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Browse Prior Art Database

Slow Power Supply

IP.com Disclosure Number: IPCOM000084015D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Higginbotham, AF: AUTHOR

Abstract

A slow power supply is incorporated into a battery operated dictation apparatus to eliminate objectionable audible speaker pops and clicks, and record head winding current transients.

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Slow Power Supply

A slow power supply is incorporated into a battery operated dictation apparatus to eliminate objectionable audible speaker pops and clicks, and record head winding current transients.

Operational amplifiers having outputs which are slew-rate limited, are used in a record current driver and power amplifier to drive faster bipolar driver circuits. Applying a step function of the voltage to the power inputs of these circuits causes objectionable transients at their outputs, due to the slow recovery rate of the operational amplifier outputs.

This slow supply circuit generates a supply voltage with a controlled rise time. By proper selection of transistor Q1, a minimum rise time can be guaranteed. This rise time is selected to insure that the operational amplifiers can follow the voltage ramp of the supply voltage. R1 is selected to guarantee saturation of Q1 for all load conditions after the rise.

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