US Patent 7663440 Amplifier circuit, semiconductor device, and controlling method

An amplifier circuit including a plurality of CMOS (Complementary Metal Oxide Semiconductor) inverter circuits connected in parallel with each other. The CMOS inverter circuits each include a first PMOS (P-channel Metal Oxide Semiconductor) transistor, a first NMOS (N-channel Metal Oxide Semiconductor) transistor, gates of the first PMOS and NMOS transistors, a second PMOS transistor, a first switch connected to a gate of the second PMOS transistor, a second NMOS transistor, and a second switch connected to a gate of the second NMOS transistor.