Wireless charging and discharging circuit, chip and electronic device

Abstract

This application relates to the field of electronic circuit technology, and in particular to a wireless charging and discharging circuit, chip, and electronic device. The wireless charging and discharging circuit includes: a charging receiving coil, a charging transmitting coil, a first resonant compensation circuit, a second resonant compensation circuit, a first isolating switch, a second isolating switch, a first bootstrap circuit, a second bootstrap circuit, and a charging control chip. The first end of the charging transmitting coil is connected to the first control pin of the charging control chip, and the first end of the charging receiving coil is also connected to the first control pin of the charging control chip. The wireless charging and discharging circuit provided in this application replaces the two wireless charging chips in related technologies with a structure consisting of a charging receiving coil, a charging transmitting coil, and a charging control chip, enabling wireless charging of electronic devices and reverse wireless charging of styluses, thus saving on hardware costs.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a wireless charging and discharging circuit, chip, and electronic device. Background Technology

[0002] With the development of electronic device technology, most electronic devices now possess wireless charging capabilities for convenient charging. For example, most tablets on the market are equipped with capacitive styluses for user interaction. Therefore, most tablets not only require an external wireless charging dock for wireless charging but also need to wirelessly charge the stylus via the tablet's reverse discharge. To achieve this, related technologies require two wireless charging chips: one to receive wireless power from the charging dock to charge the tablet's battery, and the other to receive reverse discharge from the battery to charge the stylus. However, requiring two wireless charging chips increases the hardware cost of the circuit. Summary of the Invention

[0003] This application provides a wireless charging and discharging circuit, chip, and electronic device to solve the technical problem that the wireless charging circuit of a tablet computer requires two wireless charging chips, resulting in high circuit hardware costs.

[0004] In a first aspect, this application provides a wireless charging and discharging circuit, which is used in an electronic device. The wireless charging and discharging circuit includes: a charging receiving coil, a charging transmitting coil, a first resonant compensation circuit, a second resonant compensation circuit, a first isolation switch, a second isolation switch, a first bootstrap circuit, a second bootstrap circuit, and a charging control chip. The first end of the charging transmitting coil is connected to the first control pin of the charging control chip; the second end of the charging transmitting coil is connected to the first end of the first resonant compensation circuit; the second end of the first resonant compensation circuit is connected to the first end of the first isolating switch; and the second end of the first isolating switch is connected to the second control pin of the charging control chip. The output end of the first bootstrap circuit is connected to the control end of the first isolating switch; and the first end of the first bootstrap circuit is connected to the first bootstrap capacitor pin on the charging control chip. The first bootstrap circuit is used to sample electrical energy to output a first on / off control signal. The first on / off control signal is used to control the conduction or deactivation of the first isolating switch, thereby controlling whether the charging transmitting coil is connected for operation. The first end of the charging receiving coil is connected to the first control pin of the charging control chip, the second end of the charging receiving coil is connected to the first end of the second resonant compensation circuit, the second end of the second resonant compensation circuit is connected to the first end of the second isolating switch, and the second end of the second isolating switch is connected to the second control pin of the charging control chip; the output end of the second bootstrap circuit is connected to the control end of the second isolating switch, and the first and second input ends of the second bootstrap circuit are respectively connected to the first and second ends of the charging receiving coil; the second bootstrap circuit is used to sample electrical energy to output a second on / off control signal, which is used to control the conduction or deactivation of the second isolating switch, thereby controlling whether the charging receiving coil is connected for operation.

[0005] In one possible design, the wireless charging and discharging circuit further includes at least one voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the voltage output pin of the charging control chip, and the output terminal of the voltage conversion circuit is connected to the charging terminal of the energy storage battery. The voltage conversion circuit is used to convert the DC power output by the charging control chip to obtain a suitable first charging voltage for charging the energy storage battery.

[0006] In one possible design, the wireless charging and discharging circuit includes three voltage conversion circuits, namely a first voltage conversion branch, a second voltage conversion branch, and a third voltage conversion branch. The first voltage conversion branch includes a third disconnect switch and a first voltage conversion chip. The first end of the third disconnect switch is connected to the voltage output pin of the charging control chip, the second end of the third disconnect switch is connected to the input end of the first voltage conversion chip, and the output end of the first voltage conversion chip is connected to the charging end of the energy storage battery. The second voltage conversion branch includes a fourth disconnect switch and a second voltage conversion chip. The first end of the fourth disconnect switch is connected to the voltage output pin of the charging control chip, the second end of the fourth disconnect switch is connected to the input end of the second voltage conversion chip, and the output end of the second voltage conversion chip is connected to the charging end of the energy storage battery. The third voltage conversion branch includes a third voltage conversion chip, the second terminal of the fourth disconnect switch is connected to the input terminal of the third voltage conversion chip, and the output terminal of the third voltage conversion chip is connected to the charging terminal of the energy storage battery. The control terminal of the third disconnecting switch is used to receive a third on / off control signal, which is used to control the on and off states of the third disconnecting switch; the control terminal of the fourth disconnecting switch is used to receive a fourth on / off control signal, which is used to control the on and off states of the fourth disconnecting switch.

