Wireless charging device and operating method thereof

Abstract

A first wireless charging device includes: an antenna and a power transmitter configured to charge an external device by transmitting power to the external device via the antenna; a near field communication (NFC) unit configured to detect whether the external device is a passive NFC device; a controller configured to control the power transmitter depending on an output of the NFC unit, where the output indicates whether the external device is a passive NFC device; and a decision unit configured to receive the NFC antenna load value from the second wireless charging device, and cause the NFC unit to detect whether the external device is a passive NFC device and cause the controller to control the power transmitter in a case where the load on the antenna is higher than the NFC antenna load value received from the second wireless charging device. According to a second aspect of the present disclosure, a corresponding method of operating a first wireless charging device is conceived.

Description

Technical Field

[0001] The present disclosure relates to a first wireless charging device. In addition, the present disclosure relates to a corresponding method of operating the first wireless charging device. In addition, the present disclosure relates to a charging system, the charging system comprising the first wireless charging device and the second wireless charging device. Background Art

[0002] A wireless charging system typically includes one or more wireless charging devices. For example, such a wireless charging device may include a low frequency (LF) power transmitter based on the Qi standard. Qi is an open interface standard that defines wireless power transfer using inductive charging at a distance of up to 4 cm; this standard has been developed by the Wireless Power Consortium (WPC). Therefore, in this case, the wireless charging device may also be referred to as a WPC device. In addition, the wireless charging device typically includes a near field communication unit (NFC), which is capable of detecting the presence and type of an external device that may be charged. More specifically, the NFC unit is capable of detecting the presence and type of an NFC-enabled device that is in close proximity to the wireless charging device. Specifically, the external device may be a passive NFC device (e.g., a tag or transponder) or an active, typically battery-powered NFC device. Summary of the invention

[0003] According to a first aspect of the present disclosure, there is provided a first wireless charging device, comprising: an antenna and a power transmitter, the power transmitter being configured to charge an external device by transmitting power to the external device via the antenna; a near field communication (NFC) unit, the NFC unit being configured to detect whether the external device is a passive NFC device; a controller being configured to control the power transmitter depending on an output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device; and a decision unit being configured to receive an NFC antenna load value from a second wireless charging device, and, if a load on the antenna is higher than the NFC antenna load value received from the second wireless charging device, cause the NFC unit to detect whether the external device is a passive NFC device and cause the controller to control the power transmitter.

[0004] In one or more embodiments, the controller is further configured to prevent the power transmitter from charging the external device if the NFC unit has detected that the external device is a passive NFC device, or to reduce the amount of power transmitted by the power transmitter if the NFC unit has detected that the external device is a passive NFC device.

[0005] In one or more embodiments, the controller is further configured to permit the power transmitter to charge the external device if the NFC unit has detected that the external device is not a passive NFC device.

[0006] In one or more embodiments, the power transmitter is a low frequency (LF) power transmitter configured to transfer power to the external device.

[0007] In one or more embodiments, the LF power transmitter is a Qi based LF power transmitter.

[0008] In one or more embodiments, the decision unit is further configured to receive timing data from the second wireless charging device and cause the NFC unit to detect whether the external device is a passive NFC device and cause the controller to control the power transmitter depending on the timing data.

[0009] In one or more embodiments, the timing data includes a time slot in which the second wireless charging device performs detection for detecting whether the external device is a passive NFC device.

[0010] In one or more embodiments, the decision unit is configured to prevent the NFC unit from detecting whether the external device is a passive NFC device and to prevent the controller from controlling the power transmitter in the time slot.

[0011] In one or more embodiments, the NFC unit is additionally configured to operate in a low-power object detection mode in order to detect the presence of the external device.

[0012] In one or more embodiments, the decision unit is configured to wake up the NFC unit if the presence of the external device is detected and the load on the antenna is higher than the NFC antenna load value received from the second wireless charging device.

[0013] In one or more embodiments, the decision unit is configured to receive the NFC antenna load value from the second wireless charging device through a pre-established communication channel.

[0014] In one or more embodiments, the communication channel is based on a Controller Area Network with Flexible Data-rate (CAN FD) communication protocol.

