Three-way intelligent battery charger

Abstract

The application discloses a three-way intelligent battery charger, comprising a Type-C input module, a fast charging protocol identification module, a main control single-chip microcomputer module, a Buck voltage reduction circuit, a Boost voltage increase circuit, a current sampling detection circuit, a voltage voltage division feedback circuit, an indicator lamp module and a lithium battery output port. The application integrates three independent Buck voltage reduction circuits and Boost voltage increase circuits, can simultaneously charge three 8.4V lithium batteries, realizes synchronous charging in multiple ways and does not interfere with each other, improves charging efficiency; moreover, the HUSB237 chip U5 can quickly identify the fast charging type, can be compatible with 5V ordinary charging heads and PD or QC9V fast charging power supplies, the main control single-chip microcomputer U2 can automatically switch the voltage increase and voltage reduction topologies, is suitable for most Type-C power supply devices on the market, and the set battery preheating activation mechanism can ladder type improve the charging current, avoids the damage of large current direct charging to the electric core of the power shortage battery, and prolongs the cycle life of the battery.

Description

Technical Field

[0001] This invention relates to the field of lithium battery charging equipment technology, specifically a three-channel intelligent battery charger. Background Technology

[0002] Lithium batteries are batteries that use lithium metal and lithium alloys as the negative electrode and employ a non-aqueous electrolyte solution. The lithium batteries commonly referred to in everyday life are mostly lithium-ion rechargeable batteries, which rely on the insertion and extraction of lithium ions between the positive and negative electrodes to achieve charging and discharging energy storage. Portable lithium battery charging devices are small, portable devices specifically designed to charge lithium-ion cells or lithium battery packs and provide external power. They are portable and compatible with various lithium battery products such as mobile phones, cameras, flashlights, power tools, and small energy storage lithium batteries. Currently, portable lithium battery charging devices have the following technical shortcomings: The charging channel is single, supporting only the charging of a single lithium battery. Charging multiple batteries requires multiple chargers, which takes up a lot of space and is costly. The charging mode is fixed, and it is not compatible with ordinary 5V charging heads and PD / QC fast charging 9V power supplies. It cannot automatically switch between boost and buck circuits, and has poor versatility. Without an input power adaptive protection mechanism, it is easy to damage the front-end Type-C charging head and power bank during high-power charging, thus damaging the power supply equipment. The lack of dynamic current sharing logic in multi-channel charging leads to large differences in current among the channels when multiple batteries are charged simultaneously, resulting in poor battery charging consistency and shortened battery life. The lack of a battery preheating and activation process means that direct high-current charging can easily damage depleted lithium batteries, and the full-charge recognition logic is simplistic, leading to a high risk of overcharging.

[0003] Furthermore, existing ordinary multi-channel chargers only use fixed constant current output and cannot automatically switch Buck / Boost topology according to input voltage. They also lack intelligent control functions such as fast charging protocol recognition, input current limiting, battery preheating, and multi-channel dynamic current sharing, which limits their application scenarios and results in insufficient charging safety and battery protection performance. Therefore, we propose a three-channel intelligent battery charger. Summary of the Invention

