Wireless charging receiving end circuit, signal modulation method, system and chip

Abstract

The invention provides a wireless charging receiving end circuit, a signal modulation method and system and a chip, and relates to the technical field of wireless charging. The wireless charging receiving end circuit comprises a receiving coil, a receiving end compensation capacitor, a multiplexing compensation capacitor circuit, a synchronous rectification circuit, an output capacitor and a modulation and control circuit, the multiplexing compensation capacitor circuit is connected with the receiving end compensation capacitor in parallel, the controlled end of the multiplexing compensation capacitor circuit is connected with the first control end of the modulation and control circuit, and the second control end of the modulation and control circuit is connected with the controlled end of the synchronous rectification circuit; in the communication modulation stage, the modulation and control circuit determines a target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit according to a target modulation depth determined based on the load power of the output end of the synchronous rectification circuit; and the multiplexing compensation capacitor circuit is controlled to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor. According to the scheme, system energy consumption, heating, PCB occupied space and cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of wireless charging technology, and in particular to a wireless charging receiver circuit, signal modulation method, system and chip. Background Technology

[0002] Wireless charging is a power transmission method that uses spatial electromagnetic fields to transfer energy to a load, eliminating the need for power cables or other direct physical connections. Compared to traditional wired charging and electrode contact charging, wireless charging offers greater convenience, improves device waterproofing, and supports simultaneous charging of multiple devices. It has found widespread application in wireless charging fields ranging from low-power mobile devices to high-power electric vehicles.

[0003] Figure 1 A schematic diagram of the structure of a wireless charging system in the related art is shown, with reference to... Figure 1 As shown, the DC voltage provided by the DC power supply Vin is converted into AC power by the transmitter inverter, which drives the resonant circuit composed of the transmitter compensation capacitor C1 and the transmitter coil L1 to generate a high-frequency magnetic field. According to the law of electromagnetic induction, the receiver coil L2 can induce a high-frequency AC current. This high-frequency AC current passes through the receiver compensation capacitor C2 and enters the receiver rectifier for rectification before being output to the load RL. Here, k represents the coupling coefficient between the transmitter and receiver. In actual wireless charging systems, problems such as power outages, overvoltages, and overcurrents at the receiver due to input fluctuations, coupling changes, and sudden load changes exist. Therefore, the wireless charging system requires closed-loop control. According to the working principle of the wireless charging system, due to the air gap between the transmitter and receiver, the traditional closed-loop control method cannot be used for rapid control of the wireless charging system. Instead, information is loaded into the energy transmission channel, and electromagnetic field coupling is used to transmit information between the transmitter and receiver. When the receiver transmits a signal to the transmitter, the reverse transmission of the signal is usually achieved by adjusting the receiver impedance.

[0004] In related technologies, a modulation resistor can be connected to the output of the rectifier at the receiving end. By controlling the switching in and out of the modulation resistor, the impedance of the receiving end can be changed, thereby achieving signal modulation and transmission. However, the charging system needs to continuously communicate between the transmitter and receiver throughout the charging process. Due to the presence of the modulation resistor, this impedance adjustment method consumes energy for normal system transmission, which not only reduces system efficiency but also leads to heat generation problems. Summary of the Invention

[0005] This application provides a wireless charging receiver circuit, signal modulation method, system, and chip to solve the problem that the impedance adjustment method of the receiver in the prior art reduces the efficiency of the wireless charging system and causes heat generation. It realizes signal modulation at the receiver of the wireless charging system, thereby reducing the energy consumption and heat generation of the wireless charging system.

[0006] In a first aspect, this application provides a wireless charging receiver circuit, including a receiving coil, a receiver compensation capacitor, a multiplexed compensation capacitor circuit, a synchronous rectification circuit, an output capacitor, and a modulation and control circuit. One end of the receiving coil is connected to the first input terminal of the synchronous rectification circuit through the receiving end compensation capacitor, and the other end of the receiving coil is connected to the second input terminal of the synchronous rectification circuit. The output capacitor is connected between the positive output terminal and the negative output terminal of the synchronous rectification circuit. The multiplexing compensation capacitor circuit is connected in parallel across the two ends of the receiving end compensation capacitor, and the controlled end of the multiplexing compensation capacitor circuit is connected to the first control end of the modulation and control circuit, and the second control end of the modulation and control circuit is connected to the controlled end of the synchronous rectification circuit. The modulation and control circuit is used to determine the target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit according to the target modulation depth during the communication modulation stage, and to control the multiplexing compensation capacitor circuit to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor; wherein, the target modulation depth is determined based on the load power between the positive output terminal and the negative output terminal of the synchronous rectification circuit.

[0007] In one alternative design, the multiplexing compensation capacitor circuit includes at least one multiplexing compensation capacitor branch, each of the multiplexing compensation capacitor branches including a multiplexing compensation capacitor and a switching transistor; The first terminal of the multiplexing compensation capacitor is connected to the first terminal of the receiving compensation capacitor, and the second terminal of the multiplexing compensation capacitor is connected to the second terminal of the receiving compensation capacitor through the switching transistor. The controlled terminal of the switching transistor is connected to one of the controlled sub-terminals of the multiplexing controlled terminal of the multiplexing compensation capacitor circuit and one of the control sub-terminals of the first control terminal of the modulation and control circuit. The modulation and control circuit controls the switching transistors corresponding to each multiplexed compensation capacitor in the target multiplexed compensation capacitor to turn the target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor by controlling the switching transistors to turn on and off.

[0008] In one alternative design, the modulation and control circuit includes a modulation circuit and a receiver controller; The first output terminal of the receiver controller is connected to the input terminal of the modulation circuit. The second output terminal of the receiver controller is connected to the controlled terminal of the synchronous rectification circuit as the second control terminal of the modulation and control circuit. The first output terminal of the modulation circuit is connected to the controlled terminal of the multiplexed compensation capacitor circuit as the first control terminal of the modulation and control circuit. Furthermore, one output sub-terminal of the first output terminal of the modulation circuit is connected to the controlled terminal of one of the switching transistors in the multiplexed compensation capacitor circuit as a control sub-terminal of the first control terminal of the modulation and control circuit. The receiver controller is used to determine the target modulation depth of the signal to be transmitted based on the load power between the positive and negative output terminals of the synchronous rectifier circuit during the communication modulation stage, and generate a multiplexing capacitor control signal based on the target modulation depth and send it to the modulation circuit; the multiplexing capacitor control signal is used to indicate the target multiplexing compensation capacitor branch to be modulated in the multiplexing compensation capacitor circuit. The modulation circuit amplifies the power of the multiplexed capacitor control signal to obtain a switching transistor drive signal, and sends the switching transistor drive signal to the multiplexed compensation capacitor circuit to control the switching transistors of each multiplexed compensation capacitor branch in the target multiplexed compensation capacitor branch to continuously turn on and off.

[0009] In one alternative design, the greater the load power, the greater the capacitance value of the target multiplexed compensation capacitor cut off from both ends of the receiving end compensation capacitor by the multiplexing compensation capacitor circuit.

[0010] In an optional design, the modulation and control circuit is further configured to control all multiplexing compensation capacitors of the multiplexing compensation capacitor circuit to be connected in parallel across the two ends of the receiving compensation capacitor during the non-communication modulation phase after the wireless charging receiver circuit is powered on.

[0011] In an alternative design, when the wireless charging receiver circuit is not powered on, all the multiplexing compensation capacitors in the multiplexing compensation capacitor circuit are disconnected from the receiver compensation capacitor.

[0012] Secondly, this application provides a signal modulation method applied to the modulation and control circuit in the wireless charging receiver circuit as described in any of the first aspects above; the signal modulation method includes: During the communication modulation stage, the target modulation depth is determined based on the load power between the positive and negative output terminals of the synchronous rectifier circuit. The target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit is determined according to the target modulation depth, and the multiplexing compensation capacitor circuit is controlled to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor in order to modulate the signal to be transmitted in the wireless charging receiving end circuit.

[0013] Thirdly, this application provides a wireless charging system, including a wireless charging transmitter circuit and a wireless charging receiver circuit as described in any of the first aspects above; the wireless charging transmitter circuit and the wireless charging receiver circuit are coupled through the transmitting coil of the wireless charging transmitter circuit and the receiving coil of the wireless charging receiver circuit.

[0014] Fourthly, this application provides a chip including the wireless charging receiver circuit described in any of the first aspects above.

[0015] Fifthly, this application provides an electronic device including a wireless charging receiver circuit as described in any of the first aspects above, or including a chip as described in the fourth aspect above.

