Synchronous rectification zero-crossing compensation circuit, compensation method, and wireless charging system

Abstract

The application provides a synchronous rectification zero-crossing compensation circuit, a compensation method and a wireless charging system, relates to the technical field of wireless charging, and can realize adaptive compensation following the voltage change rate in real time, thereby avoiding the problems of under-compensation or over-compensation caused by dynamic changes of a load end, and simultaneously has better adaptability and more stable and reliable compensation performance.

Description

Technical Field

[0001] This invention relates to the technical field of wireless charging, and in particular to a synchronous rectification zero-crossing compensation circuit, compensation method, and wireless charging system. Background Technology

[0002] In traditional wireless charging systems, the synchronous rectification zero-crossing compensation circuit at the receiver typically uses compensation resistors and additional input compensation current for compensation. While compensation can advance the comparator's threshold flip compared to no compensation, in actual wireless charging system operation, the load current often changes after the receiver is connected to a load, causing the input current slope to change in real time. This change necessitates a corresponding change in the load resistance required for compensation. However, in practice, it is difficult to achieve real-time changes in the compensation resistor value with the current slope, leading to untimely dynamic compensation and resulting in undercompensation or overcompensation, thus reducing the stability of the wireless charging system. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a synchronous rectification zero-crossing compensation circuit, a compensation method, and a wireless charging system to alleviate the above-mentioned technical problems.

[0004] In a first aspect, embodiments of the present invention provide a synchronous rectification zero-crossing compensation circuit applied to the receiver of a wireless charging system, wherein the receiver is provided with a synchronous rectification bridge circuit; the synchronous rectification zero-crossing compensation circuit includes: a sampling compensation module and a comparator connected to the sampling compensation module; wherein the sampling compensation module is connected between the input terminal of the synchronous rectification bridge circuit and the input terminal of the comparator; the output terminal of the comparator is connected to the controller of the wireless charging system; the sampling compensation module includes a sampling capacitor and a compensation resistor; the sampling compensation module collects the AC input at the input terminal of the synchronous rectification bridge circuit through the sampling capacitor. The voltage change rate of the signal is measured and converted into a current signal; the current signal is converted into a compensation signal through the compensation resistor and superimposed on the zero-crossing detection signal; the zero-crossing detection signal is input to the comparator, and when the zero-crossing detection signal reaches a preset flip threshold, the comparator is triggered to flip, generating a flip signal, which is sent to the controller so that the controller can turn off or turn on the switching transistor in the synchronous rectifier bridge circuit in advance based on the flip signal, and the advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

[0005] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the sampling compensation module includes a first sampling branch and a second sampling branch connected in parallel; the first sampling branch includes the sampling capacitor and the conversion circuit connected in sequence; the sampling capacitor is used to collect the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit; the conversion circuit is used to convert the voltage change rate into a current signal; the second sampling branch includes the compensation resistor, the compensation resistor is used to convert the current signal into a compensation signal, and superimpose the compensation signal onto the zero-crossing detection signal.

[0006] In conjunction with the first possible implementation of the first aspect, this embodiment of the invention provides a second possible implementation of the first aspect, wherein the conversion circuit includes an operational amplifier and an output transistor; wherein one end of the sampling capacitor is connected to the input terminal of the synchronous rectifier bridge circuit, and the other end is connected to the operational amplifier and the output transistor; the input terminal of the operational amplifier is connected to the other end of the sampling capacitor, and the output terminal is connected to the control terminal of the output transistor, and the operational amplifier is configured to clamp or follow the other end of the sampling capacitor; one end of the output transistor is connected to the input terminal of the sampling capacitor and the operational amplifier, and the other end of the output transistor is connected to the input pin of the comparator, for converting the signal sampled by the sampling capacitor into the current signal.

[0007] In conjunction with the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the capacitance value of the sampling capacitor and the resistance value of the compensation resistor are determined by the delay parameters of the synchronous rectification zero-crossing compensation circuit, and the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor is configured to match the delay time of the synchronous rectification zero-crossing compensation circuit.

