CMOS voltage and current reference circuit

Claim 1

A CMOS current reference capable of conducting an output current having a value proportional to absolute temperature, said circuit comprising: first and second supply terminals connectable to a source of operating power; a first bipolar transistor having a collector connected to said first supply terminal, a base connected to a reference potential and an emitter coupled to said second supply terminal by way of a first constant current device; a second bipolar transistor having a collector connected to said first terminal, a base coupled to said base of said first bipolar transistor through a first resistor, and an emitter coupled to said second supply terminal by way of a second constant current device; means for ratioing the current densities in said first and second bipolar transistors so that said first bipolar transistor conducts a multiple of the current density of said second bipolar transistor; a field effect transistor having a source coupled to said base of said second bipolar transistor, a drain coupled to conduct said output current, and a gate; and a differential amplifier having an output coupled to said gate of said field effect transistor, a non-inverting input coupled to said emitter of said first bipolar transistor and an inverting input coupled to said emitter of said second bipolar transistor whereby said differential amplifier drives said base of said second bipolar transistor, by way of said field effect transistor acting as a source follower, to force said emitters of said first and second bipolar transistors to the same potential so that the differential base to emitter voltage (ΔV BE ) of said first and second bipolar transistors appears across said first resistor.