[0016] The wireless charging receiver circuit, signal modulation method, system, and chip provided in this application include a receiving coil, a receiving compensation capacitor, a multiplexing compensation capacitor circuit, a synchronous rectification circuit, an output capacitor, and a modulation and control circuit. One end of the receiving coil is connected to the first input terminal of the synchronous rectification circuit through the receiving compensation capacitor, and the other end of the receiving coil is connected to the second input terminal of the synchronous rectification circuit. The output capacitor is connected between the positive and negative output terminals of the synchronous rectification circuit. The multiplexing compensation capacitor circuit is connected in parallel across the receiving compensation capacitor, and the controlled terminal of the multiplexing compensation capacitor circuit is connected to the first control terminal of the modulation and control circuit, while the second control terminal of the modulation and control circuit is connected to the controlled terminal of the synchronous rectification circuit. During the communication modulation stage, the modulation and control circuit determines the target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit based on the target modulation depth determined by the load power between the positive and negative output terminals of the synchronous rectification circuit, and controls the multiplexing compensation capacitor circuit to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving compensation capacitor. In this way, different target multiplexing compensation capacitors can be switched in and out during the communication modulation stage according to the actual required target modulation depth. By switching in and out of the target multiplexing compensation capacitors, the impedance of the receiving end can be adjusted, thus completing the modulation of the receiving signal. It can reuse the resonant compensation capacitor at the receiving end as a modulation capacitor, and use the change of capacitance value to change the impedance characteristics of the receiving end. Compared with the impedance modulation scheme using the modulation resistor at the output end in related technologies, it consumes less energy, which can effectively reduce the energy consumption of the wireless charging system, improve the system efficiency, and reduce the system heat generation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a wireless charging system in related technologies; Figure 2 This is a schematic diagram illustrating the principle of receiver impedance adjustment methods in related technologies; Figure 3 This is one of the structural schematic diagrams of the wireless charging receiver circuit provided in the embodiments of this application; Figure 4 A second schematic diagram of the wireless charging receiver circuit provided in the embodiments of this application; Figure 5 A schematic flowchart illustrating the signal modulation method provided in an embodiment of this application; Figure 6 This is one of the structural schematic diagrams of the wireless charging system provided in the embodiments of this application; Figure 7 This is a second schematic diagram of the structure of the wireless charging system provided in the embodiments of this application. Detailed Implementation

[0018] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c. a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] The terms "connected" and "connected" should be interpreted broadly. For example, in circuit structures, "connected" or "connected" can refer not only to physical connections but also to electrical or signal connections. This could be a direct connection (physical connection) or an indirect connection via at least one intermediate component, as long as the circuit is connected. It could also refer to the internal connection between two components. Similarly, a signal connection can refer to a connection via a circuit or a medium, such as radio waves. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0021] Wireless charging is a power transmission method that uses spatial electromagnetic fields to transfer power to a load without the need for power transmission lines or other direct physical connections.

[0022] Reference Figure 1 As shown, the wireless charging system can include an energy transmission section and a signal transmission section, both controlled by a transmitter controller and a receiver controller. The energy transmission section can include a DC power supply Vin, a transmitter inverter, a transmitter compensation capacitor C1, a transmitter coil L1, a receiver coil L2, a receiver compensation capacitor C2, a receiver rectifier, an output capacitor C0, and a load RL. The signal transmission section can include a transmitter sampling circuit, a demodulation circuit, a transmitter controller, a modulation circuit, a receiver sampling circuit, and a receiver controller. The basic working principle of the wireless charging system is as follows: the transmitter inverter converts the DC power output from the DC power supply Vin into high-frequency AC power. This high-frequency AC power drives a resonant circuit composed of the transmitter compensation capacitor C1 and the transmitter coil L1 to generate a high-frequency magnetic field. The receiver coil L2 is placed in this high-frequency magnetic field. According to Faraday's law of electromagnetic induction, a high-frequency AC power will be induced in the receiver coil L2. This high-frequency AC power passes through the receiver compensation capacitor C2 and enters the receiver rectifier. After rectification, the receiver rectifier outputs the rectified power to the load RL. This allows energy to be transferred from the transmitter to the receiver using electromagnetic fields, thus enabling wireless charging.

[0023] The transmitter and receiver can communicate through the signal transmission section, combined with Figure 1 According to the working principle of wireless charging system, due to the existence of air gap between the transmitter and receiver, the traditional closed-loop control method cannot be used to quickly control the wireless charging system. Instead, the information is loaded into the energy transmission channel and the information is transmitted between the transmitter and receiver by electromagnetic field coupling.

[0024] Specifically, the receiver controller loads the electrical signal sampled by the receiver and other signal packets into the energy transmission channel through a modulation circuit, and uses electromagnetic field coupling to transmit the receiver signal from the receiver to the transmitter.

[0025] In practical wireless charging systems, issues such as power outages, overvoltages, and overcurrents at the receiver can arise due to input fluctuations, coupling changes, and sudden load changes. Therefore, wireless charging systems require closed-loop control. The receiver feeds back charging-related information and protocol-related information to the transmitter, enabling the transmitter to adjust its operating state in real time and ensure the system operates at its optimal condition. For the receiver, when transmitting signals to the transmitter, impedance adjustment is typically used to achieve reverse signal transmission.

[0026] Figure 2 A schematic diagram illustrating the principle of receiver impedance adjustment methods in related technologies is shown below. Figure 2 As shown, impedance adjustment at the receiving end can be achieved using resistor modulation. A modulation resistor RM is connected to the output of the rectifier at the receiving end. By controlling the on / off state of the load resistor modulation switch S3 to switch the modulation resistor RM in or out of the circuit, impedance adjustment is achieved. Specifically, the receiving end sampling circuit collects the electrical signal at the receiving end and transmits it to the receiving end controller. The receiving end controller encodes the electrical signal and converts the encoded signal into a first switch drive signal in the modulation circuit. This first switch drive signal controls the load resistor modulation switch S3 to switch the modulation resistor RM in or out of the circuit, thereby changing the impedance characteristics of the receiving end and completing the modulation of the receiving end signal. The transmitting end can collect the voltage or current signal of the transmitting end resonant cavity. The sampled electrical signal is passed through the demodulation circuit for envelope detection and signal conditioning. Finally, the obtained signal is transmitted to the transmitting end controller for decoding, thereby obtaining the information transmitted by the receiving end. Then, based on the decoded information, the transmitting end inverter is adjusted to control the energy transmitted to the receiving end, completing the closed-loop control of the wireless system.

[0027] However, in this resistor modulation scheme, since the transmitter and receiver need to communicate at all times during the entire charging process, the modulation resistor RM will consume the energy normally transmitted by the system during modulation, thereby reducing the efficiency of the system. Moreover, the modulation resistor RM will also cause the receiver to overheat.

[0028] Therefore, in one embodiment, reference is made to Figure 2As shown, impedance adjustment at the receiving end can also be achieved using capacitor modulation. Modulation capacitors C01 and C02 are connected at the midpoint of the receiving end rectifier. Switches S1 and S2 control the switching on and off of modulation capacitors C01 and C02, thus changing the impedance at the receiving end. Specifically, the receiving end sampling circuit collects the electrical signal and transmits it to the receiving end controller. The receiving end controller encodes the electrical signal and converts it into a second switch drive signal in the modulation circuit. This second switch drive signal controls switches S1 and S2 to switch modulation capacitors C01 and C02 on or off, thereby changing the impedance characteristics of the receiving end and completing the modulation of the receiving signal. The transmitting end can collect the voltage or current signal from the transmitting end resonant cavity. The sampled electrical signal is then subjected to envelope detection and signal conditioning by a demodulation circuit. Finally, the obtained signal is transmitted to the transmitting end controller for decoding, thus obtaining the information sent by the receiving end. Based on the decoded information, the transmitting end inverter is adjusted to control the energy transmitted to the receiving end, completing the closed-loop control of the wireless system.

[0029] While this capacitor modulation scheme avoids the heat generation problem of the resistor modulation scheme, the difficulty in integrating the modulation capacitor into the chip and the placement of multiple modulation capacitors will occupy additional space, resulting in a larger printed circuit board (PCB) area for this scheme. To a certain extent, this places higher demands on high-density design, and the presence of additional modulation capacitors also increases the cost of the system.

[0030] Both the resistor modulation and capacitor modulation schemes mentioned above require multiple independent and controllable modulation branches to meet the modulation requirements of a full range of loads. This places higher demands on high-density designs (such as wireless charging systems for watches and mobile phones). Capacitor modulation requires additional space, while resistor modulation, although it can integrate the modulation resistor inside the chip, consumes some of the energy normally transmitted by the system, reducing system efficiency and causing the chip to overheat.

