Temperature sensing device

Claim 1

Digital output temperature sensing device, comprising identical first and second transistors in an integrated circuit, said transistors each including a base, an emitter and a collector, means for applying different base-emitter voltages across the first and second transistors for passing a first collector-emitter current through the first transistor and a second collector-emitter current through the second transistor, the second current being a function of the first current and of the absolute temperature, means for supplying a third current as a function of the first current independent of the absolute temperature, the second and third currents being equal at a given absolute temperature, said means for supplying said third current including a pair of transistors of opposed type to the first and second transistors, said pair of transistors having base-emitter junctions with different effective injection surface areas and otherwise being identical with one another, and means for supplying a digital output signal according to whichever of the second and third currents is greater.