[0008] In conjunction with the second possible implementation of the first aspect, this embodiment of the invention provides a fourth possible implementation of the first aspect, wherein the output transistor includes a P-type MOS transistor, the gate of the P-type MOS transistor is connected to the output terminal of the operational amplifier, the source is connected to the other end of the sampling capacitor, and the drain is connected to the input terminal of the comparator.

[0009] In conjunction with the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein the above-mentioned synchronous rectifier bridge circuit includes two input terminals, and each input terminal is provided with the synchronous rectification zero-crossing compensation circuit.

[0010] Secondly, embodiments of the present invention also provide a wireless charging system, wherein the receiving end of the wireless charging system is provided with a synchronous rectifier bridge circuit; the synchronous rectifier bridge circuit is configured with a synchronous rectification zero-crossing compensation circuit as described in the first aspect.

[0011] In conjunction with the second aspect, the present invention provides a first possible implementation of the second aspect, wherein the aforementioned synchronous rectifier bridge circuit is a full-bridge rectifier topology, including a first upper switch, a second upper switch, a first lower switch, and a second lower switch; the connection point between the first upper switch and the first lower switch, and the connection point between the second upper switch and the second lower switch, are respectively the input terminals of the synchronous rectifier bridge circuit; each input terminal is configured with a synchronous rectification zero-crossing compensation circuit, used to independently compensate for the zero-crossing point of the input terminal of the synchronous rectifier bridge circuit.

[0012] Thirdly, embodiments of the present invention also provide a synchronous rectification zero-crossing compensation method, applied to the receiver of a wireless charging system, wherein the receiver is provided with a synchronous rectification bridge circuit; the synchronous rectification bridge circuit is provided with a synchronous rectification zero-crossing compensation circuit of the first aspect; the method includes: acquiring the voltage change rate of the AC signal input to the input terminal of the synchronous rectification bridge circuit in real time through a sampling capacitor; converting the voltage change rate into a current signal; converting the current signal into a compensation signal through a compensation resistor, and superimposing the compensation signal onto a zero-crossing detection signal; when the zero-crossing detection signal reaches a preset flip threshold, triggering a comparator to flip, generating a flip signal, and sending the flip signal to a controller so that the controller turns off or turns on the switching transistor in the synchronous rectification bridge circuit in advance, wherein the advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

[0013] In conjunction with the third aspect, the present invention provides a first possible implementation of the third aspect, wherein the method further includes: obtaining delay parameters of the wireless charging system, wherein the delay parameters include at least the delay parameters of the controller, the delay parameters of the sampling compensation module, and the delay parameters of the synchronous rectifier bridge circuit; setting the capacitance value of the sampling capacitor and the resistance value of the compensation resistor based on the delay parameters of the wireless charging system, so that the advance amount by which the controller turns off or turns on the switching transistor in the synchronous rectifier bridge circuit in advance offsets the signal transmission delay caused by the delay parameters.

