Protection circuit capable of preventing wrong voltage access

Abstract

A protection circuit capable of preventing wrong voltage access comprises a voltage input end, a voltage output end, a first one-way conduction element, a triode control circuit, a first triode, a first capacitor, a Darlington tube, a first resistor, a second resistor and a relay. And a relay contact is connected in series between the voltage input end and the voltage output end. The first end of the first one-way conduction element is connected with the voltage input end, and the second end of the first one-way conduction element is connected with the first resistor, the first triode, the first capacitor and the first end of the Darlington tube. The first conduction end of the triode control circuit is connected with the second end of the first resistor and the controlled end of the first triode, and the second conduction end is grounded. The first end of the second resistor is connected to a common connection point of the second end of the first triode, the second end of the first capacitor and the controlled end of the Darlington tube, and the second end of the second resistor is grounded; the second end of the Darlington tube is connected with the controlled end of the relay. The circuit is low in cost, and can cut off the connection from the input end to the output end when wrong voltage is input.

Description

technical field [0001] The invention relates to protection circuit technology. Background technique [0002] With the development of intelligence and electrification of automobiles, there are more and more cases of overlapping power supply, and it has become a common phenomenon to use mains power and high-voltage direct current to charge automobiles. The power interface on many cars is a low-voltage power interface with a working voltage of 12V or 24V. When such as high-voltage direct current, alternating current (including mains power) is mistakenly connected to the low-voltage power interface, if there is no wrong voltage protection, the car will be damaged. The internal low-voltage controller and low-voltage electrical appliances are damaged or even caught fire. Port protection devices currently on the market, such as varistors, TVS diodes, fuses, etc., can only protect short-term surge voltages, but cannot protect high-voltage DC voltages and high-voltage AC voltages th...

AI Technical Summary

Problems solved by technology

The power interface on many cars is a low-voltage power interface with a working voltage of 12V or 24V. When such as high-voltage direct current, alternating current (including mains power) is mistakenly connected to the low-voltage power interface, if there is no protection for wrong voltage connection, it will cause damage to the car. The internal low-voltage controller and low-voltage electrical appliances are damaged or even caught fire

Port protection devices currently on the market, such as varistors, TVS diodes, fuses, etc., can only protect short-term surge voltages, and cannot protect high-voltage DC voltages and high-voltage AC voltages that have been misconnected for a long time

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