CN218183041U - A battery pack charging protection circuit based on negative electrode control - Google Patents

Abstract

The utility model relates to the technical field of photovoltaic charging protection, and provides a battery pack charging protection circuit based on negative electrode control, which uses a voltage dividing resistor to detect in real time the charging voltage of a charging device on a charging interface, and feeds back to an MCU (main control chip) for processing. The output control signal controls the second switching tube to turn on, thereby turning on the light-emitting device of the optocoupler, so that the photosensitive device is turned on, short-circuiting the first switching tube to turn off the charging circuit of the charging device from the negative pole of the charging interface; Difficult to drive, NMOS tube is used as the main circuit high-current switch, and it also has the characteristics of small internal resistance and voltage drop, low cost, and effectively guarantees the safety of users.

Description

A battery pack charging protection circuit based on negative electrode control

technical field

The utility model relates to the technical field of photovoltaic charging protection, in particular to a battery pack charging protection circuit based on negative electrode control.

Background technique

Solar energy is an inexhaustible, non-polluting green energy bestowed by nature, but it has the characteristics of randomness and intermittent nature.

The solar power supply system consists of solar cell components, solar controllers, and batteries (groups). Inverters can also be configured according to actual needs. Solar energy is a clean, renewable new energy source that plays a wide range of roles in people's lives and work. One of them is to convert solar energy into electrical energy. Solar power generation is divided into photothermal power generation and photovoltaic power generation. Generally speaking, solar power generation refers to solar photovoltaic power generation, which has the characteristics of no moving parts, no noise, no pollution, and high reliability. It has excellent application prospects in communication power supply systems in remote areas.

In the existing energy storage photovoltaic charging circuit, the safety switch is usually set on the positive pole of the charging interface, but the MOS driving circuit of this switch control scheme is relatively complicated, and the current of the positive pole of the charging interface is required not to be too large, otherwise the MOS will be burned. tube, and use the MOS tube to turn off the positive electrode of the charging interface, the control cost is relatively high.

Contents of the invention

The utility model provides a battery pack charging protection circuit based on negative electrode control, which solves the technical problem that the switch control circuit in the existing photovoltaic charging circuit is relatively complicated and the cost is high.

In order to solve the above technical problems, the utility model provides a battery pack charging protection circuit based on negative electrode control, which includes a photovoltaic panel and a charging interface, and is characterized in that it also includes a switch circuit, a voltage detection circuit, a control circuit and a main control module; The positive terminal of the photovoltaic panel is connected to the positive terminal of the charging interface; the voltage detection circuit is connected to the positive terminal of the photovoltaic panel and connected in parallel with the charging interface; the switch circuit is connected in series between the negative terminal of the photovoltaic panel and the negative terminal of the charging interface , the signal terminal is connected to the positive terminal; the power supply terminal of the main control module is connected to the positive terminal, the input terminal is connected to the voltage detection circuit, and the control terminal is connected to the control circuit; the control circuit is connected to the positive terminal of the photovoltaic panel The terminal and the negative terminal are connected, and are also connected to the signal terminal of the switch circuit;

When the charging voltage reaches the preset threshold, the voltage detection circuit will feed back the detected charging voltage of the charging device to the main control module, and the main control module will turn on the control circuit to short-circuit the switch circuit and turn off Open charging output.

In a further embodiment, the switch circuit includes a first resistor, a second resistor, a third resistor, a first diode and a first switch tube, and when the first switch tube is an N-channel MOS tube:

The gate of the first switching tube is connected to the positive terminal through the second resistor and the first resistor, the drain is connected to the negative terminal of the charging interface, and the source is connected to the negative terminal; one terminal of the third resistor is connected to the first terminal The other end of the gate of a switching tube is connected to the negative end; the first diode is connected in parallel with the third resistor.

In a further embodiment, the control circuit includes a fourth resistor, a fifth resistor, a sixth resistor, an optocoupler and a second switch tube, and when the second switch tube is an NPN transistor:

The base of the second switching tube is connected to the control terminal of the main control module through the fifth resistor, connected to the negative electrode of the charging interface through the sixth resistor, the emitter is connected to the negative electrode of the charging interface, and the collector is connected to the negative electrode of the charging interface. Connect with pin 2 of the optocoupler; pin 1 of the optocoupler is connected to the positive terminal, pin 3 is connected to the negative terminal, and pin 4 is connected between the first resistor and the second resistor.

