Wireless charging circuit, wireless charging module and electronic device

Abstract

The present application relates to the technical field of wireless charging, and discloses a wireless charging circuit, a wireless charging module and an electronic device. The wireless charging circuit comprises a first switching device, a first unidirectional device, a first capacitor, and a first coil. When the first switching device is in an on state, the alternating current output by an alternating current power supply passes through the first switching device or the first unidirectional device, and radiates electromagnetic energy to a space by means of the first capacitor and the first coil; and when the first switching device is in an off state, the alternating current power supply charges the first capacitor to a preset voltage by means of the first unidirectional device, and stops radiating electromagnetic energy to the space. On the basis of the solution of the present application, the on and off of a wireless charging path can be realized by means of one switching device, one unidirectional device and a capacitor, so that the wireless charging circuit uses fewer electronic devices, has lower cost and smaller volume, and is therefore more suitable for the development trend of miniaturization and low cost of electronic devices in the future.

Description

Wireless charging circuits, wireless charging modules and electronic devices

[0001] This application claims priority to Chinese patent application filed on September 2, 2024, with application number 202411216984.7 and entitled "Wireless charging circuit, wireless charging module and electronic device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of wireless charging technology, specifically to a wireless charging circuit, a wireless charging module, and an electronic device. Background Technology

[0003] With the continuous advancement of technology, in order to improve the convenience of users using electronic devices, in addition to the functions of the electronic devices themselves, the charging methods of electronic devices are also constantly being innovated. For example, for styluses or keyboards used with tablets, in addition to charging them via wired connection through the tablet, they can also be charged wirelessly through the tablet.

[0004] When a tablet wirelessly charges a stylus or keyboard, only one device can be charged at a time. Since the stylus and keyboard have different wireless charging paths, a wireless charging circuit is needed to control the tablet's charging path, allowing only one path to be active at a time. However, existing wireless charging circuits typically use dual MOSFETs to control the on / off state of the charging path, requiring more electronic components, resulting in higher overall cost and larger size, which is not suitable for the trend towards miniaturization and lower cost in electronic devices.

[0005] Therefore, a new solution is urgently needed to address the aforementioned problems. Summary of the Invention

[0006] This application provides a wireless charging circuit, a wireless charging module, and an electronic device, which can realize the conduction and cutoff of the wireless charging path through a single switching device, a unidirectional device, and a capacitor. This reduces the number of electronic components used in the wireless charging circuit, resulting in lower cost and smaller size, making it more suitable for the future trend of miniaturization and low cost in electronic devices.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] In a first aspect, a wireless charging circuit is provided, including a first switching device, a first unidirectional device, a first capacitor, and a first coil. A first terminal of the first switching device is connected to a first power supply terminal of an AC power source and a first terminal of the first unidirectional device. A second terminal of the first switching device is connected to a first plate of the first capacitor and a second terminal of the first unidirectional device. A second plate of the first capacitor is connected to a first terminal of the first coil. A second terminal of the first coil is connected to a second power supply terminal of the AC power source. When the first switching device is in a conducting state, the AC power output from the AC power source passes through the first switching device or the first unidirectional device and radiates electromagnetic energy into space through the first capacitor and the first coil. When the first switching device is in a de-energized state, the AC power source charges the first capacitor to a preset voltage through the first unidirectional device and stops radiating electromagnetic energy into space.

[0009] In this embodiment, the wireless charging circuit is controlled to turn on and off based on the on / off state of the first switching device, the first unidirectional device, and the first capacitor. When the first switching device is on, the current output from the AC power supply can pass through the first switching device or the first unidirectional device, and radiate electromagnetic energy into space through the first capacitor and the first coil, thereby wirelessly charging the terminal device wirelessly connected to the wireless charging circuit. When the first switching device is off, the AC power output from the AC power supply can charge the first capacitor to a preset voltage through the first unidirectional device, and stop radiating electromagnetic energy into space, thereby stopping wireless charging of the terminal device wirelessly connected to the wireless charging circuit. Therefore, this wireless charging circuit not only realizes the on / off state of the wireless charging path, but also requires fewer electronic components, resulting in lower overall cost and smaller size, making it more suitable for the trend of miniaturization and low cost of electronic devices.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the wireless charging circuit includes a first PMOSFET, the first PMOSFET including a transistor structure and a parasitic diode, the first switching device being a transistor structure, and the first unidirectional device being a parasitic diode.

[0011] In this implementation, a single first PMOSFET can simultaneously include a first switching device and a first unidirectional device. Specifically, the transistor structure serves as the first switching device, and the parasitic diode serves as the first unidirectional device. When the transistor structure is in the ON state, electromagnetic energy is radiated into space through the transistor structure, the parasitic diode, the first capacitor, and the first coil. When the transistor structure is in the OFF state, the parasitic diode charges the first capacitor to a preset voltage, and the radiation of electromagnetic energy into space ceases.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the wireless charging circuit further includes a second switching device, the first terminal of which is connected to the control terminal of the first switching device, and the second terminal of which is grounded; when the second switching device is in the conducting state, the first switching device is also in the conducting state.

[0013] In this implementation, the second switching device acts as an auxiliary device. When the second switching device is turned on, the first switching device is also turned on, thereby putting the wireless charging circuit in a conducting state. When the second switching device is turned off, the first switching device is also turned off, thereby putting the wireless charging circuit in a disconnected state.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the second switching device includes a second NMOSFET, the drain of the second NMOSFET being connected to the control terminal of the first switching device, and the source of the second NMOSFET being grounded.

[0015] In this implementation, the second NMOSFET is used as the second switching device. The second NMOSFET is controlled to be either turned on or off according to the control signal received at its gate, thereby controlling the first switching device to be turned on or off.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the wireless charging circuit further includes a first resistor and a second resistor, wherein the first end of the first resistor and the first end of the second resistor are both connected to the control terminal of the first switching device, and the second end of the second resistor is connected to the second terminal of the first switching device.

[0017] In this implementation, the first resistor and the second resistor serve as voltage divider resistors, and the voltage between the control terminal and the second terminal of the first switching device is adjusted according to the resistance ratio of the first resistor and the second resistor.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the wireless charging circuit further includes a second capacitor, the first end of which is connected to the control terminal of the first switching device, and the second end of which is connected to the second terminal of the first switching device.

[0019] In this implementation, the second capacitor serves as a voltage regulator, used to regulate the voltage between the control terminal and the second terminal of the first switching device.

[0020] Secondly, a wireless charging module is provided, including a control module and multiple wireless charging circuits; the control module is connected to the multiple wireless charging circuits respectively; the control module is used to control one of the multiple wireless charging circuits to be turned on; when the wireless charging circuit is in the turned-on state, it is used to radiate electromagnetic energy into space.

[0021] In this embodiment, the control module outputs a control signal to turn on one of the multiple wireless charging circuits while turning off the others. The wireless charging circuit is turned on according to the control signal from the control module and radiates electromagnetic energy into space to wirelessly charge the corresponding terminal device. This effectively reduces the number of electronic components used in the wireless charging module, resulting in lower cost and smaller size. Therefore, it is more suitable for the future trend of miniaturization and low cost in electronic devices.

[0022] In conjunction with the second aspect, in some implementations of the second aspect, the wireless charging circuit includes at least one of a stylus charging circuit and a wireless keyboard charging circuit, wherein only one of the stylus charging circuit and the wireless keyboard charging circuit is turned on at a time.

[0023] In this embodiment, when the wireless charging circuit includes a stylus charging circuit and the stylus charging circuit is turned on, AC power is used to wirelessly charge the stylus through the stylus charging circuit. When the wireless charging circuit includes a wireless keyboard charging circuit and the wireless keyboard charging circuit is turned on, AC power is used to wirelessly charge the wireless keyboard through the wireless keyboard charging circuit. When the wireless charging circuit includes both a stylus charging circuit and a wireless keyboard charging circuit, only one of the stylus charging circuit and the wireless keyboard charging circuit is turned on at a time, and AC power is used to wirelessly charge the stylus through the stylus charging circuit, or AC power is used to wirelessly charge the wireless keyboard through the wireless keyboard charging circuit.

[0024] In conjunction with the second aspect, in some implementations of the second aspect, the wireless charging module further includes a first packaging structure and a second packaging structure, wherein one of the first switching devices in the two wireless charging circuits is encapsulated within the first packaging structure, and the other of the first switching devices in the two wireless charging circuits is encapsulated within the second packaging structure.

