Wireless power transmission circuit and method capable of detecting wireless power receiver and foreign matter

Abstract

The invention relates to a wireless power transmission circuit and method capable of detecting a wireless power receiver and a foreign matter. The wireless power transmitting circuit includes: a reflux circuit including a plurality of switches coupled to the resonant transmitting circuit; and an emission control circuit for generating a pulse width modulation control signal to control the plurality of switches in a power supply program to generate a wireless emission power supply in the resonant emission circuit to wirelessly supply power to the wireless power receiving circuit, and for controlling the plurality of switches to generate a wireless test power supply in the resonant emission circuit based on the operation frequency in an exploration program. The exploration procedure includes: measuring a peak value of a transmission signal corresponding to the wireless test power supply; judging whether foreign matters exist or not according to the peak value of the transmitted signal; and / or judging whether a wireless power receiving circuit exists or not according to the peak value of the transmitted signal, and performing a power supply program when judging that the wireless power receiving circuit exists.

Description

Technical Field

[0001] The present invention relates to a wireless power transmission circuit, and more particularly to a wireless power transmission circuit capable of detecting a wireless power receiver and foreign objects. The present invention also relates to a method for detecting a wireless power receiver and foreign objects. Background Art

[0002] See also Figure 1 , Figure 1 A circuit diagram and waveforms of a foreign object detection sensor in a wireless power transmission system of the prior art are shown. Figure 1 The conventional foreign object detection sensor shown includes a detection coil 101 and a capacitor 102, which form a resonant tank circuit. The resonant tank circuit is charged by an external power source. After the external power source is removed, the energy stored in the resonant tank circuit will oscillate between the detection coil 101 and the capacitor 102. Since the electrical energy will be dissipated in the detection coil, the capacitor and any other parasitic elements (such as printed circuit board traces or wires), Figure 1 As shown in the right half of the figure, the electrical energy decays over time, which can be used to determine and identify whether there is a receiver or foreign object approaching. Figure 1 A disadvantage of the prior art shown is that an additional detection coil circuit is required.

[0003] Figure 2 A schematic diagram showing a prior art transmit resonant waveform on a wireless power transmitter with a wireless power receiver. Figure 2 The known wireless power transmission system shown determines and identifies whether there is a receiver or foreign object approaching by measuring the natural response attenuation rate of the transmitted signal.

[0004] In view of the above shortcomings of the prior art, the present invention proposes a wireless power transmission circuit that does not require an additional detection coil circuit. Summary of the invention

[0005] In one aspect, the present invention provides a wireless power transmission circuit, which includes: a reverse current circuit, including a plurality of switches, coupled to a resonant transmission circuit, wherein the resonant transmission circuit includes a transmitting coil and a resonant capacitor coupled to each other; and a transmission control circuit, which is used to generate a pulse width modulation control signal in a power supply procedure S700 to control the plurality of switches to generate a wireless transmission power in the resonant transmission circuit to wirelessly supply power to a corresponding wireless power receiving circuit, and the transmission control circuit is used to control the plurality of switches in a groping procedure to generate a wireless test power in the resonant transmission circuit based on an operating frequency, and the transmission control circuit is used to generate a wireless test power based on an operating frequency in the resonant transmission circuit. Determine whether there is a foreign object and / or whether the wireless power receiving circuit exists according to a transmission signal, wherein the transmission signal is related to a cross-voltage of the transmitting coil; wherein the operating frequency and an intrinsic resonant frequency of the resonant transmitting circuit have an offset frequency that is not zero; wherein the exploration program includes the following steps: S100: measuring the peak value of the transmission signal corresponding to the wireless test power supply; wherein the exploration program also includes: S250: determining whether the foreign object exists according to the peak value of the transmission signal; and / or S350: determining whether the wireless power receiving circuit exists according to the peak value of the transmission signal, wherein when it is determined that the wireless power receiving circuit exists, the power supply program S700 is performed.

[0006] In another aspect, the present invention provides a method for detecting a wireless power receiver and a foreign object, comprising: in a power supply procedure S700, controlling a resonant transmitting circuit to generate a wireless transmitting power to wirelessly supply power to a corresponding wireless power receiving circuit; and in a groping procedure, controlling the resonant transmitting circuit to generate a wireless test power based on an operating frequency, and judging whether there is a foreign object and / or whether the wireless power receiving circuit exists according to a transmission signal of the resonant transmitting circuit, wherein the operating frequency and an intrinsic resonant frequency of the resonant transmitting circuit have an offset frequency that is not zero; wherein the groping procedure comprises the following steps: S100: measuring the peak value of the transmission signal corresponding to the wireless test power; wherein the groping procedure further comprises: S250: judging whether there is the foreign object according to the peak value of the transmission signal; and / or S350: judging whether there is the wireless power receiving circuit according to the peak value of the transmission signal, wherein when it is judged that the wireless power receiving circuit exists, the power supply procedure S700 is performed.

[0007] In one embodiment, the step S250 includes: S200: judging whether the foreign object exists according to whether the peak value of the transmitted signal exceeds a foreign object peak threshold; and / or S300: judging whether the foreign object exists according to whether the peak-frequency change rate of the operating frequency corresponding to the peak value of the transmitted signal exceeds a foreign object change rate threshold.

[0008] In one embodiment, the step S350 includes: S500: determining whether the wireless power receiving circuit exists according to whether the peak value of the transmitted signal exceeds a receiving peak value threshold; and / or S600: determining whether the wireless power receiving circuit exists according to whether the peak-frequency change rate of the peak value of the transmitted signal corresponding to the operating frequency exceeds a receiving change rate threshold.

[0009] In one embodiment, when the foreign object is present, the resonant transmitting circuit has a first response resonant frequency, wherein when the wireless power receiving circuit is present, the resonant transmitting circuit has a second response resonant frequency, wherein the first response resonant frequency and the second response resonant frequency are respectively located on different sides of the intrinsic resonant frequency.

