A charging control method, electronic device, and wireless charging system

Abstract

The embodiment of the application provides a charging control method, an electronic device and a wireless charging system, relates to the technical field of wireless charging, and is used for improving voltage conversion efficiency and solving the problem of rising device cost caused by setting multiple direct-current voltage reduction circuits in a wireless charging device. The electronic device comprises a receiving coil, a wireless power receiver, a three-level voltage reduction circuit, a battery and a receiving end controller. The charging control method comprises the following steps: the receiving end controller acquires a battery voltage, and sends a first control signal and a second control signal according to the battery voltage. The wireless power receiver converts alternating current generated by the receiving coil into direct current according to the first control signal, outputs a first voltage V1, and performs first voltage mode charging on the battery. The three-level voltage reduction circuit reduces the voltage output by the wireless power receiver according to the second control signal and then outputs the voltage to the battery. The charging voltage received by the battery is the acquired battery voltage.

Description

Technical Field

[0001] This application relates to the field of wireless charging technology, and in particular to a charging control method, electronic device, and wireless charging system. Background Technology

[0002] Wireless charging technology (WCT) uses conductive media such as electric fields, magnetic fields, microwaves, or lasers to achieve wireless transmission of electrical energy. Due to its advantages such as no wire restrictions and no plugging and unplugging, it is being used more and more widely in electronic devices.

[0003] To improve charging efficiency, wireless charging devices typically incorporate multiple series- or parallel DC-DC buck converters between the rectifier circuit and the battery. These converters reduce the rectifier's output voltage to the battery's charging voltage, thus preventing low voltage conversion efficiency caused by excessive voltage differences across a single buck converter. However, using multiple buck converters increases the cost of the device. Summary of the Invention

[0004] This application provides a charging control method, an electronic device, and a wireless charging system, which solve the problem of increased device costs caused by setting up multiple DC buck circuits in wireless charging devices while improving voltage conversion efficiency.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] One aspect of this application provides a charging control method applied to an electronic device. The electronic device includes a receiving coil, a wireless power receiver, a three-level buck circuit, a battery, and a receiving end controller. The wireless power receiver is electrically connected to the receiving coil, the three-level buck circuit is electrically connected to both the wireless power receiver and the battery, and the receiving end controller is electrically connected to both the wireless power receiver and the three-level buck circuit. Furthermore, the charging control method includes: the receiving end controller acquiring the battery voltage of the electronic device; the receiving end controller sending a first control signal to the wireless power receiver and a second control signal to the three-level buck circuit based on the acquired battery voltage; the wireless power receiver converting the alternating current induced by the receiving coil into direct current according to the first control signal, outputting a first voltage V1 to charge the battery in a first voltage mode; and the three-level buck circuit converting the voltage output by the wireless power receiver into direct current according to the second control signal and outputting it to the battery. The charging voltage received by the battery is the same as the acquired battery voltage. In this way, the electronic device provided in this application only requires a three-level buck circuit between the wireless power receiver and the battery. The receiver controller can control the output voltages of the wireless power receiver and the three-level buck circuit by outputting a first control signal to the wireless power receiver and inputting a second control signal to the three-level buck circuit, ensuring that the charging voltage received by the battery is the same as the acquired battery voltage. Furthermore, under the control of the receiver controller, the three-level buck circuit can function as a switched capacitor circuit during the constant current charging phase, thus achieving higher voltage conversion efficiency compared to traditional buck circuits. Moreover, compared to switched capacitor circuits, the receiver controller can perform closed-loop regulation of the three-level buck circuit, making its output voltage flexibly adjustable. Therefore, there is no need to include multiple DC buck circuits in the electronic device, thereby reducing costs.

[0007] Optionally, if the battery enters a constant current charging state, the wireless power receiver outputs a first voltage V1 according to a first control signal, including: the wireless power receiver adjusting the first voltage V1 according to the first control signal. The first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage. From Joule's law, the loss on the charging line is Q = I... 2 R. When the first voltage V1 output by the wireless power receiver is twice the battery voltage, the current in the charging circuit can be effectively reduced, thereby reducing losses.

[0008] Optionally, the three-level buck circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first, second, third, and fourth switching transistor connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switching transistors, and the second terminal of the flying capacitor is electrically connected between the third and fourth switching transistors. The first terminal of the first switching transistor is electrically connected to the wireless power receiver, and the second terminal of the fourth switching transistor is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switching transistor, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switching transistors. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switching transistors. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are half a cycle out of phase, the waveforms of the PWM signals input to the control terminals of the first and fourth switching transistors are opposite, and the waveforms of the PWM signals input to the control terminals of the second and third switching transistors are opposite. With the above structure, the three-level buck converter can operate in an open-loop state under the control of the receiver controller. The technical effects of the switching state are the same as described above, and will not be repeated here.

[0009] Optionally, before the three-level buck circuit reduces the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the first voltage V1 is twice the battery voltage, then the receiver controller sets the duty cycle D of the second control signal to D = 0.5. In this case, the three-level buck circuit operates in an open-loop state, and the three-level buck circuit can be equivalent to a switched capacitor circuit. Furthermore, as mentioned above, the wireless power receiver in the front stage of the three-level buck circuit, under the control of the receiver controller, can finely adjust the output voltage according to the change of the input voltage of the wireless power receiver, thus reducing the voltage difference between the first and second terminals of the inductor. In this way, the voltage difference across the inductor can be kept approximately constant, reducing the fluctuation of the output voltage. In addition, since the voltage difference is small, an inductor with a smaller inductance value is selected to reduce the ripple of the output current of the three-level buck circuit, improve the stability of battery charging, and reduce the heat loss of low-power electronic devices. Furthermore, since the inductance value of the aforementioned inductor is relatively small, the voltage conversion efficiency of the three-level buck circuit provided in this application embodiment is higher than that of a conventional buck circuit.

[0010] Optionally, in the three-level buck circuit, the voltage difference ΔV between the voltage at the first terminal of the inductor and the voltage at the second terminal of the inductor satisfies: 0V < ΔV ≤ 5V. When the voltage difference ΔV between the first terminal of the inductor and the voltage at the second terminal of the inductor is greater than 5V, the ripple of the output current of the three-level buck circuit is large, which is not conducive to improving the stability of battery charging.

[0011] Optionally, before the three-level buck circuit reduces the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is greater than 2:1, then the receiver controller sets the duty cycle D of the second control signal to D < 0.5. In this way, when the electronic device is placed on the wireless charging transmitter, which serves as a charging base, and the centers of the transmitting coil and the receiving coil are not perfectly aligned but have a certain offset, the receiver controller will determine that the ratio of the first voltage V1 to the battery voltage will be greater than 2:1. At this time, the receiver controller can finely adjust the output voltage of the three-level buck circuit, that is, set the duty cycle D of the PWM signal input to the control terminals of the first and second switching transistors in the three-level buck circuit so that D < 0.5, thereby making the charging voltage received by the battery close to the battery voltage obtained by the receiver control.

[0012] Optionally, before the three-level buck circuit reduces the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is less than 2:1, the receiver controller sets the duty cycle D of the second control signal to D > 0.5. In this way, when the electronic device is placed on the wireless charging transmitter, which serves as a charging base, and the centers of the transmitting and receiving coils are not perfectly aligned but have a certain offset, if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage will be less than 2:1, the output voltage of the three-level buck circuit can be finely adjusted by the receiver controller. That is, the duty cycle D of the PWM signal input to the control terminals of the first and second switching transistors in the three-level buck circuit is set to D > 0.5, thereby making the charging voltage received by the battery close to the battery voltage obtained by the receiver control.

[0013] Optionally, if the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a first preset current, after the wireless power receiver outputs a first voltage V1, and before the three-level buck circuit reduces the output voltage of the wireless power receiver, the method further includes: the wireless power receiver sending a second mode request to the wireless charging transmitter, and outputting a second voltage V2 according to a first control signal to charge the battery in a second voltage mode, where V1 > V2. Wherein, the first preset current is greater than or equal to the virtual load activation current threshold I of the wireless power receiver. th And the first preset current and the virtual load start-up current threshold I th The difference is within the first preset range, thus making the first preset current slightly greater than or equal to the virtual load turn-on current threshold I of the wireless power receiver. th For example, the first preset range can be 0mA to 200mA. Thus, when charging the battery using a first voltage V1, for example, V1 = 9V, when the battery's charging power drops to 0.9W, the virtual load inside the wireless power receiver will connect to the wireless charging system. However, when switching to a second voltage V2, for example, V2 = 5V, when the battery's charging power drops to 0.9W, the charging current will suddenly increase and exceed the virtual load activation current threshold I because the charging power has not changed instantaneously. th (For example, 100mA) prevents the virtual load from being turned on temporarily. Next, the charging current continues to decrease until it drops again to the virtual load activation current threshold I. th (For example, 100mA) Only then will the virtual load inside the wireless power receiver connect to the wireless charging system. As can be seen from the above, in this embodiment, when the battery charging current decreases to slightly greater than or equal to the virtual load activation current threshold I... th By switching from high-power charging to low-power charging, the access time of the virtual load can be delayed, thereby delaying the access time of the virtual load inside the wireless power receiver to the wireless charging system. This reduces the duration of the virtual load access to the wireless charging system, thereby reducing heat loss caused by the virtual load and slowing down the temperature rise of the positive electrode.

[0014] Optionally, if the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a second preset current, before the three-level buck circuit reduces the output voltage of the wireless power receiver after the wireless power receiver outputs a first voltage V1, the method further includes: the receiver controller controlling the output voltage of the wireless power receiver to gradually decrease from the first voltage V1 to the second voltage V2, so that the output current of the wireless power receiver remains at the second preset current until the wireless power receiver outputs the second voltage V2. The wireless power receiver outputs the second voltage V2 to charge the battery in a second voltage mode, where V1 > V2. The second preset current is greater than the virtual load start-up current threshold I of the wireless power receiver. th And the second preset current is equal to the virtual load start-up current threshold I. th The difference is within the second preset range, thus making the second preset current slightly greater than the virtual load turn-on current threshold I of the wireless power receiver. th For example, the second preset range can be 10mA to 200mA. As mentioned above, this second preset current is slightly greater than the virtual load activation current threshold I. th In this case, if the receiver controller detects that the current output by the wireless power receiver has decreased to the aforementioned second preset current, the receiver controller can control the current output by the wireless power receiver to remain unchanged and above the virtual load activation current threshold I. th The wireless power receiver continues in this state until it outputs the second voltage V2 (e.g., V2 = 5V). Next, the output current of the wireless power receiver gradually decreases until it reaches the virtual load turn-on current threshold I. th Only when the virtual load inside the wireless power receiver is connected to the wireless charging system will the connection time of the virtual load be reduced, thereby reducing heat loss caused by the virtual load and slowing down the temperature rise of the positive electrode.

