A high voltage interlocking circuit of new energy vehicles and a fault diagnosis method

The invention provides a high voltage interlocking circuit of new energy vehicles. A signal generating circuit generates PWM signals according to the control of a main control chip. A first voltage comparator transmits a first comparison result of the voltage of a second end of a first resistor to the main control chip. A second voltage comparator transmits a second comparison result of the voltage of the second end of the first resistor to the main control chip. As the output end of the high voltage interlocking circuit, a second end of a second resistor is connected with a high voltage interlocking loop of a whole vehicle system and, as the input end of the high voltage interlocking circuit, a second end of a third resistor is connected with the high voltage interlocking loop of the whole vehicle system, so that the high voltage interlocking loop can generate PWM signals through the control of the main control chip and the main control chip determines the condition of the high voltage interlocking loop according to the first comparison result and a second comparison result. The invention also provides a fault diagnosis method based on the circuit.