Method and apparatus for identifying presence of near field communication (NFC) card or interference from poller or listener of multi-poller NFC wireless charging system

Abstract

Wireless charging includes suspending a monitor in response to communication from a poller, wherein the poller and the monitor form a charging pair. The poller then transmits a plurality of requests in response to suspending the communication with the listener, and receives corresponding responses to the plurality of requests. At least one corresponding response to the plurality of requests is received, and a number of bits in the received response that are erroneous compared to an expected sequence of bits of the response to the transmitted request is counted. A determination is made as to whether a near field communication (NFC) card is proximate to the wireless charger based on the counting of the number of bits, and the wireless charging is performed based on the determination.

Description

Technical Field

[0001] The present disclosure relates generally to near field communication (NFC), and more particularly to identifying the presence of an NFC card or interference from a poller or listener of a multi-poller NFC wireless charging system. Background Art

[0002] Wireless charging systems rely on wireless charging transmitters called pollers and wireless charging receivers called listeners. The listener is coupled to a battery and device circuitry, where the listener, battery, and device circuitry form a device such as earbuds, virtual reality glasses, etc. A wireless charging system may include multiple pollers and multiple listeners to facilitate wireless charging. The poller transmits a wireless charging signal, and the listener receives the wireless charging signal and uses the signal to charge the battery. Near field communication (NFC) technology is a short-range wireless technology that facilitates wireless communication between NFC-compatible devices such as NFC cards in addition to wireless charging. Wireless charging systems that implement NFC technology typically detect the presence of an NFC card before or during wireless charging, and based on this detection, stop wireless charging to prevent damage to the NFC card or the wireless charging system. Summary of the invention

[0003] According to a first aspect of the present invention, there is provided a method for wireless charging by a wireless charging system, the method comprising:

[0004] pausing a listener to respond to a plurality of requests to communicate with a poller, wherein the poller and the listener of the system form a wireless charging pair;

[0005] transmitting, by the poller, the plurality of requests in response to pausing the communication with the listener;

[0006] receiving at least one corresponding response to the plurality of requests;

[0007] counting a number of bits in the received response that are in error compared to an expected bit sequence for a response to the transmitted request, wherein the count is greater than one;

[0008] determining whether a near field communication (NFC) card is in proximity to a wireless charger based on the count of the number of bits; and

[0009] The wireless charging of the system is performed based on the determination.

[0010] In one or more embodiments, transmitting the plurality of requests comprises transmitting a first REQ(x) defined by the International Organization for Standardization / International Electrotechnical Commission (ISO / IEC) 14443-3 NFC standard; wherein counting the number of bits comprises determining a number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard.

[0011] In one or more embodiments, the method further comprises recording the position of the bit in error in the expected bit sequence of the ATQ(x) response to the first REQ(x).

[0012] In one or more embodiments, transmitting the plurality of requests comprises transmitting a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein counting the number of bits comprises determining that the number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard is greater than a threshold number of bits, and wherein performing the wireless charging comprises stopping the wireless charging.

[0013] In one or more embodiments, "x" indicates a request and a response corresponding to one of a Type A NFC card, a Type B NFC card, or a Type C NFC card defined by the ISO / IEC 14443-3 NFC standard.

[0014] In one or more embodiments, transmitting the multiple requests includes transmitting a first REQ(x) followed by a second REQ(x) defined by the ISO14443-3 NFC standard; wherein counting the number of bits includes determining that the number of erroneous bits in each of the first received response and the second received response is greater than a threshold number of bits compared to the corresponding expected bit sequences of the first ATQ(x) response and the second ATQ(x) response to the first REQ(x) and the second REQ(x).

[0015] In one or more embodiments, transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x), and wherein counting the number of bits includes determining that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and wherein performing the wireless charging includes not stopping the charging.

[0016] In one or more embodiments, transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is less than the threshold number of bits, and wherein performing the wireless charging includes stopping the wireless charging.

[0017] In one or more embodiments, transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and determining the positions of the bits in the third received response that are erroneous compared to the expected bit sequence of the ATQ(x) response to the third REQ(x), wherein adjusting the wireless charging includes stopping the wireless charging based on the position of the bits in the third received response being the same as the position of the bits in the first received response to the first REQ(x) that are erroneous compared to the expected bit sequence of the ATQ(x) response to the first REQ(x).

[0018] In one or more embodiments, performing the wireless charging includes reducing wireless charging power or stopping the wireless charging, wherein the wireless charging is based on the Wireless Charging Technical Specification Version 2.0 defined by the NFC Forum.

