Browse Prior Art Database

DC - DC Converter

IP.com Disclosure Number: IPCOM000077015D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Marple, WP: AUTHOR

Abstract

DC-DC-transformer coupled converter 10 employs a stacked split-capacitor bridge C1-C4 on the primary side of transformer T1, thereby allowing the use of lower voltage rating switching transistors Q1-Q4.

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DC - DC Converter

DC-DC-transformer coupled converter 10 employs a stacked split-capacitor bridge C1-C4 on the primary side of transformer T1, thereby allowing the use of lower voltage rating switching transistors Q1-Q4.

In operation, the input DC voltage Vin divides equally among capacitors C1- C4. Transistors Q1-Q4 are operated in a push-pull pairs, i.e. the pair Q1 and Q3 and the pair Q2 and Q4. When a particular pair is turned on, the respective voltages of the capacitors associated with the transistors of the particular pair appear across the primary windings 11 and 12 of transformer T1. For example, the voltages across capacitors C1 and C3 appear across the primary windings 11 and 12, respectively, when transistors Q1 and Q3, respectively, are turned on. As a result, a voltage is induced in the secondary winding 13 which is proportional to the capacitive voltages and the turns ratio of the transformer T1. Likewise, a current in the secondary winding is provided which is proportional to the sum of the two primary currents and the turns ratio of the transformer. In this manner, transistors Q1-Q4 are effectively operated in parallel to supply an output load current of significant magnitude even though the transistors Q1-Q4 are operated in series at their lower breakdown voltage requirements. By judiciously selecting the parameters of the control signals A and B, the converter 10 may be operated full-time i.e. 100% duty cycle, or may be pulse-width modulated an...