Substrate based temperature sensing

1. A method of accurately sensing the temperature of a substrate having a sensing transistor formed therein, comprising:

providing a first emitter drive current, I E1 :

recording a first base current, I B1 :

recording a first base emitter voltage, V be1 :

determining a base current, MI B1 , M being a predetermined multiple:

providing an emitter drive current, MI E1 :

recording the base current, I B2 , resulting from said emitter drive current:

provide a second emitter drive current that is the summation of I B3 −MI B1 and MI E1 :

recording a second base emitter voltage, V be3

determining ΔV be =V be2 −V be1 :

computing the junction temperature of said sensing transistor by utilizing ΔV be.

2. An arrangement for measuring the temperature of a substrate, comprising:

a sensing transistor on said substrate;

a sensing and control circuit coupled to said transistor, said sensing and control circuit operating said transistor under first drive conditions to produce a first response and operating said transistor under second drive conditions having a predetermined relationship to said first drive conditions to produce a second response, said sensing and control circuit utilizing said first and said second in accordance with a predetermined algorithm to determine the temperature of said substrate;

said sensing and control circuit providing a first emitter drive current and recording a corresponding first base current and a corresponding first base emitter voltage, and providing an emitter drive current which is a predetermined multiple, M, of said first emitter drive current and recording a corresponding second base current; and providing a second emitter drive current that is the summation of said emitter drive current and the second base current minus the multiple, M times the first base current and recording a corresponding resulting second base emitter voltage:

determining a voltage differential that is the difference between said first base emitter voltage and said second base emitter voltage V be2 ; and

determining the junction temperature of said sensing transistor from said voltage difference in accordance with said predetermined algorithm.