[0019] According to a second aspect of the present invention, there is provided a wireless charging system, comprising:

[0020] Poller;

[0021] a listener, wherein the listener and the poller form a wireless charging pair;

[0022] The poller is arranged to: suspend the listener from responding to multiple requests communicated with the poller, wherein the poller and the listener of the system form a wireless charging pair; transmit the multiple requests by the poller in response to suspending the communication with the listener; receive at least one corresponding response to the multiple requests; compare the bits of the received response with the expected bit sequence of the response to the transmitted request; count the number of bits in the received response that are erroneous compared to the expected bit sequence of the response to the transmitted request, wherein the count is greater than one; determine whether an NFC card is close to a wireless charger based on the count of the number of bits; and perform the wireless charging of the system based on the determination.

[0023] In one or more embodiments, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine a number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard.

[0024] In one or more embodiments, the system further includes recording the position of the bit in error in the expected bit sequence of the ATQ(x) response to the first REQ(x).

[0025] In one or more embodiments, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein the poller being arranged to count a number of bits comprises the poller being arranged to determine that the number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard is less than a threshold number of bits, and wherein the poller being arranged to perform the wireless charging comprises the poller being arranged to stop the wireless charging.

[0026] In one or more embodiments, "x" indicates a request and a response corresponding to one of a Type A NFC card, a Type B NFC card, or a Type C NFC card defined by the ISO / IEC 14443-3 NFC standard.

[0027] In one or more embodiments, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) followed by a second REQ(x) defined by the ISO14443-3 NFC standard; wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine that the number of erroneous bits in each of the first received response and the second received response is greater than a threshold number of bits compared to respective expected bit sequences of a first ATQ(x) response and a second ATQ(x) response to the first REQ(x) and the second REQ(x).

[0028] In one or more embodiments, the poller being arranged to transmit the multiple requests includes the poller being arranged to transmit a third REQ(x) after the second REQ(x), and wherein the poller being arranged to count the number of bits includes the poller being arranged to determine the number of bits including determining that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is greater than the threshold number of bits; and wherein the poller being arranged to perform the wireless charging includes the poller being arranged not to stop the charging.

[0029] In one or more embodiments, the poller being arranged to transmit the multiple requests includes the poller being arranged to transmit a third REQ(x) after the second REQ(x); wherein the poller being arranged to count the number of bits includes the poller being arranged to determine that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is less than the threshold number of bits, and wherein the poller being arranged to perform the wireless charging includes the poller being arranged to stop the wireless charging.

[0030] In one or more embodiments, the poller being arranged to transmit the plurality of requests includes the poller being arranged to transmit a third REQ(x) after the second REQ(x); wherein the poller being arranged to count the number of bits includes the poller being arranged to determine that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and to determine the position of the bits in the third received response that are erroneous compared to the expected bit sequence of the ATQ(x) response to the third REQ(x); wherein the poller being arranged to perform the wireless charging includes the poller being arranged to stop the wireless charging based on the position of the bits in the third received response being the same as the position of the bits in the first received response to the first REQ(x) that are erroneous compared to the expected bit sequence of the ATQ(x) response to the first REQ(x).

[0031] In one or more embodiments, the poller being arranged to perform the wireless charging includes the poller being arranged to one of reduce wireless charging power and stop the wireless charging, wherein the wireless charging is based on the Wireless Charging Technical Specification Version 2.0 defined by the NFC Forum.

[0032] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An example near field communication (NFC) wireless charging system is shown in accordance with an embodiment.

[0034] Figure 2 is an example flow diagram of functionality associated with polling for foreign object detection, according to an embodiment.

[0035] The purpose of the drawings is to illustrate example embodiments, but it is to be understood that the embodiments are not limited to the arrangements and instrumentality shown in the drawings. DETAILED DESCRIPTION

[0036] The detailed description of the accompanying drawings is intended to describe various embodiments of the present disclosure, and is not intended to represent the only form in which the present disclosure can be practiced. It should be understood that the same or equivalent functions can be achieved by different embodiments intended to be included in the spirit and scope of the present disclosure.

[0037] NFC wireless charging systems that also perform near field communication (NFC) communication are typically arranged to detect the presence of a foreign object, such as a near field communication (NFC) card, before or during wireless charging, and stop wireless charging based on this detection. However, sometimes the wireless charging system falsely detects an NFC card and stops wireless charging. For example, a poller of the wireless charging system may detect interference from another poller or listener in the wireless charging system as the presence of an NFC card and stop wireless charging. The false detection results in a reduction in the charging efficiency of the wireless device being charged by the wireless charging system.

[0038] Embodiments disclosed herein relate to a poller in an NFC wireless charging system that distinguishes interference from another poller or a listener in the wireless charging system from the presence of a foreign object such as an NFC card that may cause wireless charging to stop. Interference from a poller or a listener should not have a substantial impact on wireless charging compared to the presence of a foreign object such as an NFC card that may affect wireless charging. The poller uses multiple polling commands to detect the presence of an NFC card or interference from the poller or the listener, and based on the response (or lack of response) to the polling command, the NFC wireless charging system is able to distinguish interference from the poller or the listener from the presence of an NFC card. If the interference comes from the poller or the listener, wireless charging is not stopped so that charging efficiency is not reduced, and if an NFC card is detected, wireless charging is stopped or the wireless charging power is reduced. In order not to confuse the description, well-known instructions, protocols, structures, and techniques are not shown in detail.