[0031] Based on this, this application provides a wireless charging system receiver signal modulation scheme that can reduce additional PCB space occupation, lower costs, and reduce energy consumption. The resonant compensation capacitor at the receiver is reused as a modulation capacitor capable of impedance modulation at the receiver. A reused compensation capacitor circuit is connected in parallel across the receiver compensation capacitor in the wireless charging receiver circuit. The controlled terminal of the reused compensation capacitor circuit is connected to the first control terminal of the modulation and control circuit of the wireless charging receiver circuit. During the communication modulation stage, the modulation and control circuit can determine the target reused compensation capacitor to be modulated in the reused compensation capacitor circuit based on the target modulation depth determined by the load power between the positive and negative output terminals of the synchronous rectifier circuit. The circuit then controls the reused compensation capacitor circuit to continuously switch the target reused compensation capacitor into and out of the receiver compensation capacitor, thereby adjusting the receiver impedance and completing the modulation of the receiver signal. It can reuse the resonant compensation capacitor at the receiving end as a modulation capacitor, and use the change of capacitance value to change the impedance characteristics of the receiving end. Compared with the impedance modulation scheme using the modulation resistor at the output end in related technologies, it consumes less energy, which can effectively reduce the energy consumption of the wireless charging system, improve the system efficiency, and reduce the system heat generation.

[0032] Furthermore, once the operating frequency and coupling parameters of a wireless charging system are determined, the parameters of its receiver's resonant compensation capacitor (i.e., the value of the compensation capacitor at the receiver) are also determined. It is often difficult to find an existing capacitor that corresponds to this value, thus requiring a combination of multiple different capacitors. In practical applications, regardless of the specific design, sufficient space must be reserved for the compensation capacitor. Therefore, using a multiplexed compensation capacitor scheme to achieve impedance adjustment at the receiver does not occupy additional PCB space. Simultaneously, it effectively reduces system cost.

[0033] The following is combined with Figures 3-4 The wireless charging receiver circuit provided in the embodiments of this application will be described in detail. The wireless charging receiver circuit is the circuit on the receiving side of the wireless charging system, that is, the circuit on the side of the device being charged.

[0034] Figure 3 This paper shows one of the structural schematic diagrams of the wireless charging receiver circuit provided in an embodiment of this application. (Refer to...) Figure 3 As shown, the wireless charging receiver circuit includes a receiving coil L2, a receiving compensation capacitor C2, a multiplexing compensation capacitor circuit 31, a synchronous rectification circuit 32, an output capacitor C0, and a modulation and control circuit 33.

[0035] One end of the receiving coil L2 is connected to the first input terminal H1 of the synchronous rectification circuit 32 through the receiving end compensation capacitor C2, and the other end of the receiving coil L2 is connected to the second input terminal H2 of the synchronous rectification circuit 32. The output capacitor C0 is connected between the positive output terminal and the negative output terminal of the synchronous rectification circuit 32. The multiplexed compensation capacitor circuit 31 is connected in parallel across the two ends of the receiving end compensation capacitor C2, and the controlled terminal of the multiplexed compensation capacitor circuit 31 is connected to the first control terminal P1 of the modulation and control circuit 33. The second control terminal P2 of the modulation and control circuit 33 is connected to the controlled terminal of the synchronous rectification circuit 32. The output terminal of the modulation and control circuit 33 is used to connect to the load RL, which is, for example, a voltage regulation circuit such as a low-dropout regulator (LDO) circuit.

[0036] The receiving coil L2 is located in the high-frequency magnetic field generated by the transmitter of the wireless charging system. According to Faraday's law of electromagnetic induction, a high-frequency alternating current will be induced in the receiving coil L2. This high-frequency alternating current enters the synchronous rectification circuit 32 after passing through the compensation capacitor C2 at the receiving end. Under the control of the modulation and control circuit 33, the synchronous rectification circuit 32 can rectify the high-frequency alternating current and output it to the load RL.

[0037] In this embodiment, the modulation and control circuit 33 can also be used during the communication modulation stage to determine the target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit 31 according to the target modulation depth, and control the multiplexing compensation capacitor circuit 31 to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2; wherein, the target modulation depth is determined based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32. In this way, the compensation capacitor value of the receiving end can be changed by switching the target multiplexing compensation capacitor into and out, thereby adjusting the impedance of the receiving end and completing the modulation of the receiving end signal.

[0038] Specifically, the greater the load power between the positive and negative output terminals of the synchronous rectifier circuit 32, the greater the modulation depth required by the wireless charging receiver circuit during the communication modulation stage, i.e., the greater the target modulation depth, and correspondingly, the larger the capacitance value of the target multiplexed compensation capacitor across the receiver compensation capacitor C2 cut out by the multiplexed compensation capacitor circuit 31.

[0039] For example, a first correspondence between load power and modulation depth and a second correspondence between modulation depth and capacitance value of multiplexing compensation capacitor can be established in advance. Modulation and control circuit 33 can determine the target modulation depth based on the first correspondence according to the load power between the positive and negative output terminals of synchronous rectifier circuit 32. Then, based on the target modulation depth, it can determine the capacitance value of target multiplexing compensation capacitor using the second correspondence. Based on the capacitance value of target multiplexing compensation capacitor, it can determine the target multiplexing compensation capacitor to be modulated and the corresponding control signal in multiplexing compensation capacitor circuit 31. Using the control signal, multiplexing compensation capacitor circuit 31 can control the target multiplexing compensation capacitor to continuously switch in and out of the two ends of receiving end compensation capacitor C2. By changing the compensation capacitor value of receiving end, the impedance of receiving end can be adjusted, and the modulation of receiving end signal can be completed.

[0040] For example, the first correspondence can also be the correspondence between load power, coupling coefficient and modulation depth.

[0041] For example, the first correspondence can be a one-to-one correspondence between different load power ranges and different modulation depths, or a one-to-one correspondence between different load power ranges, different coupling coefficient ranges and different modulation depths.

[0042] For example, a third correspondence between the load power and the capacitance value of the multiplexing compensation capacitor can be established in advance, or a third correspondence between the load power, the coupling system, and the capacitance value of the multiplexing compensation capacitor can be established in advance. The modulation and control circuit 33 can determine the capacitance value of the target multiplexing compensation capacitor directly using the third correspondence based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32, or based on the coupling coefficient of the load power and the system. Then, based on the capacitance value of the target multiplexing compensation capacitor, the target multiplexing compensation capacitor to be modulated and the corresponding control signal in the multiplexing compensation capacitor circuit 31 are determined. The control signal is used to control the multiplexing compensation capacitor circuit 31 to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2.

[0043] For example, the third correspondence can be a one-to-one correspondence between different load power ranges and different capacitance values ​​of multiplexed compensation capacitors, or a one-to-one correspondence between different load power ranges, different coupling coefficient ranges and different capacitance values ​​of multiplexed compensation capacitors.

[0044] Alternatively, a fourth correspondence can be pre-established between the load power and the multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit 31. The modulation and control circuit 33 can directly determine the target multiplexed compensation capacitor to be modulated from this fourth correspondence based on the load power. Optionally, the fourth correspondence can also be a correspondence between the load power, the coupling coefficient, and the multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit 31. The modulation and control circuit 33 can directly determine the target multiplexed compensation capacitor to be modulated from this fourth correspondence based on the load power and the system coupling coefficient.

[0045] For example, the multiplexed compensation capacitor circuit 31 may include at least one multiplexed compensation capacitor branch, such as... Figure 3 As shown, there may be n multiplexed compensation capacitor branches, including a first multiplexed compensation capacitor branch, a second multiplexed compensation capacitor branch, ... and an nth multiplexed compensation capacitor branch. Each multiplexed compensation capacitor branch can provide a capacitance value, where n is a positive integer.

[0046] Correspondingly, during the communication modulation stage, the modulation and control circuit 33 can determine the target multiplexed compensation capacitor branch corresponding to the target modulation depth from the n multiplexed compensation capacitor branches, and then control the multiplexed compensation capacitor circuit 31 to continuously turn these target multiplexed compensation capacitor branches on and off, so as to continuously switch the corresponding target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2, adjust the compensation capacitor value of the receiving end, thereby changing the impedance characteristics of the receiving end, realizing the adjustment of the receiving end impedance, and completing the modulation of the receiving end signal.

[0047] The wireless charging receiver circuit provided in this application can determine the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit according to the actual required target modulation depth during the communication modulation stage, and control these target multiplexed compensation capacitors to continuously switch in and out to adjust the impedance of the receiver and complete the modulation of the receiver signal. It can reuse the resonant compensation capacitor of the receiver as a modulation capacitor, using changes in capacitance value to change the impedance characteristics of the receiver. Compared with the related technology that uses the modulation resistor at the output end for impedance modulation, it consumes less energy, effectively reducing the energy consumption of the wireless charging system, improving system efficiency, and reducing system heat generation. Moreover, since the parameters of the resonant compensation capacitor at the receiver end (i.e., the compensation capacitor value of the receiver end) are also determined after the operating frequency and coupling parameters of the wireless charging system are determined, and it is usually difficult to find an existing capacitor with a corresponding compensation capacitor value, it is necessary to combine multiple different capacitors. In practical applications, regardless of the application design, sufficient space must be reserved for the compensation capacitor. Therefore, using the compensation capacitor multiplexing scheme to achieve impedance adjustment at the receiver end will not occupy additional PCB space, and effectively reduce the system cost.

