Wireless electric energy receiving circuit, electronic equipment and wireless charging system

Abstract

The invention discloses a wireless electric energy receiving circuit, electronic equipment and a wireless charging system, and relates to the technical field of circuits. The wireless electric energy receiving circuit comprises a receiving coil, an impedance compensation module, a rectification module, an impedance adjusting module and a processing module. Wherein the receiving coil, the impedance compensation module and the rectifier module are connected in series for supplying power to a load. The impedance adjusting module and the impedance compensation module are connected in parallel. And the processing module controls the waveform of the electric signal in the receiving coil by controlling the on and off of the impedance adjusting module, so as to transmit communication information to the wireless electric energy transmitting circuit. Thus, a communication capacitor connected in parallel with the rectification module is removed, and the problem that the communication capacitor connected in parallel with the rectification module has large plate vibration, and consequently large capacitor howling is generated can be avoided.

Description

Wireless power receiving circuit, electronic device and wireless charging system Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a wireless power receiving circuit, an electronic device, and a wireless charging system. Background Art

[0002] Electronic devices include mobile phones, tablets, and the like. Generally, these electronic devices include a wireless power receiving circuit, which is used to implement wireless charging. The wireless power receiving circuit may include a receiving coil, an impedance compensation module, and a rectifier module. The impedance compensation module is connected between the receiving coil and the rectifier module. When the receiving coil is operating, it outputs alternating current (AC) to the rectifier module. The rectifier module rectifies the AC power and outputs DC power to the electronic device's load, thereby powering the load.

[0003] In related technologies, the wireless power receiving circuit also includes a communication capacitor connected in parallel with the rectifier module. When the wireless power receiving circuit is operating, the waveform of the electrical signal in the receiving coil can be controlled by controlling the conduction of the branch containing the communication capacitor, thereby transmitting communication information to the wireless power transmitting circuit.

[0004] However, as wireless charging power increases, the voltage output by the receiving coil increases, causing the voltage across the communication capacitor to also increase. In this case, the piezoelectric effect causes the communication capacitor to experience greater plate vibration, resulting in significant capacitor noise, which affects the user experience.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a wireless power receiving circuit, an electronic device, and a wireless charging system, which can effectively improve the problem of large capacitive howling generated during wireless charging of electronic devices, thereby improving the user experience. The technical solution is as follows:

[0007] In a first aspect, a wireless power receiving circuit is provided. The wireless power receiving circuit is applied to an electronic device to implement wireless charging of the electronic device. The wireless power receiving circuit includes a receiving coil, an impedance compensation module, a rectifier module, an impedance adjustment module, and a processing module.

[0008] The first end of the receiving coil is connected to the first end of the impedance compensation module. The second end of the impedance compensation module is connected to the first input end of the rectifier module. The second end of the receiving coil is connected to the second input end of the rectifier module. The output end of the rectifier module is connected to a load of the electronic device. In this way, when the wireless power receiving circuit is operating, the receiving coil can output alternating current (AC) to the rectifier module via the impedance compensation module. The rectifier module rectifies the AC power and outputs DC power to the load, thereby supplying power to the load.

[0009] The first end of the impedance adjustment module is connected to the first end of the impedance compensation module, and the second end of the impedance adjustment module is connected to the second end of the impedance compensation module. In other words, the impedance adjustment module and the impedance compensation module are connected in parallel. The control end of the impedance adjustment module is connected to the processing module so that the processing module can control the impedance adjustment module to be turned on and off. Here, the processing module can change the waveform of the electrical signal in the receiving coil by controlling the impedance adjustment module to be turned on and off. This change in the waveform of the electrical signal in the receiving coil is used to transmit communication information.

[0010] In an embodiment of the present application, a wireless power receiving circuit includes a receiving coil, an impedance compensation module, a rectifier module, an impedance adjustment module, and a processing module. The receiving coil, impedance compensation module, and rectifier module are connected in series to supply power to a load, thereby achieving wireless charging. The impedance adjustment module and the impedance compensation module are connected in parallel. The processing module controls the waveform of the electrical signal in the receiving coil by turning the impedance adjustment module on and off, thereby transmitting communication information to the wireless power transmitting circuit. This eliminates the communication capacitor connected in parallel with the rectifier module, thereby avoiding the problem of large plate vibration in the communication capacitor connected in parallel with the rectifier module, which can cause large capacitor noise. In this embodiment of the present application, the impedance adjustment module may include a communication capacitor. In other words, the communication capacitor is connected in parallel with the impedance compensation module. Because the voltage of the impedance compensation module is much lower than that of the rectifier module in the series circuit formed by the receiving coil, impedance compensation module, and rectifier module, the communication capacitor is connected in parallel with the impedance compensation module. Therefore, compared to related art, the voltage across the communication capacitor can be significantly reduced, thereby reducing the plate vibration of the communication capacitor, improving the problem of large capacitor noise generated during wireless charging of electronic devices, and thus improving the user experience.

[0011] In some embodiments, the impedance adjustment module includes a first impedance unit and a switch unit connected in series. Specifically, the first end of the first impedance unit is connected to the first end of the impedance compensation module. The second end of the first impedance unit is connected to the first end of the switch unit. The second end of the switch unit is connected to the second end of the impedance compensation module. The processing module is connected to the control end of the switch unit. Here, the processing module is configured to control the on and off state of the switch unit to control the on and off state of the impedance adjustment module.

[0012] Furthermore, the impedance adjustment module may further include a second impedance unit. A first end of the second impedance unit is connected to the second end of the switch unit, and a second end of the second impedance unit is connected to the second end of the impedance compensation module. In other words, in this case, the first impedance unit, the switch unit, and the second impedance unit are connected in series to form the impedance adjustment module.

[0013] The first impedance unit includes a first capacitor, and the second impedance unit includes a second capacitor. Alternatively, or alternatively, the first impedance unit includes a first resistor, and the second impedance unit includes a second resistor. Here, both the first capacitor and the second capacitor are communication capacitors.

[0014] In some embodiments, the switch unit includes a first transistor and a second transistor. The first electrode of the first transistor is connected to the second end of the first impedance unit. The second electrode of the first transistor is connected to the second electrode of the second transistor. The first electrode of the second transistor is connected to the second end of the impedance compensation module. In other words, the first transistor and the second transistor are connected in series to form the switch unit. The processing module is connected to the control electrode of the first transistor, the control electrode of the second transistor, the second electrode of the first transistor, and the second electrode of the second transistor to control the conduction and disconnection of the first transistor and the second transistor.

[0015] In some specific embodiments, the first transistor and the second transistor are both N-type transistors. In this case, the first electrode of the first transistor and the first electrode of the second transistor are both drains of the N-type transistors, and the second electrode of the first transistor and the second electrode of the second transistor are both sources of the N-type transistors.

[0016] In some embodiments, the processing module includes a control unit and a modulation unit. The output of the control unit is connected to the input of the modulation unit. The output of the modulation unit is connected to the control terminal of the impedance adjustment module. The control unit is configured to generate a control signal based on the communication information and transmit the control signal to the modulation unit. The modulation unit is configured to modulate the control signal to generate a modulation signal. The modulation signal is used to control the on / off operation of the impedance adjustment module.

[0017] In some embodiments, the impedance compensation module includes a third capacitor. A first plate of the third capacitor is connected to a first end of the receiving coil and a first end of the impedance adjustment module. A second plate of the third capacitor is connected to a first input end of the rectifier module and a second end of the impedance adjustment module.

[0018] Furthermore, the impedance compensation module may further include a fourth capacitor and an inductor. The second plate of the third capacitor is connected to the first plate of the fourth capacitor and the first end of the inductor. The second end of the inductor is connected to the first input end of the rectifier module and the second end of the impedance adjustment module. The second plate of the fourth capacitor is connected to the second end of the receiving coil.

[0019] In some embodiments, the rectifier module is a full-wave rectifier circuit or a half-wave rectifier circuit.

[0020] In a second aspect, an electronic device is provided. The electronic device includes a load and the wireless power receiving circuit according to any one of the first aspects. The output terminal of the wireless power receiving circuit is connected to the load for outputting an electrical signal to the load.

[0021] In some embodiments, the load may be at least one of an energy storage module, a system-on-chip, a display screen, a speaker, a microphone, a camera, a motor, a sensor, etc. in an electronic device.

[0022] In a third aspect, a wireless charging system is provided, comprising a wireless charging device and an electronic device as described in any one of the second aspects. The wireless charging device is used to wirelessly charge the electronic device. The wireless charging device includes a wireless power transmission circuit.

