Wireless charging circuit and electronic device

Abstract

The utility model belongs to wireless charging technical field, concretely relates to a wireless charging circuit and electronic equipment, aims at solving in prior art, has not appeared the scheme of the dynamic adjustment of effective inductance through the coil segmentation winding and the combination switching switch, provides wireless charging circuit includes: full bridge drive circuit, first drive node and second drive node are at least included in full bridge drive circuit, LC resonant circuit is connected between first drive node and second drive node, LC resonant circuit includes transmitting end coil, and transmitting end coil includes first coil segment and second coil segment, coil switching switch, one end of coil switching switch connects the terminal between first coil segment and second coil segment, and the other end connects first drive node. Through the combination of coil segmentation structure and full bridge drive circuit, support wide frequency range work, adapt the resonant frequency of different equipment, expand the application scene of wireless charging system.

Description

Technical Field

[0001] This utility model belongs to the field of wireless charging technology, specifically relating to a wireless charging circuit and electronic device. Background Technology

[0002] In the field of wireless charging technology, the diversification of smart devices (such as smartphones, smartwatches, and wireless earphones) has placed higher demands on the compatibility of the transmitting coil. Traditional wireless charging solutions suffer from the following technical bottlenecks: 1. Poor compatibility with multiple devices: In existing technologies, separate coils, drive circuits, and demodulation circuits are typically used to meet the charging needs of different devices (such as mobile phones and watches). For example, mobile phone charging requires a larger coil to meet power transmission requirements, while watch charging requires a smaller coil due to size limitations. The differences in the number of turns, inductance, and resonant frequency between the two coils are significant, making it impossible for traditional solutions to achieve multi-device compatibility with a single coil. Multiple independent circuits must be relied upon, resulting in high costs and complex structures.

[0003] 2. Low frequency adaptation efficiency: Different devices operate at different frequencies (e.g., mobile phones may operate at lower frequencies, while fast charging for watches may require higher frequencies). The fixed inductance of a traditional single coil results in significant differences in AC impedance at different frequencies. As the frequency increases, the coil impedance increases, and the energy transfer efficiency decreases significantly, failing to meet the high-efficiency charging needs of all scenarios.

[0004] 3. Structural design limitations: Existing coils are typically single, continuously wound structures, lacking a flexible mechanism for adjusting inductance. Although some solutions attempt to adjust resonant parameters by switching external capacitors, the coil's inductance itself is fixed, failing to fundamentally solve the impedance matching problem at different frequencies, and its adaptability remains limited by the inherent parameters of the coil.

[0005] Therefore, there is an urgent need for a circuit to solve at least one of the above problems. Utility Model Content

[0006] This application provides a wireless charging circuit and electronic device, aiming to solve the problem of the lack of a solution that dynamically adjusts the effective inductance by segmenting the coil winding and combining it with a switching switch. Traditional solutions either rely on multiple coils working independently or use fixed-structure coils with limited capacitor tuning, neither of which addresses the issue of combining the design of the coil's own structure (such as segmented intermediate taps) with the switching control.

[0007] In a first aspect, this application provides a wireless charging circuit, comprising: A full-bridge drive circuit, wherein the full-bridge drive circuit includes at least a first drive node and a second drive node; An LC resonant circuit is connected between the first driving node and the second driving node. The LC resonant circuit includes a transmitting coil, which includes a first coil segment and a second coil segment. A coil switching switch, one end of which is connected to the terminal between the first coil segment and the second coil segment, and the other end of which is connected to the first drive node.

[0008] In some embodiments, the transmitting coil is wound with a center tap to form the first coil segment and the second coil segment, and the coil switching switch is connected to the terminal corresponding to the center tap.

[0009] In some embodiments, the LC resonant circuit further includes a resonant capacitor connected between the second coil segment and the second driving node.

[0010] In some embodiments, the LC resonant circuit includes a plurality of resonant capacitors connected in parallel and a plurality of resonant switches, wherein the resonant capacitors are connected in series with the resonant switches.

[0011] In some embodiments, the full-bridge drive circuit includes at least a first switch group and a second switch group, wherein the first switch group forms the first drive node and the second switch group forms the second drive node.

