Patent ID: 8283981

Claim:
An operational amplifier for amplifying difference signals that indicate a difference value between levels of the first and second input signals and outputting first and second amplified difference signals having different polarities, comprising: level shift portions which produce as drive signals signals obtained by level shifting said difference signals by predetermined values; a push-pull amplification circuits which produce said first amplified difference signal and said second amplified difference signal in accordance with said drive signals; a common mode voltage adjustment signal generating portion which generates a common mode voltage adjustment signal indicating a difference between a center value of said first and second amplified difference signals and a common mode reference voltage value; common mode voltage adjusting transistors each of which is connected in parallel to a low voltage side drive transistor of each of said push-pull amplification circuit and allows a flow of a current according to said common mode voltage adjustment signal; auxiliary drive transistors each of which is connected in parallel to a low voltage side drive transistor of each of said push-pull amplification circuit and allows a flow of a current according to an auxiliary drive signal; and auxiliary drive control portions each of which alternately supplies said signal obtained by level shifting said difference signal and said common mode voltage adjustment signal to said auxiliary drive transistor as said auxiliary drive signal.