A 250 W High Density Point - of - Load Converter

This thesis describes the design and construction of a 250 W, 35-60 Vin, 5 Vout dc-dc power converter with a switching frequency of 500 kHz. The converter uses square wave switching and is composed of two power processing stages in series. The first stage, a boost converter, regulates the output voltage of the converter. The second stage, a push-pull converter operating at 100% duty-cycle, provides isolation and steps the bus voltage created by the first stage down to the load voltage. The converter was fabricated using a copper thick film process with commercially available surface mount components. This fabrication method minimizes parasitic inductances and allows the designer to reduce the coupling of the noise generated in the power section into the control section. The converter had an efficiency of 82% at full power and achieved an unpackaged power density of 80 Wfin3• During a 15 A transient in the output current, the peak error in the output voltage was 3% and the output voltage was within 1.5% of the regulated voltage after 10 j.Ls. Thesis Supervisor: Professor Martin F. Schlecht Title: Associate Professor of Electrical Engineering and Computer Science