Electronic Design

Soft-Recovery Diode Boosts Power-Factor Correction

A series of hyperfast soft-recovery diodes has been released by International Rectifier. These devices have been specifically designed to improve performance and power density in power-factor correction (PFC) boost circuits used in offline switch-mode power supplies. When matched with optimized HEXFET power MOSFETs, these application-specific diodes can cut power losses by almost 32% in PFC circuits, according to IR.

Initial family members include 8-, 15-, and 30-A diodes with a 600-V blocking voltage. To reduce conduction and switching losses, these rectifiers offer low forward-voltage drop and reverse leakage current. For instance, the 8-A diode's maximum forward-voltage drop is 2.1 V, while its reverse leakage current at room temperature is 100 µA.

These diodes have a hyperfast recovery time, providing soft-switching characteristics and a spike-free reverse-recovery waveshape. This time is as low as 30 ns for the 8-A unit, and it goes to 40 ns for the 30-A version. The diodes additionally can handle a maximum junction temperature of 175ºC, offering a large safe-operating area.

Suitable for power levels up to 1.5 kW, the PFC-specific diodes come in TO-220, TO-262, TO-247, and D2PAK packages. Sampling now, production begins next month. In 100,000-piece quantities, pricing starts at $0.55.

International Rectifier, 233 Kansas St., El Segundo, CA 90245; (310) 252-7105; www.irf.com.

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