[0023] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic diagram of the appearance of an electronic device;

[0025] FIG2 is a schematic diagram of the appearance of a wireless charging device;

[0026] FIG3 is a schematic diagram of a scenario in which a first wireless charging device wirelessly charges an electronic device;

[0027] FIG4 is a schematic diagram of a scenario in which a second wireless charging device wirelessly charges an electronic device;

[0028] FIG5 is a circuit diagram of a wireless charging system for power transmission;

[0029] FIG6 is a circuit diagram of a wireless charging system for power transmission and communication in the related art;

[0030] FIG7 is a circuit diagram of a wireless charging system for power transmission and ASK modulation in the related art;

[0031] FIG8 is a circuit diagram of a wireless power receiving circuit of an electronic device in the related art;

[0032] FIG9 is an equivalent circuit diagram of a wireless charging system when a switch unit is turned off in the related art;

[0033] FIG10 is an equivalent circuit diagram of a wireless charging system when a switch unit is turned on in the related art;

[0034] FIG11 is a circuit structure diagram of a first wireless power receiving circuit provided in an embodiment of the present application;

[0035] FIG12 is a circuit structure diagram of a second wireless power receiving circuit provided in an embodiment of the present application;

[0036] FIG13 is a circuit diagram of a first wireless power receiving circuit provided in an embodiment of the present application;

[0037] FIG14 is a circuit structure diagram of a third wireless power receiving circuit provided in an embodiment of the present application;

[0038] FIG15 is a circuit diagram of a second wireless power receiving circuit provided in an embodiment of the present application;

[0039] FIG16 is a circuit diagram of a third wireless power receiving circuit provided in an embodiment of the present application;

[0040] FIG17 is a circuit diagram of a fourth wireless power receiving circuit provided in an embodiment of the present application;

[0041] FIG18 is a circuit diagram of a fifth wireless power receiving circuit provided in an embodiment of the present application;

[0042] FIG19 is a circuit diagram of a sixth wireless power receiving circuit provided in an embodiment of the present application;

[0043] FIG20 is a circuit diagram of a first rectifier module provided in an embodiment of the present application;

[0044] FIG21 is a circuit diagram of a second rectifier module provided in an embodiment of the present application;

[0045] FIG22 is a circuit diagram of a wireless charging system for power transmission and ASK modulation provided by an embodiment of the present application;

[0046] FIG23 is a circuit diagram of a first inverter module provided in an embodiment of the present application;

[0047] FIG24 is a circuit diagram of a second inverter module provided in an embodiment of the present application;

[0048] FIG25 is a circuit diagram of a wireless charging system for power transmission and ASK communication provided by an embodiment of the present application;

[0049] FIG26 is an equivalent circuit diagram of a wireless charging system when a switch unit is turned off, provided by an embodiment of the present application;

[0050] FIG27 is an equivalent circuit diagram of a wireless charging system when a switch unit is turned on, provided by an embodiment of the present application;

[0051] FIG28 is a curve diagram of voltage variation across a third capacitor provided in an embodiment of the present application;

[0052] FIG29 is a diagram showing electrical signal waveforms at various locations of a simulation circuit of a wireless charging system in the related art;

[0053] FIG30 is a diagram showing electrical signal waveforms at various locations of a simulation circuit of a wireless charging system provided by an embodiment of the present application;

[0054] FIG31 is a waveform diagram of a demodulated signal obtained by an ASK demodulation module in the related art;

[0055] Figure 32 is a waveform diagram of the demodulated signal obtained by the ASK demodulation module in an embodiment of the present application.

[0056] In the related art, the meanings of the reference numerals are as follows: 10, electronic device; 10A, wireless power receiving circuit; 110, second impedance compensation module; 120, rectifier module; 130, load; 140, ASK modulation module; 142, switch unit; 144, processing module; 150, FSK demodulation module;

[0057] The meanings of the reference numerals in the embodiments of the present application are as follows: 30, wireless power receiving circuit; 310, second impedance compensation module; 320, rectifier module; 330, impedance adjustment module; 332, first impedance unit; 334, switch unit; 336, second impedance unit; 340, processing module; 342, control unit; 344, modulation unit; 40, electronic device; 410, load;

[0058] The meanings of the various figure numbers used in the related art and the embodiments of the present application are: 20, wireless charging device; 210, power adapter; 220, charging stand; 220A, wireless power transmission circuit; 222, inverter module; 224, first impedance compensation module; 226, ASK demodulation module; 2262, filtering module; 2264, signal processing module; 228, FSK modulation module. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0060] It should be understood that the “multiple” mentioned in this application refers to two or more. In the description of this application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of this application, words such as “first” and “second” are used to distinguish between identical or similar items with basically the same functions and effects. Those skilled in the art can understand that words such as “first” and “second” do not limit the quantity and execution order, and words such as “first” and “second” do not necessarily limit them to be different.

[0061] Before explaining the wireless power receiving circuit provided in the embodiments of the present application in detail, the application scenarios and related technologies of the wireless power receiving circuit are first explained.

[0062] Wireless power transmission (WPT), also known as wireless power transmission, involves a power transmitter converting electrical energy into another form of relay energy. After transmitting the energy over a certain distance, a power receiver converts the relay energy back into electrical energy, thus achieving wireless power transmission. Depending on the form of relay energy used during the transmission process, wireless power transmission can be categorized as magnetic field coupling, electric field coupling, and electromagnetic field coupling.

[0063] With the development of wireless power transmission technology, more and more electronic devices are capable of wireless power transmission. For example, wireless charging devices can wirelessly charge electronic devices. In this process, the wireless charging device acts as a power transmitting device, such as a wireless charger, a mouse pad with integrated wireless charging function, a desk, a coffee table, a sofa, etc.; the electronic device acts as a power receiving device, such as a mobile phone, tablet computer, headphones, a bracelet, a watch, a stylus, a car, etc. For another example, a first electronic device can wirelessly charge a second electronic device. In this process, the first electronic device acts as a power transmitting device, such as a mobile phone, tablet computer, etc.; the second electronic device acts as a power receiving device, such as a mobile phone, tablet computer, headphones, a bracelet, a watch, a stylus, etc. Wireless charging technology is a magnetic field coupled wireless power transmission technology.

[0064] Taking the example of a wireless charging device 20 wirelessly charging an electronic device 10, where the electronic device 10 is a mobile phone, FIG1 is a schematic diagram of the appearance of the electronic device 10, and FIG2 is a schematic diagram of the appearance of the wireless charging device 20. As shown in FIG2, the wireless charging device 20 includes a power adapter 210 and a charging base 220 connected to the power adapter 210. When the power adapter 210 is connected to the mains, the power adapter 210 acts as a DC power supply, outputting DC power to the charging base 220. The charging base 220 is configured to convert the DC power output by the power adapter 210 into a varying magnetic field. FIG3 is a schematic diagram of a scenario in which the charging base 220 of the wireless charging device 20 wirelessly charges the electronic device 10. As shown in FIG1 to FIG3, when the electronic device 10 is placed on the charging base 220 of the wireless charging device 20, the electronic device 10 can convert the varying magnetic field generated by the charging base 220 into electrical energy, thereby achieving wireless charging of the electronic device 10.

[0065] It is understandable that in the embodiment shown in FIG3 , only a scenario is shown in which one wireless charging device 20 wirelessly charges one electronic device 10. In other embodiments, as shown in FIG4 , one wireless charging device 20 can also wirelessly charge multiple electronic devices 10 simultaneously.

[0066] The following uses the scenario shown in FIG3 as an example to illustrate the principle of power transmission in wireless charging technology.

[0067] Figure 5 is a circuit diagram of a wireless charging system. In the embodiment shown in Figure 5, the power adapter 210 is represented by a DC power supply Vd. That is, the DC power supply Vd is used to output DC power to the charging station 220. The charging station 220 is provided with a wireless power transmission circuit 220A. As shown in Figure 5, the wireless power transmission circuit 220A includes an inverter module 222, a first impedance compensation module 224, and a transmitting coil L1. The first input terminal of the inverter module 222 is connected to the positive terminal of the DC power supply Vd, and the second input terminal of the inverter module 222 is connected to the negative terminal of the DC power supply Vd. The first output terminal of the inverter module 222 is connected to the first terminal of the first impedance compensation module 224, and the second terminal of the first impedance compensation module 224 is connected to the first terminal of the transmitting coil L1. The second output terminal of the inverter module 222 is connected to the second terminal of the transmitting coil L1. Thus, when the wireless power transmission circuit 220A in the charging station 220 is in operation, the inverter module 222 can convert the DC power output by the DC power supply Vd into AC power of a preset frequency and output it to the transmitting coil L1. The first impedance compensation module 224 is used to compensate for the leakage inductance of the transmitter side, thereby achieving impedance matching of the circuit, thereby improving the transmission power of wireless charging. The transmitting coil L1 is used to convert alternating current into a changing magnetic field and transmit it into space.

[0068] The electronic device 10 is provided with a wireless power receiving circuit 10A and a load 130. As shown in FIG5 , the wireless power receiving circuit 10A includes a receiving coil L2, a second impedance compensation module 110, and a rectifier module 120. The receiving coil L2 is configured to perform electromagnetic induction with the transmitting coil L1. The first end of the receiving coil L2 is connected to the first end of the second impedance compensation module 110. The second end of the second impedance compensation module 110 is connected to the first input end of the rectifier module 120. The second end of the receiving coil L2 is connected to the second input end of the rectifier module 120. The output end of the rectifier module 120 is configured to connect to the load 130 of the electronic device 10. Thus, when the wireless power receiving circuit 10A is in operation, the receiving coil L2 can convert the changing magnetic field into alternating current (AC) and output it to the rectifier module 120. The rectifier module 120 can convert the input AC into DC and output it to the load 130, thereby supplying power to the load 130. The second impedance compensation module 110 is configured to compensate for leakage inductance on the receiving side, thereby achieving impedance matching in the circuit and improving the received power of wireless charging.

[0069] When the wireless charging device 20 wirelessly charges the electronic device 10, in addition to the transmission of electrical energy, communication is also required between the wireless charging device 20 and the electronic device 10. In other words, the wireless charging device 20 and the electronic device 10 need to transmit communication information to each other to ensure the reliability and safety of wireless charging. The communication information here is generally in the form of digital information. The content of the communication information may include the coupling degree between the transmitting coil L1 and the receiving coil L2, the identity document (ID) and type of the electronic device 10, the ID and type of the wireless charging device 20, the power required by the electronic device 10 and the boost information, etc.

[0070] Figure 6 is a circuit diagram of a wireless charging system for power transmission and communication in the related art. As shown in Figure 6, in the related art, the communication methods between the wireless charging device 20 and the electronic device 10 include: frequency shift keying (FSK) communication from the wireless charging device 20 to the electronic device 10; and amplitude shift keying (ASK) communication from the electronic device 10 to the wireless charging device 20. The FSK and ASK communication methods are described below.

