A module capable of realizing wireless charging of two-section series lithium battery

Abstract

The utility model discloses a module can realize two section series connection lithium cell wireless charging, including the power input circuit of transmitting end, main control processing circuit and transmitting coil drive circuit, the wireless charge receiving rectifier filter communication sending circuit and two section lithium cell charging circuit of receiving end, the utility model discloses can realize two section series connection lithium cell's non -contact type charging, and the identification and the reminder of metal foreign matter, has overcome the security hidden danger of unstable existence of charging.

Description

Technical Field

[0001] This utility model relates to the field of wireless charging of lithium batteries, and in particular to a module that can realize wireless charging of two series-connected lithium batteries. Background Technology

[0002] Currently, some electronic products on the market that use two series-connected lithium batteries for power and require waterproofing still use waterproof charging connectors and physical contacts for charging. The following problems exist with charging these products: Waterproof charging connectors typically use waterproof gaskets for waterproofing, but poor assembly of the gaskets and contact surfaces can lead to water ingress during use. Furthermore, special operating environments can cause oxidation and corrosion of the metal contacts, resulting in unstable charging and potential safety hazards. Utility Model Content

[0003] The purpose of this invention is to provide a module that enables wireless charging of two series-connected lithium batteries, thereby solving the aforementioned technical problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A module for wireless charging of two series-connected lithium batteries includes a power input circuit, a main control processing circuit, and a transmitting coil driving circuit at the transmitting end, and a wireless charging receiving, rectification, filtering, communication and transmitting circuit and a charging circuit for the two lithium batteries at the receiving end.

[0006] In the power input circuit, connector J1 is connected to a DC 5V power supply. The positive terminal of the power supply is connected to fuse F1, and then from fuse F1 to one end of TVS diode D3. The other end of TVS diode D3 is connected to GND. Fuse F1 is connected to one end of resistor R16, and the other end of resistor R16 is connected to the energy absorption circuit composed of capacitor C14. After passing through the energy absorption circuit, the power supply is connected to the 5th, 6th, and 8th input pins of chip U2, and the other end is connected to resistor R5. The other end of resistor R5 is connected to the 1st, 2nd, 3rd, and 4th pins of chip U2, and then to capacitor C1. The power supply VCC is connected to the 16th pin of chip U1 and the 3rd pin of chip U3.

[0007] In the main control processing circuit, the power supply VCC is connected to one end of resistor R1, and the other end of resistor R1 is connected to resistor R2 to form a voltage divider signal FR. The voltage divider signal FR is connected to capacitor C11 and then to pin 10 of chip U1 for setting the coil drive frequency.

[0008] The power supply VCC is connected to one end of R7, and the other end of resistor R7 is connected to resistor R8 to form a voltage divider signal FOD. The voltage divider signal FOD is connected to capacitor C7 and then to pin 8 of chip U1, which is used to set the voltage divider signal FOD.

[0009] The power supply VCC is connected to resistor R9. The other end of R9 is connected to NTC thermistor R10 to form an NTC voltage divider signal. The NTC voltage divider signal is connected to capacitor C10 and then to pin 6 of chip U1 to detect the temperature of the transmitting coil. If the temperature is too high, the coil will shut down, thus providing over-temperature protection.

[0010] The power supply VCC is connected to capacitor C2 and then to pin 16 of chip U1 to supply power to chip U1.

[0011] The signal OPO output from pin 15 of chip U1 is connected to resistors R11 and R15. The other ends of resistors R11 and R15 are connected to capacitors C5 and C8 to form a decoding circuit. Capacitor C5 is connected to pin 11 IS of the main control chip U1, and capacitor C8 is connected to pin 12 CS of the main control chip U1.

[0012] The power supply VCC is connected to the positive terminal of indicator light D1. The negative terminal of indicator light D1 is connected to one end of resistor R3. The other end of resistor R3 is then connected to pin 7 of chip U1 to indicate the charging status. The power supply VCC is connected to the positive terminal of indicator light D2. The negative terminal of indicator light D2 is connected to one end of resistor R4. The other end of resistor R4 is then connected to pin 4 of chip U1 to indicate the fully charged status.

[0013] Pin 2 PWMP of chip U1 is connected to resistor R17 of the transmitter coil drive circuit to drive transistors Q1 and Q3. Pin 5 PWMN of chip U1 is connected to resistor R18 of the transmitter coil drive circuit to drive transistors Q2 and Q4. Pin 9 OPIN of chip U1 is connected to resistor R6 and capacitor C6 to process the voltage input signal of resistor R14.

