Self-adaptive switching circuit for wireless charging and control method

Abstract

The invention discloses a self-adaptive switching circuit for wireless charging and a control method, and relates to the technical field of wireless charging, and the self-adaptive switching circuit for wireless charging comprises a transmitting coil, a first driving loop, a second driving loop, a reconfigurable resonant network, a multiplexing switching module and a control unit. The control unit is used for analyzing a communication protocol of the receiving end equipment to determine a target working mode, controlling the multiplexing switching module to execute a switching action, selectively conducting the first driving loop or the second driving loop, and synchronously adjusting circuit parameters of the reconfigurable resonant network so as to enable the reconfigurable resonant network to work in the target working mode. And enabling the transmitting coil to work under the resonant frequency matched with the target working mode. According to the invention, an EPP low-frequency mode and an MPP high-frequency mode can be realized under a single-coil architecture, the problem that a single fixed parameter circuit cannot meet the resonance requirements of two protocols at the same time is solved, and the charging efficiency and stability of the system under different protocols are improved while the hardware cost is reduced.

Description

Technical Field

[0001] This application relates to the field of wireless charging technology, and in particular to an adaptive switching circuit and control method for wireless charging. Background Technology

[0002] With the widespread adoption of portable electronic devices, wireless charging technology has been widely used due to its convenience and versatility. In the field of wireless charging, the Qi standard developed by the Wireless Power Consortium (WPC) is currently the most widely used industry standard. With technological evolution, the Qi standard has progressed from early low-power versions to Qi 1.3, which supports higher power transmission, and further to Qi 2.0 based on magnetic alignment technology. The Qi 1.3 standard primarily includes the Extended Power Profile (EPP) protocol, with a typical operating frequency range between 110kHz and 205kHz (typically 128kHz). The Qi 2.0 standard introduces the Magnetic Power Profile (MPP) protocol, significantly increasing its operating frequency to approximately 360kHz to improve transmission efficiency and reduce the size of magnetic devices.

[0003] However, the significant difference in operating frequencies between the EPP and MPP protocols presents a serious challenge to the design of wireless charging transmitters, especially in single-coil transmitter schemes that prioritize miniaturization and low cost. First, wireless charging systems rely on an LC resonant network composed of a transmitting coil and a resonant capacitor for efficient energy transfer. According to the resonant frequency formula, with a fixed inductance value for the transmitting coil, operating frequencies of 128kHz and 360kHz correspond to drastically different resonant capacitance values. A fixed resonant network cannot simultaneously satisfy the optimal resonance conditions for both modes, leading to a sharp increase in reactive power loss when the system operates at mismatched frequencies, severely impacting charging efficiency and even preventing normal oscillation. Second, the requirements for power drive circuits and signal sampling circuits differ significantly between operating frequencies. In the low-frequency environment of EPP mode, the drive circuit focuses more on conduction losses, while in the high-frequency environment of MPP mode, switching losses become the primary concern, and high-frequency signals place higher demands on the bandwidth and response speed of the sampling circuit. Existing compatibility solutions typically employ a multi-coil stacked physical architecture, configuring independent coils and drive circuits for EPP and MPP respectively. This not only increases the size and thickness of the device but also significantly raises material costs. Another existing wideband design attempts to cover a wide frequency range with the same circuit, but often results in severe overheating in MPP high-frequency mode or insufficient control precision in EPP mode, making it difficult to balance the performance indicators of the two protocols.

[0004] Therefore, how to achieve efficient and stable compatibility between EPP and MPP modes under a single-coil architecture is a technical problem that urgently needs to be solved in the current wireless charging technology field. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an adaptive switching circuit and control method for wireless charging, which can solve the problem that a single fixed-parameter circuit in the prior art cannot simultaneously meet the resonance requirements of both EPP and MPP protocols.

[0006] In a first aspect, embodiments of this application provide an adaptive switching circuit for wireless charging.

[0007] An adaptive switching circuit for wireless charging according to an embodiment of this application includes: a transmitting coil; a first driving circuit for providing a power signal to the transmitting coil in a first operating mode; a second driving circuit for providing a power signal to the transmitting coil in a second operating mode, wherein the operating frequency of the second operating mode is higher than that of the first operating mode; a reconfigurable resonant network coupled between the first driving circuit, the second driving circuit, and the transmitting coil; a multiplexing switching module connected to the first driving circuit, the second driving circuit, and the reconfigurable resonant network; and a control unit connected to the first driving circuit, the second driving circuit, and the multiplexing switching module. The control unit is configured to parse the communication protocol of an external receiving device to determine a target operating mode, and control the multiplexing switching module to perform a switching action according to the target operating mode, selectively activating the control signal path of either the first driving circuit or the second driving circuit, and correspondingly adjusting the circuit parameters of the reconfigurable resonant network so that the transmitting coil operates at a resonant frequency matching the target operating mode.

[0008] The adaptive switching circuit for wireless charging according to the embodiments of this application has at least the following beneficial effects: by setting up a first driving loop and a second driving loop optimized for different frequencies in a single-coil architecture, and combining a reconfigurable resonant network and a multiplexing switching module, deep hardware compatibility with EPP low-frequency mode and MPP high-frequency mode is achieved. The adaptive switching circuit for wireless charging in this embodiment can intelligently identify the target operating mode according to the communication protocol of the receiving device, and use the control unit to drive the multiplexing switching module to reconstruct the circuit topology. It not only selectively conducts the driving loop control path adapted to the target mode, but also synchronously adjusts the circuit parameters of the resonant network to ensure that the transmitting coil can operate in the optimal resonant state at significantly different frequencies such as 128kHz or 360kHz. This design effectively solves the problem that a single fixed-parameter circuit in the prior art cannot simultaneously meet the resonant requirements of both EPP and MPP protocols. Without adding an additional transmitting coil, it avoids reactive power loss and heat generation caused by frequency mismatch, improves the power transmission efficiency and stability of the system in different modes, and reduces hardware costs and module size, thereby improving the integration and versatility of the product.

