Battery access protection circuit
By designing a battery access protection circuit, which combines functions such as slow-start overvoltage protection, reverse connection protection, surge absorption, and output filtering, the problem of overvoltage damage to electronic devices during battery replacement is solved, achieving safe protection and stable power supply for battery access.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2026-04-03
AI Technical Summary
When replacing batteries in existing electronic devices, there is a common problem of incompatible batteries being connected, leading to excessively high voltage and damage to the device.
A battery connection protection circuit was designed, including a slow-start overvoltage protection circuit, a reverse connection protection circuit, a surge absorption circuit, a connection indicator circuit, an output filter circuit, and a fuse. Through the combination of resistors, capacitors, Zener diodes, transistors, and MOSFETs, the circuit achieves protection and stable output of the battery voltage.
It effectively prevents overvoltage damage when incompatible batteries are connected, provides reverse connection protection, absorbs surge current, improves EMI performance, and displays the battery connection status through indicator lights to ensure output voltage stability and safety.
Smart Images
Figure CN224083185U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic equipment, and in particular to a battery access protection circuit. Background Technology
[0002] Many existing electronic devices (such as emergency lights) use replaceable batteries. However, when users replace batteries, it is easy to accidentally connect an incompatible battery to the electronic device. If the voltage of the connected battery is too high, it can easily damage the electronic device.
[0003] In view of the above problems, it is necessary to study a battery access protection circuit that can effectively protect electronic devices when a battery is connected. Utility Model Content
[0004] The purpose of this invention is to provide a battery access protection circuit that can effectively protect electronic devices when a battery is connected to them.
[0005] To achieve the above objectives, the solution of this utility model is:
[0006] A battery access protection circuit includes a battery access port CAN1, a soft-start overvoltage protection circuit, and a power output port VOUT. The soft-start overvoltage protection circuit includes resistors R3, R4, R5, R6, and R9, capacitor C3, Zener diode D3, transistor Q3, and MOSFET Q1. The first terminal of resistor R3, the emitter of transistor Q3, and the source of MOSFET Q1 are connected to the input terminal of the soft-start overvoltage protection circuit. The second terminal of resistor R3 is connected to the negative terminal of Zener diode D3 and the first terminal of resistor R5. The positive terminal of Zener diode D3 is connected to input ground GND1, and the second terminal of resistor R5 is connected to resistor R... The first terminal of R9, the first terminal of capacitor C3, and the base of transistor Q3 are connected. The collector of transistor Q3 is connected to the second terminal of capacitor C3, the first terminal of resistor R4, and the first terminal of resistor R6. The second terminal of resistor R4 is connected to output ground GND2. The second terminal of resistor R6 is connected to the gate of MOSFET Q1. The drain of MOSFET Q1 and the second terminal of resistor R9 are connected to the output terminal of the soft-start overvoltage protection circuit. The positive terminal of battery input port CAN1 is connected to the input terminal of the soft-start overvoltage protection circuit, and the negative terminal of battery input port CAN1 is connected to input ground GND1. The power supply output port VOUT is connected to the output terminal of the soft-start overvoltage protection circuit.
[0007] The slow-start overvoltage protection circuit also includes a capacitor C4 and a Zener diode D4. The first terminal of the capacitor C4 and the negative terminal of the Zener diode D4 are connected to the source of the MOSFET Q1, and the second terminal of the capacitor C4 and the positive terminal of the Zener diode D4 are connected to the gate of the MOSFET Q1.
[0008] The battery access protection circuit also includes a reverse connection protection circuit, which connects the input ground GND1 and the output ground GND2. The reverse connection protection circuit includes a resistor R2 and a MOSFET Q2. The first end of the resistor R2 is connected to the positive terminal of the battery access port CAN1, the second end of the resistor R2 is connected to the gate of the MOSFET Q2, the drain of the MOSFET Q2 is connected to the input ground GND1, and the source of the MOSFET Q2 is connected to the output ground GND2.
[0009] The reverse connection protection circuit also includes a Zener diode D2 and a capacitor C2. The first end of the capacitor C2 and the negative terminal of the Zener diode D2 are connected to the gate of the MOSFET Q2, and the second end of the capacitor C2 and the positive terminal of the Zener diode D2 are connected to the source of the MOSFET Q2.
[0010] The battery access protection circuit also includes a surge absorption circuit; the surge absorption circuit includes a bidirectional Zener diode D1, a resistor R1 and a capacitor C1, the first positive terminal of the bidirectional Zener diode D1 and the first end of the resistor R1 are connected to the positive terminal of the battery access port CAN1, the second end of the resistor R1 is connected to the first end of the capacitor C1, and the first end of the capacitor C1 and the second positive terminal of the bidirectional Zener diode D1 are connected to the input ground GND1.