[0010] In one embodiment, the first response resonance frequency is higher than the intrinsic resonance frequency, and the intrinsic resonance frequency is higher than the second response resonance frequency.

[0011] In one embodiment, step S200 includes determining whether the foreign object exists based on whether the peak value of the transmitted signal is greater than the foreign object peak threshold, wherein step S500 includes determining whether the wireless power receiving circuit exists based on whether the peak value of the transmitted signal is less than the receiving peak threshold, wherein the receiving peak threshold is less than the foreign object peak threshold.

[0012] In one embodiment, step S300 includes determining whether the foreign object exists based on whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is greater than the absolute value of the foreign object change rate threshold, and step S600 includes determining whether the wireless power receiving circuit exists based on whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is less than the absolute value of the receiving change rate threshold, wherein the absolute value of the receiving change rate threshold is less than the absolute value of the foreign object change rate threshold.

[0013] In one embodiment, the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is obtained by dividing the difference between a first transmitting signal peak value and a second transmitting signal peak value corresponding to a first operating frequency and a second operating frequency respectively by the difference between the first operating frequency and the second operating frequency.

[0014] In one embodiment, the first operating frequency is the same as the operating frequency, so that the peak value of the first transmitting signal can be used as the peak value of the transmitting signal.

[0015] In one embodiment, when it is determined in step S250 that the foreign object exists, the process returns to step S100 .

[0016] In one embodiment, the exploration procedure also includes a foreign object operation step S400, wherein when it is determined in the step S250 that the foreign object exists, the foreign object operation step S400 is performed and then the process returns to the step S100, wherein the foreign object operation step S400 includes: adding a delay time, and / or reducing the power level of the wireless test power supply.

[0017] In one embodiment, when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, the process returns to step S100 .

[0018] In one embodiment, the exploration procedure also includes step S900, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S900 is performed and then the process returns to step S100, wherein step S900 includes: increasing the power level of the wireless test power supply.

[0019] In one embodiment, the exploration procedure also includes step S800, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S800 is performed before entering step S100 or step S900, wherein step S800 includes: accumulating a cumulative number until the cumulative number exceeds a preset counting threshold before entering step S900, otherwise returning to step S100.

[0020] The advantage of the present invention is that the wireless power transmitting circuit of the present invention can utilize the simple circuit of the wireless power transmitting coil to detect foreign objects and the wireless power receiving circuit without the need for an additional detection coil circuit, and can only detect the stable peak value of low-power transmission without waking up the wireless receiving circuit, so it is easier to detect.

[0021] The following is a detailed description through specific embodiments to make it easier to understand the purpose, technical content, characteristics and effects achieved by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A circuit diagram and waveforms of a foreign object detection sensor in a wireless power transmission system of the prior art are shown.

[0023] Figure 2 A schematic diagram showing a prior art transmit resonant waveform on a wireless power transmitter with a wireless power receiver.

[0024] Figure 3 FIG. 4 is a circuit block diagram showing a wireless power transmission circuit according to an embodiment of the present invention.

[0025] Figure 4AFIG. 4 is a circuit block diagram showing a transmission control circuit in a wireless power transmission circuit according to an embodiment of the present invention.

[0026] Figure 4B FIG. 4 is a circuit block diagram showing a transmission control circuit in a wireless power transmission circuit according to another embodiment of the present invention.

[0027] Figure 5 is a schematic diagram showing a wireless power transmission circuit in several different situations according to an embodiment of the present invention.

[0028] Figure 6 FIG. 4 is a frequency response diagram showing a peak voltage across a transmitting coil of a wireless power transmitting circuit according to an embodiment of the present invention.

[0029] Figure 7 The waveform diagram of the transmission signal (transmitting coil voltage) measured when the wireless power transmission circuit transmits wireless test power in the exploration process according to an embodiment of the present invention.

[0030] Figure 8 It is a waveform diagram showing a transmission signal (transmitting coil voltage) measured when a wireless power transmitting circuit transmits wireless test power in an exploration procedure according to another embodiment of the present invention.

[0031] Fig. 9 and Fig. 10A is a frequency response diagram showing the peak voltage across the transmitting coil of the wireless power transmitting circuit according to an embodiment of the present invention.

[0032] Fig. 10B According to an embodiment of the present invention, Fig. 10A A partial enlarged view of .

[0033] Fig.11A FIG. 4 is a schematic diagram showing a determination interval of a peak voltage across a transmitting coil of a wireless power transmitting circuit according to an embodiment of the present invention.

[0034] Fig. 11B 4 is a schematic diagram showing a determination interval of a change rate of a voltage across a transmitting coil of a wireless power transmitting circuit relative to a frequency according to an embodiment of the present invention.

[0035] Figures 12A to 12J , Figure 13A-13B , Fig.14 and Fig.15 is a flowchart showing the steps of a discovery procedure for a wireless power transmitter circuit according to an embodiment of the present invention.

[0036] Explanation of symbols in the figure

[0037] 101: Detection Coil

[0038] 102: Capacitor

[0039] 20: Wireless power transmission circuit

[0040] 201: Reverse current circuit

[0041] 202: Transmission control circuit

[0042] 2021: Peak Detection Circuit

[0043] 2022: Analog-to-digital converters

[0044] 2023: Sub-control circuit

[0045] 2024: Peak calculation circuit

[0046] 203: Resonant Transmitter Circuit

[0047] 204: Voltage Divider

[0048] 30: Wireless power receiving circuit

[0049] 301: Resonant receiving circuit

[0050] 302: Rectifier

[0051] 303: Output control unit

[0052] 304: Load or battery

[0053] 40: Foreign matter

[0054] 50: Exploration Program

[0055] Cr: Resonance capacitor

[0056] Ct: Resonant capacitor

[0057] FO: Foreign object present

[0058] FO_slope_TH: Foreign matter change rate threshold

[0059] FO_vpp_fop, FO_vpp_fop1, FO_vpp_fop2, Null_vpp_fop, Null_vpp_fop1, Null_vpp_fop2: Transmitter coil cross-voltage peak value

