CN102005801A - A charging circuit of solar charge controller with common ground structure - Google Patents

Abstract

The invention relates to the technical field of solar power supply circuits, in particular to a charging circuit of a solar charging controller with a common ground structure, which comprises a solar battery, a storage battery, a central processing unit, a PWM (pulse-width modulation) driving circuit, a current sampling circuit and a voltage sampling circuit, wherein the PWM driving circuit, the current sampling circuit and the voltage sampling circuit are connected with the central processing unit, the anti-backflow circuit is connected with the central processing unit and the PWM driving circuit, and the negative electrode of the solar battery and the negative electrode of the storage battery are connected with a common ground GND. The solar cell is sampled by using a method of direct voltage division by using the resistor, the sampling is convenient, the backflow prevention circuit adopts the MOSFET circuit connected into a synchronous rectification mode, and when the PWM signal is switched on, the grid drive of the backflow prevention circuit adopts positive voltage drive, so that the voltage drop loss of a charging loop is greatly reduced, the difficulty of heat dissipation management is reduced, the overall efficiency of the system is effectively improved, the structure is simple, the realization is convenient, and the cost is low.

Description

A charging circuit of solar charge controller with common ground structure

technical field

The invention relates to the technical field of power circuits, in particular to a charging circuit of a solar charging controller with a common ground structure. the

Background technique

At present, there are many types of solar charge controllers on the market, including charging circuits with a common anode structure and a common ground structure. In actual operation, there are some shortcomings:

The charging circuit of some simple solar charge controllers, after the battery is fully charged, short-circuits the positive and negative poles of the solar panel to protect the battery, which will cause the temperature of the solar panel array to be too high and easily damage the solar panel , reducing the service life of solar panels.

The charging circuits of some common positive solar charge controllers have difficulty in sampling the voltage of the solar battery because the negative pole of the solar battery and the negative pole of the storage battery do not share the same ground.

In the design of the anti-backflow circuit of some solar charge controllers, diodes are connected in series to prevent the battery current from flowing back into the solar battery at night. However, during charging, the forward conduction voltage drop of the diode is large, and the conduction loss is large, resulting in low conversion efficiency of the charge controller.

The object of the present invention is to provide a charging circuit for a solar charging controller with a common ground structure, which has high conversion efficiency, convenient solar battery voltage sampling, simple structure, convenient implementation and low cost.

The purpose of the present invention is achieved through the following technical measures: a charging circuit of a solar charge controller with a common ground structure, including a solar cell, a storage battery, a central processing unit, a PWM drive circuit, a current sampling circuit, a voltage sampling circuit, a PWM drive circuit, The current sampling circuit and the voltage sampling circuit are connected to the central processing unit, and an anti-backflow circuit is also included. The anti-backflow circuit is connected to the PWM driving circuit, and the negative pole of the solar cell and the negative pole of the storage battery are connected to the common ground GND.

Among them, it also includes a power MOSFET circuit and an advection circuit. The voltage sampling circuit includes a solar cell voltage sampling circuit and a battery voltage sampling circuit. The power MOSFET circuit is connected with a current sampling circuit, an anti-backflow circuit, and a PWM drive circuit. The first port of the solar cell voltage sampling circuit is connected to the positive pole of the solar cell, the second port of the solar cell voltage sampling circuit is connected to the negative pole of the solar cell, the control port of the solar cell voltage sampling circuit is connected to the central processing unit, and the first port of the battery voltage sampling circuit One port is connected to the positive pole of the solar battery, the second port of the battery voltage sampling circuit is connected to the negative pole of the solar battery, and the control port of the battery voltage sampling circuit is connected to the central processing unit.

Among them, the anti-backflow circuit includes a power MOSFET Q3, a resistor R10, one end of the resistor R10 is connected to the drive signal terminal DRVH of the power MOSFET Q3, and the other end of R10 is connected to the gate of the power MOSFET Q3;

The source of Q3 is connected to the power MOSFET circuit, and the drain of Q3 is connected to the positive pole of the battery.

Wherein, the PWM driving circuit includes a driver U1, capacitors C8 and C9, and a resistor R13, and the pin 3 of U1 is connected to the signal output pin of the central controller;

Pin 1 of U1 is the first output end of the PWM drive circuit;

The pin 5 of U1 is the second output terminal of the PWM driving circuit;

The pin 8 of U1 is the third output end of the PWM driving circuit;

One end of C9 is connected to pin 2 of U1, and the other end of C9 is connected to pin 8 of U1;

One end of C8 is connected to direct current with pin 6 of U1 and pin 7 of U1, and the other end of C8 is grounded;

One end of R13 is connected to pin 3 of U1, and the other end of R13 is connected to pin 4 of U1.