[0004] The purpose of this invention is to provide a three-channel intelligent battery charger to solve the problems that need to be addressed in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a three-channel intelligent battery charger, comprising a Type-C input module, a fast charging protocol identification module, a main control microcontroller module, a Buck step-down circuit, a Boost step-up circuit, a current sampling and detection circuit, a voltage divider feedback circuit, an indicator light module, and a lithium battery output port; The Type-C input module is used for power supply to the entire device; The fast charging protocol identification module is used to receive input signals from the Type-C input module and identify the fast charging type; The main control microcontroller module is electrically connected to the fast charging protocol identification module, the main control microcontroller module, three Buck step-down circuits, three Boost step-up circuits, current sampling and detection circuit, voltage divider feedback circuit, and three indicator light modules, and performs battery preheating, constant current and constant voltage charging, input power current limiting, multi-channel dynamic current sharing, full charge determination, and overvoltage and overcurrent protection. The main control microcontroller module outputs six PWM drive signals to drive the Buck step-down circuit and the Boost step-up circuit, and outputs three IO levels to drive the indicator light modules to operate. Both the Buck step-down circuit and the Boost step-up circuit are set to three channels, with the three sets of Buck step-down circuits and Boost step-up circuits corresponding to three independent lithium battery charging channels. The Buck step-down circuit only operates in 9V fast charging mode, stepping down the 9V bus voltage to 8.4V to charge the dual-cell lithium battery. The Boost circuit operates only in the 5V normal charging mode, boosting the 5V bus voltage to 8.4V to charge the lithium battery. The main control microcontroller module mutually excludes the switching of the Boost circuit and the Buck circuit, so they will not be turned on at the same time. The current sampling and detection circuit is set to three channels. Each channel outputs a high-precision sampling resistor in series with the negative terminal of the charging output to convert the charging current into a voltage signal ISCx and send it to the main control microcontroller module. The voltage divider feedback circuit is used to identify voltage data and switch between boost and buck topologies; The indicator light module is used for independent status display of each channel; The lithium battery output port is electrically connected to an external battery.

[0006] As a further description of the above technical solution: The main control microcontroller module includes the main control microcontroller U2, a voltage regulator circuit, and a bus voltage divider sampling circuit.

[0007] As a further description of the above technical solution: The voltage regulator circuit includes chip U1, capacitor C1, capacitor C2 and VBUS bus input terminal. The VBUS bus is electrically connected to the second pin of chip U1. The third pin of chip U1 outputs a 3.3V DC voltage. Capacitor C2 is connected in parallel with the first and third pins of chip U1 to smooth the 3.3V output ripple. The output 3.3V voltage is connected to the ninth pin of the main control microcontroller U2 to provide working power to the main control microcontroller U2. The bus voltage divider sampling circuit includes resistors R8 and R3 and capacitor C6. The upper end of resistor R8 is electrically connected to the VBUS bus input terminal, the lower end of resistor R8 is connected in series with resistor R3, and capacitor C6 is connected in parallel across resistor R3. The midpoint of the voltage divider between resistors R8 and R3 outputs the SV1 signal, which is connected to the fourth pin of the main control microcontroller U2.

[0008] As a further description of the above technical solution: The Buck step-down circuit includes capacitor C8, resistor R1, MOSFET Q5, transistor Q2, resistor R2, first diode D2, and BUCK1 control signal pin; The VBUS signal is simultaneously connected to capacitor C8 in parallel. The BUCK1 control signal output by the main control microcontroller U2 is connected to resistor R2 and transistor Q2 in sequence. The collector of transistor Q2 is connected to the upper end of resistor R1 and the gate of MOSFET Q5 respectively. The drain of MOSFET Q5 is connected to power inductor L1 through diode D2.

[0009] As a further description of the above technical solution: The boost circuit includes a power inductor L1, a MOSFET Q10, a resistor R4, a BOOST1 signal control pin, and a second diode D2; One end of the power inductor L1 is connected to the drain of the MOSFET Q10 and the anode of the second diode D2. The BOOST1 signal control pin is connected to the resistor R4 and the gate of the MOSFET Q10. The source and collector of the MOSFET Q10 are grounded.

[0010] As a further description of the above technical solution: The voltage divider feedback circuit includes resistor R8, resistor R3, capacitor C6, capacitor C3, and capacitor C10; The positive output terminal BAT+ is connected in parallel with capacitors C3 and C10. A resistor R8 is connected to the upper end of the positive output terminal BAT+. A capacitor C6 is connected in parallel across the two ends of the resistor R3.

[0011] As a further description of the above technical solution: The current sampling and detection circuit includes resistor R10, resistor R9, capacitor C7, and ISC1 sampling signal pin; The positive and negative terminals of the battery are connected between the positive and negative terminals of the output BAT+ and output BAT-. The negative terminal BAT- is connected to resistor R10. The upper end of resistor R10 leads out a sampling point and is electrically connected to the ISC1 sampling signal pin through resistor R9. A capacitor C7 is placed between the ISC1 sampling signal pin and resistor R9.

