports an authentication function; after receiving an acknowledgement of the configuration packet from the power transfer device, negotiating with the power transfer device; For the transmitted general request packet, receiving a capability packet from the power transmission device, the capability packet including information indicating whether the power transmission device supports an authentication function; starting an authentication process for the power transmission device if the power transmission device supports authentication, wherein the authentication process for the power transmission device is not started if the power transmission device does not support authentication, and the authentication process includes transmitting an acquisition credential packet; as well as Power is wirelessly received from a power transmission device.

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