[0014] The embodiments of the present invention bring the following beneficial effects: This invention provides a synchronous rectification zero-crossing compensation circuit, compensation method, and wireless charging system. A sampling compensation module is connected between the input terminal of the synchronous rectifier bridge circuit and the input terminal of a comparator. The output terminal of the comparator is connected to the controller of the wireless charging system. The sampling compensation module includes a sampling capacitor and a compensation resistor. The sampling compensation module acquires the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit through the sampling capacitor and converts the voltage change rate into a current signal. The compensation resistor converts the current signal into a compensation signal, which is then superimposed on the zero-crossing detection signal. The zero-crossing detection signal is input to the comparator. When the zero-crossing detection signal reaches a preset flip threshold, it triggers the comparator to flip, generating a flip signal. This flip signal is sent to the controller, allowing the controller to turn off or turn on the switching transistors in the synchronous rectifier bridge circuit in advance based on the flip signal. The advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor. Since the compensation signal is based on the acquired voltage change rate, it can achieve real-time adaptive compensation following the voltage change rate, thereby avoiding undercompensation or overcompensation caused by dynamic changes in the load. It also has better adaptability and more stable and reliable compensation performance.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A structural block diagram of a synchronous rectification zero-crossing compensation circuit provided in an embodiment of the present invention; Figure 2 A circuit diagram of a synchronous rectification zero-crossing compensation circuit provided for an embodiment of the present invention; Figure 3 A flowchart of a synchronous rectification zero-crossing compensation method provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In traditional wireless charging systems, compensation resistors and current compensations are typically introduced at the input of the synchronous rectifier bridge circuit at the receiver to compensate for the fixed delay in the system. This compensation allows the voltage at the input of the comparator in the circuit to reach the flip threshold earlier; that is, compared to the uncompensated state, the comparator's flip threshold is earlier. This allows the controller to adjust the rectification timing of the synchronous rectifier bridge circuit earlier based on the earlier flip signal, thereby reducing delay. The amount of advance in flipping is usually related to the change in current at the input of the synchronous rectifier bridge circuit and the resistance value of the compensation resistor. However, in practical applications, the load current often changes after the receiver is connected. This causes the current slope K at the input of the synchronous rectifier bridge circuit to change in real time with the load current. However, the resistance value of the compensation resistor is difficult to select to keep pace with the real-time changes in the current slope. Consequently, when the system load changes dynamically, the compensation may not keep up with the changes, ultimately leading to undercompensation or overcompensation, reducing the stability and efficiency of the wireless charging system.

[0021] Based on this, the synchronous rectification zero-crossing compensation circuit, compensation method, and wireless charging system provided in this embodiment of the invention can directly collect the above-mentioned rate of change, realize an adaptive compensation method, and thus alleviate the above-mentioned technical problems.

[0022] To facilitate understanding of this embodiment, a synchronous rectification zero-crossing compensation circuit disclosed in this embodiment of the invention will first be described in detail.

[0023] In one possible implementation, this invention provides a synchronous rectification zero-crossing compensation circuit applied to the receiver of a wireless charging system. The receiver includes a synchronous rectification bridge circuit. Specifically, the receiver further includes a receiving coil and a resonant circuit connected to the receiving coil to receive the electrical signal coupled from the transmitting end, thereby generating an AC signal at the receiver. This AC signal enters the synchronous rectification bridge circuit through its input terminal, is rectified into DC, and then supplied to the subsequent load. The synchronous rectification zero-crossing compensation circuit in this invention aims to solve the problem of undercompensation or overcompensation that traditional compensation circuits easily exhibit when the load dynamically changes.

[0024] Specifically, such as Figure 1The diagram shows a structural block diagram of a synchronous rectification zero-crossing compensation circuit. In this embodiment of the invention, the synchronous rectification zero-crossing compensation circuit includes: a sampling compensation module 10 and a comparator 20 connected to the sampling compensation module 10; wherein, the sampling compensation module 10 is connected between the input terminal of the synchronous rectification bridge circuit and the input terminal of the comparator; the output terminal of the comparator is connected to the controller of the wireless charging system.

[0025] The sampling compensation module 10 includes a sampling capacitor 101 and a compensation resistor 102. The sampling compensation module uses the sampling capacitor 101 to acquire the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit and converts this voltage change rate into a current signal. It also uses the compensation resistor 102 to convert the current signal into a compensation signal and superimposes the compensation signal onto the zero-crossing detection signal. This zero-crossing detection signal is input to the comparator 20. When the zero-crossing detection signal reaches a preset flip threshold, it triggers the comparator 20 to flip, generating a flip signal. This flip signal is sent to the controller, allowing the controller to turn off or turn on the switching transistors in the synchronous rectifier bridge circuit in advance based on the flip signal. The advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor 101 and the resistance value of the compensation resistor 102.

[0026] In practical use, the sampling capacitor mentioned above collects the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit, which is actually caused by the current change rate flowing into the receiving coil of the receiving end. This current change rate is also called the slope. In this embodiment of the invention, the slope can be sampled directly, and the compensation signal obtained therefrom can follow the slope, thereby realizing real-time adaptive compensation by following the voltage change rate, and avoiding the problem of undercompensation or overcompensation caused by dynamic changes at the load end. It also has better adaptability and more stable and reliable compensation performance.