[0015] In one or more embodiments, a charging system includes a first wireless charging device of the type described and a second wireless charging device, wherein the second wireless charging device is configured to transmit an NFC antenna load value to the first wireless charging device, the NFC antenna load value indicating a load on an NFC antenna integrated into the second wireless charging device.

[0016] In one or more embodiments, a vehicle includes a charging system of the kind set forth.

[0017] According to a second aspect of the present disclosure, a method of operating a first wireless charging device is contemplated, the device comprising an antenna, a power transmitter, a near field communication (NFC) unit, a controller, and a decision unit, the method comprising: receiving, by the decision unit, an NFC antenna load value from a second wireless charging device; in a case where the load on the antenna is higher than the NFC antenna load value received from the second wireless charging device, causing, by the decision unit, the NFC unit to detect whether an external device is a passive NFC device and causing the controller to control the power transmitter; and controlling, by the controller, the power transmitter depending on an output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments will be described in more detail with reference to the accompanying drawings.

[0019] Figure 1 An illustrative embodiment of a first wireless charging apparatus is shown.

[0020] Figure 2 An illustrative embodiment of a charging system is shown.

[0021] Figure 3 An illustrative embodiment of a method of operating a first wireless charging device is shown.

[0022] Figure 4 An illustrative embodiment of a communication flow is shown.

[0023] Figure 5 Another illustrative embodiment of a communication flow is shown.

[0024] Figure 6 Additional illustrative embodiments of communication flows are shown.

[0025] Figure 7 An illustrative embodiment of a method of operating a WPC device is shown.

[0026] Fig. 8A Another illustrative embodiment of a method of operating a WPC device is shown.

[0027] Figure 8BThe received amplitude of the first WPC device is shown.

[0028] Figure 8C The received amplitude of the second WPC device is shown. DETAILED DESCRIPTION

[0029] Modern vehicles may be equipped with multiple wireless charging devices, such as Qi-based wireless charging devices, which are placed close to each other and support charging between 15 watts and 80 watts. However, for transmitted power above 5 watts, external devices that are accidentally in close proximity to the charging device may be damaged. For example, if a smart card is exposed to such high transmitter power levels, the smart card may be damaged (e.g., burned out). Therefore, a so-called card protection algorithm may be implemented. Such an algorithm has been described in European patent application EP 4 207 614 A1. This algorithm distinguishes between passive NFC devices (e.g., cards, tags, or transponders) and active NFC devices, and prevents charging or reduces the amount of power transmitted by the charging device if the external device is a passive NFC device. As used herein, the term "passive device" refers to a device that does not have a battery but is powered by a field. It should be noted that a passive device may include one or more storage elements for temporarily storing energy extracted from the field. In contrast, the term "active device" refers to a device with an internal power source such as a battery.

[0030] The cost of wireless charging devices has decreased. For this reason, the use of multiple wireless charging devices in close proximity to each other has increased. For example, in a vehicle, a wireless charging device may be provided for the driver, while another wireless charging device may be provided for the passenger sitting next to the driver. In this case, the two wireless charging devices may be integrated into a console located between the driver and the passenger. Subsequently, both wireless charging devices will be equipped with an NFC antenna, with the help of which the type of external device (i.e., passive or active) can be determined so that the aforementioned card protection algorithm can be implemented. However, in this case, the two NFC antennas may be too close to each other to make it difficult to determine whether a particular external device is placed on the first wireless charging device or on the second wireless charging device. This in turn makes it difficult to determine which of the two wireless charging devices should activate its card protection algorithm.

[0031] A first wireless charging device having an improved ability to determine whether it should activate its card protection algorithm is now discussed. In addition, a corresponding method of operating the first wireless charging device is discussed.