[0025] In this embodiment, the first switching devices in the two wireless charging circuits can be independently packaged in a first package structure and a second package structure, respectively. For example, the two first switching devices can be two separately packaged PMOSFETs, each connected to one of the two wireless charging circuits.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, the wireless charging module also includes a third packaging structure, in which the first switching devices in both wireless charging circuits are encapsulated within the third packaging structure.

[0027] In this embodiment, the first switching devices in the two wireless charging circuits are packaged together in a third package structure. For example, the two first switching devices can be a combined package of dual PMOSFETs, which are respectively connected to the two wireless charging circuits.

[0028] Thirdly, an electronic device is provided, including a wireless charging circuit or a wireless charging module, and the electronic device also includes a battery. The wireless charging circuit or wireless charging module is used to convert the electrical energy of the battery into electromagnetic energy and radiate it into space.

[0029] In the embodiments of this application, the wireless charging circuit or wireless charging module can realize the conduction and cutoff of the wireless charging path through a switching device, a unidirectional device and a capacitor, so as to convert the electrical energy stored in the battery into electromagnetic energy and emit it into space, thereby effectively reducing the electronic components used in electronic devices, reducing the cost of electronic devices, shrinking the size of electronic devices, and making them more suitable for the development trend of miniaturization and low cost of electronic devices. Attached Figure Description

[0030] Figure 1 is a schematic diagram of a wireless charging scenario applicable to an embodiment of this application;

[0031] Figure 2 is a schematic diagram of another wireless charging scenario applicable to an embodiment of this application;

[0032] Figure 3 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0033] Figure 4 is a schematic diagram of the structure of a wireless charging module provided in an embodiment of this application;

[0034] Figure 5 is a circuit diagram of a wireless charging module provided in an embodiment of this application;

[0035] Figure 6 is a circuit diagram of a wireless charging circuit provided in an embodiment of this application;

[0036] Figure 7 is a circuit diagram of another wireless charging circuit provided in this application embodiment;

[0037] Figure 8 is a circuit diagram of another wireless charging circuit provided in this application embodiment;

[0038] Figure 9 is a circuit diagram of another wireless charging circuit provided in this application embodiment;

[0039] Figure 10 is a circuit diagram of another wireless charging circuit provided in this application embodiment;

[0040] Figure 11 is a circuit diagram of another wireless charging circuit provided in this application embodiment;

[0041] Figure 12 is a schematic diagram of the structure of a wireless charging module provided in another embodiment of this application;

[0042] Figure 13 is a circuit diagram of another wireless charging module provided in this application embodiment;

[0043] Figure 14 is a simulation waveform diagram of a wireless charging module provided in an embodiment of this application;

[0044] Figure 15 is a measured waveform diagram of a wireless charging module provided in an embodiment of this application;

[0045] Figure 16 shows a hardware system of a terminal device provided in an embodiment of this application. Detailed Implementation

[0046] The technical solutions in the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; the word "and / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0047] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0048] To facilitate understanding of the embodiments of this application, the relevant concepts involved in the embodiments of this application will be briefly explained first.

[0049] 1. Wireless charging technology

[0050] In the field of communications, wireless charging technology generally refers to the technology of charging electrical devices through electromagnetic fields or waves without physical wires. Specifically, wireless charging can be categorized into electromagnetic induction, electromagnetic resonance, and radio wave charging. Electromagnetic induction typically uses a primary and secondary coil to induce current, transferring energy from the transmitting end to the receiving end. However, the transmission distance of electromagnetic induction is generally short, and energy loss during charging gradually increases with the transmission distance. Examples include wireless charging of mobile phones or wireless charging of styluses or keyboards on tablets. Electromagnetic resonance typically uses two objects with the same vibration frequency to efficiently transfer energy. When the transmitter and receiver vibrate at the same frequency, the receiver obtains energy from the electromagnetic field generated by the transmitter and converts it into current to power or charge mobile devices. An example is the wireless charging process of most electric vehicles. Radio wave charging typically uses a rectifier circuit to convert electromagnetic waves into electrical energy to charge electrical devices.

[0051] 2. Metal-oxide-semiconductor field-effect transistor (MOSFET), hereinafter referred to as "MOS transistor".

[0052] In the field of communications, a MOSFET (Metal-Oxide-Semiconductor Transistor) is a voltage-driven semiconductor device. A MOSFET typically has three electrodes: a gate (G), a source (S), and a drain (D). Based on their semiconductor structure, MOSFETs can be classified into PMOS (Positive-Metal-Oxide-Semiconductor) and NMOS (Negative-Metal-Oxide-Semiconductor) transistors. In general electronic circuits, MOSFETs are commonly used in amplifier circuits or switching circuits. As a voltage-controlled element, a MOSFET conducts through its source and drain when the voltage applied to its gate exceeds a preset value. For example, when the voltage received at the gate of an NMOS transistor is greater than the preset value, the source and drain of the NMOS transistor conduct; when the voltage received at the gate is not greater than the preset value, the source and drain of the NMOS transistor are cut off. Similarly, when the voltage received at the gate of a PMOS transistor is less than the preset value, the source and drain of the PMOS transistor conduct; when the voltage received at the gate is not less than the preset value, the source and drain of the PMOS transistor are cut off.

[0053] The above is a brief introduction to the terms used in the embodiments of this application, and will not be repeated below.

[0054] The application scenarios and the structure of the electronic devices used in the embodiments of this application will be introduced below with reference to Figures 1 to 4.

[0055] Figure 1 is a schematic diagram of a wireless charging scenario applicable to an embodiment of this application.

[0056] As shown in Figure 1, a user can wirelessly charge a stylus 20 using an electronic device 10. When the stylus 20 is within a preset distance of the electronic device 10 and is recognized and connected by the electronic device 10, the electronic device 10 can wirelessly charge the stylus 20. When the stylus 20 is beyond the preset distance of the electronic device 10, the electronic device 10 stops wirelessly charging the stylus 20. This application does not specifically limit the type of electronic device 10. In some embodiments, the electronic device 10 can be a mobile phone, wearable device (e.g., smart bracelet, smartwatch, headphones, etc.), tablet computer, laptop computer, handheld computer, ultra-mobile personal computer (UMPC), cellular phone, personal digital assistant (PDA), augmented reality (AR) / virtual reality (VR) device, or other IoT (Internet of Things) devices, as well as devices such as a television, large screen, printer, and projector. For ease of understanding, the following embodiments use a tablet computer as an example for illustrative purposes.

[0057] Figure 2 is a schematic diagram of another wireless charging scenario applicable to an embodiment of this application.

[0058] As shown in Figure 2, the user can wirelessly charge the wireless keyboard 30 using the electronic device 10. When the wireless keyboard 30 is within a preset distance of the electronic device 10 and is recognized and connected by the electronic device 10, the electronic device 10 can wirelessly charge the wireless keyboard 30. When the wireless keyboard 30 is further away from the electronic device 10, the electronic device 10 stops wirelessly charging the wireless keyboard 30.

[0059] Figure 3 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0060] As shown in Figure 3, the electronic device 10 may include a central processing unit (CPU) 100, a wireless charging module 200, and a battery 300, etc. These devices can be coupled to each other through various interconnect buses or other electrical connection methods. For example, the wireless charging module 200 is electrically connected to the CPU 100 and the battery 300, respectively, and the wireless charging module 200 is also wirelessly connected to the stylus 20 and the wireless keyboard 30, respectively.

[0061] The Central Processing Module (CPU) 100 is one of the main components of a personal computer and a core part of it. Its primary function is to interpret computer instructions and process data within the computer software. All operations in a personal computer are handled by the CPU, which is responsible for reading, decoding, and executing instructions. A program is a sequence of instructions, and executing a program involves executing those instructions one by one. Once the program is loaded into main memory, the CPU automatically reads and executes instructions from main memory. Furthermore, the function of an instruction is often achieved by a series of operations performed by components within the personal computer. The CPU generates corresponding operation control signals based on the function of the instruction and sends them to the appropriate components, thereby controlling these components to perform actions as required by the instruction.

[0062] For example, the central processing module 100 may include an arithmetic logic unit, a register unit, an arithmetic logic unit, and a control unit. The arithmetic logic unit can perform fixed-point or floating-point arithmetic operations, shift operations, and logical operations, as well as address operations and translations. The register unit includes general-purpose registers, special-purpose registers, and control registers. The control unit is primarily responsible for decoding instructions and issuing control signals to complete the various operations required for each instruction.

