A charging method of a fast charging circuit

Abstract

The application provides a charging method of a fast charging circuit, which comprises the following steps: firstly, identifying the fast charging protocol of a device to be charged through a fast charging protocol circuit, and then outputting a feedback voltage required for charging according to the fast charging protocol; then inputting the feedback voltage into a microprocessor and an operational amplifier circuit, and outputting a control signal by the microprocessor through the input voltage and the feedback voltage; then outputting a PWM signal through a PID controller; converting the PWM signal into an analog voltage and inputting the analog voltage into the operational amplifier circuit; calculating an output voltage by the operational amplifier circuit through the feedback voltage and the analog voltage; then controlling a step-down circuit to adjust the output voltage; detecting the difference between an output current and a maximum current during the charging process; and controlling the start and stop of a step-down chip according to the difference. The PID algorithm is used for calculation, the output power is adjusted in real time, the transient performance of the fast charging circuit is improved, and the stability of the charging is ensured.

Description

Technical Field

[0001] This invention relates to the field of fast charging technology, and more specifically to a charging method for a fast charging circuit. Background Technology

[0002] Currently, commonly used high-voltage fast charging technologies include Qualcomm QC (Quick Charge) protocol, MediaTek PE (Pump Express) protocol, Huawei SuperCharge protocol, and USBPD (Power Delivery) protocol. However, existing fast charging protocols are incompatible with each other. Fast charging can only be achieved when the fast charging protocol on the mobile device side is matched with the fast charging protocol on the adapter side. In other words, the mobile device and the adapter must be compatible; otherwise, fast charging cannot be achieved.

[0003] Chinese patent application number 201821494931.1, published on May 21, 2019, discloses a charging connection circuit, chip, and charging connection device with multiple fast charging protocols. The circuit includes a multi-protocol control chip integrating multiple fast charging protocols, and a charging control module, a discharging module, a voltage sampling module, and a current sampling module connected to the multi-protocol control chip. This charging connection circuit, by employing a multi-protocol control chip integrating multiple fast charging protocols, can quickly charge the fast charging device using the appropriate fast charging protocol based on the power supply capacity of the fast charging adapter and the power requirements of the fast charging device, thereby improving the versatility of the circuit and its products. Furthermore, by using a charging control module, the output voltage of the circuit can be effectively controlled, preventing excessively high output voltage from damaging the fast charging device.

[0004] However, this fast charging method does not consider comparing the output voltage with the input voltage during the charging process to adjust the output power in real time, thus preventing damage to the device being charged due to a sudden increase in transient power caused by a low input voltage followed by a high input voltage. Summary of the Invention

[0005] This invention provides a charging method for a fast charging circuit, which compares the feedback voltage of the device with the input voltage of the step-down circuit, adjusts the output power in real time, improves the transient performance of the fast charging circuit, and ensures the stability of charging.

[0006] To achieve the above objectives, the technical solution of the present invention is: a charging method for a fast charging circuit, the fast charging circuit including a microprocessor, a power supply circuit, a voltage regulator circuit, a conversion circuit, a voltage acquisition circuit, a current acquisition circuit, and a fast charging protocol circuit; the conversion circuit includes a step-down circuit, a compensation circuit, and an operational amplifier circuit; the power supply circuit is connected to the voltage regulator circuit, and the voltage regulator circuit supplies power to the voltage acquisition circuit, the current acquisition circuit, the fast charging protocol circuit, the compensation circuit, and the operational amplifier circuit, including the following steps:

[0007] S1, the port of the USB chip in the fast charging protocol circuit is connected to the device to be charged; the device to be charged is then charged normally.

[0008] S2, the fast charging protocol circuit obtains the fast charging protocol of the device to be charged, and obtains the feedback voltage according to the fast charging protocol of the device to be charged.

[0009] S3. The input voltage to the step-down circuit and the feedback voltage obtained by the fast charging protocol circuit are input to the voltage acquisition circuit; the feedback voltage obtained by the fast charging protocol circuit is also input to the operational amplifier.

[0010] S4, the voltage acquisition circuit inputs the input voltage and feedback voltage to the microprocessor.