[0071] The FSK communication method refers to the use of frequency changes in a carrier wave to transmit digital information. Based on this, the wireless power transmitting circuit 220A is also provided with an FSK modulation module 228. The FSK modulation module 228 is connected to the transmitting coil L1 and is used to modulate the frequency of the electrical signal in the transmitting coil L1 to represent binary 1 and 0. Due to the electromagnetic induction between the receiving coil L2 and the transmitting coil L1, the frequency change of the electrical signal in the transmitting coil L1 will also cause the frequency of the electrical signal in the receiving coil L2 to change. The wireless power receiving circuit 10A is also provided with an FSK demodulation module 150. The FSK demodulation module 150 is connected to the receiving coil L2 and demodulates the frequency of the electrical signal in the receiving coil L2 to obtain the digital information transmitted by the wireless charging device 20.

[0072] The ASK communication method uses changes in the amplitude of a carrier wave to transmit digital information. To this end, the wireless power receiving circuit 10A is also provided with an ASK modulation module 140. The ASK modulation module 140 is connected to the receiving coil L2 and is used to modulate the load in the wireless power receiving circuit 10A, thereby modulating the amplitude of the electrical signal in the receiving coil L2 to represent binary 1s and 0s. Due to electromagnetic induction between the receiving coil L2 and the transmitting coil L1, changes in the amplitude of the electrical signal in the receiving coil L2 will also cause changes in the amplitude of the electrical signal in the transmitting coil L1. The wireless power transmitting circuit 220A is also provided with an ASK demodulation module 226. The ASK demodulation module 226 is connected to the transmitting coil L1 and demodulates the amplitude of the electrical signal in the transmitting coil L1 to obtain the digital information transmitted by the electronic device 10.

[0073] The working principle of the ASK modulation module 140 is described below.

[0074] Figure 7 is a circuit diagram of a wireless charging system in the related art for power transmission and ASK modulation, which shows the circuit structure of the ASK modulation module 140, and does not show the FSK demodulation module 150, the ASK demodulation module 226, and the FSK modulation module 228. As shown in Figure 7, in the related art, the ASK modulation module 140 includes a first communication capacitor Ca, a second communication capacitor Cb, a switch unit 142, and a processing module 144. Among them, the first plate of the first communication capacitor Ca is connected to the first input end of the rectifier module 120, and the second plate of the first communication capacitor Ca is connected to the first end of the switch unit 142. The second end of the switch unit 142 is connected to the second plate of the second communication capacitor Cb, and the first plate of the second communication capacitor Cb is connected to the second input end of the rectifier module 120. The processing module 144 is connected to the control end of the switch unit 142 to control the conduction and disconnection between the first end and the second end of the switch unit 142. In this way, when the processing module 144 controls the first end and the second end of the switch unit 142 to be conductive, the branch where the first communication capacitor Ca and the second communication capacitor Cb are located is conductive. In this case, the circuit formed by the first communication capacitor Ca and the second communication capacitor Cb after being connected in series through the switch unit 142 is connected in parallel with the rectifier module 120, and the first communication capacitor Ca and the second communication capacitor Cb are connected to the wireless power receiving circuit 10A. When the processing module 144 controls the first end and the second end of the switch unit 142 to be disconnected, the branch where the first communication capacitor Ca and the second communication capacitor Cb are located is not conductive. In this case, the first communication capacitor Ca and the second communication capacitor Cb are not connected to the wireless power receiving circuit 10A. In this process, when the first communication capacitor Ca and the second communication capacitor Cb are switched between being connected and not connected to the wireless power receiving circuit 10A, it is equivalent to a change in the load size in the wireless power receiving circuit 10A, causing the amplitude of the electrical signal in the receiving coil L2 to change, thereby transmitting digital information to the wireless power transmitting circuit 220A.

[0075] Generally, as shown in FIG8 , in the ASK modulation module 140 , the switch unit 142 may include a transistor Q01 and a transistor Q02. The first electrode of the transistor Q01 is connected to the second plate of the first communication capacitor Ca, the second electrode of the transistor Q01 is connected to the second electrode of the transistor Q02, and the first electrode of the transistor Q02 is connected to the second plate of the second communication capacitor Cb. The processing module 144 is connected to the control electrode of the transistor Q01, the control electrode of the transistor Q02, the second electrode of the transistor Q01, and the second electrode of the transistor Q02, and is used to control the conduction and shutoff of the transistors Q01 and Q02. When the transistors Q01 and Q02 are turned on, the first and second terminals of the switch unit 142 are connected; when the transistors Q01 and Q02 are turned off, the first and second terminals of the switch unit 142 are disconnected.

[0076] The equivalent circuit of the circuit diagram shown in FIG7 is analyzed below.

[0077] Figure 9 is an equivalent circuit diagram of a wireless charging system in the related art when the switch unit 142 is turned off. Specifically, Figure 9 is an equivalent circuit diagram of the circuit diagram shown in Figure 7 when the switch unit 142 is turned off. The DC power supply Vd and the inverter module 222 are combined to simplify the AC power supply V1. In other words, the AC power supply V1 is used to output AC power of a preset frequency to the transmitting coil L1. Resistor R01 is the equivalent resistor in the wireless power transmitting circuit 220A. Capacitor C01 is the first impedance compensation module 224. Resistor R02 is the equivalent resistor in the wireless power receiving circuit 10A. Capacitor C02 is the second impedance compensation module 110. Load resistor RL is the equivalent resistance of the load 130 connected to the wireless power receiving circuit 10A. The second end of the transmitting coil L1 and the second end of the receiving coil L2 are both connected to the ground line GND.

[0078] As shown in Figure 9, when the switch unit 142 is off, the wireless power transmission circuit 220A can be equivalent to a circuit formed by the AC power source V1, resistor R01, capacitor C01, and transmitting coil L1 in series. The current in this circuit is the first current I1. The wireless power receiving circuit 10A and the load 130 in the electronic device 10 can be equivalent to a circuit formed by the receiving coil L2, resistor R02, capacitor C02, and load resistor RL in series. The current in this circuit is the second current I2.

[0079] Figure 10 is an equivalent circuit diagram of the wireless charging system when the switch unit 142 is turned on in the related art. Specifically, Figure 10 is an equivalent circuit diagram of the circuit diagram shown in Figure 7 when the switch unit 142 is turned on. Among them, capacitor C03 is a single-ended capacitor in the communication capacitor (including the first communication capacitor Ca and the second communication capacitor Cb). In other words, capacitor C03 is any one of the first communication capacitor Ca and the second communication capacitor Cb. Generally, the capacitance of the first communication capacitor Ca is equal to the capacitance of the second communication capacitor Cb.

[0080] As shown in Figure 10, when the switch unit 142 is turned on, the wireless power transmission circuit 220A is still equivalent to a circuit formed by the AC power supply V1, resistor R01, capacitor C01, and transmitting coil L1 in series. The current in this circuit is the first current I1. The wireless power receiving circuit 10A is equivalent to a circuit formed by the receiving coil L2, resistor R02, capacitor C02, and capacitor C03 in series. The load resistor RL and capacitor C03 are connected in parallel. In this circuit, the current in the main circuit is the second current I2, and the current in the load resistor RL is the third current I3. Therefore, the current in capacitor C03 is equal to the difference between the second current I2 and the third current I3.

[0081] Analyzing the equivalent circuit shown in Figure 10, we can obtain the following equation:

[0082] Where R1 is the impedance of resistor R01, C1 is the capacitance of capacitor C01, j is the 90-degree rotation factor, and w is the angular frequency of the current in the transmitting coil L1 and the receiving coil L2. is the capacitive reactance of capacitor C01, L1 is the inductance of transmitting coil L1, jwL1 is the inductive reactance of transmitting coil L1, I1 is the value of first current I1, M is the mutual inductance factor between transmitting coil L1 and receiving coil L2, I2 is the value of second current I2, U1 is the voltage of AC power supply V1, R2 is the impedance of resistor R02, C2 is the capacitance of capacitor C02, is the capacitive reactance of capacitor C02, L2 is the inductance of receiving coil L2, jwL2 is the inductive reactance of receiving coil L2, C3 is the capacitance of capacitor C03, is the capacitive reactance of capacitor C03, I3 is the value of the third current I3, R L is the impedance of the load resistor RL. Since the first current I1, the second current I2, and the third current I3 are all AC currents, the first current I1, the second current I2, and the third current I3 are all vectors. Since the voltage output by the AC power supply V1 is an AC voltage, the voltage of the AC power supply V1 is also a vector.

[0083] The above formula can be expressed in vector form as follows:

[0084] It can be seen that in the wireless charging system, when the system parameters are determined, the values ​​of the first current I1 , the second current I2 and the third current I3 can be obtained.

[0085] In the related art, when the wireless charging device 20 communicates with the electronic device 10, the communication capacitor will generate plate vibration. The reason is that the voltage on the communication capacitor is an alternating sinusoidal voltage, and the peak value of the voltage is proportional to the output voltage of the rectifier module 120. Therefore, when the power of wireless charging is high, the voltage output by the receiving coil L2 is large, the voltage output by the rectifier module 120 is also large, and the peak-to-peak value of the voltage on the communication capacitor is also large. In this case, the piezoelectric effect will cause the communication capacitor to generate a large plate vibration, thereby generating a large capacitor howling, affecting the user experience.

