International Rectifier, IR®, introduces new 500V L-Series HEXFET® power MOSFETs with fast recovery body diode for reliable operation of zero-voltage switching (ZVS) power supplies, especially at light loads. The new devices expand the IR line of MOSFETs for ZVS power supplies commonly found in telecom and other high-end switch mode power supplies. Overcoming device failure is of the utmost importance in an industry where 100% service up-time is expected and where wide load excursions are very common. The new L-Series MOSFETs eliminate the need for series Schottky and anti-parallel high voltage diodes used in conventional designs, thereby reducing part count, simplifying PCB layouts, reducing overall losses and improving power density. Zero-voltage switching is emerging as the power supply design of choice for high current power supplies. Power supplies using ZVS circuits operate efficiently at high frequencies, reducing passive component size and increasing power density. When MOSFETs are used in ZVS circuits operating at frequencies up to 250kHz, body diode reverse recovery characteristics become critical, especially under light load conditions when the MOSFET on-time is very short. MOSFETs can only withstand voltage across its drain and source after the integral body diode has completed the reverse recovery period. The reverse recovery time of the integral body diode has a direct impact on the minimum duty cycle. The L-Series MOSFETs, targeted for ZVS applications, have greatly improved body diode characteristics: close to 70% reduction in reverse recovery time (Trr max), as low as 250ns, the best in the industry. In addition, the new devices demonstrate over 70% reduction in diode reverse recovery charge (Qrr) reducing switching losses, and over three times better diode peak recovery (dV/dt) immunity compared to standard devices. Bhasy Nair, Marketing Manager for AC-DC products at International Rectifier, said, "Most MOSFETs available in the market place are optimized for hard-switched circuits and can fail in ZVS circuits under certain operating conditions. The body diode characteristics make the new L-Series MOSFETs the best choice for ZVS applications on the market." The turn on losses are virtually eliminated in the ZVS architecture power supply designs by turning-on the MOSFETs when its integral body diode is conducting. By significantly reducing switching losses and the overall losses in the power-switching device, the SMPS can be designed to operate at higher frequencies to reduce the size of passive components, such as transformers and capacitors, thereby increasing its power density. ZVS is becoming more popular as the industry seeks higher efficiency and higher power outputs in the same or smaller footprint. The new HEXFET MOSFETs for ZVS applications are available immediately. Pricing begins at US $1.65 each for the IRFB17N50L in 10,000-unit quantities.

Press Release