[0012] In some embodiments, the first switch group includes at least two switching transistors, and the first drive node is disposed between the two switching transistors.

[0013] In some embodiments, the second switch group includes at least two switching transistors, and the second drive node is disposed between the two switching transistors.

[0014] In some embodiments, the capacitance value of each of the resonant capacitors is different, and the number of the resonant switches is less than or equal to the number of the resonant capacitors.

[0015] In some embodiments, the first switch group and the second switch group are respectively connected between a preset power supply and a preset ground terminal. The full-bridge drive circuit includes a first drive mode and a second drive mode. In the first drive mode, the preset power supply is connected to the first drive node and the second drive node is connected to the preset ground terminal. In the second drive mode, the preset power supply is connected to the second drive node and the first drive node is connected to the preset ground terminal.

[0016] In a second aspect, this application provides an electronic device, which includes a wireless charging circuit as provided in any of the first aspects above.

[0017] This application provides a wireless charging circuit that dynamically adjusts the effective inductance via a coil switching switch. A single coil can be compatible with the charging needs of different devices such as mobile phones and watches, eliminating the need for independent coils and drive circuits, thus reducing hardware costs and structural complexity. Based on operating frequency requirements (e.g., high-frequency fast charging or low-frequency slow charging), the number of coil operating segments is switched, optimizing the inductance parameters of the LC resonant circuit, significantly reducing AC impedance, improving energy transfer efficiency, and reducing heat generation. The segmented coil structure combined with a full-bridge drive circuit supports operation over a wide frequency range (e.g., 100kHz-2MHz), adapting to the resonant frequencies of different devices and expanding the application scenarios of wireless charging systems.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic block diagram of the wireless charging circuit provided in one embodiment of this application; Figure 2 This is a circuit diagram of the first type of wireless charging circuit provided in an embodiment of this application; Figure 3 This is a circuit diagram of the second wireless charging circuit provided in one embodiment of this application; Figure 4 This is a schematic block diagram of the structure of an electronic device provided in an embodiment of this application.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be understood that this application can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0024] To fully understand this application, detailed structures and steps will be presented in the following description to illustrate the technical solutions proposed in this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0025] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other. In the field of wireless charging technology, the diversification of smart devices (such as smartphones, smartwatches, and wireless earphones) has placed higher demands on the compatibility of the transmitting coil. Traditional wireless charging solutions suffer from the following technical bottlenecks: 1. Poor compatibility with multiple devices: In existing technologies, separate coils, drive circuits, and demodulation circuits are typically used to meet the charging needs of different devices (such as mobile phones and watches). For example, mobile phone charging requires a larger coil to meet power transmission requirements, while watch charging requires a smaller coil due to size limitations. The differences in the number of turns, inductance, and resonant frequency between the two coils are significant, making it impossible for traditional solutions to achieve multi-device compatibility with a single coil. Multiple independent circuits must be relied upon, resulting in high costs and complex structures.

[0026] 2. Low frequency adaptation efficiency: Different devices operate at different frequencies (e.g., mobile phones may operate at lower frequencies, while fast charging for watches may require higher frequencies). The fixed inductance of a traditional single coil results in significant differences in AC impedance at different frequencies. As the frequency increases, the coil impedance increases, and the energy transfer efficiency decreases significantly, failing to meet the high-efficiency charging needs of all scenarios.

[0027] 3. Structural design limitations: Existing coils are typically single, continuously wound structures, lacking a flexible mechanism for adjusting inductance. Although some solutions attempt to adjust resonant parameters by switching external capacitors, the coil's inductance itself is fixed, failing to fundamentally solve the impedance matching problem at different frequencies, and its adaptability remains limited by the inherent parameters of the coil.

[0028] Therefore, there is an urgent need for a circuit to solve at least one of the above problems.