[0012] As a further description of the above technical solution: The fast charging protocol identification module includes chip U5, and the Type-C input module includes female connector JT1; A small filter capacitor is connected in parallel to ground on pins 1 and 12 of the female connector JT1. Pins 2 and 11 of the female connector JT1 are shorted to output the VBUS bus of the whole machine. One path is pulled up to pin 2 of chip U5, and the other path is connected in series with a resistor to power the subsequent power circuit. Pin 4 of the female connector JT1 is electrically connected to pin 1 of chip U5 through resistor R24. Pin 1 of chip U5 is connected to capacitor C26. Pin 10 of the female connector JT1 is electrically connected to pin 6 of chip U5 through resistor R36. Pins 5 and 8 of the female connector JT1 are shorted and then electrically connected to pin 5 of chip U5 through resistor R16. Pins 6 and 7 of the female connector JT1 are shorted and then electrically connected to pin 4 of chip U5 through resistor R17.

[0013] As a further description of the above technical solution: The lithium battery output port can simultaneously insert three 8.4V dual-series lithium batteries. The lithium battery output port is equipped with a reverse connection protection diode. The chip U5 is model HUSB237, the main control microcontroller U2 is model STM8S003FA, and the chip U1 is model HT7533.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention integrates three independent Buck step-down circuits and Boost step-up circuits, which can charge three 8.4V lithium batteries simultaneously. Multiple circuits can achieve synchronous charging without interference between each other, thus improving charging efficiency. Furthermore, the U5 chip equipped with HUSB237 can quickly identify fast charging types and is compatible with 5V ordinary charging heads and PD or QC9V fast charging power supplies. The main control microcontroller U2 can automatically switch between boost and buck topologies, adapting to most Type-C power supply devices on the market. In addition, the battery preheating activation mechanism can increase the charging current in a step-by-step manner, avoiding damage to the battery cells from direct high-current charging of depleted batteries and extending the battery cycle life. The adaptive current limiting and multi-channel dynamic current sharing functions match the front-end power supply in real time to prevent overload damage to the charging head and ensure the consistency of charging current for the three batteries. In addition, the dual-threshold full charge judgment logic set in this invention can double identify the battery full charge and eliminate the risk of overcharging. Each channel is independently equipped with an indicator light module, which can intuitively distinguish between charging and full charge status. Furthermore, the hardware circuit design of this invention is a standardized design, with unified component parameters for the three power circuits, which simplifies production and assembly, enhances circuit stability, and makes costs more controllable. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of the present invention; Figure 2 This is a schematic diagram of the main control microcontroller U2 circuit of the present invention; Figure 3 This is a circuit diagram of the fast charging protocol identification module of the present invention; Figure 4 This is a schematic diagram of the Buck step-down circuit and the Boost step-up circuit of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1-4 The present invention provides a technical solution: a three-channel intelligent battery charger, including a Type-C input module, a fast charging protocol identification module, a main control microcontroller module, a Buck step-down circuit, a Boost step-up circuit, a current sampling and detection circuit, a voltage divider feedback circuit, an indicator light module, and a lithium battery output port; The Type-C input module is used for power supply to the entire device; The fast charging protocol identification module is used to receive input signals from the Type-C input module and identify the fast charging type; The main control microcontroller module is electrically connected to the fast charging protocol identification module, the main control microcontroller module, three Buck step-down circuits, three Boost step-up circuits, current sampling and detection circuit, voltage divider feedback circuit, and three indicator light modules, and performs battery preheating, constant current and constant voltage charging, input power current limiting, multi-channel dynamic current sharing, full charge determination, and overvoltage and overcurrent protection. The main control microcontroller module outputs six PWM drive signals to drive the Buck step-down circuit and the Boost step-up circuit, and outputs three IO levels to drive the indicator light modules to operate. Both the Buck step-down circuit and the Boost step-up circuit are set to three channels, with the three sets of Buck step-down circuits and Boost step-up circuits corresponding to three independent lithium battery charging channels. The Buck step-down circuit only operates in 9V fast charging mode, stepping down the 9V bus voltage to 8.4V to charge the dual-cell lithium battery. The Boost circuit operates only in the 5V normal charging mode, boosting the 5V bus voltage to 8.4V to charge the lithium battery. The main control microcontroller module mutually excludes the switching of the Boost circuit and the Buck circuit, so they will not be turned on at the same time. The current sampling and detection circuit is set to three channels. Each channel outputs a high-precision sampling resistor in series with the negative terminal of the charging output to convert the charging current into a voltage signal ISCx and send it to the main control microcontroller module. The voltage divider feedback circuit is used to identify voltage data and switch between boost and buck topologies; The indicator light module is used for independent status display of each channel; The lithium battery output port is electrically connected to an external battery. Three 8.4V dual-cell lithium batteries can be inserted into the lithium battery output port at the same time. The lithium battery output port is equipped with a reverse connection protection diode, which can prevent the lithium battery from being damaged due to reverse connection during charging.