[0011] S5. The microprocessor calculates the input voltage and feedback voltage; then it outputs a PWM signal based on the calculation results.

[0012] S6, the PWM signal is converted into an analog voltage and then input to the operational amplifier.

[0013] S7. The operational amplifier calculates the analog voltage converted from the feedback voltage and PWM signal; calculates the output voltage V; and then inputs the adjustment signal of the output voltage V into the buck chip of the buck circuit.

[0014] S8, the step-down chip adjusts the output voltage V to quickly charge the device.

[0015] S9. The microprocessor obtains the output current value by collecting data from the device to be charged.

[0016] S10. Determine the value between the output current and the maximum current. If the output current is greater than 20% of the maximum current, proceed to S11; if the output current is less than 20% of the maximum current, proceed to S12.

[0017] S11, the microprocessor outputs a high level to the compensation circuit, the compensation circuit outputs a signal to the buck chip, and the buck chip works normally; then repeat S10.

[0018] S12. The microprocessor outputs a low level to the compensation circuit, which then outputs a signal to the buck chip. The buck chip stops working, and consequently, the buck circuit stops working.

[0019] The above method first identifies the fast charging protocol of the device to be charged through a fast charging protocol circuit, and then outputs the feedback voltage required for charging according to the fast charging protocol. The feedback voltage is then input to a microprocessor and operational amplifier circuit. The microprocessor outputs a PWM signal based on the input voltage and feedback voltage. The PWM signal is converted into an analog voltage and input to the operational amplifier circuit. The operational amplifier circuit calculates the output voltage using the feedback voltage and the analog voltage, and then controls the buck circuit to adjust the output voltage. During charging, the difference between the output current and the maximum current is detected. The buck chip is controlled to start and stop based on this difference. This ensures that when the difference between the input voltage and the output voltage is large, the output voltage is adjusted. The buck chip's start and stop are also adjusted based on the difference between the output current and the maximum current during charging. This prevents the output voltage from being reduced when the output current is too small, thus preventing a sudden drop in current. Conversely, when the output current is too large, the output voltage is reduced to prevent a sudden drop in voltage, thereby further ensuring that the instantaneous output power is neither too high nor too low, and ensuring charging stability.

[0020] Furthermore, S1 also includes: setting a delay timer; starting the delay timer after the USB port is connected to the device; and charging the device normally after the delay timer has finished calculating.

[0021] The above methods, by setting a delay time limit, can prevent excessively large initial voltage pulses from damaging the equipment.

[0022] Furthermore, the step-down circuit includes a step-down chip, inductor L1, polarized capacitors C2, C3, C4, C5, C6, C7, resistors R1, R9, and R10.

[0023] The compensation circuit includes chip U2, resistor R2, capacitor C10 and capacitor C11; the VCC terminal of the power supply circuit is connected to one end of capacitor C3 and the VIN terminal of the step-down chip, and the GND terminal of the power supply circuit is grounded and connected to the other end of capacitor C3 and the GND terminal of the step-down chip.

[0024] The GND terminal of the step-down chip is connected to the V+ terminal of chip U2 through capacitor C4. The V+ terminal of chip U2 is also connected to the voltage regulator circuit. The COMP terminal of the step-down chip is connected to the COM terminal of chip U2. The NO terminal of chip U2 is grounded and connected to one end of resistor R2 and one end of capacitor C11. The other end of resistor R2 is connected to one end of capacitor C10. The other ends of capacitor C11 and capacitor C10 are connected to the NC terminal of chip U2. The GND terminal of chip U2 is grounded. The IN terminal of chip U2 is connected to the CONT terminal of the microprocessor.

[0025] A capacitor C5 and a resistor R1 are connected in series between the COMP terminal of the step-down chip and the COM terminal of chip U2, and capacitor C5 and resistor R1 are grounded.

[0026] S12 is followed by S13-S14.

[0027] S13. Set the charging time limit. The charging time limit starts counting down. When the charging time limit ends, proceed to S14.