[0060] FO_vpp_TH: Foreign object peak threshold

[0061] Fofs: offset frequency

[0062] Fop: operating frequency

[0063] Fop1: First operating frequency

[0064] Fop2: Second operating frequency

[0065] Fres_FO: First response resonant frequency

[0066] Fres_null: natural resonant frequency

[0067] Fres_RX: Second response resonant frequency

[0068] Lr: receiving coil

[0069] Lt: Transmitter coil

[0070] m1, m2, m3: Peak-frequency change rate

[0071] Nll: No electromagnetic induction body exists

[0072] RX: There is a wireless power receiving circuit

[0073] RX_slope_TH: Receive rate of change threshold

[0074] RX_vpp_fop, RX_vpp_fop1, RX_vpp_fop2: Peak voltage across the transmitting coil

[0075] RX_vpp_TH: Receive peak threshold

[0076] S100, S200, S250, S300, S350, S400, S500, S600, S700, S800, S900: Steps

[0077] Spk: peak voltage signal

[0078] Spkd: digital peak voltage signal

[0079] Spw: pulse width modulation control signal

[0080] SVL: Sense voltage signal

[0081] SVLd: Digital sense voltage signal

[0082] Top: Operation Cycle

[0083] Top1: First operation cycle

[0084] Top2: Second operation cycle

[0085] VI: DC Power Supply

[0086] VL: (transmitting coil) cross voltage

[0087] VLpp: Transmitting coil voltage peak value / transmitting signal peak value

[0088] Vpp: peak-to-peak voltage

[0089] Vpp1: first peak-to-peak voltage

[0090] Vpp2: Second peak-to-peak voltage DETAILED DESCRIPTION

[0091] The drawings in the present invention are all schematic, and are mainly intended to show the coupling relationship between various circuits and the relationship between various signal waveforms. The circuits, signal waveforms and frequencies are not drawn according to scale.

[0092] See also Figure 3 , Figure 3 FIG. 1 is a circuit block diagram showing a wireless power transmission circuit according to an embodiment of the present invention. Figure 3 As shown in FIG. 1 , in one embodiment, the wireless power transmission circuit 20 includes a reverse current circuit 201, a transmission control circuit 202, a resonant transmission circuit 203, and a voltage divider 204. In one embodiment, the reverse current circuit 201 is, for example, Figure 3 The half-bridge inverter circuit shown may also be a full-bridge inverter circuit or other types of inverter circuits. The inverter circuit 201 includes a plurality of switches coupled to a resonant transmitting circuit 203. The resonant transmitting circuit 203 includes a transmitting coil Lt (which may be considered as an inductor) and a resonant capacitor Ct coupled to each other. In one embodiment, please also refer to Figure 3 and Figure 5 , the transmitting control circuit 202 is used in the power supply process to generate a pulse width modulation control signal Spw to control multiple switches to convert the DC power VI and generate a wireless transmitting power in the resonant transmitting circuit 203 to wirelessly power the corresponding wireless power receiving circuit 30. On the other hand, the transmitting control circuit 202 is also used in the groping process to control multiple switches based on the operating frequency to generate a wireless test power in the resonant transmitting circuit 203. The transmitting control circuit 202 determines whether there is a foreign object and / or whether there is a wireless power receiving circuit 30 according to the transmitting signal corresponding to the wireless test power. The detailed operation steps of the groping process will be described in the subsequent embodiments. In one embodiment, the transmitting signal is related to the cross voltage VL of the transmitting coil Lt. In a preferred embodiment, the transmitting signal is the cross voltage VL of the transmitting coil Lt. The voltage divider 204 is used to generate a sensing voltage signal SVL according to the cross voltage VL of the transmitting coil Lt to provide it to the transmitting control circuit 202. In one embodiment, the sensing voltage signal SVL is related to the cross voltage VL of the transmitting coil Lt.

[0093] Figure 4A FIG. 1 is a circuit block diagram showing a transmission control circuit in a wireless power transmission circuit according to an embodiment of the present invention. This embodiment is only an exemplary embodiment. Figure 4AAs shown, in one embodiment, the emission control circuit 202 includes a peak detection circuit 2021, an analog-to-digital converter 2022, and a sub-control circuit 2023. The peak detection circuit 2021 is used to detect the peak value of the sensing voltage signal SVL and generate a peak voltage signal Spk. The analog-to-digital converter 2022 is used to convert the analog peak voltage signal Spk into a digital peak voltage signal Spkd. The sub-control circuit 2023 is used to generate a pulse width modulation control signal Spw according to the digital peak voltage signal Spkd.

[0094] Figure 4B FIG. 1 is a circuit block diagram showing a transmission control circuit in a wireless power transmission circuit according to another embodiment of the present invention. This embodiment is only an exemplary embodiment. Figure 4B As shown, in another embodiment, the emission control circuit 202 includes an analog-to-digital converter 2022, a peak calculation circuit 2024 and a sub-control circuit 2023. The analog-to-digital converter 2022 is used to convert the analog sensing voltage signal SVL into a digital sensing voltage signal SVLd. The peak calculation circuit 2024 is used to calculate the peak value of the digital sensing voltage signal SVLd to generate a digital peak voltage signal Spkd. The sub-control circuit 2023 is used to generate a pulse width modulation control signal Spw according to the digital peak voltage signal Spkd.