[0029] To resolve the above issues, please refer to [link / reference needed]. Figures 1 to 3This application provides a wireless charging circuit, including a full-bridge drive circuit 11, an LC resonant circuit 12, and a coil switching switch 13. The full-bridge drive circuit 11 includes at least a first drive node and a second drive node. The LC resonant circuit 12 is connected between the first drive node and the second drive node. The LC resonant circuit 12 includes a transmitting coil 121, which includes a first coil segment and a second coil segment. One end of the coil switching switch 13 is connected to a terminal between the first coil segment and the second coil segment, and the other end is connected to the first drive node.

[0030] The wireless charging circuit mainly consists of three parts: a full-bridge drive circuit 11, which includes four switching devices (such as MOSFETs) to form two sets of complementary switching groups (the first set of switches and the fourth set of switches form one group, and the second set of switches and the third set of switches form another group). The circuit generates a high-frequency drive signal by alternating switching and outputs it to the first drive node and the second drive node to drive the LC resonant circuit 12.

[0031] LC resonant circuit 12 includes a transmitting coil 121. The transmitting coil 121 employs a special winding method, with a terminal extending from the center tap, dividing the coil into a physically continuous but electrically separable first coil segment (the part near the first driving node) and a second coil segment (the part near the second driving node). A resonant capacitor can be connected between the second driving node and ground (or, depending on the circuit structure, between the two driving nodes) to form an LC resonant circuit with the transmitting coil 121. A coil switching switch 13 is connected at one end to the center tap terminal of the transmitting coil 121 and at the other end to the first driving node of the full-bridge driving circuit 11. An external control signal controls the closing or opening state of this switch, enabling dynamic adjustment of the inductance of the transmitting coil 121.

[0032] The inductance switching mechanism includes the following: When the coil switching switch 13 is open, the first coil segment and the second coil segment of the transmitting coil 121 are connected in series, and the overall inductance is the sum of the inductances of the two segments (i.e., the complete coil). This is suitable for scenarios requiring a larger inductance (such as mobile phone charging, corresponding to a lower operating frequency). When the coil switching switch 13 is closed, the first driving node is directly connected to the center tap terminal through the closed coil switching switch 13. At this time, only the first coil segment is connected to the resonant circuit (the second coil segment is short-circuited or bypassed), and the inductance is only the inductance of the first coil segment. This is suitable for scenarios requiring a smaller inductance (such as fast charging of a watch, corresponding to a higher operating frequency).

[0033] When the receiving device is detected to be a mobile phone, the control coil switching switch 13 is turned off, and the transmitting coil 121 operates with full inductance. With the corresponding resonant capacitor, the LC resonant frequency is matched with the low-frequency operating range of the mobile phone receiver, reducing AC impedance and improving energy transmission efficiency.

[0034] When the receiving device is detected to be a watch, the control coil switching switch 13 is closed, and the transmitting coil 121 operates with partial inductance. The resonant capacitor is adjusted synchronously (this can be achieved through an additional capacitor switching switch) so that the LC resonant frequency matches the high-frequency operating range of the watch receiver, optimizing impedance matching at high frequencies and reducing energy loss.

[0035] It should be noted that the parameters can be adjusted for different mobile phones / watches, and the circuit provided in this application can also charge any type of electronic device. Those skilled in the art can adjust the parameters arbitrarily according to the actual type of device being charged, and the embodiments of this application do not limit this.

[0036] The full-bridge drive circuit 11 generates a high-frequency alternating voltage between the first and second drive nodes through the alternating conduction of two sets of switches, which excites the LC resonant circuit 12 to generate a resonant magnetic field. The state of the coil switching switch 13 determines the inductance of the coil connected to the resonant circuit. Combined with the parameter adjustment of the resonant capacitor (optional configuration), the entire system can achieve the optimal resonant state at the operating frequency of different devices, realizing compatible charging of multiple devices (different frequencies and power requirements) by a single coil.

[0037] The provided wireless charging circuit has the following technical advantages: 1. Single coil adaptability to multiple scenarios: By winding with a center tap and switching, it can be compatible with the inductance requirements of different devices without the need for an independent coil, simplifying the circuit structure and reducing costs.

[0038] 2. Dynamic inductance adjustment: Directly changes the effective number of turns of the coil. Compared with traditional fixed inductance coils, it can more accurately match the impedance requirements at different frequencies and improve the energy transmission efficiency across the entire frequency band.