[0028] S14. The microprocessor outputs a high level to the compensation circuit. The COM terminal of chip U2 in the compensation circuit is connected to the NO terminal of the compensation chip. The buck circuit works normally and outputs current to quickly charge the device again.

[0029] The above methods ensure that the device has sufficient power.

[0030] Furthermore, the delay time limit is 0.5s.

[0031] Furthermore, the charging time limit is 20 minutes.

[0032] Furthermore, the fast charging protocol circuit includes a fast charging protocol chip, resistors R11, R12, and R13, capacitor C12, and a port for the USB chip.

[0033] The SW terminal of the step-down chip is connected to one end of the polarized capacitor C2 through inductor L1. The other end of the polarized capacitor C2 is grounded and connected to one end of resistor R10. Capacitor C7 is connected in parallel with polarized capacitor C2. One end of resistor R10 is connected to the PGND terminal of the step-down chip, and the other end of resistor R10 is connected to the CS terminal of the step-down chip. The other end of resistor R10 is connected to one end of resistor R11 through resistor R12 and the FB terminal of the fast charging protocol chip. The other end of resistor R11 is connected to the voltage acquisition circuit. The FB terminal of the fast charging protocol chip is also connected to the operational amplifier circuit and the FB1 terminal of the microprocessor. The FB terminal of the step-down chip is also connected to the operational amplifier circuit.

[0034] The voltage acquisition circuit is connected to the VIN terminal of the step-down chip, and is also connected to the SW terminal of the step-down chip through inductor L1. The voltage acquisition circuit is also connected to one end of resistor R13, the other end of resistor R13 is connected to one end of capacitor C12 and the VBUS terminal of the fast charging protocol chip, the other end of capacitor C12 is connected to the GND terminal of the fast charging protocol chip and the other end of resistor R10; the DP and DM terminals of the fast charging protocol chip are connected to the ports of the USB chip.

[0035] The current acquisition circuit includes a current acquisition chip, resistors R18, R19, and R20. The OUTPUT1 terminal of the current acquisition chip is connected to one end of resistor R18, the other end of resistor R18 is connected to one end of resistor R19 and the INPUT1- terminal of the current acquisition chip, and the other end of resistor R19 is grounded. The INPUT1+ terminal of the current acquisition chip is connected to resistor R12 through resistor R20. The VCC terminal of the current acquisition chip is connected to the VOUT terminal of the three-terminal voltage regulator integrated circuit. The GND terminal, OUTPUT2 terminal, INPUT2- terminal, and INPUT2+ terminal of the current acquisition chip are grounded.

[0036] Furthermore, the power supply circuit includes a power supply terminal P1, a polarized capacitor C13, a capacitor C15, a polarized capacitor C16, a capacitor C17, a three-terminal voltage regulator integrated circuit, and a capacitor C14.

[0037] The VCC terminal of power supply terminal P1 is connected to one end of capacitor C15, one end of capacitor C16, one end of capacitor C17, one end of capacitor C3, and the VIN terminal of the step-down chip in sequence through polarized capacitor C13; the GND terminal of power supply terminal P1 is connected to the other end of capacitor C15, the other end of polarized capacitor C16, one end of capacitor C17, the other end of capacitor C3, and the GND terminal of the step-down chip and grounded.

[0038] The VIN terminal of the three-terminal voltage regulator IC is connected to capacitors C15, C16, C17, C3, and C13. The GND terminal of the three-terminal voltage regulator IC is grounded. The VOUT terminal of the three-terminal voltage regulator IC is grounded through capacitor C14 and supplies power to the voltage acquisition circuit, current acquisition circuit, and fast charging protocol circuit.

[0039] Furthermore, the voltage acquisition circuit includes a voltage acquisition chip, resistors R14, R15, R16, and R17.