[0014] In the transmitting coil driving circuit, the power supply VCC is connected to the collector of transistor Q1, the emitter of transistor Q1 is connected to the emitter of transistor Q3, and then connected to pin 2 of chip U3. The collector of transistor Q3 is connected to GND, and resistor R17 is connected to the base of transistors Q1 and Q3 and to resistor R13.

[0015] The power supply VCC is connected to the collector of transistor Q2 and resistor R12. The emitter of transistor Q2 is connected to the emitter of transistor Q4, and then to pin 4 of chip U3. The collector of transistor Q4 is connected to GND. Resistor R18 is connected to the base of Q2 and transistor Q4, as well as one end of resistor R12.

[0016] Pins 5, 6, 7, and 8 of MOSFET U3 are connected to one end of the transmitting coil L1 and the negative terminal of Schottky diode D4. The other end of the transmitting coil L1 is connected to capacitors C9, C12, C13, and C15, forming a series resonant circuit that converts electrical energy into an alternating magnetic field. The other ends of capacitors C9, C12, C13, and C15 are connected to pin 1 of MOSFET U3 and the positive terminal of Schottky diode D4, as well as to resistors R6 and R14.

[0017] The power supply VCC is connected to capacitors C3, C4, and C16, and then to pin 3 of MOSFET U3 to supply power to the MOSFET. Resistor R14 is used to detect the current. One end of resistor R14 is connected to resistor R6, and the other end of resistor R6 is connected to capacitor C6 and pin 9 of the main control chip U1 to detect and process the voltage signal.

[0018] In the wireless charging receiver rectification filter communication transmission circuit, one end of the receiving coil L1 is connected to capacitors C2, C3, C10, and C11, and the other end is connected to capacitors C12 and C1, as well as the cathode of Schottky diode D2 and the anode of Schottky diode D1. The AC voltage induced by the resonant circuit formed by the coil and capacitors is rectified into DC voltage by Schottky diode D1. Schottky diode D2 is a freewheeling diode.

[0019] The cathode of Schottky diode D1 is connected to one end of capacitors C4, C5, C6 and resistor R4. Capacitors C4, C5 and C6 are used to filter the rectified voltage VIN.

[0020] The other end of resistor R4 is connected to resistor R5 and the base of pin 1 of transistor Q4 to form a charging signal CHG. The collector of pin 3 of transistor Q4 is connected to pin 1 of chip U2 for charging judgment. The emitter of pin 2 of transistor Q4 is connected to GND.

[0021] The other end of capacitor C12 is connected to pin 3 of MOSFET Q3, pin 2 is connected to GND, and pin 1 is connected to resistor R3 and pin 6 of chip U2, forming a communication code transmission line. By controlling the conduction and cutoff of MOSFET, the resonant frequency of the receiving coil and capacitor is changed to realize the transmission of communication code.

[0022] Pin 5 of chip U2 is connected to capacitor C14 and pin 5 of chip U1 to supply power to chip U2. Pin 2 of chip U2 is connected to the other end of capacitor C14 and connected to GND. Pin 3 of chip U2 is connected to pin 8 of chip U1 for the determination of a full charge signal.

[0023] In the two-cell lithium battery charging circuit, the power supply VIN is connected to pin 6 of chip U1 and one end of resistor R1. The other end of resistor R1 is connected to pin 7 of chip U1, resistor R8, and the source of pin 2 of MOSFET Q2. The gate of pin 1 of MOSFET Q2 is connected to resistor R8 and pin 1 of chip U1. The drain of pin 3 of MOSFET Q2 is connected to inductor L2. The other end of inductor L2 is connected to the drain of pin 3 of MOSFET Q1 and the anode of Schottky diode D3. The gate of pin 1 of MOSFET Q1 is connected to pin 4 of chip U1. The source of pin 2 of MOSFET Q1 is connected to GND. Together, they form a boost circuit to charge the two series-connected lithium batteries.