[0039] 3. Modular expansion: It can be further integrated with resonant capacitor switching circuit (such as multiple capacitors connected in parallel through a switch), combined with coil inductance switching, to achieve compatibility with more device types (such as wireless headphones), and expand application scenarios.

[0040] Through the above structure, the wireless charging circuit breaks through the limitations of traditional solutions in terms of coil winding method and circuit control, effectively solving the problems of poor compatibility of multiple devices and low frequency adaptation efficiency, and providing an innovative solution for the miniaturization and cost reduction of wireless charging devices.

[0041] In some embodiments, the transmitting coil 121 forms the first coil segment and the second coil segment by winding with a center tap, and the coil switching switch 13 is connected to the terminal corresponding to the center tap.

[0042] The transmitting coil 121 is wound with a center tap, and a terminal is led out from the physical midpoint of the coil, dividing the coil into an electrically independent and switchable first coil segment (the part near the first drive node of the full-bridge drive circuit 11) and a second coil segment (the part near the second drive node). One end of the coil switching switch 13 is connected to the center tap terminal, and the other end is connected to the first drive node, controlling the series connection or separation of the two coil segments by switching on and off.

[0043] The coil is wound with enameled wire on a toroidal or planar frame. When half of the total number of turns is reached (or the proportion required by the design), a terminal (center tap) is led out from that position. The remaining turns continue to be wound to the end, forming two coil segments: the first coil segment runs from the first drive node connection end to the center tap terminal, with N1 turns; the second coil segment runs from the center tap terminal to the second drive node connection end, with N2 turns (N1 + N2 = total number of turns). Switch connection: One end of the coil switch 13 (such as a MOSFET or relay) is soldered to the center tap terminal, and the other end is soldered to the first drive node of the full-bridge drive circuit 11.

[0044] The inductance switching logic includes: when the switch is open, the first coil segment and the second coil segment are connected in series, and the total inductance L = L1.2 + L1.1 (complete coil); when the switch is closed, the first drive node is directly connected to the center tap through the switch, the second coil segment is bypassed, and only the first coil segment is connected to the resonant circuit, with an inductance L = L1.2.

[0045] In some embodiments, the LC resonant circuit 12 further includes a resonant capacitor connected between the second coil segment and the second driving node.

[0046] The LC resonant circuit 12 includes a resonant capacitor connected between the second coil segment and the second drive node of the full-bridge drive circuit 11, forming an LC resonant circuit with the transmitting coil 121. By matching the capacitance with the coil inductance, the system resonates at the target frequency.

[0047] Resonant capacitor connection: One end of the resonant capacitor C is connected to the end of the second coil segment (non-center tap end), and the other end is connected to the second driving node of the full-bridge drive circuit 11 (i.e., the midpoint of the second group of switches in the full-bridge circuit).

[0048] When coil switch 13 is open, the circuit is: first drive node → first coil segment → center tap terminal → second coil segment → resonant capacitor C → second drive node, forming an LC series resonant circuit with a resonant frequency of [missing information]. When coil switch 13 is closed, the circuit is: first drive node → switch → center tap terminal (short-circuiting the second coil segment) → first coil segment → resonant capacitor C → second drive node. At this time, the inductance is L1.2, and the resonant frequency is... The capacitor selection is based on the operating frequency of the target device (e.g., a large capacitor is selected for low-frequency scenarios in mobile phones, and a small capacitor is selected for high-frequency scenarios in watches), choosing a fixed capacitance value or an adjustable capacitor in conjunction with other embodiments.

[0049] In some embodiments, the LC resonant circuit 12 includes a plurality of resonant capacitors connected in parallel and a plurality of resonant switches, wherein the resonant capacitors are connected in series with the resonant switches.

[0050] The LC resonant circuit 12 includes multiple resonant capacitors connected in parallel, each capacitor connected in series with an independent resonant switch. By controlling the on and off states of different switches, the combination of capacitors connected to the circuit is switched, thereby achieving dynamic adjustment of the resonant capacitor value. Combined with the switching of coil inductance, the resonant frequency of different devices can be precisely matched.