[0011] The battery access protection circuit also includes an access indicator circuit; the access indicator circuit includes a resistor R8 and an indicator LED1. The first end of the resistor R8 is connected to the positive terminal of the battery access port CAN1, the second end of the resistor R8 is connected to the positive terminal of the indicator LED1, and the negative terminal of the indicator LED1 is connected to the input ground GND1.
[0012] The battery access protection circuit also includes an output filtering circuit, which includes a resistor R7 and a capacitor C5. The first end of the resistor R7 is connected to the power supply output port VOUT, the second end of the resistor R7 is connected to the first end of the capacitor C5, and the second end of the capacitor C5 is connected to the output ground GND2.
[0013] The battery access protection circuit also includes a fuse F1; the positive terminal of the battery access port CAN1 is connected to the input terminal of the slow-start overvoltage protection circuit through the fuse F1.
[0014] With the above scheme, the working principle of the slow-start overvoltage protection circuit of this utility model is as follows: When the voltage of the battery connected to the positive and negative terminals of the battery input port CAN1 is high enough to break down the Zener diode D3, the battery voltage is too high. The breakdown of the Zener diode D3 causes the base voltage of the transistor Q3 to be pulled down, making the transistor Q3 conduct. The conduction of the transistor Q3 causes the gate voltage of the MOSFET Q1 to be pulled up, making the MOSFET Q1 turn off. In this way, the battery output voltage will not be output to the power supply output port VOUT, thereby realizing the overvoltage protection function. When the voltage of the battery connected to the positive and negative terminals of the battery input port CAN1 is not high enough to break down the Zener diode D3, the transistor Q3 is turned off and the MOSFET Q1 can conduct, so that the battery output voltage can be output to the power supply output port VOUT through the MOSFET Q1. Among them, the resistor R9 and the capacitor C3 can delay the conduction time of the transistor Q3 to achieve a slow-start effect. Attached Figure Description
[0015] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation
[0016] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.
[0017] like Figure 1 As shown, this utility model discloses a battery access protection circuit, which includes a battery access port CAN1, a slow-start overvoltage protection circuit, and a power output port VOUT; the battery access port CAN1 is connected to the power output port VOUT through the slow-start overvoltage protection circuit.
[0018] In an embodiment of this utility model, the slow-start overvoltage protection circuit includes resistors R3, R4, R5, R6, and R9, capacitor C3, Zener diode D3, transistor Q3, and MOSFET Q1; wherein, the first terminal of resistor R3, the emitter of transistor Q3, and the source of MOSFET Q1 are connected to the input terminal of the slow-start overvoltage protection circuit; the second terminal of resistor R3 is connected to the negative terminal of Zener diode D3 and the first terminal of resistor R5; the positive terminal of Zener diode D3 is connected to input ground GND1; and the second terminal of resistor R5 is connected to the first terminal of resistor R9, the first terminal of capacitor C3, and... The base and collector of transistor Q3 are connected to the second terminal of capacitor C3, the first terminal of resistor R4, and the first terminal of resistor R6. The second terminal of resistor R4 is connected to output ground GND2. The second terminal of resistor R6 is connected to the gate of MOSFET Q1. The drain of MOSFET Q1 and the second terminal of resistor R9 are connected to the output terminal of the soft-start overvoltage protection circuit. The positive terminal of battery input port CAN1 is connected to the input terminal of the soft-start overvoltage protection circuit, and the negative terminal of battery input port CAN1 is connected to input ground GND1. The power supply output port VOUT is connected to the output terminal of the soft-start overvoltage protection circuit.
[0019] The working principle of the slow-start overvoltage protection circuit is as follows: When the voltage of the battery connected to the positive and negative terminals of the battery input port CAN1 is high enough to break down the Zener diode D3, the battery voltage is too high. The breakdown of Zener diode D3 pulls down the base voltage of transistor Q3, causing Q3 to conduct. The conduction of transistor Q3 then pulls up the gate voltage of MOSFET Q1, causing Q1 to turn off. Thus, the battery output voltage will not be output to the power supply output port VOUT, achieving overvoltage protection. Conversely, when the voltage of the battery connected to the positive and negative terminals of the battery input port CAN1 is not high enough to break down Zener diode D3, transistor Q3 turns off, allowing MOSFET Q1 to conduct, enabling the battery output voltage to be output to the power supply output port VOUT through MOSFET Q1. Resistor R9 and capacitor C3 delay the conduction time of transistor Q3, achieving a slow-start effect.