[0009] According to some embodiments of this application, the multiplexing switching module includes a drive path switching unit; both the first drive loop and the second drive loop are provided with drive signal input terminals; the input terminal of the drive path switching unit is connected to the drive signal output terminal of the control unit, and the output terminal of the drive path switching unit is connected to the drive signal input terminals of the first drive loop and the second drive loop respectively; the control unit is used to selectively project the drive signal to the drive signal input terminal of the first drive loop or the second drive loop through the drive path switching unit.

[0010] According to some embodiments of this application, the reconfigurable resonant network includes at least one capacitor branch, the capacitor branch including capacitors and switching devices connected in series; the multiplexing switching module includes a resonant network switching unit, the input terminal of the resonant network switching unit is connected to the resonant signal output terminal of the control unit, and the output terminals of the resonant network switching unit are connected one-to-one with the control terminals of the switching devices of the capacitor branches; the control unit is used to change the capacitor branches connected to the reconfigurable resonant network through the resonant network switching unit, thereby switching the resonant frequency of the transmitting coil.

[0011] According to some embodiments of this application, a sampling feedback module is further included, the sampling feedback module comprising: a first sampling circuit coupled to the first driving loop for acquiring power signals in the first operating mode; a second sampling circuit coupled to the second driving loop for acquiring power signals in the second operating mode; the multiplexing switching module further comprising a sampling path switching unit connected between the feedback signal input terminal of the control unit and the first sampling circuit and the second sampling circuit; the control unit is used to selectively receive power signals from the first sampling circuit or the second sampling circuit through the sampling path switching unit.

[0012] According to some embodiments of this application, the second operating mode is a magnetic power distribution mode, and the second sampling circuit includes a differential amplifier and a programmable gain amplifier; the first operating mode is an extended power distribution mode, and the first sampling circuit includes a current sensing resistor and an operational amplifier.

[0013] According to some embodiments of this application, the first drive circuit is a full-bridge inverter circuit for supporting the EPP charging protocol, and the second drive circuit is a high-frequency full-bridge inverter circuit for supporting the MPP charging protocol; the control unit is also connected to a voltage regulation module, the output terminal of which supplies power to the first drive circuit and the second drive circuit respectively, and the voltage regulation module is used to adjust the supply voltage according to the target operating mode.

[0014] Secondly, embodiments of this application provide an adaptive switching control method for wireless charging.

[0015] The adaptive switching control method for wireless charging according to embodiments of this application is applied to the adaptive switching circuit for wireless charging described in any embodiment of the first aspect. The adaptive switching control method for wireless charging includes: establishing communication with an external receiving device and parsing a configuration data packet of the receiving device; identifying the charging protocol supported by the receiving device based on the configuration data packet, and determining a target operating mode as a first operating mode or a second operating mode; if the current operating mode is inconsistent with the target operating mode, controlling the multiplexing switching module to perform a switching action according to the target operating mode, so as to selectively conduct the control signal path of the first driving circuit or the second driving circuit, and correspondingly adjusting the circuit parameters of the reconfigurable resonant network so that the transmitting coil operates at a resonant frequency matching the target operating mode.

[0016] The adaptive switching control method for wireless charging according to embodiments of this application has at least the following beneficial effects: By actively establishing communication and parsing the configuration data packets of the receiving device, it realizes the identification of the receiving protocol type (such as EPP or MPP) and intelligent decision-making on the target operating mode. When the current operating mode is detected to be inconsistent with the target operating mode, the method can automatically trigger the multiplexing switching module to perform hardware reconfiguration, select an appropriate control signal path to conduct and synchronously adjust the circuit parameters of the reconfigurable resonant network, thereby accurately locking the resonant frequency of the transmitting coil to a state matching the target protocol. This control logic not only realizes the seamless identification and automatic compatibility of the transmitting end with receiving devices of different protocols, allowing flexible switching between low-frequency and high-frequency modes without manual intervention from the user, but also ensures that the circuit always operates in the optimal physical state matching the capabilities of the receiving end, effectively avoiding problems such as low charging efficiency or oscillation failure caused by mode misjudgment or parameter mismatch, and improving the intelligence level, compatibility, and operational safety of the wireless charging system.

[0017] According to some embodiments of this application, when the current operating mode is inconsistent with the target operating mode, controlling the multiplexing switching module to perform a switching action according to the target operating mode includes: controlling the first driving circuit and the second driving circuit to stop outputting, so that the current on the transmitting coil is zero; adjusting the capacitance value of the reconfigurable resonant network to match the target operating mode; and controlling one of the first driving circuit and the second driving circuit that matches the target operating mode to receive a driving signal.

[0018] According to some embodiments of this application, the adaptive switching circuit for wireless charging further includes: a sampling feedback module, the sampling feedback module including a first sampling circuit and a second sampling circuit, the first sampling circuit being used to collect power signals in the first operating mode, and the second sampling circuit being used to collect power signals in the second operating mode; the step of controlling one of the first drive circuit and the second drive circuit that matches the target operating mode to receive a drive signal further includes: controlling one of the first sampling circuit and the second sampling circuit that matches the target operating mode to be connected to the feedback signal input terminal of the control unit.