[0051] The capacitor array configuration includes resonant capacitors C1, C2, ..., Cn, each with a different capacitance value (e.g., C1=100nF, C2=47nF, C3=22nF). Each capacitor is connected in series with a resonant switch (e.g., S6, S7, ..., Sn+5, a MOSFET or a relay). The other ends of all the capacitor switches are connected in parallel and then connected to the end of the second coil segment or the second drive node (depending on the circuit structure).

[0052] The switching logic works by disconnecting coil switching switch 13 (enabling the complete coils L1.2+L1.1) when the receiving device is detected as a mobile phone (in a low-frequency scenario), and simultaneously turning on the resonant switch corresponding to the large capacitor (such as C1), thus... ;) Matching the phone frequency; When the watch is detected (high-frequency scenario), the coil switching switch 13 is closed (L1 is enabled), and the resonant switch of the corresponding small capacitor (such as C2+C3 in parallel) is turned on, making To meet the high-frequency requirements of watches, a wider frequency range can be covered through the combination of multiple capacitors, improving the accuracy of multi-device compatibility.

[0053] In some embodiments, the full-bridge drive circuit 11 includes at least a first switch group and a second switch group, wherein the first switch group forms the first drive node and the second switch group forms the second drive node.

[0054] The full-bridge drive circuit 11 consists of a first switch group and a second switch group. Each group contains at least two switching transistors (such as upper and lower bridge arms). The midpoint of the first switch group is the first drive node, and the midpoint of the second switch group is the second drive node. By alternately turning on the two sets of switches, a high-frequency alternating voltage is generated between the two drive nodes.

[0055] The first switching group includes an upper bridge switching transistor S1 (such as an N-type MOSFET) and a lower bridge switching transistor S2. The drain of S1 is connected to a preset power supply PVIN, the source is connected to the drain of S2, the source of S2 is grounded, and the first driving node (SW1) is located between S1 and S2. If the second switch group includes an upper bridge switch S3 and a lower bridge switch S4, the connection method is the same as that of the first switch group, and the second drive node (SW2) is located between S3 and S4.

[0056] When S1 and S4 are on and S2 and S3 are off, the current path is PVIN→S1→SW1→LC resonant circuit 12→SW2→S4→ground, with SW1 at a high level and SW2 at a low level. When S2 and S3 are on and S1 and S4 are off, the current path is PVIN→S3→SW2→LC resonant circuit 12→SW1→S2→ground, with SW2 at a high level and SW1 at a low level. The two sets of switches are turned on alternately, generating a high-frequency square wave between SW1 and SW2, which drives the LC resonant circuit 12.

[0057] In some embodiments, the first switch group includes at least two switching transistors, and the first drive node is disposed between the two switching transistors.

[0058] The first switching group includes at least two switching transistors (upper bridge and lower bridge), and the first driving node is located between the two switching transistors as one of the output terminals of the full-bridge driving circuit 11, and is connected to the first coil segment of the transmitting coil 121.

[0059] The switching configuration includes: the first switching group consists of an upper bridge switching transistor S1 and a lower bridge switching transistor S2: the drain of S1 is connected to the DC power supply PVIN, and the source is connected to the drain of S2; the source of S2 is grounded, and the first driving node (SW1) is directly connected to the common terminal (source / drain connection) of S1 and S2.

[0060] Signal output: When S1 is on and S2 is off, the voltage at node SW1 is PVIN (ignoring the tube voltage drop); when S1 is off and S2 is on, the voltage at node SW1 is 0V (ground potential); by controlling the alternating conduction of S1 and S2 through PWM, a high-frequency pulse signal is generated at node SW1 to drive the first coil segment of LC resonant circuit 12.

[0061] In some embodiments, the second switch group includes at least two switching transistors, and the second drive node is disposed between the two switching transistors.

[0062] The structure of the second switch group is symmetrical to that of the first switch group, and includes at least two switching transistors. The second drive node is located between the two switching transistors and serves as another output terminal of the full-bridge drive circuit 11, connected to the resonant capacitor or the second coil segment.