[0032] Figure 1An illustrative embodiment of a first wireless charging device 100 is shown. The first wireless charging device 100 includes an antenna 102, a power transmitter 104, an NFC unit 106, an NFC antenna 112, a controller 108, and a decision unit 110. The power transmitter 104 is configured to charge the external device (not shown) by transmitting power to the external device via the antenna. In addition, the NFC unit 106 is configured to detect whether the external device is a passive NFC device. In addition, the controller 108 is configured to control the power transmitter depending on the output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device. Thus, the NFC unit 106 and the controller 108 implement a so-called card protection algorithm. In addition, the decision unit 110 is configured to receive an NFC antenna load value from a second wireless charging device (not shown), and in the case where the load on the antenna 102 is higher than the NFC antenna load value received from the second wireless charging device, the NFC unit 106 detects whether the external device is a passive NFC device and the controller 108 controls the power transmitter. In this way, the card protection algorithm implemented by the NFC unit 106 and the controller 108 is activated only if there is a possibility that the external device is closer to the first wireless charging device 100 than to the second wireless charging device. In other words, the first wireless charging device 100 has an improved ability to determine whether it should activate its card protection algorithm. It should be noted that the term "NFC antenna load value" may refer to any kind of value that indicates the load on the NFC antenna. Such a value may, for example, consist of the output of a current measurement performed on the NFC antenna, as shown in Table 1.

[0033] In one or more embodiments, the controller is further configured to prevent the power transmitter from charging the external device if the NFC unit has detected that the external device is a passive NFC device, or to reduce the amount of power transmitted by the power transmitter if the NFC unit has detected that the external device is a passive NFC device. This helps to avoid damage to the external device because it can be ensured that excessive power is not transmitted to the passive NFC device. In one or more embodiments, the controller is further configured to allow the power transmitter to charge the external device if the NFC unit has detected that the external device is not a passive NFC device. In this way, the charging process can start relatively quickly after verifying that the external device is unlikely to be damaged. In a practical implementation, the power transmitter is a low frequency (LF) power transmitter configured to transmit power to the external device. For example, the LF power transmitter may be a Qi-based LF power transmitter.

[0034] In one or more embodiments, the decision unit is further configured to receive timing data from the second wireless charging device, and to cause the NFC unit to detect whether the external device is a passive NFC device and to cause the controller to control the power transmitter depending on the timing data. In this way, conflicts with NFC transmissions performed by the second wireless charging device can be more easily avoided. For example, the second wireless charging device can also decide to start a card protection algorithm involving NFC. In this case, the NFC transmission of the first wireless charging device can be synchronized with the NFC transmission of the second wireless charging device to avoid conflicts or mutual interference. In a practical implementation, the timing data includes a time slot in which the second wireless charging device performs a detection for detecting whether the external device is a passive NFC device. In addition, in a practical implementation, the decision unit is configured to prevent the NFC unit from detecting whether the external device is a passive NFC device and to prevent the controller from controlling the power transmitter in the time slot. Therefore, the decision unit effectively prevents the first wireless charging device from executing a card protection algorithm involving NFC in a time slot in which the second wireless charging device executes an algorithm similar to the card protection algorithm involving NFC.

[0035] In one or more embodiments, the NFC unit is further configured to operate in a low-power object detection mode in order to detect the presence of the external device. In this way, the presence of the external device can be detected at low power before detecting whether the external device is a passive NFC device. In one or more embodiments, the decision unit is configured to wake up the NFC unit when the presence of the external device is detected and the load on the antenna is higher than the NFC antenna load value received from the second wireless charging device. In this way, the NFC unit is woken up only when necessary, specifically, to detect whether the external device is a passive NFC device. In a practical implementation, the decision unit is configured to receive the NFC antenna load value from the second wireless charging device via a pre-established communication channel. In addition, in a practical implementation, the communication channel is based on a controller area network with flexible data rate (CAN FD) communication protocol. In this way, a communication channel commonly used in vehicles, for example, is used to transmit the NFC antenna load value so that no additional communication infrastructure may be required.

[0036] Figure 2An illustrative embodiment of a charging system 200 is shown. The charging system 200 includes a first wireless charging device 100 of the type set forth above and a second wireless charging device 202. It should be noted that the second wireless charging device 202 may include the same components as the first wireless charging device 100. The second wireless charging device 202 is configured to transmit an NFC antenna load value to the first wireless charging device using the CAN FD communication protocol 204. The NFC antenna load value indicates a load on an NFC antenna (not shown) integrated into the second wireless charging device 202. In this way, a charging system 200 is provided that includes a plurality of wireless charging devices 100, 202 having an improved ability to determine which of the charging devices 100, 202 should activate a built-in card protection algorithm.