[0039] Figure 1An example wireless charging system 100 is shown according to an embodiment. In an example, the wireless charging system 100 may be based on the wireless charging technical specification version 2.0 defined by the NFC Forum. In an example, the wireless charging system 100 may be used to charge the battery of a device such as an earbud, a wireless device, or a virtual reality glasses. The system 100 may have multiple pollers 102 and listeners 104, and the system 100 is shown in this example as having two pollers 102-1, 102-2 and two listeners 104-1, 104-2 and being a dual poller system. The poller may be a wireless charging transmitter that generates an electromagnetic signal, and the listener may be a wireless charging receiver that receives the electromagnetic signal. The poller and the listener may have corresponding antennas 106, 108. In addition, the poller may be coupled to a power source 110 to power the poller, and the listener may also be coupled to a corresponding battery 112. For example, the listener 104-1 may be coupled to the battery 112-1, and the listener 104-2 may be coupled to the battery 112-2. A corresponding device circuit system 114, such as a circuit system for earbuds, a wireless device, or virtual reality glasses, may also be coupled to and powered by a corresponding battery 112. For example, device circuit system 114-1 may be coupled to battery 112-1, and device circuit system 114-2 may be coupled to battery 112-2. Controller 124 may be a processing circuit system for performing functions associated with wireless charging. Additionally, listener 104-1, battery 112-1, and device circuit system 114-1 may define a wireless device, and listener 104-2, battery 112-2, and device circuit system 114-2 may define another wireless device. In an example, system 100 and its components may be implemented by one or more of analog circuit systems, mixed signal circuit systems, memory circuit systems, logic circuit systems, and processing circuit systems that execute code that performs the disclosed functions when executed by the processing circuit system, as well as other embodiments. Additionally, as described herein, references to the poller 102, antenna 106, antenna 108, battery 112, and device circuitry 114, without specific identification by a "-1" or "-2" designation, may refer to one or more instances of the respective poller, antenna, battery, and device circuitry, depending on the context, and are not limited to references to only the singular or the plural.

[0040] The poller 102-1 may generate an electromagnetic signal that is transmitted by the antenna 106-1 of the poller 102-1 and received by the antenna 108-1 of the listener 104-1. Similarly, the poller 102-2 may generate an electromagnetic signal that is transmitted by the antenna 106-2 of the poller 102-2 and received by the antenna 108-2 of the listener 104-2. The poller 102-1 and the listener 104-1 may be a charging pair for charging the battery 112-1, and the poller 102-2 and the listener 104-2 may be another charging pair for charging the battery 112-2. In this arrangement, the poller 102-1 is not typically used to perform wireless charging with the listener 104-2, and the poller 102-2 is not typically used to perform wireless charging with the listener 104-1.

[0041] In an example, the poller and the listener may exchange signals during the wireless charging process. For example, the poller 102-1 may transmit an analog ping to the listener to detect the presence of a wireless device to be charged. The analog ping may be generated by a modulation process. The poller 102-1 may have a drive circuit and a resonant circuit. In an example, the drive circuit in the poller 102-1 may signal the resonant circuit in the poller 102-1 to generate an electromagnetic signal with a predetermined magnitude and phase indicating the transmitted analog ping. The resonant circuit may transmit an electromagnetic signal via the antenna 106-1 of the poller 102-1. The presence of the listener 104-1 may cause the resonant circuit of the listener 104-1 to induce an electromagnetic signal, which is detected in the poller 102-1. The predetermined phase and magnitude of the induced electromagnetic signal in the poller 102-1 may indicate the presence of a wireless device for charging. The poller 102-1 may also communicate with the listener 104-1. The poller 102-1 may transmit an electromagnetic signal, such as a digital ping, which induces an electromagnetic signal in a resonant circuit in the listener 104-1. The listener 104-1 may detect the induced electromagnetic signal and send a response to the digital ping, such as a signal strength data packet or a request to adjust the charging power. The drive circuit of the listener 104-1 may generate an electromagnetic signal in the resonant circuit of the listener 104-1 indicating a response to be transmitted, which induces an electromagnetic signal in the poller 102-1. The induced electromagnetic signal is detected by the poller 102-1, thereby causing the response to be transmitted from the listener 104-1 to the poller 102-1.