[0095] Figure 5 FIG. 1 is a schematic diagram showing a wireless power transmission circuit in several different situations according to an embodiment of the present invention. Figure 5 As shown, the upper oval represents the receiving end, and the lower oval represents the transmitting end. The receiving end can be in three situations, for example, it can be the receiving coil Lr in the wireless power receiving circuit 30, or it can be a foreign object 40, or there is no electromagnetic induction body. It should be noted that the foreign object 40 particularly refers to a non-wireless power receiving circuit with electromagnetic induction characteristics. The transmitting end can be, for example, the transmitting coil Lt in the wireless power transmitting circuit 20. In one embodiment, the wireless power receiving circuit 30 includes a resonant receiving circuit 301, a rectifier 302, an output control unit 303 and a load or battery 304. In this embodiment, the resonant receiving circuit 301 is used to receive the wireless transmitting power generated by the resonant transmitting circuit 203, and after rectification by the rectifier 302, it supplies power to the load or battery 304 through the output control unit 303. The resonant receiving circuit 301 includes a receiving coil Lr (which can be regarded as an inductor) and a resonant capacitor Cr coupled to each other. In one embodiment, the resonant transmitting circuit 203 and the resonant receiving circuit 301 can also perform in-band communication.

[0096] Figure 6 FIG. 1 is a frequency response diagram showing the peak voltage across the transmitting coil of a wireless power transmitting circuit according to an embodiment of the present invention. Figure 6As shown, the dotted line represents the frequency response curve of the peak voltage across the transmitting coil when there is a foreign object, the solid line represents the frequency response curve of the peak voltage across the transmitting coil when there is no electromagnetic induction body, and the dotted line represents the frequency response curve of the peak voltage across the transmitting coil when there is a wireless power receiver. When there is a foreign object, the resonant transmitting circuit 203 has a first response resonant frequency Fres_FO, and when there is a wireless power receiving circuit 30, the resonant transmitting circuit 203 has a second response resonant frequency Fres_RX. Figure 6 As shown, in one embodiment, the first response resonance frequency Fres_FO and the second response resonance frequency Fres_RX are located on different sides of the intrinsic resonance frequency Fres_null. In one embodiment, if Figure 6 The first response resonance frequency Fres_FO is higher than the second response resonance frequency Fres_RX. In another embodiment, the second response resonance frequency Fres_RX is higher than the first response resonance frequency Fres_FO.

[0097] Since the response resonant frequency of the resonant transmitting circuit 203 is different and its Q value (quality factor) is also different when the receiving end is in different situations, the situation of the receiving end can be determined by the characteristics of the transmitting signal measured by the resonant transmitting circuit 203 at one or more operating frequencies, such as the peak value of the transmitting signal or the rate of change of the peak value to the frequency, etc. The detailed embodiments will be described in detail later.

[0098] Figure 7 1 is a waveform diagram of a transmission signal (transmitting coil voltage) measured when a wireless power transmission circuit transmits wireless test power in an exploration process according to an embodiment of the present invention. The transmitting coil voltage VL, the first peak-to-peak voltage Vpp1, the second peak-to-peak voltage Vpp2, the first operation cycle Top1 and the second operation cycle Top2 are shown in FIG. Figure 7 In one embodiment, when the wireless power transmitting circuit transmits the wireless test power in the exploration procedure, it is divided into two stages. The first stage transmits the wireless test power based on the first operation cycle Top1 (corresponding to the first operation frequency Fop1), and the second stage transmits the wireless test power based on the second operation cycle Top2 (corresponding to the second operation frequency Fop2), wherein the first operation frequency Fop1 and the second operation frequency Fop2 each have an offset frequency that is not 0 with the intrinsic resonant frequency Fres_null of the resonant transmitting circuit 203. In this embodiment, the first operation cycle Top1 (corresponding to the first operation frequency Fop1) is different from the second operation cycle Top2, and therefore, the first peak-to-peak voltage Vpp1 of the transmitting coil cross voltage VL in the first stage and the second peak-to-peak voltage Vpp2 in the second stage are also different.

[0099] Figure 8 1 is a waveform diagram of the transmission signal (transmitting coil voltage) measured when the wireless power transmitting circuit transmits the wireless test power in the exploration process according to another embodiment of the present invention. In this embodiment, when the wireless power transmitting circuit transmits the wireless test power in the exploration process, there is only one test phase. In this test phase, the wireless power transmitting circuit transmits the wireless test power based on an operation cycle Top (corresponding to the operation frequency Fop). The transmitting coil voltage VL, the peak-to-peak voltage Vpp and the operation cycle Top are shown in FIG. Figure 8 .

[0100] Please also refer to Figure 8 , Fig. 9 and Fig.11A , Fig. 9 is a frequency response diagram showing the peak voltage across the transmitting coil of the wireless power transmitting circuit according to an embodiment of the present invention. Fig.11A is a schematic diagram showing a judgment interval of a peak voltage across a transmitting coil of a wireless power transmitting circuit according to an embodiment of the present invention. Fig. 9 As shown, the wireless power transmitting circuit can pre-measure and obtain the foreign object peak threshold FO_vpp_TH and / or the receiving peak threshold RX_vpp_TH, and then determine the situation of the receiving end through the relationship between the peak value of the transmitting coil cross-voltage (transmitting signal) of the wireless power transmitting circuit and the thresholds.

[0101] Continue reading Fig. 9 and Fig.11A In one embodiment, the operating frequency Fop and the intrinsic resonance frequency Fres_null of the resonant transmitting circuit 203 have an offset frequency Fofs that is not 0. When the peak voltage across the transmitting coil (also referred to as the peak value of the transmitting signal) VLpp is, for example, the peak voltage across the transmitting coil FO_vpp_fop, it exceeds (for example but not limited to being greater than) the foreign object peak threshold FO_vpp_TH, it can be determined that there is a foreign object (FO). Here, the so-called "existence" means that a foreign object with electromagnetic induction characteristics is close to the transmitting coil, and the degree of its proximity is sufficient to cause the peak voltage across the transmitting coil VLpp to change and exceed the foreign object peak threshold FO_vpp_TH.

