Patent ID: 7960960

Claim:
An irregular voltage detection and cutoff circuit, which monitors an operating voltage range of a power-supply voltage, the irregular voltage detection and cutoff circuit comprising: a bandgap reference voltage generation circuit, which generates a bandgap reference voltage from the power-supply voltage; a reference voltage generator, which generates a first reference voltage at a same voltage level as the bandgap reference voltage, and a second reference voltage; a voltage detector, which generates a detection voltage from the power supply voltage; and a comparator, which generates a switching control signal that cuts off the power-supply voltage by comparing the first and second reference voltages with the detection voltage, wherein the reference voltage generator comprises: an OP amp, wherein bandgap reference voltage is inputted to a non-inverting input terminal thereof and the first reference voltage is inputted to an inverting input terminal thereof; a PMOS transistor, whose gate is connected to an output of the OP amp, whose source is connected to the power-supply voltage, and whose drain is connected to the first reference voltage: a first resistor, which is connected between the first reference voltage and the second reference voltage; and a second resistor, which is connected between the second reference voltage and a ground voltage.