[0063] Symmetrical switch group design: The second switch group consists of an upper bridge switch S3 and a lower bridge switch S4, and the connection method is completely symmetrical with the first switch group: the drain of S3 is connected to PVIN, and the source is connected to the drain of S4; the source of S4 is grounded, and the second drive node (SW2) is located between S3 and S4.

[0064] Complementary drive: The second switch group and the first switch group are strictly complementary in conduction: when the first switch group S1 is on and S2 is off, the second switch group S4 is on and S3 is off (corresponding to the first drive mode); when the first switch group S2 is on and S1 is off, the second switch group S3 is on and S4 is off (corresponding to the second drive mode); ensuring that SW1 and SW2 are always reverse voltages to avoid power supply short circuit.

[0065] In some embodiments, the capacitance value of each of the resonant capacitors is different, and the number of the resonant switches is less than or equal to the number of the resonant capacitors.

[0066] The multiple resonant capacitors in the LC resonant circuit 12 have different capacitance values ​​(e.g., C1=10nF, C2=47nF, C3=100nF). Each capacitor is connected in series with an independent resonant switch. The number of switches is less than or equal to the number of capacitors (switches can be reused or multiplexers can be used). By combining different capacitors connected to the circuit, the resonant capacitance value can be flexibly adjusted.

[0067] Capacitor values ​​are configured in decimal or binary gradients (e.g., 10nF, 22nF, 47nF, 100nF), and various capacitance values ​​can be obtained by parallel connection (e.g., 10+22=32nF, 22+47=69nF).

[0068] The switch configuration strategy assigns an independent switch to each capacitor (e.g., S6 controls C1, S7 controls C2, and S8 controls C3), with the number of switches equal to the number of capacitors; or it uses multiplexed switches (e.g., single-pole multi-throw switches), with the number of switches less than the number of capacitors (e.g., one switch switches three capacitors, but only one capacitor can be connected at the same time).

[0069] Based on the frequency requirements of the receiving equipment, the microcontroller (MCU) outputs a control signal to turn on the capacitor switch with the corresponding capacitance value, which works in conjunction with the coil inductance switching to ensure that the LC resonant frequency accurately matches the equipment requirements.

[0070] In some embodiments, the first switch group and the second switch group are respectively connected between a preset power supply and a preset ground terminal. The full-bridge drive circuit 11 includes a first drive mode and a second drive mode. In the first drive mode, the preset power supply is connected to the first drive node and the second drive node is connected to the preset ground terminal. In the second drive mode, the preset power supply is connected to the second drive node and the first drive node is connected to the preset ground terminal.

[0071] The full-bridge drive circuit 11 is connected to a preset power supply (such as the DC bus PVIN) and a preset ground terminal (GND), and has two drive modes: the first drive mode conducts the preset power supply to the first drive node and the second drive node to the ground terminal; the second drive mode conducts the preset power supply to the second drive node and the first drive node to the ground terminal; by switching between the two modes alternately, a high-frequency alternating voltage is generated between the two drive nodes to excite the LC resonant circuit 12.

[0072] The drains of the upper bridge switching transistors (S1, S3) of the full-bridge drive circuit 11 are connected to the preset power supply PVIN (such as 5V, 12V, selected according to power requirements); the sources of the lower bridge switching transistors (S2, S4) are connected to the preset ground terminal GND.

[0073] First driving mode: S1 and S4 are on, S2 and S3 are off, and the current path is PVIN→S1→SW1→LC resonant circuit 12→SW2→S4→GND. At this time, SW1=PVIN and SW2=0V. Second driving mode: S2 and S3 are on, S1 and S4 are off, and the current path is PVIN→S3→SW2→LC resonant circuit 12→SW1→S2→GND. At this time, SW2=PVIN and SW1=0V. The two modes are switched alternately at high frequency (e.g., 100kHz~2MHz), forming a square wave voltage between SW1 and SW2. Its frequency determines the operating frequency of LC resonant circuit 12. With the switching of coil inductance and capacitance, multi-device compatibility is achieved.