[0018] Please see Figures 1-4 The main control microcontroller module includes a main control microcontroller U2, a voltage regulator circuit, and a bus voltage divider sampling circuit. The main control microcontroller U2 is an STM8S003FA. The voltage regulator circuit includes a chip U1, capacitors C1 and C2, and a VBUS bus input terminal. The chip U1 is an HT7533. The VBUS bus is electrically connected to the second pin of the chip U1. The third pin of the chip U1 outputs a 3.3V DC voltage. Capacitor C2 is connected in parallel with the first and third pins of the chip U1 to smooth the output of 3V. The 3V output ripple is connected to the ninth pin of the main control microcontroller U2 to provide operating power for the main control microcontroller U2. The bus voltage divider sampling circuit includes resistors R8 and R3 and capacitor C6. The upper end of resistor R8 is electrically connected to the VBUS bus input terminal, and the lower end of resistor R8 is connected in series with resistor R3. Capacitor C6 is connected in parallel across resistor R3 to filter out high-frequency interference. The midpoint of the voltage divider between resistors R8 and R3 outputs the SV1 signal and is connected to the fourth pin of the main control microcontroller U2.

[0019] The device accepts a wide input voltage of 5V or 9V, while a regulated power supply circuit provides a stable 3.3V output to power the main control microcontroller U2. Regardless of whether the VBUS input is 5V (normal) or 9V (fast charging), the output remains constant at 3.3V. Input and output capacitors filter high-frequency noise from the switching power supply, ensuring a clean power supply to the main control microcontroller U2 and preventing ADC sampling distortion. A bus voltage divider sampling circuit adapts to the VBUS voltage of the main control microcontroller U2, which is 5V or 9V, exceeding its 3.3V ADC sampling range. Resistors R8 and R3 divide the 5V or 9V voltage to a low-voltage signal within 0-3V, which is then safely input to the ADC pin of the main control microcontroller U2. The main control microcontroller U2 reads the SV divider voltage and calculates the actual VBUS voltage. When the detected voltage is approximately 5V, it is determined to be a normal charging head, and the Boost circuit is activated. Detected voltage ≈ 9V: It is determined to be a PD / QC fast charging head, and the Buck step-down circuit is activated. At this time, it is the core judgment basis for the microcontroller to automatically switch between boost or buck topology. When the input undervoltage or overvoltage fault detection continuously monitors the VBUS bus voltage, if the voltage is too low or abnormally high, the main control microcontroller U2 will trigger input adaptive current limiting to reduce the charging output current and protect the front-end power supply equipment.