[0037] Figure 3 An illustrative embodiment of a method 300 for operating a first wireless charging device is shown. The method 300 includes the following steps. At 302, a decision unit of the first wireless charging device receives an NFC antenna load value from a second wireless charging device. In addition, at 304, in the case where the load on the antenna of the first wireless charging device is higher than the NFC antenna load value received from the second wireless charging device, the decision unit causes the NFC unit of the first wireless charging device to detect whether the external device is a passive NFC device and causes the controller of the first wireless charging device to control the power transmitter of the first wireless charging device. In addition, at 306, the controller controls the power transmitter depending on the output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device. As mentioned above, in this way, the card protection algorithm implemented by the NFC unit and the controller of the first wireless charging device is activated only when there is a possibility that the external device is closer to the first wireless charging device than to the second wireless charging device.

[0038] At least some of the above embodiments facilitate scheduling of NFC active time to avoid interference between NFC readers integrated into wireless charging devices. Specifically, parallel activation of the NFC readers can be avoided, which may lead to erroneous NFC detection. In addition, external NFC devices can be located based on load conditions (e.g., antenna current, received signal strength indicator, and I / Q amplitude characteristics). Thus, for example, it can be determined on which NFC reader the card has been placed, or whether the card is placed between NFC readers. In addition, based on positioning and time synchronization (i.e., scheduling), more reliable card protection can be performed. When the charging system is integrated into a vehicle, the presence of a second wireless charging device can be "learned" during a line end test or during a power-on phase in the vehicle. More specifically, in order to achieve NFC positioning and NFC scheduling, the first wireless charging device can be notified that a second wireless charging device exists or may exist. For example, this can be done after the vehicle is powered.

[0039] In an example, two wireless charging devices including NFC readers may be placed close to each other. The wireless charging devices may include WPC (Qi) and may be connected to the same CAN / power domain. During a learning phase, such as during end-of-line testing when installing the wireless charging device in a vehicle, the devices may be synchronized via an out-of-band radio (e.g., CAN or LIN). Specifically, data indicating the presence, location (i.e., driver (WPC 1) or passenger (WPC 2) location) and timing synchronization of the second wireless charging device may be shared. Alternatively, these data may always be allocated during powering the module. For example, a first wireless charging device (WPC 1) may send a synchronization request via CAN, and if a second wireless charging device (WPC 2) is already connected, the second wireless charging device may respond with synchronization confirmation. Subsequently, during a normal operation phase, in order to avoid conflicts or interference between NFC readers, scheduling of active NFC may be applied. This scheduling activity may start after power-on. For example, CAN synchronization requests and synchronization confirmations may be used for scheduling.

[0040] Figure 4An illustrative embodiment of a communication flow 400 is shown. The communication flow 400 involves a first WPC device 402, a second WPC device 404, and a mobile device 406. Specifically, the communication flow 400 shows a first use case scenario, in which a mobile device 406 (e.g., a phone) is placed on the second WPC device 404. Both WPC devices 402, 404 are integrated into a vehicle such as a car. In order to save current consumption, the first WPC device 402 and the second WPC device 404 can be connected to a power domain, which is disabled when the car is in a power-off mode. In the case where the car enters an on mode, the first WPC device 402 and the second WPC device 404 can be turned on by powering on the power domain. After powering on, a time synchronization process is started to ensure that there is no mutual interference between the first WPC device 402 and the second WPC device 404. Specifically, the first WPC device 402 sends a synchronization request to the second WPC device 404 via a controller area network (CAN). This synchronization request is used by the second WPC device 404 to synchronize an internal timer. Then, the second WPC device 404 confirms synchronization through confirmation. Then, the first WPC device 402 uses this confirmation to perform internal timer synchronization.