[0007] In one possible design, the second bootstrap circuit includes an optocoupler, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor; The anode of the first diode is connected to the second isolating switch, the anode of the third diode, the first terminal of the first capacitor, and the anode of the fifth diode. The cathode of the first diode is connected to the anode of the second diode and the first terminal of the first resistor. The second terminal of the first resistor is connected to the first terminal of the charging receiving coil. The cathode of the second diode is connected to the cathode of the fourth diode, the second terminal of the first capacitor, and the first terminal of the third resistor. The anode of the fourth diode is connected to the cathode of the third diode and the first terminal of the second resistor. The second terminal of the second resistor is connected to the second terminal of the charging receiving coil. The second terminal of the third resistor is connected to the cathode of the fifth diode. The positive terminal of the light source of the optocoupler is connected to the power supply pin on the charging control chip to receive the power supply voltage output by the power supply pin. The negative terminal of the light source is connected to the fifth voltage reference pin on the charging control chip. The first end of the light receiver of the optocoupler is connected to the first end of the third resistor, and the second end of the light receiver is connected to the positive terminal of the fifth diode.

[0008] In one possible design, both the first resonant compensation circuit and the second resonant compensation circuit are capacitive resonant compensation circuits, wherein the capacitive resonant compensation circuit includes at least one resonant capacitor.

[0009] In one possible design, the first resonant compensation circuit includes a tenth capacitor, an eleventh capacitor, a twelfth capacitor, and a thirteenth capacitor. The first end of the tenth capacitor, the first end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor are all connected to the second end of the charging transmitter coil, and the second end of the tenth capacitor, the second end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor are all connected to the first end of the first disconnecting switch.

[0010] In one possible design, the second resonant compensation circuit includes a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, and a ninth capacitor. The first terminal of the second capacitor, the first terminal of the third capacitor, the first terminal of the fourth capacitor, the first terminal of the fifth capacitor, the first terminal of the sixth capacitor, the first terminal of the seventh capacitor, the first terminal of the eighth capacitor, and the first terminal of the ninth capacitor are all connected to the second terminal of the charging receiving coil. The second terminal of the second capacitor, the second terminal of the third capacitor, the second terminal of the fourth capacitor, the second terminal of the fifth capacitor, the second terminal of the sixth capacitor, the second terminal of the seventh capacitor, the second terminal of the eighth capacitor, and the second terminal of the ninth capacitor are all connected to the first terminal of the second disconnecting switch.

[0011] In one possible design, the first disconnecting switch includes a first transistor and a second transistor; the first terminal of the first transistor is the second terminal of the first disconnecting switch, and the first terminal of the first transistor is connected to the second control pin of the charging control chip; the second terminal of the first transistor is connected to the second terminal of the second transistor, the first terminal of the second transistor is the first terminal of the first disconnecting switch, and the first terminal of the second transistor is connected to the second terminal of the first resonant compensation circuit. The second disconnecting switch includes a third transistor and a fourth transistor; the first terminal of the third transistor is the second terminal of the second disconnecting switch, and the first terminal of the third transistor is connected to the second control pin of the charging control chip; the second terminal of the third transistor is connected to the second terminal of the fourth transistor, the first terminal of the fourth transistor is the first terminal of the second disconnecting switch, and the first terminal of the fourth transistor is connected to the second terminal of the second resonant compensation circuit.

[0012] In one possible design, the third isolating switch includes a fifth transistor and a sixth transistor; the first terminal of the fifth transistor is the first terminal of the third isolating switch, and the first terminal of the fifth transistor is connected to the voltage output pin of the charging control chip; the second terminal of the fifth transistor is connected to the second terminal of the sixth transistor, the first terminal of the sixth transistor is the second terminal of the third isolating switch, and the first terminal of the sixth transistor is connected to the input terminal of the first voltage conversion chip. The fourth isolating switch includes a seventh transistor and an eighth transistor; the first terminal of the seventh transistor is the first terminal of the fourth isolating switch, and the first terminal of the seventh transistor is connected to the voltage output pin of the charging control chip; the second terminal of the eighth transistor is connected to the second terminal of the seventh transistor, the first terminal of the eighth transistor is the second terminal of the fourth isolating switch, and the first terminal of the eighth transistor is connected to the input terminal of the second voltage conversion chip.

[0013] Secondly, this application also provides a chip, the chip including the wireless charging and discharging circuit as described in any of the preceding claims.

[0014] Thirdly, this application also provides an electronic device, which includes a wireless charging and discharging circuit as described in any of the preceding claims.

[0015] The wireless charging and discharging circuit provided in the first aspect above includes: a charging receiving coil, a charging transmitting coil, a first resonant compensation circuit, a second resonant compensation circuit, a first isolating switch, a second isolating switch, a first bootstrap circuit, a second bootstrap circuit, and a charging control chip; wherein, a first end of the charging transmitting coil is connected to a first control pin of the charging control chip, a second end of the charging transmitting coil is connected to a first end of the first resonant compensation circuit, a second end of the first resonant compensation circuit is connected to a first end of the first isolating switch, and a second end of the first isolating switch is connected to a second control pin of the charging control chip; the output end of the first bootstrap circuit is connected to the control end of the first isolating switch, and a first end of the first bootstrap circuit is connected to a first bootstrap capacitor pin on the charging control chip; the first bootstrap circuit is used to sample electrical energy to output a first on / off control. The circuit comprises a first on / off control signal, used to control the conduction or cutoff of the first isolating switch, thereby controlling whether the charging transmitting coil is connected to the working circuit; a first end of the charging receiving coil is connected to the first control pin of the charging control chip, a second end of the charging receiving coil is connected to the first end of the second resonant compensation circuit, a second end of the second resonant compensation circuit is connected to the first end of the second isolating switch, and a second end of the second isolating switch is connected to the second control pin of the charging control chip; the output end of the second bootstrap circuit is connected to the control end of the second isolating switch, and the first and second input ends of the second bootstrap circuit are respectively connected to the first and second ends of the charging receiving coil; the second bootstrap circuit is used to sample electrical energy to output a second on / off control signal, which is used to control the conduction or cutoff of the second isolating switch, thereby controlling whether the charging receiving coil is connected to the working circuit. It can be seen that the wireless charging and discharging circuit provided in this application uses a structure of a charging receiving coil, a charging transmitting coil, and a charging control chip instead of two wireless charging chips in related technologies, enabling wireless charging of electronic devices and reverse wireless charging of styluses, thus saving hardware costs.

