CN219018511U

CN219018511U - Under-voltage shutdown circuit of battery

Info

Publication number: CN219018511U
Application number: CN202223337186.9U
Authority: CN
Inventors: 周启航; 李强; 周学成; 宋元淳; 黄亮
Original assignee: Weisheng Energy Technology Co ltd
Current assignee: Weisheng Energy Technology Co ltd
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2023-05-12
Anticipated expiration: 2032-12-14

Abstract

The utility model discloses a battery under-voltage turn-off circuit, which comprises a power switch circuit electrically connected with one end of a battery, wherein the power switch circuit is electrically connected with the under-voltage turn-off circuit, and the under-voltage turn-off circuit is electrically connected with the other end of the battery; when the main power supply is connected, the main power supply supplies power to the system and simultaneously charges the battery. When the main power supply is disconnected, the power supply is converted into a battery to supply power for the system. The battery voltage is below the threshold and the battery is shut down. According to the utility model, the under-voltage protection of the storage battery is controlled through a pure hardware circuit, so that the power of the storage battery is not additionally consumed; meanwhile, the problem of frequent switching of the battery at the undervoltage critical point is solved, the pin resource of the chip is not occupied, and the cost is saved.

Description

Under-voltage shutdown circuit of battery

Technical Field

The utility model relates to the field of electricity, in particular to a battery under-voltage shutdown circuit.

Background

The storage battery is used as a standby power supply of the equipment, and can ensure the normal operation of the system in a period of time after the main power supply of the equipment is lost, so that the basic functions of the equipment are maintained. The accumulator itself has the problem of overdischarge, which may cause damage to electrode active material, lose reaction capacity and shorten the life of accumulator. Therefore, preventing the battery from overdischarging is a problem that must be solved using battery power.

The prior common solutions are two, one is to compare the battery voltage with the pre-shutdown voltage by using a comparator, and judge whether the battery is under-voltage or not according to the output of the comparator; one is to accurately collect the value of the battery voltage through an operational amplifier, and monitor the voltage in real time to perform protection turn-off.

But the above schemes all need software and hardware coordination to realize. The voltage value processing and the logic judgment all need a control chip to process, which undoubtedly wastes precious pin resources of the system. On the other hand, when the storage battery supplies power, the detection or comparison circuit uses the voltage of the storage battery, which occupies a part of energy, and when the voltage is insufficient, the circuit can be affected to a certain extent, so that the circuit cannot be turned off in time.

Disclosure of Invention

In order to solve the technical problems, the utility model provides a battery under-voltage shutdown circuit and a manufacturing method thereof.

The aim of the utility model is achieved by the following technical scheme:

the under-voltage turn-off circuit of the battery comprises a power switch circuit electrically connected with one end of the battery, wherein the power switch circuit is electrically connected with the under-voltage turn-off circuit, and the under-voltage turn-off circuit is electrically connected with the other end of the battery; the power switch circuit comprises a cathode of a rectifying diode D1, a cathode of a rectifying diode D3, a cathode of a voltage stabilizing diode D2, one end of a divider resistor R1 and a drain electrode of a PMOS tube V1 which are electrically connected with one end of a battery; the positive electrode of the first rectifying diode D1 is electrically connected with the positive electrode of the third rectifying diode D3, the positive electrode of the second voltage stabilizing diode D2 and the other end of the first voltage dividing resistor R1 are electrically connected with the grid electrode of the first PMOS tube V1, one end of the fourth voltage dividing resistor R4 and the drain electrode of the first NMOS tube Q1; the source electrode of the PMOS tube V1 is electrically connected with the power supply structure VOUT, and the other end of the divider resistor R4 is electrically connected with the undervoltage shutdown circuit; the grid electrode of the NMOS tube I Q1 is electrically connected with the cathode of the voltage stabilizing diode IV D4, one end of the voltage dividing resistor II R2 and one end of the voltage dividing resistor III R3; the positive electrode of the fourth D4 diode, the other end of the third R3 resistor and the source electrode of the first Q1 NMOS tube are grounded.

Further improved, the single tube maximum flux of the rectifier diode one D1 and the rectifier diode three D3 is 3A.

Further improved, the first PMOS tube V1 is a PMOS tube with the model NCE60P82, and the first NMOS tube Q1 is an NMOS tube with the model MMFTN 3400.