[0042] In addition to performing wireless charging, the wireless charging system 100 may also be arranged to communicate with a near field communication (NFC) card. Thus, the NFC card 116 may approach the system 100 and store data in an NFC tag of the NFC card 116. The poller 102 of the system 100 may communicate with the NFC card 116 to read the data in the NFC tag. In an example, the communication may start from the poller 102-1 detecting the presence of the NFC card 116. In an example, the poller 102-1 may send a request referred to as REQ(x)120 to the NFC card 116 to detect the presence of the NFC card 116. REQ(x) may be a multi-bit message sent from the poller 102-1. Then, the NFC card 116 approaching the poller 102-1 may receive the request and send a response to indicate its presence. The response may be a multi-byte sequence referred to as ATQ(x)122. The REQ(x) 120 and ATQ(x) 122 sent between the poller 102-1 and the NFC card 116 may be defined by International Standards Organization / International Electrotechnical Commission (ISO / IEC) 14443-3, ISO / IEC 1444-3 (Identification Card-Contactless Integrated Circuit Card), where "x" corresponds to a request and response to a Type A NFC card, a Type B NFC card, or a Type C NFC card. REQ(x) is generally a request command sent by the poller to detect an NFC card in an operating field, and ATQ(x) is a response to the request transmitted by all NFC cards in an idle state after the REQ command. Based on the poller 102-1 determining that the NFC card 116 is close to the wireless charging system 100, the NFC card 116 may transmit data in the NFC tag to the poller 102-1.

[0043] Unlike the power requirements for data exchange between a listener or NFC card 116, wireless charging requires the use of high-power electromagnetic signals. The presence of an NFC card during NFC wireless charging performed by the NFC wireless charging system 100 poses a fire risk or overheating risk to the NFC card or the system 100. In order to reduce this risk, the system 100 may perform a foreign object check during the wireless charging process. Foreign object check may be a process of detecting whether a foreign object is present before or during wireless charging, and in an example, the NFC card 116 present before or during wireless charging is referred to herein as a foreign object. Simulated pinging to detect the presence of a wireless device may also facilitate the performance of simulated foreign object detection. The driver circuit may cause the resonant circuit of the poller 102-1 to generate an electromagnetic signal having a first magnitude and a first phase, which is transmitted by the antenna 106-1. If there is no NFC card 116 or interference, the electromagnetic signal in the resonant circuit of the poller 102-1 may be substantially the first magnitude and the first phase. If there is an NFC card 116 or interference from a poller or a listener, the NFC card 116 or the interference from the poller or the listener may have a measurable effect on the first magnitude and the first phase of the electromagnetic signal in the resonant circuit so that the electromagnetic signal is a second magnitude and a second phase due to electromagnetic coupling. If the change in magnitude and phase between the first magnitude and the second magnitude and the first phase and the second phase exceeds a predetermined range, a foreign object may be present, and wireless charging may be stopped or the power associated with wireless charging may be reduced to prevent damage to the NFC card 116 or the system 100. In addition, a foreign object indicator 118, such as a light on the system 100, may be activated to indicate the presence of a foreign object. However, if the measured magnitude and phase do not exceed the predetermined range, there may be no foreign object in the form of an NFC card 116, wireless charging may not be stopped, and the foreign object indicator 118 is not activated.

[0044] The two pollers 102-1, 102-2 and the two listeners 104-1, 104-2 of the system 100 may be collocated. In an example, the poller 102-2 may generate interference 121 to the poller 102-1 due to the communication between the poller 102-2 and the listener 104-2. In another example, the two pollers 102-1, 102-2 and the two listeners 104-1, 104-2 of the system 100 may be collocated, and the listener 104-2 may generate interference 123 to the poller 102-1 based on the listener 104-2 responding to the communication from the poller 102-2. The interference, which is an electromagnetic signal, may couple with the resonant circuit of the poller 102-1 and cause a foreign object to be detected based on a simulated foreign object detection process, even if there is no foreign object in fact. Wireless charging may be terminated or reduced in power, thereby affecting charging efficiency. In an example, the poller 102 - 1 may signal the charging controller 124 to terminate or reduce the wireless charging power.

[0045] Embodiments disclosed herein relate to a poller 102-1 that digitally distinguishes interference from another poller 102-2 or a listener 104-2 from the presence of a foreign object, such as an NFC card 116, before or during wireless charging, which would typically cause wireless charging to stop or reduce charging power. Interference from a poller 102-2 or a listener 104-2 is not considered a foreign object and should not affect wireless charging. The detection begins with the poller 102-1 performing an analog foreign detection process. Based on the possible detection of a foreign object, the poller 102-1 then performs a digital foreign detection process to confirm whether the foreign object is close to the poller 102-1 or whether the interference is caused by the listener 104-2 or the poller 102-2. Message transmission based on REQ(x) and ATQ(x) allows interference from foreign objects, such as an NFC card 116, to be distinguished from interference from a poller or a listener. If the messaging indicates that a foreign object is present, the poller 102-1 may stop wireless charging or reduce the charging power provided to the listener 104-1. In addition, the foreign object indicator 118 may be illuminated when a foreign object is detected and not illuminated when a foreign object is not detected. If the messaging indicates that a foreign object is not present and the interference is caused by the poller or the listener, the poller 102-1 will not stop charging or reduce the wireless charging power. The indicator 118 is also not illuminated.

