一种用于常输出充电适配器的保护电路

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By incorporating a protection circuit in the adapter, which utilizes components such as resistors, Zener diodes, and comparators to detect reverse battery connection and quickly shut down the circuit, the protection problem of a constant output charging adapter when the battery is reverse connected is solved, achieving safe protection within 2µs.

CN224520660UActive Publication Date: 2026-07-17

Patent Information

Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Filing Date: 2025-08-19
Publication Date: 2026-07-17

AI Technical Summary

Technical Problem

Existing constant output charging adapters have a slow response time when the battery is reverse-connected, which can damage the adapter and lacks effective reverse-connection protection.

Method used

A protection circuit is set between the negative terminal of the transformer and the negative terminal of the battery in the adapter. This circuit includes components such as a first resistor, a Zener diode, a comparator, and a P-type MOSFET. It achieves rapid protection by quickly detecting the reverse connection voltage of the battery and controlling the optocoupler to shut down the circuit.

Benefits of technology

When the battery is reversed, the protection circuit can react within 2µs to prevent damage to the adapter and ensure safe use of the adapter under various operating conditions.

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Abstract

本实用新型涉及集成电子电路领域，特别涉及一种常输出充电适配器电路，包括在适配器中变压器的负极与电池负极之间设置保护电路，保护电路包括第一稳压二极管、第二稳压二极管、稳压器、第一电阻、第二电阻、第三电阻、第四电阻、第五电阻、第六电阻、第七电阻、第八电阻、第九电阻、电容、第一比较器、第二比较器以及P型MOS管，第一电阻的一端、第二电阻的一端与电池组的负极汇总端连接，第一电阻的另一端与第九电阻的一端、第二二极管的输入端、光耦控制端、隔离后侧的接地端以及第一比较器的正相调节端连接；本实用新型能在各种工况下对电池反接进行保护，保证适配器在各种工况下使用安全，实现对异常故障的保护，保证适配器更安全。

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Claims

1. A protection circuit for a constant output charging adapter, characterized by, A protection circuit is added across the first resistor (R27) placed between the negative terminal CHAR- of the transformer and the negative terminal of the battery in the adapter. The protection circuit includes a first Zener diode (D17), a second Zener diode (D19), a voltage regulator (Z1), a first resistor (R27), a second resistor (R32), a third resistor (R46), a fourth resistor (R48), a fifth resistor (R49), a sixth resistor (R50), a seventh resistor (R51), an eighth resistor (R52), a ninth resistor (R53), a capacitor (C25), a first comparator (IC4A), a second comparator (IC4B), and a P-type MOSFET (Q7). One end of the first resistor (R27) and one end of the second resistor (R32) are connected to the negative terminal PACK- of the battery pack. The other end of the first resistor (R27) is connected to one end of the ninth resistor (R53), the ground terminal IOS_GND on the isolated side, and the positive phase adjustment terminal of the first comparator (IC4A). The other end of the ninth resistor (R53) is connected to one end of the sixth resistor (R50), the non-inverting input of the first comparator (IC4A), and the inverting input of the second comparator (IC4B); the other end of the second resistor (R32) is connected to the inverting input of the first comparator (IC4A); the output of the first comparator (IC4A) is connected to the output of the second diode (D19) and the voltage protection terminal; the input of the second diode (D19) is connected to the optocoupler control terminal. The other end of the sixth resistor (R50) is connected to the output and adjustment terminals of the first Zener diode (D17), one end of the fourth resistor (R48), and the 2.5V threshold voltage terminal Fault_Vref_2V5; the input terminal of the first Zener diode (D17) is connected to the ground terminal IOS_GND on the isolation side. The other end of the fourth resistor (R48) is connected to one end of the capacitor and the 10V fault reference voltage power supply terminal S_Vcc_10V; the other end of the capacitor is connected to the ground terminal IOS_GND on the isolation side. The output of the second comparator (IC4B) is connected to the voltage protection terminal; the non-inverting input of the second comparator (IC4B) is connected to one end of the third resistor (R46) and one end of the seventh resistor (R51); The other end of the third resistor (R46) is connected to the 10V fault reference voltage power supply terminal; the other end of the seventh resistor (R51) is connected to the drain of the P-type MOSFET (Q7); the source of the MOSFET (Q7), one end of the eighth resistor (R52), and the ground terminal IOS_GND on the isolation side are connected together; the gate of the MOSFET (Q7) is connected to the other end of the eighth resistor (R52) and one end of the fifth resistor (R49); The input terminal of the second Zener diode is connected to the other end of the fifth resistor (R49), and the output terminal is connected to the charging output terminal.

2. The protection circuit for a constant output charging adapter according to claim 1, wherein, When the battery is reversed, the voltage at the end of the first resistor (R27) connected to the negative terminal PACK- of the battery pack is higher than the voltage at the end connected to the ground terminal IOS_GND on the isolated side. The voltage enters the inverting input terminal of the first comparator (IC4A) through the second resistor (R32). When the voltage at the inverting input terminal of the first comparator (IC4A) is higher than the reference voltage, the first comparator (IC4A) outputs a low level and controls the optocoupler control terminal through the second Zener diode (D19).

3. The protection circuit for a constant output charging adapter according to claim 1, wherein, The first resistor (R27) is 0.1 ohms, and the reference voltage is 0.3 volts.

4. The protection circuit for a constant output charging adapter according to claim 1, wherein, When the battery is reversed, the voltage at the positive input of the second comparator (IC4B) is lower than the reference voltage, and the second comparator (IC4B) outputs a low level to quickly shut down the reverse connection circuit.

5. The protection circuit for a constant output charging adapter according to claim 1, wherein, The first and second comparators are selected as LM393BIDDFR.

6. The protection circuit for a constant output charging adapter according to claim 1, wherein, The voltage regulator selected is ATL431BIDBZT.

7. The protection circuit for a constant output charging adapter according to claim 1, wherein, The first and second Zener diodes are selected as 1N4148W.

8. A protection circuit for a constant output charging adapter according to claim 1, characterized in that, The P-type MOSFET selected is the Si2309CDS.

9. The protection circuit for a constant output charging adapter according to claim 1, wherein, The capacitance value is 0.1uF.

10. The protection circuit for a constant output charging adapter according to claim 1, wherein, The second resistor has a resistance of 1000 ohms, the third resistor has a resistance of 10000 ohms, the fourth resistor has a resistance of 4700 ohms, the fifth resistor has a resistance of 200000 ohms, the sixth resistor has a resistance of 22000 ohms, the seventh resistor has a resistance of 22000 ohms, the eighth resistor is a thermistor with a resistance of 150 ohms, and the ninth resistor has a resistance of 3000 ohms.