In a further embodiment, the voltage detection circuit includes a seventh resistor, an eighth resistor, a ninth resistor, and a first capacitor, one end of the seventh resistor is connected between the positive terminal and the positive terminal of the charging interface, and the other end The ninth resistor is connected to the negative pole of the charging interface, and the eighth resistor is connected to the input end of the main control module; one end of the first capacitor is connected to the input end of the main control module, and the other end is connected to the input end of the main control module. Negative connection of the charging interface.

In a further embodiment, the main control module includes a voltage regulator, a main control chip, a second capacitor, and a third capacitor; the ground terminal of the voltage regulator is grounded, the output terminal is connected to the main control chip, and the input terminal is connected to the main control chip. The positive end is connected; one end of the second capacitor is connected to the positive end, and the other end is grounded; one end of the third capacitor is connected to the output end of the voltage regulator, and the other end is grounded; the input end of the main control chip It is connected with the control terminal, and the control terminal is connected with the fifth resistor.

In a further embodiment, the regulator is a low dropout linear regulator.

In a further embodiment, the main control chip is an MCU.

In a further embodiment, the optocoupler is a four-pin optocoupler.

The utility model uses a voltage dividing resistor to detect the charging voltage of the charging device on the charging interface in real time, feeds back to the MCU (main control chip) for processing, and outputs a control signal to control the conduction of the second switch tube, thereby turning on the light-emitting device of the optical coupler , so that the photosensitive device is turned on, and the first switch tube is short-circuited to turn off the charging circuit of the charging device from the negative pole of the charging interface; it not only reduces the difficulty of switch driving, but also uses NMOS tubes as the main circuit high-current switch, and also has small internal resistance and low voltage. Reduced features, low cost, and effectively guarantee the safety of users.

Description of drawings

Fig. 1 is a system frame diagram of a battery pack charging protection circuit based on negative electrode control provided by an embodiment of the present invention;

Fig. 2 is the hardware circuit diagram of Fig. 1 that the utility model embodiment provides;

Among them: switch circuit 1, voltage detection circuit 2, control circuit 3, main control module 4;

The first resistor R1 to the ninth resistor R9, the first capacitor C1 to the third capacitor C3, the first switch tube Q1, the second switch tube Q2, the optocoupler U1, the regulator U2, and the main control chip U3.

detailed description

The embodiment of the utility model is explained in detail below in conjunction with the accompanying drawings. The giving of the embodiments is only for the purpose of illustration, and can not be interpreted as a limitation of the utility model. The accompanying drawings are only for reference and description, and do not constitute a patent for the utility model. The limitation of the protection scope is because many changes can be made to the utility model without departing from the spirit and scope of the utility model.

A battery pack charging protection circuit based on negative electrode control provided by the embodiment of the present invention, as shown in Figure 1, in this embodiment, includes a photovoltaic panel and a charging interface, and also includes a switch circuit 1, a voltage detection circuit 2, a control circuit Circuit 3 and main control module 4; the positive terminal of the photovoltaic panel is connected to the positive terminal of the charging interface; the voltage detection circuit 2 is connected to the positive terminal PV+ of the photovoltaic panel, and is also connected in parallel with the charging interface; the switch circuit 1 is connected in series to the negative terminal PV of the photovoltaic panel - Between the negative pole BAT- of the charging interface, its signal terminal is connected to the positive terminal PV+; the power supply terminal of the main control module 4 is connected to the positive terminal PV+, the input terminal is connected to the voltage detection circuit 2, and the control terminal is connected to the control circuit 3; The control circuit 3 is connected to the positive terminal PV+ and the negative terminal PV- of the photovoltaic panel, and is also connected to the signal terminal of the switch circuit 1;

When the charging voltage reaches the preset threshold, the voltage detection circuit 2 feeds back the detected charging voltage of the charging device to the main control module 4, and the main control module 4 turns on the control circuit 3 to short-circuit the switch circuit 1 and disconnect the charging output.

