Patent ID: 7176701

Claim:
A temperature sensor comprising first and second transistors having different emitter current densities and a feedback circuit for controlling collector voltages and emitter currents of the first and second transistors such that the collector voltages of the first and second transistors vary with similar temperature responses, the temperature sensor detecting temperature by exploiting a phenomenon in which a difference between base-emitter voltages of the first and second transistors varies according to temperature, wherein the feedback circuit comprises: a first current mirror circuit composed of a third transistor through an emitter of which flows an emitter current commensurate with the collector voltage of the first transistor and a fourth transistor through an emitter of which flows an emitter current commensurate with the collector voltage of the second transistor, the emitter current of the fourth transistor being varied so as to follow variation of the emitter current of the third transistor; and a second current mirror circuit of which an operating voltage is determined so as to follow variation of the emitter current of the fourth transistor, the second current mirror circuit determining the emitter currents of the first and second transistors.