Among them, the power MOSFET circuit includes power MOSFET Q1, Q2, diode D1, resistor R4, and capacitor C3. Diode D1, resistor R4, and capacitor C3 form the absorption circuit of the power MOSFET Q1 on the upper bridge arm, and diode D2, resistor R5, and capacitor C4 form the lower circuit. Snubber circuit of bridge arm power MOSFET Q2;

The positive pole of D1 is connected to one end of R4 and the drain of Q1; the negative pole of D1 is connected to the other end of R4 and one end of C3;

The other end of C3 is connected to the source of Q1, the source of Q3, the drain of Q2, the positive electrode of D2, one end of R5, and the third output end of the PWM drive circuit;

The gate of Q1 is connected to the first output end of the PWM driving circuit;

The negative pole of D2 is connected to the other end of R5 and one end of C4;

The other end of C4 is grounded to the source of Q2;

The gate of Q2 is connected to the second output end of the PWM driving circuit.

Among them, it also includes inductor L1, resistors R1, R2, R3, R6, R7, R8, R9, R11, R12, capacitors C1, C2, C5, C6, C7, diodes ZD1, ZD2, transient voltage suppression diode TVS1, insurance pipe F1;

One end of TVS1 is connected to the positive pole of the solar cell, and the other end of TVS1 is connected to the negative pole of the solar cell;

One end of R1 is connected to the positive pole of the solar cell and one end of L1, and the other end of R1 is connected to one end of R2, one end of C1, and the third signal input pin of the central processing unit;

The other end of R2 is grounded to the negative pole of the solar cell, the other end of C1, the negative pole of C2, and the source of Q2;

The other end of L1 is connected with one end of R3 and the first signal input pin of the CPU;

The other end of R3 is connected to the positive pole of C2, the positive pole of D1, the drain of Q1, and the second signal input pin of the central processing unit;

One end of R7 is connected to the gate of Q1, one end of R6, and the negative pole of ZD1;

The other end of R7 is connected to the anode of ZD1, the source of Q1, the source of Q3, and the third output terminal of the PWM drive circuit;

The other end of R6 is connected to the first output end of the PWM drive circuit;

One end of R9 is connected to the gate of Q2, one end of R8, and the negative pole of ZD2;

The other end of R9 is grounded to the positive pole of ZD2, the source pole of Q2, the negative pole of C5, the negative pole of C6, one end of R12, one end of C7, and the negative pole of the battery;

The other end of R8 is connected to the second output end of the PWM drive circuit;

The positive pole of C5 is connected to the positive pole of C6, one end of R11, the drain of Q3, and one end of F1;

The other end of R11 is connected with the other end of R12, and the other end of C7 is connected with the third signal input end of the central processing unit;

The other end of F1 is connected to the positive pole of the battery.

Among them, R1, R2, R3, R11, R12 are precision resistors.

Among them, U1 is a high-speed synchronous driver U1, the specific model is: TPS38225.

It also includes a lightning protection circuit, one end of the lightning protection circuit is connected to the positive pole of the solar battery, and the other end of the lightning protection circuit is connected to the negative pole of the solar battery.

Among them, the central processing unit is a PSoC central processing unit, and the specific model is: CY8CLED03D02.

The beneficial effect of the present invention is that: a charging circuit of a solar charging controller with a shared ground structure, including a solar battery, a storage battery, a central processing unit, a PWM driving circuit, a current sampling circuit, a voltage sampling circuit, a PWM driving circuit, a current sampling circuit, The voltage sampling circuit is connected with the central processing unit, and an anti-backflow circuit is connected with the PWM drive circuit, and the negative pole of the solar cell and the negative pole of the storage battery are connected to the common ground GND. The present invention adopts a public ground structure and uses the method of directly dividing the voltage of the resistance to sample the solar cell, the voltage sampling of the solar cell is convenient, the anti-backflow circuit adopts a MOSFET circuit connected into a synchronous rectification mode, and when the PWM signal is turned on, the gate drive adopts a positive voltage Drive, effectively reducing the forward conduction voltage drop of the parasitic body diode inside the MOSFET. Compared with the anti-backflow circuit composed of diodes, it greatly reduces the voltage drop loss of the charging circuit, reduces the difficulty of heat dissipation management, and effectively improves The overall efficiency of the system, the structure is simple, the implementation is convenient, and the cost is low.