[0048] based on Figure 3 The wireless charging receiver circuit corresponding to the embodiment, Figure 4 This is a second schematic diagram of the wireless charging receiver circuit provided in an embodiment of this application. (Refer to...) Figure 4 As shown, the wireless charging receiver circuit includes a receiving coil L2, a receiving compensation capacitor C2, a multiplexing compensation capacitor circuit 31, a synchronous rectification circuit 32, an output capacitor C0, and a modulation and control circuit 33. The multiplexing compensation capacitor circuit 31 includes at least one multiplexing compensation capacitor branch, each branch including a multiplexing compensation capacitor and a switching transistor. For each multiplexing compensation capacitor branch, the first terminal of its multiplexing compensation capacitor is connected to the first terminal of the receiving compensation capacitor C2, and the second terminal of the multiplexing compensation capacitor is connected to the second terminal of the receiving compensation capacitor C2 through the switching transistor. The controlled terminal of the switching transistor, as one of the controlled terminals of the multiplexing compensation capacitor circuit 31, is connected to one of the control terminals P1 of the modulation and control circuit 33.

[0049] The modulation and control circuit 33 controls the switching transistors corresponding to each multiplexed compensation capacitor in the target multiplexed compensation capacitor to turn the target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2 by controlling the switching transistors of each multiplexed compensation capacitor in the target multiplexed compensation capacitor. Meanwhile, the other multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 remain in the in state. In this way, by changing the compensation capacitor value of the receiving end, the impedance of the receiving end is adjusted, and the modulation of the receiving end signal is completed.

[0050] For example, the switching transistors in each multiplexed compensation capacitor branch can be metal-oxide-semiconductor field-effect transistors (MOS transistors).

[0051] For example, in Figure 4 In the circuit, the multiplexed compensation capacitor circuit 31 may include a first multiplexed compensation capacitor branch 311, a second multiplexed compensation capacitor branch 312, ... and an nth multiplexed compensation capacitor branch 31n, for a total of n multiplexed compensation capacitor branches. The first multiplexed compensation capacitor branch 311 includes a first multiplexed compensation capacitor CM1 and a first switch SM1, the second multiplexed compensation capacitor branch 312 includes a second multiplexed compensation capacitor CM2 and a second switch SM2, ..., and the nth multiplexed compensation capacitor branch 31n includes an nth multiplexed compensation capacitor CMn and an nth switch SMn.

[0052] Taking a MOSFET as an example, the first terminal of the first multiplexing compensation capacitor CM1 is connected to the first terminal of the receiving compensation capacitor C2. The second terminal of the first multiplexing compensation capacitor CM1 is connected to the drain of the first switching transistor SM1. The source of the first switching transistor SM1 is connected to the second terminal of the receiving compensation capacitor C2. The gate (i.e., the controlled terminal) of the first switching transistor SM1 is connected to the first control terminal P11 of the first control terminal P1 of the modulation and control circuit 33, as one of the controlled terminals of the multiplexing compensation capacitor circuit 31. The first terminal of the second multiplexing compensation capacitor CM2 is connected to the first terminal of the receiving compensation capacitor C2. The second terminal of the second multiplexing compensation capacitor CM2 is connected to the drain of the second switching transistor SM2. The source of the second switching transistor SM2 is connected to the receiving terminal. The second terminal of the compensation capacitor C2 is connected to the second control sub-terminal P12 in the first control terminal P1 of the modulation and control circuit 33, and the gate (i.e., the controlled terminal) of the second switch SM2 is connected as a controlled sub-terminal in the multiplexed controlled terminal of the multiplexed compensation capacitor circuit 31; ... The first terminal of the nth multiplexed compensation capacitor CMn is connected to the first terminal of the receiving compensation capacitor C2, the second terminal of the nth multiplexed compensation capacitor CMn is connected to the drain of the nth switch SMn, the source of the nth switch SMn is connected to the second terminal of the receiving compensation capacitor C2, and the gate (i.e., the controlled terminal) of the nth switch SMn is connected as a controlled sub-terminal in the multiplexed controlled terminal of the multiplexed compensation capacitor circuit 31 to the nth control sub-terminal P1n in the first control terminal P1 of the modulation and control circuit 33.

[0053] according to Figure 4In the wireless charging receiver circuit shown, during the communication modulation stage, the modulation and control circuit 33 can determine the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit 31 based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32. For example, if it is determined that the first multiplexed compensation capacitor CM1 and the second multiplexed compensation capacitor CM2 need to be switched out to meet the target modulation depth requirement corresponding to the load power, the modulation and control circuit 33 can send switching drive signals to the first switch transistor SM1 and the second switch transistor SM2 through the first control sub-terminal P11 and the second control sub-terminal P12 respectively. Through the switching drive signal, the first switch transistor SM1 and the second switch transistor SM2 are controlled to continuously turn on and off, so that the first multiplexed compensation capacitor CM1 and the second multiplexed compensation capacitor CM2 continuously switch in and out of the two ends of the receiver compensation capacitor C2. Meanwhile, the switches corresponding to other multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 remain in the previous on state so that other multiplexed compensation capacitors remain in the switched-in state. In this way, by changing the compensation capacitor value of the receiver, the impedance of the receiver can be adjusted, and the modulation of the receiver signal can be completed.

[0054] It is understandable that each multiplexed compensation capacitor in the multiplexed compensation capacitor circuit 31 can form different capacitance gradients according to the control combination of their respective corresponding switching transistors, thereby meeting the modulation depth requirements under full-range load conditions.

[0055] Reference Figure 4 In one embodiment of the wireless charging receiver circuit shown in this application, the modulation and control circuit 33 includes a modulation circuit 331 and a receiver controller 332.

[0056] In this circuit, the first output terminal P3 of the receiver controller 332 is connected to the input terminal of the modulation circuit 331, the second output terminal of the receiver controller 332 is connected to the controlled terminal of the synchronous rectification circuit 32 as the second control terminal P2 of the modulation and control circuit 33, and the first output terminal of the modulation circuit 331 is connected to the controlled terminal of the multiplexed compensation capacitor circuit 31 as the first control terminal P1 of the modulation and control circuit 33; and one of the output sub-terminals of the first output terminal of the modulation circuit 331 is connected to the controlled terminal of one of the switching transistors in the multiplexed compensation capacitor circuit 31 as a control sub-terminal of the first control terminal P1 of the modulation and control circuit 33.

[0057] For example in Figure 4In the modulation circuit 331, the first output sub-terminal of the first output terminal is connected to the gate (i.e., the controlled terminal) of the first switching transistor SM1 as the first control sub-terminal P11 of the modulation and control circuit 33. The second output sub-terminal of the first output terminal of the modulation circuit 331 is connected to the gate (i.e., the controlled terminal) of the second switching transistor SM2 as the second control sub-terminal P12 of the modulation and control circuit 33. ... The nth output sub-terminal of the first output terminal of the modulation circuit 331 is connected to the gate (i.e., the controlled terminal) of the nth switching transistor SMn as the nth control sub-terminal P1n of the modulation and control circuit 33.

[0058] The receiver controller 332 is used to determine the target modulation depth of the signal to be transmitted based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32 during the communication modulation stage, and generate a multiplexing capacitor control signal based on the target modulation depth and send it to the modulation circuit 331; the multiplexing capacitor control signal is used to indicate the target multiplexing compensation capacitor branch to be modulated in the multiplexing compensation capacitor circuit 31. The modulation circuit 331 is used to amplify the power of the multiplexed capacitor control signal to obtain the switching transistor drive signal, and send the switching transistor drive signal to the multiplexed compensation capacitor circuit 31 to control the switching transistors of each multiplexed compensation capacitor branch in the target multiplexed compensation capacitor branch to continuously turn on and off.

[0059] Specifically, for example, if the receiver controller 332 determines that the first multiplexing compensation capacitor CM1 and the second multiplexing compensation capacitor CM2 need to be switched off to meet the target modulation depth requirements corresponding to the load power and system coupling coefficient, it sends a multiplexing capacitor control signal to the modulation circuit 331, indicating that the target multiplexing compensation capacitor branch to be modulated is the first multiplexing compensation capacitor branch 311 and the second multiplexing compensation capacitor branch 312, that is, indicating that the first switch SM1 and the second switch SM2 are controlled to turn on and off. The modulation circuit 331 amplifies the multiplexing capacitor control signal to obtain the switch drive signal, and sends the switch drive signal to the multiplexing compensation capacitor circuit 31 to control the first switch SM1 and the second switch SM2 to continuously turn on and off, and controls the other switches in the multiplexing compensation capacitor circuit 31 to remain on. In this way, the first multiplexed compensation capacitor CM1 and the second multiplexed compensation capacitor CM2 in the multiplexed compensation capacitor circuit 31 can be continuously switched in and out of the two ends of the receiving end compensation capacitor C2. By changing the compensation capacitor value at the receiving end, the impedance of the receiving end can be adjusted, and the modulation of the receiving end signal can be completed.

