Patent ID: 7508254

Claim:
A reference supply voltage circuit for generating a second reference voltage based on a first reference voltage generated by an electric power supplying circuit, and supplying the second reference voltage to an operation circuit, said reference supply voltage circuit comprising: a detecting device for detecting the first reference voltage; a comparator for outputting a signal which controls an operation state and a stop state of the operation circuit by comparing the first reference voltage detected by said detecting device with a predetermined reference detection voltage; and a circuit for preventing any false operation during a pre-operation indefinite time interval for inputting the first reference voltage, for maintaining the second reference voltage at a zero voltage when the first reference voltage is lower than a first predetermined voltage, for setting the second reference voltage to a voltage equal to the first reference voltage when the first reference voltage is equal to or higher than the first predetermined voltage and lower than a second predetermined voltage, for setting the second reference voltage to a voltage proportional to the first reference voltage when the first reference voltage is equal to or higher than the second predetermined voltage, and for supplying the second reference voltage to the operation circuit.