[0019] According to some embodiments of this application, it further includes: if the control unit receives a mode switching request sent by the receiving device, it controls the first drive circuit and the second drive circuit to stop outputting, updates the target working mode according to the mode switching request, and performs the switching action again. Attached Figure Description

[0020] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the adaptive switching circuit for wireless charging in an embodiment. Figure 2 This is a schematic diagram of the main flow of the adaptive switching control method for wireless charging in an embodiment. Figure 3 This is a flowchart illustrating the process of controlling the multiplexing switching module to perform switching actions according to the target operating mode in an embodiment. Figure 4 This is a schematic diagram of the control flow of the control unit in the embodiment; Figure 5 The signal control timing diagram of the control unit in this embodiment is shown. Detailed Implementation

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0022] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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.

[0023] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0025] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] It should be noted that in all specific embodiments of this application, when processing data related to user identity or characteristics, such as user information, user behavior data, user historical data, and user location information, user permission or consent is obtained first. Furthermore, the collection, use, and processing of this data comply with relevant laws, regulations, and standards. In addition, when embodiments of this application require access to sensitive personal information of users, separate permission or consent from the user is obtained through pop-ups or redirection to confirmation pages. Only after obtaining the user's separate permission or consent is the necessary user-related data required for the proper functioning of these embodiments acquired.

[0027] Firstly, embodiments of this application provide an adaptive switching circuit for wireless charging. The adaptive switching circuit for wireless charging in this embodiment aims to be compatible with two wireless charging standards with different operating frequencies and power characteristics within a single transmitting system. For example, the first operating mode can be an EPP (Extended Power Profile) mode conforming to the Qi 1.3 standard, with a typical operating frequency between 110kHz and 148kHz; the second operating mode can be an MPP (Magnetic Power Profile) mode conforming to the Qi 2.0 standard, with a typical operating frequency of approximately 360kHz. However, those skilled in the art should understand that the specific definitions of the first and second operating modes are not limited to these, and they are applicable to any wireless charging application scenario involving high-frequency switching.

[0028] The adaptive switching circuit for wireless charging in this embodiment includes: a transmitting coil (Tx Coil), a first driving circuit, a second driving circuit, a reconfigurable resonant network, a multiplexing switching module, and a control unit (MCU).

[0029] Understandably, to adapt to different operating modes, the adaptive switching circuit for wireless charging in this embodiment sets up two independent power generation paths. The first drive circuit is configured to operate in a first operating mode (e.g., low-frequency EPP mode), and its output is capable of generating an AC power signal that meets the frequency and power requirements of that mode. The second drive circuit is configured to operate in a second operating mode (e.g., high-frequency MPP mode). Since the operating frequency of the second operating mode is significantly higher than that of the first operating mode (e.g., reaching 360kHz), the second drive circuit typically employs power devices or topologies more suitable for high-frequency switching to reduce switching losses. Both drive circuits operate under the control unit's scheduling, but typically only one drive circuit is actively operating at any given time to provide energy to the transmitting coil.

[0030] The transmitting coil is the final element for power transmission. To achieve efficient wireless power transmission, the transmitting coil needs to form an LC resonant circuit with a capacitor in the circuit, and the resonant frequency of this circuit should match the operating frequency of the current drive circuit. A reconfigurable resonant network is coupled between the two drive circuits and the transmitting coil. Unlike resonant networks with fixed parameters, the reconfigurable resonant network in this embodiment has adjustable circuit parameters (primarily equivalent capacitance values). For example, by changing the capacitor combination in the connected circuit, the reconfigurable resonant network can switch between at least two different resonant frequencies, thereby adapting to the low-frequency requirements of the first operating mode and the high-frequency requirements of the second operating mode, respectively.

[0031] The multiplexing switching module is a key component connecting the drive circuit, resonant network, and control unit. In terms of circuit topology, it establishes connections with the first drive circuit, the second drive circuit, and the reconfigurable resonant network. Functionally, the multiplexing switching module acts as a "signal router" and a "parameter configurator." It receives switching commands from the control unit and performs the following actions: Path selection: On the drive signal transmission path, it can selectively connect the first drive circuit or the second drive circuit to the transmitting coil, while cutting off the interference of the other circuit.

[0032] Parameter reconfiguration: In conjunction with the selection of the path, it synchronously adjusts the internal connection state of the reconfigurable resonant network (e.g., connecting or disconnecting specific capacitor branches), thereby changing the physical characteristics of the entire transmission circuit.

[0033] The control unit (e.g., a microcontroller (MCU)) is the core of the entire system. It maintains electrical connections with the first drive circuit, the second drive circuit, and the multiplexing switching module. During operation, the control unit is first responsible for communicating with the external receiving device placed on the transmitting coil. By parsing the digital communication protocol (such as configuration data packets) fed back by the receiving end, the control unit can identify whether the device supports a first operating mode (such as a regular mobile phone) or a second operating mode (such as a new type of magnetic device), thereby determining the target operating mode. Once the target operating mode is determined, the control unit sends a control signal to the multiplexing switching module according to the mode to execute the switching action: if the target is the first operating mode, the control unit controls the multiplexing switching module to conduct the path of the first drive circuit and adjusts the reconfigurable resonant network to the corresponding low-frequency resonant state; if the target is the second operating mode, the control unit controls the multiplexing switching module to conduct the path of the second drive circuit and adjusts the reconfigurable resonant network to the corresponding high-frequency resonant state.

[0034] Through the above architecture, the adaptive switching circuit for wireless charging in this embodiment can automatically and seamlessly switch between two different sets of driving and resonant parameters according to the type of load device without manual intervention, achieving compatibility of a single hardware platform with multiple protocols and frequencies.