[0063] The wireless charging module 200 is a charging module installed inside the electronic device 10. The wireless charging module 200 may include a wireless charging receiver unit and / or a wireless charging transmitter unit, both of which are connected to the central processing module 100. The wireless charging receiver unit senses external magnetic field energy through its receiving coil and converts it into electrical energy for storage in the battery 300. For example, when the electronic device 10 is a mobile phone, it can receive magnetic field energy from a wireless charger through the wireless charging receiver unit and wirelessly charge the phone, storing the electrical energy in the battery 300. The wireless charging transmitter unit transmits the electrical energy from the battery 300 to the outside world through its transmitting coil. For example, when the electronic device 10 is a tablet computer, it can convert the electrical energy from the battery 300 into magnetic field energy through the wireless charging transmitter coil of the wireless charging transmitter unit and transmit it to the outside world, thereby wirelessly charging the stylus 20 or the wireless keyboard 30. Correspondingly, the stylus 20 or the wireless keyboard 30 also has a wireless charging receiver coil inside to receive magnetic field energy and convert it into electrical energy for use by the stylus 20 or the wireless keyboard 30.

[0064] The wireless charging transmitter (TX) can be an electronic device with a wireless charging transmitter, such as a tablet computer. The wireless charging transmitter may include a first MCU, a power bridge, and a first LC resonant circuit. The first LC resonant circuit includes a transmitter coil and a transmitter capacitor; the transmitter coil can be equivalent to a transmitter inductor. The input of the wireless charging transmitter is a DC voltage, which is passed through the power bridge to generate an AC voltage, i.e., a square wave. The square wave is applied across the first LC resonant circuit to generate an AC current. This AC current passes through the transmitter coil to generate a magnetic field, thereby radiating magnetic field energy into space.

[0065] The wireless charging receiver (RX) can be an electronic device with wireless charging capabilities, such as a stylus or keyboard. The wireless charging receiver may include a second MCU, a rectifier bridge, a low dropout regulator (LDO), a charging chip, a battery, and a second LC resonant circuit. The second LC resonant circuit includes a receiver coil and a receiving capacitor. The receiver coil senses the energy of a spatial magnetic field, generating an alternating current in the second LC resonant circuit. This alternating current is converted into a direct current voltage by the rectifier bridge, and the DC voltage then charges the battery through the LDO and the charging chip.

[0066] It should be understood that the above is only an example of the structure of electronic device 10. Electronic device 10 may also include other subsystems or devices, which can be set and modified as needed. This application embodiment does not impose any restrictions on this.

[0067] Figure 4 is a schematic diagram of the structure of a wireless charging module provided in an embodiment of this application.

[0068] As shown in Figure 4, the wireless charging module 200 includes a wireless charging transmitter chip 201 and a wireless charging unit 202. The wireless charging unit 202 includes a stylus charging circuit 2021 and a wireless keyboard charging circuit 2022. Both the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022 are connected to the wireless charging transmitter chip 201.

[0069] The wireless charging transmitter chip 201 controls the operation of the wireless charging unit 202, thereby enabling the electrical energy stored in the battery 300 to charge the stylus 20 or the wireless keyboard 30 through the wireless charging unit 202. Exemplarily, the wireless charging transmitter chip 201 controls the stylus charging circuit 2021 to be turned on or off, to wirelessly charge the stylus 20 or stop wirelessly charging the stylus 20. The wireless charging transmitter chip 201 also controls the wireless keyboard charging circuit 2022 to be turned on or off, to wirelessly charge the wireless keyboard 30 or stop wirelessly charging the stylus.

[0070] When the stylus 20 approaches the electronic device 10 within a preset distance range, and the Hall sensor within the electronic device 10 detects the stylus 20, the wireless charging transmitter chip 201 controls the stylus charging circuit 2021 to establish a wireless charging path between the electronic device 10 and the stylus 20, thereby enabling the electronic device 10 to wirelessly charge the stylus 20. Similarly, when the wireless keyboard 30 approaches the electronic device 10 within a preset distance range, and the Hall sensor within the electronic device 10 detects the wireless keyboard 30, the wireless charging transmitter chip 201 controls the wireless keyboard charging circuit 2022 to establish a wireless charging path between the electronic device 10 and the wireless keyboard 30, thereby enabling the electronic device 10 to wirelessly charge the wireless keyboard 30.

[0071] The technical problems existing in the relevant technologies will be described in detail below with reference to Figure 5.

[0072] Figure 5 is a circuit diagram of a wireless charging module provided in an embodiment of this application.

[0073] As shown in Figure 5, the wireless charging module includes a wireless charging transmitter chip IC_Tx, a stylus charging circuit 2021, and a wireless keyboard charging circuit 2022. The stylus charging circuit 2021 includes a 21st PMOS transistor Q21, a 22nd PMOS transistor Q22, a first capacitor C1, and a first coil L1. The gate of the 21st PMOS transistor Q21 is connected to the gate of the 22nd PMOS transistor Q22. The drain of the 21st PMOS transistor Q21 is connected to the first power supply terminal of the wireless charging transmitter chip IC_Tx. The source of the 21st PMOS transistor Q21 is connected to the source of the 22nd PMOS transistor Q22. The gate of the 22nd PMOS transistor Q22 is connected in series with the first capacitor C1 and the first coil L1, and then connected to the second power supply terminal of the wireless charging transmitter chip IC_Tx.

[0074] When the gates of the 21st PMOS transistor Q21 and the 22nd PMOS transistor Q22 are connected to a stylus-on signal (i.e., a low-level signal), the stylus charging circuit 2021 is in the on state, radiating electromagnetic energy into space through a resonant circuit formed by the first capacitor C1 and the first coil L1, thereby wirelessly charging the stylus 20. When the gates of the 21st PMOS transistor Q21 and the 22nd PMOS transistor Q22 are connected to a stylus-off signal (i.e., a high-level signal), the stylus charging circuit 2021 is in the off state, stopping the radiation of electromagnetic energy into space, thereby stopping the wireless charging of the stylus 20.

[0075] The wireless keyboard charging circuit 2022 includes a 23rd PMOS transistor Q23, a 24th PMOS transistor Q24, a second capacitor C2, and a second coil L2. The gate of the 23rd PMOS transistor Q23 is connected to the gate of the 24th PMOS transistor Q24. The drain of the 23rd PMOS transistor Q23 is connected to the first power supply terminal of the wireless charging transmitter chip IC_Tx. The source of the 23rd PMOS transistor Q23 is connected to the source of the 24th PMOS transistor Q24. The gate of the 24th PMOS transistor Q24, the second capacitor C2, and the second coil L2 are connected in series and then connected to the second power supply terminal of the wireless charging transmitter chip IC_Tx.

[0076] When the gates of the 23rd PMOS transistor Q23 and the 24th PMOS transistor Q24 are connected to the wireless keyboard turn-on signal (i.e., a low-level signal), the wireless keyboard charging circuit 2022 is in the turn-on state, used to radiate electromagnetic energy into space through the resonant circuit formed by the second capacitor C2 and the second coil L2, thereby wirelessly charging the wireless keyboard 30. When the gates of the 23rd PMOS transistor Q23 and the 24th PMOS transistor Q24 are connected to the wireless keyboard turn-off signal (i.e., a high-level signal), the wireless keyboard charging circuit 2022 is in the turn-off state, stopping the radiation of electromagnetic energy into space, thereby stopping the wireless charging of the wireless keyboard 30.

[0077] However, in the wireless charging unit 202 mentioned above, both the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022 use two reverse-connected PMOS transistors to turn the wireless charging path on and off. This requires a lot of electronic components, and the overall cost and size of the wireless charging circuit are relatively high. Therefore, it is not suitable for the trend of miniaturization and low cost development of electronic devices 10.

[0078] In view of this, the present application provides a wireless charging circuit that can realize the conduction and cutoff of the wireless charging path through a switching device, a unidirectional device and a capacitor, thereby effectively reducing the number of electronic components used in the wireless charging circuit, reducing the cost of the wireless charging circuit and shrinking the size of the wireless charging circuit. Therefore, it is more suitable for the development trend of miniaturization and low cost of electronic devices.

[0079] The following section, in conjunction with Figures 6 to 15, provides a detailed description of the solutions provided in the embodiments of this application.

[0080] Figure 6 is a circuit diagram of a wireless charging circuit provided in an embodiment of this application.