The undervoltage turn-off circuit comprises a photoelectric coupler U1 electrically connected with the other end of a resistor R4, and the resistor R4 is electrically connected with a first pin of the photoelectric coupler U1; the second pin of the photoelectric coupler U1 is electrically connected with the first pin of the voltage stabilizer U2, the third pin of the voltage stabilizer U2 is electrically connected with one end of the voltage dividing resistor seven R7 and is grounded, and the second pin of the voltage stabilizer U2 is electrically connected with the third pin of the photoelectric coupler U1, the other end of the voltage dividing resistor seven R7 and one end of the voltage dividing resistor six R6; the other end of the voltage dividing resistor six R6 is electrically connected with a third pin of the photoelectric coupler U1 and one end of the voltage dividing resistor R5, and the other end of the voltage dividing resistor R5 is electrically connected with the other end of the battery.

Further improved, the photo-coupler U1 is a photo-coupler of the LTV 816D.

Further improved, the voltage stabilizer U2 is a voltage stabilizer of TL 431.

The utility model has the beneficial effects that:

1. the under-voltage protection of the storage battery is controlled through a pure hardware circuit, so that the power of the storage battery is not additionally consumed; meanwhile, the problem of frequent switching of the battery at the under-voltage critical point is solved.

2. The chip pin resource is not occupied, and the cost is saved.

Drawings

The utility model is further illustrated by the accompanying drawings, the content of which does not constitute any limitation of the utility model.

Fig. 1 is a schematic circuit structure of the present utility model.

Detailed Description

The utility model will be further described in detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the utility model more apparent.

Example 1

The under-voltage shutdown circuit of the battery shown in fig. 1 mainly comprises two parts: and the power switch circuit and the under-voltage turn-off circuit. When the main power supply is connected, the main power supply supplies power to the system and simultaneously charges the battery. When the main power supply is disconnected, the power supply is converted into a battery to supply power for the system. The battery voltage is below the threshold and the battery is shut down.

A power switching circuit: consists of D1, D2, D3, D4, R1, R4, R2, R3, Q1 and V1 in FIG. 1. D1 and D3 are rectifier diodes, the maximum flux of a single tube is 3A, and the two tubes are connected in parallel to ensure that 5A current can be passed; r1, R4, R2 and R3 are used as voltage dividing resistors; v1 is a PMOS tube with the model NCE60P82, and Q1 is an NMOS tube with the model MMFTN 3400; d2 and D4 are zener diodes for preventing Vgs voltages of V1 and Q1 from exceeding the maximum value that they can withstand;

an undervoltage shutdown circuit: consists of U1, U2, R5, R6 and R7 in figure 1. U1 is a photoelectric coupler of model LTV 816D; u2 is a voltage stabilizer of model TL 431; r5, R6 and R7 are each used as a voltage dividing resistor.

The power supply principle: when the main power is on, the front end generates 27.2V. The voltage is passed through D1, D3 to charge the battery. Meanwhile, the voltage is divided by R2 and R3, so that Vgs of Q1 is larger than Vth, Q1 is conducted, a pin 1 of V1 is grounded, vgs of V1 is smaller than Vth, V1 is conducted, and the voltage supplies power to a system through an interface VOUT.

When the main power is turned off, Q1 is turned off. The voltage of the battery is divided by R5, R6 and R7, so that the voltage of the U2 pin 2 is more than 2.5V, and the

U2 pins

1 and 3 are conducted. The voltage of the V1 pin 1 is obtained by subtracting U1 from the voltage of the battery, and then dividing the voltage by R1 and R4 after the voltage drop of U2, so that Vgs < Vth of V1 can be conducted, and the battery supplies power to the system through the interface VOUT.

The logic of the undervoltage shutdown (after the main power supply is disconnected) is as follows:

when the full battery is connected, the voltage of the battery 27V to the U2 pin 2 after being divided by the resistors R5, R6 and R7 is 2.95V and is larger than the U2 reference voltage of 2.5V, the U2 is conducted, and the battery supplies power to the system. Meanwhile, the optocoupler U1 acts, and pins 3 and 4 of the optocoupler U are communicated. R6 is short-circuited, the voltage of the battery is 3.1V after the voltage is divided by R5 and R7, U2 is still conducted, and the battery is kept powered.