[0046] Figure 2200 is an example flow chart of functions associated with polling for foreign object detection according to an embodiment. The polling may be based on sending one or more requests, i.e., REQ(x), by the poller and based on the sending of the requests, determining the presence or absence of foreign objects or interference from the poller or listener based on one or more responses ATQ(x). In an example, the NFC card 116 is in the form of a Type A NFC card, the REQ(x) sent may be REQ(A), and the ATQ(x) received may be ATQ(A). In another example, the NFC card 116 is in the form of a Type B NFC card, the REQ(x) sent may be REQ(B), and the ATQ(x) received may be ATQ(B). In yet another example, the NFC card 116 is in the form of a Type C NFC card, the REQ(x) sent may be REQ(C), and the ATQ(x) received may be ATQ(C). The functions of flowchart 200 may be performed by controller 124 one or more times before or during NFC wireless charging (e.g., in a background process) with different REQ(x) and corresponding ATQ(x) to detect the presence of three types of NFC cards. Other variations of the execution of the functions are also possible.

[0047] At 202, the poller performs simulated foreign object detection, which detects the possible presence of a foreign object. In an example, a foreign object may be detected based on the poller measuring a change in magnitude and phase of an electromagnetic signal in a resonant circuit of the poller exceeding a predefined range from an electromagnetic signal generated by a driver circuit of the poller. The simulated foreign object detection may not be able to distinguish the presence of an NFC card as a foreign object and a possible fire or safety risk from interference from a poller or a listener that is not a foreign object. At 204, the poller sends a pause message to the listener to put the listener in a pause state to determine whether the possible foreign object is an actual foreign object or interference from another poller or listener in the system 100. For example, the poller 102-1 may send a pause message to the corresponding listener 104-1. The pause message may be a bit sequence indicating that the listener 104-1 does not respond to a REQ(x) from the poller 102-1 (compared to an idle state in which the listener 104-1 can respond to the REQ(x)). At 206, the poller may send a request for communication, such as REQ(x). "x" may be one of a Type A, Type B, or Type C NFC request. At 208, the result of the request is determined. "x" may indicate one of a Type A NFC, a Type B NFC, or a Type C NFC associated with the communication, such that if REQ(A) is sent, ATQ(A) may be received, if REQ(B) is sent, ATQ(B) may be received, and if REQ(C) is sent, ATQ(C) may be received for the remaining steps in the flowchart 200. In an example, ATQ(x) may be an expected two-byte bit sequence defined by the NFC standard, but other sizes may be used. If the response to the request received by the poller is the expected bit sequence of ATQ(x), then a foreign object in the form of an NFC card is detected at 210. If a response to the request is not received within a predefined time, the response times out, and no foreign object in the form of an NFC card 116 is detected at 212. No response may be that the poller did not receive a bit in response to the request. Since no foreign object is detected, wireless charging is not stopped. If one or more bits received in response to the request are not the expected bit sequence of ATQ(x), then at 214, the number of bits in the received bits that are erroneous compared to the expected bit sequence of ATQ(x) is determined. Due to one or more of integrity errors, framing errors, protocol errors, or collision errors, not all bits of the expected bit sequence of ATQ(x) may be received correctly. For example, if the one or more bits received are "0010 0011 0111 1111" and the expected bit sequence of ATQ(x) is "1101 0001 00001011", there may be nine erroneous bits or more than one byte of erroneous bits. If one byte or less of bits are erroneous, then a foreign object is present at 210.Assuming that interference from a poller or listener cannot simulate the entire byte of ATQ(x), the presence of at least one byte of the expected bit sequence of ATQ(x) in the received bits indicates the presence of a foreign object in the form of NFC card 116. If the received one or more bits include more than one byte of erroneous bits, the positions of those received bits that are erroneous based on the expected bit sequence of ATQ(x) are recorded at 216. In an example, the underlined bits in "0010 0011 0111 1111" may indicate the positions of the received bits that are erroneous compared to the expected bit sequence of ATQ(x) "1101 0001 0000 1011". In an example, the received bits that are not in the expected bit sequence of the ATQ(x) response may indicate a collision between responses from two NFC cards responding to the request, interference from a poller or listener that may respond to the request or transmit an interfering signal, or interference from a poller or listener and one or more NFC cards. At 216 , the wireless charger has determined the presence of an NFC card or interference by a poller or listener.

