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Transistor with Small Temperature Dependence

IP.com Disclosure Number: IPCOM000096993D
Original Publication Date: 1962-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Yhap, EF: AUTHOR

Abstract

By the incorporation of one or two diodes in transistor circuitry, it is possible to compensate for temperature effects on current flow. It is possible to compensate for the effect of the current Ico, collector current with a floating base, which flows through the collector by introducing another Ico source which counteracts the first.

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Transistor with Small Temperature Dependence

By the incorporation of one or two diodes in transistor circuitry, it is possible to compensate for temperature effects on current flow. It is possible to compensate for the effect of the current Ico, collector current with a floating base, which flows through the collector by introducing another Ico source which counteracts the first.

Temperature compensating diode 12 is required to have characteristics such that its reaction to temperature is substantially the same as that of transistor 10. It is also necessary that at a temperature T, the current flowing through the diode is V/R = Ico (diode) =~ Ico (transistor). R is the resistance of the diode and V is the voltage from emitter to base. Since both transistor and diode react similarly to temperature variations, any increase in temperature causes an equal incremental rise of current through both components. However, due to their direction they will tend to nullify each other. To simplify the matching of the transistor and the temperature compensating diode, the diode and transistor are grown at the same time on the same substrate. Connections are made subsequent to the fabrication process.

The right-hand circuit takes care of the floating base case, in which a second diode 24 is connected in the emitter circuit of the transistor and a bias applied to a bias resistor 26 connected to diode 24.

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