US Patent 7863970 Current source device

A current source device having a plurality of current output circuits each including a current output FET, first and second switch FETs respectively series-connected to source and drain sides of the current output FET to form a series circuit, a source voltage supply which applies a positive-side potential of a source voltage to the first switch FET and applies a negative-side potential of the source voltage to the second switch FET to supply the source voltage to the series circuit, and an output terminal connected between the current output FET and the second switch FET; and a gate voltage supply circuit which supplies a common gate voltage to the gates of the current output FETs, wherein each of the current output circuits further includes a third switch FET provided between the current output FET and the second switch FET.