Patent ID: 7911244

Claim:
A differential drive circuit comprising at least one of: a first drive system including a first field effect transistor of a first conductivity type, a second field effect transistor of the first conductivity type, a first resistor and a second resistor, a first circuit that uses negative feedback to control a source voltage of the first field effect transistor so as to be equal to a first drive target voltage that is supplied, and a second circuit that uses negative feedback to control a source voltage of the second field effect transistor so as to be equal to a second drive target voltage that is supplied, the first field effect transistor having a source connected to a power supply potential source via the first resistor, and a drain connected to a first output node, the second field effect transistor having a source connected to the power supply potential source via the second resistor, and a drain connected to a second output node; and a second drive system including a third field effect transistor of a second conductivity type, a fourth field effect transistor of the second conductivity type, a third resistor and a fourth resistor, a third circuit that uses negative feedback to control a source voltage of the third field effect transistor so as to be equal to a third drive target voltage that is supplied, and a fourth circuit that uses negative feedback to control a source voltage of the fourth field effect transistor so as to be equal to a fourth drive target voltage that is supplied, the third field effect transistor having a source connected to a reference potential source via the third resistor, and a drain connected to the first output node, the fourth field effect transistor having a source connected to the reference potential source via the fourth resistor, and a drain connected to the second output node, wherein the differential drive circuit drives a common-mode voltage so as to form a constant differential signal across a load resistance.