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AUTOBIASING AND DYNAMIC RANGE MAXIMIZATION IN A GREYSCALE DIFFERENTIAL AMPLIFIER

IP.com Disclosure Number: IPCOM000042669D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04

Publishing Venue

IBM

Related People

Authors:
Le, T [+details]

Abstract

The dynamic range of a differential greyscale video amplifier is maximized and autobiasing is achieved by the use of a simulation of the maximum voltage swing state to control the amplifier's current source. In Fig. 1, a signal proportional to the maximum state (Fig. 2) is needed to control current source transistor Q3. Such control is desirable in order to achieve autobiasing and to maximize the dynamic range of the amplifier. Since the amplifier is greyscale, only a portion of the current I0 is steered from side to side at any given time and the occurrence of the maximum state cannot be predicted. The outputs V01 and V02, therefore, cannot be monitored directly. Autobiasing and dynamic range maximization can still be achieved if a simulation is used.