Browse Prior Art Database

FET Current Driver Having Large Dynamic Range

IP.com Disclosure Number: IPCOM000050805D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Concannon, MP: AUTHOR [+2]

Abstract

This field-effect transistor circuit uses enhancement and depletion devices to provide a voltage-responsive current sink capable of providing a current between 0 and 0.8 milliamp in response to an input voltage change of 0.5 volt.

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FET Current Driver Having Large Dynamic Range

This field-effect transistor circuit uses enhancement and depletion devices to provide a voltage-responsive current sink capable of providing a current between 0 and 0.8 milliamp in response to an input voltage change of 0.5 volt.

Depletion devices T1 and T2 act as a voltage divider to provide an input- responsive optimized operating voltage for the gate of inverting amplifier enhancement device T4, having depletion device T3 as its load. Overall amplifier gain is increased by providing positive feedback from the drain of T4 to the gate of T2. The variable voltage at the drain of T4 is converted to a variable current Iout by depletion device T5 in series with output load RL.

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