Patent ID: 6806770
Filing Date: 2004-10-19
Classification: H03F

Abstract:
An operational amplifier for use with high and low potential power supplies and for receiving an input current, the operational amplifier comprising:a first output transistor connected to the high potential power supply and having a control terminal; a second output transistor connected between the first output transistor and the low potential power supply and having a control terminal, with an output voltage being available at an output node between the first output transistor and the second output transistor; and a drive unit connected to the first and second output transistors to drive the first and second output transistors in accordance with the input current, wherein the drive unit including: a current source connected to the high potential power supply; a first current mirror circuit connected to the current source; and a second current mirror circuit connected between the first current mirror circuit and the low potential power supply; wherein the input current is supplied to a first node between the first and second current mirror circuits, the control terminal of the second output transistor is connected to the first node, and the control terminal of the first output transistor is connected to a second node between the current source and the first current mirror circuit.