[0041] The first WPC device 402 and the second WPC device 404 may enter low power barrier detection using known methods, such as ultra low power card detection (uLPCD). As mentioned above, the first WPC device 402 and the second WPC device 404 are time synchronized to avoid NFC conflicts or interference. After the first WPC device 402 detects an object near it, it may perform a so-called "presence check". This presence check is performed by transmitting low-level commands for each type of NFC technology (e.g., ReqA, ReqB, etc.). During the presence check, the load (e.g., antenna current) and received signal strength are measured. The first WPC device 402 shares this information with the second WPC device 404. The second WPC device 404 has also detected an object, performs the same check and shares information with the first WPC device 402. By comparing the information from the first WPC device 402 and the second WPC device 404, it can be determined that the object (i.e., the mobile device 406) has been placed on the second WPC device 404. Therefore, the second WPC device 404 can activate its card protection algorithm. This algorithm determines that the object is an active NFC device, for example, by applying a digital or analog sensing method or analyzing reverse link characteristics. Since the object is an active NFC device, the second WPC device 404 allows charging and sends a Qi digital notification (ping). Finally, the second WPC device 404 sends a synchronization confirmation to the first WPC device 402, and the first WPC device 402 will start object detection again based on the agreed time grid and can use the synchronization confirmation for timer synchronization.

[0042] Figure 5 Another illustrative embodiment of a communication flow 500 is shown. The communication flow 500 involves a first WPC device 502, a second WPC device 504, and a card 506. Specifically, the communication flow 500 shows a second use case scenario, in which the card 506 is placed on the second WPC device 504. Both WPC devices 502, 504 are integrated into a vehicle such as a car. In order to save current consumption, the first WPC device 502 and the second WPC device 504 can be connected to a power domain, which is disabled when the car is in a power-off mode. In the case where the car enters an on mode, the first WPC device 502 and the second WPC device 504 can be turned on by powering on the power domain. After powering on, a time synchronization process is started to ensure that there is no mutual interference between the first WPC device 502 and the second WPC device 504. Specifically, the first WPC device 502 sends a synchronization request to the second WPC device 504 via CAN. This synchronization request is used by the second WPC device 504 to synchronize the internal timer. Subsequently, the second WPC device 504 confirms synchronization by confirmation. The first WPC device 502 then uses this confirmation to perform internal timer synchronization.

[0043] The first WPC device 502 and the second WPC device 504 can enter low power barrier detection using known methods (e.g., uLPCD). As mentioned above, the first WPC device 502 and the second WPC device 504 are time synchronized to avoid NFC conflicts or interference. After the first WPC device 502 detects an object near it, it can perform a presence check. This presence check is performed by transmitting low-level commands for each type of NFC technology (e.g., ReqA, ReqB, etc.). During the presence check, the load (e.g., antenna current) and received signal strength are measured. The first WPC device 502 shares this information with the second WPC device 504. The second WPC device 504 has also detected an object, performs the same check and shares information with the first WPC device 502. By comparing the information from the first WPC device 502 and the second WPC device 504, it can be determined that the object (i.e., card 506) has been placed on the second WPC device 504. Therefore, the second WPC device 504 can activate its card protection algorithm. This algorithm determines that the object is a passive NFC device, for example, by applying a digital or analog sensing method or analyzing reverse link characteristics. Since the object is a passive NFC device, the second WPC device 504 blocks charging. Finally, the second WPC device 504 sends a synchronization confirmation to the first WPC device 502, and the first WPC device 502 will start object detection again based on the agreed time grid and can use the synchronization confirmation for timer synchronization.

[0044] Figure 6Another illustrative embodiment of the communication flow 600 is shown. The communication flow 600 involves a first WPC device 602, a second WPC device 606, a card 604, and a mobile device 608 (e.g., a phone). Specifically, the communication flow 600 shows a third use case scenario, in which the mobile device 608 is placed on the second WPC device 606 and the card 604 is placed on the first WPC device 602. Both WPC devices 602, 606 are integrated into a vehicle such as a car. In order to save current consumption, the first WPC device 602 and the second WPC device 606 can be connected to a power domain, which is disabled when the car is in a power-off mode. In the case where the car enters an on mode, the first WPC device 602 and the second WPC device 606 can be turned on by powering on the power domain. After powering on, a time synchronization process is started to ensure that there is no mutual interference between the first WPC device 602 and the second WPC device 606. Specifically, the first WPC device 602 sends a synchronization request to the second WPC device 606 via CAN. This synchronization request is used by the second WPC device 606 to synchronize the internal timer. The second WPC device 606 then confirms the synchronization through a confirmation. The first WPC device 602 then uses this confirmation to perform internal timer synchronization.