Description of drawings

Fig. 1 is a system structure block diagram of the present invention;

Fig. 2 is a charging circuit diagram of the present invention;

Fig. 3 is a PWM driving circuit diagram of the charging circuit.

Reference signs:

100 - CPU

101 - storage battery

102——Solar battery voltage sampling circuit

103 - solar cells

104——Battery voltage sampling circuit

105—— PWM drive circuit

106——Anti-backflow circuit

107——Lightning protection circuit

108—Advection circuit

109——Current sampling circuit

110—power MOSFET circuit.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described further, as shown in Figure 1～Figure 3.

Example 1

This embodiment provides a charging circuit of a solar charging controller with a common ground structure, including a solar battery 103, a storage battery 101, a central processing unit 100, a PWM driving circuit 105, a current sampling circuit 109, a voltage sampling circuit, a PWM driving circuit 105, The current sampling circuit 109 and the voltage sampling circuit are connected to the central processing unit 100, and also include an anti-backflow circuit 106, which is connected to the PWM drive circuit 105, and the negative pole of the solar cell 103 and the negative pole of the storage battery 101 are connected to the common ground GND. The present invention adopts a public ground structure, utilizes the method of resistance direct voltage division to sample the solar battery 103, the voltage sampling of the solar battery 103 is convenient, and the anti-backflow circuit 106 adopts a MOSFET circuit connected into a synchronous rectification mode, and when the PWM signal is turned on, its gate drive Driven by a positive voltage, it effectively reduces the forward conduction voltage drop of the parasitic body diode inside the MOSFET. Compared with the anti-backflow circuit formed by the diode in the prior art, it greatly reduces the voltage drop loss of the charging circuit and reduces the heat dissipation management. Difficulties, effectively improving the overall efficiency of the system, simple structure, easy implementation, and low cost.

This embodiment also includes a power MOSFET circuit 110, a smoothing circuit 108, a voltage sampling circuit including a solar cell voltage sampling circuit 102 and a battery voltage sampling circuit 104, a power MOSFET circuit 110, a current sampling circuit 109, an anti-backflow circuit 106, and a PWM drive circuit 105 connection, the smoothing circuit 108 is connected to the positive pole of the solar battery 103, the first port of the solar battery voltage sampling circuit 102 is connected to the positive pole of the solar battery 103, the second port of the solar battery voltage sampling circuit 102 is connected to the negative pole of the solar battery 103, and the solar battery The control port of the voltage sampling circuit 102 is connected with the central processing unit 100, the first port of the battery voltage sampling circuit 104 is connected with the positive pole of the solar battery 103, the second port of the battery voltage sampling circuit is connected with the negative pole of the solar battery 103, and the battery voltage sampling The control port of the circuit 104 is connected with the CPU 100 .

The PWM driving circuit 105 of this embodiment includes a driver U1, capacitors C8, C9, and a resistor R13, and the pin 3 of U1 is connected to the signal output pin of the central controller;

The pin 1 of U1 is the first output end of the PWM driving circuit 105;

The pin 5 of U1 is the second output terminal of the PWM driving circuit 105;

The pin 8 of U1 is the third output end of the PWM driving circuit 105;

One end of C9 is connected to pin 2 of U1, and the other end of C9 is connected to pin 8 of U1;

One end of C8 is connected to direct current with pin 6 of U1 and pin 7 of U1, and the other end of C8 is grounded;

One end of R13 is connected to pin 3 of U1, and the other end of R13 is connected to pin 4 of U1.

The anti-backflow circuit 106 of this embodiment includes a power MOSFET Q3 and a resistor R10, one end of the resistor R10 is connected to the drive signal terminal DRVH of the power MOSFETQ3, and the other end of R10 is connected to the gate of the power MOSFET Q3;

The source of Q3 is connected to the power MOSFET circuit 110 , and the drain of Q3 is connected to the positive electrode of the battery 101 .