[0016] The beneficial effects provided by the other aspects and the various possible designs of the other aspects can be found in the beneficial effects of the first aspect and the various possible implementations of the first aspect, and will not be repeated here. Attached Figure Description

[0017] Figure 1 This is one of the schematic diagrams of the wireless charging and discharging circuit structure provided in the embodiments of this application; Figure 2 This is a second schematic diagram of the wireless charging and discharging circuit structure provided in the embodiments of this application; Figure 3 This is one of the schematic diagrams of the second bootstrap circuit structure provided in the embodiments of this application; Figure 4 This is a second schematic diagram of the second bootstrap circuit structure provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the first resonant compensation circuit provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of the first resonant compensation circuit provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of the first disconnecting switch provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of the second disconnecting switch provided in an embodiment of this application; Figure 9 This is a partial structural diagram of the first bootstrap circuit in an embodiment of this application. Detailed Implementation

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

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

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

[0021] The transistor in this application is a three-terminal transistor, with its three terminals being a control terminal, a first terminal, and a second terminal. The transistor can be a bipolar transistor (BPT) or a field-effect transistor (FET), etc. For example, when the transistor is a BPT, its control terminal is the base of the BPT, the first terminal can be the collector or emitter of the BPT, and the corresponding second terminal can be the emitter or collector of the BPT; when the transistor is a FET, its control terminal is the gate of the FET, the first terminal can be the drain or source of the FET, and the corresponding second terminal can be the source or drain of the FET.

[0022] For electronic devices with styluses, in order to achieve wireless charging of the electronic device and the stylus, related technologies require two wireless charging chips to be installed inside the electronic device. One wireless charging chip is used to receive the wireless power output from the wireless charging dock to charge the energy storage battery in the tablet, and the other wireless charging chip is used to receive the reverse discharge of the energy storage battery to charge the stylus that comes with the tablet. However, the need to equip two wireless charging chips results in high hardware costs for the circuit and occupies a large space inside the electronic device.

[0023] To overcome the shortcomings of the aforementioned related technologies, this application provides a wireless charging and discharging circuit for electronic devices. Since some functions and circuit structures of the two wireless charging chips in the related technologies are similar or overlapping, in order to save hardware costs, the wireless charging circuit of this application integrates the same circuit parts of the two wireless charging chips into a single charging control chip. Then, the two wireless charging coils are isolated by an isolating switch. Thus, such a charging control chip can control the operation of the two wireless charging coils to achieve wireless charging of the energy storage battery in the electronic device during one period and wireless charging of the stylus in the electronic device during another period. This saves hardware costs, simplifies the structure of the wireless charging circuit, and saves space inside the electronic device.

[0024] Figure 1 For one of the schematic diagrams of the wireless charging and discharging circuit structure provided in the embodiments of this application, please refer to [link / reference]. Figure 1 As shown, this application provides a wireless charging and discharging circuit for use in electronic devices. The wireless charging and discharging circuit includes: a charging receiving coil L2, a charging transmitting coil L1, a first resonant compensation circuit 10, a second resonant compensation circuit 14, a first isolating switch 11, a second isolating switch 15, a first bootstrap circuit 12, a second bootstrap circuit 16, and a charging control chip 17. The first end of the charging transmitting coil L1 is connected to the first control pin AC2 of the charging control chip 17, and the second end of the charging transmitting coil L1 is connected to the first end of the first resonant compensation circuit 10. The second end of the vibration compensation circuit 10 is connected to the first end of the first isolating switch 11, and the second end of the first isolating switch 11 is connected to the second control pin AC1 of the charging control chip 17; the output end of the first bootstrap circuit 12 is connected to the control end of the first isolating switch 11, and the first end of the first bootstrap circuit 12 is connected to the first bootstrap capacitor pin BST1 on the charging control chip 17; the first bootstrap circuit 12 is used to sample electrical energy to output a first on / off control signal, which is used to control the conduction or off of the first isolating switch 11, thereby controlling whether the charging transmitter coil L1 is connected to work.

[0025] The charging receiving coil L2 has its first end connected to the first control pin AC2 of the charging control chip 17, and its second end connected to the first end of the second resonant compensation circuit 14. The second end of the second resonant compensation circuit 14 is connected to the first end of the second isolating switch 15, and the second end of the second isolating switch 15 is connected to the second control pin AC1 of the charging control chip 17. The output end of the second bootstrap circuit 16 is connected to the control end of the second isolating switch 15, and the first and second input ends of the second bootstrap circuit 15 are respectively connected to the first and second ends of the charging receiving coil L2. The second bootstrap circuit 16 is used to sample electrical energy to output a second on / off control signal. The second on / off control signal is used to control the conduction or deactivation of the second isolating switch 15, thereby controlling whether the charging receiving coil L2 is connected to the working circuit.