[0060] It is understandable that the multiplexing capacitor control signal sent by the receiver controller 332 to the modulation circuit 331 can be a control indication signal for controlling the turn-on or turn-off of each switch in the multiplexing compensation capacitor circuit 31. For a switch that needs to be turned on, its corresponding control indication signal can be a high-level signal "1", and for a switch that needs to be turned off, its corresponding control indication signal can be a low-level signal "0". The modulation circuit 331 amplifies these control indication signals and converts them into switch drive signals that can drive the switch. That is, the high-level signal "1" is converted into a high-level drive signal that can drive the switch to turn on after power amplification, while the low-level signal "0" remains in a low-level state.

[0061] Based on the wireless charging receiver circuits of the above embodiments, in one embodiment of this application, the modulation and control circuit 33 is further configured to control all multiplexing compensation capacitors of the multiplexing compensation capacitor circuit 31 to be connected in parallel across the two ends of the receiver compensation capacitor C2 during the non-communication modulation phase after the wireless charging receiver circuit is powered on.

[0062] For example, with Figure 4 For example, in the non-communication modulation stage after the wireless charging receiver circuit is powered on, such as the energy transmission stage after the communication modulation stage is completed, the modulation and control circuit 33 can control all the switching transistors in the multiplexing compensation capacitor circuit 31 to be turned on. At this time, all the multiplexing compensation capacitors in the multiplexing compensation capacitor circuit 31 are connected to the circuit and are connected in parallel with the receiver compensation capacitor C2.

[0063] Since the parameters of the receiving end's resonant compensation capacitor (i.e., the compensation capacitor value) are determined after the operating frequency and coupling parameters of the wireless charging system are set, this value is often difficult to find in existing capacitors. Therefore, multiple different capacitors need to be combined. Based on this, the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are determined according to the receiving end's resonant compensation capacitor parameters. The sum of the capacitance values ​​of all multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 and the receiving end compensation capacitor C2 is the capacitance value in the system's optimal resonant state. When all the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are connected to the circuit, the wireless charging system can enter the optimal resonant state, achieving the highest energy transfer efficiency.

[0064] Based on the wireless charging receiver circuits of the above embodiments, in one embodiment of this application, when the wireless charging receiver circuit is not powered on, all the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are disconnected from the receiver compensation capacitor C2.

[0065] For example, with Figure 4For example, when the wireless charging receiver circuit is not powered on, such as in the initial stage when the device to be charged at the receiver is close to or in contact with the charger or charging platform at the transmitter, the receiver is not powered. At this time, all the switching transistors in the multiplexed compensation capacitor circuit 31 are in the off state, and each multiplexed compensation capacitor is disconnected from the receiver compensation capacitor C2.

[0066] At this time, the compensation capacitor value of the receiving end is only the capacitance value of the receiving end compensation capacitor C2, which is less than the design value determined according to the resonant compensation capacitor parameters of the receiving end. At this time, the gain of the wireless charging system is greater than the gain when all the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are fully connected, which is beneficial to the rapid power-on of the receiving end.

[0067] Based on the wireless charging receiver circuits of the above embodiments, this application also provides a signal modulation method, which can be applied to the modulation and control circuits in the wireless charging receiver circuits provided in any of the above embodiments.

[0068] Figure 5 A schematic flowchart of the signal modulation method provided in an embodiment of this application is shown below. Figure 5 As shown, the signal modulation method may include the following steps 510 to 520.

[0069] Step 510: In the communication modulation stage, the target modulation depth is determined based on the load power between the positive and negative output terminals of the synchronous rectifier circuit.

[0070] For example, a first correspondence between load power and modulation depth can be established in advance, and the modulation and control circuit 33 can determine the target modulation depth based on the first correspondence according to the load power between the positive and negative output terminals of the synchronous rectifier circuit 32. Alternatively, a first correspondence between load power, coupling coefficient, and modulation depth can be established in advance, and the modulation and control circuit 33 can determine the target modulation depth based on the first correspondence according to the load power of the synchronous rectifier circuit 32 and the coupling coefficient of the system.

[0071] For example, the first correspondence between load power and modulation depth can be a one-to-one correspondence between different load power ranges and different modulation depths.

[0072] Step 520: Determine the target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit according to the target modulation depth, and control the multiplexing compensation capacitor circuit to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor in order to modulate the signal to be transmitted in the wireless charging receiving end circuit.

[0073] For example, a second correspondence between the modulation depth and the capacitance value of the multiplexing compensation capacitor can be established in advance. After obtaining the target modulation depth, the modulation and control circuit 33 can determine the capacitance value of the target multiplexing compensation capacitor based on the target modulation depth and the second correspondence. Then, based on the capacitance value of the target multiplexing compensation capacitor, the target multiplexing compensation capacitor to be modulated and the corresponding control signal in the multiplexing compensation capacitor circuit 31 are determined. The control signal is used to control the multiplexing compensation capacitor circuit 31 to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2. By changing the compensation capacitor value of the receiving end, the impedance of the receiving end is adjusted, and the modulation of the receiving end signal is completed.

[0074] For example, the second correspondence between modulation depth and the capacitance value of the multiplexing compensation capacitor can be a one-to-one correspondence between modulation depth and the capacitance value of the multiplexing compensation capacitor, or it can be a one-to-one correspondence between different modulation depth ranges and the capacitance value of the multiplexing compensation capacitor. The capacitance value of the multiplexing compensation capacitor is related to the multiplexing compensation capacitors used in the design of the multiplexing compensation capacitor circuit 31; different combinations of these multiplexing compensation capacitors can yield different capacitance values.

[0075] For example, a fifth correspondence between modulation depth and multiplexing compensation capacitor to be modulated in multiplexing compensation capacitor circuit 31 can be established in advance. Modulation and control circuit 33 can directly determine the target multiplexing compensation capacitor to be modulated from the fifth correspondence based on the target modulation depth, and then control multiplexing compensation capacitor circuit 31 to continuously switch the target multiplexing compensation capacitor into and out of the two ends of receiving end compensation capacitor C2. By changing the compensation capacitor value of receiving end, the impedance of receiving end can be adjusted, and the modulation of receiving end signal can be completed.

[0076] The signal modulation method provided in this application embodiment can be applied to the wireless charging receiver circuit provided in this application embodiment. During the communication modulation stage, the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit is determined according to the actual required target modulation depth. The switching in and out of these target multiplexed compensation capacitors is controlled to adjust the impedance of the receiver, thus achieving signal modulation at the receiver. This wireless charging receiver circuit can reuse the resonant compensation capacitor at the receiver as a modulation capacitor. By controlling the change in capacitance value, the impedance characteristics of the receiver can be changed. Compared with the impedance modulation scheme using the modulation resistor at the output end in related technologies, it consumes less energy, effectively reducing the energy consumption of the wireless charging system, improving system efficiency, and reducing system heat generation.

[0077] based on Figure 5In one embodiment of this application, the signal modulation method corresponding to the embodiment may further include: during the non-communication modulation phase after the wireless charging receiver circuit is powered on, controlling all multiplexing compensation capacitors of the multiplexing compensation capacitor circuit 31 to be connected in parallel across the two ends of the receiver compensation capacitor C2.

[0078] This allows the wireless charging system to enter its optimal resonant state, enabling the system to achieve its highest energy transfer efficiency.

[0079] This application also provides a wireless charging system, which includes a wireless charging transmitter circuit and a wireless charging receiver circuit as described in any of the above embodiments. The wireless charging transmitter circuit is located on the charger or charging platform side, and the wireless charging receiver circuit is located on the device being charged side. The wireless charging transmitter circuit and the wireless charging receiver circuit are coupled through the transmitting coil of the wireless charging transmitter circuit and the receiving coil of the wireless charging receiver circuit. Energy transfer and communication signal transmission between the transmitter and receiver can be achieved through coil coupling. This energy transfer can be unidirectional or bidirectional.

[0080] For example, Figure 6 This paper shows one of the structural schematic diagrams of a wireless charging system provided in an embodiment of this application. (Refer to...) Figure 6 As shown, the wireless charging system includes a wireless charging transmitter circuit 61 and a wireless charging receiver circuit 62. The wireless charging transmitter circuit 61 may include a DC power supply Vin, an inverter bridge circuit 611, a transmitter compensation capacitor C1, and a transmitter coil L1. The DC power supply Vin is connected between the two input terminals of the inverter bridge circuit 611, and the transmitter compensation capacitor C1 and the transmitter coil L1 are connected in series between the midpoints of the two bridge arms of the inverter bridge circuit 611.