The circuit of the power MOSFET circuit 110 of this embodiment adopts a MOSFET half-bridge structure, and the power MOSFET Q1 and Q2 form the main circuit of the power MOSFET circuit 110, and the diode D1, the resistor R4, and the capacitor C3 form the absorption circuit of the upper bridge arm power MOSFET Q1, and the diode D2, resistor R5, and capacitor C4 constitute the absorbing circuit of the lower bridge arm power MOSFET Q2;

The positive pole of D1 is connected to the drain of Q1 at one end of R4; the negative pole of D1 is connected to the other end of R4 and one end of C3;

The other end of C3 is connected to the source of Q1, the source of Q3, the drain of Q2, the anode of D2, one end of R5, and the third output end of the PWM driving circuit 105;

The gate of Q1 is connected to the first output end of the PWM drive circuit 105;

The negative pole of D2 is connected to the other end of R5 and one end of C4;

The other end of C4 is grounded to the source of Q2;

The gate of Q2 is connected to the second output end of the PWM driving circuit 105 .

This embodiment also includes inductor L1, resistors R3, R1, R2, R3, R6, R7, R8, R9, R11, R12, capacitors C1, C2, C5, C6, C7, diodes ZD1, ZD2, transient voltage suppression diodes TVS1, fuse F1;

One end of TVS1 is connected to the positive electrode of the solar cell 103, and the other end of TVS1 is connected to the negative electrode of the solar cell 103;

One end of R1 is connected to the positive pole of the solar cell 103 and one end of L1, and the other end of R1 is connected to one end of R2, one end of C1, and the third signal input pin of the central processing unit 100;

The other end of R2 is grounded to the negative pole of the solar cell 103, the other end of C1, the negative pole of C2, and the source of Q2;

The other end of L1 is connected with one end of R3 and the first signal input pin of the CPU 100;

The other end of R3 is connected to the positive pole of C2, the positive pole of D1, the drain of Q1, and the second signal input pin of the central processing unit 100;

One end of R7 is connected to the gate of Q1, one end of R6, and the negative pole of ZD1;

The other end of R7 is connected to the positive pole of ZD1, the source pole of Q1, the source pole of Q3, and the third output terminal of the PWM driving circuit 105;

The other end of R6 is connected to the first output end of the PWM driving circuit 105;

One end of R9 is connected to the gate of Q2, one end of R8, and the negative pole of ZD2;

The other end of R9 is grounded to the positive pole of ZD2, the source pole of Q2, the negative pole of C5, the negative pole of C6, one end of R12, one end of C7, and the negative pole of battery 101;

The other end of R8 is connected to the second output end of the PWM drive circuit 105;

The positive pole of C5 is connected to the positive pole of C6, one end of R11, the drain of Q3, and one end of F1;

The other end of R11 is connected with the other end of R12, the other end of C7 is connected with the third signal input end of central processing unit 100;

The other end of F1 is connected to the positive pole of the storage battery 101 .

R1, R2, R3, R11 and R12 in this embodiment are precision resistors.

The specific models of the power MOSFETs Q1, Q2 and Q3 in this embodiment are IPB025N10N3.

U1 in this embodiment is a high-speed synchronous driver U1, and the specific model is: TPS38225.

The central processing unit 100 of this embodiment is a PSoC central processing unit, and the specific model is: CY8CLED03D02.

The principle of this embodiment is:

As shown in FIG. 2, the transient voltage suppression diode TVS1 is connected between the positive and negative poles of the input terminal of the solar cell 103;

The sampling of the voltage signal of the solar cell 103 adopts a precise resistance voltage division sampling method. The solar cell 103 voltage divider sampling circuit is composed of precision resistors R1, R2 and capacitor C1. The voltage divider signal PV_sense is sent to the PSoC CPU for A/D conversion to obtain the solar cell 103 voltage signal.

The voltage signal of the storage battery 101 is sampled using a precision resistor voltage divider sampling method. The battery 101 voltage divider sampling circuit is composed of precision resistors R11, R12 and capacitor C7. The voltage divider signal Batt_sense is sent to the PSoC CPU for A/D conversion to obtain the battery 101 voltage signal.

The sampling of the output current of the solar cell 103 adopts the method of series precision resistors, the output current of the solar cell 103 forms voltage difference signals PVCurV+ and PVCurV- at both ends of the precision sampling resistor R3, and sends them to the internal differential operational amplifier of PSoC for differential amplification, and then the PSoC The A/D converting unit of the solar cell 103 performs analog/digital conversion to obtain the output current signal of the solar cell 103.