[0040] The OUTPUT1 and INPUT1- terminals of the voltage acquisition chip are both connected to the VINout terminal of the microprocessor. The INPUT1+ terminal of the voltage acquisition chip is connected to capacitor C3 and the VIN terminal of the step-down chip through resistor R14. The INPUT1+ terminal of the voltage acquisition chip is also connected to the GND terminal of the voltage acquisition chip through resistor R15 and grounded. The VCC terminal of the voltage acquisition chip is connected to the VOUT terminal of the three-terminal voltage regulator integrated circuit. The OUTPUT2 and INPUT2- terminals of the voltage acquisition chip are both connected to the VBUSout terminal of the microprocessor. The INPUT2+ terminal of the voltage acquisition chip is connected to resistors R11 and R13 through resistor R16. The INPUT2+ terminal of the voltage acquisition chip is also grounded through resistor R17.

[0041] Furthermore, the operational amplifier circuit includes an operational amplifier, a diode D1, resistors R3, R4, R5, R6, R7, and R8, and capacitors C8 and C9.

[0042] The +VS terminal of the operational amplifier is connected to the VOUT terminal of the three-terminal voltage regulator IC. The -INB terminal of the operational amplifier is connected in sequence to resistors R4, R7, R8, and the PWM terminal of the microprocessor. One end of resistor R7 is grounded through capacitor C8, and the other end of resistor R7 is grounded through the other end of capacitor C9. One end of resistor R4 is also connected to the OUTB terminal of the operational amplifier through resistor R3. The OUTB terminal of the operational amplifier is also connected to the anode of diode D1, and the cathode of diode D1 is connected to the FB terminal of the buck converter chip. The +INB terminal of the operational amplifier is connected to the FB terminal of the fast charging protocol chip and the FB1 terminal of the microprocessor through resistor R5. The +INB terminal of the operational amplifier is also grounded through resistor R6. The -INA, +INA, and GND terminals of the operational amplifier are grounded.

[0043] Furthermore, in S7, through V=[ R12*(V FB -V PWM The output voltage V is calculated using R14.

[0044] S11 specifically involves the microprocessor outputting a high level to the compensation circuit, connecting the COM terminal of the compensation chip to the NO terminal of the compensation chip, and the buck circuit operating normally to output current; then S10 is repeated.

[0045] S12 specifically means that the microprocessor outputs a low level to the compensation circuit, the COM terminal of the compensation chip is connected to the NC terminal of the compensation chip and grounded, which pulls the level of the COMP terminal of the buck chip down to zero, the buck chip stops working, and thus the buck circuit stops outputting current. Attached Figure Description

[0046] Figure 1 A schematic block diagram illustrating the fast charging circuit of this invention.

[0047] Figure 2 The circuit diagram for implementing the fast charging circuit of the present invention.

[0048] Figure 3 for Figure 2 A magnified view of part a.

[0049] Figure 4 for Figure 2 A magnified view of part b in the image.

[0050] Figure 5 for Figure 2 A magnified view of part c.

[0051] Figure 6 for Figure 2 A magnified view of part d.

[0052] Figure 7 for Figure 2 A magnified view of part e in the image.

[0053] Figure 8 The circuit diagram of the microprocessor in the fast charging circuit of this invention. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0055] like Figure 1-8 As shown; a charging method for a fast charging circuit, the fast charging circuit including...

[0056] The circuit includes a microprocessor 1, a power supply circuit 2, a voltage regulator circuit 3, a conversion circuit, a voltage acquisition circuit 4, a current acquisition circuit 5, and a fast charging protocol circuit 6. In this embodiment, the microprocessor 1 is an STM32F103RCT6.

[0057] like Figure 2-4 As shown; the power supply circuit includes power terminal P1, polarized capacitor C13, capacitor C15, polarized capacitor C16, capacitor C17, three-terminal voltage regulator IC and capacitor C14.

[0058] The conversion circuit includes a step-down circuit 71, a compensation circuit 72, and an operational amplifier circuit 73. The step-down circuit 71 includes a step-down chip U1, an inductor L1, polarized capacitors C2, C3, C4, C5, C6, and C7, and resistors R1, R9, and R10. In this embodiment, the step-down chip U1 is an EUP3270WIR1.

[0059] The VCC terminal of power supply terminal P1 is connected to one end of capacitor C15, one end of polarized capacitor C16, one end of capacitor C17, one end of capacitor C3, and the VIN terminal of step-down chip U1 through electrolytic capacitor C13; the GND terminal of power supply terminal P1 is connected to and grounded to the other end of capacitor C15, the other end of polarized capacitor C16, the other end of capacitor C17, the other end of capacitor C3, and the GND terminal of step-down chip U1.