When the battery is in low voltage, the voltage from the battery voltage 22.8V to the U2 pin 2 after being divided by the resistors R5, R6 and R7 is 2.5V, and the U2 is just not conducted. I.e., the battery is below 22.8V access, the battery is disabled from powering the system.

3 after the battery voltage is normally switched on for a period of time: normally connected, the optocoupler U1 acts, the R6 is short-circuited, and the battery voltage is controlled by the partial pressure of the R5 and the R7. In the continuous operation of the battery, the voltage is reduced, when the voltage is reduced to 21.7V, the voltage to the U2 pin 2 after the voltage is divided by R5 and R7 is 2.5V, and the U2 is just not conducted. I.e. 21.7V is the under-voltage off-point. U2 is not conducted, so that the optocoupler U1 does not act, and the battery voltage is controlled by dividing the voltages of R5, R6 and R7. The battery voltage needs to be greater than 22.8V again. Therefore, the problem of frequent turn-on and turn-off caused by voltage fluctuation near the undervoltage turn-off breakpoint is solved.

Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the scope of the present utility model, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solution of the present utility model without departing from the spirit and scope of the technical solution of the present utility model.

Claims

1. The under-voltage turn-off circuit of the battery is characterized by comprising a power switch circuit electrically connected with one end of the battery, wherein the power switch circuit is electrically connected with the under-voltage turn-off circuit, and the under-voltage turn-off circuit is electrically connected with the other end of the battery; the power switch circuit comprises a cathode of a rectifying diode I (D1) electrically connected with one end of the battery, a cathode of a rectifying diode III (D3), a cathode of a voltage stabilizing diode II (D2), one end of a divider resistor I (R1) and a drain electrode of a PMOS tube I (V1); the positive electrode of the first rectifying diode (D1) is electrically connected with the positive electrode of the third rectifying diode (D3), the positive electrode of the second voltage stabilizing diode (D2) and the other end of the first voltage dividing resistor (R1) are electrically connected with the grid electrode of the first PMOS tube (V1), one end of the fourth voltage dividing resistor (R4) and the drain electrode of the first NMOS tube (Q1); the source electrode of the PMOS tube I (V1) is electrically connected with the power supply structure (VOUT), and the other end of the divider resistor IV (R4) is electrically connected with the under-voltage turn-off circuit; the grid electrode of the NMOS tube I (Q1) is electrically connected with the cathode of the voltage stabilizing diode IV (D4), one end of the voltage dividing resistor II (R2) and one end of the voltage dividing resistor III (R3); the positive electrode of the fourth voltage stabilizing diode (D4), the other end of the third voltage dividing resistor (R3) and the source electrode of the first NMOS tube (Q1) are grounded.

2. The under-voltage shutdown circuit of claim 1 wherein the single-tube maximum current capacity of the rectifier diode one (D1) and the rectifier diode three (D3) is 3A.

3. The under-voltage shutdown circuit of claim 1 wherein the first PMOS transistor (V1) is a PMOS transistor of model NCE60P82 and the first NMOS transistor (Q1) is an NMOS transistor of model MMFTN 3400.

4. The battery under-voltage shutdown circuit of claim 1, including a photo coupler (U1) electrically connected to the other end of a resistor four (R4), the resistor four (R4) being electrically connected to a first pin of the photo coupler (U1); the second pin of the photoelectric coupler (U1) is electrically connected with the first pin of the voltage stabilizer (U2), the third pin of the voltage stabilizer (U2) is electrically connected with one end of the voltage dividing resistor seven (R7) and grounded, and the second pin of the voltage stabilizer (U2) is electrically connected with the third pin of the photoelectric coupler (U1), the other end of the voltage dividing resistor seven (R7) and one end of the voltage dividing resistor six (R6); the other end of the voltage dividing resistor (R6) is electrically connected with a third pin of the photoelectric coupler (U1) and one end of the voltage dividing resistor (R5), and the other end of the voltage dividing resistor (R5) is electrically connected with the other end of the battery.

5. The under-voltage battery shutdown circuit of claim 4 wherein the optocoupler (U1) is an optocoupler of LTV 816D.

6. The battery under-voltage shutdown circuit of claim 4 wherein the voltage regulator (U2) is a voltage regulator of TL 431.