When measuring the output current of the solar cell 103, a series precision resistor is used, but the output current of the solar cell 103 forms a high common-mode voltage differential signal at both ends of the series precision resistor, and it is difficult to withstand such a high common-mode voltage by using a discrete differential operational amplifier. Differential input voltage, therefore, measuring the output current of the solar cell 103 becomes a difficult problem. The present invention uses the high common-mode voltage differential operational amplifier on the PSoC chip to effectively solve the technical problem of differential amplification of the high common-mode voltage existing in the output current sampling of the solar cell 103, and at the same time, reduce the number of components and components of the peripheral hardware circuit and PCB The board size improves the integration and security of the system.

The PWM driving circuit 105 adopts the high-speed synchronous driver U1 of N-channel complementary driving power MOSFET. After the PWM pulse signal sent by the PSoC central processor passes through the synchronous driver U1, complementary high-end and low-end driving signals are generated, which are respectively added to the MOSFET half-bridge of the charging circuit. The gates of the upper bridge arm and the lower bridge arm MOSFET, the high-side and low-side drive signals have adaptive dead-time control. the

The inductance L1 constitutes the smoothing circuit 108, which functions to smooth the output current of the solar cell 103;

The driving signal DRVH sent by pin 1 of U1 is the driving signal of the power MOSFET Q1 of the upper bridge arm, and the driving signal DRVL sent by the pin 5 of U1 is the driving signal of the power MOSFET Q2 of the lower bridge arm;

As shown in Figure 3, U1 is a high-speed synchronous driver U1 for N-channel complementary drive power MOSFETs. The power supply terminal pin 6 of U1 and U1 pin 7 are connected to the DC power supply VDD2, and the pin 4 of U1 is connected to the common ground GND. The DC power supply VDD2 is connected to the common ground GND through the decoupling capacitor C8. The PWM control signal PWM1 sent by the PSoC central processing unit is sent to the pin 3 of U1, and at the same time, the pin 3 of U1 is connected to the common ground GND through the pull-down resistor R13. Pin 2 of U1 is connected to pin 8 of U1 through capacitor C9, and pin 8 of U1 is connected to the source of power MOSFET Q1. The pin 1 of U1 generates the driving signal DRVH of the upper-arm MOSFET of the power MOSFET half-bridge, and the pin 5 of U1 generates the driving signal DRVL of the lower-arm MOSFET of the power MOSFET half-bridge.

Example 2

In this embodiment, on the basis of Embodiment 1, a lightning protection circuit 107 is added, one end of which is connected to the positive pole of the solar battery 103 , and the other end of the lightning protection circuit 107 is connected to the negative pole of the solar battery 103 .

Since the solar cells 103 are exposed to the outside world, the lightning protection circuit 107 is provided to further protect the solar cells 103 and prolong the service life of the solar cells 103 .