[0060] The VIN terminal of the three-terminal voltage regulator IC is connected to capacitors C15, C16, C17, C3, and C13. The GND terminal of the three-terminal voltage regulator IC is grounded. The VOUT terminal of the three-terminal voltage regulator IC is grounded through capacitor C14 and supplies power to voltage acquisition circuit 4, current acquisition circuit 5, and fast charging protocol circuit 6.

[0061] like Figure 1 , 5 As shown; the compensation circuit 72 includes chip U2, resistor R2, capacitor C10 and capacitor C11; in this embodiment, the chip U2 is model SGM3157.

[0062] The GND terminal of the step-down chip U1 is connected to the V+ terminal of the chip U2 through capacitor C4. The V+ terminal of the chip U2 is also connected to the voltage regulator circuit 3. The COMP terminal of the step-down chip U1 is connected to the COM terminal of the chip U2. The NO terminal of the chip U2 is grounded and connected to one end of resistor R2 and one end of capacitor C11. The other end of resistor R2 is connected to one end of capacitor C10. The other ends of capacitor C11 and capacitor C10 are connected to the NC terminal of the chip U2. The GND terminal of the chip U2 is grounded. The IN terminal of the chip U2 is connected to the CONT terminal of the microprocessor 1.

[0063] A capacitor C5 and a resistor R1 are connected in series between the COMP terminal of the step-down chip U1 and the COM terminal of the chip U2. The capacitor C5 and the resistor R1 are grounded.

[0064] like Figure 1 , 6 As shown, the fast charging protocol circuit 6 includes a fast charging protocol chip U4, resistors R11, R12, and R13, capacitor C12, and a port for the USB chip. In this embodiment, the fast charging protocol chip U4 is model IP2161.

[0065] The SW terminal of the buck converter chip U1 is connected to one end of the polarized capacitor C2 through inductor L1. The other end of the polarized capacitor C2 is grounded and connected to one end of resistor R10. Capacitor C7 is connected in parallel with polarized capacitor C2. One end of resistor R10 is connected to the PGND terminal of the buck converter chip U1, and the other end of resistor R10 is connected to the CS terminal of the buck converter chip U1. The other end of resistor R10 is connected to one end of resistor R11 and the FB terminal of fast charging protocol chip U4 through resistor R12. The other end of resistor R11 is connected to voltage acquisition circuit 4. Resistor R12 is also connected to current acquisition circuit 5. The FB terminal of fast charging protocol chip U4 is also connected to the operational amplifier circuit and the FB1 terminal of the microprocessor. The FB terminal of buck converter chip U1 is also connected to operational amplifier circuit 73.

[0066] The voltage acquisition circuit is connected to the VIN terminal of the step-down chip U1, and is also connected to the SW terminal of the step-down chip U1 through inductor L1; the voltage acquisition circuit 4 is also connected to one end of resistor R13, the other end of resistor R13 is connected to one end of capacitor C12 and the VBUS terminal of fast charging protocol chip U4, the other end of capacitor C12 is connected to the GND terminal of fast charging protocol chip U4 and the other end of resistor R10; the DP terminal and DM terminal of fast charging protocol chip U4 are connected to the port of USB chip.

[0067] like Figure 1 , 4 As shown; the voltage acquisition circuit 4 includes a voltage acquisition chip U5, resistors R14, R15, R16, and R17. In this embodiment, the voltage acquisition chip U5 is an SGM3157.