[0081] As shown in Figure 6, in one embodiment provided in this application, the wireless charging circuit 600 includes a first switching device 601, a first unidirectional device 602, a first capacitor C1, and a first coil L1. The first switching device 601 has three terminals. The first terminal of the first switching device 601 is connected to the first power terminal of the AC power supply and the first terminal of the first unidirectional device 602, and is used to input AC power when the first power terminal of the AC power supply outputs AC power. The second terminal of the first switching device 601 is connected to the first plate of the first capacitor C1 and the second terminal of the first unidirectional device 602. The second plate of the first capacitor C1 is connected to the first terminal of the first coil L1. The second terminal of the first coil L1 is connected to the second power terminal of the AC power supply, and is used to output AC power. The third terminal of the first switching device 601 is a control port. The first switching device 601 and the first unidirectional device 602 cooperate with the first capacitor C1 and the first coil L1, and control whether to wirelessly charge the corresponding terminal device based on the on / off state of the first switching device 601.

[0082] It should be understood that before the wireless charging circuit performs wireless charging, the terminal device corresponding to the electronic device must first establish a wireless connection with the electronic device including the wireless charging circuit. For example, before the tablet computer wirelessly charges the stylus 20, the tablet computer must first establish a wireless connection with the stylus 20. Or, before the tablet computer wirelessly charges the wireless keyboard 30, the tablet computer must first establish a wireless connection with the wireless keyboard 30.

[0083] For example, when the first switching device 601 is in the ON state, the first capacitor C1 and the first coil L1 form a resonant circuit. Alternating current passes through the first switching device 601 or the first unidirectional device 602, and is converted into magnetic field energy by the first capacitor C1 and the first coil L1, which is then radiated into space, thereby wirelessly charging the corresponding terminal device (e.g., stylus 20 or wireless keyboard 30). When the first switching device 601 is in the OFF state, the alternating current charges the first capacitor C1 to a preset voltage through the first unidirectional device 602, and stops radiating electromagnetic energy into space, thus stopping the wireless charging of the corresponding terminal device.

[0084] Figure 7 is a circuit diagram of another wireless charging circuit provided in this application embodiment.

[0085] As shown in Figure 7, in one embodiment of this application, the wireless charging circuit 600 includes a first PMOS transistor Q1, a first capacitor C1, and a first coil L1. The first PMOS transistor Q1 includes a first transistor structure A1 and a first parasitic diode D1. The gate of the first transistor structure A1 is a control port. The drain of the first transistor structure A1 is connected to the first power supply terminal of the AC power supply and the positive terminal of the first parasitic diode D1. The source of the first transistor structure A1 is connected to the first plate of the first capacitor C1 and the negative terminal of the first parasitic diode D1. The second plate of the first capacitor C1 is connected to the first end of the first coil L1, and the second end of the first coil L1 is connected to the second power supply terminal of the AC power supply. The first PMOS transistor Q1 (i.e., the first transistor structure A1 and the first parasitic diode D1) works in conjunction with the first capacitor C1 and the first coil L1 to control whether to wirelessly charge the corresponding terminal device based on the on / off state of the first transistor structure A1.

[0086] For example, when the gate of the first transistor structure A1 receives a low-level signal and the AC power supply is in its positive half-cycle, the gate-source voltage Vsg of the first transistor structure A1 is greater than the conduction threshold, and the AC power flows from the first power supply terminal to the second power supply terminal of the AC power supply through the first parasitic diode D1. When the gate of the first transistor structure A1 receives a low-level signal and the AC power supply is in its negative half-cycle, the gate-source voltage Vsg of the first transistor structure A1 is greater than the conduction threshold, the source and drain of the first transistor structure A1 are turned on, and the AC power flows from the second power supply terminal to the first power supply terminal of the AC power supply through the first transistor structure A1. Therefore, during the process of the gate of the first transistor structure A1 receiving a low-level signal, the first capacitor C1 and the first coil L1 form a resonant circuit. The AC power supply passes through the first transistor structure A1 or the first parasitic diode D1, and is converted into magnetic field energy and radiated into space through the first capacitor C1 and the first coil L1, thereby wirelessly charging the corresponding terminal device (e.g., stylus 20 or wireless keyboard 30).

[0087] When the gate of the first transistor structure A1 receives a high-level signal or does not receive a signal, and the AC power supply is in its positive half-cycle, the AC power supply will charge the first capacitor C1 to a preset voltage through the first parasitic diode D1 when it is first powered on. When the gate of the first transistor structure A1 receives a high-level signal or does not receive a signal, and the AC power supply is in its negative half-cycle, due to the unidirectional conduction characteristic of the body diode of the first parasitic diode D1, the first parasitic diode D1 is reverse-biased and cut off. Therefore, due to the DC blocking and AC passing characteristic of the first capacitor C1, the wireless charging circuit 600 cannot form a wireless charging path, cannot radiate electromagnetic energy into space, and stops wirelessly charging the corresponding terminal device.

[0088] It should be understood that in some other embodiments, the first switching device 601 may also be an electronic device such as a thyristor, transistor, or insulated gate bipolar transistor (IGBT).

[0089] It should be understood that the preset voltage is the maximum voltage of the first capacitor C1.

[0090] Figure 8 is a circuit diagram of another wireless charging circuit provided in this application embodiment.

[0091] As shown in Figure 8, in one embodiment provided in this application, the wireless charging circuit 600 includes a first switching device 601, a first unidirectional device 602, a first capacitor C1, a first coil L1, and a second switching device 603. The first switching device 601 has three terminals. The first terminal of the first switching device 601 is connected to the first power terminal of the AC power supply and the first terminal of the first unidirectional device 602, and is used to input AC power when the first power terminal of the AC power supply outputs AC power. The second terminal of the first switching device 601 is connected to the first plate of the first capacitor C1 and the second terminal of the first unidirectional device 602. The second plate of the first capacitor C1 is connected to the first terminal of the first coil L1. The second terminal of the first coil L1 is connected to the second power terminal of the AC power supply, and is used to output AC power. The third terminal of the first switching device 601 is connected to the first terminal of the second switching device 603. The second terminal of the second switching device 603 is grounded, and the third terminal of the second switching device 603 is a control port. The second switching device 603 is used to receive control signals and turn on or off according to the control signals, thereby controlling the on and off of the first switching device 601 through the on and off of the second switching device 603. The first switching device 601 and the first unidirectional device 602 are used to cooperate with the first capacitor C1 and the first coil L1, and control whether to wirelessly charge the corresponding terminal device according to the on and off of the first switching device 601.

[0092] For example, when the second switching device 603 is in the ON state, the second switching device 603 is also in the ON state. At this time, the first capacitor C1 and the first coil L1 form a resonant circuit. The AC current passes through the first switching device 601 or the first unidirectional device 602, and is converted into magnetic field energy through the first capacitor C1 and the first coil L1 and radiated into space, thereby wirelessly charging the corresponding terminal device (e.g., stylus 20 or wireless keyboard 30). When the second switching device 603 is in the OFF state, the second switching device 603 is also in the OFF state. At this time, the AC current charges the first capacitor C1 to a preset voltage through the first unidirectional device 602, and stops radiating electromagnetic energy into space, thereby stopping the wireless charging of the corresponding terminal device.

[0093] Figure 9 is a circuit diagram of another wireless charging circuit provided in this application embodiment.

[0094] As shown in Figure 9, in one embodiment of this application, the wireless charging circuit 600 includes a first PMOS transistor Q1, a first capacitor C1, a first coil L1, and a second NMOS transistor Q2. The first PMOS transistor Q1 includes a first transistor structure A1 and a first parasitic diode D1. The drain of the first transistor structure A1 is connected to the first power supply terminal of the AC power supply and the positive terminal of the first parasitic diode D1. The source of the first transistor structure A1 is connected to the first plate of the first capacitor C1 and the negative terminal of the first parasitic diode D1. The second plate of the first capacitor C1 is connected to the first end of the first coil L1, and the second end of the first coil L1 is connected to the second power supply terminal of the AC power supply. The gate of the second NMOS transistor Q2 is a control port. The drain of the second NMOS transistor Q2 is connected to the first end of the first PMOS transistor Q1, and the source of the second NMOS transistor Q2 is grounded. The second NMOS transistor Q2 receives control signals and turns on or off according to the control signals, thereby controlling the on and off of the first PMOS transistor Q1 through the on and off states of the second NMOS transistor Q2. The first PMOS transistor Q1 (i.e., the first transistor structure A1 and the first parasitic diode D1) is used in conjunction with the first capacitor C1 and the first coil L1, and controls whether to wirelessly charge the corresponding terminal device according to the conduction and disconnection of the first transistor structure A1.

