Patent ID: 7414464

Claim:
An operational amplifier driver capable of canceling an offset voltage of an operational amplifier, the operational amplifier having a chopper, a first input terminal, a second input terminal and an output terminal, the operational amplifier driver comprising: a first switch having a first terminal and a second terminal, wherein the first terminal receives an input voltage and the second terminal is connected to the first input terminal of the operational amplifier; a second switch connected to the first input terminal of the operational amplifier and the output terminal of the operational amplifier; a third switch connected to the second input terminal of the operational amplifier and the output terminal of the operational amplifier; and a capacitor connected to the second input terminal of the operational amplifier; wherein: in an input voltage storing stage, the first switch and the third switch are turned on, the second switch is turned off, the first input terminal is switched to a positive input terminal, and the second input terminal is switched to a negative input terminal; and in a voltage outputting stage, the first switch and the third switch are turned off, the second switch is turned on, the first input terminal is switched to the negative input terminal, and the second input terminal is switched to the positive input terminal.