[0068] The OUTPUT1 and INPUT1- terminals of voltage acquisition chip U5 are both connected to the VINout terminal of microprocessor 1. The INPUT1+ terminal of voltage acquisition chip U5 is connected to capacitor C3 and the VIN terminal of chip U1 through resistor R14. The INPUT1+ terminal of voltage acquisition chip U5 is also connected to the GND terminal of voltage acquisition chip U5 through resistor R15 and grounded. The VCC terminal of voltage acquisition chip U5 is connected to the VOUT terminal of the three-terminal voltage regulator integrated circuit. The OUTPUT2 and INPUT2- terminals of voltage acquisition chip U5 are both connected to the VBUSout terminal of microprocessor 1. The INPUT2+ terminal of voltage acquisition chip U5 is connected to resistors R11 and R13 through resistor R16. The INPUT2+ terminal of voltage acquisition chip U5 is also grounded through resistor R17.

[0069] like Figure 1 , 7As shown; the current acquisition circuit 5 includes a current acquisition chip U6, resistors R18, R19 and R20; in this embodiment, the current acquisition chip U6 is an SGM3157 gain amplifier.

[0070] The OUTPUT1 terminal of the current acquisition chip U6 is connected to one end of resistor R18. The other end of resistor R18 is connected to one end of resistor R19 and the INPUT1- terminal of the current acquisition chip U6. The other end of resistor R19 is grounded. The INPUT1+ terminal of the current acquisition chip U6 is connected to resistor R12 through resistor R20. The VCC terminal of the current acquisition chip U6 is connected to the VOUT terminal of the three-terminal voltage regulator IC. The GND, OUTPUT2, INPUT2-, and INPUT2+ terminals of the current acquisition chip U6 are grounded. The OUTPUT1 terminal of the current acquisition chip U6 is also connected to the VCSout terminal of the microprocessor.

[0071] like Figure 1 , 5 As shown; the operational amplifier circuit 73 includes operational amplifier U3, diode D1, resistors R3, R4, R5, R6, R7, R8, capacitor C8, and capacitor C9.

[0072] The +VS terminal of operational amplifier U3 is connected to the VOUT terminal of the three-terminal voltage regulator IC. The -INB terminal of operational amplifier U3 is connected in sequence to resistors R4, R7, R8 and the PWM terminal of microprocessor 1. One end of resistor R7 is grounded through capacitor C8, and the other end of resistor R7 is grounded through the other end of capacitor C9. One end of resistor R4 is also connected to the OUTB terminal of operational amplifier U3 through resistor R3. The OUTB terminal of operational amplifier U3 is also connected to the anode of diode D1. The cathode of diode D1 is connected to the FB terminal of buck converter U1. By setting diode D1, signal backflow is prevented.

[0073] The voltage regulator circuit outputs 5V to power chip U2, voltage acquisition chip, current acquisition chip, fast charging protocol chip, and operational amplifier chip. The filtered voltage from the power supply circuit is input to the buck converter chip, and then forms a loop with the fast charging protocol circuit through the buck converter chip's SW and PGND terminals, thus powering the fast charging protocol circuit.

[0074] In the fast charging protocol circuit, after the device to be charged is connected to the port of the USB chip of the fast charging protocol circuit, the DP and DM terminals of the fast charging protocol chip are connected to the device to be charged to identify the fast charging protocol of the device. In this embodiment, the fast charging protocol chip identifies the voltage of the device to be charged and thus identifies the fast charging protocol of the device; the fast charging protocol chip's identification of the fast charging protocol of the device is prior art and will not be described in detail here.

[0075] Then, a feedback voltage is output according to the required charging voltage of the device to be charged. Resistors R11 and R12 are connected to the FB terminal of the fast charging protocol chip. The feedback voltage from the FB terminal of the fast charging protocol chip is input to the INPUT2+ terminal of the voltage acquisition chip, and then input to the microprocessor through the OUTPUT2 and INPUT2- terminals of the voltage acquisition chip. Since the INPUT1+ terminal of the voltage acquisition chip is connected to the VIN terminal of the buck converter chip, the voltage acquisition chip inputs the input voltage to the buck converter circuit to the microprocessor through the OUTPUT1 and INPUT1- terminals of the voltage acquisition chip.

[0076] The microprocessor adjusts the PWM signal based on the feedback voltage and the input voltage. The PWM signal is then fed into the operational amplifier circuit, where it is converted into an analog voltage via resistors R7 and R8, and capacitors C8 and C9, before being input to the operational amplifier. PWM The feedback voltage V at the FB terminal of the fast charging protocol chip FB The calculation is performed, and the calculated output voltage is input to the buck converter chip. Specifically, the operational amplifier uses V=[R12*(V FB -V PWM )] / R14; Calculate the output voltage V of the step-down circuit.