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand , the technical solution of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. The charging circuit of the solar charge controller of a kind of common ground structure, comprises solar battery, accumulator, central processing unit, PWM driving circuit, current sampling circuit, voltage sampling circuit, PWM driving circuit, current sampling circuit, voltage sampling circuit and The central processing unit is connected, and it is characterized in that it also includes an anti-backflow circuit, the anti-backflow circuit is connected with the PWM drive circuit, and the negative pole of the solar cell and the negative pole of the storage battery are connected to the common ground GND. 2. The charging circuit of a solar charge controller with a common ground structure according to claim 1, characterized in that: it also includes a power MOSFET circuit, a leveling circuit, and the voltage sampling circuit includes a solar cell voltage sampling circuit and a storage battery voltage sampling circuit , the power MOSFET circuit is connected to the current sampling circuit, the anti-backflow circuit, and the PWM drive circuit, the advection circuit is connected to the positive pole of the solar battery, the first port of the solar battery voltage sampling circuit is connected to the positive pole of the solar battery, and the second port of the solar battery voltage sampling circuit is connected to the solar battery Connect the negative pole of the battery, the control port of the solar battery voltage sampling circuit is connected to the central processing unit, the first port of the battery voltage sampling circuit is connected to the positive pole of the solar battery, the second port of the battery voltage sampling circuit is connected to the negative pole of the solar battery, the battery voltage The control port of the sampling circuit is connected with the central processing unit. 3. The charging circuit of a solar charging controller with a common ground structure according to claim 2, wherein the anti-backflow circuit includes a power MOSFET Q3, a resistor R10, one end of the resistor R10 and the drive signal terminal DRVH of the power MOSFET Q3 Connect, the other end of R10 is connected to the gate of power MOSFET Q3; The source of Q3 is connected to the power MOSFET circuit, and the drain of Q3 is connected to the positive pole of the battery. 4. The charging circuit of a solar charging controller with common ground structure according to claim 3, characterized in that: the PWM driving circuit includes a driver U1, capacitors C8, C9, a resistor R13, the pin 3 of U1 and the central control The signal output pin connection of the device; Pin 1 of U1 is the first output end of the PWM driving circuit; The pin 5 of U1 is the second output end of the PWM driving circuit; The pin 8 of U1 is the third output end of the PWM driving circuit; One end of C9 is connected to pin 2 of U1, and the other end of C9 is connected to pin 8 of U1; One end of C8 is connected to direct current with pin 6 of U1 and pin 7 of U1, and the other end of C8 is grounded; One end of R13 is connected to pin 3 of U1, and the other end of R13 is connected to pin 4 of U1. 5. The charging circuit of a solar charge controller with a common ground structure according to claim 4, wherein the power MOSFET circuit includes power MOSFETs Q1, Q2, diode D1, resistor R4, capacitor C3, diode D1, resistor R4 and capacitor C3 constitute the absorbing circuit of the power MOSFET Q1 of the upper bridge arm, and diode D2, resistor R5 and capacitor C4 constitute the absorbing circuit of the power MOSFET Q2 of the lower bridge arm; The positive pole of D1 is connected to one end of R4 and the drain of Q1; the negative pole of D1 is connected to the other end of R4 and one end of C3; The other end of C3 is connected to the source of Q1, the source of Q3, the drain of Q2, the positive electrode of D2, one end of R5, and the third output end of the PWM drive circuit; The gate of Q1 is connected to the first output end of the PWM driving circuit; The negative pole of D2 is connected to the other end of R5 and one end of C4; The other end of C4 is grounded to the source of Q2; The gate of Q2 is connected to the second output end of the PWM driving circuit. 6. The charging circuit of a solar charging controller with a common ground structure according to claim 5, characterized in that: it also includes an inductor L1, resistors R1, R2, R3, R6, R7, R8, R9, R11, R12 , capacitors C1, C2, C5, C6, C7, diodes ZD1, ZD2, transient voltage suppression diode TVS1, fuse F1; One end of TVS1 is connected to the positive pole of the solar cell, and the other end of TVS1 is connected to the negative pole of the solar cell; One end of R1 is connected to the positive pole of the solar cell and one end of L1, and the other end of R1 is connected to one end of R2, one end of C1, and the third signal input pin of the central processing unit; The other end of R2 is grounded to the negative pole of the solar cell, the other end of C1, the negative pole of C2, and the source of Q2; The other end of L1 is connected with one end of R3 and the first signal input pin of the CPU; The other end of R3 is connected to the positive pole of C2, the positive pole of D1, the drain of Q1, and the second signal input pin of the central processing unit; One end of R7 is connected to the gate of Q1, one end of R6, and the negative pole of ZD1; The other end of R7 is connected to the anode of ZD1, the source of Q1, the source of Q3, and the third output terminal of the PWM drive circuit; The other end of R6 is connected to the first output end of the PWM drive circuit; One end of R9 is connected to the gate of Q2, one end of R8, and the negative pole of ZD2; The other end of R9 is grounded to the positive pole of ZD2, the source pole of Q2, the negative pole of C5, the negative pole of C6, one end of R12, one end of C7, and the negative pole of the battery; The other end of R8 is connected to the second output end of the PWM drive circuit; The positive pole of C5 is connected to the positive pole of C6, one end of R11, the drain of Q3, and one end of F1; The other end of R11 is connected with the other end of R12, and the other end of C7 is connected with the third signal input end of the central processing unit; The other end of F1 is connected to the positive pole of the battery. 7. The charging circuit of a solar charge controller with common ground structure according to claim 6, characterized in that: R1, R2, R3, R11, R12 are precision resistors. 8. The charging circuit of a common-ground solar charge controller according to claim 7, characterized in that: U1 is a high-speed synchronous driver U1, and the specific model is: TPS38225. 9. The charging circuit of a solar charging controller with common ground structure according to claim 1, characterized in that: it also includes a lightning protection circuit, one end of the lightning protection circuit is connected to the positive pole of the solar battery, and the other end of the lightning protection circuit is One end is connected to the negative pole of the solar cell. 10. The charging circuit of a solar charging controller with a common ground structure according to any one of claims 1-9, wherein the central processing unit is a PSoC central processing unit, and the specific model is: CY8CLED03D02.

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