[0035] Understandably, in order to achieve precise control of different drive loops and avoid signal interference, the drive signal allocation mechanism of the multiplexing switching module is designed more specifically in some embodiments. In some embodiments, such as Figure 1 As shown, the multiplexing switching module includes a drive path switching unit (Switch A). This unit is mainly responsible for processing the PWM (Pulse Width Modulation) drive signal from the control unit and guiding it to the correct power stage circuit. For example, the connection relationship of the drive path switching unit is as follows: First drive loop (e.g., Figure 1 (Q1E, Q2E, Q3E, and Q4E in the second drive circuit) and the second drive circuit (such as Q1E, Q2E, Q3E, and Q4E in the second drive circuit) Figure 1Each of the four transistors (Q1, Q2, Q3, and Q4) in the full-bridge or half-bridge circuit has a drive signal input terminal. These input terminals are typically connected to the gate driver of the power switching transistor (such as MOSFET) in their respective full-bridge or half-bridge circuits. The drive path switching unit (Switch A) has input and output terminals. For example, its input terminal is connected to the drive signal output terminal (e.g., the PWM_OUT pin) of the control unit (MCU), and its output terminal is divided into two paths, connected to the drive signal input terminals of the first drive loop and the second drive loop, respectively. In actual operation, the control unit usually outputs drive signals through only one or a limited number of PWM pins. The drive path switching unit (Switch A) acts as a "signal router" or "logic switch".

[0036] When the control unit determines that the target operating mode is the first operating mode (e.g., EPP mode), it sends a first control command to the drive path switching unit (e.g., pulling the GPIO_A pin high). In response to this command, the drive path switching unit projects the PWM drive signal received at its input to the drive signal input of the first drive loop, while simultaneously cutting off the signal path to the second drive loop. At this time, only the power switch in the first drive loop receives the switching signal and starts operating. Conversely, when the control unit determines that the target operating mode is the second operating mode (e.g., MPP mode), it sends a second control command to the drive path switching unit (e.g., pulling the GPIO_A pin low). The drive path switching unit then switches the transmission path of the PWM drive signal to the drive signal input of the second drive loop, while simultaneously blocking the signal to the first drive loop.

[0037] In this way, the control unit does not need to configure two completely independent PWM generators for the two drive loops, saving MCU I / O resources. Simultaneously, the drive path switching unit implements interlocking between the two drive loops at the hardware physical level, effectively preventing circuit failures that may be caused by simultaneous operation of the two drive loops due to software errors. In specific hardware implementations, the drive path switching unit can be composed of analog switching chips, multiplexers, or discrete MOSFET logic circuits.

[0038] As is well known, the resonant frequency f of the wireless charging transmitter is determined by the inductance L of the transmitting coil and the total capacitance C of the resonant circuit, satisfying the formula. Since the inductance L of the transmitting coil in this embodiment is relatively constant, and the frequencies of the first operating mode (e.g., EPP, approximately 128kHz) and the second operating mode (e.g., MPP, approximately 360kHz) differ significantly, the capacitance C must be substantially adjusted to achieve matching.

[0039] Understandably, in order to ensure that the transmitting coil achieves optimal energy transmission efficiency at different operating frequencies, in some embodiments, such as Figure 1 As shown, the reconfigurable resonant network includes at least one capacitor branch (such as...). Figure 1 The capacitor branch (S1 and Ctx4) includes capacitors and switching devices connected in series; the multiplexing switching module includes a resonant network switching unit (Switch B), the input of which is connected to the resonant signal output of the control unit, and the output of which is connected one-to-one with the control terminal of the switching device in the capacitor branch.

[0040] For example, the reconfigurable resonant network in the embodiment includes at least one capacitor branch. The capacitor branch is not a simple fixed connection, but a controlled branch formed by connecting capacitive elements and switching devices (such as MOSFETs or relays) in series. In specific circuit implementations, the reconfigurable resonant network can take various forms, such as: Incremental architecture: A base capacitor is provided, and the capacitor branch is connected in parallel with the base capacitor. When the switching device is turned on, the capacitor branch is connected to the circuit, the total capacitance increases, and the resonant frequency decreases (corresponding to EPP mode); when the switching device is turned off, only the base capacitor remains, the total capacitance decreases, and the resonant frequency increases (corresponding to MPP mode).

[0041] Switching architecture: Multiple independent capacitor branches are set up, each corresponding to a different mode, and one can be connected by a switching device.

[0042] To control the switching on and off of the aforementioned capacitor branch, the multiplexing switching module in this embodiment also includes a resonant network switching unit (Switch B). The input of Switch B is connected to the resonant signal output of the control unit (MCU). This is typically a general-purpose input / output interface of the MCU (such as...). Figure 1 GPIO B in the circuit is used to output high and low level control signals. The output of Switch B is connected one-to-one with the control terminal of the switching device (such as the gate of a MOSFET) in the capacitor branch. Switch B here plays the role of level conversion or drive enhancement, ensuring reliable driving of the switching device.

[0043] The control unit dynamically switches the resonant frequency of the transmitting coil by changing the combination of capacitor branches connected to the reconfigurable resonant network through the resonant network switching unit (Switch B). For example: Entering EPP mode (low frequency): When the control unit determines that EPP charging needs to be performed, it outputs a control signal through Switch B to turn on the switching devices in a specific capacitor branch. This allows a larger capacitance value to be connected to the LC circuit, adjusting the system's resonant frequency to around 128kHz to match the low-frequency drive signal of the first drive circuit.

