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# Temperature Stable Constant Voltage Source

IP.com Disclosure Number: IPCOM000095255D
Original Publication Date: 1965-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 24K

IBM

## Related People

Hart, RL: AUTHOR [+1]

## Abstract

This circuit provides a constant voltage source which is substantially independent of variations in temperature over a wide range. A voltage divider R(1)R(2) has its intermediate junction coupled to an output terminal Z by way of a pair of emitter-followers T(1) and T(2) of opposite conductivity types. R(1) is at least ten times larger than R(2) so that I(1) is dependent upon R(1). Also, I(1) is at least ten times larger than I(B) to minimize effects due to changes in I(B). V(O) = V(B) + V(BE(T1)) - V(BE(T2)). The transistors are matched so that the base-emitter voltage drops cancel each other. If I(B) is compensated for temperature variations, V(O) remains stable. V(O) is maintained constant for any load current as long as T(2) is operated Class A.

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Temperature Stable Constant Voltage Source

This circuit provides a constant voltage source which is substantially independent of variations in temperature over a wide range. A voltage divider R(1)R(2) has its intermediate junction coupled to an output terminal Z by way of a pair of emitter-followers T(1) and T(2) of opposite conductivity types. R(1) is at least ten times larger than R(2) so that I(1) is dependent upon R(1). Also, I(1) is at least ten times larger than I(B) to minimize effects due to changes in I(B). V(O) = V(B) + V(BE(T1)) - V(BE(T2)). The transistors are matched so that the base- emitter voltage drops cancel each other. If I(B) is compensated for temperature variations, V(O) remains stable. V(O) is maintained constant for any load current as long as T(2) is operated Class A.

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