[0077] The voltage input to the power supply circuit is stepped down by a buck converter. After passing through inductor L1 and being filtered by electrolytic capacitors C2 and C7, the voltage is then input to the port of the USB chip in the fast charging protocol circuit. This buck circuit sets the current maximum output voltage of the fast charging circuit.

[0078] The current acquisition circuit and resistor R10 are both connected to resistor R12; the output current flowing through resistor R10 is amplified by resistors R18, R19 and R20 and then input to the current acquisition chip and then input to the VCSout terminal of the microprocessor.

[0079] Meanwhile, in the buck circuit, the maximum current value allowed to pass through the buck circuit is set by resistor R10; the current flowing through resistor R10 is the output current of the buck circuit; the output current is detected by the CS terminal of the buck chip; the COMP terminal of the buck chip is a compensation pin, and the start and stop of the buck chip is controlled by adjusting the level of the COMP terminal of the buck chip.

[0080] The charging method for fast charging circuits includes the following steps:

[0081] S1. The port of the USB chip in the fast charging protocol circuit is connected to the device to be charged; a delay time limit is set; after the USB chip port is connected to the device, the delay time limit starts counting; after the delay time limit is calculated, the device to be charged is charged normally. In this embodiment, the delay time limit is 0.5s. Setting the delay time limit avoids damage to the device to be charged caused by an excessively large initial voltage pulse.

[0082] S2, the fast charging protocol circuit obtains the fast charging protocol of the device to be charged, and obtains the feedback voltage V according to the device's fast charging protocol. FB .

[0083] S3, the input voltage to the buck circuit and the feedback voltage V obtained from the fast charging protocol circuit. FB The voltage is input to the voltage acquisition circuit; the feedback voltage obtained by the fast charging protocol circuit is also input to the operational amplifier.

[0084] S4, the voltage acquisition circuit inputs the input voltage and feedback voltage to the microprocessor.

[0085] S5. The microprocessor calculates the input voltage and feedback voltage; then it outputs a PWM signal based on the calculation results.

[0086] S6, the PWM signal is converted into an analog voltage and then input to the operational amplifier.

[0087] S7, the operational amplifier will feed back voltage V FB The analog voltage V converted from the PWM signal PWM Perform the calculation; using V=[R12*(V FB -V PWM The output voltage V is calculated using R14; then the adjustment signal for the output voltage V is input to the buck chip of the buck circuit.

[0088] S8, the step-down chip adjusts the output voltage V to quickly charge the device.

[0089] S9. The microprocessor obtains the output current value by collecting data from the device to be charged.

[0090] S10. Determine the value between the output current and the maximum current. If the output current is greater than 20% of the maximum current, proceed to S11; if the output current is less than 20% of the maximum current, proceed to S12.

[0091] S11. The microprocessor outputs a high level to the compensation circuit, connecting the COM terminal and the NO terminal of the compensation chip, and the buck circuit operates normally. Then repeat S10.

[0092] S12. The microprocessor outputs a low level to the compensation circuit. The COM terminal of the compensation chip is connected to the NC terminal of the compensation chip and grounded, which pulls the level of the COMP terminal of the buck chip down to zero. The buck chip stops working, and thus the buck circuit stops working.

[0093] S13. Set the charging time limit. The charging time limit starts counting down. When the charging time limit ends, proceed to S14. In this embodiment, the charging time limit is 20 minutes.

[0094] S14, the microprocessor outputs a high level to the compensation circuit, the COM terminal of chip U2 is connected to the NO terminal of the compensation chip, the buck circuit works normally and outputs current to quickly charge the device again; then S10 is repeated.

