Patent ID: 8324968

Claim:
An amplifier circuit comprising: differential input transistors forming a differential pair; a current supply circuit that supplies a predetermined current to the differential input transistors; a load circuit that is switchable between a first state and a second state, the load circuit functioning as an active load on the differential input transistors in the first state and functioning as a load on the differential input transistors in the second state; a load switching circuit that switches the load circuit to the first state when a first switching signal is supplied and switches the load circuit to the second state when a second switching signal is supplied; and an output switching circuit that causes a differential amplification signal produced through one of common connection nodes between the differential input transistors and the load circuit to be outputted when the first switching signal is supplied and causes the differential amplification signal produced through both of the common connection nodes between the differential input transistors and the load circuit to be outputted when the second switching signal is supplied.