[0015] Optionally, the receiver controller controls the output voltage of the wireless power receiver to gradually decrease from a first voltage V1 to a second voltage V2, including: within one cycle of the PWM signal output by the receiver controller, the step adjustment voltage value of the wireless power receiver output voltage is between 15mV and 3V. When the step adjustment voltage value is less than 15mV, the value is too small, requiring high operational precision from the receiver controller, which is not conducive to simplifying the calculation process and reducing costs. When the step adjustment voltage value is greater than 3V, the value is too large, which reduces the accuracy of the receiver controller's closed-loop regulation of the wireless power receiver.

[0016] Optionally, the electronic device further includes: a fifth switching transistor; the first terminal of the fifth switching transistor is electrically connected to the second terminal of an inductor, the second terminal of the fifth switching transistor is electrically connected to a battery, and the control terminal of the fifth switching transistor is electrically connected to a receiver controller. The method further includes: if the receiver controller detects that the battery charge has reached a maximum charge threshold, the receiver controller controls the fifth switching transistor to be in a cut-off state. After the battery finishes charging, the receiver controller can control the fifth switching transistor to be in a cut-off state by inputting a control signal to the control terminal of the fifth switching transistor.

[0017] In another aspect of this application, an electronic device is provided. The electronic device includes a receiving coil, a battery, a wireless power receiver, a three-level step-down circuit, and a receiver controller. The receiver controller is used to acquire the battery voltage of the electronic device and send a first control signal and a second control signal based on the acquired battery voltage. The receiving coil is used to generate alternating current (AC). The wireless power receiver is electrically connected to the receiving coil. Based on the first control signal, the wireless power receiver converts the AC current induced by the receiving coil into direct current (DC), outputting a first voltage V1 to charge the battery in a first voltage mode. The three-level step-down circuit is electrically connected to the wireless power receiver and the battery. Based on the second control signal, the three-level step-down circuit converts the voltage output by the wireless power receiver into DC and outputs it to the battery. The charging voltage received by the battery is the same as the acquired battery voltage. This electronic device has the same technical effects as the charging control method provided in the foregoing embodiments, and will not be repeated here.

[0018] Optionally, if the battery enters a constant current charging state, the wireless power receiver is also used to adjust the first voltage V1 according to a first control signal; the first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage. From Joule's law, the loss on the charging line is Q = I... 2 R. When the first voltage V1 output by the wireless power receiver is twice the battery voltage, the current in the charging circuit can be effectively reduced, thereby reducing losses.

[0019] Optionally, the three-level buck circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first, second, third, and fourth switching transistor connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switching transistors, and the second terminal of the flying capacitor is electrically connected between the third and fourth switching transistors. The first terminal of the first switching transistor is electrically connected to the wireless power receiver, and the second terminal of the fourth switching transistor is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switching transistor, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switching transistors. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switching transistors. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are half a cycle out of phase, the waveforms of the PWM signals input to the control terminals of the first and fourth switching transistors are opposite, and the waveforms of the PWM signals input to the control terminals of the second and third switching transistors are opposite. With the above structure, the three-level buck converter can operate in an open-loop state under the control of the receiver controller. The technical effects of the switching state are the same as described above, and will not be repeated here.

[0020] Optionally, the receiver controller is further configured to set the duty cycle D of the second control signal to D = 0.5 if it is determined that the first voltage V1 is twice the battery voltage. The technical effect of setting the duty cycle D of the second control signal to D = 0.5 is the same as described above, and will not be repeated here.

[0021] Optionally, the receiver controller is further configured to set the duty cycle D of the second control signal to D < 0.5 if it is determined that the ratio of the first voltage V1 to the battery voltage is greater than 2:1. The technical effect of setting the duty cycle D of the second control signal to D < 0.5 is the same as described above and will not be repeated here.

[0022] Optionally, the receiver controller is further configured to set the duty cycle D of the second control signal to D > 0.5 if the ratio of the first voltage V1 to the battery voltage is determined to be less than 2:1. The technical effect of setting the duty cycle D of the second control signal to D > 0.5 is the same as described above and will not be repeated here.

[0023] Optionally, if the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a first preset current, the wireless power receiver is also used to send a second mode request to the wireless charging transmitter and, according to the first control signal, output a second voltage V2 to charge the battery in a second voltage mode, where V1 > V2. The first preset current is greater than or equal to the virtual load activation current threshold I of the wireless power receiver.th And the first preset current and the virtual load start-up current threshold I th The difference is within a first preset range. This first preset range can be 0mA to 200mA. The control process and technical effect of reducing the voltage received by the wireless power receiver when the output current of the wireless power receiver decreases to the first preset current to delay the access time of the virtual load are the same as described above, and will not be repeated here.

[0024] Optionally, if the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a second preset current, the receiver controller is further configured to control the output voltage of the wireless power receiver to gradually decrease from the first voltage V1 to the second voltage V2, so that the output current of the wireless power receiver remains at the second preset current until the wireless power receiver outputs the second voltage V2; the wireless power receiver is also configured to output the second voltage V2 to charge the battery in a second voltage mode, where V1 > V2. The second preset current is greater than the virtual load activation current threshold I of the wireless power receiver. th And the second preset current is equal to the virtual load start-up current threshold I. th The difference is within a second preset range, which can be 10mA to 200mA. The control process and technical effect of delaying the access time of the virtual load by gradually reducing the output voltage of the wireless power receiver are the same as described above, and will not be repeated here.

[0025] Another aspect of this application provides a wireless charging system. This wireless charging system includes a wireless charging transmitter and the electronic device described above. The wireless charging transmitter includes a wireless power transmitter, a transmitting coil, and a transmitter controller. The wireless power transmitter converts received direct current (DC) into alternating current (AC). The transmitting coil is electrically connected to the wireless power transmitter and generates an alternating magnetic field based on the received AC and transmits it to the receiving coil. The transmitter controller is electrically connected to the wireless power transmitter and controls the output voltage and output current of the wireless power transmitter. This wireless charging system has the same technical effects as the electronic device provided in the foregoing embodiments, and will not be repeated here. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a wireless charging system provided in an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of another wireless charging system provided in an embodiment of this application;

[0028] Figure 3A This is a schematic diagram of another wireless charging system provided in an embodiment of this application;

[0029] Figure 3Bfor Figure 3A A schematic diagram of a structure for the TX coil and RX coil in the middle section;

[0030] Figure 4A This is a schematic diagram of another wireless charging system provided in an embodiment of this application;

[0031] Figure 4B for Figure 4A The control terminals of each transistor in the three-level step-down circuit are connected to the MCU. RX A schematic diagram of the electrical connection;

[0032] Figure 5 MCU provided for embodiments of this application RX A schematic diagram of a PWM signal input to the control terminals of each transistor in a three-level buck converter circuit;

[0033] Figure 6A MCU provided for embodiments of this application RX A flowchart illustrating the process of controlling a three-level step-down circuit;

[0034] Figure 6B for Figure 6A The equivalent circuit diagram;

[0035] Figure 7A MCU provided for embodiments of this application RX Another process flow diagram for controlling a three-level step-down circuit;

[0036] Figure 7B for Figure 7A The equivalent circuit diagram;

[0037] Figure 8 MCU provided for embodiments of this application RX A schematic diagram of another PWM signal input to the control terminals of each transistor in a three-level buck circuit;

[0038] Figure 9 MCU provided for embodiments of this application RX A schematic diagram of another PWM signal input to the control terminals of each transistor in a three-level buck circuit;

[0039] Figure 10A A flowchart of a control method for a wireless charging system provided in an embodiment of this application;

[0040] Figure 10B A flowchart illustrating another control method for the wireless charging system provided in this application embodiment;

[0041] Figure 11A A schematic diagram of the battery charging stage provided in an embodiment of this application;

[0042] Figure 11B for Figure 4A A schematic diagram of the voltage across the inductor;

[0043] Figure 12 This is a schematic diagram of another wireless charging system provided in an embodiment of this application;

[0044] Figure 13 Another schematic diagram of the battery charging stage provided in the embodiments of this application;

[0045] Figure 14 A flowchart illustrating another control method for the wireless charging system provided in this application embodiment;

[0046] Figure 15 This is another schematic diagram of the battery charging stage provided in an embodiment of this application.

[0047] Figure label:

[0048] 01-Wireless charging system; 02-Wireless charging receiver circuit; 10-Electronic device; 100-Battery; 101-RX coil; 102-RX IC; 103-Three-level buck circuit; 104-MCU RX 20-Wireless charging transmitter; 201-TX coil; 202-TXIC; 203-MCU TX ; 204 - Adapter; 205 - Boost circuit. Detailed Implementation

[0049] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0050] In the following text, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. The term "multiple" refers to two or more.

[0051] Furthermore, in this application, directional terms such as "upper" and "lower" may be defined relative to the orientation in which the components are schematically placed in the accompanying drawings. It should be understood that these directional terms can be relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation in which the components are placed in the accompanying drawings.

[0052] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "electrical connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium.

[0053] This application provides an embodiment of, as follows: Figure 1 The wireless charging system 01 shown may include an electronic device 10 and a wireless charging transmitter 20. The electronic device 10 may include a tablet computer, a laptop (e.g., an ultra-thin or portable model), a mobile phone, a wireless charging electric vehicle, a wireless charging small household appliance (e.g., a soymilk maker, a robot vacuum cleaner), or any other electronic product with wireless charging functionality. This application does not impose any special limitations on the specific form of the electronic device 10. The wireless charging transmitter 20 may be a wireless charging dock.

[0054] The electronic device 10 and the wireless charging transmitter 20 can communicate wirelessly via in-band communication, such as amplitude shift keying (ASK) modulation. Alternatively, the electronic device 10 and the wireless charging transmitter 20 can communicate wirelessly via out-of-band communication, such as Bluetooth, wireless-fidelity (WiFi), Zigbee, radio frequency identification (RFID), long-range (Lora) wireless technology, and near-field communication (NFC) technology.

