Reference current source circuit

Claim 1

A current source circuit comprising: a first circuit including first and second terminals, first and second transistors of the same conductivity type having different emitter areas, bases of said first and second transistors being connected with each other and one of said first and second transistors being diode-connected, and an emitter resistor connected to an emitter of one of said first and second transistors having greater emitter area, so that first and second currents of the same magnitude depending on the emitter area ratio between said first and second transistors and the resistance value of said emitter resistor may be caused to flow into said first circuit through said first and second terminals; an output transistor coupled to said first circuit for providing an output current; and a second circuit for allowing to provide said first and second currents at said first and second terminals of said first circuit, characterized in that said second circuit includes first and second constant current sources having outputs coupled respectively to said first and second terminals of said first circuit and providing at said outputs third and fourth currents of the same magnitude greater than that of said first and second currents, and a current mirror coupled to said outputs of said first and second current sources.