In this embodiment, the preset threshold is the divided voltage on the ninth resistor R9 after the lithium battery is fully charged, or the protection point voltage on AD_bat.

In this embodiment, the switch circuit 1 includes a first resistor R1, a second resistor R2, a third resistor R3, a first diode, and a first switch tube Q1. When the first switch tube Q1 is an N-channel MOS tube :

The gate of the first switching tube Q1 is connected to the positive terminal PV+ through the second resistor R2 and the first resistor R1, the drain is connected to the negative terminal BAT- of the charging interface, and the source is connected to the negative terminal PV-; one terminal of the third resistor R3 is connected to the negative terminal PV- The other end of the gate of the first switching transistor Q1 is connected to the negative terminal PV-; the first diode is connected in parallel with the third resistor R3.

In this embodiment, the control circuit 3 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, an optocoupler U1 and a second switch tube Q2. When the second switch tube Q2 is an NPN transistor:

The base of the second switching tube Q2 is connected to the control terminal of the main control module 4 through the fifth resistor R5, connected to the negative pole BAT- of the charging interface through the sixth resistor R6, the emitter is connected to the negative pole BAT- of the charging interface, and the collector Connect with pin 2 of the optocoupler U1; pin 1 of the optocoupler U1 is connected with the positive terminal PV+, pin 3 is connected with the negative terminal PV-, and pin 4 is connected between the first resistor R1 and the second resistor R2.

In this embodiment, the voltage detection circuit 2 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a first capacitor C1, and one end of the seventh resistor R7 is connected between the positive terminal BAT+ and the positive terminal PV+ of the charging interface. , the other end is connected to the negative pole BAT- of the charging interface through the ninth resistor R9, and connected to the input end of the main control module 4 through the eighth resistor R8; one end of the first capacitor C1 is connected to the input end of the main control module 4, and the other end is connected to the input end of the main control module 4. The negative BAT- connection of the charging interface.

In this embodiment, the main control module 4 includes a voltage regulator U2, a main control chip U3, a second capacitor C2, and a third capacitor C3; the ground terminal of the voltage regulator U2 is grounded, the output terminal is connected to the main control chip U3, and the input One end of the second capacitor C2 is connected to the positive end PV+, and the other end is grounded; one end of the third capacitor C3 is connected to the output end of the voltage regulator U2, and the other end is grounded; the input end of the main control chip U3 It is connected with the control terminal, and the control terminal is connected with the fifth resistor R5.

In this embodiment, the regulator U2 includes but not limited to a low dropout linear regulator U2.

In this embodiment, the main control chip U3 includes but is not limited to an MCU.

In this embodiment, the optocoupler U1 is a four-pin optocoupler.

The charging protection principle of this embodiment is as follows:

Connect the charging device to the charging interface (BAT+, BAT-), the positive terminal PV+ outputs the voltage to the gate of the first switching tube Q1, the drain and source of the first switching tube Q1 are turned on, and charging starts.

The photovoltaic power supply thus inputs the positive terminal PV+ into the voltage regulator U2, and the voltage regulator U2 inputs the power supply to the main control chip U3 after voltage regulation.

At this time, the main control chip U3 collects the divided voltage of the charging voltage through the input terminal (AD sampling terminal) and the eighth resistor R8. When the divided voltage on the nine resistors R9 or the protection point voltage on AD_bat, the main control chip U3 outputs a high level from the control terminal, controls the second switch tube Q2 to be turned on, the photocoupler is turned on, and the first switch tube Q1 is pulled down grid potential, the first switching tube Q1 is turned off, and the charging output is disconnected.

The utility model uses a voltage dividing resistor to detect the charging voltage of the charging device on the charging interface in real time, feeds back to the MCU (main control chip U3) for processing, and outputs a control signal to control the conduction of the second switch tube Q2, thereby conducting the optical coupler U1 The light-emitting device makes the photosensitive device turn on, and short-circuits the first switch tube Q1 to turn off the charging circuit of the charging device from the negative pole BAT- of the charging interface; it not only reduces the difficulty of switch driving, and uses NMOS tube as the main circuit high-current switch, but also It has the characteristics of small internal resistance, low pressure drop, low cost, and effectively guarantees the safety of users.

