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Multiple Current Source Circuit

IP.com Disclosure Number: IPCOM000073821D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Wiedmann, SK: AUTHOR

Abstract

An integrated circuit current source which is characterized by a reduced supply voltage and by excellent control of the output currents is shown. The circuit provides a fixed or variable current, proportional to the reference current I0, to each output load. The current I01, I02, I0N in the PNP transistors T0, T1, T2, TN, is kept constant by a feedback circuit employing transistors TB and TA. V5 may be tied together with the voltage supply +V2. The output currents are directly supplied from voltage supply +V2 without the requirement of a series resistor. This reduces the necessary supply voltage and thus the power dissipation. A small current gain or variation of current gain of the PNP transistors does not affect the control of the output currents.

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Multiple Current Source Circuit

An integrated circuit current source which is characterized by a reduced supply voltage and by excellent control of the output currents is shown. The circuit provides a fixed or variable current, proportional to the reference current I0, to each output load. The current I01, I02, I0N in the PNP transistors T0, T1, T2, TN, is kept constant by a feedback circuit employing transistors TB and TA. V5 may be tied together with the voltage supply +V2. The output currents are directly supplied from voltage supply +V2 without the requirement of a series resistor. This reduces the necessary supply voltage and thus the power dissipation. A small current gain or variation of current gain of the PNP transistors does not affect the control of the output currents. The reference current I0 can be varied by varying the voltage V4 or resistor R2.

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