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Sequential Transistor Switch Power Supply

IP.com Disclosure Number: IPCOM000073669D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Trubell, LP: AUTHOR

Abstract

The sequential transistor switch is basically a DC-DC regulator scheme which allows regulated voltages to be obtained directly from the rectified line voltage.

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Sequential Transistor Switch Power Supply

The sequential transistor switch is basically a DC-DC regulator scheme which allows regulated voltages to be obtained directly from the rectified line voltage.

The STS DC-DC regulator shown in Drawing A consists of three basic elements - the unit DC-DC converter 1-6, the output LC filter, and the feedback network FB. By interconnecting the rectified secondaries of each unit DC-DC converter into a ring then firing each one sequentially (with or without overlap firing), a series of output pulses are produced. The LC filter then averages and filters the pulses to form a low ripple output voltage.

The unit DC-DC converter of Drawing B consists basically of a high voltage switching device and a high frequency transformer. Its main purpose is to supply a transformer isolated output pulse of a fixed duration without saturating the transformer. During its off time, current through the reset winding resets the transformer flux operating point to its original value.

Regulation of the output voltage is accomplished by the amount of overlap firing of each unit DC-DC converter connected as shown in Drawing C. Overlap firing causes two secondary windings to be connected in series for the duration of the overlap. As such, the regulation scheme consists of a pulse width or time ratio control method resulting from overlap firing.

The advantages of this method, over that of conventional pulse width control are: 1) the pulse width variation...