Vehicle voltage-stabilizing circuit

The utility model provides a vehicle voltage-stabilizing circuit comprising a voltage converting circuit, a switch circuit, and a pulse width modulator, wherein the voltage converting circuit is used for boosting and stabilizing voltage output by a vehicle-mounted low voltage battery when an engine is started, the switch circuit is used for transmitting energy of the low voltage battery to a load when a vehicle is in a normal state, the pulse width modulator is used for driving and control work of the voltage converting circuit which is connected between the low voltage battery and the load, a controlled end of the voltage converting circuit is electrically connected with the pulse width modulator, switch circuit is connected between the low voltage battery and the load, and a controlled end of the switch circuit is electrically connected with a start and stop signal output end of the engine. The vehicle voltage-stabilizing circuit provided by the utility model can enable a vehicle-mounted load to obtain a stable and reliable low voltage source all the time, and therefore a vehicle-mounted low voltage electric appliance is enabled to work in a normal and stable manner all the time.