[0020] Please see Figures 1-4 The Buck step-down circuit includes capacitor C8, resistor R1, MOSFET Q5, transistor Q2, resistor R2, first diode D2, and BUCK1 control signal pin. The VBUS signal is connected in parallel with capacitor C8, which is an input high-frequency filter capacitor to smooth the VBUS bus voltage and suppress switching noise. The BUCK1 control signal output by the main control microcontroller U2 is connected to resistor R2 and transistor Q2 in sequence. The collector of transistor Q2 is connected to the upper end of resistor R1 and the gate of MOSFET Q5, respectively. The drain of MOSFET Q5 is connected to power inductor L1 through diode D2.

[0021] When the BUCK1 control signal outputs a high level, transistor Q2 is turned on and pulls the gate of MOSFET Q5 low. MOSFET Q5 is turned on, and the VBUS signal supplies power to power inductor L1 through MOSFET Q5. When the BUCK1 control signal outputs a low level, transistor Q2 is cut off, and resistor R1 pulls the gate of MOSFET Q5 up to VBUS, turning off MOSFET Q5 and cutting off the input. The main control microcontroller U2 controls the buck output voltage to stabilize at 8.4V by adjusting the PWM duty cycle of the BUCK1 signal. Diode D2 is connected in parallel between the left end of power inductor L1 and GND. When MOSFET Q5 is turned off, power inductor L1 releases induced current, which freewheels through diode D2, protecting MOSFET Q5 from being broken down by reverse high voltage.

[0022] Please see Figures 1-4 The Boost converter circuit includes a power inductor L1, a MOSFET Q10, a resistor R4, a BOOST1 signal control pin, and a second diode D2. One end of the power inductor L1 is connected to the drain of the MOSFET Q10 and the anode of the second diode D2. The BOOST1 signal control pin is connected to the resistor R4 and the gate of the MOSFET Q10. The source and collector of the MOSFET Q10 are grounded.

[0023] When the BOOST1 control signal is high, MOSFET Q10 is turned on, the right end of power inductor L1 is grounded, and the VBUS signal controls MOSFET Q5 to be constantly turned on and controls power inductor L1 to store energy. When the BOOST1 control signal is low, MOSFET Q10 is turned off, and power inductor L1 generates a high voltage induced by the left side being negative and the right side being positive. This voltage is superimposed on the VBUS voltage and rectified by diode D2 to output a high voltage. Diode D2 is unidirectionally turned on, blocking the current from flowing back into the inductor from the output side, and only allowing the boosted energy of power inductor L1 to be output to the next stage.

[0024] Please see Figures 1-4 The voltage divider feedback circuit includes resistors R8 and R3, capacitors C6, C3, and C10; capacitors C3 and C10 are connected in parallel to the positive output BAT+ to form an output LC filter, which smooths the 8.4V DC charging voltage. Resistor R8 is connected to the upper end of the positive output BAT+, and capacitor C6 is connected in parallel across resistor R3 to filter out high-frequency noise from the sampling.

[0025] As a further description of the above technical solution: The current sampling and detection circuit includes resistors R10 and R9, capacitor C7, and an ISC1 sampling signal pin. The positive and negative terminals of the battery are connected between the positive and negative output terminals BAT+ and BAT-. The negative output terminal BAT- is connected to resistor R10. The upper end of resistor R10 leads out a sampling point and is electrically connected to the ISC1 sampling signal pin through resistor R9. A capacitor C7 is placed between the ISC1 sampling signal pin and resistor R9.

[0026] In this circuit, resistor R10 is connected in series in the negative terminal of the charging circuit. All the charging current flows through resistor R10, forming a voltage difference across it, which is proportional to the charging current. When the sampling signal is extracted: the sampling point is led out from the upper end of resistor R10 and output to the ISC1 acquisition signal pin through resistor R9; while capacitor C7 is connected in parallel to the ISC1 acquisition signal pin to filter out high-frequency interference from the switch; the signal flow is sent to the main control microcontroller U2 to read the position of the ISC1 acquisition signal pin and use the voltage to calculate the real-time charging current, thereby realizing constant current control, multi-channel current sharing, and overcurrent limiting protection. The Buck step-down branch and the Boost step-up branch share the same energy storage power inductor L1. The two branches will not conduct simultaneously, and the main control microcontroller U2 controls them according to the mutual exclusion of the VBUS voltage. When VBUS=9V in fast charging mode: BOOST1 control signal continuously outputs low level, MOSFET Q10 is permanently turned off; only BUCK1 control signal outputs PWM, the circuit acts as a Buck converter, and the 9V voltage drops to 8.4V for charging; When VBUS=5V is a standard 5V connector: the BUCK1 control signal continuously outputs a high level, and the MOSFET Q5 is permanently turned on; only the BOOST1 control signal outputs PWM, and the circuit acts as a boost converter to raise the 5V voltage to 8.4V for charging.