[0055] The electronic device 10 provided in this application embodiment, such as Figure 1 As shown, the device may include a battery 100, a receive (RX) coil 101, and a wireless charging receiver circuit 02 electrically connected to the battery 100 and the receive coil 101. The wireless charging receiver circuit 02 may include a wireless power receiver 102, a three-level buck circuit 103, and a receiver controller 104. The wireless charging receiver circuit 02 may be integrated into a single chip. Furthermore, the wireless charging transmitter 20 may include a transmit (TX) coil 201, a wireless power transmitter 202, and a transmitter controller 203.

[0056] In some embodiments of this application, the receiver controller 104 and the transmitter controller 203 described above can be microcontroller units (MCUs). For ease of explanation, the receiver controller 104 will be referred to simply as an MCU in the accompanying drawings and the following description. RX 104. The transmitter controller 203 is referred to as MCU for short. TX 203. The wireless power receiver 102 is referred to as RX IC102, the wireless power transmitter 202 is referred to as TX IC202, the transmitting coil 201 is referred to as TX coil 201, and the receiving coil 101 is referred to as RX coil 101.

[0057] like Figure 1 As shown, MCU TX 203 is electrically connected to TX IC202, which is the MCU. TX 203 is used to control the output voltage and output current of TX IC202. TX IC202 is used to convert received DC power into AC power. In some embodiments of this application, such as... Figure 2 As shown, the wireless charging system 01 may further include an adapter 204, and the wireless charging transmitter 20 may further include a boost circuit 205 electrically connected to the adapter 204. The adapter 204 can be used to convert AC power output from an AC power source into DC power, for example, converting 220V AC power into 5V DC power. The boost circuit 205 may also be electrically connected to the TXIC 202, and the boost circuit 205 is used to boost the voltage output from the adapter 204, for example, boosting the 5V voltage to 9V before outputting it to the TXIC 202.

[0058] For example, when the battery 100 in the electronic device 10 needs to be charged in a first voltage mode (i.e., high-voltage mode charging), the RX IC 102 in the electronic device 10 can send a first mode request to the TX IC 202 in the wireless charging transmitter 20 via in-band or out-of-band communication. The TX IC 202 can then, based on the first mode request, send a first mode request via the MCU. TX203 controls the boost circuit 205 to convert the 5V voltage output from the adapter 204 to 9V and provide it to the TX IC 202. The TX coil 201 can generate an alternating magnetic field from the AC power from the TX IC 202 and transmit it to the RX coil 101 in the electronic device 10. The RX coil 101 can receive the alternating magnetic field from the TX coil 201 and induce AC power. At this time, the RX IC 102 can convert the AC power induced by the RX coil 101 into AC power and output a first voltage V1 (e.g., V1 = 9V) to achieve charging of the battery 100 in a first voltage mode. For example, the TX coil 201 and RX coil 101 described above can be as follows: Figure 3B The circular coil shown.

[0059] Furthermore, when the battery 100 in the electronic device 10 needs to be charged using a second voltage mode (i.e., low-voltage mode charging), the RX IC 102 in the electronic device 10 can send a second mode request to the TX IC 202 in the wireless charging transmitter 20. Based on this second mode request, the TX IC 202 can directly supply the 5V voltage output from the adapter 204 to the TX IC 202 without passing through the boost circuit 205. The TX coil 201 generates an alternating magnetic field from the AC power from the TX IC 202 and transmits it to the RX coil 101. The RX coil 101 receives the alternating magnetic field from the TX coil 201 and induces AC power. At this time, the RX IC 102 can convert the AC power induced by the RX coil 101 into AC power and output a second voltage V2 (e.g., V2 = 5V) to achieve second voltage mode charging of the battery 100.

[0060] Alternatively, in other embodiments of this application, the wireless charging transmitter 20 may also include, Figure 3A The adapter 204 is shown. This adapter 204 is electrically connected to the TX IC 202. In this case, when the TX IC 202 receives the aforementioned first mode request and second mode request, the output voltage of the adapter 204 can be adjusted under the control of the TX IC 202. For example, when charging the battery 100 in the electronic device 10 using the second voltage mode (i.e., low-voltage mode charging), under the control of the TX IC 202, the adapter 204 can convert the received 220V AC power into 5V DC power and provide it to the TX IC 202. Alternatively, when charging the electronic device 10 using the first voltage mode (i.e., high-voltage mode charging), under the control of the TX IC 202, the adapter 204 can convert the received 220V AC power into 9V DC power and provide it to the TX IC 202. In this way, it is unnecessary to include the aforementioned boost circuit 205 in the wireless charging transmitter 20 (e.g., ...). Figure 2As shown in the figure, this simplifies the circuit structure and reduces power loss in the charging path of the wireless charging system 01.

[0061] For example, the TX IC202 described above can be a full-bridge or half-bridge circuit. The TX IC202 can include multiple switching transistors, such as metal-oxide-semiconductor (MOS) field-effect transistors. The control terminal of the aforementioned switching transistors, such as the gate (g), can be connected to the MCU. TX 203 electrical connection. In this case, the MCU TX 203 can control the switching frequency and duty cycle of the MOSFET by sending a pulse width modulation (PWM) signal to the control terminal of the aforementioned switching transistor, thereby controlling the input-output voltage ratio of the TX IC202 and achieving fine-tuning of the TX IC202's output voltage. Taking an N-type switching transistor, where a high-level input to its control terminal puts it in the on state and a low-level input puts it in the off state, as an example, when the MCU... TX The duty cycle of the PWM signal provided by 203 to the control terminal of the switching transistor in TX IC202 is proportional to the output voltage of TX IC202, and the frequency of the PWM signal is inversely proportional to the output voltage of TX IC202.

[0062] Based on this, such as Figure 3A As shown, the wireless charging transmitter 20 may further include a matching capacitor C2 connected in series with the TX coil 201. This matching capacitor C2 and the TX coil 201 form a transmitter resonant network. The transmitter resonant network can convert the square wave signal output by the TX IC 202 into a sine wave, and the TX coil 201 can generate an alternating magnetic field based on the alternating current from the TX IC 202 and transmit it to the RX coil 101 in the electronic device 10. Furthermore, the electronic device 10 may also include a matching capacitor C1 connected in series with the RX coil 101. This matching capacitor C1 and the RX coil 101 form a receiver resonant network. The receiver resonant network can convert the sine wave into a square wave signal.

[0063] In addition, the RX IC102 is also compatible with MCUs RX 104 electrical connection, this MCU RX 104 can control the output voltage of RX IC102 to perform fine-grained closed-loop regulation of RX IC102 (closed-loop regulation means that the output changes with the input). For example, the RX IC102 mentioned above can be a full-bridge or half-bridge circuit, and it can include multiple switching transistors, such as MOSFETs. The control terminals of these switching transistors can be connected to the MCU. RX 104 electrical connection. In this case, the MCURX 104 can control the switching frequency and duty cycle of the MOSFET by inputting a first control signal, such as a PWM signal, to the control terminal of the aforementioned switching transistor, thereby controlling the input-output voltage ratio of RX IC102 and achieving fine-tuning of the RX IC102 output voltage. Similarly, assuming the aforementioned switching transistor is an N-type switching transistor, which is in the on state when the control terminal inputs a high level and in the off state when the input is low, when the MCU... RX The duty cycle of the PWM signal provided by 104 to the control terminal of the switching transistor in RX IC102 is proportional to the output voltage of RX IC102, and the frequency of the PWM signal is inversely proportional to the output voltage of RX IC102.

[0064] In addition, in MCU RX Under the control of 104, the three-level buck circuit 103 can convert the voltage output by RX IC 102 into DC-DC voltage to reduce it to a suitable voltage for supplying to battery 100. In the embodiments of this application, the above-mentioned three-level buck circuit 103 can be used as follows: Figure 4A The following is shown: Flying capacitor C fly Input capacitor C in Inductor L, Output capacitor C o And the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 connected in series.

[0065] Any one of the aforementioned first switch Q1, second switch Q2, third switch Q3, and fourth switch Q4 can be a MOSFET. Taking an N-type MOSFET as an example, the MOSFET can include a first terminal, such as the drain (d), a second terminal, such as the source (s), and a control terminal g. Therefore, the series connection of the first switch Q1, second switch Q2, third switch Q3, and fourth switch Q4 means that the source (s) of the first switch Q1 is electrically connected to the drain (d) of the second switch Q2, the source (s) of the second switch Q2 is electrically connected to the drain (d) of the third switch Q3, and the source (s) of the third switch Q3 is electrically connected to the drain (d) of the fourth switch Q4. When the aforementioned MOSFET is a P-type MOSFET, the first terminal of the MOSFET can be the source (s), and the second terminal can be the drain (d). For ease of explanation, the following description uses an N-type MOSFET as an example.

[0066] In addition, such as Figure 4A As shown, the aforementioned flying capacitor C fly The first terminal a1 is electrically connected between the first switch Q1 and the second switch Q2, and the flying capacitor C flyThe second terminal a2 is electrically connected between the third switch Q3 and the fourth switch Q4. The first terminal of the first switch Q1, for example, the drain d, is electrically connected to RX IC102, and the second terminal of the fourth switch Q4, for example, the source s, is grounded (GND). Input capacitor C in The first terminal a3 is electrically connected to the first terminal, such as the drain d, of the first switching transistor Q1, and the input capacitor C in The second terminal a4 is grounded. The first terminal b1 of inductor L is electrically connected between the second switch Q2 and the third switch Q3. Output capacitor C o The first terminal a5 is electrically connected to the second terminal b2 of the inductor L, and the output capacitor C o The second terminal is grounded. Furthermore, the positive terminal of battery 100 (indicated by "+") is connected to the output capacitor C. o The first terminal a5 is electrically connected, and the negative terminal of battery 100 (represented by "﹣") is grounded.

[0067] The control terminals of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, for example, the gate g... Figure 4B As shown, all are related to the MCU RX 104 electrical connection. This MCU RX 104 can provide second control signals with adjustable duty cycle D, such as PWM signals, to the control terminals of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, respectively, thereby enabling control via the MCU. RX 104 controls the on and off durations of each switching transistor, thereby achieving fine-tuning of the output voltage of the three-level buck circuit 103.