[0095] The above method first identifies the fast charging protocol of the device to be charged through a fast charging protocol circuit, and then outputs the feedback voltage required for charging according to the fast charging protocol. The feedback voltage is then input to a microprocessor and operational amplifier circuit. The microprocessor outputs a PWM signal based on the input voltage and feedback voltage. The PWM signal is converted into an analog voltage and input to the operational amplifier circuit. The operational amplifier circuit calculates the output voltage using the feedback voltage and the analog voltage, and then controls the buck circuit to adjust the output voltage. During charging, the difference between the output current and the maximum current is detected. The buck chip is controlled to start and stop based on this difference. This ensures that when the difference between the input voltage and the output voltage is large, the output voltage is adjusted. The buck chip's start and stop are also adjusted based on the difference between the output current and the maximum current during charging. This prevents the output voltage from being reduced when the output current is too small, thus preventing a sudden drop in current. Conversely, when the output current is too large, the output voltage is reduced to prevent a sudden drop in voltage, thereby further ensuring that the instantaneous output power is neither too high nor too low, and ensuring charging stability.

Claims

1. A charging method for a fast charging circuit, characterized in that: Includes the following steps: S1. The port of the USB chip in the fast charging protocol circuit is connected to the device to be charged; the device to be charged is then charged normally. S2, the fast charging protocol circuit obtains the fast charging protocol of the device to be charged, and obtains the feedback voltage according to the fast charging protocol of the device to be charged; S3. The input voltage to the step-down circuit and the feedback voltage obtained by the fast charging protocol circuit are input to the voltage acquisition circuit; the feedback voltage obtained by the fast charging protocol circuit is also input to the operational amplifier. S4. The voltage acquisition circuit inputs the input voltage and feedback voltage to the microprocessor; S5. The microprocessor calculates the input voltage and feedback voltage; then it outputs a PWM signal based on the calculation results. S6, the PWM signal is converted into an analog voltage and then input to the operational amplifier; S7. The operational amplifier calculates the analog voltage converted from the feedback voltage and PWM signal; calculates the output voltage V; and then inputs the adjustment signal of the output voltage V into the buck chip of the buck circuit. S8, the step-down chip adjusts the output voltage V to quickly charge the device to be charged; S9. The microprocessor obtains the output current value by collecting data from the device to be charged. S10. Determine the values ​​of the output current and the maximum current. If the output current is greater than 20% of the maximum current, proceed to S11; if the output current is less than 20% of the maximum current, proceed to S12. S11. The microprocessor outputs a high level to the compensation circuit, the compensation circuit outputs a signal to the buck chip, and the buck chip works normally; then S10 is repeated. S12. The microprocessor outputs a low level to the compensation circuit, which then outputs a signal to the buck chip. The buck chip stops working, and consequently, the buck circuit stops working.

2. The charging method for a fast charging circuit according to claim 1, characterized in that: S1 also includes: setting a delay timer; the delay timer starts counting down after the USB chip's port is connected to the device to be charged; and normal charging of the device to be charged is performed after the delay timer expires.

3. The charging method for a fast charging circuit according to claim 1, characterized in that: S12 is followed by S13-S14; S13. Set the charging time limit. The charging time limit starts counting down. When the charging time limit ends, proceed to S14. S14. The microprocessor outputs a high level to the compensation circuit. The COM terminal of the compensation chip in the compensation circuit is connected to the NO terminal of the compensation chip. The buck circuit works normally and outputs current to quickly charge the device to be charged again.

4. The charging method for a fast charging circuit according to claim 2, characterized in that: The delay time limit is 0.5s.

5. The charging method for a fast charging circuit according to claim 3, characterized in that: The charging time limit is 20 minutes.

6. The charging method for a fast charging circuit according to claim 1, characterized in that: S11 specifically involves: the microprocessor outputting a high level to the compensation circuit, connecting the COM terminal of the compensation chip in the compensation circuit to the NO terminal of the compensation chip, and the buck circuit operating normally to output current; then S10 is repeated. S12 specifically means that the microprocessor outputs a low level to the compensation circuit, the COM terminal of the compensation chip is connected to the NC terminal of the compensation chip and grounded, which pulls the level of the COMP terminal of the buck chip down to zero, the buck chip stops working, and thus the buck circuit stops outputting current.

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