[0095] For example, when the gate of the second NMOS transistor Q2 receives a high-level signal, the second NMOS transistor Q2 is turned on, thereby causing the gate of the first transistor structure A1 to receive a low-level signal and the first transistor structure A1 to be turned on.

[0096] When the gate of the first transistor structure A1 receives a low-level signal and the AC power supply is in its positive half-cycle, the gate-source voltage Vsg of the first transistor structure A1 is greater than the conduction threshold. The AC power flows from the first power supply terminal to the second power supply terminal through the first parasitic diode D1. When the gate of the first transistor structure A1 receives a low-level signal and the AC power supply is in its negative half-cycle, the gate-source voltage Vsg of the first transistor structure A1 is greater than the conduction threshold. The source and drain of the first transistor structure A1 are turned on, and the AC power flows from the second power supply terminal to the first power supply terminal through the first transistor structure A1. Therefore, during the process of the gate of the first transistor structure A1 receiving a low-level signal, the first capacitor C1 and the first coil L1 form a resonant circuit. The AC power from the AC power supply passes through the first transistor structure A1 or the first parasitic diode D1, and is converted into magnetic field energy and radiated into space through the first capacitor C1 and the first coil L1, thereby wirelessly charging the corresponding terminal device (e.g., stylus 20 or wireless keyboard 30).

[0097] When the gate of the second NMOS transistor Q2 receives a low-level signal, Q2 is turned off, thereby pulling the gate of the first transistor structure A1 high. When the gate of the first transistor structure A1 receives a high-level signal or does not receive a signal, and the AC power supply is in its positive half-cycle, the AC power supply will charge the first capacitor C1 to a preset voltage through the first parasitic diode D1 when it is first powered on. When the gate of the first transistor structure A1 receives a high-level signal or does not receive a signal, and the AC power supply is in its negative half-cycle, due to the unidirectional conduction characteristic of the first parasitic diode D1, it is reverse-biased and cut off. Therefore, due to the DC-blocking and AC-passing characteristic of the first capacitor C1, the wireless charging circuit 600 cannot form a wireless charging path, thus stopping the wireless charging circuit 600 from radiating electromagnetic energy into space and stopping wireless charging of the corresponding terminal device. It should be understood that in some other embodiments, the first switching device 601 may also be an electronic device such as a thyristor, transistor, or insulated gate bipolar transistor (IGBT).

[0098] It should be understood that the preset voltage is the maximum voltage of the first capacitor C1.

[0099] Figure 10 is a circuit diagram of another wireless charging circuit provided in this application embodiment.

[0100] As shown in Figure 10, in one embodiment provided in this application, the wireless charging circuit 600 includes a first switching device 601, a first unidirectional device 602, a first capacitor C1, and a first coil L1. It should be noted that the difference between this embodiment and the wireless charging circuit shown in Figure 6 is that the wireless charging circuit further includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 and the first end of the second resistor R2 are both connected to the control terminal of the first switching device 601. The second end of the first resistor R1 is the control port, and the second end of the second resistor R2 is connected to the second end of the first switching device 601.

[0101] In this embodiment, the first resistor R1 and the second resistor R2 form a voltage divider resistor, thereby adjusting the voltage between the control terminal and the second terminal of the first switching device 601 according to the resistance ratio of the first resistor R1 and the second resistor R2.

[0102] It should be understood that, in the embodiments of this application, other specific implementations of the wireless charging circuit 600 can be referred to the above description of FIG6, and will not be repeated here.

[0103] Figure 11 is a circuit diagram of another wireless charging circuit provided in this application embodiment.

[0104] As shown in Figure 11, in one embodiment provided in this application, the wireless charging circuit 600 includes a first switching device 601, a first unidirectional device 602, a first capacitor C1, and a first coil L1. It should be noted that the difference between this embodiment and the wireless charging circuit shown in Figure 6 is that the wireless charging circuit further includes a second capacitor C2. The first end of the second capacitor C2 is connected to the control terminal of the first switching device 601, and the second end of the second capacitor C2 is connected to the second end of the first switching device 601.

[0105] In this embodiment, the second capacitor C2 serves as a voltage regulator capacitor, used to stabilize the voltage between the control terminal and the second terminal of the first switching device 601.

[0106] It should be understood that, in the embodiments of this application, other specific implementations of the wireless charging circuit 600 can be referred to the above description of FIG6, and will not be repeated here.

[0107] Figure 12 is a schematic diagram of the structure of another wireless charging module provided in this application embodiment.

[0108] As shown in Figure 12, in one embodiment provided in this application, the wireless charging module 200 includes a control module 701 and multiple wireless charging circuits. The wireless charging circuits shown in the figure include a first wireless charging circuit 600A and a second wireless charging circuit 600B. Both the first wireless charging circuit 600A and the second wireless charging circuit 600B are the wireless charging circuits 600 shown in Figures 6 to 11. The control module 701 includes a power input terminal, a power output terminal, and a control terminal. The power output terminal of the control module 701 is connected to the AC power input terminals of the multiple wireless charging circuits 600, and the power input terminals of the control module 701 are connected to the AC power output terminals of the multiple wireless charging circuits 600. The control terminal of the control module 701 is connected to the control terminals of the multiple wireless charging circuits 600. The control module 701 is used to control one of the multiple wireless charging circuits 600 to be turned on, while the other wireless charging circuits 600 are turned off. The wireless charging circuits 600 are used to wirelessly charge wirelessly connected terminal devices.

[0109] For example, when the wireless charging circuit 600 receives the turn-on signal from the control module 701, the wireless charging circuit 600 turns on and radiates electromagnetic energy into space, thereby wirelessly charging the corresponding terminal device. When the wireless charging circuit 600 receives the turn-off signal from the control module 701, the wireless charging circuit 600 turns off, stops radiating electromagnetic energy into space, and thus stops wirelessly charging the corresponding terminal device.

[0110] Figure 13 is a circuit diagram of another wireless charging module provided in this application embodiment.

[0111] As shown in Figure 13, in one embodiment provided in this application, the wireless charging module 200 includes a control module 701, a stylus charging circuit 2021, and a wireless keyboard charging circuit 2022. The control module 701 includes a power input terminal, a power output terminal, and a control terminal. The power output terminal of the control module 701 is connected to the first power terminals of the AC power supplies of the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022, respectively. The power input terminal of the control module 701 is connected to the second power terminals of the AC power supplies of the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022, respectively. The control terminal of the control module 701 is connected to the control terminals of multiple stylus charging circuits 2021 and wireless keyboard charging circuits 2022. The control module 701 is used to control one of the stylus charging circuits 2021 and the wireless keyboard charging circuit 2022 to be turned on and the other to be turned off. The stylus charging circuit 2021 is used to wirelessly charge the stylus when it is turned on and to stop wirelessly charging the stylus when it is turned off. The wireless keyboard charging circuit 2022 is used to wirelessly charge the wireless keyboard when it is in the on state and to stop wirelessly charging the wireless keyboard when it is in the off state.

[0112] It should be understood that, in the embodiments of this application, the wireless charging module 200 may include not only the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022, but may also include other similar wireless charging circuits, such as a watch wireless charging circuit or an earphone wireless charging circuit.

[0113] For example, the stylus charging circuit 2021 includes a first PMOS transistor Q1, a first capacitor C1, a first coil L1, a second NMOS transistor Q2, a first resistor R1, a second resistor R2, and a second capacitor C2. The first PMOS transistor Q1 includes a first transistor structure A1 and a first parasitic diode D1. The gate of the first transistor structure A1 is connected to the drain of the second NMOS transistor Q2 through the first resistor R1. The drain of the first transistor structure A1 is connected to the power output terminal of the control module 701 and the positive terminal of the first parasitic diode D1. The source of the first transistor structure A1 is connected to the negative terminal of the first parasitic diode D1 and the first plate of the first capacitor C1. The second plate of the first capacitor C1 is connected to the first end of the first coil L1. The second end of the first coil L1 is connected to the power input terminal of the control module 701. The gate of the second NMOS transistor Q2 is connected to the control terminal of the control module 701, and the source of the second NMOS transistor Q2 is grounded. The second resistor R2 and the second capacitor C2 are both connected between the gate and source of the first transistor structure A1.