[0068] In this case, the first switch Q1 and the fourth switch Q4 can be a pair of complementary transistors. The MCU... RX The PWM signals provided by 104 to the control terminals g of the first switch Q1 and the fourth switch Q4 have opposite waveform directions. Furthermore, the second switch Q2 and the third switch Q3 can be a pair of complementary transistors. In this case, the MCU... RX The PWM signals provided by 104 to the control terminals g of the second switch Q2 and the third switch Q3 have opposite waveform directions. The working principle of the three-level buck circuit 103 is explained below.

[0069] For example, such as Figure 5 As shown, MCU RXThe duty cycle D of the PWM signals provided to the control terminals g of the first switch Q1 (acting as the main switch) and the second switch Q2 (acting as the secondary switch) both satisfy D = 0.5. The PWM signal received by the control terminal g of the first switch Q1 is half a cycle out of phase with the PWM signal received by the control terminal g of the second switch Q2. At this time, the waveforms of the first switch Q1 and the third switch Q3 (acting as a freewheeling diode) are the same, and the waveforms of the second switch Q2 and the fourth switch Q4 (acting as a freewheeling diode) are the same. Furthermore, within one cycle T, the conduction time of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 is T / 2.

[0070] In this case, such as Figure 5 As shown, in the first half of the cycle (T / 2), the MCU RX When the PWM signal input to the control terminal g of the first switch Q1 and the control terminal of the third switch Q3 is high, the first switch Q1 and the third switch Q3 are turned on. MCU RX When the PWM signals input to the control terminals g of the second switch Q2 and Q4 of the fourth switch Q4 are low, the second switch Q2 and the fourth switch Q4 are turned off (indicated by "×" in the diagram). At this time, as Figure 6A As shown, the input capacitor C in First switching transistor Q1, flying capacitor C fly The third switch Q3, inductor L, and output capacitor C o This forms a current loop, allowing RX IC102 (such as...) Figure 4A The input current I supplied to the three-level buck circuit 103 (as shown) is... in The flying capacitor C can be connected through the above current loop. fly It charges the inductor L. For example... Figure 5 As shown, the current I flowing through inductor L in the first half of the cycle (T / 2) is... L Gradually increase.

[0071] Based on this Figure 6A The equivalent circuit structure of the circuit shown is as follows Figure 6B As shown, it can be seen that the flying capacitor C fly With output capacitor C o Series connection. Therefore, after the above charging process is completed, the flying capacitor C fly Voltage V across the terminals fly Output capacitor C o Voltage V across the terminals o and input capacitor C in Voltage V across the terminals in The following formula (1) applies between them.

[0072] V in=V fly +V o (1)

[0073] In addition, such as Figure 5 As shown, in the second half of the cycle (T / 2), the MCU RX When the PWM signal input to the control terminal g of the first switch Q1 and the control terminal of the third switch Q3 is low, the first switch Q1 and the third switch Q3 are turned off. (MCU) RX When the PWM signal input to the control terminal g of the second switch Q2 and the control terminal of the fourth switch Q4 is high, the second switch Q2 and the fourth switch Q4 are turned on. At this time, as... Figure 7A As shown, the flying capacitor C fly The second switch Q2, inductor L, and output capacitor C o The fourth switch Q4 forms a current loop, causing the flying capacitor C to... fly Discharge current I o Discharge can occur through the aforementioned current loop. For example... Figure 5 As shown, the current I flowing through inductor L in the second half of the cycle (T / 2) L Gradually decrease.

[0074] Based on this Figure 7A The equivalent circuit structure of the circuit shown is as follows Figure 7B As shown, it can be seen that the flying capacitor C fly With output capacitor C o Parallel connection. Therefore, after the above discharge process is completed, the flying capacitor C fly Voltage V across the terminals fly The voltage V across the output capacitor Co o The following formula applies between them:

[0075] V fly =V o (2)

[0076] In this case, when formula (2) is substituted into formula (1), V can be obtained. o =V in / 2. In this way, the ratio of the output voltage to the input voltage of the three-level buck circuit 103 is 1:2.

[0077] Or, for example, such as Figure 8 As shown, MCU RXThe duty cycle D of the PWM signals provided to the control terminals g of the first switch Q1 and the second switch Q2 (which act as the main control transistors) both satisfy 0 < D < 0.5. The PWM signal received by the control terminal g of the first switch Q1 is out of phase with the PWM signal received by the control terminal g of the second switch Q2 by half a cycle. At this time, the waveforms of the first switch Q1 and the fourth switch Q4 are opposite, and the waveforms of the second switch Q2 and the third switch Q3 are opposite. Furthermore, within one cycle T, the conduction time of the first switch Q1 and the second switch Q2 is less than T / 2, at which time the output voltage V of the three-level buck circuit 103 is... o Satisfy: 0≤V o <V in / 2.

[0078] Or, for example, such as Figure 9 As shown, MCU RX The duty cycle D of the PWM signals provided by 104 to the control terminals g of the first switch Q1 and the second switch Q2 both satisfy 0.5 < D ≤ 1. The PWM signal received by the control terminal g of the first switch Q1 is out of phase with the PWM signal received by the control terminal g of the second switch Q2 by half a cycle. At this time, the waveforms of the first switch Q1 and the fourth switch Q4 are opposite, and the waveforms of the second switch Q2 and the third switch Q3 are opposite. In addition, within one cycle T, the conduction time of the first switch Q1 and the second switch Q2 is greater than T / 2, at which time the output voltage V of the three-level buck circuit 103 is... o Satisfy: V in / 2<V o ≤V in .

[0079] In summary, with Figure 4A Taking the wireless charging system 01 shown as an example, when the wireless charging transmitter 20 in the wireless charging system 01 charges the electronic device 10, the adapter 204 can convert 220V AC power into DC power. The magnitude of the DC power output by the adapter 204 can vary depending on the charging power requirements of the battery 100. (MCU) RX 104 can send the charging power requirement of battery 100 to TX IC202 via in-band or out-of-band communication using RX IC102, so that TX IC202 can control the magnitude of DC voltage output by adapter 204.

[0080] Next, TX IC202 converts the received DC power into AC power. TX coil 201 receives this AC power and induces an alternating magnetic field, which is then transmitted to RX coil 101 in electronic device 10. RX coil 101 generates DC power based on the alternating magnetic field emitted from TX coil 201. Next, in the MCU...RX Under the control of the first control signal output by 104, RX IC102 can convert the AC current induced by RX coil 101 into DC current and provide it to the three-level buck circuit 103. MCU RX 104 can output the aforementioned second control signal, such as a PWM signal, to the control terminals g of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 in the three-level buck circuit 103, respectively, so that the three-level buck circuit 103 converts the voltage output by RXIC102 into the battery voltage V. bat It provides power to battery 100 to charge battery 100.

[0081] The following combinations are as follows Figure 4A The wireless charging system 01 shown illustrates the charging process of the battery 100.

[0082] Example 1

[0083] The control method in this embodiment is as follows: Figure 10A As shown, it may include S101 to S109.

[0084] S101. Detect whether battery 100 has entered constant current (CC) charging state.

[0085] For example, such as Figure 4A It can be seen that during the charging process of battery 100, the MCU in electronic device 10... RX 104 is electrically connected to battery 100, and this MCU RX 104 can execute S101 as described above. In the MCU RX 104 During the execution of S101 above, a voltage threshold value can be set, such as a first voltage threshold V. th1 In addition, MCU RX A fuel gauge can be set in 104, which can measure the battery voltage V of battery 100. bat By collecting data, the battery voltage V of battery 100 can be determined. bat Has the first voltage threshold V been reached? th1 When the battery voltage V of battery 100 bat Reaching the first voltage threshold V th1 At that time, the battery 100 enters as... Figure 11A The constant current (CC) charging state is shown. For example, the first voltage threshold V. th1 It can be around 3.5V. If the MCU... RX 104 detected the battery voltage V of battery 100. bat Reaching the first voltage threshold V th1 Then execute S102 as follows.

[0086] S102, Send the first mode request.

[0087] When executing S101, if the MCU in electronic device 10 RX 104 Detects the battery voltage V of battery 100 bat Reaching the first voltage threshold V th1 The RX IC202 can communicate with... via in-band or out-of-band communication. Figure 4A The TX IC202 in the wireless charging transmitter 20 shown sends a first mode request.

[0088] S103. Increase the output voltage according to the first mode.

[0089] In this case, TX IC202 can control adapter 204 to directly output a larger voltage, such as 9V, based on the received first mode request. Alternatively, when the wireless charging transmitter 20 includes... Figure 2 When the boost circuit 205 is shown, the TXIC 202 can control the boost circuit 205 to increase the smaller voltage output by the adapter 204, for example, from 5V to 9V, according to the received first mode request. Next, the TX IC 202 converts the received voltage into alternating current and transmits it to the TX coil 201, causing the TX coil 201 to generate an alternating magnetic field.

[0090] S104 and RX IC102 output a first voltage V1 to charge the battery 100 in a first voltage mode.

[0091] The RX coil 101 induces the aforementioned alternating magnetic field and outputs alternating current to the RX IC 102. At this time, the voltage received by the RX IC 102 can be 9V. Furthermore, the MCU... RX 104 can supply the battery voltage V of battery 100. bat Data is collected. In this case, the MCU... RX 104 can be based on V bat Output the first control signal to RX IC102. RX IC102 can then adjust the signal according to the MCU's output. RX The first control signal output by 104 converts the alternating current generated by the RX coil 101 into direct current and outputs a first voltage V1 to charge the battery 100 in a first voltage mode.

[0092] During the charging process described above, according to Joule's law, the loss on the RX coil 101 is Q = I. 2During the CC charging phase, with the charging power remaining constant (e.g., 2W), when the AC voltage amplitude received by RX IC102 increases from 5V to 9V, the current in RX coil 101 decreases, thereby reducing the loss Q in RX coil 101, for example, by approximately 150mW. This effectively reduces the heat generation of low-power electronic devices 10 with relatively high internal coil impedance, such as smartwatches and headphones, during high-power charging.

[0093] In addition, battery 100 enters as Figure 11A During the CC charging phase shown, the current (I) output by RX IC102 is as follows: Figure 11A As shown, the voltage can remain constant within a certain range (represented by a horizontal straight line in the figure). At this time, the battery voltage V of battery 100... bat It will be determined by the first voltage threshold V th1 (For example, V) th1 =3.5V) gradually increases until the battery voltage V bat Reaching the second voltage threshold V th2 (For example, V) th2 =4.25V), the CC charging phase ends. This second voltage threshold V th2 The threshold value of the battery voltage when the battery 100 finishes the above CC charging stage and enters the constant voltage (CV) charging stage.