[0074] This application provides a wireless charging circuit that dynamically adjusts the effective inductance via a coil switching switch 13. A single coil can be compatible with the charging needs of different devices such as mobile phones and watches, eliminating the need for independent coils and drive circuits, thus reducing hardware costs and structural complexity. Based on operating frequency requirements (such as high-frequency fast charging or low-frequency slow charging), the number of coil operating segments is switched, optimizing the inductance parameters of the LC resonant circuit 12, significantly reducing AC impedance, improving energy transfer efficiency, and reducing heat generation. The segmented coil structure combined with the full-bridge drive circuit 11 supports operation over a wide frequency range (such as 100kHz-2MHz), adapting to the resonant frequencies of different devices and expanding the application scenarios of the wireless charging system.

[0075] Please refer to the foregoing embodiments. Figure 4, Figure 4 This is a schematic block diagram of an electronic device 100 provided for some embodiments of this application. The electronic device 100 includes the wireless charging circuit 10 provided in any embodiment of this application.

[0076] In some embodiments, the provided wireless charging circuit 10 includes a wireless charging circuit provided in this application embodiment, comprising a full-bridge drive circuit 11, an LC resonant circuit 12, and a coil switching switch 13. The full-bridge drive circuit 11 includes at least a first drive node and a second drive node. The LC resonant circuit 12 is connected between the first drive node and the second drive node. The LC resonant circuit 12 includes a transmitting coil 121, which includes a first coil segment and a second coil segment. One end of the coil switching switch 13 is connected to a terminal between the first coil segment and the second coil segment, and the other end is connected to the first drive node.

[0077] The specific principles and implementation methods of the electronic devices provided in this application are similar to those of the wireless charging circuits in the aforementioned embodiments, and will not be repeated here.

[0078] It should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. It should be understood that when an element or layer is referred to as “on,” “adjacent to,” “connected to,” or “coupled to” other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as “directly on,” “directly adjacent to,” “directly connected to,” or “directly coupled to” other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion.

[0079] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0080] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0081] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0082] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wireless charging circuit, characterized in that, include: A full-bridge drive circuit, wherein the full-bridge drive circuit includes at least a first drive node and a second drive node; An LC resonant circuit is connected between the first driving node and the second driving node. The LC resonant circuit includes a transmitting coil, which includes a first coil segment and a second coil segment. A coil switching switch, one end of which is connected to the terminal between the first coil segment and the second coil segment, and the other end of which is connected to the first drive node.

2. The wireless charging circuit according to claim 1, characterized in that, The transmitting coil is wound with a center tap to form the first coil segment and the second coil segment, and the coil switching switch is connected to the terminal corresponding to the center tap.

3. The wireless charging circuit according to claim 1, characterized in that, The LC resonant circuit also includes a resonant capacitor connected between the second coil segment and the second driving node.

4. The wireless charging circuit according to claim 1, characterized in that, The LC resonant circuit includes multiple resonant capacitors connected in parallel and multiple resonant switches, with the resonant capacitors connected in series with the resonant switches.

5. The wireless charging circuit according to claim 1, characterized in that, The full-bridge drive circuit includes at least a first switch group and a second switch group, wherein the first switch group forms the first drive node and the second switch group forms the second drive node.

6. The wireless charging circuit according to claim 5, characterized in that, The first switch group includes at least two switching transistors, and the first drive node is disposed between the two switching transistors.

7. The wireless charging circuit according to claim 5, characterized in that, The second switch group includes at least two switching transistors, and the second drive node is disposed between the two switching transistors.

8. The wireless charging circuit according to claim 4, characterized in that, Each of the resonant capacitors has a different capacitance value, and the number of the resonant switches is less than or equal to the number of the resonant capacitors.

9. The wireless charging circuit according to claim 5, characterized in that, The first switch group and the second switch group are respectively connected between a preset power supply and a preset ground terminal. The full-bridge drive circuit includes a first drive mode and a second drive mode. In the first drive mode, the preset power supply is connected to the first drive node and the second drive node is connected to the preset ground terminal. In the second drive mode, the preset power supply is connected to the second drive node and the first drive node is connected to the preset ground terminal.

10. An electronic device, characterized in that, The electronic device includes the wireless charging circuit according to any one of claims 1-9.

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