[0102] On the other hand, when the transmitting coil cross-voltage peak value VLpp is, for example, the transmitting coil cross-voltage peak value RX_vpp_fop, it exceeds (for example but not limited to being less than) the receiving peak threshold value RX_vpp_TH, thereby determining that the wireless power receiving circuit 30 exists (RX). When the transmitting coil cross-voltage peak value VLpp is, for example, the transmitting coil cross-voltage peak value Null_vpp_fop, it is between the foreign object peak threshold value FO_vpp_TH and the receiving peak threshold value RX_vpp_TH, thereby determining that the electromagnetic induction body does not exist (Nll).

[0103] Please also see Figure 7 , Fig. 10A , Fig. 10B and Fig. 11B , Fig. 10A FIG. 4 is a frequency response diagram showing a peak voltage across a transmitting coil of a wireless power transmitting circuit according to another embodiment of the present invention. Fig. 10B According to an embodiment of the present invention, Fig. 10A A partial enlarged view of . Fig. 11B is a schematic diagram showing a judgment interval of a change rate of a voltage peak value across a transmitting coil of a wireless power transmitting circuit relative to a frequency according to an embodiment of the present invention. Fig. 10A , Fig. 10B and Fig. 11B As shown, the wireless power transmitting circuit can pre-measure and obtain the foreign object change rate threshold FO_slope_TH and / or the receiving change rate threshold RX_slope_TH, and then determine the situation of the receiving end through the peak value of the peak voltage across the transmitting coil (transmitting signal) of the wireless power transmitting circuit corresponding to the peak value-frequency change rate of the operating frequency and the magnitude relationship between the foreign object change rate thresholds.

[0104] The peak-frequency change rate is obtained by dividing the difference between the first transmitting coil voltage peak value (also referred to as the first transmitting signal peak value) and the second transmitting coil voltage peak value (also referred to as the second transmitting signal peak value) corresponding to the first operating frequency Fop1 and the second operating frequency Fop2 respectively by the difference between the first operating frequency Fop1 and the second operating frequency Fop2. Fig. 10A and Fig. 10BAs shown, the peak-frequency change rate m1 is obtained by dividing the difference between the transmitting coil cross-voltage peak values ​​RX_vpp_fop1 and the transmitting coil cross-voltage peak values ​​RX_vpp_fop2 corresponding to the first operating frequency Fop1 and the second operating frequency Fop2 respectively by the difference between the first operating frequency Fop1 and the second operating frequency Fop2. Similarly, the peak-frequency change rate m2 is obtained by dividing the difference between the transmitting coil cross-voltage peak values ​​Null_vpp_fop1 and the transmitting coil cross-voltage peak value Null_vpp_fop2 corresponding to the first operating frequency Fop1 and the second operating frequency Fop2 respectively by the difference between the first operating frequency Fop1 and the second operating frequency Fop2. The peak-frequency change rate m3 is obtained by dividing the difference between the transmitting coil cross-voltage peak values ​​FO_vpp_fop1 and the transmitting coil cross-voltage peak values ​​FO_vpp_fop2 corresponding to the first operating frequency Fop1 and the second operating frequency Fop2 respectively by the difference between the first operating frequency Fop1 and the second operating frequency Fop2.

[0105] In one embodiment, when the peak-frequency change rate is, for example, the peak-frequency change rate m3, it exceeds (for example, but not limited to, greater than) the foreign object change rate threshold FO_slope_TH, thereby determining that a foreign object exists (FO). When the peak-frequency change rate is, for example, the peak-frequency change rate m1, it exceeds (for example, but not limited to, less than) the receiving change rate threshold RX_slope_TH, thereby determining that a wireless power receiving circuit 30 exists (RX). When the peak-frequency change rate is, for example, the peak-frequency change rate m2, it is between the foreign object change rate threshold FO_slope_TH and the receiving change rate threshold RX_slope_TH, then determining that no electromagnetic induction body exists (Nll).

[0106] Figures 12A to 12J , Figure 13A-13B , Fig.14 and Fig.15 FIG. 1 is a flowchart showing the steps of the exploration procedure of the wireless power transmission circuit according to an embodiment of the present invention. Fig. 12A As shown, the exploration procedure 50 includes, in step S100, measuring the peak value of the transmission signal corresponding to the wireless test power supply. Then, step S250 and / or step S350 are performed. In step S250, it is determined whether there is a foreign object according to the peak value of the transmission signal, and if so, it is determined that there is a foreign object. If not and step S350 has not been performed, step S350 is performed. In step S350, it is determined whether there is a wireless power receiving circuit according to the peak value of the transmission signal, and if so, step S700 is performed, and if not and step S250 has not been performed, step S250 is performed. In step S700, a power supply procedure is performed. In one embodiment, the power supply procedure may include further digital exploration steps.

[0107] like Fig. 12B As shown, in another embodiment, the exploration procedure 50 includes, in step S100, measuring the peak value of the transmission signal corresponding to the wireless test power supply. Then, in step S200, judging whether there is a foreign object according to whether the peak value of the transmission signal exceeds (for example but not limited to being greater than) the foreign object peak value threshold FO_vpp_TH. If so, it is judged that there is a foreign object. Fig. 12C As shown, this embodiment and Fig. 12B The difference between the embodiment of the present invention is that the present embodiment replaces step S200 with step S300. In step S300, whether a foreign object exists is determined based on whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency exceeds (for example but not limited to being greater than) the foreign object change rate threshold FO_slope_TH. The remaining steps are the same as Fig. 12B The embodiments are similar, so the detailed description is omitted.

[0108] like Fig.12D As shown, this embodiment and Fig. 12B The difference between the embodiment of the present invention is that, after step S200, the present embodiment further includes step S300. In step S300, it is determined whether a foreign object exists according to whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency is greater than the foreign object change rate threshold FO_slope_TH. The remaining steps are the same as Fig. 12B The embodiment of is similar, so the detailed description is omitted. Fig.12E As shown, this embodiment and Fig. 12B The difference between the embodiment of the present invention is that the present embodiment further includes a step S300 before step S200 and after step S100. In step S300, it is determined whether a foreign object exists according to whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency is greater than the foreign object change rate threshold FO_slope_TH. If so, step S200 is performed. The remaining steps are the same as Fig. 12B The embodiments are similar, so the detailed description is omitted.

