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Power Line Disturbance Protected Power Supply

IP.com Disclosure Number: IPCOM000084007D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Freund, CW: AUTHOR [+3]

Abstract

Continuous power dissipation in the regulator circuit of a series regulated power supply is reduced without sacrificing power line disturbance performance. The regulating circuit automatically responds to reduced voltage caused by a power disturbance and switches to a higher voltage DC source to maintain regulation. After the disturbance has ceased, the regulator reverts back to the lower voltage DC source to avoid high-power dissipation by the regulating circuit.

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Power Line Disturbance Protected Power Supply

Continuous power dissipation in the regulator circuit of a series regulated power supply is reduced without sacrificing power line disturbance performance. The regulating circuit automatically responds to reduced voltage caused by a power disturbance and switches to a higher voltage DC source to maintain regulation. After the disturbance has ceased, the regulator reverts back to the lower voltage DC source to avoid high-power dissipation by the regulating circuit.

In the figure, AC line voltage is applied to winding 11 of transformer T1. Diodes D3 and D4 are connected to center-tapped secondary winding 12 to provide a first DC voltage V1 which is filtered by capacitor C2. Diodes D1 and D2 are connected to center-tapped secondary winding 13 to provide a second DC voltage, filtered by capacitor C1 that is lower than V1. This lower voltage is connected to the collectors of NPN transistor Q1 and PNP transistor Q3.

Reference voltage V3, equal to the desired regulated output voltage V2 is applied to the noninverting input of amplifier A1, and V2 is applied to the inverting input of A1. The collector of NPN transistor Q2 is connected through resistor R1 to V1 and the emitter of Q2 is connected to drive the base of Q1. The output of A1 drives the base of Q2.

Under normal line voltage conditions V2 is derived from winding 13 through transistor Q1. As V2 drops the output of amplifier A1 becomes more positive, causing Q2 to cond...