[0081] The wireless charging receiver circuit 62 may include a receiving coil L2, a receiving compensation capacitor C2, a multiplexed compensation capacitor circuit 31, a synchronous rectification circuit 32, an output capacitor C0, and a modulation and control circuit 33. One end of the receiving coil L2 is connected to the first input terminal H1 of the synchronous rectification circuit 32 through the receiving compensation capacitor C2, and the other end of the receiving coil L2 is connected to the second input terminal H2 of the synchronous rectification circuit 32. The output capacitor C0 is connected between the positive and negative output terminals of the synchronous rectification circuit 32. The multiplexed compensation capacitor circuit 31 is connected in parallel across the receiving compensation capacitor C2, and the controlled terminal of the multiplexed compensation capacitor circuit 31 is connected to the first control terminal P1 of the modulation and control circuit 33. The second control terminal P2 of the modulation and control circuit 33 is connected to the controlled terminal of the synchronous rectification circuit 32. The output terminal of the modulation and control circuit 33 is used to connect to the load RL.

[0082] The wireless charging transmitter circuit 61 and the wireless charging receiver circuit 62 are coupled through the transmitting coil L1 and the receiving coil L2. Here, k represents the coupling coefficient.

[0083] according to Figure 6 In the wireless charging system shown, the DC power supply Vin of the wireless charging transmitter circuit 61 can provide energy. The DC voltage provided by Vin is converted into AC power by the inverter bridge circuit 611, which drives the resonant circuit composed of the transmitter compensation capacitor C1 and the transmitter coil L1 to generate a high-frequency magnetic field. According to the law of electromagnetic induction, the receiving coil L2 of the wireless charging receiver circuit 62 can induce a high-frequency AC power. This high-frequency AC power enters the synchronous rectification circuit 32 after passing through the receiver compensation capacitor C2. Under the control of the modulation and control circuit 33, the synchronous rectification circuit 32 can rectify the high-frequency AC power and output it to the load RL.

[0084] During the communication modulation stage, the modulation and control circuit 33 can be used to determine the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit 31 according to the target modulation depth, and control the multiplexed compensation capacitor circuit 31 to continuously switch the target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2; wherein, the target modulation depth is determined based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32. In this way, by switching the target multiplexed compensation capacitor into and out, the compensation capacitor value of the receiving end can be changed, thereby adjusting the impedance of the receiving end and completing the modulation of the receiving end signal.

[0085] For example, the multiplexed compensation capacitor circuit 31 may include at least one multiplexed compensation capacitor branch, such as... Figure 6 As shown, there may be n multiplexed compensation capacitor branches, including a first multiplexed compensation capacitor branch, a second multiplexed compensation capacitor branch, ... and an nth multiplexed compensation capacitor branch. Each multiplexed compensation capacitor branch can provide a capacitance value, where n is a positive integer.

[0086] Correspondingly, during the communication modulation stage, the modulation and control circuit 33 can determine the target multiplexed compensation capacitor branch corresponding to the target modulation depth from the n multiplexed compensation capacitor branches, and then control the multiplexed compensation capacitor circuit 31 to continuously turn these target multiplexed compensation capacitor branches on and off, so as to continuously switch the corresponding target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor C2, adjust the compensation capacitor value of the receiving end, thereby changing the impedance characteristics of the receiving end, realizing the adjustment of the receiving end impedance, and completing the modulation of the receiving end signal.

[0087] During the non-communication modulation phase after the wireless charging receiver circuit is powered on, the modulation and control circuit 33 can control all the multiplexed compensation capacitors of the multiplexed compensation capacitor circuit 31 to be connected in parallel across the two ends of the receiver compensation capacitor C2. This allows the wireless charging system to enter its optimal resonance state, achieving the highest energy transfer efficiency.

[0088] When the wireless charging receiver circuit is not powered on, all the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are disconnected from the receiver compensation capacitor C2.

[0089] In one embodiment of this application, based on Figure 6 , Figure 7 This is a second schematic diagram of the wireless charging system provided in an embodiment of this application, with reference to... Figure 7 As shown, the wireless charging system may include a wireless charging transmitter circuit 61 and a wireless charging receiver circuit 62.

[0090] The wireless charging transmitter circuit 61 may include a DC power supply Vin, an inverter bridge circuit 611, a transmitter compensation capacitor C1, a transmitter coil L1, a detection circuit 612, a demodulation circuit 613, and a transmitter controller 614. The inverter bridge circuit 611 includes a first inverter bridge switch S1, a second inverter bridge switch S2, a third inverter bridge switch S3, and a fourth inverter bridge switch S4. The drains of the first inverter bridge switch S1 and the third inverter bridge switch S3 are connected to the positive terminal of the DC power supply Vin. The sources of the second inverter bridge switch S2 and the fourth inverter bridge switch S4 are connected to the first ground GND1. The source of the first inverter bridge switch S1 and the drain of the second inverter bridge switch S2 are connected. The source of the third inverter bridge switch S3 and the drain of the fourth inverter bridge switch S4 are connected. In this circuit, the first inverter bridge switch S1 and the second inverter bridge switch S2 are connected in series to form the first bridge arm of the inverter bridge circuit 611, and the third inverter bridge switch S3 and the fourth inverter bridge switch S4 are connected in series to form the second bridge arm of the inverter bridge circuit 611. The transmitter compensation capacitor C1 and the transmitter coil L1 are connected in series between the midpoint B1 of the first bridge arm and the midpoint B2 of the second bridge arm.

[0091] The wireless charging receiver circuit 62 may include a receiving coil L2, a receiving compensation capacitor C2, a multiplexed compensation capacitor circuit 31, a synchronous rectification circuit 32, an output capacitor C0, and a modulation and control circuit 33. The modulation and control circuit 33 may include a modulation circuit 331 and a receiver controller 332. The first output terminal P3 of the receiver controller 332 is connected to the input terminal of the modulation circuit 331. The second output terminal of the receiver controller 332 serves as the second control terminal P2 of the modulation and control circuit 33 and is connected to the controlled terminal of the synchronous rectification circuit 32. The first output terminal of the modulation circuit 331 serves as the first control terminal P1 of the modulation and control circuit 33 and is connected to the controlled terminal of the multiplexed compensation capacitor circuit 31.

[0092] The multiplexed compensation capacitor circuit 31 may include a first multiplexed compensation capacitor branch 311, a second multiplexed compensation capacitor branch 312, ... and an nth multiplexed compensation capacitor branch 31n, for a total of n multiplexed compensation capacitor branches. The first multiplexed compensation capacitor branch 311 includes a first multiplexed compensation capacitor CM1 and a first switch SM1, the second multiplexed compensation capacitor branch 312 includes a second multiplexed compensation capacitor CM2 and a second switch SM2, ..., and the nth multiplexed compensation capacitor branch 31n includes an nth multiplexed compensation capacitor CMn and an nth switch SMn. One of the output sub-terminals of the first output terminal of the modulation circuit 331 is connected as a control sub-terminal of the first control terminal P1 of the modulation and control circuit 33 to the controlled terminal of a switch in the multiplexing compensation capacitor circuit 31. For example, the first output sub-terminal of the first output terminal of the modulation circuit 331 is connected as the first control sub-terminal P11 of the modulation and control circuit 33 to the gate (i.e., the controlled terminal) of the first switch SM1, the second output sub-terminal of the first output terminal of the modulation circuit 331 is connected as the second control sub-terminal P12 of the modulation and control circuit 33 to the gate (i.e., the controlled terminal) of the second switch SM2, ..., the nth output sub-terminal of the first output terminal of the modulation circuit 331 is connected as the nth control sub-terminal P1n of the modulation and control circuit 33 to the gate (i.e., the controlled terminal) of the nth switch SMn.

[0093] The synchronous rectification circuit 32 can be an H-bridge type bridge rectifier circuit. Specifically, the synchronous rectification circuit 32 includes a first rectifier switch SR1, a second rectifier switch SR2, a third rectifier switch SR3, and a fourth rectifier switch SR4. The drains of the first rectifier switch SR1 and the third rectifier switch SR3 are connected and serve as the positive output terminal of the wireless charging receiver circuit 62. The sources of the second rectifier switch SR2 and the fourth rectifier switch SR4 are connected to the second ground GND2. The first rectifier switch SR1 and the second rectifier switch SR2 are connected in series to form the first bridge arm of the synchronous rectification circuit 32, and the third rectifier switch SR3 and the fourth rectifier switch SR4 are connected in series to form the second bridge arm of the synchronous rectification circuit 32. One end of the receiving coil L2 is connected to the first input terminal H1 of the synchronous rectification circuit 32 (i.e., the midpoint H1 of the first bridge arm of the synchronous rectification circuit 32) through the receiving end compensation capacitor C2. The other end of the receiving coil L2 is connected to the second input terminal H2 of the synchronous rectification circuit 32 (i.e., the midpoint H2 of the second bridge arm of the synchronous rectification circuit 32). The output capacitor C0 is connected between the positive output terminal and the negative output terminal of the synchronous rectification circuit 32. The negative output terminal is connected to the second ground GND2. The output terminal of the synchronous rectification circuit 32 is connected to the load RL as the output terminal of the wireless charging receiver circuit 62.

