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Browse Prior Art Database

Monolithic Current Source

IP.com Disclosure Number: IPCOM000074581D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Mitchell, JW: AUTHOR

Abstract

The matching of base-emitter voltage drops in the transistors of this circuit allows tight control over the current Ic flowing through a number of loads Zx.

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Monolithic Current Source

The matching of base-emitter voltage drops in the transistors of this circuit allows tight control over the current Ic flowing through a number of loads Zx.

The differential amplifier comprising transistors T1, T2, T3 and T4 and a feedback connection by transistor T5 between the base of transistor T4 and the collector of transistor T1 compares the voltage VREF to the voltage Vg. If there is any difference in potential between these two voltages, the voltage Vg is made equal to the voltage VREF by the feedback connection changing the base current Ib to the transistor T5 so that the current Ic is maintained equal to VREF/R1. If this circuit is formed on a single monolithic chip, all the currents Ic will be equal as a result of beta tracking of transistors T5, T6, T7 and T8.

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