[0027] Furthermore, for ease of understanding, in the above... Figure 1 On this basis, Figure 2 A circuit diagram of a synchronous rectification zero-crossing compensation circuit is also shown, and, for ease of explanation, Figure 2 The diagram also shows a partial schematic of a synchronous rectifier bridge circuit. Specifically, as shown... Figure 2 As shown in the embodiment of the present invention, the sampling compensation module includes a first sampling branch and a second sampling branch connected in parallel; wherein, the first sampling branch includes a sampling capacitor Cs and a conversion circuit connected in sequence; the sampling capacitor Cs is used to collect the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit; wherein, in this embodiment of the present invention, taking one of the input terminals AC1 of the synchronous rectifier bridge circuit as an example, the conversion circuit is used to convert the voltage change rate into a current signal; the second sampling branch includes a compensation resistor RL, which is used to convert the current signal into a compensation signal and superimpose the compensation signal onto the zero-crossing detection signal.

[0028] In a specific implementation, the conversion circuit in this embodiment of the invention includes an operational amplifier AMP and an output transistor P1; wherein, one end of the sampling capacitor Cs is connected to the input terminal AC1 of the synchronous rectifier bridge circuit, and the other end is connected to the operational amplifier AMP and the output transistor P1; the input terminal of the operational amplifier AMP is connected to the other end of the sampling capacitor Cs, and the output terminal is connected to the control terminal of the output transistor P1, and the operational amplifier AMP is configured to clamp or follow the other end of the sampling capacitor Cs; one end of the output transistor P1 is connected to the input terminal of the sampling capacitor Cs and the operational amplifier AMP, and the other end of the output transistor P1 is connected to the input pin of the comparator C1, which is used to convert the signal sampled by the sampling capacitor Cs into a current signal.

[0029] Furthermore, in this embodiment of the invention, the capacitance value of the sampling capacitor Cs and the resistance value of the compensation resistor PL are determined by the delay parameters of the synchronous rectification zero-crossing compensation circuit, and the product of the capacitance value of the sampling capacitor Cs and the resistance value of the compensation resistor is configured to match the delay time of the synchronous rectification zero-crossing compensation circuit.

[0030] In practical implementation, since the two input terminals AC1 and AC2 of the synchronous rectifier bridge circuit are symmetrical, that is, the synchronous rectifier bridge circuit includes two input terminals, each input terminal in this embodiment of the invention is provided with a synchronous rectification zero-crossing compensation circuit. For ease of explanation, this embodiment of the invention uses input terminal AC1 as an example; in actual circuit operation, the same compensation circuit will be implemented on both AC1 and AC2.

[0031] For ease of understanding, the following is combined with Figure 2 The working principle of the synchronous rectification zero-crossing compensation circuit in the embodiments of the present invention will be explained.

[0032] In practical implementation, the receiving coil L can receive the electrical signal coupled from the transmitting end. The capacitor C is the coupling capacitor of the receiving coil L. A sampling circuit is formed by combining the sampling capacitor Cs, the operational amplifier AMP, and the output transistor P1. During operation, the operational amplifier AMP clamps one end of the sampling capacitor Cs, so the other end of the sampling capacitor Cs can sample the voltage of the input terminal AC1 and obtain the sampling current. This sampling current is expressed as: Is= *Cs, where AC1 represents the AC signal input at the input terminal; and this AC can also be expressed as: AC1=Icoil*Rds_LS1, where Icoil represents the current of the receiving coil L, also known as the coil current, and Rds_LS1 represents the drain-source on-resistance of the lower-side switch LS1 (i.e., the low-side switch) in the on-state. At this time, the sampling current Is can be related to the current Icoil of the receiving coil L, so that Is contains the slope information K of the current of the receiving coil, that is, the derivation formula is as follows: = =K* Rds_LS1.