[0024] Resistor R2 is an NTC resistor, with one end connected to pin 3 of chip U1 and the other end connected to GND. It is used to detect the temperature of the battery surface. When the temperature is too high, charging stops. Pin 2 of chip U1 is connected to capacitors C7 and C8 and the positive terminal of the battery. It is used to detect the battery voltage to realize trickle charging, constant current charging, and battery full charge determination. Pin 1 of chip U1 is connected to the gate of Q2. When the battery is full, MOSFET Q2 is turned off. Pin 8 of chip U1 is connected to pin 3 of chip U2 to output a battery full charge signal. Pin 5 of chip U1 is connected to pin 5 of chip U2 to supply power to chip U2. Pin 9 of chip U1 is connected to GND. Resistor R1 is a current sensing resistor, connected to pins 6 and 7 of chip U1, and is used to detect the input current of the inductor.

[0025] Preferably, the OVP chip U2 is model SA8210D, which has overvoltage and overcurrent protection to protect the back-end main control processing circuit and the transmitting coil drive circuit.

[0026] Preferably, the chip U1 is model JDS9122J.

[0027] Compared with the prior art, the present invention has the following advantages: the present invention can realize contactless charging of two series-connected lithium batteries, as well as the identification and reminder of metal foreign objects, overcoming the safety hazards caused by unstable charging. Attached Figure Description

[0028] Figure 1 This is a power input circuit diagram for the transmitter of this utility model;

[0029] Figure 2 This is the main control processing circuit diagram of this utility model;

[0030] Figure 3 This is a circuit diagram of the transmitting coil driving circuit of this utility model;

[0031] Figure 4 This is a circuit diagram of the wireless charging receiver, rectifier, filter, communication, and transmitter circuit of the receiving end of this utility model.

[0032] Figure 5 This is a circuit diagram of the charging circuit for the two lithium batteries of this utility model. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] A module for wireless charging of two series-connected lithium batteries includes a power input circuit, a main control processing circuit, and a transmitting coil driving circuit at the transmitting end, and a wireless charging receiving, rectification, filtering, communication and transmitting circuit and a charging circuit for the two lithium batteries at the receiving end.

[0035] In the power input circuit, connector J1 is connected to a DC 5V power supply. The positive terminal of the power supply is connected to fuse F1, and then from fuse F1 to one end of TVS diode D3. The other end of TVS diode D3 is connected to GND. Fuse F1 is connected to one end of resistor R16, and the other end of resistor R16 is connected to the energy absorption circuit composed of capacitor C14. After passing through the energy absorption circuit, the power supply is connected to the 5th, 6th, and 8th input pins of chip U2, and the other end is connected to resistor R5. The other end of resistor R5 is connected to the 1st, 2nd, 3rd, and 4th pins of chip U2, and then to capacitor C1. The power supply VCC is connected to the 16th pin of chip U1 and the 3rd pin of chip U3.

[0036] In the main control processing circuit, the power supply VCC is connected to one end of resistor R1, and the other end of resistor R1 is connected to resistor R2 to form a voltage divider signal FR. The voltage divider signal FR is connected to capacitor C11 and then to pin 10 of chip U1 for setting the coil drive frequency.

[0037] The power supply VCC is connected to one end of R7, and the other end of resistor R7 is connected to resistor R8 to form a voltage divider signal FOD. The voltage divider signal FOD is connected to capacitor C7 and then to pin 8 of chip U1, which is used to set the voltage divider signal FOD.

[0038] The power supply VCC is connected to resistor R9. The other end of R9 is connected to NTC thermistor R10 to form an NTC voltage divider signal. The NTC voltage divider signal is connected to capacitor C10 and then to pin 6 of chip U1 to detect the temperature of the transmitting coil. If the temperature is too high, the coil will shut down, thus providing over-temperature protection.

[0039] The power supply VCC is connected to capacitor C2 and then to pin 16 of chip U1 to supply power to chip U1.

[0040] The signal OPO output from pin 15 of chip U1 is connected to resistors R11 and R15. The other ends of resistors R11 and R15 are connected to capacitors C5 and C8 to form a decoding circuit. Capacitor C5 is connected to pin 11 IS of the main control chip U1, and capacitor C8 is connected to pin 12 CS of the main control chip U1.

[0041] The power supply VCC is connected to the positive terminal of indicator light D1. The negative terminal of indicator light D1 is connected to one end of resistor R3. The other end of resistor R3 is then connected to pin 7 of chip U1 to indicate the charging status. The power supply VCC is connected to the positive terminal of indicator light D2. The negative terminal of indicator light D2 is connected to one end of resistor R4. The other end of resistor R4 is then connected to pin 4 of chip U1 to indicate the fully charged status.