[0094] Based on this, in order to further reduce line losses, during the aforementioned CC charging phase, the MCU... RX The first control signal output by 104 can be used to instruct RX IC102 to adjust the aforementioned first voltage V1 to the battery voltage V. bat Twice that. As can be seen from the above, due to the battery voltage V of battery 100... bat During the CC charging phase described above, the first voltage threshold V can be used. th1 (For example, V) th1 =3.5V) rises to the second voltage threshold V th2 (For example, V) th2 =4.25V). Therefore, during the process of RX IC102 adjusting the first voltage V1 according to the aforementioned first control signal to achieve charging of battery 100 in the first voltage mode, since the first voltage V1 output by RX IC102 can be the battery voltage V bat It is about twice that of the CC charging stage, so the first voltage V1 output by RX IC102 can be around 7 to 9V.

[0095] In summary, MCU RX104 The output voltage of RX IC102 can be controlled by the first control signal mentioned above, so as to perform fine closed-loop regulation of RX IC102, so that the output voltage of RX IC102 can reach the battery voltage V. bat It is about twice as high as that used to charge the battery 100 at high voltage, reducing losses in the charging circuit.

[0096] In addition, MCU RX 104 can also be based on the obtained battery voltage V bat The second control signal is output to the three-level buck circuit 103, enabling the three-level buck circuit 103 to step down the output voltage of the RX IC 102 according to the second control signal. This allows for closed-loop regulation of the three-level buck circuit 103, ensuring that the charging voltage received by the battery 100 is consistent with the battery voltage V. bat For example, the charging voltage received by battery 100 is close to the battery voltage V. bat The difference between them can be in the range of 0 to 500 mA.

[0097] It should be noted that, in this embodiment of the application, the charging voltage received by the battery 100 can be related to the MCU. RX The battery voltage V obtained from 104 bat "Same" can mean that the values ​​are exactly the same, or that the voltage difference between the two is within a small range, such as 0 to 500mA.

[0098] Example, MCU RX The battery voltage V obtained from 104 bat When the voltage is around 4V, RX IC102 can adjust the first voltage V1 according to the first control signal mentioned above, so that the first voltage V1 is around 8V (the battery voltage V). bat For example, twice the DC voltage (e.g., 4V) is used to charge battery 100 at high voltage. Additionally, the MCU... RX 104 can also control the three-level buck circuit 103 to step down the input voltage using the second control signal, applying a voltage of approximately 4V to the battery 100 to charge it, so that the charging voltage received by the battery 100 is similar to that of the MCU. RX The battery voltage V obtained from 104 bat same.

[0099] Based on this, before the three-level buck circuit 103 reduces the output voltage of the RX IC 102 according to the second control signal, the charging method of the electronic device 10 may further include: if the MCU RX 104. Determine if the first voltage V1 output by RX IC102 is the battery voltage V. bat If it is twice that of the MCU, thenRX 104 can set the duty cycle D of the second control signal sent to the three-level buck circuit 103 to D = 0.5. Example: MCU RX The battery voltage V obtained from 104 bat The voltage is approximately 4V, and the first voltage V1 output by RX IC102 is approximately 8V. Under these circumstances... Figure 12 MCU in RX 104 can input a second control signal to the control terminal g of the first switch Q1 and the control terminal g of the second switch Q2. For example, the duty cycle D of the PWM signal described above satisfies the following conditions: Figure 5 The D = 0.5 shown is used to make the output voltage of the three-level buck circuit 103 approximately 4V, so that the charging voltage received by the battery 100 is similar to the battery voltage V. bat Approaching. Furthermore, since battery 100 is still in the CC charging phase, the battery voltage V... bat It has not yet risen to the second voltage threshold V th2 (For example, V) th2 =4.25V), therefore the output voltage of the three-level buck circuit is less than the second voltage threshold V of the battery. th2 .

[0100] In addition, as mentioned above, MCU RX The PWM signals input to the control terminals g of the first switch Q1 and the second switch Q2 are half a cycle out of phase. The waveforms of the PWM signals input to the control terminals g of the first switch Q1 and the fourth switch Q4 are opposite, and the waveforms of the PWM signals input to the control terminals g of the second switch Q2 and the third switch Q3 are opposite. The following describes the MCU... RX The PWM signals provided by 104 to each switch in the three-level buck circuit 103 all meet the above conditions, and will not be elaborated further.

[0101] In this case, the three-level buck circuit 103 operates in an open-loop state (open-loop state means that the output voltage of the three-level buck circuit 103 is always half of the input voltage of the three-level buck circuit 103, i.e., half of the first voltage V1 mentioned above). The three-level buck circuit 103 can be equivalent to a switched capacitor circuit (SC). Furthermore, as mentioned above, the RX IC 102 preceding the three-level buck circuit 103 in the MCU... RX Under the control of IC104, the output voltage can be finely adjusted according to the change of the input voltage of RX IC102. Therefore, the first terminal b1 and the second terminal b2 of inductor L (e.g. Figure 12The voltage difference ΔV between the two (as shown) satisfies: 0V<ΔV≤5V.

[0102] In this way, the voltage difference ΔV(V) across the inductor L can be reduced. b1 -V b2 )like Figure 11B As shown, the output voltage is in a nearly constant state, reducing fluctuations. Furthermore, since the voltage difference ΔV is small, an inductor L with a smaller inductance value is selected to reduce the ripple of the output current of the three-level buck circuit 103, improving the stability of the wireless charging receiver circuit 02 charging the battery 100 and reducing heat loss in the low-power electronic device 10. Moreover, because the inductance value of the aforementioned inductor L is small, the voltage conversion efficiency of the three-level buck circuit 103 provided in this embodiment is higher than that of a conventional buck circuit.

[0103] Furthermore, in some embodiments of this application, such as Figure 12 As shown, the wireless charging receiver circuit 02 described above may further include a fifth switch Q5. The first terminal of the fifth switch Q5, for example, the drain d, is electrically connected to the second terminal b2 of the inductor L; the second terminal of the fifth switch Q5, for example, the source s, is electrically connected to the positive terminal ("+") of the battery 100; and the control terminal g of the fifth switch Q5 is connected to the MCU. RX 104 electrical connection. In this case, when battery 100 is charging, the MCU... RX 104 can control the fifth switch Q5 to be in the on state by inputting a control signal to the control terminal g of the fifth switch Q5. For example, if the MCU RX When 104 detects that the battery 100 has reached the maximum power threshold, that is, when the power is 100%, RX IC102 can input a control signal to the control terminal g of the fifth switch Q5 to control the fifth switch Q5 to be in the off state.

[0104] Alternatively, in some other embodiments of this application, when the electronic device 10 is placed on the wireless charging transmitter 20, which serves as a charging dock, Figure 12 The centers of the TX coil 201 and RX coil 101 shown may not be perfectly aligned, but rather have a certain offset. In this case, when the center offset of the TX coil 201 and RX coil 101 is at its limit, during the aforementioned CC charging phase, even in the MCU... RX Under the control of 104, the RX IC102 is subjected to closed-loop regulation. The first voltage V1 output by the RX IC102 is related to the battery voltage V. bat The ratio cannot reach 2:1. In this case, if the MCU RX 104. Determine the relationship between the first voltage V1 output by RX IC102 and the battery voltage V. bat If the ratio is greater than 2:1, then the MCURX 104 can set the duty cycle D of the second control signal sent to the three-level buck circuit 103 to D < 0.5. For example, the first voltage V1 output by RX IC102 is approximately 9V, and the MCU... RX The battery voltage V obtained from 104 bat It is around 4V.

[0105] In this case, in order to make the output voltage of the three-level buck circuit 103 close to that of the MCU RX The battery voltage V obtained from 104 bat For example, around 4V, MCU RX 104 can input the duty cycle D of the PWM signal to the control terminal g of the first switch Q1 and the control terminal g of the second switch Q2, which satisfies the following condition: Figure 8 As shown, D < 0.5, resulting in an output voltage of approximately 4V for the three-level buck circuit 103, which is less than 0.5 × V1 (4.5V). This allows the charging voltage received by the battery 100 to be closer to the battery voltage V. bat Close. Furthermore, since battery 100 is still in the CC charging phase, the output voltage of the three-level buck circuit 103 is still less than the second voltage threshold V of battery 100. th2 .

[0106] Alternatively, in some other embodiments of this application, when Figure 12 When the center offset of the TX coil 201 and RX coil 101 shown is at its limit position, during the aforementioned CC charging phase, even in the MCU RX Under the control of 104, the RX IC102 is subjected to closed-loop regulation. The first voltage V1 output by the RX IC102 is related to the battery voltage V. bat The ratio cannot reach 2:1. In this case, if the MCU RX 104. Determine the relationship between the first voltage V1 output by RX IC102 and the battery voltage V. bat If the ratio is less than 2:1, then the MCU RX 104 can set the duty cycle D of the second control signal sent to the three-level buck circuit 103 to D > 0.5. For example, the first voltage V1 output by RXIC102 is 8V, and the MCU... RX The battery voltage V obtained from 104 bat It is around 4.2V.

[0107] In this case, in order to make the output voltage of the three-level buck circuit 103 close to that of the MCU RX The battery voltage V obtained from 104 bat For example, around 4.2V, MCU RX104 can input the duty cycle D of the PWM signal to the control terminal g of the first switch Q1 and the control terminal g of the second switch Q2, which satisfies the following condition: Figure 8 As shown, D > 0.5, resulting in an output voltage of approximately 4.2V for the three-level buck circuit 103, which is greater than 0.5 × V1 (4V). This allows the charging voltage received by the battery 100 to be equal to the battery voltage V. bat Close. Furthermore, since battery 100 is still in the CC charging phase, the output voltage of the three-level buck circuit 103 is still less than the second voltage threshold V of battery 100. th2 .

[0108] As can be seen from the above, during the CC charging phase, the following can be performed first: Figure 10B As shown in S111, it determines whether the first voltage V1 output by RX IC102 is the battery voltage V. bat Twice that. If the MCU RX 104 detected that the first voltage V1 output by RX IC102 is the battery voltage V. bat If the value is twice that of the circuit, then S112 is executed, and the three-level buck circuit 103 is in the aforementioned switching state.