[0027] The fast charging protocol identification module includes chip U5, model number HUSB237; the Type-C input module includes female connector JT1. A small filter capacitor is connected in parallel to ground on pins 1 and 12 of the female connector JT1. Pins 2 and 11 of the female connector JT1 are shorted to output the VBUS bus of the whole machine. One path is pulled up to pin 2 of chip U5, and the other path is connected in series with a resistor to power the subsequent power circuit. Pin 4 of the female connector JT1 is electrically connected to pin 1 of chip U5 through resistor R24. Pin 1 of chip U5 is connected to capacitor C26. Pin 10 of the female connector JT1 is electrically connected to pin 6 of chip U5 through resistor R36. Pins 5 and 8 of the female connector JT1 are shorted and then electrically connected to pin 5 of chip U5 through resistor R16. Pins 6 and 7 of the female connector JT1 are shorted and then electrically connected to pin 4 of chip U5 through resistor R17.

[0028] When in use, firstly, when the TYPEC cable is plugged in for power supply, the main control microcontroller U2 and chip U1 start to work. Chip U1 starts to identify and judge fast charging protocols such as PD and QC. If it is identified as fast charging, it will establish communication and change the input voltage from 5V to 9V for fast charging input to power the circuit bus. If no communication signal is identified, it will maintain the original 5V power supply. The main control microcontroller U2 continuously checks the input voltage and the battery status at the output terminal, detecting whether the input is 5V or 9V and whether there is a battery at the output. It then proceeds to the next instruction based on the detection results. Operating mode 1, Boost mode, input 5V boost output 8.4V: The voltage is divided by resistors R12 and R11, filtered by capacitor C12, and then sent to pin 8 of the main microcontroller U2. When pin 8 of the main microcontroller U2 detects 5V, the charger operates in boost mode. Pins 1, 6, and 17 of the main microcontroller U2 send boost PWM drive circuit signals to drive multiple MOSFETs Q10 and power inductor L1 to operate in boost mode. The voltage is then fed back to pins 20, 5, and 16 of the main microcontroller U2 through multiple resistors R8 and R3. After detecting the divided voltage, the main microcontroller U2 controls the output voltage to 8.4V to charge the lithium battery via PWM control. When the charging current generates voltage through multiple resistors R10, the detected voltage is fed back to pins 3, 19, and 16 of the main microcontroller U2. The main microcontroller U2 uses the feedback signal to keep the charging current of all three channels constant at 600mA. Each battery's charging circuit operates in a constant voltage and constant current state after continuous monitoring by the main control microcontroller U2, continuously charging the battery. The microcontroller U2 detects voltage and current to determine the battery's operating status and full charge. Pins 14, 12, and 13 of the microcontroller U2 control the battery's indicator light module to show its operating status. In conjunction with pin 11, when battery 1 is charging, pin 14 of the microcontroller U2 outputs a high level, and pin 11 outputs a low level. When the lithium battery is fully charged, pin 14 goes low, while pin 11 outputs a high level. The other two circuits operate in the same way as the first circuit.