[0114] When the stylus 20 approaches the electronic device 10, and the control module 701 detects that the stylus 20 is within a preset range of the electronic device 10, the control module 701 outputs a wireless charging enable signal and sends it to the gate of the second NMOS transistor Q2 in the stylus charging circuit 2021. When the gate of the second NMOS transistor Q2 receives the stylus enable signal (i.e., a high-level signal), the second NMOS transistor Q2 turns on, thereby pulling down the gate of the first transistor structure A1. When the gate of the first transistor structure A1 receives a low-level signal, the first transistor structure A1 turns on, thereby radiating electromagnetic energy to the stylus 20 through the resonant circuit formed by the first transistor structure A1 or the first parasitic diode D1, the first capacitor C1, and the first inductor L1, thus enabling the stylus charging circuit 2021 to wirelessly charge the stylus 20. The first resistor R1 and the second resistor R2 form a voltage divider circuit to adjust the voltage between the gate and source of the first transistor structure A1. The second capacitor C2 is used to regulate the voltage between the gate and source of the first transistor structure A1.

[0115] When the stylus 20 moves away from the electronic device 10, and the control module 701 detects that the stylus 20 is outside a preset range of the electronic device 10, the control module 701 outputs a stylus wireless charging disconnect signal and sends it to the gate of the second NMOS transistor Q2 in the stylus charging circuit 2021. When the gate of the second NMOS transistor Q2 receives the stylus disconnect signal (i.e., a low-level signal), the second NMOS transistor Q2 turns off, thereby pulling up the gate of the first transistor structure A1. When the gate of the first transistor structure A1 receives a high-level signal, the first transistor structure A1 turns off, thereby stopping the stylus charging circuit 2021 from wirelessly charging the stylus 20.

[0116] For example, the wireless keyboard charging circuit 2022 includes a third PMOS transistor Q3, a third capacitor C3, a second coil L2, a fourth NMOS transistor Q4, a third resistor R3, a fourth resistor R4, and a fourth capacitor C4. The third PMOS transistor Q3 includes a third transistor structure A3 and a second parasitic diode D2. The gate of the third transistor structure A3 is connected to the drain of the fourth NMOS transistor Q4 through the third resistor R3. The drain of the third transistor structure A3 is connected to the power output terminal of the control module 701 and the positive terminal of the second parasitic diode D2. The source of the third transistor structure A3 is connected to the negative terminal of the second parasitic diode D2 and the first plate of the third capacitor C3. The second plate of the third capacitor C3 is connected to the first end of the second coil L2. The second end of the second coil L2 is connected to the power input terminal of the control module 701. The gate of the fourth NMOS transistor Q4 is connected to the control terminal of the control module 701, and the source of the fourth NMOS transistor Q4 is grounded. The fourth resistor R4 and the fourth capacitor C4 are both connected between the gate and source of the third transistor structure A3.

[0117] When the wireless keyboard 30 approaches the electronic device 10, and the control module 701 detects that the wireless keyboard 30 is within a preset range of the electronic device 10, the control module 701 outputs a wireless charging enable signal and sends it to the gate of the fourth NMOS transistor Q4 of the wireless keyboard 30. When the gate of the fourth NMOS transistor Q4 receives the enable signal (i.e., a high-level signal) from the wireless keyboard 30, the fourth NMOS transistor Q4 turns on, thereby pulling down the gate of the third transistor structure A3. When the gate of the third transistor structure A3 receives a low-level signal, the third transistor structure A3 turns on, thereby radiating electromagnetic energy to the wireless keyboard 30 through the resonant circuit formed by the third transistor structure A3 or the second parasitic diode D2, the third capacitor C3, and the second inductor L2, thus enabling the wireless keyboard charging circuit 2022 to wirelessly charge the wireless keyboard 30. The third resistor R3 and the fourth resistor R4 form a voltage divider circuit to adjust the voltage connected between the gate and source of the third transistor structure A3, and the fourth capacitor C4 is used to regulate the voltage connected between the gate and source of the third transistor structure A3.

[0118] When the wireless keyboard 30 moves away from the electronic device 10, and the control module 701 detects that the wireless keyboard 30 is outside a preset range of the electronic device 10, the control module 701 outputs a wireless keyboard wireless charging disconnect signal and sends it to the gate of the fourth NMOS transistor Q4 in the wireless keyboard charging circuit 2022. When the gate of the fourth NMOS transistor Q4 receives the wireless keyboard disconnect signal (i.e., a low-level signal), the fourth NMOS transistor Q4 turns off, thereby pulling up the gate of the third transistor structure A3. When the gate of the third transistor structure A3 receives a high-level signal, the third transistor structure A3 turns off, thereby stopping the wireless keyboard charging circuit 2022 from wirelessly charging the wireless keyboard 30.

[0119] The circuit diagram of the wireless charging module provided in this application embodiment is simulated and tested below, using both simulated and measured waveforms.

[0120] Figure 14 is a simulation waveform diagram of a wireless charging module provided in an embodiment of this application.

[0121] For example, in one embodiment provided in this application, simulation of the circuit diagram of the wireless charging module shown in Figure 13 shows that: the power output terminal of the control module 701 outputs a stable square wave of 147KHz. After running for 0.2ms, the control module 701 outputs a stylus turn-on signal (i.e., a high-level signal) to the second NMOS transistor Q2. The second NMOS transistor Q2 enters the turn-on state according to the stylus turn-on signal, thereby pulling down the gate voltage of the first PMOS transistor Q1. When the first PMOS transistor Q1 receives the low-level signal, the first PMOS transistor Q1 turns on, thereby causing the first capacitor C1 and the first coil L1 to convert the square wave into electromagnetic energy and radiate it into space, thereby enabling the stylus charging circuit 2021 to wirelessly charge the stylus 20. It should be noted that at this time, the fourth NMOS transistor Q4 is not driven, and the third PMOS transistor Q3 and the fourth NMOS transistor Q4 remain in the off state, thereby preventing the wireless keyboard charging circuit 2022 from wirelessly charging the wireless keyboard 30.

[0122] As shown in Figure 14, VIN is a stable square wave of 147KHz, Q2-G is the gate signal of the second NMOS transistor Q2 in the stylus path, Q3-G is the gate signal of the third PMOS transistor Q3 in the wireless keyboard path, VC1 is the voltage across the resonant capacitor (i.e., the first capacitor C1) in the stylus path, VC3 is the voltage across the resonant capacitor (i.e., the third capacitor C3) in the wireless keyboard path, Ipen is the current in the stylus path, and Ikeyboard is the current in the wireless keyboard path.

[0123] As can be seen from the simulation waveform, during the period from the start to 0.2ms, a stable 147kHz square wave is stably output from the power output terminal of the control module 701 to the stylus charging circuit 2021 and the wireless keyboard charging circuit 2022. When the stylus charging circuit 2021 receives the stable 147kHz square wave, it charges the resonant capacitor (i.e., the first capacitor C1) through the body diode in the first PMOS transistor Q1. After the first capacitor C1 is fully charged, the voltage VC1 across the first capacitor C1 remains at the charged voltage, the first PMOS transistor Q1 is turned off, and the current Ipen flowing through the stylus path of the first PMOS transistor Q1 is 0. At this time, there is no driving voltage at the gate of the second NMOS transistor Q2, and the driving signal Q2-G of the stylus path is a low-level signal.

[0124] When the wireless keyboard charging circuit 2022 receives a stable 147kHz square wave, the 147kHz stable square wave charges the resonant capacitor (i.e., the third capacitor C3) through the body diode inside the third PMOS transistor Q3. After the third capacitor C3 is fully charged, the voltage VC3 across the third capacitor C3 remains at the charged voltage, the third PMOS transistor Q3 is turned off, and the current Ikeyboard flowing through the wireless keyboard path of the third PMOS transistor Q3 is 0. At this time, there is no driving voltage at the gate of the third PMOS transistor Q3, and the driving signal Q3-G of the wireless keyboard path is a high-level signal.

[0125] 0.2ms later, the control module 701 inputs a high-level signal to the gate of the second NMOS transistor Q2, i.e., Q2-G is high, thereby turning on the second NMOS transistor Q2, pulling down the gate voltage of the first PMOS transistor Q1, thus turning on the first PMOS transistor Q1, and consequently turning on the stylus charging circuit 2021 to wirelessly charge the stylus 20. At this time, the current Ipen in the stylus path begins to show waveform changes, and the voltage VC1 across the resonant capacitor (i.e., the first capacitor C1) also begins to show voltage changes.