[0033] Therefore, the K-factor sampled current Is can be used to offset the K-factor coil current Icoil, achieving adaptive compensation of the system. The specific derivation formula is as follows: The input of comparator C1 is Vp = Is * RL + AC1 = When comparator C1 flips (*Cs*RL+AC1), Vp=0V, meaning the reference voltage of comparator C1 is 0V. Therefore, we have: *Cs*RL+AC1=0, As mentioned above, AC1 = Icoil * Rds_LS1. = =K*Rds_LS1, therefore, K is the slope information of the coil current, and AC1 and Substituting into the above equation, we get: K* Rds_LS1*Cs*RL+ Icoil*Rds_LS1=0, Assuming the delay parameter from the comparator to the subsequent circuit is T_delay, and the slope information of the coil current is known as K, then after time T, the change in coil current is K*T_delay. Therefore, the current to be compensated is K*T_delay. Thus, the final compensation formula is as follows: K* Rds_LS1*Cs*RL-K*T_delay*Rds_LS1=0. After canceling out the common factors, we get T_delay=Cs*RL. Therefore, the delay parameter T_delay can be compensated by the fixed product of the capacitance value of the capacitor Cs and the resistance value of the compensation resistor RL.

[0034] Furthermore, in the above-described scheme of this invention, the sampling circuit is used to sample the change in coil current for dynamic compensation, which achieves real-time compensation following the current slope, realizes adaptive compensation of the system, solves the problem of undercompensation or overcompensation when the load of the wireless charging system changes dynamically, and has better adaptability and more stable and reliable compensation performance in practical applications.

[0035] Furthermore, the aforementioned output transistor includes a P-type MOSFET, i.e. Figure 2 In this example, we will use a P-type MOS transistor as the output transistor. The gate of the P-type MOS transistor is connected to the output terminal of the operational amplifier AMP, the source is connected to the other end of the sampling capacitor, and the drain is connected to the input terminal of the comparator.

[0036] Furthermore, based on the above embodiments, this invention also provides a wireless charging system, wherein the receiver of the wireless charging system is provided with a synchronous rectifier bridge circuit; the synchronous rectifier bridge circuit is configured with the aforementioned synchronous rectification zero-crossing compensation circuit.

[0037] Similarly Figure 2 Taking this as an example, the synchronous rectifier bridge circuit in this embodiment of the invention is a full-bridge rectifier topology, such as... Figure 2 As shown, it includes a first upper switch HS1, a second upper switch HS2, a first lower switch LS1, and a second lower switch LS2; wherein, the upper switch is also called the upper transistor, and the lower switch is also called the lower transistor, and the connection point between the first upper switch and the first lower switch, and the connection point between the second upper switch and the second lower switch, are respectively the input terminals of the synchronous rectifier bridge circuit; that is, Figure 2 AC1 and AC2 are shown in the diagram. Each input terminal is equipped with a synchronous rectification zero-crossing compensation circuit to independently compensate for the zero-crossing point of the input terminal of the synchronous rectifier bridge circuit. Figure 2 The compensation for output AC1 will be explained below.

[0038] In practical use, in the above full-bridge rectifier topology, the first upper switch HS1 and the second lower switch LS2 are simultaneously turned on and off, and the second upper switch HS2 and the first lower switch LS1 are simultaneously turned on and off. Taking the first upper switch HS1 and the second lower switch LS2 forming the first path and the second upper switch HS2 and the first lower switch LS1 forming the second path as an example, the switches of the first path and the second path are in an alternating on-state. That is, when the switch of the first path is on, the switch of the second path is off, and when the switch of the second path is off, the switch of the second path is on. The on or off of the switches of the first path and the second path are alternating, and the on or off of the switches is controlled by the controller. When the controller receives a flip signal, it can control the on or off of the switches. This flip signal can be compensated by the synchronous rectification zero-crossing compensation circuit described in the embodiment of the present invention to solve the problem of undercompensation or overcompensation when the load of the wireless charging system changes dynamically.

