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Single Stage TSR With Regulations in Main Switching Transistor and Output Filter Circuits

IP.com Disclosure Number: IPCOM000086906D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Johari, GC: AUTHOR

Abstract

This circuit provides pulse-width modulation control of the main switching transistor and, in addition, stores energy in the transformer to provide a separately controlled energy contribution to the output. Thus, the circuit provides control during both the ON and OFF times of the main switch. This provides quick response to change in load and also allows individual fine regulation where multiple output circuits are desired.

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Single Stage TSR With Regulations in Main Switching Transistor and Output Filter Circuits

This circuit provides pulse-width modulation control of the main switching transistor and, in addition, stores energy in the transformer to provide a separately controlled energy contribution to the output. Thus, the circuit provides control during both the ON and OFF times of the main switch. This provides quick response to change in load and also allows individual fine regulation where multiple output circuits are desired.

In Fig. 1, pulse-width modulation control 10 operates switch S1 in an on-off cycle which compensates for variations in Ein. Primary winding 12 thus receives a square wave input. During the ON period of S1, energy is transferred from input through transformer action in T to both the output and C1. Part 14 of T secondary 16 is used to charge capacitor C1. During the OFF period of S1, energy is supplied to capacitor C2 through diode 18 and line 24 due to flyback action.

It is assumed that the transformer design incorporates appropriate magnetizing inductance to transfer enough flyback energy for regulation of the output voltage. Through a feedback control mechanism 20, switch 52 is operated at a fixed frequency and its pulse width is varied such that it continually adjusts the voltage of capacitor C1 required to produce a constant output voltage. When S2 is ON, flyback energy through diode 18 and from C2 is communicated through line 22 to point "A" When S2...