[0094] The wireless charging transmitter circuit 61 and the wireless charging receiver circuit 62 are coupled through the transmitting coil L1 and the receiving coil L2, where k represents the coupling coefficient.

[0095] For example, the first inverter bridge switch S1, the second inverter bridge switch S2, the third inverter bridge switch S3, and the fourth inverter bridge switch S4 in the inverter bridge circuit 611 can be switches with anti-parallel diodes, such as N-type MOS transistors with anti-parallel diodes.

[0096] For example, the first rectifier switch SR1, the second rectifier switch SR2, the third rectifier switch SR3 and the fourth rectifier switch SR4 in the synchronous rectifier circuit 32 can be switches with anti-parallel diodes, such as N-type MOS transistors with anti-parallel diodes.

[0097] according to Figure 7In the wireless charging system shown, the DC power supply Vin of the wireless charging transmitter circuit 61 can provide energy. The DC voltage provided by Vin is converted into AC power by the inverter bridge circuit 611, which drives the resonant circuit composed of the transmitter compensation capacitor C1 and the transmitter coil L1 to generate a high-frequency magnetic field. According to the law of electromagnetic induction, the receiver coil L2 of the wireless charging receiver circuit 62 can induce a high-frequency AC power. This high-frequency AC power enters the synchronous rectification circuit 32 after passing through the receiver compensation capacitor C2. Under the control of the modulation and control circuit 33, the synchronous rectification circuit 32 can rectify the high-frequency AC power to obtain DC power, and then output the rectified DC power to the load RL connected to the synchronous rectification circuit 32.

[0098] In the initial stage when the wireless charging receiver circuit 62 enters the magnetic field of the wireless charging transmitter circuit 61, such as when the device being charged at the receiver touches the wireless charger or charging platform, since the wireless charging receiver circuit 62 is not powered, none of the multiplexed compensation capacitor branches in the multiplexed compensation capacitor circuit 31 of the wireless charging receiver circuit 62 are connected to the circuit. That is, none of the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are connected to the circuit. The compensation capacitor value of the receiver is less than the design value determined according to the resonant compensation capacitor parameters of the receiver. At this time, the gain of the wireless charging system is greater than the gain when all the multiplexed compensation capacitors in the multiplexed compensation capacitor circuit 31 are connected, which is beneficial to the rapid power-on of the receiver.

[0099] After the receiver is powered on, the modulation and control circuit 33 controls all the switching transistors in the multiplexing compensation capacitor circuit 31 to be turned on, and all the multiplexing compensation capacitors in the multiplexing compensation capacitor circuit 31 are connected to the system. The system enters the optimal resonance state, at which time the system can achieve the highest efficiency.

[0100] When the receiver and transmitter begin communication, during the communication modulation stage, the modulation and control circuit 33 determines the actual target modulation depth based on the load power between the positive and negative output terminals of the synchronous rectifier circuit 32. Based on the actual target modulation depth, it determines the target multiplexing compensation capacitor in the multiplexing compensation capacitor circuit 31 that needs to perform modulation. For example, if the first multiplexing compensation capacitor CM1 needs to be used as the modulation capacitor to modulate the signal to be transmitted, the modulation and control circuit 33 controls the other switches in the multiplexing compensation capacitor circuit 31, except for the first switching transistor SM1, to remain in the conducting state, and controls the first switching transistor SM1 to continuously turn on and off, so as to continuously switch the first multiplexing compensation capacitor CM1 into and out of the circuit, thereby adjusting the impedance of the receiver and completing the modulation of the signal with the required target modulation depth.

[0101] During the process of transmitting information from the receiver to the transmitter, the receiver controller 332 can send the signal to be transmitted carrying information to the modulation circuit 331 for encoding. The modulation circuit 331 loads the encoded signal to be transmitted into the energy transmission channel. Under the control of the modulation and control circuit 33, the multiplexing compensation capacitor circuit 31 modulates the signal to be transmitted loaded into the energy transmission channel by cutting in and out multiplexing compensation capacitors that match the required modulation depth, thereby obtaining the modulated and encoded signal to be transmitted. Then, the system uses the electromagnetic field coupling between the wireless charging transmitter circuit 61 and the wireless charging receiver circuit 62 to send the modulated and encoded signal to be transmitted to the wireless charging transmitter circuit 61. The detection circuit 612 in the wireless charging transmitter circuit 61 can detect the modulated and encoded signal to be transmitted transmitted by the wireless charging receiver circuit 62 from the resonant cavity of the wireless charging transmitter circuit 61. The demodulation circuit 613 demodulates the modulated and encoded signal to be transmitted and sends it to the transmitter controller 614. The transmitter controller 614 decodes the demodulated signal to obtain the original signal to be transmitted. The signal to be transmitted carries information transmitted from the receiver to the transmitter, such as at least one of the following: the receiver's address information, negotiation information, collected voltage information, and current information, but not limited to these, thereby realizing information transmission from the receiver to the transmitter.

[0102] After the communication modulation stage is completed, the system enters the energy transmission stage. At this time, the modulation and control circuit 33 controls all the switching transistors in the multiplexing compensation capacitor circuit 31 to always remain in the conducting state, so that all the multiplexing compensation capacitors are always connected to the circuit, ensuring that the system works in the optimal resonance state.

[0103] The wireless charging system provided in this application, during the communication modulation stage, no longer relies on additional modulation capacitors occupying PCB space and high-energy-consuming load resistors for signal modulation. Instead, it employs a scheme where compensation capacitors are reused as modulation capacitors. The target multiplexed compensation capacitors to be modulated in the multiplexed compensation capacitor circuit are determined according to the actual required target modulation depth, and the switching in and out of these target multiplexed compensation capacitors is controlled to adjust the impedance of the receiving end and complete the modulation of the receiving signal. It can reuse the resonant compensation capacitor at the receiving end as a modulation capacitor, using changes in capacitance to alter the impedance characteristics of the receiving end. Compared to related technologies that use modulation resistors at the output end for impedance modulation, it consumes less energy, effectively reducing the energy consumption of the wireless charging system, improving system efficiency, and reducing system heat generation. Furthermore, once the operating frequency and coupling parameters of a wireless charging system are determined, the parameters of its receiver's resonant compensation capacitor (i.e., the compensation capacitor value of the receiver) are also determined. It is usually difficult to find an existing capacitor that corresponds to the compensation capacitor value of the receiver. Therefore, it is necessary to combine multiple different capacitors. In practical applications, regardless of the application design, sufficient space must be reserved for the compensation capacitor. Therefore, using a compensation capacitor reuse scheme to achieve impedance adjustment at the receiver will not occupy additional PCB space, which is beneficial for high-density design and effectively saves system cost.

[0104] This application also provides a chip that includes the wireless charging transmitter circuit provided in any of the above embodiments. During the communication modulation stage, this chip can determine the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit connected in parallel across the receiver compensation capacitor according to the actual required target modulation depth. It then controls the switching in and out of these target multiplexed compensation capacitors to adjust the receiver impedance and complete the modulation of the receiver signal. It can reuse the receiver's resonant compensation capacitor as a modulation capacitor, using changes in capacitance to alter the receiver's impedance characteristics. Compared to related technologies that use the modulation resistor at the output end for impedance modulation, it consumes less energy, effectively reducing the power consumption of the wireless charging system, improving system efficiency, and reducing system heat generation. Furthermore, using a multiplexed compensation capacitor scheme to achieve receiver impedance adjustment does not occupy additional PCB space, which is beneficial for high-density design and effectively reduces costs.

[0105] This application also provides an electronic device, which includes a wireless charging transmitter circuit as described in any of the above embodiments, or includes the chip described above. This electronic device is an electronic device on the charging side, has wireless charging functionality, and may include at least one of the following: mobile phone, wearable device, laptop, tablet, wireless headset, in-vehicle device, smart home device, virtual reality (VR) terminal device, and augmented reality (AR) terminal device, but is not limited thereto. This electronic device can determine the target multiplexed compensation capacitor to be modulated in the multiplexed compensation capacitor circuit connected in parallel across the receiving end compensation capacitor according to the actual required target modulation depth during the communication modulation stage, and control the switching in and out of these target multiplexed compensation capacitors to adjust the impedance of the receiving end, thereby completing the modulation of the receiving end signal. It can reuse the resonant compensation capacitor of the receiving end as a modulation capacitor, using changes in capacitance value to change the impedance characteristics of the receiving end. Compared with the related technology scheme that uses the modulation resistor at the output end for impedance modulation, it consumes less energy, effectively reducing the energy consumption of the wireless charging system, improving system efficiency, and reducing system heat generation. Moreover, using a compensation capacitor reuse scheme to achieve impedance adjustment at the receiver does not occupy additional PCB space, which is beneficial for high-density design and effectively reduces costs.