[0045] The first WPC device 602 and the second WPC device 606 can enter low power barrier detection using known methods (e.g., uLPCD). As mentioned above, the first WPC device 602 and the second WPC device 606 are time synchronized to avoid NFC conflicts or interference. After the first WPC device 602 detects an object near it, it can perform a presence check. This presence check is performed by transmitting low-level commands for each type of NFC technology (e.g., ReqA, ReqB, etc.). During the presence check, the load (e.g., antenna current) and received signal strength are measured. The first WPC device 602 shares this information with the second WPC device 606. The second WPC device 606 has also detected an object, performs the same check and shares information with the first WPC device 602. By comparing the information from the first WPC device 602 and the second WPC device 606, it can be determined that the object (i.e., the mobile device 608) has been placed on the second WPC device 606. Therefore, the second WPC device 606 can activate its card protection algorithm. This algorithm determines that the object is an active NFC device, for example, by applying a digital or analog sensing method or analyzing reverse link characteristics. Since the object is an active NFC device, the second WPC device 606 allows charging and sends a Qi digital notification. Subsequently, the second WPC device 606 sends a synchronization confirmation to the first WPC device 602, and the first WPC device 602 will start object detection again based on the agreed time grid and can use the synchronization confirmation for timer synchronization.

[0046] Subsequently, the first WPC device 602 detects another object and performs the above-mentioned presence check. Then, the first WPC device 602 shares this information with the second WPC device 606. In addition, the second WPC device 606 shares information with the first WPC device 602, which indicates the fact that the second WPC device 606 has not detected another object. Therefore, the first WPC device 602 can activate its card protection algorithm. This algorithm determines that the object is a passive NFC device. Since the object is a passive NFC device, the first WPC device 602 blocks charging and then returns to the object detection mode.

[0047] In order to determine which WPC device the NFC object is placed on, the load of the NFC antenna of the WPC device can be evaluated. Since the NFC object will detune the NFC antenna, the current driving the antenna will change. Therefore, the current of the antenna can be measured to check whether it is loaded. Even if the antennas can be placed close to each other, an NFC object placed on the first WPC device (WPC 1) will not affect the load of the NFC antenna of the second WPC device (WPC 2), and vice versa. This method of NFC object positioning is extremely reliable for different scenarios, as shown in Table 1. In the table, three different scenarios are shown. In the first scenario, no NFC object is placed on either WPC device. In the second scenario, an NFC-enabled mobile phone is placed on WPC 1, and no NFC object is placed on WPC 2. In the third scenario, an NFC-enabled mobile phone is placed on WPC 1, and an NFC card is placed on WPC 2.

[0048]

[0049] Table 1

[0050] Figure 7 An illustrative embodiment of a method 700 of operating a WPC device is shown. The method 700 begins at 702. At 704, a polling operation is performed by the WPC device. At 706, a low power card detection or current measurement is performed by the WPC device. If the output of this operation exceeds a predefined threshold 708, an analog sensing 712 operation is performed to determine whether the detected object is a passive NFC device (e.g., a card). As mentioned above, this analog sensing 712 operation can determine the load on the antenna of the WPC device. If the output of this operation is that a card is present, charging is prohibited 714. Otherwise, or if the output of the operation performed at 706 is below the threshold 708, charging is allowed 710.

[0051] Specifically, if it is determined that the NFC object is placed on the WPC device, the card protection algorithm is started. The result of the algorithm indicates whether the NFC object is a passive NFC device. If it is determined that the NFC object is a passive NFC device, charging will be blocked. On the other hand, if it is determined that the NFC object is an active NFC device, charging will be allowed. In the first scenario above, the card protection algorithm will not be started by any WPC device. In the second scenario, the card protection algorithm will be executed only for WPC 1. Since the NFC object placed on WPC 1 is a mobile phone, the result of the card protection algorithm will be to allow charging. In the third scenario, two WPC devices will execute the card protection algorithm. Since the mobile phone is placed on WPC 1, the card protection algorithm executed by WPC 1 will allow charging. However, since the NFC card is placed on WPC 2, the card protection algorithm executed by WPC 2 will prohibit charging.