[0044] Entering MPP mode (high frequency): When the control unit switches to MPP charging, it outputs a reverse control signal through Switch B to disconnect the aforementioned capacitor branch (or switch to another set of small capacitor branches). This significantly reduces the total capacitance of the LC circuit, thereby raising the resonant frequency to around 360kHz to match the high-frequency drive signal of the second drive circuit.

[0045] Understandably, in wireless charging systems, real-time acquisition of voltage and current signals on the transmitting coil is necessary to achieve precise power regulation (PID control) and foreign object detection (FOD). Considering the significant differences in operating frequency, signal amplitude, and waveform characteristics between the first operating mode (e.g., EPP mode) and the second operating mode (e.g., MPP mode) in the adaptive switching circuit used for wireless charging in the embodiments, a single sampling circuit cannot simultaneously meet the high-precision sampling requirements of both modes. Therefore, in some embodiments, a sampling feedback module incorporating dual-channel sampling and switching functions is designed.

[0046] For example, in some embodiments, such as Figure 1 As shown, the sampling feedback module specifically includes two sets of specially designed sampling circuits: First sampling circuit (e.g., adapted for EPP mode): This circuit is coupled to the first drive loop and is used to acquire power signals at low frequencies (approximately 128kHz). For example, the first sampling circuit uses a current-sensing resistor in conjunction with an operational amplifier (Op-Amp). In EPP mode, the drive current is large and the frequency is low. The current-sensing resistor is connected in series in the loop (e.g., on the low side of a full-bridge circuit). By measuring the voltage drop across the resistor and amplifying it with the op-amp, an accurate current signal can be obtained. This approach is simple in structure, low in cost, and sufficient to handle signal bandwidths in the hundreds of kHz range.

[0047] The second sampling circuit (e.g., adapted for MPP mode): This circuit is coupled to the second drive loop and is used to acquire power signals at high frequencies (approximately 360kHz). The second sampling circuit employs a differential amplifier combined with a programmable gain amplifier (PGA). Due to the extremely high frequency of MPP mode, conventional current sensing resistor schemes may introduce significant parasitic inductance effects, and high-frequency signals are highly susceptible to common-mode interference. Therefore, using a high-bandwidth, high common-mode rejection ratio (CMRR) differential amplifier for signal extraction, and dynamically adjusting the gain through the PGA, ensures that a high signal-to-noise ratio sampling signal is obtained even in high-frequency environments, meeting the control accuracy requirements of the Qi 2.0 standard.

[0048] To send the two different analog signals (the power signals acquired by the first and second sampling circuits) to the same ADC (analog-to-digital converter) interface or signal processing unit of the control unit, in some embodiments, the multiplexing switching module further includes a sampling path switching unit (Switch C). The input side of the sampling path switching unit is connected to the outputs of the first and second sampling circuits, respectively; its output side is connected to the feedback signal input of the control unit (e.g., the ADC_IN pin). The control unit controls the state of the sampling path switching unit (Switch C) via GPIO. When the system is operating in the first working mode (e.g., EPP mode), the control unit instructs the sampling path switching unit (Switch C) to turn on the channel of the first sampling circuit. At this time, the MCU's ADC reads the low-frequency current signal processed by the operational amplifier, and performs power closed-loop control under the EPP protocol accordingly. When the system switches to the second operating mode (e.g., MPP mode), the control unit instructs the sampling path switching unit (Switch C) to switch channels and turn on the second sampling circuit. At this time, the MCU's ADC reads the high-frequency current signal after differential amplification and PGA conditioning, and executes fast response control under the MPP protocol accordingly.

[0049] With this "dual-channel sampling + back-end switching" architecture, the adaptive switching circuit for wireless charging in this embodiment not only solves the compatibility problem of high and low frequency signals, but also eliminates the need for the MCU to configure multiple high-precision ADC channels. It only needs to reuse one set of ADC resources to complete high-precision sampling in both modes, further optimizing the system resource configuration.

[0050] Understandably, in some embodiments, the first drive loop may employ a full-bridge inverter circuit suitable for low-frequency, high-power transmission. This circuit consists of four power MOSFETs (e.g., Figure 1 The circuit consists of four power MOSFETs (Q1E, Q2E, Q3E, Q4E) forming an H-bridge structure, which converts DC voltage into an AC square wave of approximately 128kHz under the drive of the control unit. The second drive circuit can employ a high-frequency full-bridge inverter circuit suitable for high-frequency operation. This circuit also consists of four power MOSFETs (e.g., Q1E, Q2E, Q3E, Q4E). Figure 1 The circuit consists of Q1, Q2, Q3, and Q4. Compared to the first drive circuit, these MOSFETs are typically selected with lower gate charge and shorter reverse recovery time to reduce losses and heat generation during 360kHz high-frequency switching.

[0051] In some embodiments, the adaptive switching circuit for wireless charging further includes a voltage regulation module (such as...). Figure 1The OVP, Buck, and Boost modules in the power management system can be connected to a USB Type-C interface or other DC power sources. Under the control unit's regulation, the voltage regulation module outputs a variable DC voltage (e.g., adjustable from 5V to 25V), which is then supplied to the power inputs of both the first and second drive circuits. During operation, the control unit dynamically adjusts the output voltage of the voltage regulation module based on the target operating mode and feedback from the receiver. In EPP mode, the voltage regulation module adjusts the voltage according to the power requirements of the Qi protocol, and the full-bridge circuit inverts it into low-frequency AC power. In MPP mode, the voltage regulation module similarly adjusts the voltage according to the MPP protocol, and the high-frequency full-bridge circuit inverts it into high-frequency AC power. This "shared pre-stage voltage regulator + independent post-stage inverter" architecture further simplifies the complexity of the power management system.