[0042] Pin 2 PWMP of chip U1 is connected to resistor R17 of the transmitter coil drive circuit to drive transistors Q1 and Q3. Pin 5 PWMN of chip U1 is connected to resistor R18 of the transmitter coil drive circuit to drive transistors Q2 and Q4. Pin 9 OPIN of chip U1 is connected to resistor R6 and capacitor C6 to process the voltage input signal of resistor R14.

[0043] In the transmitting coil driving circuit, the power supply VCC is connected to the collector of transistor Q1, the emitter of transistor Q1 is connected to the emitter of transistor Q3, and then connected to pin 2 of chip U3. The collector of transistor Q3 is connected to GND, and resistor R17 is connected to the base of transistors Q1 and Q3 and to resistor R13.

[0044] The power supply VCC is connected to the collector of transistor Q2 and resistor R12. The emitter of transistor Q2 is connected to the emitter of transistor Q4, and then to pin 4 of chip U3. The collector of transistor Q4 is connected to GND. Resistor R18 is connected to the base of Q2 and transistor Q4, as well as one end of resistor R12.

[0045] Pins 5, 6, 7, and 8 of MOSFET U3 are connected to one end of the transmitting coil L1 and the negative terminal of Schottky diode D4. The other end of the transmitting coil L1 is connected to capacitors C9, C12, C13, and C15, forming a series resonant circuit that converts electrical energy into an alternating magnetic field. The other ends of capacitors C9, C12, C13, and C15 are connected to pin 1 of MOSFET U3 and the positive terminal of Schottky diode D4, as well as to resistors R6 and R14.

[0046] The power supply VCC is connected to capacitors C3, C4, and C16, and then to pin 3 of MOSFET U3 to supply power to the MOSFET. Resistor R14 is used to detect the current. One end of resistor R14 is connected to resistor R6, and the other end of resistor R6 is connected to capacitor C6 and pin 9 of the main control chip U1 to detect and process the voltage signal.

[0047] In the wireless charging receiver rectification filter communication transmission circuit, one end of the receiving coil L1 is connected to capacitors C2, C3, C10, and C11, and the other end is connected to capacitors C12 and C1, as well as the cathode of Schottky diode D2 and the anode of Schottky diode D1. The AC voltage induced by the resonant circuit formed by the coil and capacitors is rectified into DC voltage by Schottky diode D1. Schottky diode D2 is a freewheeling diode.

[0048] The cathode of Schottky diode D1 is connected to one end of capacitors C4, C5, C6 and resistor R4. Capacitors C4, C5 and C6 are used to filter the rectified voltage VIN.

[0049] The other end of resistor R4 is connected to resistor R5 and the base of pin 1 of transistor Q4 to form a charging signal CHG. The collector of pin 3 of transistor Q4 is connected to pin 1 of chip U2 for charging judgment. The emitter of pin 2 of transistor Q4 is connected to GND.

[0050] The other end of capacitor C12 is connected to pin 3 of MOSFET Q3, pin 2 is connected to GND, and pin 1 is connected to resistor R3 and pin 6 of chip U2, forming a communication code transmission line. By controlling the conduction and cutoff of MOSFET, the resonant frequency of the receiving coil and capacitor is changed to realize the transmission of communication code.

[0051] Pin 5 of chip U2 is connected to capacitor C14 and pin 5 of chip U1 to supply power to chip U2. Pin 2 of chip U2 is connected to the other end of capacitor C14 and connected to GND. Pin 3 of chip U2 is connected to pin 8 of chip U1 for the determination of a full charge signal.

[0052] In the two-cell lithium battery charging circuit, the power supply VIN is connected to pin 6 of chip U1 and one end of resistor R1. The other end of resistor R1 is connected to pin 7 of chip U1, resistor R8, and the source of pin 2 of MOSFET Q2. The gate of pin 1 of MOSFET Q2 is connected to resistor R8 and pin 1 of chip U1. The drain of pin 3 of MOSFET Q2 is connected to inductor L2. The other end of inductor L2 is connected to the drain of pin 3 of MOSFET Q1 and the anode of Schottky diode D3. The gate of pin 1 of MOSFET Q1 is connected to pin 4 of chip U1. The source of pin 2 of MOSFET Q1 is connected to GND. Together, they form a boost circuit to charge the two series-connected lithium batteries.