[0109] If the center offset of TX coil 201 and RX coil 101 is at its limit position, then the MCU RX 104 detected that the first voltage V1 output by RXIC102 was no longer the battery voltage V. bat If the value is twice that of the circuit, then S113 and the three-level buck circuit 103 will be in the aforementioned closed-loop adjustment state. Specifically, this can be achieved through the MCU. RX 104 adjusts the duty cycle D of the PWM signal received by the control terminal g of each switch in the three-level buck circuit 103, thereby achieving fine closed-loop regulation of the output voltage of the three-level buck circuit 103. Compared with the existing SC circuit, the ratio of the output voltage to the input voltage of this three-level buck circuit 103 is no longer limited to 1:2, but can be adjusted more flexibly as needed.

[0110] In summary, in the electronic device 10 provided in this application embodiment, only a three-level buck circuit 103 needs to be set between the RX IC 102 and the battery 100. During the CC charging phase, this three-level buck circuit 103 can be equivalent to an SC circuit. Therefore, compared to a traditional buck circuit, even if the voltage difference between the output and input of the three-level buck circuit 103 is large, higher voltage conversion efficiency can be achieved. Furthermore, compared to an SC circuit, the MCU... RX104 can perform closed-loop regulation on the three-level buck circuit 103, making its output voltage flexibly adjustable. Therefore, there is no need to set up cascaded buck circuits and SC circuits in the electronic device 10, thereby simplifying the circuit structure and reducing costs.

[0111] As can be seen from the above, when the battery voltage V of battery 100... bat Reaching the second voltage threshold V th2 (For example, V) th2 =4.25V), CC charging stage ends. The battery enters the following state: Figure 11A The CV charging phase is shown. During this CV charging phase, the charging voltage V of battery 100 is... Figure 11A (Using solid lines in the middle) can remain constant within a certain range. Figure 11A (Using a straight line in the diagram), however, the charging current I provided by RX IC102 to battery 100 is... Figure 11A (The charging current is gradually reduced to the charging cutoff current of battery 100, indicated by a dotted line in the diagram). When the charging current received by battery 100 reaches the aforementioned charging cutoff current, battery 100 is in a fully charged state.

[0112] Since the charging current flowing into battery 100 gradually decreases during the aforementioned CV charging phase, to prevent the charging current from decreasing to the charging cutoff current, which would cause the output of RX IC102 to be approximately open-circuited and prevent electromagnetic induction between TX coil 201 and RX coil 101, when the charging current flowing into battery 100 decreases to the dummy load turn-on current threshold I... th For example, I th =100mA. An internal virtual load, such as a resistor, is incorporated into the RX IC102 circuit to prevent its output from being open-circuited. This improves the waveform quality of communication between the TX coil 201 and the RX coil 101, as well as system stability.

[0113] However, when the virtual load inside RX IC102 is connected to the wireless charging system 01, a loss of 100mW to 300mW is generated on the virtual load. The longer the virtual load is connected, the greater the loss generated by the virtual load. The above loss is consumed in the form of heat energy, which has a significant impact on the temperature rise of the chip and the overall temperature rise of the electronic device 10. Therefore, in order to reduce the heat loss caused by the connection of the virtual load, the control method provided in this application embodiment can execute the following S105 to S109.

[0114] It should be noted that the virtual load turn-on current threshold I varies depending on the type of RX IC102 chip. thThere are some differences, MCU RX 104 can enable the virtual load current threshold I for the aforementioned RX IC102 chip. th Perform identification.

[0115] S105. If the battery 100 is detected to enter a constant voltage (CV) charging state, then detect whether the output current of RX IC102 has decreased to the first preset current.

[0116] MCU in electronic device 10 RX As can be seen from the above, during the execution of S105, when the MCU... RX 104 detected the battery voltage V of battery 100. bat Reaching the second voltage threshold V th2 Then battery 100 enters a constant voltage (CV) charging state. Furthermore, if the MCU... RX If 104 detects that the output current of RX IC102 has not decreased to the first preset current, then continue to execute the above S104. If the output current of RX IC102 decreases to the first preset current, then execute the following S106.

[0117] Wherein, the first preset current is greater than or equal to the virtual load turn-on current threshold I of RX IC102. th And the first preset current and the virtual load start-up current threshold I th The difference ΔI is within the first preset range, thus making the first preset current slightly greater than or equal to the virtual load turn-on current threshold I of RX IC102. th The aforementioned first preset range can be 0mA to 200mA. For example, when the first preset current is compared with the virtual load turn-on current threshold I of RX IC102... th When the difference ΔI is 0, the first preset current and the aforementioned virtual load start-up current threshold I th They are equal. In this case, if the MCU RX 104 detected that the output current of RX IC102 dropped to the virtual load turn-on current threshold I of RX IC102. th Then execute S106 as follows.

[0118] Alternatively, when the virtual load threshold I of RX IC102 is activated from the first preset current and the current is equal to the current of the first preset current. th When the difference ΔI is greater than 0, the first preset current is slightly greater than the virtual load turn-on current threshold I of the aforementioned RX IC102. th In this case, if the MCU RX 104 detected that the output current of RX IC102 decreased to slightly above the virtual load turn-on current threshold I of RX IC102. thThen, execute S106 as follows. Furthermore, the value of ΔI cannot be too large; for example, if it is greater than 200mA, the current output by RX IC102 will be less than the virtual load turn-on current threshold I of RX IC102. th The difference is too large and does not meet the requirement of numerical similarity. For example, the current difference ΔI can be 0mA, 10mA, 20mA, 30mA, 50mA, 60mA, 100mA, 150mA, or 200mA, etc.

[0119] It should be noted that, for ease of explanation, the following description uses the first preset current and the aforementioned virtual load start-up current threshold I as the reference. th The explanation is based on the example of equality.

[0120] S106, Send the second mode request.

[0121] During the execution of S106, if the MCU in electronic device 10 RX 104 detected that the output current of RX IC102 dropped to the virtual load turn-on current threshold I of RX IC102. th The RX IC102 can communicate with the network via in-band or out-of-band communication. Figure 12 The TX IC202 shown sends a second power charging request.

[0122] S107. Reduce the output voltage according to the second power request.

[0123] In this case, the TX IC202 can control the adapter 204 to directly output a smaller voltage, such as 5V, to the TX IC202 based on the received second mode request, so as to reduce the output voltage of the wireless charging transmitter 20. Next, the TX IC202 converts the received second voltage V2 into alternating current and transmits it to the TX coil 201, so that the TX coil 201 generates an alternating magnetic field.

[0124] S108 and RX IC102 output a second voltage V2 to charge the battery 100 in a second voltage mode.

[0125] The RX coil 101 senses the aforementioned alternating magnetic field and outputs alternating current to the RX IC 102. At this time, the RX IC 102 can output a second voltage V2 (e.g., V2 = 5V) according to the aforementioned first control signal, thereby enabling the battery 100 to be charged in a second voltage mode. In this case, as described above, the MCU... RX 104 can be based on the obtained battery voltage V bat The output voltage of RX IC102 and the output voltage of the three-level buck circuit 103 are regulated in a closed loop.

[0126] For example, in MCURX Under the control of 104, RX IC102 can convert the AC voltage from RX coil 101, with a voltage amplitude equal to the second voltage V2, into a DC voltage. For example, the second voltage V2 of RX IC102 can be 5V. The three-level buck circuit 103 can step down the second voltage V2 output by RX IC102, for example, to the second voltage threshold V. th2 (V th2 =4.25V) and apply it to the battery 100 to charge it.

[0127] During this CV charging phase, the second voltage V2 output by the RX IC102 is related to the battery voltage V. bat The ratio is less than 2:1. For example, the second voltage V2 output by RX IC102 is approximately 5V, and the MCU... RX The battery voltage V obtained from 104 bat It is approximately 4.25V. Similarly, under these circumstances, in order for the charging voltage received by battery 100 to be close to that of the MCU... RX The battery voltage V obtained from 104 bat For example, around 4.2V, MCU RX 104 can input the duty cycle D of the PWM signal to the control terminal g of the first switch Q1 and the control terminal g of the second switch Q2, which satisfies the following condition: Figure 8 The value of D is greater than 0.5. This makes the output voltage of the three-level buck circuit 103 equal to or approximately equal to 4.25V, and applied to the battery 100.

[0128] The output current of S109 and RX IC102 gradually decreases to the virtual load turn-on current threshold I. th Virtual load balancer is enabled.

[0129] For example, the current threshold I is enabled with a virtual load. th Taking 100mA as an example, such as Figure 13 As shown, when RX IC102 outputs a first voltage V1, for example, V1 = 9V, to charge battery 100 in the first voltage mode, when the charging power of battery 100 decreases to Figure 13 At point A, when the power at point A is 0.9W, the virtual load inside RX IC102 is connected to the wireless charging system 01. However, when RX IC102 outputs a second voltage V2 at point A, for example, V2 = 5V, to charge battery 100 in the second voltage mode, the charging current suddenly increases and exceeds the virtual load activation current threshold I because the charging power has not changed instantaneously. th(For example, 100mA), so that the virtual load is not turned on at point A. Next, the charging current continues to decrease until it drops again to the virtual load turn-on current threshold I. th (For example, 100mA), that is, at point B (for example, power of 0.5W), the virtual load inside RXIC102 will be connected to the wireless charging system 01.

[0130] As can be seen from the above, in this embodiment of the application, when the charging current of battery 100 decreases to slightly greater than or equal to the virtual load start-up current threshold I... th (For example, at 100mA) By switching from high-power charging to low-power charging, the time for virtual load access can be delayed from point A to point B, thereby delaying the time for virtual load inside RX IC102 to access wireless charging system 01, reducing the duration of virtual load access to wireless charging system 01, thereby reducing heat loss caused by virtual load and slowing down the temperature rise of positive electrode.

[0131] Furthermore, during the execution of S101, if the MCU RX If S104 detects that battery 100 has not entered constant current charging, the above-mentioned S105 can also be executed to reduce heat loss caused by the activation of virtual load.

[0132] Example 2

[0133] The control method in this embodiment is as follows: Figure 14 As shown, it may include S201 to S208.

[0134] S201. Detect whether battery 100 has entered constant current (CC) charging state.

[0135] S202, Send the first mode request.

[0136] S203, Increase the output voltage according to the first mode request.

[0137] S204 and RC IC102 output a first voltage V1 to charge the battery 100 in a first voltage mode.

[0138] In this example, the method for battery 100 during the CC charging stage is the same as in Example 1. Therefore, the processes of S201, S202, S203, and S204 are the same as those of S101, S102, S103, and S104 described above, and will not be repeated here. The execution processes of S205 to S206 are different from those in Example 1.