[0126] It should be noted that during the process of the stylus charging circuit 2021 being turned on and wirelessly charging the stylus 20, the wireless keyboard charging circuit 2022 does not receive an enable signal, so the wireless keyboard path remains disconnected. The current Ikeyboard in the wireless keyboard path remains 0, the drive signal Q3-G in the wireless keyboard path remains high, and the voltage VC3 across the resonant capacitor (i.e., the third capacitor C3) remains stable due to the lack of current discharge, maintaining its previous voltage value. Therefore, based on the above simulation waveforms, it can be seen that the wireless charging circuit 600 provided in this embodiment meets the expected design and can realize the on and off of the wireless charging path.

[0127] Figure 15 is a measured waveform diagram of a wireless charging module provided in an embodiment of this application.

[0128] As shown in Figure 15, by way of example, in one embodiment provided in this application, the actual verification can be performed according to the circuit diagram of the wireless charging module shown in Figure 13. In the wireless keyboard charging circuit 2022, the gate signal of the third PMOS transistor Q3 is MOS-G-Keyboard, and the path current of the wireless keyboard charging circuit 2022 is I-MOS-S-to-C-Keyboard. In the stylus charging circuit 2021, the gate signal of the first PMOS transistor Q1 is MOS-G-Pen, and the path current of the stylus charging circuit 2021 is I-MOS-S-to-C-Pen.

[0129] When the wireless charging module 200 wirelessly charges the stylus 20 using the stylus charging circuit 2021, the wireless keyboard charging circuit 2022 is in the off state. As shown in Figure 15, when the gate of the first PMOS transistor Q1 in the stylus charging circuit 2021 receives a drive signal, the gate of the first PMOS transistor Q1 is pulled low, thus turning on the first PMOS transistor Q1. Alternating current flows through the wireless charging path of the stylus, allowing the stylus charging circuit 2021 to wirelessly charge the stylus 20 normally. Simultaneously, since the gate of the third PMOS transistor Q3 in the wireless keyboard charging circuit 2022 does not receive a drive signal, the gate of the third PMOS transistor Q3 is at a high level, and the third PMOS transistor Q3 is in the off state.

[0130] It should be noted that since the third PMOS transistor Q3 is in the off state and no current flows through it, the voltage on the right plate of the resonant capacitor (i.e., the third capacitor C3) in the wireless keyboard charging circuit 2022 is equal to the power input voltage of the control module 701, i.e., V. 回流 However, at this time, the stylus charging circuit 2021 is wirelessly charging the stylus 20, therefore, the voltage V at the power input terminal of the control module 701 is [not specified]. 回流 It is a periodically changing square wave. Meanwhile, during the first charging of the resonant capacitor (i.e., the third capacitor C3) of the wireless keyboard charging circuit 2022, the voltage across the third capacitor C3 remains stable without a discharge path, i.e., V. 回流 Since the voltage across a capacitor cannot change abruptly, the voltage across the left plate of the third capacitor C3 is equal to V. 回流 Therefore, there is no voltage difference between the gate and source Vsg of the third PMOS transistor Q3, so it will not conduct and will exhibit a periodically changing waveform. For example, the waveform of the third PMOS transistor Q3 can be a square wave that periodically changes in the range of 5.3-10.6V.

[0131] Furthermore, in this embodiment, since the wireless charging path can be turned on and off using only a switching device and a capacitor, the number of electronic components used in the wireless charging circuit is effectively reduced, thus lowering the cost and size of the wireless charging circuit. It should be noted that when the wireless charging module 200 includes at least two wireless charging circuits, the wireless charging module also includes a first packaging structure and a second packaging structure. One of the first switching devices in the two wireless charging circuits is encapsulated within the first packaging structure, and the other of the first switching devices in the two wireless charging circuits is encapsulated within the second packaging structure. Alternatively, the wireless charging module also includes a third packaging structure, in which both first switching devices in the two wireless charging circuits are encapsulated within the third packaging structure. That is, the first switching device in each wireless charging circuit can either be individually packaged and connected as an independent device in the wireless charging circuit, or two first switching devices can be packaged together and connected to their respective wireless charging circuits. Table 1 below shows a cost comparison table for implementing the wireless charging path using two PMOS transistors in Figure 5 and one PMOS transistor in Figure 13, where X1 is the cost of a single PMOS transistor and X2 is the cost of a dual PMOS transistor.

[0132] Table 1 Cost Comparison Table

[0133] As can be seen from Table 1 above, when the wireless charging module 200 includes two wireless charging circuits, the single PMOS transistor solution provided in this application embodiment can save the cost of two separate PMOS transistors or one dual PMOS transistor, which is more suitable for the development trend of miniaturization and low cost of electronic devices.

[0134] The foregoing description, in conjunction with Figures 1 to 15, outlines the structural schematics, circuit diagrams, waveform diagrams, and applicable scenarios of several embodiments provided in this application. The following description, in conjunction with Figure 16, details the hardware system and chip system of the electronic device to which this application applies. It should be understood that the hardware system and chip system in the embodiments of this application can execute the various structural schematics or circuit diagrams of the aforementioned embodiments of this application; that is, the specific working processes of the various products described below can be referenced to the corresponding working processes in the foregoing embodiments.

[0135] Figure 16 shows a hardware system of a terminal device provided in an embodiment of this application.

[0136] As shown in Figure 16, by way of example, in this embodiment of the application, the electronic device 10 can be a tablet computer as shown in Figures 1 and 2, or it can be a mobile phone, smart screen, wearable electronic device, in-vehicle electronic device, augmented reality device, virtual reality (VR) device, laptop computer, ultra-mobile personal computer (UMPC), netbook, personal digital assistant (PDA), or other terminal device with wireless charging function. This embodiment of the application does not limit the specific type of the electronic device 10. The electronic device 10 provided in this embodiment of the application can realize the conduction and disconnection of the wireless charging path through a switching device and a capacitor, thereby effectively reducing the number of electronic components used in the wireless charging circuit, reducing the cost of the wireless charging circuit, and shrinking the size of the wireless charging circuit. Therefore, it is more suitable for the development trend of miniaturization and low cost of electronic devices.

[0137] Electronic device 10 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 300, a first antenna 1, a second antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headphone jack 170D, a sensor module 180, buttons 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a magnetic sensor 180A, which is the Hall sensor mentioned above.

[0138] It should be noted that the structure shown in this hardware system does not constitute a specific limitation on the electronic device. In other embodiments of this application, the electronic device may include more or fewer components than those shown in the hardware system, or the electronic device may include a combination of certain components shown in the hardware system, or the electronic device may include sub-components of certain components shown in the hardware system. The components shown in the hardware system may be implemented in hardware, software, or a combination of software and hardware.

[0139] Processor 110 may include one or more processing units. For example, processor 110 may include at least one of the following processing units: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, video codec, digital signal processor (DSP), baseband processor, and neural network processing unit (NPU). These different processing units may be independent devices or integrated devices. The controller can generate operation control signals based on instruction opcodes and timing signals to control instruction fetching and execution.

[0140] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0141] The connection relationships between the modules shown in this hardware system are merely illustrative and do not constitute a limitation on the connection relationships between the modules of the electronic device. Optionally, the modules of the electronic device may also adopt a combination of various connection methods described in the above embodiments.

[0142] The charging management module 140 is used to receive power from the charger or transmit power to other electronic devices. While charging the battery 300, the charging management module 140 can also power electronic devices via the power management module 141, and can wirelessly charge other electronic devices near the electronic device 10 via its internal wireless charging module. The power management module 141 is used to connect the battery 300, the charging management module 140, and the processor 110. The power management module 141 receives input from the battery 300 and / or the charging management module 140, and powers the processor 110, internal memory 121, display screen 194, camera 193, and wireless communication module 160, etc. The power management module 141 can also be used to monitor parameters such as battery capacity, battery cycle count, and battery health status (e.g., leakage current, impedance). Optionally, the power management module 141 can be located in the processor 110, or the power management module 141 and the charging management module 140 can be located in the same device.

[0143] For example, in this embodiment of the application, the electronic device 10 supports the magnetic attraction of a stylus 20 or a wireless keyboard 30 to a preset area of ​​the electronic device 10. When the magnetic sensor 180A detects that the stylus 20 or the wireless keyboard 30 is attracted to the electronic device 10, the electronic device can determine the presence status of the stylus 20 or the wireless keyboard 30 through the processor 110. When the stylus 20 or the wireless keyboard 30 is in the presence status, the processor 110 controls the charging management module 140 (e.g., a charging chip) to wirelessly charge the stylus 20 or the wireless keyboard 30. At the same time, the processor 110 controls the charging management module 140 to continue or stop charging the stylus 20 or the wireless keyboard 30 based on whether the magnetic sensor 180A reports an event of the stylus 20 or the wireless keyboard 30 being removed and whether the charging management module 140 receives an interrupt event indicating that charging has stopped.