[0039] Furthermore, this embodiment of the invention also provides a synchronous rectification zero-crossing compensation method, applied to the receiving end of the aforementioned wireless charging system, wherein the receiving end is provided with a synchronous rectification bridge circuit; the synchronous rectification bridge circuit is provided with the aforementioned synchronous rectification zero-crossing compensation circuit; specifically, as shown... Figure 3 The flowchart shown illustrates a synchronous rectification zero-crossing compensation method, which includes the following steps: Step S302: The voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit is collected in real time through the sampling capacitor; Step S304: Convert the voltage change rate into a current signal; Step S306: Convert the current signal into a compensation signal through a compensation resistor, and superimpose the compensation signal onto the zero-crossing detection signal; Step S308: When the zero-crossing detection signal reaches the preset flip threshold, the comparator is triggered to flip and a flip signal is generated. The flip signal is sent to the controller so that the controller can turn off or turn on the switching transistor in the synchronous rectifier bridge circuit in advance. The advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

[0040] Furthermore, in this embodiment of the invention, the delay parameters of the wireless charging system can be obtained during the design phase or under laboratory conditions. These delay parameters include at least the delay parameters of the controller, the delay parameters of the sampling compensation module, and the delay parameters of the synchronous rectifier bridge circuit. For example, the delay inherent in the controller chip itself, the delay inherent in each switch in the synchronous rectifier bridge circuit, and the delay of the output transistor in the sampling compensation module, etc., all contribute to a fixed delay parameter in the wireless charging system. This delay parameter can be compensated by the synchronous rectification zero-crossing compensation circuit provided in this embodiment of the invention. After obtaining the delay parameters of the wireless charging system, the capacitance value of the sampling capacitor and the resistance value of the compensation resistor can be set based on these parameters. This allows the controller to turn off or turn on the switches in the synchronous rectifier bridge circuit earlier by an amount that offsets the signal transmission delay caused by the delay parameters. In this embodiment of the invention, the advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

[0041] The compensation method and wireless charging system provided in this invention have the same technical features as the synchronous rectification zero-crossing compensation circuit provided in the above embodiments, so they can also solve the same technical problems and achieve the same technical effects.

[0042] The computer program product of the synchronous rectification zero-crossing compensation circuit, compensation method and wireless charging system provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0043] Those skilled in the art will understand that, for the sake of convenience and brevity, the compensation method and the specific working process of the wireless charging system described above can be referred to the corresponding processes in the foregoing embodiments, and will not be repeated here.

[0044] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0045] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0046] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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 the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A synchronous rectification zero-crossing compensation circuit, characterized in that, A receiver for use in a wireless charging system is provided with a synchronous rectification bridge circuit; the synchronous rectification zero-crossing compensation circuit includes: a sampling compensation module and a comparator connected to the sampling compensation module; The sampling compensation module is connected between the input terminal of the synchronous rectifier bridge circuit and the input terminal of the comparator; the output terminal of the comparator is connected to the controller of the wireless charging system. The sampling compensation module includes a sampling capacitor and a compensation resistor; the sampling compensation module acquires the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit through the sampling capacitor, and converts the voltage change rate into a current signal; and converts the current signal into a compensation signal through the compensation resistor, and superimposes the compensation signal onto the zero-crossing detection signal; The zero-crossing detection signal is used as input to the comparator. When the zero-crossing detection signal reaches a preset flip threshold, the comparator is triggered to flip, generating a flip signal. The flip signal is sent to the controller so that the controller can turn off or turn on the switching transistor in the synchronous rectifier bridge circuit in advance based on the flip signal. The advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

2. The synchronous rectification zero-crossing compensation circuit according to claim 1, characterized in that, The sampling compensation module includes a first sampling branch and a second sampling branch connected in parallel. The first sampling branch includes the sampling capacitor and the conversion circuit connected in sequence; the sampling capacitor is used to collect the voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit; The conversion circuit is used to convert the voltage change rate into a current signal; The second sampling branch includes the compensation resistor, which is used to convert the current signal into a compensation signal and superimpose the compensation signal onto the zero-crossing detection signal.

