IW673-20

The iW673 is a high performance synchronous rectifier controller with an integrated MOSFET driver for flyback converters operating at discontinuous conduction mode. Combined with the MOSFET, the iW673 can emulate the diode rectifier at the secondary side of the flyback to reduce conduction loss. The iW673 determines the timing of the driver by sensing the voltage across the RDS(ON) to achieve lossless sensing. The iW673 uses proprietary digital adaptive turnoff control technology to minimize the turn-off deadtime of the synchronous rectifier so that the parallel Schottky diode required by conventional synchronous rectifiers can be eliminated. The integrated driver has strong driving capability for high efficiency. The operating power consumption of the controller excluding the driver is less than 4mW at no load to achieve the ultra-low no-load power consumption at 5V output. The iW673 integrates a pulse linear regulator to maintain the operation of the synchronous rectifier at low system output voltage when the system is operating in constant current (CC) mode.