[0139] S205. If the battery 100 is detected to enter a constant voltage charging state, then detect whether the current output by RX IC102 has decreased to the second preset current.

[0140] Similarly, MCURX 104 During the execution of S205 above, the battery voltage V of battery 100 can be detected. bat Has the second voltage threshold V been reached? th2 If the second voltage threshold V is reached th2 Then battery 100 enters constant voltage charging state.

[0141] Furthermore, the second preset current is greater than the virtual load turn-on current threshold I of RX IC102. th And the second preset current is equal to the virtual load start-up current threshold I. th The difference ΔI is within the second preset range, thus making the second preset current slightly greater than the virtual load turn-on current threshold I of RX IC102. th For example, the second preset range can be within the range of 10mA to 200mA. When the above ΔI is less than 10mA, the value of ΔI is too small for the MCU. RX The high precision required for 104 calculations hinders the simplification of the calculation process and cost reduction. When ΔI is greater than 200mA, the value of ΔI is too large, and the current output by RX IC102 is too close to the virtual load turn-on current threshold I of RX IC102. th The difference is too large and does not meet the requirement of numerical similarity. For example, the current difference ΔI could be 10mA, 20mA, 30mA, 50mA, 60mA, 100mA, 150mA, or 200mA, etc. If the MCU... RX If 104 detects that the current output by RX IC102 has decreased to the aforementioned second preset current, then execute S206. If the MCU... RX If 104 detects that the current output by RX IC102 has not decreased to the second preset current, then S202 is executed.

[0142] The output voltage of S206 and RX IC102 is gradually reduced to keep the output current of RX IC102 constant.

[0143] When executing S205, if the MCU RX 104 detects that the current output of RX IC102 has decreased to the aforementioned second preset current. RX IC102 can then communicate with the relevant authorities via in-band or out-of-band communication. Figure 12 The TX IC202 shown continues to send the aforementioned first mode request. In this case, the TX IC202 can continue to control the adapter 204 to directly output a larger voltage, such as 9V. Alternatively, when the wireless charging transmitter 20 includes... Figure 2 When the boost circuit 205 is shown, the TX IC202 can be controlled by the MCU. TX203 continues to control the boost circuit 205 to boost the smaller voltage output by the adapter 204, for example, 5V, to 9V.

[0144] Next, TX IC202 converts the received first voltage V1 into alternating current and transmits it to TX coil 201, causing TX coil 201 to generate an alternating magnetic field. RX coil 101 senses this alternating magnetic field and outputs alternating current to RX IC102. In the MCU... RX Under the control of 104, the voltage output of RX IC102 can be gradually reduced from the first voltage V1 (e.g., V1 = 9V) to the second voltage V2 (e.g., V2 = 5V), while keeping the current output of RX IC102 constant and above the virtual load turn-on current threshold I. th The state continues until the RX IC102 outputs the aforementioned second voltage V2 (e.g., V2 = 5V).

[0145] Based on this, as can be seen from the above, it can be achieved through the MCU. RX 104 adjusts the duty cycle D of the PWM signal received by the control terminal g of each switch in the three-level buck circuit 103 to perform fine closed-loop regulation of the output voltage of the three-level buck circuit 103, so that the three-level buck circuit 103 can maintain a constant voltage at the input terminal of the battery 100 during the CV charging stage, thereby improving the charging stability.

[0146] In some embodiments of this application, in the MCU RX Under the control of 104, as the voltage output by RX IC102 gradually decreases from the first voltage V1 (e.g., V1 = 9V) to the second voltage V2 (e.g., V2 = 5V), the MCU... RX Within one cycle of the first control signal output by IC104, the step adjustment voltage value of the output voltage of RX IC102 can be between 15mV and 3V. When the step adjustment voltage value is less than 15mV, the value is too small, which is detrimental to the MCU. RX The high precision required for 104 operations hinders simplification of the calculation process and cost reduction. Furthermore, when the step voltage exceeds 3V, the aforementioned step voltage value becomes too large, potentially degrading the MCU's performance. RX 104. The accuracy of closed-loop regulation of RX IC102.

[0147] S207. Detect whether the output voltage of RX IC102 has dropped to the second voltage V2.

[0148] Specifically, the MCU in electronic device 10 RX104 can detect whether RX IC102 outputs the second voltage V2 to determine whether the output voltage of RX IC102 has dropped to the second voltage V2. If the MCU... RX If 104 detects that RX IC102 outputs the second voltage V2, then execute S208 as described above. If the MCU... RX If 104 detects that RX IC102 is not outputting the second voltage V2, then continue to execute the above S206.

[0149] S208. Charge battery 100 in the second voltage mode. The output current of RX IC102 gradually decreases to the virtual load start-up current threshold I. th Virtual load balancer is enabled.

[0150] During the execution of S208, the battery 100 enters the CV stage. Therefore, the RX IC102 can communicate with the TXIC202 through the internally configured processor, so that the voltage output by the transmitting coil 201 can meet the requirement of keeping the output voltage of the RX IC102 constant.

[0151] Furthermore, since the output voltage of the RX IC102 has decreased to the second voltage V2 (e.g., V2 = 5V) during the execution of S208, the second voltage V2 output by the RX IC102 is related to the battery voltage V. bat The ratio is less than 2:1. For example, the second voltage V2 output by RX IC102 is 5V, and the MCU... RX The battery voltage V obtained from 104 bat It is 4.25V. As mentioned above, in this case, in order to make the output voltage of the three-level buck circuit 103 close to that of the MCU... RX The battery voltage V obtained from 104 bat For example, 4.2V, MCU RX 104 can input the duty cycle D of the PWM signal to the control terminal g of the first switch Q1 and the control terminal g of the second switch Q2, which satisfies the following condition: Figure 8 The value of D is greater than 0.5. This makes the output voltage of the three-level buck circuit 103 equal to or approximately equal to 4.25V, which is applied to the battery 100 to charge the battery 100.

[0152] As can be seen from the above, the second preset current is slightly greater than the virtual load start-up current threshold I. th In this case, if the MCU RX 104 detects that the current output by RX IC102 has decreased to the aforementioned second preset current, for example... Figure 15 At point A as shown, MCU RX 104 can control the output current of RX IC102 to remain constant and greater than the virtual load turn-on current threshold I.th The state continues until the RX IC102 outputs the second voltage V2 (for example, V2 = 5V), which is at point B.

[0153] Next, the output current of RX IC102 gradually decreases until it reaches the virtual load turn-on current threshold I. th At point b1, the virtual load inside RX IC102 will connect to the wireless charging system 01. If the above-described method of gradually reducing the output voltage of RX IC102 is not used, when battery 100 enters the constant voltage stage, its charging current will reach the virtual load activation current threshold I at point a1. th Therefore, at point a1, the virtual load inside RX IC102 will be connected to the wireless charging system 01. Thus, in this embodiment, the time of virtual load connection can be delayed from point a1 to point b1, thereby reducing the duration of virtual load connection to the wireless charging system 01, thereby reducing heat loss caused by virtual load and slowing down the temperature rise of the positive electrode.

[0154] Furthermore, relative to Figure 13 In the corresponding example one, in this example, when the charging power of battery 100 switches from point A to point B, such as Figure 15 As shown, the charging current received by battery 100 can remain constant and always stay above the virtual load start-up current threshold I. th This state can avoid losses caused by sudden changes in charging current.

[0155] The above 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 scope of the technology 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 the claims.

Claims

1. A charging control method, applied to electronic devices, characterized in that, The electronic device includes a receiving coil, a wireless power receiver, a three-level step-down circuit, a battery, and a receiver controller; the wireless power receiver is electrically connected to the receiving coil, the three-level step-down circuit is electrically connected to the wireless power receiver and the battery, and the receiver controller is electrically connected to the wireless power receiver and the three-level step-down circuit. The charging control method includes: The receiver controller acquires the battery voltage of the electronic device; The receiver controller sends a first control signal to the wireless power receiver based on the acquired battery voltage, and sends a second control signal to the three-level step-down circuit; The wireless power receiver sends a first mode request to the wireless charging transmitter and, according to the first control signal, converts the alternating current induced by the receiving coil into direct current and outputs a first voltage V1 to charge the battery in a first voltage mode. The three-level step-down circuit reduces the output voltage of the wireless power receiver by the second control signal and outputs it to the battery; wherein the charging voltage received by the battery is the same as the battery voltage. If the battery enters a constant voltage charging state, and the output current of the wireless power receiver decreases to a first preset current, and after the wireless power receiver outputs a first voltage V1, before the three-level step-down circuit steps down the output voltage of the wireless power receiver, the method further includes: The wireless power receiver sends a second mode request to the wireless charging transmitter and outputs a second voltage V2 according to the first control signal to charge the battery in a second voltage mode, where V1 > V2. Wherein, the first preset current is greater than or equal to the virtual load turn-on current threshold I of the wireless power receiver. th And the first preset current and the virtual load turn-on current threshold I th The difference is within the first preset range.

2. The charging control method according to claim 1, characterized in that, If the battery enters a constant current charging state, the wireless power receiver outputs a first voltage V1 according to the first control signal, including: the wireless power receiver adjusting the first voltage V1 according to the first control signal; the first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage.

3. The charging control method according to claim 2, characterized in that, The three-level step-down circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first switch, a second switch, a third switch, and a fourth switch connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switches, and the second terminal of the flying capacitor is electrically connected between the third and fourth switches. The first terminal of the first switch is electrically connected to the wireless power receiver, and the second terminal of the fourth switch is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switch, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switches. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switches. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are phase-different by half a cycle, the PWM signals input to the control terminals of the first and fourth switching transistors have opposite waveforms, and the PWM signals input to the control terminals of the second and third switching transistors have opposite waveforms.

4. The charging control method according to claim 3, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the first voltage V1 is twice the battery voltage, then the receiver controller sets the duty cycle D of the second control signal to D=0.

5.

5. The charging control method according to claim 4, characterized in that, In the three-level step-down circuit, the voltage difference ΔV between the voltage at the first terminal of the inductor and the voltage at the second terminal of the inductor satisfies: 0V < ΔV ≤ 5V.

6. The charging control method according to claim 3, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is greater than 2:1, then the receiver controller sets the duty cycle D of the second control signal to D < 0.

5.

7. The charging control method according to claim 3, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is less than 2:1, then the receiver controller sets the duty cycle D of the second control signal to D > 0.