[0052] Secondly, embodiments of this application provide an adaptive switching control method for wireless charging. The adaptive switching control method for wireless charging in this embodiment is implemented based on the adaptive switching circuit for wireless charging described in the first aspect embodiment.

[0053] like Figure 2 and Figure 4 As shown, the adaptive switching control method for wireless charging in the embodiment includes, but is not limited to, steps S100 to S200: S100: Establish communication with the external receiving device and parse the configuration data packet of the receiving device; S200: Based on the configuration data packet, identify the charging protocol supported by the receiving device and determine the target working mode as the first working mode or the second working mode. S300. When the current working mode is inconsistent with the target working mode, the multiplexing switching module is controlled to perform a switching action according to the target working mode, so as to selectively conduct the control signal path of the first driving circuit or the second driving circuit, and adjust the circuit parameters of the reconfigurable resonant network accordingly, so that the transmitting coil operates at the resonant frequency that matches the target working mode.

[0054] In step S100, after the system powers on and completes initialization (including MCU and Qi protocol stack initialization), the transmitter enters Ping state. This typically includes an analog ping to detect if an object is placed on the transmitting coil, and a subsequent digital ping to wake up the receiver. Once the receiver is detected, the MCU receives the signal from the receiver via the ASK demodulation circuit. The receiver sends a series of data packets according to wireless charging standards (such as the WPC Qi standard), including a configuration packet. This configuration packet contains key information such as the receiver's identification information, supported power levels, and supported protocol versions.

[0055] In step S200, the control unit (MCU) decodes and performs logical judgments on the received configuration information. For example, the first operating mode corresponds to the Extended Power Distribution (EPP) mode or the Baseline Power Distribution (BPP) mode in the Qi standard, with a typical operating frequency range of low (e.g., 110kHz-205kHz, typical value 128kHz); the second operating mode corresponds to the Magnetic Power Distribution (MPP) mode in the Qi 2.0 standard, with a higher operating frequency (e.g., 360kHz). For example, the judgment logic is as follows: The MCU first determines whether the receiver supports the MPP protocol (Qi 2.0). If it does, the target operating mode is locked to MPP mode (second operating mode). If the receiver does not support MPP, it further determines whether it supports EPP; if it supports EPP or only supports BPP, the target operating mode is locked to EPP mode (first operating mode). This judgment mechanism ensures that the transmitter always operates using the highest or most optimized protocol supported by the receiver.

[0056] In step S300, after determining the target operating mode, the MCU checks the current hardware configuration state (i.e., the current operating mode). If the current circuit state does not match the target mode (for example, the circuit is in standby or the default EPP state, while an MPP device is detected), a switching process is triggered. The MCU sends control commands to the multiplexing switching module to perform the following hardware reconfiguration actions: Control signal path switching: Selectively activates the control signal path of either the first or second drive circuit. For example, if the target is MPP mode, the multiplexing switching module will cut off the PWM signal to the low-frequency full-bridge circuit and project the high-frequency PWM signal generated by the MCU to the high-frequency full-bridge drive circuit, thereby enabling the high-performance MOSFET drive path suitable for 360kHz operation.

[0057] Resonance parameter adjustment: Correspondingly adjust the circuit parameters of the reconfigurable resonant network. Since the operating frequencies of the first and second operating modes differ significantly (e.g., 128kHz vs. 360kHz), the capacitance values ​​in the LC network must be changed to match the target resonant frequency. The MCU controls the multiplexing switching module to change the resonant capacitor combination in the input circuit, shifting the inherent resonant frequency of the transmitting coil circuit to a frequency band that matches the target operating mode.

[0058] To ensure the safety and stability of the circuit during mode switching and to avoid component damage caused by directly switching the circuit topology under high voltage and high current conditions, some embodiments implement specific timing control for the switching action in step S300. In some embodiments, such as Figure 3 As shown, step S300 further includes, but is not limited to, steps S310 to S330: S310: Control the first and second drive circuits to stop outputting, so that the current on the transmitting coil returns to zero. S320. Adjust the capacitance value of the reconfigurable resonant network to match the target operating mode; S330 controls one of the first and second drive circuits to receive a drive signal that matches the target operating mode.

[0059] In step S310, when the MCU decides to perform a mode switch, it first enters the "drive shutdown" stage. The MCU immediately stops sending PWM drive signals to the current drive loop (whether it's the first drive loop or the second drive loop). For example, it sets the gate drive signals of all full-bridge MOSFETs to an invalid level (e.g., low level), causing all power MOSFETs to turn off. The purpose of this step is to cut off the power supply and reserve a buffer time (e.g., ...). Figure 5 (As shown by the black bar corresponding to "Drive Off"). During this buffer period, the remaining energy in the transmitting coil and resonant network is dissipated through the loop until the current in the coil decays to a safe level of zero or close to zero. This process ensures that subsequent circuit reconfiguration is performed under "no voltage" or "no current" conditions.

[0060] In step S320, after confirming that the drive circuit has stopped outputting and a preset dead time has elapsed, the MCU controls the resonant network switching unit (Switch B) in the multiplexing switching module to operate. For example... Figure 5As shown, during the "LC switching" period, the MCU changes the level of the GPIO control signal to turn on or off specific switching devices (such as S1, S2, or S3) in the reconfigurable resonant network. If the target is MPP mode (360kHz), the MCU controls the switch to remove some of the larger parallel capacitors or add smaller capacitor combinations, reducing the total capacitance of the LC network so that it forms a high-frequency resonant circuit with the transmitting coil. If the target is EPP mode (128kHz), the MCU controls the switch to add a larger capacitor combination, increasing the total capacitance of the LC network so that it forms a low-frequency resonant circuit with the transmitting coil. Since the circuit is in a power-off state at this time, the above switching action is a "cold switching," which avoids the switching devices being subjected to high power stress at the moment of action, thus extending the device life.