[0086] In the related art, in order to reduce the plate vibration of the communication capacitor, the generally adopted technical solution is to reduce the capacitance of the communication capacitor. However, as known from the above description, the working principle of the communication capacitor is that "the first communication capacitor Ca and the second communication capacitor Cb are equivalent to the change in the load size in the wireless power receiving circuit 10A when switching between connecting and not connecting to the wireless power receiving circuit 10A". Therefore, if the capacitance of the communication capacitor is reduced, the change in the load equivalent to the first communication capacitor Ca and the second communication capacitor Cb when switching between connecting and not connecting to the wireless power receiving circuit 10A will be reduced, thereby resulting in a decrease in the change in the amplitude of the electrical signal in the receiving coil L2, which is not conducive to the transmission of communication information and leads to a decrease in communication quality.

[0087] Based on this, embodiments of the present application provide a wireless power receiving circuit, electronic device, and wireless charging system. This wireless power receiving circuit can effectively address the problem of significant capacitive noise generated during wireless charging of electronic devices without reducing the capacitance of the communication capacitor, thereby improving the user experience.

[0088] The wireless power receiving circuit provided in the embodiment of the present application is explained and described in detail below. In the embodiment of the present application, the connection between two electronic devices / electrical modules refers to an electrical connection. The electrical connection here refers to a connection that can transmit electrical signals. Electrical connections include direct connections and indirect connections. For example, a direct connection between device A and device B means that device A and device B are connected by a wire to transmit electrical signals. An indirect connection between device A and device B means that device A is connected to the first end of device C by a wire, and the second end of device C is connected to device B by a wire, so that device A and device B can transmit electrical signals through device C. Electrical signals include current and voltage.

[0089] The wireless power receiving circuit is applied to electronic devices and can perform electromagnetic induction with the wireless power transmitting circuit in a wireless charging device and output direct current to the load in the electronic device, thereby realizing the wireless charging function of the electronic device. Figure 11 is a circuit structure diagram of a wireless power receiving circuit 30 provided in an embodiment of the present application. As shown in Figure 11, the wireless power receiving circuit 30 includes a receiving coil L2, a second impedance compensation module 310, a rectifier module 320, an impedance adjustment module 330, and a processing module 340.

[0090] The receiving coil L2 is coupled to the transmitting coil L1, enabling electrical energy transfer between the two coils via an alternating magnetic field. The receiving coil L2 receives the alternating magnetic field emitted by the transmitting coil L1 and converts it into alternating current for output. The receiving coil L2 can be a multi-turn planar coil or another type of coil, such as the magnetic bar coil in a stylus pen.

[0091] The first end of the second impedance compensation module 310 is connected to the first end of the receiving coil L2, and the second end of the second impedance compensation module 310 is connected to the first input end of the rectifier module 320. The second impedance compensation module 310 is used to compensate for leakage inductance on the receiving side, thereby achieving impedance matching in the circuit, thereby improving the received power of wireless charging. The second impedance compensation module 310 can be a capacitor or a high-order circuit formed by a capacitor and an inductor connected in series or in parallel.

[0092] The second input end of the rectifier module 320 is connected to the second end of the receiving coil L2. The output end of the rectifier module 320 is connected to the load 410 of the electronic device. Thus, when the wireless power receiving circuit 30 is in operation, the receiving coil L2 can output alternating current (AC) to the rectifier module 320 via the second impedance compensation module 310. The rectifier module 320 rectifies the AC power and outputs direct current (DC) to the load 410, thereby supplying power to the load 410. The rectifier module 320 can be a full-wave rectifier circuit or a half-wave rectifier circuit.

[0093] The first end of the impedance adjustment module 330 is connected to the first end of the second impedance compensation module 310, and the second end of the impedance adjustment module 330 is connected to the second end of the second impedance compensation module 310. In other words, the impedance adjustment module 330 and the second impedance compensation module 310 are connected in parallel. The processing module 340 is connected to the control end of the impedance adjustment module 330 and is used to control the conduction and shutdown of the impedance adjustment module 330. The conduction of the impedance adjustment module 330 means that there is electrical continuity between the first and second ends of the impedance adjustment module 330; the shutdown of the impedance adjustment module 330 means that there is no electrical continuity between the first and second ends of the impedance adjustment module 330.

[0094] When the wireless power receiving circuit 30 is operating, the impedance adjustment module 330 has two states: on and off. When the impedance adjustment module 330 is on, it is connected to the wireless power receiving circuit 30; when the impedance adjustment module 330 is off, it is disconnected from the wireless power receiving circuit 30. Therefore, when the impedance adjustment module 330 switches between being connected to and disconnected from the wireless power receiving circuit 30, it can be equivalent to a change in the load size in the wireless power receiving circuit 30, thereby changing the amplitude of the electrical signal in the receiving coil L2, thereby transmitting digital information to the wireless power transmitting circuit. In other words, by controlling the on and off states of the impedance adjustment module 330, the processing module 340 can perform ASK modulation on the waveform of the electrical signal in the receiving coil L2. In this wireless power receiving circuit 30, the communication capacitor connected in parallel with the rectifier module 320 is removed, which can avoid the problem of large plate vibration of the communication capacitor connected in parallel with the rectifier module 320, thereby generating large capacitor noise.

[0095] In some optional embodiments, the impedance adjustment module 330 may not include a communication capacitor, but may be composed of a communication resistor. In this case, since the communication capacitor is removed, the problem of the communication capacitor generating plate vibration, thereby generating a large capacitor howling, can be avoided. In other optional embodiments, the impedance adjustment module 330 may also include a communication capacitor. In this case, the communication capacitor is configured to be connected in parallel with the second impedance compensation module 310. Since in the series circuit formed by the receiving coil L2, the second impedance compensation module 310, and the rectifier module 320, the voltage of the second impedance compensation module 310 is much smaller than the voltage of the rectifier module 320. Therefore, the communication capacitor is configured to be connected in parallel with the second impedance compensation module 310, which can greatly reduce the voltage across the communication capacitor compared to the related art, thereby weakening the plate vibration of the communication capacitor, improving the problem of large capacitor howling when the electronic device is wirelessly charged, and thus improving the user experience.

[0096] It should be noted that in the above embodiment, for ease of understanding, the transmitting coil L1 and the load 410 are introduced to describe the connection method and operation process of the wireless power receiving circuit 30 provided in the embodiment of the present application. In fact, the wireless power receiving circuit 30 does not include the transmitting coil L1 and the load 410. In other words, the transmitting coil L1 and the load 410 exist as environmental elements relative to the wireless power receiving circuit 30 and should not be understood as limiting the wireless power receiving circuit 30 provided in the embodiment of the present application.

[0097] The circuit structure of each electrical module in the wireless power receiving circuit 30 is explained in detail below.

[0098] 1. Circuit structure of the impedance adjustment module 330.

[0099] 1. FIG12 is a circuit structure diagram of another wireless power receiving circuit 30 provided in an embodiment of the present application. As shown in FIG12 , in some embodiments, the impedance adjustment module 330 includes a first impedance unit 332 and a switch unit 334 .

[0100] The first impedance unit 332 can be an impedance device, such as a resistor or capacitor. The first impedance unit 332 can also be formed by multiple impedance devices connected in series or in parallel. The first end of the first impedance unit 332 is connected to the first end of the second impedance compensation module 310. The second end of the first impedance unit 332 is connected to the first end of the switch unit 334.

[0101] The switch unit 334 can be a three-terminal switch device. The switch unit 334 also has a second terminal and a control terminal. The control terminal of the switch unit 334 can control the conduction and disconnection between the first terminal and the second terminal of the switch unit 334. The second terminal of the switch unit 334 is connected to the second terminal of the second impedance compensation module 310. That is, in this embodiment, the first impedance unit 332 and the switch unit 334 are connected in series to form the impedance adjustment module 330.

[0102] The processing module 340 is connected to the control terminal of the switch unit 334. The processing module 340 is configured to control the on / off state of the switch unit 334, thereby controlling the on / off state of the impedance adjustment module 330. When the switch unit 334 is on, electrical conduction occurs between the first and second terminals of the switch unit 334; when the switch unit 334 is off, electrical conduction does not occur between the first and second terminals of the switch unit 334. In this embodiment, when the impedance adjustment module 330 is on, the switch unit 334 in the impedance adjustment module 330 is on; when the impedance adjustment module 330 is off, the switch unit 334 in the impedance adjustment module 330 is off.

[0103] The structures of the first impedance unit 332 and the switch unit 334 are described in detail below by taking the circuit structure shown in FIG. 12 as an example.

[0104] Figure 13 is a circuit diagram of a wireless power receiving circuit 30 provided in an embodiment of the present application, and the circuit diagram corresponds to the circuit structure shown in Figure 12. As shown in Figure 13, in some embodiments, the first impedance unit 332 includes a first capacitor C1. The first plate of the first capacitor C1 is connected to the first end of the second impedance compensation module 310, and the second plate of the first capacitor C1 is connected to the first end of the switch unit 334. In this embodiment, the first capacitor C1 can be the first communication capacitor Ca in the related art. In this case, the communication capacitor is set to be connected in parallel with the second impedance compensation module 310, which can greatly reduce the voltage across the communication capacitor compared to the related art, thereby weakening the plate vibration of the communication capacitor. In some other embodiments not shown, the impedance device in the first impedance unit 332 can also be a resistor.

[0105] As shown in Figure 13, in some embodiments, the switch unit 334 includes a first transistor Q1. The transistor here refers to a field effect transistor (FET), for example, a metal oxide semiconductor field effect transistor (MOSFET). The first electrode of the first transistor Q1 is connected to the second end of the first impedance unit 332. The second electrode of the first transistor Q1 is connected to the second end of the second impedance compensation module 310. The processing module 340 is connected to the control electrode of the first transistor Q1 and the second electrode of the first transistor Q1 to control the conduction and shutdown of the first transistor Q1 and the second transistor Q2. In some other embodiments not shown, the switch unit 334 can also be other three-terminal switching devices, such as a thyristor.