[0029] Operating mode two, buck mode, input 9V, output 8.4V: The voltage is divided by resistors R12 and R11 and filtered by capacitor C12 to generate a voltage to pin 8 of the main microcontroller U2. When pin 8 of the main microcontroller U2 detects a voltage of 9V, the charger operates in buck mode. When 9V is detected, the charger operates in buck mode. The sixth, second, and eighteenth pins of the main microcontroller U2 send buck drive circuit signals to enable the circuit to operate in buck mode, and output voltage of 8.4V to charge the lithium battery. After starting the charging process, the charger will load a small current starting value and enter the battery small current preheating and activation stage, allowing the battery to gradually adapt to high current charging, improving battery life, and continuously increasing the charging current at a rate of 10mA / second until the maximum set charging current is reached. If the battery is replaced in the middle, the preheating and activation function will be restarted. When the input current is insufficient or the connection impedance is too high, in order to prevent the charger from stalling, the charger automatically enters the input current adaptive working mode. It automatically reduces or increases the charging output current according to the effective input power, and at the same time automatically and dynamically balances the charging current of each battery to maintain the consistency of the current as much as possible, so as to match the output power with the maximum input function. Charging power allocation: When the charger is in 5V slow charging mode, the maximum input power is limited to about 5V or 3A. When the charger is in 9V fast charging mode, the maximum input power is limited to about 9V or 2.5A to avoid excessive input current, which may affect the operation of the input power supply equipment and lines. When the microcontroller detects that the battery voltage exceeds the overvoltage value of 8.41V through the voltage divider circuit, or when the charging current drops to about 100mA, it determines that the battery is ready.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A three-channel intelligent battery charger, characterized in that: It includes a Type-C input module, a fast charging protocol identification module, a main control microcontroller module, a Buck step-down circuit, a Boost step-up circuit, a current sampling and detection circuit, a voltage divider feedback circuit, an indicator light module, and a lithium battery output port; The Type-C input module is used for power supply of the entire device; The fast charging protocol identification module is used to receive input signals from the Type-C input module and identify the fast charging category; The main control microcontroller module is electrically connected to the fast charging protocol identification module, the main control microcontroller module, three Buck step-down circuits, three Boost step-up circuits, a current sampling and detection circuit, a voltage divider feedback circuit, and a three-way indicator light module, and performs battery preheating, constant current and constant voltage charging, input power current limiting, multi-channel dynamic current sharing, full charge determination, and overvoltage and overcurrent protection. The main control microcontroller module outputs six PWM drive signals to drive the Buck step-down circuits and Boost step-up circuits, and outputs three IO levels to drive the indicator light module to operate. Both the Buck step-down circuit and the Boost step-up circuit are configured as three-way circuits, with the three sets of Buck step-down circuits and Boost step-up circuits corresponding to three independent lithium battery charging channels. The Buck step-down circuit operates only in 9V fast charging mode, stepping down the 9V bus voltage to 8.4V to charge the dual-cell lithium battery. The Boost circuit operates only in the 5V normal charging mode, boosting the 5V bus voltage to 8.4V to charge the lithium battery. The main control microcontroller module mutually excludes the switching of the Boost circuit and the Buck circuit, preventing them from conducting simultaneously. The current sampling and detection circuit is set to three channels. Each channel outputs a high-precision sampling resistor in series with the negative terminal of the charging output to convert the charging current into a voltage signal ISCx and send it to the main control microcontroller module. The voltage divider feedback circuit is used to identify voltage data and switch between boost and buck topologies; The indicator light module is used for independent status display of each channel; The lithium battery output port is electrically connected to an external battery.

2. A three-channel intelligent battery charger according to claim 1, characterized in that: The main control microcontroller module includes a main control microcontroller U2, a voltage regulator circuit, and a bus voltage divider sampling circuit.