[0144] It should be understood that electronic device 10 can only wirelessly charge one of the terminal devices, stylus 20 or wireless keyboard 30, at a time. That is, when electronic device 10 is wirelessly charging stylus 20, it only charges stylus 20 and does not wirelessly charge wireless keyboard 30 or other terminal devices. Similarly, when electronic device 10 is wirelessly charging wireless keyboard 30, it only charges wireless keyboard 30 and does not wirelessly charge stylus 20 or other terminal devices.

[0145] The wireless communication function of the electronic device can be implemented through devices such as antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor, and baseband processor. Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the electronic device can be used to cover one or more communication frequency bands. Different antennas can also be reused to improve antenna utilization.

[0146] The mobile communication module 150 can provide a wireless communication solution for use in electronic devices, such as at least one of the following: a second-generation (2G) mobile communication solution, a third-generation (3G) mobile communication solution, a fourth-generation (5G) mobile communication solution, or a fifth-generation (5G) mobile communication solution.

[0147] The modem processor may include a modulator and a demodulator. The modulator modulates a low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates a received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through audio devices (e.g., speaker 170A, receiver 170B) or displays images or videos through the display screen 194. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0148] Similar to the mobile communication module 150, the wireless communication module 160 can also provide wireless communication solutions for use in electronic devices, such as at least one of the following: wireless local area networks (WLAN), Bluetooth (BT), Bluetooth Low Energy (BLE), ultra-wideband (UWB), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR) technology, etc.

[0149] In some embodiments, the antenna 1 of the electronic device is coupled to the mobile communication module 150, and the antenna 2 of the electronic device is coupled to the wireless communication module 160, enabling the electronic device to communicate with the network and other electronic devices via wireless communication technology.

[0150] The external storage interface 120 can be used to connect an external memory card, such as a secure digital (SD) card, to expand the storage capacity of the electronic device. The external memory card communicates with the processor 110 through the external storage interface 120 to perform data storage functions. For example, music, video, and other files can be saved on the external memory card.

[0151] Internal memory 121 can be used to store computer executable program code, which includes instructions. Internal memory 121 may include a program storage area and a data storage area.

[0152] Button 190 includes a power button and volume buttons. Button 190 can be a mechanical button or a touch button. The electronic device can receive button input signals and realize functions related to the button input signals.

[0153] Exemplary embodiments of this application also provide an electronic device, including the wireless charging circuit or wireless charging module as described above. The electronic device further includes a battery for storing electrical energy. The wireless charging circuit or wireless charging module converts the battery's electrical energy into electromagnetic energy and radiates it into space, thereby enabling wireless charging of other terminal devices (such as styluses or wireless keyboards). The wireless charging module includes the wireless charging circuit described above. It should be understood that the wireless charging circuit of the electronic device provided in this application embodiment can realize the conduction and cutoff of the wireless charging path using only a switching device and a capacitor, thereby effectively reducing the number of electronic components used in the wireless charging circuit, reducing the cost of the wireless charging circuit, and shrinking the size of the wireless charging circuit. Therefore, it is more suitable for the development trend of miniaturization and low cost of electronic devices.

[0154] It should be understood that the above is only an example of the structure of electronic device 10. Electronic device 10 may also include other subsystems or devices, which can be set and modified as needed. This application embodiment does not impose any restrictions on this.

[0155] The beneficial effects that the electronic device provided in the above-described embodiments of this application can achieve can be referred to the beneficial effects corresponding to the modules provided above, and will not be repeated here.

[0156] It should be understood that the above description is merely to help those skilled in the art better understand the embodiments of this application, and is not intended to limit the scope of the embodiments of this application. Based on the examples given above, those skilled in the art can obviously make various equivalent modifications or changes. For example, some steps in the various embodiments of the above detection method may be unnecessary, or new steps may be added. Alternatively, any combination of two or more of the above embodiments may be used. Such modifications, changes, or combinations also fall within the scope of the embodiments of this application. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0157] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0158] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0159] It should also be understood that the above description of the embodiments of this application focuses on highlighting the differences between the various embodiments. Any similarities or differences not mentioned can be referred to each other. For the sake of brevity, they will not be repeated here.

[0160] It should also be understood that, in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0161] It should also be understood that in the embodiments of this application, "pre-setting" or "pre-defining" can be achieved by pre-saving the corresponding code, table or other means that can be used to indicate relevant information in the device (e.g., including electronic devices), and this application does not limit the specific implementation method.

[0162] It should also be understood that the methods, situations, categories, and classifications of embodiments in this application are for the convenience of description only and should not constitute a special limitation. Various methods, categories, situations, and features in embodiments can be combined without contradiction.

[0163] It should also be understood that, in the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0164] Finally, it should be noted that the above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims. In conclusion, the above descriptions are merely preferred embodiments of the technical solutions of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A wireless charging circuit, characterized in that, It includes a first switching device, a first unidirectional device, a first capacitor, and a first coil. The first end of the first switching device is connected to the first power supply terminal of the AC power supply and the first end of the first unidirectional device. The second end of the first switching device is connected to the first plate of the first capacitor and the second end of the first unidirectional device. The second plate of the first capacitor is connected to the first end of the first coil. The second end of the first coil is connected to the second power supply terminal of the AC power supply. When the first switching device is in the ON state, the AC power output from the AC power source passes through the first switching device or the first unidirectional device, and radiates electromagnetic energy into space through the first capacitor and the first coil; when the first switching device is in the OFF state, the AC power source charges the first capacitor to a preset voltage through the first unidirectional device, and stops radiating electromagnetic energy into space.

2. The wireless charging circuit as described in claim 1, characterized in that, The wireless charging circuit includes a first PMOSFET, which includes a transistor structure and a parasitic diode. The first switching device is the transistor structure, and the first unidirectional device is the parasitic diode.

3. The wireless charging circuit as described in claim 1, characterized in that, The wireless charging circuit further includes a second switching device, the first end of which is connected to the control terminal of the first switching device, and the second end of which is grounded; when the second switching device is in the conducting state, the first switching device is also in the conducting state.

4. The wireless charging circuit as described in claim 3, characterized in that, The second switching device includes a second NMOSFET, the drain of the second NMOSFET is connected to the control terminal of the first switching device, and the source of the second NMOSFET is grounded.

5. The wireless charging circuit as described in any one of claims 1-4, characterized in that, The wireless charging circuit further includes a first resistor and a second resistor. The first end of the first resistor and the first end of the second resistor are both connected to the control terminal of the first switching device, and the second end of the second resistor is connected to the second terminal of the first switching device.

6. The wireless charging circuit according to any one of claims 1-4, characterized in that, The wireless charging circuit further includes a second capacitor, the first end of which is connected to the control terminal of the first switching device, and the second end of which is connected to the second terminal of the first switching device.

7. A wireless charging module, characterized in that, The device includes a control module and a plurality of wireless charging circuits as described in any one of claims 1-6; the control module is connected to the plurality of wireless charging circuits respectively; the control module is used to control one of the plurality of wireless charging circuits to be turned on; when the wireless charging circuit is in the turned-on state, it is used to radiate electromagnetic energy into the space.

8. The wireless charging module as described in claim 7, characterized in that, The wireless charging circuit includes at least one of a stylus charging circuit and a wireless keyboard charging circuit, wherein only one of the stylus charging circuit and the wireless keyboard charging circuit is turned on at a time.

9. The wireless charging module as described in claim 7, characterized in that, The wireless charging module further includes a first packaging structure and a second packaging structure. One of the first switching devices in the two wireless charging circuits is encapsulated in the first packaging structure, and the other of the first switching devices in the two wireless charging circuits is encapsulated in the second packaging structure.

10. The wireless charging module as described in claim 7, characterized in that, The wireless charging module also includes a third packaging structure, in which the first switching devices in the two wireless charging circuits are encapsulated.

11. An electronic device, characterized in that, The electronic device includes a wireless charging circuit as described in any one of claims 1 to 6 or a wireless charging module as described in any one of claims 7 to 10, and further includes a battery; both the wireless charging circuit and the wireless charging module are used to convert the electrical energy of the battery into electromagnetic energy and radiate it into the space.

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