[0106] 2. In some other embodiments, based on the impedance adjustment module 330 including the first impedance unit 332 and the switch unit 334 , as shown in FIG14 , the impedance adjustment module 330 may further include a second impedance unit 336 .

[0107] The second impedance unit 336 can be a single impedance device, or it can be formed by multiple impedance devices connected in series or in parallel. Generally, the structure of the second impedance unit 336 is the same as that of the first impedance unit 332. Here, the first end of the second impedance unit 336 is connected to the second end of the switch unit 334, and the second end of the second impedance unit 336 is connected to the second end of the second impedance compensation module 310. In other words, the second end of the switch unit 334 is connected to the second end of the second impedance compensation module 310 through the second impedance unit 336. In this embodiment, the first impedance unit 332, the switch unit 334, and the second impedance unit 336 are connected in series to form the impedance adjustment module 330.

[0108] The structures of the first impedance unit 332 and the second impedance unit 336 are described in detail below by taking the circuit structure shown in FIG. 14 as an example.

[0109] FIG15 is a circuit diagram of another wireless power receiving circuit 30 provided in an embodiment of the present application, and the circuit diagram corresponds to the circuit structure shown in FIG14 . As shown in FIG15 , in some embodiments, the first impedance unit 332 includes a first capacitor C1. The first plate of the first capacitor C1 is connected to the first end of the second impedance compensation module 310, and the second plate of the first capacitor C1 is connected to the first end of the switch unit 334. The second impedance unit 336 includes a second capacitor C2. The second plate of the second capacitor C2 is connected to the second end of the switch unit 334, and the first plate of the second capacitor C2 is connected to the second end of the second impedance compensation module 310.

[0110] In this embodiment, the first capacitor C1 can be the first communication capacitor Ca in the related art, and the second capacitor C2 can be the second communication capacitor Cb in the related art. Based on this, the beneficial effects of this embodiment include: 1. The communication capacitor is set to be connected in parallel with the second impedance compensation module 310, which can greatly reduce the voltage across the communication capacitor compared to the related art, thereby weakening the plate vibration of the communication capacitor. 2. Compared with the related art, only the connection method of the first plate of the second communication capacitor Cb (i.e., the second capacitor C2 in this embodiment) changes, which is conducive to the implementation of the technical solution and is conducive to reducing the cost of electronic equipment.

[0111] FIG16 is a circuit diagram of another wireless power receiving circuit 30 provided in an embodiment of the present application, and the circuit diagram corresponds to the circuit structure shown in FIG14 . As shown in FIG16 , in other embodiments, the first impedance unit 332 includes a first resistor R1. The first end of the first resistor R1 is connected to the first end of the second impedance compensation module 310, and the second end of the first resistor R1 is connected to the first end of the switch unit 334. The second impedance unit 336 includes a second resistor R2. The second end of the second resistor R2 is connected to the second end of the switch unit 334, and the first end of the second resistor R2 is connected to the second end of the second impedance compensation module 310.

[0112] The structure of the switch unit 334 is described in detail below using the circuits shown in FIG. 15 and FIG. 16 .

[0113] As shown in Figures 15 and 16, in some embodiments, the switch unit 334 includes a first transistor Q1 and a second transistor Q2. The first electrode of the first transistor Q1 is connected to the second end of the first impedance unit 332. The second electrode of the first transistor Q1 is connected to the second electrode of the second transistor Q2. The first electrode of the second transistor Q2 is connected to the second end of the second impedance compensation module 310. In other words, the first transistor Q1 and the second transistor Q2 are connected in series to form the switch unit 334. The processing module 340 is connected to the control electrode of the first transistor Q1, the control electrode of the second transistor Q2, the second electrode of the first transistor Q1, and the second electrode of the second transistor Q2 to control the conduction and disconnection of the first transistor Q1 and the second transistor Q2.

[0114] In some specific embodiments, as shown in Figures 15 and 16, the first transistor Q1 and the second transistor Q2 are both N-type MOSFETs. The first electrode of the first transistor Q1 and the first electrode of the second transistor Q2 are both drains of the N-type transistors. The second electrode of the first transistor Q1 and the second electrode of the second transistor Q2 are both sources of the N-type transistors. In this case, the processing module 340 may have a first port and a second port. The first port of the processing module 340 is connected to the control electrodes of the first transistor Q1 and the second transistor Q2, and the second port of the processing module 340 is connected to the second electrodes of the first transistor Q1 and the second transistor Q2. When the processing module 340 needs to control the switch unit 334 to conduct, the first port of the processing module 340 may output a high-level signal and the second port of the processing module 340 may output a low-level signal, so that the difference between the gate voltage and the source voltage of the first transistor Q1 is greater than the threshold voltage of the first transistor Q1, and the difference between the gate voltage and the source voltage of the second transistor Q2 is greater than the threshold voltage of the second transistor Q2. In this way, both the first transistor Q1 and the second transistor Q2 are turned on. When the processing module 340 needs to control the switch module to turn off, the first port of the processing module 340 may output a low-level signal, and the second port of the processing module 340 may output a high-level signal, so that the difference between the gate voltage and the source voltage of the first transistor Q1 is less than the threshold voltage of the first transistor Q1, and the difference between the gate voltage and the source voltage of the second transistor Q2 is less than the threshold voltage of the second transistor Q2. In this way, both the first transistor Q1 and the second transistor Q2 are turned off. In other embodiments not shown, the first transistor Q1 and the second transistor Q2 may also be P-type MOSFETs, which will not be described in detail.

[0115] 2. Circuit structure of the processing module 340.

[0116] FIG17 is a circuit diagram of another wireless power receiving circuit 30 provided in an embodiment of the present application. As shown in FIG17 , in some embodiments, the processing module 340 includes a control unit 342 and a modulation unit 344 .

[0117] Control unit 342 can be a microcontroller unit (MCU), i.e., a single-chip microcomputer (SCM). The output of control unit 342 is connected to the input of modulation unit 344. Control unit 342 is configured to generate a control signal based on the communication information and transmit the control signal to modulation unit 344. The communication information can be pre-stored by control unit 342 or transmitted to control unit 342 by a system on chip (SOC) in the electronic device.

[0118] The output terminal of the modulation unit 344 is connected to the control terminal of the impedance adjustment module 330. The modulation unit 344 is used to modulate the control signal to generate a modulation signal. The modulation signal is used to control the conduction and shutdown of the impedance adjustment module 330.

[0119] Specifically, when the electronic device used by the wireless power receiving circuit 30 approaches the wireless charging device, the transmitting coil L1 will begin to output an electrical signal based on electromagnetic induction. The control unit 342 can detect whether the transmitting coil L1 outputs an electrical signal, and when the control unit 342 detects that the transmitting coil L1 starts to output an electrical signal, it can generate a control signal based on the communication information. The communication information here can be, for example, the coupling degree between the transmitting coil L1 and the receiving coil L2 detected by the control unit 342, the ID of the electronic device, etc. The control signal is output to the modulation unit 344. After receiving the control signal, the modulation unit 344 modulates the control signal to generate a modulation signal.

[0120] It is understood that when both the first transistor Q1 and the second transistor Q2 are N-type MOSFETs, the output end of the modulation unit 344 may include a first port and a second port. The first port of the modulation unit 344 is connected to the control electrode of the first transistor Q1 and the control electrode of the second transistor Q2. In other words, the first port of the modulation unit 344 is the first port of the processing module 340. The second port of the modulation unit 344 is connected to the second electrode of the first transistor Q1 and the second electrode of the second transistor Q2. In other words, the second port of the modulation unit 344 is the second port of the processing module 340.

[0121] 3. Circuit structure of the second impedance compensation module 310.

[0122] Figure 18 is a circuit diagram of another wireless power receiving circuit 30 provided in an embodiment of the present application. As shown in Figure 18, in some embodiments, the second impedance compensation module 310 includes a third capacitor C3. The first plate of the third capacitor C3 is connected to the first end of the receiving coil L2 and the first end of the impedance adjustment module 330. The second plate of the third capacitor C3 is connected to the first input end of the rectifier module 320 and the second end of the impedance adjustment module 330.

[0123] Furthermore, as shown in FIG19 , in some other embodiments, the second impedance compensation module 310 may further include a fourth capacitor C4 and an inductor L3 .

[0124] The second plate of the third capacitor C3 is connected to the first plate of the fourth capacitor C4 and the first end of the inductor L3. The second end of the inductor L3 is connected to the first input end of the rectifier module 320 and the second end of the impedance adjustment module 330. In other words, the second plate of the third capacitor C3 is connected to the first input end of the rectifier module 320 and the second end of the impedance adjustment module 330 via the inductor L3. The second plate of the fourth capacitor C4 is connected to the second end of the receiving coil L2. In other embodiments, the second plate of the fourth capacitor C4 may also be connected to the ground wire.

[0125] 4. Circuit structure of the rectifier module 320.

[0126] In the embodiment of the present application, the rectifier module 320 can be a full-wave rectifier circuit or a half-wave rectifier circuit, which will be described below.

[0127] Figure 20 is a circuit diagram of a rectifier module 320 provided in an embodiment of the present application. As shown in Figure 20 , in some embodiments, the rectifier module 320 is a full-wave rectifier circuit. In this case, the rectifier module 320 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

[0128] The cathode of the first diode D1 is connected to the anode of the second diode D2. The anode of the first diode D1 is connected to the anode of the third diode D3. The cathode of the third diode D3 is connected to the anode of the fourth diode D4. The cathode of the fourth diode D4 is connected to the cathode of the second diode D2. Here, the anode of the second diode D2 serves as the first input terminal of the rectifier module 320 and is connected to the second terminal of the impedance compensation module. The anode of the fourth diode D4 serves as the second input terminal of the rectifier module 320 and is connected to the second terminal of the receiving coil L2. The cathodes of the second diode D2 and the fourth diode D4 are connected to the positive electrode of the load 410, while the anodes of the first diode D1 and the third diode D3 are connected to the negative electrode of the load 410.

