Patent ID: 7766546

Claim:
A method for use in measuring a temperature of a bi-polar measurement transistor, said method comprising: (a) providing a controller; (b) providing a first emitter current to an emitter terminal of the measurement transistor in response to the controller, with the first emitter current resulting in a first base current and a first collector current in the measurement transistor; (c) sensing the first base current at a base terminal of the measurement transistor; (d) sensing a base-emitter voltage of the measurement transistor when the measurement transistor is conducting the first emitter current; (e) providing a second emitter current to the measurement transistor emitter terminal in response to the controller, with the second emitter current resulting in a second base current and a second collector current in the measurement transistor and wherein the first and second emitter currents differ in magnitude; (f) sensing the second base current at the base terminal of the measurement transistor; (g) sensing a second base-emitter voltage of the measurement transistor when the measurement transistor is conducting the second emitter current; (h) establishing a magnitude ratio N of the first and second collector currents utilizing at least the sensed first and second base currents; and (i) determining the temperature of the measurement transistor based, at least in part, on the ratio N and a difference between the first and second base-emitter voltages.