[0053] Resistor R2 is an NTC resistor, one end connected to pin 3 of chip U1 and the other end connected to GND. It is used to detect the surface temperature of the battery. When the temperature is too high, charging stops. Pin 2 of chip U1 is connected to capacitors C7 and C8 and the positive terminal of the battery. It is used to detect the battery voltage to realize trickle charging, constant current charging, and battery full charge determination. Pin 1 of chip U1 is connected to the gate of Q2. When the battery is fully charged, MOSFET Q2 is turned off. Pin 8 of chip U1 is connected to pin 3 of chip U2 to output a battery full charge signal. Pin 5 of chip U1 is connected to pin 5 of chip U2 to power chip U2. Pin 9 of chip U1 is connected to GND. Resistor R1 is a current sensing resistor, connected to pins 6 and 7 of chip U1, used to detect the input current of the inductor. Chip U1 is model JDS9122J and chip U2 is model SA8210D, both OVP chips, with overvoltage and overcurrent protection to protect the back-end main control processing circuit and the transmitting coil drive circuit.

[0054] The above description is a preferred embodiment of the present utility model. For those skilled in the art, any changes, modifications, substitutions and variations made to the implementation methods without departing from the principles and spirit of the present utility model, based on the teachings of the present utility model, still fall within the protection scope of the present utility model.