[0129] When the rectifier module 320 is operating, if current flows out of the first end of the receiving coil L2, the current can flow into the second end of the receiving coil L2 through the second diode D2, the positive electrode of the load 410, the negative electrode of the load 410, and the third diode D3 in sequence. If current flows out of the second end of the receiving coil L2, the current can flow into the first end of the receiving coil L2 through the fourth diode D4, the positive electrode of the load 410, the negative electrode of the load 410, and the first diode D1 in sequence.

[0130] It is understandable that in some other embodiments, the first diode D1 , the second diode D2 , the third diode D3 , and the fourth diode D4 may also be replaced by MOSFETs.

[0131] FIG21 is a circuit diagram of another rectifier module 320 provided in an embodiment of the present application. As shown in FIG21 , in other embodiments, the rectifier module 320 is a half-wave rectifier circuit. In this case, the rectifier module 320 includes a fifth diode D5 and a sixth diode D6.

[0132] The anode of the fifth diode D5 is connected to the first input terminal of the rectifier module 320 and the second terminal of the impedance compensation module. The cathode of the sixth diode D6 is connected to the second terminal of the receiving coil L2. The cathode of the fifth diode D5 is connected to the positive electrode of the load 410, and the anode of the sixth diode D6 is connected to the negative electrode of the load 410.

[0133] When the rectifier module 320 is operating, if current flows out of the first end of the receiving coil L2, the current can flow into the second end of the receiving coil L2 through the fifth diode D5, the positive electrode of the load 410, the negative electrode of the load 410, and the sixth diode D6. If current flows out of the second end of the receiving coil L2, the current cannot flow into the load 410 due to the unidirectional conduction of the diode.

[0134] It is understandable that in some other embodiments, the rectifier module 320 may include only one of the fifth diode D5 and the sixth diode D6. The fifth diode D5 and the sixth diode D6 may also be replaced by transistors.

[0135] The present application also provides an electronic device. The electronic device includes a load 410 and the wireless power receiving circuit 30 of any of the above embodiments. The output end of the wireless power receiving circuit 30 is connected to the load 410 and is configured to output an electrical signal to the load 410. Here, the output end of the wireless power receiving circuit 30 refers to the output end of the rectifier module 320.

[0136] Load 410 refers to an electrical device in an electronic device. In some embodiments, load 410 includes, but is not limited to, at least one of: an energy storage module for storing electrical energy, a memory for data storage, a radio frequency module for wireless communication, a Bluetooth module, a system-on-chip (SOC), a display screen, a speaker, a microphone, a camera, a motor, and sensors (e.g., a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a temperature sensor, an ambient light sensor, a bone conduction sensor, etc.). The SOC includes a central processing unit (CPU), a graphics processing unit (GPU), a baseband processor, etc. Memory includes internal memory and external memory. A voltage conversion circuit may also be connected between the wireless power receiving circuit 30 and the load 410. The voltage conversion circuit may be a step-down (buck) circuit or a step-up (boost) circuit.

[0137] An embodiment of the present application also provides a wireless charging system. The wireless charging system includes a wireless charging device and an electronic device. The wireless charging device is used to wirelessly charge the electronic device. The wireless charging device includes a power adapter and a charging base. The charging base is provided with a wireless power transmission circuit. When the wireless charging device is in operation, the power adapter is used to output direct current (DC) power to the wireless power transmission circuit.

[0138] FIG22 is a circuit diagram of a wireless charging system for power transmission and ASK modulation, provided in an embodiment of the present application, in which a DC power supply Vd represents a power adapter. As shown in FIG22 , a wireless power transmission circuit 220A includes an inverter module 222, a first impedance compensation module 224, and a transmitting coil L1; an electronic device 40 includes a load 410 and a wireless power receiving circuit 30 according to any of the above-described embodiments, which will not be described in detail. In an embodiment of the present application, the wireless power receiving circuit 30 includes a receiving coil L2, a second impedance compensation module 310, a rectifier module 320, an impedance adjustment module 330, and a processing module 340. By controlling the on and off state of the impedance adjustment module 330, the processing module 340 performs ASK modulation on the waveform of the electrical signal in the receiving coil L2, thereby transmitting communication information to the wireless power transmission circuit 220A.

[0139] The circuit structure of each electrical module in the wireless power transmitting circuit 220A is explained in detail below.

[0140] 1. Structure of transmitting coil L1.

[0141] The transmitting coil L1 is used to convert alternating current into an alternating magnetic field and transmit it into space. The transmitting coil L1 can be a multi-turn planar coil or a coil of other shapes, such as a magnetic bar coil in a tablet computer.

[0142] 2. Circuit structure of the first impedance compensation module 224.

[0143] The circuit structure of the first impedance compensation module 224 is generally the same as that of the second impedance compensation module 310. As shown in Figure 22, when the second impedance compensation module 310 includes only the third capacitor C3, the first impedance compensation module 224 may include only the fifth capacitor C5. The first plate of the fifth capacitor C5 is connected to the first output terminal of the inverter module 222, and the second plate of the fifth capacitor C5 is connected to the first end of the transmitting coil L1. The capacitance of the fifth capacitor C5 may be different from that of the third capacitor C3. In some other embodiments, the first impedance compensation module 224 may also be a high-order circuit formed by capacitors and inductors connected in series or in parallel. Here, the first impedance compensation module 224 can be used to compensate for the leakage inductance of the transmitting side and achieve impedance matching on the transmitting side, thereby increasing the wireless charging power, improving the wireless charging phase, and thereby increasing the wireless charging gain.

[0144] 3. Circuit structure of the inverter module 222.

[0145] In the embodiment of the present application, the inverter module 222 can be a full-wave inverter circuit or a half-wave inverter circuit, which will be described below.

[0146] Figure 23 is a circuit diagram of an inverter module 222 provided in an embodiment of the present application. As shown in Figure 23 , in some embodiments, the inverter module 222 is a full-wave inverter circuit. In this case, the rectifier module 320 includes a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, and a sixth transistor Q6.

[0147] The third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6 are all N-type MOSFETs. The first electrode (drain) of the third transistor Q3 and the first electrode of the fourth transistor Q4 are both connected to the positive electrode of the DC power supply Vd. The second electrode (source) of the third transistor Q3 is connected to the first electrode of the fifth transistor Q5. The second electrode of the fourth transistor Q4 is connected to the first electrode of the sixth transistor Q6. The second electrode of the fifth transistor Q5 and the second electrode of the sixth transistor Q6 are both connected to the negative electrode of the DC power supply Vd. Here, the node formed by the connection of the first electrode of the third transistor Q3 and the first electrode of the fourth transistor Q4 serves as the first input terminal of the inverter module 222. The node formed by the connection of the second electrode of the fifth transistor Q5 and the second electrode of the sixth transistor Q6 serves as the second input terminal of the inverter module 222. The node formed by the connection of the second electrode of the third transistor Q3 and the first electrode of the fifth transistor Q5 serves as the first output terminal of the inverter module 222, which is connected to the first terminal of the first impedance compensation module 224. A node formed by connecting the second electrode of the fourth transistor Q4 and the first electrode of the sixth transistor Q6 serves as a second output terminal of the inverter module 222 , and is configured to be connected to the second end of the transmitting coil L1 .

[0148] When the inverter module 222 is operating, it outputs alternating current (AC). A cycle of the AC power consists of a first half-cycle and a second half-cycle. During the first half-cycle, the third transistor Q3 and the sixth transistor Q6 are closed, while the fourth transistor Q4 and the fifth transistor Q5 are closed. This allows current to flow from the positive electrode of the DC power supply Vd, sequentially through the third transistor Q3, the first impedance compensation module 224, the first and second terminals of the transmitting coil L1, and the sixth transistor Q6, into the negative electrode of the DC power supply Vd. During the second half-cycle, the third transistor Q3 and the sixth transistor Q6 are closed, while the fourth transistor Q4 and the fifth transistor Q5 are closed. This allows current to flow from the positive electrode of the DC power supply Vd, sequentially through the fourth transistor Q4, the second and first terminals of the transmitting coil L1, the first impedance compensation module 224, and the fifth transistor Q5, into the negative electrode of the DC power supply Vd. During this process, the frequency of the AC power output by the inverter module 222 can be controlled by controlling the operating frequencies of the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6.

[0149] Figure 24 is a circuit diagram of another inverter module 222 provided in an embodiment of the present application. As shown in Figure 24, in other embodiments, the inverter module 222 is a half-wave inverter circuit. In this case, the inverter module 222 includes a seventh transistor Q7, an eighth transistor Q8, a sixth capacitor C6, and a seventh capacitor C7.

[0150] The seventh transistor Q7 and the eighth transistor Q8 are both N-type MOSFETs. The first plate of the sixth capacitor C6 and the first electrode of the seventh transistor Q7 are both connected to the positive electrode of the DC power supply Vd. The second plate of the sixth capacitor C6 is connected to the first plate of the seventh capacitor C7. The second electrode of the seventh transistor Q7 is connected to the first electrode of the eighth transistor Q8. The second plate of the seventh capacitor C7 and the second electrode of the eighth transistor Q8 are both connected to the negative electrode of the DC power supply Vd. Here, the node formed by the connection of the first plate of the sixth capacitor C6 and the first electrode of the seventh transistor Q7 serves as the first input terminal of the inverter module 222. The node formed by the connection of the second plate of the seventh capacitor C7 and the second electrode of the eighth transistor Q8 serves as the second input terminal of the inverter module 222. The node formed by the connection of the second electrode of the seventh transistor Q7 and the first electrode of the eighth transistor Q8 serves as the first output terminal of the inverter module 222, which is connected to the first terminal of the first impedance compensation module 224. The node formed by the connection of the second plate of the sixth capacitor C6 and the first plate of the seventh capacitor C7 serves as the second output terminal of the inverter module 222, which is connected to the second terminal of the transmitting coil L1.