3. The synchronous rectification zero-crossing compensation circuit according to claim 2, characterized in that, The conversion circuit includes an operational amplifier and an output transistor; One end of the sampling capacitor is connected to the input terminal of the synchronous rectifier bridge circuit, and the other end is connected to the operational amplifier and the output transistor. The input terminal of the operational amplifier is connected to the other end of the sampling capacitor, and the output terminal is connected to the control terminal of the output transistor. The operational amplifier is configured to clamp or follow the other end of the sampling capacitor. One end of the output transistor is connected to the sampling capacitor and the input terminal of the operational amplifier, and the other end of the output transistor is connected to the input pin of the comparator, for converting the signal sampled by the sampling capacitor into the current signal.

4. The synchronous rectification zero-crossing compensation circuit according to claim 1, characterized in that, The capacitance value of the sampling capacitor and the resistance value of the compensation resistor are determined by the delay parameters of the synchronous rectification zero-crossing compensation circuit, and the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor is configured to match the delay time of the synchronous rectification zero-crossing compensation circuit.

5. The synchronous rectification zero-crossing compensation circuit according to claim 3, characterized in that, The output transistor includes a P-type MOS transistor, the gate of which is connected to the output terminal of the operational amplifier, the source of which is connected to the other end of the sampling capacitor, and the drain of which is connected to the input terminal of the comparator.

6. The synchronous rectification zero-crossing compensation circuit according to claim 1, characterized in that, The synchronous rectifier bridge circuit includes two input terminals, and each input terminal is provided with a synchronous rectification zero-crossing compensation circuit.

7. A wireless charging system, characterized in that, The receiving end of the wireless charging system is provided with a synchronous rectifier bridge circuit; the synchronous rectifier bridge circuit is configured with the synchronous rectification zero-crossing compensation circuit as described in any one of claims 1 to 6.

8. The wireless charging system according to claim 7, characterized in that, The synchronous rectifier bridge circuit is a full-bridge rectifier topology, including a first upper switch, a second upper switch, a first lower switch, and a second lower switch; the connection point between the first upper switch and the first lower switch, and the connection point between the second upper switch and the second lower switch are respectively the input terminals of the synchronous rectifier bridge circuit. Each of the input terminals is equipped with a synchronous rectification zero-crossing compensation circuit, which is used to independently compensate the zero-crossing point of the input terminal of the synchronous rectification bridge circuit.

9. A synchronous rectification zero-crossing compensation method, characterized in that, A receiver for use in a wireless charging system, wherein the receiver is provided with a synchronous rectifier bridge circuit; the synchronous rectifier bridge circuit is provided with a synchronous rectification zero-crossing compensation circuit as described in any one of claims 1 to 6. The method includes: The voltage change rate of the AC signal input to the input terminal of the synchronous rectifier bridge circuit is collected in real time by sampling capacitor. The voltage change rate is converted into a current signal; The current signal is converted into a compensation signal by a compensation resistor, and the compensation signal is superimposed on the zero-crossing detection signal. When the zero-crossing detection signal reaches the preset flip threshold, the comparator is triggered to flip, generating a flip signal. The flip signal is sent to the controller so that the controller can turn off or turn on the switching transistor in the synchronous rectifier bridge circuit in advance. The advance amount of the controller is determined by the product of the capacitance value of the sampling capacitor and the resistance value of the compensation resistor.

10. The wireless charging system according to claim 9, characterized in that, The method further includes: Obtain the delay parameters of the wireless charging system, wherein the delay parameters include at least the delay parameters of the controller, the delay parameters of the sampling compensation module, and the delay parameters of the synchronous rectifier bridge circuit; Based on the delay parameters of the wireless charging system, the capacitance value of the sampling capacitor and the resistance value of the compensation resistor are set so that the controller can turn off or turn on the switching transistor in the synchronous rectifier bridge circuit in advance to offset the signal transmission delay caused by the delay parameters.

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