[0109] like Fig.12F As shown, in another embodiment, the exploration procedure 50 includes, in step S100, measuring the peak value of the transmission signal corresponding to the wireless test power supply. Then, in step S500, judging whether there is a wireless power receiving circuit according to whether the peak value of the transmission signal exceeds (for example but not limited to less than) the receiving peak threshold RX_vpp_TH. If so, proceed to step S700. In step S700, the power supply procedure is performed. Figure 12G As shown, this embodiment and Fig.12FThe difference between the embodiment of the present invention is that the present embodiment replaces step S500 with step S600. In step S600, it is determined whether a wireless power receiving circuit exists according to whether the peak value of the transmitted signal corresponding to the peak value-frequency change rate of the operating frequency exceeds (for example but not limited to less than) the receiving change rate threshold RX_slope_TH. The remaining steps are the same as Fig.12F The embodiments are similar, so the detailed description is omitted.

[0110] like Fig.12H As shown, this embodiment and Fig.12F The difference between the embodiment of the present invention is that, after step S500, the present embodiment further includes step S600. In step S600, it is determined whether a wireless power receiving circuit exists according to whether the peak value of the transmitted signal corresponding to the peak value-frequency change rate of the operating frequency is less than the receiving change rate threshold RX_slope_TH. The remaining steps are the same as Fig.12F The embodiment of is similar, so the detailed description is omitted. Fig.12I As shown, this embodiment and Fig.12F The difference between the embodiment of the present invention is that the present embodiment further includes a step S600 before step S500 and after step S100. In step S600, it is determined whether a wireless power receiving circuit exists according to whether the peak value of the transmitted signal corresponding to the peak value-frequency change rate of the operating frequency is less than the receiving change rate threshold RX_slope_TH. If so, step S500 is performed. The remaining steps are the same as Fig.12F The embodiments are similar, so the detailed description is omitted.

[0111] like Fig.12J As shown, this embodiment and Fig. 12A The embodiment is similar to that of the present embodiment, except that step S250 of the present embodiment includes step S200 and step S300, and step S350 of the present embodiment includes step S500 and step S600. In step S200, whether a foreign object exists is determined based on whether the peak value of the transmitted signal is greater than the foreign object peak threshold FO_vpp_TH. In step S300, whether a foreign object exists is determined based on whether the peak-frequency change rate of the peak value of the transmitted signal corresponding to the operating frequency is greater than the foreign object change rate threshold FO_slope_TH. In step S500, whether a wireless power receiving circuit exists is determined based on whether the peak value of the transmitted signal is less than the receiving peak threshold RX_vpp_TH. In step S600, whether a wireless power receiving circuit exists is determined based on whether the peak-frequency change rate of the peak value of the transmitted signal corresponding to the operating frequency is less than the receiving change rate threshold RX_slope_TH. As Fig.12JAs shown, the execution order of steps S200, S300, S500 and S600 can be varied in many ways. For example, step S200 may be executed first, followed by step S300, then step S600, and finally step S500 before entering step S700. Step S300 may also be executed first, followed by step S200, then step S600, and finally step S500 before entering step S700. Step S200 may also be executed first, followed by step S300, then step S500, and finally step S600 before entering step S700. Step S300 may also be executed first, followed by step S200, then step S500, and finally step S600 before entering step S700. The remaining steps are similar to those in the previous step. Fig. 12A The embodiments are similar, so the detailed description is omitted.

[0112] like Fig.13A As shown, this embodiment and Fig. 12A The difference between the embodiment of the present invention and the embodiment of the present invention is that if the judgment result of step S250 of the present invention is yes, the process returns to step S100. If the judgment result of step S350 of the present invention is no and step S250 has been performed, the process returns to step S100. The remaining steps are the same as those of the embodiment of the present invention. Fig. 12A The embodiment of is similar, so the detailed description is omitted. Fig. 13B As shown, this embodiment and Fig.13A The difference between the embodiment of the present invention is that if the judgment result of step S250 of the present invention is yes, step S400 is performed first, and then step S100 is returned. In step S400, since it is judged that there is a foreign object, the present embodiment can increase the delay time and / or reduce the power level of the wireless test power supply, thereby achieving the effect of power saving and protecting the wireless power supply transmitting circuit to extend the service life. Fig. 13B Examples and Fig.13A Another difference of the embodiment is that if the judgment result of step S350 of this embodiment is no and step S250 has been performed, then step S800 is performed. In step S800, a cumulative number is accumulated until the cumulative number exceeds the preset counting threshold, and then step S900 is performed, otherwise, the process returns to step S100. In step S900, after the power level of the wireless test power source is increased, the process returns to step S100. The remaining steps are the same as Fig.13A The embodiments are similar, so the detailed description is omitted.

[0113] like Fig.14 As shown, this embodiment and Fig. 13BThe difference between the embodiment of the present invention is that step S250 of the present invention includes step S200 and step S300, and step S350 of the present invention includes step S500 and step S600. In step S200, it is determined whether a foreign object exists according to whether the peak value of the transmitted signal is greater than the foreign object peak threshold FO_vpp_TH. If so, step S300 is performed, otherwise step S500 is performed. In step S300, it is determined whether a foreign object exists according to whether the peak-frequency change rate of the peak value of the transmitted signal corresponding to the operating frequency exceeds (for example but not limited to being greater than) the foreign object change rate threshold FO_slope_TH. If so, step S400 is performed, otherwise step S800 is performed. In step S500, it is determined whether a wireless power receiving circuit exists according to whether the peak value of the transmitted signal is less than the receiving peak threshold RX_vpp_TH. If so, step S600 is performed, otherwise step S800 is performed. In step S600, it is determined whether there is a wireless power receiving circuit according to whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency is less than the receiving change rate threshold RX_slope_TH. If so, step S700 is performed, otherwise step S800 is performed. The remaining steps are the same as Fig. 13B The embodiments are similar, so the detailed description is omitted.