[0151] When the inverter module 222 is operating, it outputs alternating current (AC). A cycle of the AC power includes a first half-cycle and a second half-cycle. During the first half-cycle, the seventh transistor Q7 is closed and the eighth transistor Q8 is closed. Consequently, current can flow from the first plate of the sixth capacitor C6 and flow sequentially through the seventh transistor Q7, the first impedance compensation module 224, the first end, and the second end of the transmitting coil L1 into the second plate of the sixth capacitor C6. During the second half-cycle, the seventh transistor Q7 is closed and the eighth transistor Q8 is closed. Consequently, current can flow from the first plate of the seventh capacitor C7 and flow sequentially through the second end, the first end, the first impedance compensation module 224, and the eighth transistor Q8 into the second plate of the seventh capacitor C7.

[0152] 4. Circuit structure of the ASK demodulation module 226.

[0153] FIG25 is a circuit diagram of a wireless charging system for power transmission and ASK communication according to an embodiment of the present application. As shown in FIG25 , in order to implement ASK communication, the ASK demodulation module 226 may include a filtering module 2262 and a signal processing module 2264 .

[0154] Generally, when the wireless charging system is working, the frequency of ASK communication is lower than the operating frequency of wireless charging. For example, in some specific embodiments, the operating frequency of wireless charging is about 130KHz (kilohertz), while the frequency of ASK communication is about 2KHz. Based on this, the filtering module 2262 can be arranged between the transmitting coil L1 and the signal processing module 2264. Among them, the filtering module 2262 is used to filter out the electrical signal of wireless charging (i.e., the electrical signal with a frequency of 130KHz) and only retain the electrical signal of ASK communication (i.e., the electrical signal with a frequency of 2KHz). The filtering module 2262 can be a low-pass filter circuit or a band-pass filter circuit. For example, in the embodiment shown in Figure 25, the filtering module 2262 is a low-pass filter circuit formed by connecting the eighth capacitor C8 and the third resistor R3. Among them, the first plate of the eighth capacitor C8 is connected to the first end of the transmitting coil L1, and the second plate of the eighth capacitor C8 is connected to the signal processing module 2264. The first end of the third resistor R3 is connected to the first plate of the eighth capacitor C8, and the second end of the third resistor R3 is connected to the ground line GND. The voltage of the ground line GND is generally equal to the voltage of the negative electrode of the DC power supply Vd. The signal processing module 2264 is used to process the ASK communication signal to obtain the communication information transmitted by the electronic device 40.

[0155] The following takes the wireless charging system shown in Figures 22 and 25 as an example and compares it with related technologies to analyze in detail the beneficial effects brought about by the wireless power receiving circuit 30 provided in the embodiment of the present application when applied to the electronic device 40.

[0156] In the related art, as mentioned above, the voltage on the communication capacitor is an alternating sinusoidal voltage, and the peak-to-peak value of the voltage is proportional to the output voltage of the rectifier module 320. Specifically:

[0157] Among them, V pp is the peak-to-peak value of the voltage on the communication capacitor, V p is the peak value of the voltage on the communication capacitor, V out is the output voltage of the rectifier module 320.

[0158] In this case, when the output power of the rectifier module 320 is 50 W (watts), the output voltage is 20 V (volts), and the output current is 2.5 A (amperes), the peak-to-peak voltage on the communication capacitor is approximately 51 V. The larger the capacitance of the communication capacitor, the more pronounced the piezoelectric effect and the greater the plate vibration.

[0159] In order to more intuitively observe the peak-to-peak value of the voltage on the communication capacitor in the embodiment of the present application, the equivalent circuit diagram of the wireless charging system in the embodiment of the present application is analyzed below.

[0160] Figure 26 is an equivalent circuit diagram of a wireless charging system provided by an embodiment of the present application when the switch unit 334 is turned off. Specifically, Figure 26 is an equivalent circuit diagram of the circuit diagram shown in Figure 22 when the switch unit 334 is turned off. In this case, the DC power supply Vd and the inverter module 222 are combined and simplified into an AC power supply V1. Resistor Ra is the equivalent resistance in the wireless power transmitting circuit 220A. Resistor Rb is the equivalent resistance in the wireless power receiving circuit 30. Load resistor RL is the equivalent resistance of the load 410 connected to the wireless power receiving circuit 30. The second end of the transmitting coil L1 and the second end of the receiving coil L2 are both connected to the ground line GND. According to Figure 26 and Figure 9, when the switch unit 334 is turned off, the equivalent circuit of the wireless charging system provided by the embodiment of the present application is the same as the equivalent circuit of the wireless charging system in the related art.

[0161] FIG27 is an equivalent circuit diagram of a wireless charging system provided by an embodiment of the present application when the switch unit 334 is turned on. Specifically, FIG27 is an equivalent circuit diagram of the circuit diagram shown in FIG22 when the switch unit 334 is turned on. Capacitor C0 is a single-ended capacitor in the communication capacitor (including the first capacitor C1 and the second capacitor C2). In other words, capacitor C0 is any one of the first capacitor C1 and the second capacitor C2. Generally, the capacitance of the first capacitor C1 is equal to the capacitance of the second capacitor C2.

[0162] The above equivalent circuit is analyzed with the electronic device 40 being a mobile phone and the wireless charging device 20 being a wireless charger. The inductance of the transmitting coil L1 is 12 μH (microhenry), the inductance of the receiving coil L2 is 4.8 μH, the capacitance of the fifth capacitor C5 is 247 nF (nanofarad), the capacitance of the third capacitor C3 is 990 nF, the coupling coefficient between the transmitting coil L1 and the receiving coil L2 is 0.73, the resistance of the resistor Ra is 200 mΩ (milliohm), the resistance of the resistor Rb is 300 mΩ, and the resistance of the load resistor RL is 6.5 Ω. When the switch unit 334 is turned on, it is equivalent to adding a capacitor C0 to the circuit. Since the capacitor C0 is connected in parallel with the third capacitor C3, the increase in the capacitor C0 can be regarded as an increase in the capacitance of the third capacitor C3. Based on this, with the capacitance of the third capacitor C3 as a variable, the voltage across the third capacitor C3 is measured as a function of the capacitance of the third capacitor C3, as shown in FIG. 28. In FIG28 , the horizontal axis is the capacitance of the third capacitor C3, and the unit is 10 -6F; the ordinate is the voltage across the third capacitor C3, in V. According to Figure 28, when the capacitance of the third capacitor C3 increases from 1000nF to 2000nF, the voltage across it gradually decreases. When the capacitance of the third capacitor C3 is minimum (the capacitance of the third capacitor C3 is 1000nF, which is equivalent to the switch unit 334 being turned off and the capacitor C0 being cut out), the voltage across the third capacitor C3 is also around 5V (about 5.3V). In other words, the peak value of the voltage across the third capacitor C3 is around 5V, about 5.3V, i.e., the peak-to-peak value of the voltage across the third capacitor C3 is around 10V, about 10.6V. The voltage across capacitor C0 is equal to the voltage across the third capacitor C3. It can be seen that in the embodiment of the present application, the peak-to-peak value of the voltage on the communication capacitor (about 10.6V) is much smaller than the peak-to-peak value of the voltage on the communication capacitor in the related art (about 51V), thereby solving the plate vibration problem of the communication capacitor.

[0163] Next, a simulation circuit is built using simulation software to compare and observe the voltage and current at various positions of the wireless charging system in the related art and the embodiment of the present application.

[0164] In the simulation circuit of the wireless charging system in the related art, the capacitance of the first communication capacitor Ca and the second communication capacitor Cb are both 69nF. The first communication capacitor Ca and the second communication capacitor Cb are each formed by a 47nF capacitor and a 22nF capacitor connected in parallel.

[0165] The electrical signal waveforms at various positions of the simulation circuit of the wireless charging system in the related art are shown in Figure 29. In Figure 29, the eight electrical signal waveforms from top to bottom along the paper are: the voltage waveform of the modulation signal, the voltage waveform of the capacitor C03 (communication capacitor), the voltage waveform of the capacitor C02 (second impedance compensation module 310), the voltage waveform of the AC power supply V1, the voltage waveform on the transmitting coil L1, the voltage waveform received by the signal processing module, the current waveform on the receiving coil L2, and the current waveform on the transmitting coil L1. Among them, in the vertical axis direction, the voltage unit is V and the current unit is A. According to Figure 29, in the related art, the peak value of the voltage across the capacitor C03 as the communication capacitor is about 26V, and the peak-to-peak value is about 52V, which is basically the same as the above analysis. In addition, in the related art, the voltage across the capacitor C02 as the impedance compensation module on the receiving side is about 5.5V, and the peak-to-peak value is about 11V. When switch unit 142 is turned on (i.e., when the modulation signal level changes), the voltage waveform of AC power supply V1 remains essentially unchanged, while the voltage on transmitting coil L1 changes significantly. The signal processing module is able to receive the waveform of the significantly changing electrical signal. As the voltage on transmitting coil L1 changes, the current on receiving coil L2 remains essentially unchanged, while the current on transmitting coil L1 changes significantly. Furthermore, according to simulation results, in related art, the input power of the wireless charging system is approximately 56W, the output power is approximately 49.9W, and the system efficiency is approximately 89%.