The above-mentioned embodiment is a preferred implementation mode of the present utility model, but the implementation mode of the present utility model is not limited by the above-mentioned embodiment, and any other changes, modifications and substitutions made without departing from the spirit and principle of the present utility model , combination, and simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present utility model.

Claims (8)

1. The utility model provides a battery package protection circuit that charges based on negative pole control, includes photovoltaic board and the interface that charges, its characterized in that: the device also comprises a switch circuit, a voltage detection circuit, a control circuit and a main control module; the positive terminal of the photovoltaic panel is connected with the positive electrode of the charging interface; the voltage detection circuit is connected with the positive terminal of the photovoltaic panel and is also connected with the charging interface in parallel; the switching circuit is connected in series between the negative electrode end of the photovoltaic panel and the negative electrode of the charging interface, and the signal end of the switching circuit is connected with the positive electrode end; the power end of the main control module is connected with the positive end, the input end of the main control module is connected with the voltage detection circuit, and the control end of the main control module is connected with the control circuit; the control circuit is connected with the positive electrode end and the negative electrode end of the photovoltaic panel and is also connected with the signal end of the switch circuit;

when the charging voltage reaches a preset threshold value, the voltage detection circuit feeds the charging voltage of the charging equipment back to the main control module, and the main control module conducts the control circuit to short circuit the switch circuit and disconnect the charging output.

2. The negative control-based battery pack charging protection circuit of claim 1, wherein the switch circuit comprises a first resistor, a second resistor, a third resistor, a first diode and a first switch transistor, and when the first switch transistor is an N-channel MOS transistor:

the grid electrode of the first switching tube is connected with the positive electrode end through the second resistor and the first resistor, the drain electrode of the first switching tube is connected with the negative electrode of the charging interface, and the source electrode of the first switching tube is connected with the negative electrode end; one end of the third resistor is connected with the grid electrode of the first switching tube, and the other end of the third resistor is connected with the negative electrode end; the first diode is connected in parallel with the third resistor.

3. The negative control-based battery pack charging protection circuit of claim 2, wherein the control circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, an optocoupler, and a second switch transistor, and when the second switch transistor is an NPN-type transistor:

the base electrode of the second switching tube is connected with the control end of the main control module through the fifth resistor and is connected with the negative electrode of the charging interface through the sixth resistor, the emitting electrode of the second switching tube is connected with the negative electrode of the charging interface, and the collecting electrode of the second switching tube is connected with the pin 2 of the optical coupler; and a pin 1 of the optical coupler is connected with the positive end, a pin 3 of the optical coupler is connected with the negative end, and a pin 4 of the optical coupler is connected between the first resistor and the second resistor.

4. The negative control-based battery pack charging protection circuit of claim 1, wherein: the voltage detection circuit comprises a seventh resistor, an eighth resistor, a ninth resistor and a first capacitor, one end of the seventh resistor is connected between the positive electrode and the negative electrode of the charging interface, and the other end of the seventh resistor is connected with the negative electrode of the charging interface through the ninth resistor and is connected with the input end of the main control module through the eighth resistor; first electric capacity one end with host system's input is connected, and the other end is connected with the negative pole of the interface that charges.

5. The negative control-based battery pack charging protection circuit of claim 3, wherein: the main control module comprises a voltage stabilizer, a main control chip, a second capacitor and a third capacitor; the grounding end of the voltage stabilizer is grounded, the output end of the voltage stabilizer is connected with the main control chip, and the input end of the voltage stabilizer is connected with the positive end; one end of the second capacitor is connected with the positive electrode end, and the other end of the second capacitor is grounded; one end of the third capacitor is connected with the output end of the voltage stabilizer, and the other end of the third capacitor is grounded; the input end of the main control chip is connected with the control end, and the control end is connected with the fifth resistor.

6. The negative control-based battery pack charging protection circuit of claim 5, wherein: the voltage stabilizer is a low dropout linear voltage stabilizer.

7. The negative control-based battery pack charging protection circuit of claim 5, wherein: the main control chip is an MCU.

8. The negative control-based battery pack charging protection circuit of claim 3, wherein: the optical coupler is a four-pin optical coupler.

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