[0020] In an embodiment of this invention, the slow-start overvoltage protection circuit may further include a capacitor C4 and a Zener diode D4. The first terminal of capacitor C4 and the negative terminal of Zener diode D4 are connected to the source of MOSFET Q1, and the second terminal of capacitor C4 and the positive terminal of Zener diode D4 are connected to the gate of MOSFET Q1. When the voltage of the battery connected to the positive and negative terminals of the battery input port CAN1 is insufficient to break down Zener diode D3, but the voltage of the battery is sufficient to break down Zener diode D4, the gate voltage of MOSFET Q1 is pulled high, causing MOSFET Q1 to turn off. This achieves a two-stage overvoltage protection function, making the overvoltage protection function of this invention more reliable.
[0021] In an embodiment of this utility model, the battery connection protection circuit of this utility model further includes a reverse connection protection circuit, and the input ground GND1 and the output ground GND2 are connected through the reverse connection protection circuit; the reverse connection protection circuit can disconnect the input ground GND1 and the output ground GND2 when the positive and negative terminals of the connected battery are incorrect, so that the battery connection protection circuit of this utility model will not form a loop, thereby providing the mains reverse connection protection function.
[0022] In an embodiment of this invention, the reverse connection protection circuit includes a resistor R2 and a MOSFET Q2. The first end of the resistor R2 is connected to the positive terminal of the battery access port CAN1, and the second end of the resistor R2 is connected to the gate of the MOSFET Q2. The drain of the MOSFET Q2 is connected to the input ground GND1, and the source of the MOSFET Q2 is connected to the output ground GND2. When the positive and negative terminals of the connected battery are correct, the current flows from the power supply output port VOUT of the battery access protection circuit to the load, and then through the output ground GND2 and the MOSFET Q2 to the input ground GND1. Specifically, at the moment of power-on, the output ground GND2 is first connected to the input ground GND1 through the body diode of the MOSFET Q2. Subsequently, the MOSFET Q2 turns on, making the output ground GND2 and the input ground GND1 stably connected. When the positive and negative terminals of the connected battery are incorrect, the current should be output from the input ground GND1, MOSFET Q2 and output ground GND2 to the load. However, at the moment of power-on, the current cannot pass through the body diode of MOSFET Q2 and MOSFET Q2 cannot pass through. Thus, there is no current loop in the entire circuit, which disconnects the load and realizes the reverse connection protection function.
[0023] In an embodiment of this invention, the reverse connection protection circuit further includes a Zener diode D2 and a capacitor C2. The first terminal of capacitor C2 and the negative terminal of Zener diode D2 are connected to the gate of MOSFET Q2, and the second terminal of capacitor C2 and the positive terminal of Zener diode D2 are connected to the source of MOSFET Q2. Zener diode D2 and capacitor C2 can limit the gate-source voltage of MOSFET Q2, thereby protecting MOSFET Q2.
[0024] In embodiments of this invention, the battery access protection circuit may further include a surge absorption circuit, which can absorb surge current and improve the EMI performance of the entire circuit. Specifically, the surge absorption circuit includes a bidirectional Zener diode D1, a resistor R1, and a capacitor C1. The first positive terminal of the bidirectional Zener diode D1 and the first end of the resistor R1 are connected to the positive terminal of the battery access port CAN1. The second end of the resistor R1 is connected to the first end of the capacitor C1. The first end of the capacitor C1 and the second positive terminal of the bidirectional Zener diode D1 are connected to the input ground GND1.
[0025] In embodiments of this utility model, the battery connection protection circuit may further include a connection indicator circuit, which indicates whether the battery is connected. Specifically, the connection indicator circuit includes a resistor R8 and an indicator light LED1. The first end of the resistor R8 is connected to the positive terminal of the battery connection port CAN1, the second end of the resistor R8 is connected to the positive terminal of the indicator light LED1, and the negative terminal of the indicator light LED1 is connected to the input ground GND1. When the battery is correctly connected, the indicator light LED1 lights up.
[0026] In embodiments of this invention, the battery access protection circuit may further include an output filter circuit. This output filter circuit can reduce the noise of the output voltage at the power supply output port VOUT and improve the stability of the output voltage. Specifically, the output filter circuit includes a resistor R7 and a capacitor C5. The first end of the resistor R7 is connected to the power supply output port VOUT, the second end of the resistor R7 is connected to the first end of the capacitor C5, and the second end of the capacitor C5 is connected to the output ground GND2.
