EL SEGUNDO, CA, January 24, 2000 - International Rectifier (IR^®), the power conversion experts, now offers the IR1175 Synchronous Rectification IC (SRIC), a single-chip, application-specific IC designed to provide optimized gate drive for the MOSFETs configured as synchronous rectifiers in the secondary side of an isolated DC-DC converter. The first of its kind, this IC programs the gate drives to insure that the losses through the synchronous rectifiers are minimized and the parasitic diodes do not conduct. When used with IR application-specific HEXFET^® power MOSFETs, the IR1175 SRIC boosts DC-DC converter efficiency to 90 percent at 3.3V output.

In operation, the IR1175 uses a modified phase lock loop (PLL) to lock the switching frequency of the secondary-side synchronous rectification MOSFETs to the primary-side switching action. This allows the secondary-side MOSFETs to be pre-fired with full programmable control of turn-on transition lead time, as well as the dead time and overlap between gate drive signals. Pre-firing the MOSFETs eliminates parasitic diode conduction and all the output current is now conducted through the active channels of the MOSFETs with lower losses. The operation of the IR1175 SRIC is independent of the primary-side topology and it can be used in both forward and active clamp converters.

IR1175 Datasheet

"Our new IR1175 SRIC is the easiest and most practical way to implement more efficient synchronous rectification," said David Tam, Vice President of the Power IC Group at IR. "Using the new device with IR application-specific MOSFETs allows designers of even the simplest forward converter to match the efficiency of patented active clamp topologies with their expensive licensing fees." "In other words, the IR1175 provides the designer with a simple and speedy path to more efficient and lower cost DC-DC converters," he continues, "particularly those providing lower output voltages less than 3.3 volts."

Development of commercial DC-DC converters using the IR1175 is underway at leading manufacturers of telecom power converters. IR is also developing new ICs to expand the applicability of the secondary-side predictive switching concept to other switching topologies and a wider range of output voltage and power levels. Samples of the IR1175 Synchronous Rectification IC are available from IR on the Internet at a special DC-DC conversion Web site at http://dc2dc.irf.com, as well as through IR distributors and the customer service line. Volume production is scheduled for March, 2000.