Patent ID: 7279942

Claim:
A differential current output unit, comprising: a difference input circuit that includes first and second current mirror source transistors for respectively outputting a first and a second mirror source voltage in response to a differential input voltage inputted to said difference input circuit; a current subtraction circuit for outputting current in accordance with the difference in current between a first mirror current outputted from a first transistor first mirror target transistor in response to said first mirror source voltage and a second mirror current outputted from a second transistor second mirror target transistor in response to said second mirror source voltage; a delivery circuit for generating and delivering current output instruction signals in accordance with the magnitude and polarity of said difference current; and a current output circuit having a plurality of output transistor circuits each including a third mirror source transistor that is enabled by one of said current output instruction signals and a third mirror target transistor for flowing therethrough current in accordance with the current that flows through said third mirror source transistor, wherein said current output circuit is adapted to provide a load with positive or negative output current in accordance with the polarity and magnitude of said current output instruction signals.