[0166] In the simulation circuit of the wireless charging system provided in the embodiment of the present application, the capacitance of the first capacitor C1 and the second capacitor C2 is also 69nF, and the first capacitor C1 and the second capacitor C2 are each formed by a 47nF capacitor and a 22nF capacitor connected in parallel. The third capacitor C3 is 990nF. In other words, when the switch unit 334 is turned on, the third capacitor C3 is equivalent to changing from 990nF to 1059nF.

[0167] The electrical signal waveforms at various positions of the simulation circuit of the wireless charging system in the embodiment of the present application are shown in Figure 30. In Figure 30, the eight electrical signal waveforms from top to bottom along the paper are: the voltage waveform of the modulation signal, the voltage waveform of the capacitor C0 (communication capacitor), the voltage waveform of the third capacitor C3 (second impedance compensation module 310), the voltage waveform of the AC power supply V1, the voltage waveform on the transmitting coil L1, the voltage waveform received by the signal processing module 2264, the current waveform on the receiving coil L2, and the current waveform on the transmitting coil L1. Wherein, in the vertical axis direction, the voltage unit is V and the current unit is A. According to Figure 30, in the embodiment of the present application, the peak-to-peak value of the voltage across the capacitor C0 as the communication capacitor is about 9.27V, and the peak value of the voltage across the third capacitor C3 as the impedance compensation module on the receiving side is about 9.9V, which is basically the same as the above analysis. Wherein, the voltage of the capacitor C0 is slightly smaller than the voltage of the third capacitor C3 because there is a certain voltage on the first transistor Q1 and the second transistor Q2. Based on this, the embodiment of the present application can effectively reduce the plate vibration of the communication capacitor. In addition, in the embodiment of the present application, when the modulation signal level changes, the signal processing module 2264 can receive the waveform of the electrical signal that changes significantly. When the modulation signal level changes, the voltage waveform of the AC power supply V1, the voltage waveform on the transmitting coil L1, the current waveform on the receiving coil L2, and the current waveform on the transmitting coil L1 are all basically unchanged. In addition, according to the simulation results, in the embodiment of the present application, the input power of the wireless charging system is approximately 59W, the output power is approximately 54W, and the system efficiency is approximately 91%. It can be seen that the charging power of the wireless charging system has also been improved to a certain extent.

[0168] Finally, through experiments, the ASK communication capabilities of the wireless charging system in the related technology and the embodiment of the present application are compared.

[0169] In the related art, when the wireless charging system performs ASK communication, the waveform of the demodulated signal obtained by the ASK demodulation module 226 is shown in Figure 31. As shown in Figure 31, in the related art, when performing ASK communication, the maximum voltage value of the demodulated signal obtained by the ASK demodulation module 226 is 189.66mV, the minimum voltage value is -210.34mV, and the voltage difference between the maximum and minimum voltage values ​​is 400mV, which ensures ASK communication.

[0170] In the embodiment of the present application, when the wireless charging system performs ASK communication, the waveform of the demodulated signal obtained by the ASK demodulation module 226 is shown in Figure 32. As can be seen from Figure 32, in the embodiment of the present application, when performing ASK communication, the maximum voltage value of the demodulated signal obtained by the ASK demodulation module 226 is 657.04mV, the minimum voltage value is -441.36mV, and the voltage difference between the maximum voltage value and the minimum voltage value is approximately 1098mV, which is greater than the 400mV in the related art. This shows that the ASK communication sent by the electronic device 40 can be correctly recognized by the ASK demodulation module 226 in the wireless charging device 20.

[0171] The wireless power receiving circuit 30 provided in the embodiments of the present application has at least the following beneficial effects: 1. In this wireless power receiving circuit 30, the communication capacitor connected in parallel with the rectifier module 320 is removed, thereby avoiding the problem of large plate vibration of the communication capacitor connected in parallel with the rectifier module 320, which can cause large capacitor noise. 2. The impedance adjustment module 330 can be composed of a communication resistor instead of a communication capacitor. In this case, since the communication capacitor is removed, the plate vibration of the communication capacitor can be avoided. 3. The impedance adjustment module 330 can also include a communication capacitor. In this case, the communication capacitor is arranged in parallel with the second impedance compensation module 310. Because the voltage of the second impedance compensation module 310 is much lower than the voltage of the rectifier module 320 in the series circuit formed by the receiving coil L2, the second impedance compensation module 310, and the rectifier module 320, the communication capacitor is arranged in parallel with the second impedance compensation module 310. Therefore, compared with the related art, the voltage across the communication capacitor can be greatly reduced, thereby reducing the plate vibration of the communication capacitor, improving the problem of large capacitor noise generated when the electronic device 40 is wirelessly charged, and thus improving the user experience. In addition, the control logic of the switch unit 334 by the processing module 340 does not need to change, making the solution more feasible. 4. This solution can be obtained by changing the connection method of the first plate of the second communication capacitor Cb in the related art, which is conducive to the implementation of the technical solution and is conducive to reducing the cost of the electronic device 40. 5. Since the voltage of the communication capacitor is reduced, the communication capacitor can use a capacitor with a slightly lower withstand voltage, and the optional range of the capacitor value and the cost are optimized. 6. It can improve the efficiency of wireless charging.

[0172] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A wireless power receiving circuit, applied to electronic equipment, characterized in that: The wireless power receiving circuit includes: a receiving coil, an impedance compensation module, a rectification module, an impedance adjustment module and a processing module; The first end of the receiving coil is connected to the first end of the impedance compensation module, the second end of the impedance compensation module is connected to the first input end of the rectifier module, the second end of the receiving coil is connected to the second input end of the rectifier module, and the output end of the rectifier module is used to connect to the load of the electronic device; The first end of the impedance adjustment module is connected to the first end of the impedance compensation module, and the second end of the impedance adjustment module is connected to the second end of the impedance compensation module; The processing module is connected to the control end of the impedance adjustment module, and the processing module is used to control the conduction and shutdown of the impedance adjustment module to change the waveform of the electrical signal in the receiving coil. The change in the waveform of the electrical signal in the receiving coil is used to transmit communication information.

2. The wireless power receiving circuit according to claim 1, wherein: The impedance adjustment module includes: a first impedance unit and a switch unit; The first end of the first impedance unit is connected to the first end of the impedance compensation module, the second end of the first impedance unit is connected to the first end of the switch unit, and the second end of the switch unit is connected to the second end of the impedance compensation module; The processing module is connected to the control end of the switch unit, and is used to control the on and off of the switch unit to control the on and off of the impedance adjustment module.

3. The wireless power receiving circuit according to claim 2, wherein: The impedance adjustment module further includes: a second impedance unit; The first end of the second impedance unit is connected to the second end of the switch unit, and the second end of the second impedance unit is connected to the second end of the impedance compensation module.

4. The wireless power receiving circuit according to claim 3, wherein: The first impedance unit includes a first capacitor, and the second impedance unit includes a second capacitor; or / and, The first impedance unit includes a first resistor, and the second impedance unit includes a second resistor.

5. The wireless power receiving circuit according to any one of claims 2 to 4, wherein: The switch unit includes: a first transistor and a second transistor; The first electrode of the first transistor is connected to the second end of the first impedance unit, the second electrode of the first transistor is connected to the second electrode of the second transistor, and the first electrode of the second transistor is connected to the second end of the impedance compensation module; The processing module is connected to the control electrode of the first transistor, the control electrode of the second transistor, the second electrode of the first transistor, and the second electrode of the second transistor to control the on and off of the first transistor and the second transistor.

6. The wireless power receiving circuit according to claim 5, wherein: The first transistor and the second transistor are both N-type transistors, the first electrode of the first transistor and the first electrode of the second transistor are both drains of the N-type transistors, and the second electrode of the first transistor and the second electrode of the second transistor are sources of the N-type transistors.

7. The wireless power receiving circuit according to any one of claims 1 to 6, wherein: The processing module includes: a control unit and a modulation unit; The output end of the control unit is connected to the input end of the modulation unit, and the output end of the modulation unit is connected to the control end of the impedance adjustment module; the control unit is used to: generate a control signal according to the communication information, and transmit the control signal to the modulation unit; the modulation unit is used to: modulate the control signal to generate a modulation signal, and the modulation signal is used to control the conduction and shutdown of the impedance adjustment module.

8. The wireless power receiving circuit according to any one of claims 1 to 7, wherein: The impedance compensation module includes: a third capacitor; The first plate of the third capacitor is connected to the first end of the receiving coil and the first end of the impedance adjustment module, and the second plate of the third capacitor is connected to the first input end of the rectifier module and the second end of the impedance adjustment module.

9. The wireless power receiving circuit according to claim 8, wherein: The impedance compensation module further includes: a fourth capacitor and an inductor; The second plate of the third capacitor is connected to the first plate of the fourth capacitor and the first end of the inductor, the second end of the inductor is connected to the first input end of the rectifier module and the second end of the impedance adjustment module; the second plate of the fourth capacitor is connected to the second end of the receiving coil.

10. The wireless power receiving circuit according to any one of claims 1 to 9, wherein: The rectifier module is a full-wave rectifier circuit or a half-wave rectifier circuit.

11. An electronic device, characterized in that: A wireless power receiving circuit comprising a load and the wireless power receiving circuit according to any one of claims 1 to 10; The output end of the wireless power receiving circuit is connected to the load, and is used to output an electrical signal to the load.

12. A wireless charging system, characterized in that: The invention comprises a wireless charging device and the electronic device as claimed in claim 11, wherein the wireless charging device is used to wirelessly charge the electronic device.

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