Substrate based temperature sensing
View Patent ↗A method for providing accurate temperature sensing of a substrate utilizing the PN junction of a transistor formed on the substrate is described.
1. A method of accurately sensing the temperature of a substrate having a sensing transistor formed therein, comprising:
providing a first voltage to the emitter of said transistor;
current driving the base of said transistor with a first current, I B1 ;
measuring a first base emitter voltage, V be1 ;
current driving the base of said transistor with a second current I B2 such that I B2 /I B1 =M;
measuring a second base emitter voltage, V be2; and
determining the temperature utilizing the relationship
ΔV be =ηKT/q ln I B2 /I B1 .
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 base current drive conditions to produce a first response and operating said transistor under second base current drive conditions having a predetermined relationship to said first base current drive conditions to produce a second response, said sensing and control circuit utilizing only said first and said second responses in accordance with a predetermined algorithm to determine the temperature of said substrate.