[0026] The wireless charging and discharging circuit provided in the embodiments of this application replaces the two wireless charging chips in the related technology with a structure of charging receiving coil L2, charging transmitting coil L1 and charging control chip 17. This can achieve wireless charging of electronic devices and reverse wireless charging of styluses, saving hardware costs of the circuit and saving internal space of electronic devices.

[0027] Furthermore, in this embodiment, a first isolating switch 11 is connected in series in the wireless charging circuit where the charging transmitting coil L1 is located, and a second isolating switch 15 is connected in series in the wireless charging circuit where the charging receiving coil L2 is located. When the energy storage battery in the electronic device is charged through an external wireless charging base, the second isolating switch 15 can be controlled to be in the conducting state, while the first isolating switch 11 is controlled to be closed. This allows the charging receiving coil L2 to receive the electrical energy transmitted by the wireless charging base to charge the energy storage battery in the electronic device. When the stylus is charged in reverse through the energy storage battery in the electronic device, the first isolating switch 11 can be controlled to be in the conducting state, while the second isolating switch 15 is controlled to be closed. This allows the charging transmitting coil L1 to receive the electrical energy in the energy storage battery to charge the stylus in reverse.

[0028] In addition, this application embodiment also includes a first resonant compensation circuit 10 to perform resonant compensation when the charging transmitting coil L1 is working, and a second resonant compensation circuit 14 to perform resonant compensation when the charging receiving coil L2 is working. At the same time, this application includes a first bootstrap circuit 12 to sample energy to control the conduction and cutoff of the first isolation switch 11, and a second bootstrap circuit 16 to sample energy to control the conduction and cutoff of the second isolation switch 15. This allows the conduction of the two wireless charging branches to be controlled even when the circuit is initially powered on (i.e., the energy storage battery is completely depleted), thereby realizing wireless charging of electronic devices and reverse wireless charging of styluses.

[0029] In one embodiment of this application, the wireless charging and discharging circuit further includes at least one voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the voltage output pin of the charging control chip 17. The charging control chip 17 rectifies the received AC power into a corresponding DC power. The output terminal of the voltage conversion circuit is connected to the charging terminal of the energy storage battery. The voltage conversion circuit is used to perform voltage conversion on the DC power output by the charging control chip, for example, to step down the DC power output by the charging control chip to obtain a suitable first charging voltage for charging the energy storage battery.

[0030] Figure 2 For the second schematic diagram of the wireless charging and discharging circuit structure provided in the embodiments of this application, please refer to [link / reference]. Figure 2 As shown, the wireless charging and discharging circuit provided in this application embodiment includes three voltage conversion circuits, namely a first voltage conversion branch, a second voltage conversion branch, and a third voltage conversion branch. The three voltage conversion circuits are arranged in parallel. Under one working condition, any one of the three voltage conversion circuits works to output a larger charging current, thereby improving the charging efficiency of the internal energy storage battery of the electronic device.

[0031] Please continue reading Figure 2As shown, the first voltage conversion branch provided in this application embodiment includes a third disconnect switch 18 and a first voltage conversion chip 20. The first end of the third disconnect switch 18 is connected to the voltage output pin VOUT of the charging control chip 17, the second end of the third disconnect switch 18 is connected to the input end of the first voltage conversion chip 20, and the output end of the first voltage conversion chip 20 is connected to the charging end of the energy storage battery 23.

[0032] The second voltage conversion branch includes a fourth disconnect switch 19 and a second voltage conversion chip 21. The first end of the fourth disconnect switch 19 is connected to the voltage output pin VOUT of the charging control chip 17, the second end of the fourth disconnect switch 19 is connected to the input end of the second voltage conversion chip 21, and the output end of the second voltage conversion chip 21 is connected to the charging end of the energy storage battery 23.

[0033] The third voltage conversion branch includes a third voltage conversion chip 22, the second terminal of the fourth disconnect switch 19 is connected to the input terminal of the third voltage conversion chip 22, and the output terminal of the third voltage conversion chip 22 is connected to the charging terminal of the energy storage battery 23.

[0034] The control terminal of the third disconnect switch 18 is used to receive the third on / off control signal output by the charging control chip 17. The third on / off control signal is used to control the on and off of the third disconnect switch 18. The control terminal of the fourth disconnect switch 19 is used to receive the fourth on / off control signal output by the charging control chip 17. The fourth on / off control signal is used to control the on and off of the fourth disconnect switch 19.

[0035] Understandably, when it is necessary to control the operation of the branch containing the first voltage conversion chip 20, the charging control chip 17 can output a conduction control signal to control the third isolating switch 18 to conduct, thereby controlling the first voltage conversion chip 20 to operate and convert the DC power output by the charging control chip 17 to charge the energy storage battery 22. When it is necessary to control the operation of the branches containing the second voltage conversion chip 21 and the third voltage conversion chip 22, the charging control chip 17 can output a conduction control signal to control the fourth isolating switch 19 to conduct, thereby controlling the second voltage conversion chip 21 and the third voltage conversion chip 22 to operate and convert the DC power output by the charging control chip 17 to charge the energy storage battery 22.

[0036] In this embodiment, the first voltage conversion chip 20, the second voltage conversion chip 21, and the third voltage conversion chip 22 can be common charge pump chips or DC-DC voltage conversion chips to achieve voltage conversion. The voltage conversion ratio of the first voltage conversion chip 20, the second voltage conversion chip 21, and the third voltage conversion chip 22 can be selected according to the actual circuit requirements, which will not be elaborated here.