[0052] Fig. 8A Another illustrative embodiment of a method 800 of operating a WPC device is shown. The method 800 begins at 802. At 804, a synchronization operation is performed by the WPC device. At 806, a polling operation is performed by the WPC device. At 808, the received I and Q amplitudes are measured, and at 810, the modulation level of the WPC device is compared with the modulation level reported by the other WPC device. If the WPC device has the highest modulation level of the two devices, then it can be concluded 812 that it applies passive load modulation (PLM). In this case, it can also be concluded that the WPC device is a passive NFC device, such as a card. Subsequently, charging is prohibited 816. Otherwise, it can be concluded 812 that the WPC device applies active load modulation (ALM), and charging can be allowed 814.

[0053] Figure 8B and 8C The received amplitude 818 of the first WPC device and the received amplitude 820 of the second WPC device are shown respectively. Specifically, Figures 8A to 8C shows how the third scenario described above can be solved by comparing the amplitudes of the received modulations. Figure 8B and 8C The time index is shown on the x-axis of and the amplitude index is shown on the y-axis. The amplitude of the modulation can be obtained by analyzing the output data of the I and Q receivers of the NFC device. The card / tag device uses PLM, while the NFC reader device that emulates a card (e.g., a mobile phone) uses ALM, and thus the two devices can be easily distinguished from each other. In a third scenario, the two WPC devices can measure the amplitude of the received modulation and compare it to each other. Figure 8B and 8CAn example of the received amplitude measurement in this scenario is shown. It can be seen that the card response is much higher on WPC 2. Therefore, it can be concluded that WPC 2 should prohibit charging and WPC 1 should allow charging.

[0054] It should be noted that the above embodiments have been described with reference to different subject matters. Specifically, some embodiments may have been described with reference to method claims, while other embodiments may have been described with reference to apparatus claims. However, those skilled in the art will appreciate from the foregoing that, unless otherwise stated, any combination of features relating to different subject matters, specifically combinations of features of method claims and features of apparatus claims, in addition to any combination of features belonging to one type of subject matter, are also deemed to be disclosed with this document.

[0055] In addition, it should be noted that the drawings are schematic. In different drawings, similar or identical elements have the same reference numerals. In addition, it should be noted that in order to provide a concise description of the illustrative embodiments, the implementation details that are customary to those skilled in the art may not be described. It should be understood that in the development process of any such implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the developer's specific goals, such as subjecting system-related and business-related constraints, which may be different in different implementations. In addition, it should be understood that such development work may be complex and time-consuming, but it is nothing more than a routine task for those skilled in the art to design, manufacture and produce.

[0056] Finally, it should be noted that a person skilled in the art should be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference numerals placed between parentheses should not be interpreted as limiting the claims. The words "comprise(s)" or "comprising" do not exclude the presence of other elements or steps than those listed in the claim. The words "a" or "an" preceding an element do not exclude the presence of a plurality of such elements. The measures recited in the claims may be implemented by means of hardware comprising several different elements and / or by means of a suitably programmed processor. In a device claim listing several components, several of these components may be embodied by the same hardware item. The fact that certain measures are recited in mutually different dependent claims does not mean that a combination of these measures cannot be used to advantage.

[0057] Reference numerals list

[0058] 100 The first wireless charging device

[0059] 102 Antenna

[0060] 104 Power Transmitter

[0061] 106 NFC unit

[0062] 108 Controller

[0063] 110 Decision Making Unit

[0064] 112 NFC Antenna

[0065] 200 Charging System

[0066] 202 Second wireless charging device

[0067] 204CAN FD Communication Protocol

[0068] 300 Method for operating a first wireless charging device

[0069] 302: The decision unit of the first wireless charging device receives the NFC antenna load value from the second wireless charging device.