5.

8. The charging control method according to claim 3, characterized in that, The electronic device further includes: a fifth switching transistor; the first terminal of the fifth switching transistor is electrically connected to the second terminal of the inductor, the second terminal of the fifth switching transistor is electrically connected to the battery, and the control terminal of the fifth switching transistor is electrically connected to the receiver controller; The method further includes: if the receiver controller detects that the battery power has reached the maximum power threshold, the receiver controller controls the fifth switch to be in the off state.

9. A charging control method, applied to electronic devices, characterized in that, The electronic device includes a receiving coil, a wireless power receiver, a three-level step-down circuit, a battery, and a receiver controller; the wireless power receiver is electrically connected to the receiving coil, the three-level step-down circuit is electrically connected to the wireless power receiver and the battery, and the receiver controller is electrically connected to the wireless power receiver and the three-level step-down circuit. The charging control method includes: The receiver controller acquires the battery voltage of the electronic device; The receiver controller sends a first control signal to the wireless power receiver based on the acquired battery voltage, and sends a second control signal to the three-level step-down circuit; The wireless power receiver sends a first mode request to the wireless charging transmitter and, according to the first control signal, converts the alternating current induced by the receiving coil into direct current and outputs a first voltage V1 to charge the battery in a first voltage mode. The three-level step-down circuit reduces the output voltage of the wireless power receiver by the second control signal and outputs it to the battery; wherein the charging voltage received by the battery is the same as the battery voltage. If the battery enters a constant voltage charging state, and the output current of the wireless power receiver decreases to a second preset current, after the wireless power receiver outputs a first voltage V1, and before the three-level step-down circuit steps down the output voltage of the wireless power receiver, the method further includes: The receiver controller controls the output voltage of the wireless power receiver to be gradually reduced from the first voltage V1 to the second voltage V2, so that the current output by the wireless power receiver remains at the second preset current until the wireless power receiver outputs the second voltage V2; The wireless power receiver outputs the second voltage V2 to charge the battery in a second voltage mode, where V1 > V2; Wherein, the second preset current is greater than the virtual load turn-on current threshold I of the wireless power receiver. th And the second preset current is equal to the virtual load turn-on current threshold I. th The difference is within the second range.

10. The charging control method according to claim 9, characterized in that, The receiver controller controls the output voltage of the wireless power receiver to be gradually reduced from the first voltage V1 to the second voltage V2, including: Within one cycle of the first control signal, the step adjustment voltage value of the output voltage of the wireless power receiver is between 15mV and 3V.

11. The charging control method according to claim 9, characterized in that, If the battery enters a constant current charging state, the wireless power receiver outputs a first voltage V1 according to the first control signal, including: the wireless power receiver adjusting the first voltage V1 according to the first control signal; the first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage.

12. The charging control method according to claim 11, characterized in that, The three-level step-down circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first switch, a second switch, a third switch, and a fourth switch connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switches, and the second terminal of the flying capacitor is electrically connected between the third and fourth switches. The first terminal of the first switch is electrically connected to the wireless power receiver, and the second terminal of the fourth switch is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switch, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switches. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switches. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are phase-different by half a cycle, the PWM signals input to the control terminals of the first and fourth switching transistors have opposite waveforms, and the PWM signals input to the control terminals of the second and third switching transistors have opposite waveforms.

13. The charging control method according to claim 12, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the first voltage V1 is twice the battery voltage, then the receiver controller sets the duty cycle D of the second control signal to D=0.

5.

14. The charging control method according to claim 13, characterized in that, In the three-level step-down circuit, the voltage difference ΔV between the voltage at the first terminal of the inductor and the voltage at the second terminal of the inductor satisfies: 0V < ΔV ≤ 5V.

15. The charging control method according to claim 12, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is greater than 2:1, then the receiver controller sets the duty cycle D of the second control signal to D < 0.

5.

16. The charging control method according to claim 12, characterized in that, Before the three-level step-down circuit steps down the output voltage of the wireless power receiver according to the second control signal, the method further includes: if the receiver controller determines that the ratio of the first voltage V1 to the battery voltage is less than 2:1, then the receiver controller sets the duty cycle D of the second control signal to D > 0.

5.

17. The charging control method according to claim 12, characterized in that, The electronic device further includes: a fifth switching transistor; the first terminal of the fifth switching transistor is electrically connected to the second terminal of the inductor, the second terminal of the fifth switching transistor is electrically connected to the battery, and the control terminal of the fifth switching transistor is electrically connected to the receiver controller; The method further includes: if the receiver controller detects that the battery power has reached the maximum power threshold, the receiver controller controls the fifth switch to be in the off state.

18. An electronic device, characterized in that, The electronic device includes: A receiving coil is used to induce and generate alternating current; Battery; A receiver controller is used to acquire the battery voltage of the electronic device and send a first control signal and a second control signal based on the acquired battery voltage. A wireless power receiver, electrically connected to the receiving coil, is used to convert the alternating current induced by the receiving coil into direct current according to the first control signal, and output a first voltage V1 to charge the battery in a first voltage mode. A three-level step-down circuit, electrically connected to the wireless power receiver and the battery, is used to step down the voltage output by the wireless power receiver according to the second control signal and then output it to the battery; the charging voltage received by the battery is the same as the battery voltage. If the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a first preset current, the wireless power receiver is also used to send a second mode request to the wireless charging transmitter and output a second voltage V2 according to the first control signal to charge the battery in a second voltage mode, where V1 > V2. Wherein, the first preset current is greater than or equal to the virtual load turn-on current threshold I of the wireless power receiver. th And the first preset current and the virtual load turn-on current threshold I th The difference is within the first preset range.

19. The electronic device according to claim 18, characterized in that, If the battery enters a constant current charging state, the wireless power receiver is also used to adjust the first voltage V1 according to the first control signal; the first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage.

20. The electronic device according to claim 19, characterized in that, The three-level step-down circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first switch, a second switch, a third switch, and a fourth switch connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switches, and the second terminal of the flying capacitor is electrically connected between the third and fourth switches. The first terminal of the first switch is electrically connected to the wireless power receiver, and the second terminal of the fourth switch is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switch, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switches. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switches. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are phase-different by half a cycle, the PWM signals input to the control terminals of the first and fourth switching transistors have opposite waveforms, and the PWM signals input to the control terminals of the second and third switching transistors have opposite waveforms.

21. The electronic device according to claim 20, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D=0.5 if it is determined that the first voltage V1 is twice the battery voltage.

22. The electronic device according to claim 20, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D < 0.5 if it is determined that the ratio of the first voltage V1 to the battery voltage is greater than 2:

1.

23. The electronic device according to claim 20, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D > 0.5 if it is determined that the ratio of the first voltage V1 to the battery voltage is less than 2:

1.

24. An electronic device, characterized in that, The electronic device includes: A receiving coil is used to induce and generate alternating current; Battery; A receiver controller is used to acquire the battery voltage of the electronic device and send a first control signal and a second control signal based on the acquired battery voltage. A wireless power receiver, electrically connected to the receiving coil, is used to convert the alternating current induced by the receiving coil into direct current according to the first control signal, and output a first voltage V1 to charge the battery in a first voltage mode. A three-level step-down circuit, electrically connected to the wireless power receiver and the battery, is used to step down the voltage output by the wireless power receiver according to the second control signal and then output it to the battery; the charging voltage received by the battery is the same as the battery voltage. If the battery enters a constant voltage charging state and the output current of the wireless power receiver decreases to a second preset current, the receiver controller is further configured to control the output voltage of the wireless power receiver to gradually decrease from the first voltage V1 to the second voltage V2, so that the current output by the wireless power receiver remains at the second preset current until the wireless power receiver outputs the second voltage V2; the wireless power receiver is further configured to output the second voltage V2 to charge the battery in a second voltage mode, where V1 > V2; Wherein, the second preset current is greater than the virtual load turn-on current threshold I of the wireless power receiver. th And the second preset current is equal to the virtual load turn-on current threshold I. th The difference is within the second range.

25. The electronic device according to claim 24, characterized in that, If the battery enters a constant current charging state, the wireless power receiver is also used to adjust the first voltage V1 according to the first control signal; the first control signal is used to instruct the wireless power receiver to adjust the first voltage V1 to twice the battery voltage.

26. The electronic device according to claim 25, characterized in that, The three-level step-down circuit includes: a flying capacitor, an input capacitor, an inductor, an output capacitor, and a first switch, a second switch, a third switch, and a fourth switch connected in series. The first terminal of the flying capacitor is electrically connected between the first and second switches, and the second terminal of the flying capacitor is electrically connected between the third and fourth switches. The first terminal of the first switch is electrically connected to the wireless power receiver, and the second terminal of the fourth switch is grounded. The first terminal of the input capacitor is electrically connected to the first terminal of the first switch, and the second terminal of the input capacitor is grounded. The first terminal of the inductor is electrically connected between the second and third switches. The first terminal of the output capacitor is electrically connected to the second terminal of the inductor, and the second terminal of the output capacitor is grounded. The duty cycle of the second control signal is the duty cycle of the output pulse width modulation (PWM) signal input to the control terminals of the first and second switches. Specifically, the PWM signals input to the control terminals of the first and second switching transistors are phase-different by half a cycle, the PWM signals input to the control terminals of the first and fourth switching transistors have opposite waveforms, and the PWM signals input to the control terminals of the second and third switching transistors have opposite waveforms.

27. The electronic device according to claim 26, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D=0.5 if it is determined that the first voltage V1 is twice the battery voltage.

28. The electronic device according to claim 26, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D < 0.5 if it is determined that the ratio of the first voltage V1 to the battery voltage is greater than 2:

1.

29. The electronic device according to claim 26, characterized in that, The receiver controller is further configured to set the duty cycle D of the second control signal to D > 0.5 if it is determined that the ratio of the first voltage V1 to the battery voltage is less than 2:

1.

30. A wireless charging system, characterized in that, Includes a wireless charging transmitter and an electronic device as described in any one of claims 18-29; the wireless charging transmitter includes: A wireless power transmitter used to convert received direct current (DC) into alternating current (AC); A transmitting coil, electrically connected to the wireless power transmitter, is used to generate an alternating magnetic field based on the received alternating current and transmit it to the receiving coil; The transmitter controller is electrically connected to the wireless power transmitter and is used to control the output voltage and output current of the wireless power transmitter.

Images