[0037] Figure 3 This is one of the schematic diagrams of the second bootstrap circuit structure provided in the embodiments of this application. Figure 4 For a second schematic diagram of the second bootstrap circuit structure provided in the embodiments of this application, please refer to [link / reference]. Figure 3 and Figure 4 As shown, the second bootstrap circuit 16 provided in this embodiment includes an optocoupler U1, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1; wherein, the positive terminal of the first diode D1 is connected to the first isolating switch 11, the positive terminal of the third diode D3, the first terminal of the first capacitor C1, and the positive terminal of the fifth diode D5; the negative terminal of the first diode D1 is connected to the positive terminal of the second diode D2 and the first terminal of the first resistor R1, and the second terminal of the first resistor R1 is connected to the first terminal AC2 of the charging receiving coil L2; the negative terminal of the second diode D2 is connected to the negative terminal of the fourth diode D4, the second terminal of the first capacitor C1, and the first terminal of the third resistor R3, and the fourth... The positive terminal of diode D4 is connected to the negative terminal of third diode D3 and the first terminal of second resistor R2. The second terminal of second resistor R2 is connected to the second terminal of charging receiving coil L2. The second terminal of third resistor R3 is connected to the negative terminal of fifth diode D5. The positive terminal of the light source (specifically a light-emitting diode in this embodiment) of optocoupler U1 is connected to the power supply pin V5V on the charging control chip 17 to receive the power supply voltage (specifically 5V voltage) output by the power supply pin V5V. The negative terminal of the light source is connected to the fifth voltage reference pin RX_GP5 on the charging control chip 17 through fourth resistor R4. The fourth resistor R4 mainly serves to limit current. The first terminal of the photodetector of optocoupler U1 is connected to the first terminal RX_CBOOT of third resistor R3, and the second terminal of the photodetector is connected to the positive terminal RX_CBOOT- of fifth diode D5.

[0038] It is understandable that by controlling the on and off of the optocoupler U1, the second bootstrap circuit 16 can be further controlled to operate, thereby enabling the second bootstrap circuit 16 to control the on and off of the second disconnect switch 15.

[0039] In the dead-end activation scenario, the entire tablet is without power. The first point to gain power is the charging receiving coil L2. Therefore, this solution uses the two ends of the charging receiving coil L2 as a rectifier circuit, which performs floating bootstrap charging. The induced electromotive force does not require a circuit and will be generated automatically by mutual inductance. The charging circuit uses current-limiting resistors on both sides of the AC circuit for current limiting. When the induced voltage is higher than the Cboot voltage, charging will continue. The two ends of the Cboot voltage are connected to the optocoupler U1 via floating ground, and then connected to the discharge circuit via floating ground. The discharge circuit consists of a Zener diode and a current-limiting resistor. At this time, the input current-limiting impedance is greater than the discharge current-limiting impedance, so when the Zener diode is conducting, the CBOOT discharge rate is always greater than the charging rate. Specifically, in this embodiment, a 5V Zener diode can be selected, with a voltage drop provided by a 4.5KΩ series impedance. At this time, the CBOOT voltage will be stabilized at 5V + 1.5K * discharge current. Under normal high-power operation, the discharge current may be 5-10mA, and the peak coil voltage is 27.5V-50V.

[0040] In one embodiment of this application, the first resonant compensation circuit 10 and the second resonant compensation circuit 14 are both capacitor resonant compensation circuits. Each capacitor resonant compensation circuit includes at least one resonant capacitor, which, together with the charging transmitting coil L1 or the charging receiving coil L2, forms an LC resonant circuit.

[0041] Figure 5 For a schematic diagram of the first resonant compensation circuit provided in the embodiments of this application, please refer to [link / reference]. Figure 5 As shown, the first resonant compensation circuit 10 provided in this embodiment includes a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, and a thirteenth capacitor C13; wherein, the first end of the tenth capacitor C10, the first end of the eleventh capacitor C11, the first end of the twelfth capacitor C12, and the first end of the thirteenth capacitor C13 are all connected to the second end VTANK of the charging and transmitting coil L1, and the second end of the tenth capacitor C10, the second end of the eleventh capacitor C11, the first end of the twelfth capacitor C12, and the first end of the thirteenth capacitor C13 are all connected to the first end AC1_TX of the first disconnecting switch.

[0042] It is understood that the first resonant compensation circuit 10 in this embodiment is composed of four capacitors connected in parallel. In other embodiments, the first resonant compensation circuit 10 may also be composed of other numbers of capacitors connected in parallel as needed.

[0043] Figure 6 For a schematic diagram of the first resonant compensation circuit provided in the embodiments of this application, please refer to [link / reference]. Figure 6As shown, the second resonant compensation circuit 14 provided in this embodiment includes a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, and a ninth capacitor C9. The first terminals of the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor C9 are all connected to the second terminal RX_VTANK of the charging receiving coil L2. The second terminals of the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor C9 are all connected to the first terminal AC1_RX of the second isolating switch 15.

[0044] It is understood that the second resonant compensation circuit 14 in this embodiment is composed of eight capacitors connected in parallel. In other embodiments, the second resonant compensation circuit 14 may also be composed of other numbers of capacitors connected in parallel as needed.