[0027] In an embodiment of this utility model, the battery access protection circuit may further include a fuse F1; the positive terminal of the battery access port CAN1 is connected to the input terminal of the slow-start overvoltage protection circuit, the first terminal of the resistor R2 of the reverse connection protection circuit, the first positive terminal of the bidirectional Zener diode D1 of the surge absorption circuit and the first terminal of the resistor R1, and the first terminal of the resistor R8 connected to the indicator circuit through the fuse F1; the fuse F1 can play the role of overcurrent protection.
[0028] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.
Claims
1. A battery access protection circuit, characterized by: The battery access port CAN1, the slow start overvoltage protection circuit, and the power supply output port VOUT are included. The slow start overvoltage protection circuit includes resistors R3, R4, R5, R6, R9, a capacitor C3, a zener D3, a transistor Q3, and a MOS Q1. The first end of the resistor R3, the emitter of the transistor Q3, and the source of the MOS Q1 are connected to the input end of the slow start overvoltage protection circuit. The second end of the resistor R3 is connected to the negative electrode of the zener D3 and the first end of the resistor R5. The positive electrode of the zener D3 is connected to the input ground GND1. The second end of the resistor R5 is connected to the first end of the resistor R9, the first end of the capacitor C3, and the base of the transistor Q3. The collector of the transistor Q3 is connected to the second end of the capacitor C3, the first end of the resistor R4, and the first end of the resistor R6. The second end of the resistor R4 is connected to the output ground GND2. The second end of the resistor R6 is connected to the gate of the MOS Q1. The drain of the MOS Q1 and the second end of the resistor R9 are connected to the output end of the slow start overvoltage protection circuit. The positive electrode of the battery access port CAN1 is connected to the input end of the slow start overvoltage protection circuit, and the negative electrode of the battery access port CAN1 is connected to the input ground GND1. The power supply output port VOUT is connected to the output end of the slow start overvoltage protection circuit.
2. The battery access protection circuit of claim 1, wherein: The slow start overvoltage protection circuit further includes a capacitor C4 and a zener D4. The first end of the capacitor C4 and the negative electrode of the zener D4 are connected to the source of the MOS Q1. The second end of the capacitor C4 and the positive electrode of the zener D4 are connected to the gate of the MOS Q1.
3. The battery access protection circuit of claim 1, wherein: The reverse connection protection circuit is also included, and the input ground GND1 and the output ground GND2 are connected through the reverse connection protection circuit. The reverse connection protection circuit includes a resistor R2 and a MOS Q2. The first end of the resistor R2 is connected to the positive electrode of the battery access port CAN1. The second end of the resistor R2 is connected to the gate of the MOS Q2. The drain of the MOS Q2 is connected to the input ground GND1. The source of the MOS Q2 is connected to the output ground GND2.
4. The battery access protection circuit of claim 3, wherein: The reverse connection protection circuit further includes a zener D2 and a capacitor C2. The first end of the capacitor C2 and the negative electrode of the zener D2 are connected to the gate of the MOS Q2. The second end of the capacitor C2 and the positive electrode of the zener D2 are connected to the source of the MOS Q2.
5. The battery access protection circuit of claim 1, wherein: The surge absorption circuit is also included. The surge absorption circuit includes a bidirectional zener D1, a resistor R1, and a capacitor C1. The first positive electrode of the bidirectional zener D1 and the first end of the resistor R1 are connected to the positive electrode of the battery access port CAN1. The second end of the resistor R1 is connected to the first end of the capacitor C1. The first end of the capacitor C1 and the second positive electrode of the bidirectional zener D1 are connected to the input ground GND1.
6. The battery access protection circuit of claim 1, wherein: The access indication circuit is also included. The access indication circuit includes a resistor R8 and an indicator LED1. The first end of the resistor R8 is connected to the positive electrode of the battery access port CAN1. The second end of the resistor R8 is connected to the positive electrode of the indicator LED1. The negative electrode of the indicator LED1 is connected to the input ground GND1.
7. The battery access protection circuit of claim 1, wherein: The output filter circuit further comprises a resistor R7 and a capacitor C5, a first end of the resistor R7 is connected to the power output port VOUT, a second end of the resistor R7 is connected to a first end of the capacitor C5, and a second end of the capacitor C5 is connected to the output ground GND2.
8. The battery access protection circuit of claim 1, wherein: The fuse F1 is further included, and a positive electrode of the battery access port CAN1 is connected to the input end of the slow start overvoltage protection circuit through the fuse F1.