Monitoring circuit of 12V voltage in electric vehicle electric drive controller

The invention discloses a monitoring circuit of 12V voltage in an electric vehicle electric drive controller. The monitoring circuit is characterized by comprising a voltage reference setting circuit which is used for setting an overvoltage threshold and an undervoltage threshold of the 12V voltage; a voltage comparison circuit which divides voltage of a 12V storage battery to obtain a voltage detection signal, then compares the voltage detection signal with the overvoltage threshold and the undervoltage threshold, and outputs a low electrical level fault signal when the voltage detection signal exceeds the overvoltage threshold or the undervoltage threshold; and an optical coupler isolation circuit which converts an electrical level of the low electrical level fault signal output by the voltage comparison circuit in isolation, then obtains an electrical level signal compatible with a digital signal processor (DSP) main control chip, and transmits the electrical level signal to the DSP main control chip. The monitoring circuit outputs the low electrical level fault signal when storage battery voltage is over or below given thresholds, and transmits the low electrical level fault signal to the DSP main control chip so as to obtain protection for a controller.