[0045] Figure 7 For a schematic diagram of the structure of the first disconnecting switch provided in the embodiments of this application, please refer to [link / reference]. Figure 7 As shown, the first isolation switch 11 provided in this embodiment includes a first transistor Q1 and a second transistor Q2; the first terminal of the first transistor Q1 is the second terminal of the first isolation switch 11, and the first terminal of the first transistor Q1 is connected to the second control pin AC1 of the charging control chip 17; the second terminal of the first transistor Q1 is connected to the second terminal of the second transistor Q2, the first terminal of the second transistor Q2 is the first terminal of the first isolation switch 11, and the first terminal of the second transistor Q2 is connected to the second terminal of the first resonant compensation circuit 10; and the second terminals of the first transistor Q1 and the second terminals of the second transistor Q2 are connected to the GATE_TX pin of the charging control chip 17 through the fifth resistor R5, and the GATE_TX pin is specifically the resonant capacitor pin.

[0046] In this embodiment, the first transistor Q1 and the second transistor Q2 in the first disconnecting switch 11 can be NMOS (N-Metal-Oxide-Semiconductor) transistors; in other embodiments, the first transistor Q1 and the second transistor Q2 can also be PMOS (P-Metal-Oxide-Semiconductor) transistors. For example, when the first transistor Q1 and the second transistor Q2 are NMOS transistors, their first electrode is the drain, their second electrode is the source, and their control electrode is the gate.

[0047] Figure 8For a schematic diagram of the structure of the second disconnecting switch provided in the embodiments of this application, please refer to [link / reference]. Figure 8 As shown, the second isolating switch 15 provided in this embodiment includes a third transistor Q3 and a fourth transistor Q4; the first terminal of the third transistor Q3 is the second terminal of the second isolating switch 15, and the first terminal of the third transistor Q3 is connected to the second control pin AC1 of the charging control chip 17; the second terminal of the third transistor Q3 is connected to the second terminal of the fourth transistor Q4, the first terminal of the fourth transistor Q4 is the first terminal of the second isolating switch 15, and the first terminal of the fourth transistor Q4 is connected to the second terminal AC1_RX of the second resonant compensation circuit. The second terminals of the third transistor Q3 and the fourth transistor Q4 are connected to the positive terminal of the first diode D1.

[0048] In this embodiment, the third transistor Q3 and the fourth transistor Q4 in the second isolation switch 15 can be NMOS (N-Metal-Oxide-Semiconductor) transistors; in other embodiments, the third transistor Q3 and the fourth transistor Q4 can also be PMOS (P-Metal-Oxide-Semiconductor) transistors. For example, when the third transistor Q3 and the fourth transistor Q4 are NMOS transistors, their first electrode is the drain, their second electrode is the source, and their control electrode is the gate.

[0049] Upon the initial digital ping received from the charging transmitter coil L1, the two back-to-back NMOS transistors on the L1 circuit exhibit high resistance. At this point, the induced electromotive force of the charging receiver coil L2 can only be used to charge the energy storage battery. As the C_BOOT+ voltage rises, the two back-to-back NMOS transistors on the branch containing the charging receiver coil L2 conduct. The voltage across the NMOS transistors gradually decreases, while the current gradually increases, and the charging receiver coil L2 begins rectification. Throughout this process, C_BOOT remains stable at approximately 5V. When a current signal is input to the optocoupler U1, C_BOOT is quickly pulled low by the optocoupler, and the rectifier circuit shuts off.

[0050] When the RX chip is de-energized, the two NMOS transistors in the branch containing the charging receiving coil L2 are normally on. When the RX chip is energized, optocoupler U1 can be used to control the charging and discharging of the C_BOOT rectifier circuit, thereby achieving path selection. When the RX chip is energized, controlling the high and low levels of GP5 can be used to control the on / off state of the optocoupler, thus completing path selection. The NMOS transistors in the charging receiving coil L2 branch can be driven using a conventional CSMD transistor. Since RX is always energized in TX mode, there are several ways to enable back-to-back operation. Using a PNP-NPN driver, BST1 and the back-to-back MOS gate stage can be connected to enable conduction when needed. This is relatively conventional and will not be elaborated further here.

[0051] Please continue reading Figure 2 As shown in the embodiment of this application, the third isolating switch 18 includes a fifth transistor Q5 and a sixth transistor Q6. The first terminal of the fifth transistor Q5 is the first terminal of the third isolating switch 18, and the first terminal of the fifth transistor Q5 is connected to the voltage output pin VOUT of the charging control chip 17. The second terminal of the fifth transistor Q5 is connected to the second terminal of the sixth transistor Q6, and the first terminal of the sixth transistor Q6 is the second terminal of the third isolating switch 18. The first terminal of the sixth transistor Q6 is connected to the input terminal of the first voltage conversion chip 20. The control terminals of the fifth transistor Q5 and the sixth transistor Q6 are both used to receive corresponding on / off control signals, which are used to control the conduction or deactivation of the fifth transistor Q5 and the sixth transistor Q6.

[0052] In this embodiment, the fifth transistor Q5 and the sixth transistor Q6 in the third isolating switch 18 can be NMOS (N-Metal-Oxide-Semiconductor) transistors; in other embodiments, the fifth transistor Q5 and the sixth transistor Q6 can also be PMOS (P-Metal-Oxide-Semiconductor) transistors. For example, when the fifth transistor Q5 and the sixth transistor Q6 are NMOS transistors, their first electrode is the drain, their second electrode is the source, and their control electrode is the gate.

