Patent ID: 7304511

Claim:
An output circuit for supplying a voltage within a potential range, said output circuit comprising: a power supply terminal; a ground terminal; an output teminal for connection with an external power supply voltage, the potential range being determined by a potential of the power supply terminal and a potential of the ground terminal, the output circuit supplying the voltage from the output terminal; a first transistor having one main electrode connected to the power supply terminal and another main electrode connected to the output terminal; a second transistor having one main electrode connected to a control electrode of the first transistor and another main electrode connected to the output terminal; and an earth circuit connected to the control electrode of the first transistor for removing charges stored on the control electrode of the first transistor, wherein the second transistor is turned on when the voltage of the output terminal is beyond the potential range, wherein the first transistor is turned off when the voltage of the output terminal is introduced to the control electrode of the first transistor upon turning on of the second transistor, and wherein the earth circuit includes: a resistor connected to the ground terminal; a third transistor having one main electrode connected to the control electrode of the first transistor and a control electrode connected to the power supply terminal; and a fourth transistor having one main electrode connected to the third transistor, another main electrode connected to the resistor and a control electrode connected to the power supply terminal.