Power supply overvoltage and undervoltage protection circuit for vehicle-mounted electronic equipment

The utility model discloses a power supply overvoltage and undervoltage protection circuit for vehicle-mounted electronic equipment. The power supply overvoltage and undervoltage protection circuit comprises a P2576L switching power supply chip N1, a PNP crystal triode VT1, a PNP crystal triode VT2, an NPN crystal triode VT3, an NPN crystal triode VT4, a Zener diode VD2, a Zener diode VD3, a diode VD1, a diode VD5 and a TVS tube VD6. Through the design that the overvoltage and undervoltage protection circuit is additionally arranged on the power supply of the vehicle-mounted electronic and electrical equipment, firstly, the power supply is used for protecting a post-stage circuit from being damaged by instant overhigh voltage; and secondly, the device is used for protecting the automobile storage battery, so that the automobile storage battery cannot be damaged due to over-discharge. The design is efficient, flexible and simple, and therefore the design requirements for miniaturization and simplification of e