[0070] 304, when the load on the antenna of the first wireless charging device is higher than the NFC antenna load value received from the second wireless charging device, the decision unit enables the NFC unit of the first wireless charging device to detect whether the external device is a passive NFC device and enables the controller of the first wireless charging device to control the power transmitter of the first wireless charging device.

[0071] 306 Controlling the power transmitter by the controller depending on the output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device

[0072] 400 communication flow

[0073] 402 First WPC Device

[0074] 404 Second WPC Device

[0075] 406 Mobile Device

[0076] 500 communication flows

[0077] 502 First WPC Device

[0078] 504 Second WPC Device

[0079] 506 card

[0080] 600 communication flow

[0081] 602 First WPC Device

[0082] 604 cards

[0083] 606 Second WPC Device

[0084] 608 mobile device

[0085] 700 Method of operating a WPC device

[0086] 702 Start

[0087] 704 Polling

[0088] 706LPCD / Current Measurement

[0089] 708x>ref+ / -threshold

[0090] 710 Charging allowed

[0091] 712 Analog Sensing

[0092] 714 Charging prohibited

[0093] 800 Method of operating a WPC device

[0094] 802 Start

[0095] 804 Synchronization

[0096] 806 Polling

[0097] 808 measures I and Q-Rcv amplitude

[0098] 810 Compare modulation levels

[0099] 812 Highest PLM

[0100] 814 Charging allowed

[0101] 816 Charging prohibited

[0102] 818 The received amplitude of the first WPC device

[0103] 820 Received amplitude of the second WPC device.

Claims

1. A first wireless charging device, characterized in that: include: an antenna and a power transmitter configured to charge an external device by transmitting power to the external device via the antenna; a near field communication (NFC) unit configured to detect whether the external device is a passive NFC device; a controller configured to control the power transmitter depending on an output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device; a decision unit configured to receive an NFC antenna load value from a second wireless charging device, and, if a load on the antenna is higher than the NFC antenna load value received from the second wireless charging device, cause the NFC unit to detect whether the external device is a passive NFC device and cause the controller to control the power transmitter.

2. The device according to claim 1, characterized in that The controller is additionally configured to prevent the power transmitter from charging the external device if the NFC unit has detected that the external device is a passive NFC device, or to reduce an amount of power transmitted by the power transmitter if the NFC unit has detected that the external device is a passive NFC device.

3. The device according to claim 1 or 2, characterized in that: The controller is additionally configured to permit the power transmitter to charge the external device if the NFC unit has detected that the external device is not a passive NFC device.

4. A device according to any of the preceding claims, characterised in that The power transmitter is a low frequency (LF) power transmitter configured to transmit power to the external device.

5. The device according to claim 4, characterized in that The LF power transmitter is a Qi-based LF power transmitter.

6. A device according to any of the preceding claims, characterised in that The decision unit is further configured to receive timing data from the second wireless charging device and to cause the NFC unit to detect whether the external device is a passive NFC device and to cause the controller to control the power transmitter depending on the timing data.

7. The device according to claim 6, characterized in that The timing data includes a time slot in which the second wireless charging device performs detection for detecting whether the external device is a passive NFC device.

8. A charging system, characterized in that: Comprising a first wireless charging device according to any preceding claim and a second wireless charging device, wherein the second wireless charging device is configured to transmit an NFC antenna load value to the first wireless charging device, the NFC antenna load value indicating a load on an NFC antenna integrated into the second wireless charging device.

9. A vehicle, characterized in that: Comprising a charging system according to claim 8.

10. A method for operating a first wireless charging device, characterized in that: The device includes an antenna, a power transmitter, a near field communication (NFC) unit, a controller, and a decision unit. The method includes: The decision unit receives an NFC antenna load value from a second wireless charging device; In a case where the load on the antenna is higher than the NFC antenna load value received from the second wireless charging device, the decision unit enables the NFC unit to detect whether the external device is a passive NFC device and enables the controller to control the power transmitter; The power transmitter is controlled by the controller depending on an output of the NFC unit, wherein the output indicates whether the external device is a passive NFC device.

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