Patent ID: 7233136
Filing Date: 2007-06-19
Classification: G05F

Abstract:
1. A reference voltage circuit for outputting a stable reference voltage comprising: a first semiconductor inserted in a forward direction with respect to a negative power supply line of a power source voltage and a second semiconductor inserted in the forward direction with respect to the negative power supply line, wherein each of the first and second semiconductors comprises a PN junction; an operational amplifier connected to a positive power supply line and the negative power supply line of the power source voltage, wherein one end of a first resistor is connected to an output terminal of the operational amplifier and an other end of the first resistor is connected to a non-inverting input terminal of the operational amplifier, one end of a second resistor is connected to the output terminal of the operational amplifier and an other end of the second resistor is connected to an inverting input terminal of the operational amplifier, one end of a third resistor is connected to the inverting input terminal of the operational amplifier and an other end of the third resistor is connected to the second semiconductor; and a fourth resistor having one end connected to the non-inverting input terminal of the operational amplifier and an other end connected to the first semiconductor, wherein a resistance value of the fourth resistor is set to be smaller than a resistance value of the first resistor.