3. A three-channel intelligent battery charger according to claim 2, characterized in that: The voltage regulator circuit includes chip U1, capacitor C1, capacitor C2 and VBUS bus input terminal. The VBUS bus is electrically connected to the second pin of chip U1. The third pin of chip U1 outputs a 3.3V DC voltage. Capacitor C2 is connected in parallel with the first and third pins of chip U1 to smooth the 3.3V output ripple. The output 3.3V voltage is connected to the ninth pin of the main control microcontroller U2 to provide working power to the main control microcontroller U2. The bus voltage divider sampling circuit includes resistors R8 and R3 and capacitor C6. The upper end of resistor R8 is electrically connected to the VBUS bus input terminal, the lower end of resistor R8 is connected in series with resistor R3, and capacitor C6 is connected in parallel across resistor R3. The midpoint of the voltage divider between resistors R8 and R3 outputs the SV1 signal, which is connected to the fourth pin of the main control microcontroller U2.

4. A three-channel intelligent battery charger according to claim 3, characterized in that: The Buck step-down circuit includes capacitor C8, resistor R1, MOSFET Q5, transistor Q2, resistor R2, first diode D2, and BUCK1 control signal pin; The VBUS signal is simultaneously connected to capacitor C8 in parallel. The BUCK1 control signal output by the main control microcontroller U2 is connected to resistor R2 and transistor Q2 in sequence. The collector of transistor Q2 is connected to the upper end of resistor R1 and the gate of MOSFET Q5, respectively. The drain of MOSFET Q5 is connected to power inductor L1 through diode D2.

5. A three-channel intelligent battery charger according to claim 4, characterized in that: The Boost circuit includes a power inductor L1, a MOSFET Q10, a resistor R4, a BOOST1 signal control pin, and a second diode D2. One end of the power inductor L1 is connected to the drain of the MOSFET Q10 and the anode of the second diode D2. The BOOST1 signal control pin is connected to the resistor R4 and the gate of the MOSFET Q10. The source and collector of the MOSFET Q10 are grounded.

6. A three-channel intelligent battery charger according to claim 5, characterized in that: The voltage divider feedback circuit includes resistor R8, resistor R3, capacitor C6, capacitor C3, and capacitor C10; The positive output terminal BAT+ is connected in parallel with capacitors C3 and C10, and a resistor R8 is connected to the upper end of the positive output terminal BAT+. A capacitor C6 is connected in parallel across the two ends of the resistor R3.

7. A three-channel intelligent battery charger according to claim 6, characterized in that: The current sampling and detection circuit includes resistor R10, resistor R9, capacitor C7, and ISC1 sampling signal pin; The positive output terminal BAT+ and the negative output terminal BAT- are connected to the positive and negative terminals of the battery. The negative output terminal BAT- is connected to a resistor R10. The upper end of the resistor R10 leads out a sampling point and is electrically connected to the ISC1 sampling signal pin through a resistor R9. A capacitor C7 is provided between the ISC1 sampling signal pin and the resistor R9.

8. A three-channel intelligent battery charger according to claim 7, characterized in that: The fast charging protocol identification module includes a chip U5, and the Type-C input module includes a female connector JT1; The first and twelfth pins of the female connector JT1 are connected in parallel with a small filter capacitor to ground. The second and eleventh pins of the female connector JT1 are shorted to output the VBUS bus of the whole machine. One path is pulled up to the second pin of the chip U5, and the other path is connected in series with a resistor to power the subsequent power circuit. The fourth pin of the female connector JT1 is electrically connected to the first pin of the chip U5 through a resistor R24. The first pin of the chip U5 is connected to a capacitor C26. The tenth pin of the female connector JT1 is electrically connected to the sixth pin of the chip U5 through a resistor R36. The fifth and eighth pins of the female connector JT1 are shorted and then electrically connected to the fifth pin of the chip U5 through a resistor R16. The sixth and seventh pins of the female connector JT1 are shorted and then electrically connected to the fourth pin of the chip U5 through a resistor R17.

9. A three-channel intelligent battery charger according to claim 8, characterized in that: The lithium battery output port can simultaneously insert three 8.4V dual-series lithium batteries, and the lithium battery output port is equipped with a reverse connection protection diode.

10. A three-channel intelligent battery charger according to claim 9, characterized in that: The chip U5 is model HUSB237, the main control microcontroller U2 is model STM8S003FA, and the chip U1 is model HT7533.

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