[0048] At 218, the poller may send a second request, i.e., REQ(x). The second request may be another request to detect the presence of an NFC card. At 220, the result of the request is determined. If the received bits are the expected bit sequence of the received ATQ(x), then at 210, a foreign object in the form of an NFC card introduced after the processing in the above steps is detected. The NFC standard may specify that if an NFC card has already responded to a request, the NFC card will not respond to another consecutive request and will only respond to an alternative request. If no response is received, there may be multiple NFC cards - which do not provide a response to the request according to the NFC standard, or the poller or listener generating interference now stops at 222. If one or more bits that are erroneous compared to the expected bit sequence of ATQ(x) are received, then at step 224, it is determined that there may be interference from the poller or listener or interference from the poller or listener and an NFC card introduced after step 208, and the process continues to step 226.

[0049] In some examples, a determination may be made between step 224 and step 226 (not shown) as to whether the number of bits in the received bits that are in error compared to the expected bit sequence of ATQ(x) is less than or equal to one byte. If one byte or less is in error, then an NFC card is present and the process moves to step 210. If not one byte or less is in error, then an NFC card is not present and the process moves to step 226.

[0050] At 226, the poller may send a third request, namely REQ(x). The third request may be a request to detect the presence of an NFC card. At 228, the result of the request is determined. If the one or more bits received are the expected bit sequence of ATQ(x), then at 206, a foreign object in the form of an NFC card is detected. In this case, if the other NFC cards are removed, there is only one NFC, and the NFC card that did not respond to the request in step 208 now responds, then the NFC card can be detected. If no response is received, then at 212, there is no NFC card because the NFC card will respond to the third request. If the one or more bits received in response to the request are not the expected bit sequence of ATQ(x), then at 230, the number of bits in the received bits that are erroneous compared to the expected bit sequence of ATQ(x) is determined. If the error in the received bits is one byte bit or less, then at 208, there is an NFC card. If the error in the received bits is greater than one byte of bits, then at 232, determine the positions of those bits received that are erroneous compared to the expected bit sequence of ATQ(x) and whether the positions are the same as the positions recorded at 216. If the positions are the same as the positions recorded at 216, then there is an NFC card at 210, because this means that the NFC card that responded previously responds again with the same timing. For example, if the position of the erroneous bits is "00100011 0111 1111", which is the same position at 216, then there is an NFC card. Assume that two NFC cards cause the same conflict in response to the request. Stop wireless charging. If the positions are not the same, then there is no NFC card at 212, and the interference is generated by the poller or listener. Do not stop wireless charging. In the example, if an NFC card is detected, an indication can be provided to the charging controller 124 to disable wireless charging or reduce the charging power in the wireless system 100, and if an NFC card is not detected, wireless charging may not be affected and wireless charging efficiency is maintained.

[0051] The embodiment described above describes that ATQ(x) is two bytes, and when the poller receives at least one byte of the expected bit sequence of ATQ(x), there is an NFC card. If less than one byte of the two bytes of the expected bit sequence of ATQ(x) is received, it is determined whether there is an NFC card or interference from a poller or a listener. The number of bytes or bits used to determine the presence of an NFC card or the presence of interference from a poller or a listener may not be limited to the described embodiment, and may generally be considered as a threshold bit number. For example, less than one byte or more than one byte of the expected bit sequence of the received ATQ(x) may indicate the presence of an NFC card. In addition, in addition to REQ(x) and ATQ(x), request and response messaging with a size less than or greater than two bytes of the expected bit sequence may be used to determine the presence of an NFC card.

[0052] In addition, in an embodiment, the listener may determine whether the received plurality of bits are not erroneous or erroneous to determine whether wireless charging is to be performed. The threshold number of bits for determining whether there is foreign object interference or interference by the poller or listener may be adjusted to correspond to the determination.

