IR extends Smartrectifier IC range

The 200V dual-smart secondary-side rectifier driver IC is designed to drive two N-Channel power Mosfets used as synchronous rectifiers (SR) in resonant half-bridge topologies.

In contrast with traditional current transformer SR methods, the IR1168 accurately 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 to simplify design.

While synchronous rectification provides significant energy savings compared with diode-based designs, traditional SR methods are complex and require a high component count.

Using only two gate resistors and a supply capacitor, the IR1168 delivers a lower system temperature and increased power density, for even greater efficiency and reliability than existing SR methods, while simplifying design and reducing component count to shrink PCB size.

Co-designed with IR's Directfet Mosfets, which feature IR's Trench silicon and packaging technology, the IR1168-based system delivers an efficiency improvement of 1.5 per cent for a standard 240W LCD TV SMPS and a reduction of rectifier device temperature of 25C, while shrinking board size by two thirds.

The IR1168, featuring IR's high-voltage IC technology, supports burst mode operation to deliver efficiency benefits even at light loads.

Ruggedness and noise immunity are accomplished using an advanced blanking scheme and double-pulse suppression that allows reliable operation in fixed- and variable-frequency applications.

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