An active power factor controller (PFC) integrated circuit, normally used in AC circuits, has been used for DC-to-DC boost conversion with a stable output voltage for a variable DC input voltage as obtained from photovoltaic (PV) sources. The circuit described here uses a power factor controller MC 34262 to give approximately 400 V-DC output for an input variation from 90 to 280 V-DC. The maximum efficiency achieved was 98% at 450 W. Comparisons between AC and DC operations have been made. (C) 2007 Elsevier Ltd. All rights reserved.