[0053] In an embodiment, a method for wireless charging by a wireless charging system is disclosed. The method includes: pausing a listener to respond to multiple requests communicated with a poller, wherein the poller and the listener of the system form a wireless charging pair; transmitting the multiple requests by the poller in response to pausing the communication with the listener; receiving at least one corresponding response to the multiple requests; counting the number of bits in the received response that are erroneous compared to an expected bit sequence of a response to the transmitted request, wherein the count is greater than one; determining whether a near field communication (NFC) card is proximate to a wireless charger based on the count of the number of bits; and performing the wireless charging of the system based on the determination. In an example, transmitting the multiple requests includes transmitting a first REQ(x) defined by the International Organization for Standardization / International Electrotechnical Commission (ISO / IEC) 14443-3 NFC standard; wherein counting the number of bits includes determining the number of bits in the first received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard. In an example, the method further includes recording the position of the bit in error in the expected bit sequence of the ATQ(x) response to the first REQ(x). In an example, transmitting the plurality of requests includes transmitting a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein counting the number of bits includes determining that the number of bits in error compared to the expected bit sequence of the ATQ(x) response to the first REQ(x) defined by the NFC standard is greater than a threshold number of bits in the first received response, and wherein performing the wireless charging includes stopping the wireless charging. In an example, "x" indicates a request and response corresponding to one of a Type A NFC card, a Type B NFC card, or a Type C NFC card defined by the ISO / IEC 14443-3 NFC standard. In an example, transmitting the plurality of requests comprises transmitting a first REQ(x) followed by a second REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein counting the number of bits comprises determining that the number of bits in each of the first received response and the second received response that are in error compared to respective expected bit sequences of a first ATQ(x) response and a second ATQ(x) response to the first REQ(x) and the second REQ(x) is greater than a threshold number of bits. In an example, transmitting the plurality of requests comprises transmitting a third REQ(x) after the second REQ(x), and wherein counting the number of bits comprises determining that the number of bits in the third received response that are in error compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and wherein performing the wireless charging comprises not stopping the charging.In an example, transmitting the plurality of requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of erroneous bits in the third received response compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is less than the threshold number of bits, and wherein performing the wireless charging includes stopping the wireless charging. In an example, transmitting the plurality of requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of bits in the third received response that are in error compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and determining the position of the bits in the third received response that are in error compared to the expected bit sequence of the ATQ(x) response to the third REQ(x), wherein adjusting the wireless charging includes stopping the wireless charging based on the position of the bits in error in the third received response being the same as the position of the bits in error in the first received response to the first REQ(x) compared to the expected bit sequence of the ATQ(x) response to the first REQ(x). In an example, performing the wireless charging includes reducing wireless charging power or stopping the wireless charging, wherein the wireless charging is based on the Wireless Charging Technical Specification Version 2.0 defined by the NFC Forum.

[0054] In another embodiment, a wireless charging system is disclosed. The system includes: a poller; a listener, wherein the listener and the poller form a wireless charging pair; wherein the poller is arranged to: suspend the listener to respond to multiple requests communicated with the poller, wherein the poller and the listener of the system form a wireless charging pair; transmit the multiple requests by the poller in response to suspending the communication with the listener; receive at least one corresponding response to the multiple requests; compare the bits of the received response with the expected bit sequence of the response to the transmitted request; count the number of bits in the received response that are erroneous compared to the expected bit sequence of the response to the transmitted request, wherein the count is greater than one; determine whether an NFC card is close to a wireless charger based on the count of the number of bits; and perform the wireless charging of the system based on the determination. In an example, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine the number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard. In an example, the system further comprises recording the position of the bit in error in the expected bit sequence of the ATQ(x) response to the first REQ(x). In an example, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein the poller being arranged to count a number of bits comprises the poller being arranged to determine that the number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard is less than a threshold number of bits, and wherein the poller being arranged to perform the wireless charging comprises the poller being arranged to stop the wireless charging. In an example, "x" indicates a request and response corresponding to one of a Type A NFC card, a Type B NFC card, or a Type C NFC card defined by the ISO / IEC 14443-3 NFC standard. In an example, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a first REQ(x) followed by a second REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine that a number of bits in error in each of the first received response and the second received response is greater than a threshold number of bits compared to respective expected bit sequences of a first ATQ(x) response and a second ATQ(x) response to the first REQ(x) and the second REQ(x).In an example, the poller being arranged to transmit the plurality of requests includes the poller being arranged to transmit a third REQ(x) after the second REQ(x), and wherein the poller being arranged to count the number of bits includes the poller being arranged to determine the number of bits includes determining that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits; and wherein the poller being arranged to perform the wireless charging includes the poller being arranged not to stop the charging. In an example, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a third REQ(x) after the second REQ(x); wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is less than the threshold number of bits, and wherein the poller being arranged to perform the wireless charging comprises the poller being arranged to stop the wireless charging. In an example, the poller being arranged to transmit the plurality of requests comprises the poller being arranged to transmit a third REQ(x) after the second REQ(x); wherein the poller being arranged to count the number of bits comprises the poller being arranged to determine that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and to determine the positions of the bits in the third received response that are erroneous compared to the expected bit sequence of the ATQ(x) response to the third REQ(x); wherein the poller being arranged to perform the wireless charging comprises the poller being arranged to stop the wireless charging based on the position of the bits in the third received response being the same as the position of the bits in the first received response to the first REQ(x) that are erroneous compared to the expected bit sequence of the ATQ(x) response to the first REQ(x). In an example, the poller being arranged to perform the wireless charging includes the poller being arranged to one of reduce wireless charging power and stop the wireless charging, wherein the wireless charging is based on the Wireless Charging Technical Specification Version 2.0 defined by the NFC Forum.

[0055] Several embodiments have been described in detail above, and various modifications are possible. The disclosed subject matter including the functional operations described in this specification can be implemented in electronic circuits, computer hardware, firmware, software, or a combination thereof, such as in the structural components disclosed in this specification and their structural equivalents: may include a program (e.g., a program encoded in a non-transitory computer-readable medium, which can be a memory device, a storage device, a machine-readable storage substrate or other physical, machine-readable medium, or a combination of one or more of them) to cause one or more data processing devices such as a processor to perform the described operations.