[0114] like Fig.15 As shown, this embodiment and Fig.14 The difference between the embodiment of the present invention is that if the judgment result of step S300 is "No", step S600 is performed. The remaining steps are the same as Fig.14 The embodiments are similar, so the detailed description is omitted.

[0115] As described above, the wireless power transmitting circuit of the present invention can utilize the peak value or peak-frequency change rate of the transmitting signal of the wireless power transmitting coil to detect foreign objects and the wireless power receiving circuit without the need for an additional detection coil circuit, and can only detect the stable peak value of low-power transmission without waking up the wireless receiving circuit. Therefore, it can be used as an analog exploration method that can accurately detect and save power before digital exploration.

[0116] The present invention has been described above with respect to the preferred embodiment, but the above is only to make it easy for those skilled in the art to understand the content of the present invention, and is not used to limit the scope of rights of the present invention. The various embodiments described are not limited to individual applications, but can also be used in combination. For example, two or more embodiments can be used in combination, and part of the components in one embodiment can also be used to replace the corresponding components in another embodiment. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, the present invention refers to "processing or calculating or generating an output result according to a certain signal", which is not limited to the signal itself, but also includes, when necessary, converting the signal to voltage and current, current and voltage, and / or ratio conversion, and then processing or calculating according to the converted signal to generate an output result. It can be seen from this that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which are not listed one by one here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A wireless power transmission circuit, comprising: A reverse current circuit includes a plurality of switches coupled to a resonant transmitting circuit, wherein the resonant transmitting circuit includes a transmitting coil and a resonant capacitor coupled to each other; as well as a transmitting control circuit, used in a power supply procedure S700 to generate a pulse width modulation control signal to control the plurality of switches to generate a wireless transmitting power in the resonant transmitting circuit to wirelessly supply power to a corresponding wireless power receiving circuit, and the transmitting control circuit is used in a search procedure to control the plurality of switches to generate a wireless test power in the resonant transmitting circuit based on an operating frequency, the transmitting control circuit determines whether there is a foreign object and / or whether the wireless power receiving circuit exists according to a transmitting signal, wherein the transmitting signal is related to a voltage across the transmitting coil; The operating frequency and an intrinsic resonant frequency of the resonant transmitting circuit have an offset frequency that is not zero; The exploration procedure includes the following steps: S100: measuring the peak value of the transmission signal corresponding to the wireless test power supply; The exploration process also includes: S250: Determine whether the foreign object exists according to the peak value of the transmission signal; and / or S350: Determine whether the wireless power receiving circuit exists according to the peak value of the transmission signal, wherein when it is determined that the wireless power receiving circuit exists, perform the power supply procedure S700.

2. The wireless power transmission circuit according to claim 1, wherein: The step S250 includes: S200: Determine whether the foreign object exists according to whether the peak value of the transmitted signal exceeds a foreign object peak value threshold; and / or S300: Determine whether the foreign object exists according to whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency exceeds a foreign object change rate threshold.

3. The wireless power transmission circuit according to claim 2, wherein: The step S350 includes: S500: Determine whether the wireless power receiving circuit exists according to whether the peak value of the transmission signal exceeds a receiving peak threshold; and / or S600: Determine whether the wireless power receiving circuit exists according to whether the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency exceeds a receiving change rate threshold.

4. The wireless power transmission circuit according to claim 3, wherein: When the foreign object exists, the resonant transmitting circuit has a first response resonant frequency, wherein when the wireless power receiving circuit exists, the resonant transmitting circuit has a second response resonant frequency, wherein the first response resonant frequency and the second response resonant frequency are respectively located on different sides of the intrinsic resonant frequency.

5. The wireless power transmission circuit according to claim 4, wherein: The first response resonance frequency is higher than the intrinsic resonance frequency, and the intrinsic resonance frequency is higher than the second response resonance frequency.

6. The wireless power transmission circuit according to claim 5, wherein: The step S200 includes judging whether the foreign object exists according to whether the peak value of the transmitted signal is greater than the foreign object peak threshold, wherein the step S500 includes judging whether the wireless power receiving circuit exists according to whether the peak value of the transmitted signal is less than the receiving peak threshold, wherein the receiving peak threshold is less than the foreign object peak threshold.

7. The wireless power transmission circuit according to claim 5, wherein: The step S300 includes judging whether the foreign object exists according to whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is greater than the absolute value of the foreign object change rate threshold, and the step S600 includes judging whether the wireless power receiving circuit exists according to whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is less than the absolute value of the receiving change rate threshold, wherein the absolute value of the receiving change rate threshold is less than the absolute value of the foreign object change rate threshold.

8. The wireless power transmission circuit according to claim 3, wherein: The peak-frequency change rate of the peak value of the transmission signal corresponding to the operating frequency is obtained by dividing the difference between a first transmission signal peak value and a second transmission signal peak value corresponding to a first operating frequency and a second operating frequency respectively by the difference between the first operating frequency and the second operating frequency.

9. The wireless power transmission circuit according to claim 8, wherein: The first operating frequency is the same as the operating frequency, so that the peak value of the first transmitting signal can be used as the peak value of the transmitting signal. 10 . The wireless power transmission circuit as claimed in claim 1 , wherein when it is determined in step S250 that the foreign object exists, the process returns to step S100 .

11. The wireless power transmission circuit according to claim 10, wherein: The exploration procedure further includes a foreign body operation step S400, wherein when it is determined in step S250 that the foreign body exists, the foreign body operation step S400 is further performed, and then the process returns to step S100, wherein the foreign body operation step S400 includes: Add a delay time, and / or reduce the power level of the wireless test power supply.

