Patent ID: 8031000

Claim:
A differential amplifier comprising; a first amplifier which is provided with a first input terminal; a second amplifier which is provided with a second input terminal; and a common-mode feedback circuit that feeds back signal corresponding to common-mode components of output terminal voltage of the first and second amplifiers to the first and the second input terminals via first and second passive elements connected to a common terminal, respectively, wherein the common-mode feedback circuit comprises: a common-mode detection circuit that detects common mode components of the output terminal voltage of the first and second amplifiers, and a control circuit that outputs to the common terminal a control signal generated based on common-mode components detected by the common-mode detection circuit, and outputs the control signal from the common terminal to the input terminals of the first and second amplifiers via the first and second passive elements, respectively, wherein the common-mode detection circuit comprises: a first resistor connected between the output terminal of the first amplifier and the output terminal of the common-mode detection circuit, a second resistor connected between the output terminal of the second amplifier and the output terminal of the common-mode detection circuit, a first buffer inserted between the output terminal of the first amplifier and the first resistor, and a second buffer inserted between the output terminal of the second amplifier and the second resistor.