[0061] In step S330, after the physical reconstruction of the circuit parameters is completed, proceed to... Figure 5 The "power recovery" stage is shown. The MCU selects the corresponding drive signal path based on the target operating mode. If switching to MPP mode, the MCU projects a high-frequency PWM signal to the second drive circuit (high-frequency full bridge) through the drive path switching unit (Switch A), driving Q1-Q4 to operate; if switching to EPP mode, the MCU projects a low-frequency PWM signal to the first drive circuit, driving Q1E-Q4E to operate. Preferably, when restoring power output, the MCU adopts a soft-start strategy, that is, gradually increasing the duty cycle of the PWM signal to smoothly increase the voltage and current on the transmitting coil until the target operating point is reached, thereby completing the entire adaptive switching process.

[0062] Understandably, to achieve closed-loop power control (PID control) and foreign object detection (FOD) functions, the MCU needs to acquire current and voltage information on the transmitting coil in real time. Due to the significant differences in operating frequency and signal characteristics between the first operating mode (EPP) and the second operating mode (MPP), some embodiments of the adaptive switching circuit for wireless charging in the first aspect embodiment provide independent sampling channels for the two operating modes. Correspondingly, in some embodiments, before step S330 controls the drive circuit to receive the drive signal (i.e., restore power output), step S340 is also included: S340, one of the first and second sampling circuits that matches the target operating mode is connected to the feedback signal input terminal of the control unit.

[0063] In step S340, the MCU controls the sampling path switching unit (SwitchC) in the multiplexing switching module to select the route for the feedback signal. The timing of this step is also as follows... Figure 5As shown, this process is executed during the "sampling path switching" period, typically in parallel with the LC network switching in step S320, and must be completed before the drive signal recovers. When the target operating mode is the first operating mode (e.g., EPP mode), the first sampling circuit is activated. EPP mode operates at a lower frequency (approximately 128kHz) and primarily focuses on the effective value of the current. The first sampling circuit typically uses a current-sensing resistor connected in series in a full-bridge circuit, working with an operational amplifier to convert the current signal into a voltage signal. The MCU controls Switch C to connect the output of the first sampling circuit to the MCU's ADC input pin (or demodulation input pin), while simultaneously disconnecting the second sampling circuit. At this point, the MCU is ready to receive feedback data that conforms to the characteristics of the EPP signal. When the target operating mode is the second operating mode (e.g., MPP mode), the second sampling circuit is activated. MPP mode operates at a higher frequency (approximately 360kHz) and requires higher accuracy in the phase and amplitude of the signal (used for high-precision Q-value detection and ASK communication demodulation). The second sampling circuit typically uses a differential amplifier (DiffAmp) in conjunction with a programmable gain amplifier (PGA). Differential amplifiers effectively suppress high-frequency common-mode interference, while PGAs provide flexible signal amplification. The MCU controls Switch C to switch channels, connecting the output of the second sampling circuit to the MCU's ADC input pin.

[0064] By switching the sampling path before power recovery, problems such as signal distortion, ADC overflow, or feedback control loop divergence caused by sampling circuit mismatch (e.g., using a low-frequency op-amp to sample a high-frequency signal) during mode switching are avoided. This ensures that the MCU can obtain accurate voltage and current data the moment the power signal reappears in step S330, thereby immediately entering a stable closed-loop control state.

[0065] Understandably, during wireless charging, the communication link remains active, and the MCU continuously monitors feedback data packets from the receiving device (RX). The receiving device may send specific instructions to the transmitting end to request a change in operating mode, depending on the current battery state, thermal management strategy, or the progress of the handshake phase. Therefore, in some embodiments, the adaptive switching control method for wireless charging further includes step S400: S400. If the control unit receives a mode switching request sent by the receiving device, it controls the first drive circuit and the second drive circuit to stop outputting, updates the target working mode according to the mode switching request, and performs the switching action again.

[0066] For example, in step S400, in some cases (e.g., devices based on the Qi 2.0 standard), to quickly establish a connection, the system may initially start charging in a more compatible first operating mode (such as BPP or EPP). In this mode, the transmitting coil operates at a lower resonant frequency (e.g., 128kHz) and is powered by the first drive circuit. As charging progresses, when the receiving device confirms successful authentication or detects that the coil coupling condition meets the requirements for higher power transmission, the receiving end will send a "mode switching request" (or dynamic upgrade request). When the MCU parses this request, it executes the following logic: Interrupt current transmission: Immediately respond to the request, forcibly stopping the PWM output of the currently operating first drive circuit and reducing the transmitter coil current to zero. This is to prevent high-voltage spikes from being generated when switching circuit parameters under load.

[0067] Update Status: The MCU updates the "Target Operating Mode" in its internal system status variables from the first operating mode to the second operating mode (MPP mode). The logic of steps S300 and S310-S340 in the aforementioned embodiments is called again. Based on the new target mode (MPP), the MCU controls the multiplexing switching module to operate.

[0068] Reboot Power: After the hardware reconstruction is completed, the system will perform a soft reboot in MPP mode and enter the high-power charging stage.

