Patent ID: 7342449

Claim:
A differential amplifier comprising: a plurality of differential pairs of a first conductivity type and a plurality of differential pairs of a second conductivity type, each of said differential pairs of the first and second conductivity type having one of an input pair thereof constituting an input terminal, said differential amplifier being capable of performing output from an output terminal thereof over a full range between first and second power supply voltages supplied to said differential amplifier; a determination unit receiving at least one signal for determination and determining whether to stop operation of said differential pairs of said first conductivity type or operation of said differential pairs of said second conductivity type based at least upon a voltage characteristic of the at least one signal; and a differential pair control unit receiving a result of determination by said determination unit and switching between a first state and a second state according to the result of the determination, said first state making said differential pairs of said first conductivity type active, while making said differential pairs of said second conductivity type inactive, said second state making said differential pairs of said first conductivity type inactive, while making said differential pairs of said second conductivity type active, wherein the first state, said output terminal is driven only by said differential pairs of the first conductivity type and in the second state said output terminal is driven only by said differential pairs of the second conductivity type.