Claims

1. A module for wireless charging of two series-connected lithium batteries, characterized in that, It includes a power input circuit, a main control processing circuit, and a transmitting coil drive circuit at the transmitting end; and a wireless charging receiving, rectification, filtering, communication, and transmitting circuit and a two-cell lithium battery charging circuit at the receiving end. In the power input circuit, connector J1 is connected to a DC 5V power supply. The positive terminal of the power supply is connected to fuse F1, and then from fuse F1 to one end of TVS diode D3. The other end of TVS diode D3 is connected to GND. Fuse F1 is connected to one end of resistor R16, and the other end of resistor R16 is connected to the energy absorption circuit composed of capacitor C14. After passing through the energy absorption circuit, the power supply is connected to the 5th, 6th, and 8th input pins of chip U2, and the other end is connected to resistor R5. The other end of resistor R5 is connected to the 1st, 2nd, 3rd, and 4th pins of chip U2, and then to capacitor C1. The power supply VCC is connected to the 16th pin of chip U1 and the 3rd pin of chip U3. In the main control processing circuit, the power supply VCC is connected to one end of resistor R1, and the other end of resistor R1 is connected to resistor R2 to form a voltage divider signal FR. The voltage divider signal FR is connected to capacitor C11 and then to pin 10 of chip U1. The power supply VCC is connected to one end of R7, and the other end of resistor R7 is connected to resistor R8 to form a voltage divider signal FOD. The voltage divider signal FOD is connected to capacitor C7 and then to pin 8 of chip U1, which is used to set the voltage divider signal FOD. The power supply VCC is connected to resistor R9, and the other end of R9 is connected to NTC thermistor R10 to form an NTC voltage divider signal. The NTC voltage divider signal is connected to capacitor C10 and then to pin 6 of chip U1. The power supply VCC is connected to capacitor C2 and then to pin 16 of chip U1 to supply power to chip U1. The signal OPO output from pin 15 of chip U1 is connected to resistors R11 and R15. The other ends of resistors R11 and R15 are connected to capacitors C5 and C8 to form a decoding circuit. Capacitor C5 is connected to pin 11 IS of the main control chip U1, and capacitor C8 is connected to pin 12 CS of the main control chip U1. The power supply VCC is connected to the positive terminal of indicator light D1. The negative terminal of indicator light D1 is connected to one end of resistor R3. The other end of resistor R3 is then connected to pin 7 of chip U1 to indicate the charging status. The power supply VCC is connected to the positive terminal of indicator light D2. The negative terminal of indicator light D2 is connected to one end of resistor R4. The other end of resistor R4 is then connected to pin 4 of chip U1. Pin 2 PWMP of chip U1 is connected to resistor R17 of the transmitter coil drive circuit to drive transistors Q1 and Q3. Pin 5 PWMN of chip U1 is connected to resistor R18 of the transmitter coil drive circuit to drive transistors Q2 and Q4. Pin 9 OPIN of chip U1 is connected to resistor R6 and capacitor C6 to process the voltage input signal of resistor R14. In the transmitting coil driving circuit, the power supply VCC is connected to the collector of transistor Q1, the emitter of transistor Q1 is connected to the emitter of transistor Q3, and then connected to pin 2 of chip U3. The collector of transistor Q3 is connected to GND, and resistor R17 is connected to the base of transistors Q1 and Q3 and to resistor R13. The power supply VCC is connected to the collector of transistor Q2 and resistor R12. The emitter of transistor Q2 is connected to the emitter of transistor Q4, and then to pin 4 of chip U3. The collector of transistor Q4 is connected to GND. Resistor R18 is connected to the base of Q2 and transistor Q4, as well as one end of resistor R12. Pins 5, 6, 7, and 8 of MOSFET U3 are connected to one end of the transmitting coil L1 and the negative terminal of Schottky diode D4. The other end of the transmitting coil L1 is connected to capacitors C9, C12, C13, and C15, forming a series resonant circuit that converts electrical energy into an alternating magnetic field. The other ends of capacitors C9, C12, C13, and C15 are connected to pin 1 of MOSFET U3 and the positive terminal of Schottky diode D4, as well as to resistors R6 and R14. The power supply VCC is connected to capacitors C3, C4, and C16, and then to pin 3 of MOSFET U3 to supply power to the MOSFET. Resistor R14 is used to detect the current. One end of resistor R14 is connected to resistor R6, and the other end of resistor R6 is connected to capacitor C6 and pin 9 of the main control chip U1. In the wireless charging receiver rectification filter communication transmission circuit, one end of the receiving coil L1 is connected to capacitors C2, C3, C10, and C11, and the other end is connected to capacitors C12 and C1, as well as the cathode of Schottky diode D2 and the anode of Schottky diode D1. The AC voltage induced by the resonant circuit formed by the coil and capacitors is rectified into DC voltage by Schottky diode D1. Schottky diode D2 is a freewheeling diode. The cathode of Schottky diode D1 is connected to one end of capacitors C4, C5, C6 and resistor R4. Capacitors C4, C5 and C6 are used to filter the rectified voltage VIN. The other end of resistor R4 is connected to resistor R5 and the base of pin 1 of transistor Q4 to form a charging signal CHG. The collector of pin 3 of transistor Q4 is connected to pin 1 of chip U2 for charging judgment. The emitter of pin 2 of transistor Q4 is connected to GND. The other end of capacitor C12 is connected to pin 3 of MOSFET Q3, pin 2 is connected to GND, and pin 1 is connected to resistor R3 and pin 6 of chip U2. Pin 5 of chip U2 is connected to capacitor C14 and pin 5 of chip U1 to supply power to chip U2. Pin 2 of chip U2 is connected to the other end of capacitor C14 and connected to GND. Pin 3 of chip U2 is connected to pin 8 of chip U1 for the determination of a full charge signal. In the two-cell lithium battery charging circuit, the power supply VIN is connected to pin 6 of chip U1 and one end of resistor R1. The other end of resistor R1 is connected to pin 7 of chip U1, resistor R8, and the source of pin 2 of MOSFET Q2. The gate of pin 1 of MOSFET Q2 is connected to resistor R8 and pin 1 of chip U1. The drain of pin 3 of MOSFET Q2 is connected to inductor L2. The other end of inductor L2 is connected to the drain of pin 3 of MOSFET Q1 and the anode of Schottky diode D3. The gate of pin 1 of MOSFET Q1 is connected to pin 4 of chip U1. The source of pin 2 of MOSFET Q1 is connected to GND. Together, they form a boost circuit to charge the two series-connected lithium batteries. Resistor R2 is an NTC resistor, with one end connected to pin 3 of chip U1 and the other end connected to GND. Pin 2 of chip U1 is connected to capacitors C7 and C8 and the positive terminal of the battery. Pin 1 of chip U1 is connected to the gate of Q2. When the battery is fully charged, MOSFET Q2 is turned off. Pin 8 of chip U1 is connected to pin 3 of chip U2. Pin 5 of chip U1 is connected to pin 5 of chip U2 to supply power to chip U2. Pin 9 of chip U1 is connected to GND. Resistor R1 is a current sensing resistor, connected to pins 6 and 7 of chip U1.

2. The module for wireless charging of two series-connected lithium batteries as described in claim 1, characterized in that, The chip U2 is an OVP chip with model number SA8210D.

3. A module for wireless charging of two series-connected lithium batteries as described in claim 1, characterized in that, The model number of chip U1 is JDS9122J.

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