12. The wireless power transmission circuit according to claim 3, wherein: When it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, the process returns to step S100 .

13. The wireless power transmission circuit according to claim 12, wherein: The exploration procedure further includes step S900, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S900 is further performed and then the process returns to step S100, wherein step S900 includes: Increase the power level of the wireless test power supply.

14. The wireless power transmission circuit according to claim 13, wherein: The exploration procedure further includes step S800, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S800 is further performed before entering step S100 or step S900, wherein step S800 includes: The step S900 is entered only after a cumulative number of times is accumulated and exceeds a preset counting threshold, otherwise the process returns to the step S100 .

15. A method for detecting a wireless power receiver and a foreign object, comprising: In a power supply procedure S700, a resonant transmitting circuit is controlled to generate a wireless transmitting power to wirelessly supply power to a corresponding wireless power receiving circuit; as well as In an exploration procedure, the resonant transmitting circuit is controlled to generate a wireless test power source based on an operating frequency, and a transmission signal of the resonant transmitting circuit is used to determine whether there is a foreign object and / or whether the wireless power receiving circuit exists, wherein the operating frequency and an intrinsic resonant frequency of the resonant transmitting circuit have an offset frequency that is not zero; The exploration procedure includes the following steps: S100: measuring the peak value of the transmission signal corresponding to the wireless test power supply; The exploration process also includes: S250: Determine whether the foreign object exists according to the peak value of the transmission signal; and / or S350: Determine whether the wireless power receiving circuit exists according to the peak value of the transmission signal, wherein when it is determined that the wireless power receiving circuit exists, perform the power supply procedure S700.

16. The method for detecting a wireless power receiver and a foreign object as claimed in claim 15, wherein: The step S250 includes: S200: Determine whether the foreign object exists according to whether the peak value of the transmitted signal exceeds a foreign object peak value threshold; and / or S300: Determine whether the foreign object exists according to whether the peak value of the transmission signal corresponding to the peak value-frequency change rate of the operating frequency exceeds a foreign object change rate threshold.

17. The method for detecting a wireless power receiver and a foreign object as claimed in claim 16, wherein: The step S350 includes: S500: Determine whether the wireless power receiving circuit exists according to whether the peak value of the transmission signal exceeds a receiving peak threshold; and / or S600: Determine whether the wireless power receiving circuit exists according to whether the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency exceeds a receiving change rate threshold.

18. The method for detecting a wireless power receiver and a foreign object as claimed in claim 17, wherein: When the foreign object exists, the resonant transmitting circuit has a first response resonant frequency, wherein when the wireless power receiving circuit exists, the resonant transmitting circuit has a second response resonant frequency, wherein the first response resonant frequency and the second response resonant frequency are respectively located on different sides of the intrinsic resonant frequency.

19. The method for detecting a wireless power receiver and a foreign object as claimed in claim 18, wherein: The first response resonance frequency is higher than the intrinsic resonance frequency, and the intrinsic resonance frequency is higher than the second response resonance frequency.

20. The method for detecting a wireless power receiver and a foreign object as claimed in claim 19, wherein: The step S200 includes judging whether the foreign object exists according to whether the peak value of the transmitted signal is greater than the foreign object peak threshold, wherein the step S500 includes judging whether the wireless power receiving circuit exists according to whether the peak value of the transmitted signal is less than the receiving peak threshold, wherein the receiving peak threshold is less than the foreign object peak threshold.

21. The method for detecting a wireless power receiver and a foreign object as claimed in claim 19, wherein: The step S300 includes judging whether the foreign object exists according to whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is greater than the absolute value of the foreign object change rate threshold, and the step S600 includes judging whether the wireless power receiving circuit exists according to whether the absolute value of the peak-frequency change rate of the peak value of the transmitting signal corresponding to the operating frequency is less than the absolute value of the receiving change rate threshold, wherein the absolute value of the receiving change rate threshold is less than the absolute value of the foreign object change rate threshold.

22. The method for detecting a wireless power receiver and a foreign object as claimed in claim 17, wherein: The peak-frequency change rate of the peak value of the transmission signal corresponding to the operating frequency is obtained by dividing the difference between a first transmission signal peak value and a second transmission signal peak value corresponding to a first operating frequency and a second operating frequency respectively by the difference between the first operating frequency and the second operating frequency.

23. The method for detecting a wireless power receiver and a foreign object as claimed in claim 22, wherein: The first operating frequency is the same as the operating frequency, so that the peak value of the first transmitting signal can be used as the peak value of the transmitting signal.

24. The method for detecting a wireless power receiver and a foreign object as claimed in claim 15, wherein: When it is determined in step S250 that the foreign matter exists, the process returns to step S100 .

25. The method for detecting a wireless power receiver and a foreign object as claimed in claim 24, wherein: The exploration procedure further includes a foreign body operation step S400, wherein when it is determined in step S250 that the foreign body exists, the foreign body operation step S400 is further performed, and then the process returns to step S100, wherein the foreign body operation step S400 includes: Add a delay time, and / or reduce the power level of the wireless test power supply.

26. The method for detecting a wireless power receiver and a foreign object as claimed in claim 17, wherein: When it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, the process returns to step S100 .

27. The method for detecting a wireless power receiver and a foreign object as claimed in claim 26, wherein: The exploration procedure further includes step S900, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S900 is further performed and then the process returns to step S100, wherein step S900 includes: Increase the power level of the wireless test power supply.

28. The method for detecting a wireless power receiver and a foreign object as claimed in claim 27, wherein: The exploration procedure further includes step S800, wherein when it is determined in step S300 that the foreign object does not exist and in step S600 that the wireless power receiving circuit does not exist, step S800 is further performed before entering step S100 or step S900, wherein step S800 includes: The step S900 is entered only after a cumulative number of times is accumulated and exceeds a preset counting threshold, otherwise the process returns to the step S100 .

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