Patent ID: 7053695

Claim:
An amplifier comprising: a reference current source supplying a reference current; a first transistor connected in series to the reference current source, and converting the reference current into a voltage; a second transistor having a current mirror relationship with the first transistor, and allowing a first current to pass therethrough; a third transistor having a current mirror relationship with the first transistor, and allowing a second current to pass therethrough; a first differential amplifier operated using the first current flowing through the second transistor as one supply current, and receiving a voltage supplied to an input terminal; an error amplifier receiving an output voltage of the first differential amplifier at the one input terminal, and comparing the voltage at the one input terminal with a voltage supplied to the other input terminal to output an error voltage; a voltage source supplying a voltage to the other input terminal of the error amplifier; a fourth transistor operating the first differential amplifier, using a third current driven to flow with an output voltage of the error amplifier as the other supply current; a fifth transistor driven with the output voltage of the error amplifier, and allowing a fourth current to pass therethrough; and a second differential amplifier operated using the second current flowing through the third transistor as one supply current and using the fourth current flowing through the fifth transistor as the other supply current, and amplifying a voltage supplied to the input terminal.