[0069] This mechanism ensures that the wireless charging system has the ability to "hot-upgrade" or "dynamically adjust," allowing for a smooth transition between different protocols and optimizing the charging experience without requiring the user to manually remove the device and power it off.

[0070] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. An adaptive switching circuit for wireless charging, characterized in that, include: Transmitting coil; A first drive circuit is used to provide a power signal to the transmitting coil in a first operating mode; The second driving circuit is used to provide a power signal to the transmitting coil in the second operating mode, wherein the operating frequency of the second operating mode is higher than that of the first operating mode. A reconfigurable resonant network is coupled between the first driving circuit, the second driving circuit, and the transmitting coil; The multiplexing switching module is connected to the first driving circuit, the second driving circuit, and the reconfigurable resonant network, respectively. The control unit is connected to the first drive circuit, the second drive circuit, and the multiplexing switching module; The control unit is used to parse the communication protocol of the external receiving device to determine the target operating mode, and control the multiplexing switching module to perform a switching action according to the target operating mode, so as to selectively conduct the control signal path of the first driving circuit or the second driving circuit, and correspondingly adjust the circuit parameters of the reconfigurable resonant network so that the transmitting coil operates at a resonant frequency that matches the target operating mode.

2. The adaptive switching circuit for wireless charging according to claim 1, characterized in that, The multiplexing switching module includes a drive path switching unit; both the first drive circuit and the second drive circuit are provided with drive signal input terminals. The input terminal of the drive path switching unit is connected to the drive signal output terminal of the control unit, and the output terminal of the drive path switching unit is connected to the drive signal input terminals of the first drive circuit and the second drive circuit respectively. The control unit is used to selectively project the drive signal to the drive signal input terminal of the first drive circuit or the second drive circuit through the drive path switching unit.

3. The adaptive switching circuit for wireless charging according to claim 1, characterized in that, The reconfigurable resonant network includes at least one capacitor branch, which includes capacitors and switching devices connected in series. The multiplexing switching module includes a resonant network switching unit. The input terminal of the resonant network switching unit is connected to the resonant signal output terminal of the control unit, and the output terminals of the resonant network switching unit are connected one-to-one with the control terminals of the switching devices in the capacitor branch. The control unit is used to change the capacitor branch connected to the reconfigurable resonant network through the resonant network switching unit, thereby switching the resonant frequency of the transmitting coil.

4. The adaptive switching circuit for wireless charging according to claim 1, characterized in that, It also includes a sampling feedback module, which includes: The first sampling circuit, coupled to the first driving loop, is used to acquire the power signal in the first working mode; The second sampling circuit, coupled to the second driving loop, is used to acquire the power signal in the second operating mode; The multiplexing switching module further includes a sampling path switching unit, which is connected between the feedback signal input terminal of the control unit and the first sampling circuit and the second sampling circuit. The control unit is used to selectively receive power signals from either the first sampling circuit or the second sampling circuit via the sampling path switching unit.

5. The adaptive switching circuit for wireless charging according to claim 4, characterized in that, The second operating mode is a magnetic power distribution mode, and the second sampling circuit includes a differential amplifier and a programmable gain amplifier; the first operating mode is an extended power distribution mode, and the first sampling circuit includes a current sensing resistor and an operational amplifier.

6. The adaptive switching circuit for wireless charging according to claim 1, characterized in that, The first drive circuit is a full-bridge inverter circuit for supporting the EPP charging protocol, and the second drive circuit is a high-frequency full-bridge inverter circuit for supporting the MPP charging protocol. The control unit is also connected to a voltage regulation module. The output of the voltage regulation module supplies power to the first drive circuit and the second drive circuit respectively. The voltage regulation module is used to adjust the power supply voltage according to the target working mode.

7. An adaptive switching control method for wireless charging, characterized in that, An adaptive switching circuit for wireless charging as described in any one of claims 1-6, comprising: Establish communication with an external receiving device and parse the configuration data packets of the receiving device; Based on the configuration data packet, identify the charging protocol supported by the receiving device and determine the target working mode as either the first working mode or the second working mode. When the current operating mode is inconsistent with the target operating mode, the multiplexing switching module is controlled to perform a switching action according to the target operating mode, so as to selectively conduct the control signal path of the first driving circuit or the second driving circuit, and correspondingly adjust the circuit parameters of the reconfigurable resonant network so that the transmitting coil operates at a resonant frequency that matches the target operating mode.

8. The adaptive switching control method for wireless charging according to claim 7, characterized in that, When the current operating mode is inconsistent with the target operating mode, controlling the multiplexing switching module to perform a switching action according to the target operating mode includes: Control the first drive circuit and the second drive circuit to stop outputting, so that the current on the transmitting coil returns to zero; Adjust the capacitance value of the reconfigurable resonant network to match the target operating mode; Control one of the first drive circuits and the second drive circuit that matches the target operating mode to receive a drive signal.

9. The adaptive switching control method for wireless charging according to claim 8, characterized in that, The adaptive switching circuit for wireless charging further includes a sampling feedback module, which includes a first sampling circuit and a second sampling circuit. The first sampling circuit is used to collect the power signal in the first working mode, and the second sampling circuit is used to collect the power signal in the second working mode. The method of controlling one of the first and second drive circuits that matches the target operating mode to receive a drive signal further includes: The control circuit connects one of the first sampling circuit and the second sampling circuit that matches the target operating mode to the feedback signal input terminal of the control unit.

10. The adaptive switching control method for wireless charging according to claim 7, characterized in that, Also includes: If the control unit receives a mode switching request sent by the receiving device, it controls the first drive circuit and the second drive circuit to stop outputting, updates the target working mode according to the mode switching request, and performs the switching action again.

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