[0106] In one embodiment of this application, the electronic device may include a processor, an external memory interface, internal memory, a Universal Serial Bus (USB) interface, a charging management module, a power management module, a battery, an antenna, a mobile communication module, a wireless communication module, an audio module, a speaker, a microphone, a headphone jack, a sensor module, buttons, a motor, an indicator, a camera, a display screen, and a Subscriber Identification Module (SIM) card interface, etc. The sensor module may include motion sensors and gyroscopes, etc.

[0107] It is understood that the structures exemplified in the embodiments of this application do not constitute a specific limitation on the electronic device. In other embodiments of this application, the electronic device may include more or fewer components, or combine some components, or split some components, or have different component arrangements. These components may be implemented in hardware, software, or a combination of software and hardware.

[0108] The processor may include one or more processing units, such as, but not limited to, an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and a neural network processing unit (NPU). Different processing units may be independent devices or integrated into one or more processors. The controller can generate operation control signals based on instruction opcodes and timing signals to control instruction fetching and execution. The processor may also include memory for storing instructions and data. In some embodiments, the memory in the processor may be a cache memory. This memory can store instructions or data that the processor has just used or that are used repeatedly. If the processor needs to reuse the instruction or data, it can retrieve it from memory. This avoids repeated accesses, reduces processor waiting time, and thus improves system efficiency.

[0109] The charging management module receives charging signals from a charger, which may include a wireless charger. In some wireless charging embodiments, the charging management module includes a wireless charging receiver circuit, which receives wireless charging input through its receiving coil. While charging the battery, the charging management module can also supply power to the electronic device via the power management module.

[0110] The power management module connects the battery, the charging management module, and the processor. It receives input from the battery and / or the charging management module to power the processor, internal memory, display screen, camera, and wireless communication module. The power management module can also monitor parameters such as battery capacity, battery cycle count, and battery health status (leakage current, impedance). In some embodiments, the power management module may be located within the processor. In other embodiments, the power management module and the charging management module may be located in the same device.

[0111] Wireless communication functionality in electronic devices can be implemented through antennas, mobile communication modules, wireless communication modules, modem processors, and baseband processors. Antennas are used to transmit and receive electromagnetic wave signals. Mobile communication modules can provide solutions for wireless communication applications in electronic devices, including 2G / 3G / 4G / 5G. In some embodiments, at least some functional modules of the mobile communication module can be housed in the same device as at least some modules of the processor.

[0112] Wireless communication modules can provide solutions for at least one of the following wireless communication technologies used in electronic devices: Wireless Local Area Networks (WLANs) (such as Wireless Fidelity (Wi-Fi) networks), Bluetooth (BT), Global Navigation Satellite System (GNSS), Frequency Modulation (FM), Near Field Communication (NFC), and Infrared (IR), but are not limited to these. A wireless communication module can be one or more devices integrating at least one communication processing module. The wireless communication module receives electromagnetic waves via an antenna, modulates and filters the electromagnetic wave signal, and sends the processed signal to a processor. The wireless communication module can also receive signals to be transmitted from the processor, modulate and amplify them, and then radiate them as electromagnetic waves via the antenna.

[0113] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations thereof that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

Claims

1. A wireless charging receiver circuit, characterized in that, It includes a receiving coil, a receiving end compensation capacitor, a multiplexing compensation capacitor circuit, a synchronous rectification circuit, an output capacitor, and a modulation and control circuit; One end of the receiving coil is connected to the first input terminal of the synchronous rectification circuit through the receiving end compensation capacitor, and the other end of the receiving coil is connected to the second input terminal of the synchronous rectification circuit. The output capacitor is connected between the positive output terminal and the negative output terminal of the synchronous rectification circuit. The multiplexing compensation capacitor circuit is connected in parallel across the two ends of the receiving end compensation capacitor, and the controlled end of the multiplexing compensation capacitor circuit is connected to the first control end of the modulation and control circuit, and the second control end of the modulation and control circuit is connected to the controlled end of the synchronous rectification circuit. The modulation and control circuit is used to determine the target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit according to the target modulation depth during the communication modulation stage, and to control the multiplexing compensation capacitor circuit to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor; wherein, the target modulation depth is determined based on the load power between the positive output terminal and the negative output terminal of the synchronous rectification circuit.

2. The wireless charging receiver circuit according to claim 1, characterized in that, The multiplexing compensation capacitor circuit includes at least one multiplexing compensation capacitor branch, and each multiplexing compensation capacitor branch includes a multiplexing compensation capacitor and a switching transistor; The first terminal of the multiplexing compensation capacitor is connected to the first terminal of the receiving compensation capacitor, and the second terminal of the multiplexing compensation capacitor is connected to the second terminal of the receiving compensation capacitor through the switching transistor. The controlled terminal of the switching transistor is connected to one of the controlled sub-terminals of the multiplexing controlled terminal of the multiplexing compensation capacitor circuit and one of the control sub-terminals of the first control terminal of the modulation and control circuit. The modulation and control circuit controls the switching transistors corresponding to each multiplexed compensation capacitor in the target multiplexed compensation capacitor to turn the target multiplexed compensation capacitor into and out of the two ends of the receiving end compensation capacitor by controlling the switching transistors to turn on and off.

3. The wireless charging receiver circuit according to claim 2, characterized in that, The modulation and control circuit includes a modulation circuit and a receiver controller; The first output terminal of the receiver controller is connected to the input terminal of the modulation circuit. The second output terminal of the receiver controller is connected to the controlled terminal of the synchronous rectification circuit as the second control terminal of the modulation and control circuit. The first output terminal of the modulation circuit is connected to the controlled terminal of the multiplexed compensation capacitor circuit as the first control terminal of the modulation and control circuit. Furthermore, one output sub-terminal of the first output terminal of the modulation circuit is connected to the controlled terminal of one of the switching transistors in the multiplexed compensation capacitor circuit as a control sub-terminal of the first control terminal of the modulation and control circuit. The receiver controller is used to determine the target modulation depth of the signal to be transmitted based on the load power of the synchronous rectifier circuit during the communication modulation stage, and generate a multiplexing capacitor control signal based on the target modulation depth and send it to the modulation circuit; the multiplexing capacitor control signal is used to indicate the target multiplexing compensation capacitor branch to be modulated in the multiplexing compensation capacitor circuit. The modulation circuit amplifies the power of the multiplexed capacitor control signal to obtain a switching transistor drive signal, and sends the switching transistor drive signal to the multiplexed compensation capacitor circuit to control the switching transistors of each multiplexed compensation capacitor branch in the target multiplexed compensation capacitor branch to continuously turn on and off.

4. The wireless charging receiver circuit according to any one of claims 1 to 3, characterized in that, The greater the load power, the greater the capacitance value of the target multiplexing compensation capacitor cut off from both ends of the receiving end compensation capacitor by the multiplexing compensation capacitor circuit.

5. The wireless charging receiver circuit according to any one of claims 1 to 3, characterized in that, The modulation and control circuit is also used to control all the multiplexing compensation capacitors of the multiplexing compensation capacitor circuit to be connected in parallel to the two ends of the receiving compensation capacitor during the non-communication phase after the wireless charging receiver circuit is powered on.

6. The wireless charging receiver circuit according to any one of claims 1 to 3, characterized in that, When the wireless charging receiver circuit is not powered on, all the multiplexing compensation capacitors in the multiplexing compensation capacitor circuit are disconnected from the receiver compensation capacitor.

7. A signal modulation method, characterized in that, Modulation and control circuits applied in wireless charging receiver circuits as described in any one of claims 1 to 6; The signal modulation method includes: During the communication modulation stage, the target modulation depth is determined based on the load power between the positive and negative output terminals of the synchronous rectifier circuit. The target multiplexing compensation capacitor to be modulated in the multiplexing compensation capacitor circuit is determined according to the target modulation depth, and the multiplexing compensation capacitor circuit is controlled to continuously switch the target multiplexing compensation capacitor into and out of the two ends of the receiving end compensation capacitor in order to modulate the signal to be transmitted in the wireless charging receiving end circuit.

8. A wireless charging system, characterized in that, It includes a wireless charging transmitter circuit and a wireless charging receiver circuit as described in any one of claims 1 to 6; the wireless charging transmitter circuit and the wireless charging receiver circuit are coupled through the transmitting coil of the wireless charging transmitter circuit and the receiving coil of the wireless charging receiver circuit.

9. A chip, characterized in that, Includes the wireless charging receiver circuit as described in any one of claims 1 to 6.

10. An electronic device, characterized in that, It includes the wireless charging receiver circuit as described in any one of claims 1 to 6, or the chip as described in claim 9.

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