[0053] Please continue reading Figure 2 As shown in the embodiment of this application, the fourth isolating switch 19 includes a seventh transistor Q7 and an eighth transistor Q8. The first terminal of the seventh transistor Q7 is the first terminal of the fourth isolating switch 19, and the first terminal of the seventh transistor Q7 is connected to the voltage output pin VOUT of the charging control chip 17. The second terminal of the eighth transistor Q8 is connected to the second terminal of the seventh transistor Q7, and the first terminal of the eighth transistor Q8 is the second terminal of the fourth isolating switch 19. The first terminal of the eighth transistor Q8 is connected to the input terminal of the second voltage conversion chip 21. The control terminals of the seventh transistor Q7 and the eighth transistor Q8 are both used to receive corresponding on / off control signals, which are used to control the conduction or deactivation of the seventh transistor Q7 and the eighth transistor Q8.

[0054] In this embodiment, the seventh transistor Q7 and the eighth transistor Q8 in the fourth isolating switch 19 can be NMOS (N-Metal-Oxide-Semiconductor) transistors; in other embodiments, the seventh transistor Q7 and the eighth transistor Q8 can also be PMOS (P-Metal-Oxide-Semiconductor) transistors. For example, when the seventh transistor Q7 and the eighth transistor Q8 are NMOS transistors, their first electrode is the drain, their second electrode is the source, and their control electrode is the gate.

[0055] In this embodiment, the isolating switch circuits all adopt a back-to-back transistor configuration, which can prevent reverse current breakdown and ensure the safe operation of the circuit.

[0056] Figure 9 This is a partial structural diagram of the first bootstrap circuit in an embodiment of this application. Please refer to [link / reference]. Figure 9 As shown, in this embodiment, the first terminal of the first bootstrap circuit 12 is connected to the first bootstrap capacitor pin BST1 on the charging control chip 17 via the fifteenth capacitor C15; the gates of the first transistor Q1 and the second transistor Q2 are both connected to the bootstrap capacitor pin CSMD on the charging control chip 17. Additionally, the charging control chip 17 includes a sixth resistor R6 and a nineteenth diode D19. The first terminal of the sixth resistor R6 receives a 5V supply voltage, and the second terminal of the sixth resistor R6 is connected to the anode of the nineteenth diode D19. The cathode of the nineteenth diode D19 is the first bootstrap capacitor pin BST1.

[0057] This application also provides a chip that includes the wireless charging and discharging circuit provided in any of the above embodiments. This chip can achieve wireless charging of electronic devices and reverse wireless charging of styluses, saving hardware costs and internal space in the electronic device.

[0058] This application also provides an electronic device, such as a tablet computer or mobile phone, which includes a wireless charging and discharging circuit as provided in any of the above embodiments. This electronic device can achieve wireless charging and reverse wireless charging of a stylus, saving hardware costs and internal space.

[0059] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wireless charging and discharging circuit, said wireless charging and discharging circuit being used in electronic devices, characterized in that, The wireless charging and discharging circuit includes: a charging receiving coil, a charging transmitting coil, a first resonant compensation circuit, a second resonant compensation circuit, a first isolation switch, a second isolation switch, a first bootstrap circuit, a second bootstrap circuit, and a charging control chip. The first end of the charging transmitting coil is connected to the first control pin of the charging control chip; the second end of the charging transmitting coil is connected to the first end of the first resonant compensation circuit; the second end of the first resonant compensation circuit is connected to the first end of the first isolating switch; and the second end of the first isolating switch is connected to the second control pin of the charging control chip. The output end of the first bootstrap circuit is connected to the control end of the first isolating switch; and the first end of the first bootstrap circuit is connected to the first bootstrap capacitor pin on the charging control chip. The first bootstrap circuit is used to sample electrical energy to output a first on / off control signal. The first on / off control signal is used to control the conduction or deactivation of the first isolating switch, thereby controlling whether the charging transmitting coil is connected for operation. The first end of the charging receiving coil is connected to the first control pin of the charging control chip, the second end of the charging receiving coil is connected to the first end of the second resonant compensation circuit, the second end of the second resonant compensation circuit is connected to the first end of the second isolating switch, and the second end of the second isolating switch is connected to the second control pin of the charging control chip; the output end of the second bootstrap circuit is connected to the control end of the second isolating switch, and the first and second input ends of the second bootstrap circuit are respectively connected to the first and second ends of the charging receiving coil; the second bootstrap circuit is used to sample electrical energy to output a second on / off control signal, which is used to control the conduction or deactivation of the second isolating switch, thereby controlling whether the charging receiving coil is connected for operation.

2. The wireless charging and discharging circuit according to claim 1, characterized in that, The wireless charging and discharging circuit further includes at least one voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the voltage output pin of the charging control chip, and the output terminal of the voltage conversion circuit is connected to the charging terminal of the energy storage battery. The voltage conversion circuit is used to convert the DC power output by the charging control chip to obtain a suitable first charging voltage for charging the energy storage battery.