[0056] Although this specification contains many details, these should not be interpreted as limitations on the scope of protection that can be claimed, but rather as descriptions of features that can be specific to a particular embodiment. Certain features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination. In addition, although features may be described above as working in certain combinations and even initially claimed, in some cases, one or more features from the claimed combination may be deleted from the combination, and the claimed combination may be directed to sub-combinations or variations of sub-combinations.

[0057] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all of the operations shown be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments.

[0058] Unless specifically stated otherwise, use of the phrase "at least one of" after a list with the conjunction "and" should not be viewed as an exclusive list, and should not be understood as a category list with one item from each category. A sentence stating "at least one of A, B, and C" can contain only one of the listed items, multiple of the listed items, and one or more of the items in the list and another item not listed.

[0059] Other implementations are within the scope of the following claims.

Claims

1. A method for wireless charging by a wireless charging system, characterized in that: The method comprises: pausing a listener to respond to a plurality of requests to communicate with a poller, wherein the poller and the listener of the system form a wireless charging pair; transmitting, by the poller, the plurality of requests in response to pausing the communication with the listener; receiving at least one corresponding response to the plurality of requests; counting a number of bits in the received response that are in error compared to an expected bit sequence for a response to the transmitted request, wherein the count is greater than one; determining whether a near field communication (NFC) card is close to a wireless charger based on the count of the number of bits; and The wireless charging of the system is performed based on the determination.

2. The method according to claim 1, characterized in that Transmitting the plurality of requests comprises transmitting a first REQ(x) defined by an International Organization for Standardization / International Electrotechnical Commission (ISO / IEC) 14443-3 NFC standard; wherein counting the number of bits comprises determining a number of bits in a first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard.

3. The method according to claim 2, characterized in that Also included is recording the position of the bit that is erroneous in the expected bit sequence of the ATQ(x) response to the first REQ(x).

4. The method according to claim 1, characterized in that: Transmitting the plurality of requests comprises transmitting a first REQ(x) defined by the ISO / IEC 14443-3 NFC standard; wherein counting the number of bits comprises determining that the number of bits in the first received response that are in error compared to an expected bit sequence of an ATQ(x) response to the first REQ(x) defined by the NFC standard is greater than a threshold number of bits, and wherein performing the wireless charging comprises stopping the wireless charging.

5. The method according to claim 4, characterized in that “x” indicates a request and a response corresponding to one of a type A NFC card, a type B NFC card, or a type C NFC card defined by the ISO / IEC 14443-3 NFC standard.

6. The method according to claim 1, characterized in that Transmitting the plurality of requests comprises transmitting a first REQ(x) followed by a second REQ(x) defined by the ISO14443-3 NFC standard; wherein counting the number of bits comprises determining that a number of erroneous bits in each of a first received response and a second received response is greater than a threshold number of bits compared to respective expected bit sequences of a first ATQ(x) response and a second ATQ(x) response to the first REQ(x) and the second REQ(x).

7. The method according to claim 6, characterized in that Transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x), and wherein counting the number of bits includes determining that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and wherein performing the wireless charging includes not stopping the charging.

8. The method according to claim 6, characterized in that Transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of erroneous bits in the third received response compared to the expected bit sequence of the ATQ(x) response to the third REQ(x) is less than the threshold number of bits, and wherein performing the wireless charging includes stopping the wireless charging.

9. The method according to claim 6, characterized in that Transmitting the multiple requests includes transmitting a third REQ(x) after the second REQ(x); wherein counting the number of bits includes determining that the number of bits in the third received response that are erroneous compared to an expected bit sequence of an ATQ(x) response to the third REQ(x) is greater than the threshold number of bits, and determining the positions of the bits in the third received response that are erroneous compared to the expected bit sequence of the ATQ(x) response to the third REQ(x), wherein adjusting the wireless charging includes stopping the wireless charging based on the position of the bits in the third received response being the same as the position of the bits in the first received response to the first REQ(x) that are erroneous compared to the expected bit sequence of the ATQ(x) response to the first REQ(x).

10. A wireless charging system, characterized in that: include: Poller; a listener, wherein the listener and the poller form a wireless charging pair; The poller is arranged to: suspend the listener from responding to multiple requests communicated with the poller, wherein the poller and the listener of the system form a wireless charging pair; transmit the multiple requests by the poller in response to suspending the communication with the listener; receive at least one corresponding response to the multiple requests; compare the bits of the received response with the expected bit sequence of the response to the transmitted request; count the number of bits in the received response that are erroneous compared to the expected bit sequence of the response to the transmitted request, wherein the count is greater than one; determine whether an NFC card is close to a wireless charger based on the count of the number of bits; and perform the wireless charging of the system based on the determination.

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