Rectifier IC

International Rectifier has expanded its family of SmartRectifier ICs with the introduction of the IR1168 for AC-DC power converters for high-end LCD TVs.

The 200 V dual smart secondary-side rectifier driver IC is designed to drive two n-channel power MOSFETs used as synchronous rectifiers in resonant half-bridge topologies.

In contrast to traditional current transformer SR methods, the device determines turn-on and turn-off based on MOSFET drain sensing voltage in close proximity to zero current transition, eliminating the need for additional components.

Using two gate resistors and a supply capacitor, the IC delivers a lower system temperature and increased power density.

Co-designed with the company’s DirectFET MOSFETs, which feature IR’s latest trench silicon and packaging, the device delivers an efficiency improvement of 1.5% for a standard 240 W LCD TV SMPS and a reduction of rectifier device temperature of 25 °C while shrinking board size by two-thirds.

It supports burst mode operation for better efficiency even at light loads. Ruggedness and noise immunity are accomplished using a blanking scheme and double-pulse suppression that allows operation in fixed and variable frequency applications.

Other key features include maximum 500 kHz switching frequency, anti-bounce logic and UVLO protection, 4 A peak turn-off gate drive current, microprocessor start-up and ultra low quiescent current, 10.7 V gate drive clamp, 70 ns turn-off propagation delay and a wide V_CC operating range from 8.6 to 18 V.