3. The wireless charging and discharging circuit according to claim 2, characterized in that, The wireless charging and discharging circuit includes three voltage conversion circuits, namely a first voltage conversion branch, a second voltage conversion branch, and a third voltage conversion branch. The first voltage conversion branch includes a third disconnect switch and a first voltage conversion chip. The first end of the third disconnect switch is connected to the voltage output pin of the charging control chip, the second end of the third disconnect switch is connected to the input end of the first voltage conversion chip, and the output end of the first voltage conversion chip is connected to the charging end of the energy storage battery. The second voltage conversion branch includes a fourth disconnect switch and a second voltage conversion chip. The first end of the fourth disconnect switch is connected to the voltage output pin of the charging control chip, the second end of the fourth disconnect switch is connected to the input end of the second voltage conversion chip, and the output end of the second voltage conversion chip is connected to the charging end of the energy storage battery. The third voltage conversion branch includes a third voltage conversion chip, the second terminal of the fourth disconnect switch is connected to the input terminal of the third voltage conversion chip, and the output terminal of the third voltage conversion chip is connected to the charging terminal of the energy storage battery. The control terminal of the third disconnecting switch is used to receive a third on / off control signal, which is used to control the on and off states of the third disconnecting switch; the control terminal of the fourth disconnecting switch is used to receive a fourth on / off control signal, which is used to control the on and off states of the fourth disconnecting switch.

4. The wireless charging and discharging circuit according to claim 1, characterized in that, The second bootstrap circuit includes an optocoupler, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor; The anode of the first diode is connected to the second isolating switch, the anode of the third diode, the first terminal of the first capacitor, and the anode of the fifth diode. The cathode of the first diode is connected to the anode of the second diode and the first terminal of the first resistor. The second terminal of the first resistor is connected to the first terminal of the charging receiving coil. The cathode of the second diode is connected to the cathode of the fourth diode, the second terminal of the first capacitor, and the first terminal of the third resistor. The anode of the fourth diode is connected to the cathode of the third diode and the first terminal of the second resistor. The second terminal of the second resistor is connected to the second terminal of the charging receiving coil. The second terminal of the third resistor is connected to the cathode of the fifth diode. The positive terminal of the light source of the optocoupler is connected to the power supply pin on the charging control chip to receive the power supply voltage output by the power supply pin. The negative terminal of the light source is connected to the fifth voltage reference pin on the charging control chip. The first end of the light receiver of the optocoupler is connected to the first end of the third resistor, and the second end of the light receiver is connected to the positive terminal of the fifth diode.

5. The wireless charging and discharging circuit according to claim 2, characterized in that, Both the first resonant compensation circuit and the second resonant compensation circuit are capacitor resonant compensation circuits, and the capacitor resonant compensation circuit includes at least one resonant capacitor.

6. The wireless charging and discharging circuit according to claim 5, characterized in that, The first resonant compensation circuit includes a tenth capacitor, an eleventh capacitor, a twelfth capacitor, and a thirteenth capacitor; The first end of the tenth capacitor, the first end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor are all connected to the second end of the charging transmitter coil, and the second end of the tenth capacitor, the second end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor are all connected to the first end of the first disconnecting switch.

7. The wireless charging and discharging circuit according to claim 5, characterized in that, The second resonant compensation circuit includes a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, and a ninth capacitor; The first terminal of the second capacitor, the first terminal of the third capacitor, the first terminal of the fourth capacitor, the first terminal of the fifth capacitor, the first terminal of the sixth capacitor, the first terminal of the seventh capacitor, the first terminal of the eighth capacitor, and the first terminal of the ninth capacitor are all connected to the second terminal of the charging receiving coil. The second terminal of the second capacitor, the second terminal of the third capacitor, the second terminal of the fourth capacitor, the second terminal of the fifth capacitor, the second terminal of the sixth capacitor, the second terminal of the seventh capacitor, the second terminal of the eighth capacitor, and the second terminal of the ninth capacitor are all connected to the first terminal of the second disconnecting switch.

8. The wireless charging and discharging circuit according to claim 5, characterized in that, The first disconnect switch includes a first transistor and a second transistor; the first terminal of the first transistor is the second terminal of the first disconnect switch, and the first terminal of the first transistor is connected to the second control pin of the charging control chip; the second terminal of the first transistor is connected to the second terminal of the second transistor, the first terminal of the second transistor is the first terminal of the first disconnect switch, and the first terminal of the second transistor is connected to the second terminal of the first resonant compensation circuit. The second disconnecting switch includes a third transistor and a fourth transistor; the first terminal of the third transistor is the second terminal of the second disconnecting switch, and the first terminal of the third transistor is connected to the second control pin of the charging control chip; the second terminal of the third transistor is connected to the second terminal of the fourth transistor, the first terminal of the fourth transistor is the first terminal of the second disconnecting switch, and the first terminal of the fourth transistor is connected to the second terminal of the second resonant compensation circuit.

9. The wireless charging and discharging circuit according to claim 3, characterized in that, The third isolating switch includes a fifth transistor and a sixth transistor; the first terminal of the fifth transistor is the first terminal of the third isolating switch, and the first terminal of the fifth transistor is connected to the voltage output pin of the charging control chip; the second terminal of the fifth transistor is connected to the second terminal of the sixth transistor, the first terminal of the sixth transistor is the second terminal of the third isolating switch, and the first terminal of the sixth transistor is connected to the input terminal of the first voltage conversion chip. The fourth isolating switch includes a seventh transistor and an eighth transistor; the first terminal of the seventh transistor is the first terminal of the fourth isolating switch, and the first terminal of the seventh transistor is connected to the voltage output pin of the charging control chip; the second terminal of the eighth transistor is connected to the second terminal of the seventh transistor, the first terminal of the eighth transistor is the second terminal of the fourth isolating switch, and the first terminal of the eighth transistor is connected to the input terminal of the second voltage conversion chip.

10. A chip, characterized in that, The chip includes the wireless charging and discharging circuit as described in any one of claims 1-9.

11. An electronic device, characterized in that, The electronic device includes the wireless charging and discharging circuit as described in any one of claims 1-9.

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