Synchronous rectifier controller With Ultra Low Standby current

The UCC24630 SR controller is a

high-performance controller and driver for N-channel MOSFET power devices used for

secondary-side synchronous rectification.

The combination of controller and

MOSFET emulates a near-ideal diode rectifier. This solution not only directly

reduces power dissipation of the rectifier but also reduces primary-side losses as

well, due to compounding of efficiency gains.

Utilizing a volt-second balancing

control method, the UCC24630 is designed for flyback power supplies over a

wide-output voltage range since the device is not connected directly to the MOSFET

drain. The SR drive turn-off threshold is not dependent on the MOSFET

RDS(on) which allows optimizing for maximum conduction time. Also

secondary current ringing due to device and layout inductance does not affect the SR

turn-off threshold.

The UCC24630 controller offers a

programmable false-trigger filter, a frequency detector to automatically switch to

standby mode during low power conditions and pin fault protections. The UCC24630 is

compatible with DCM, TM and CCM operation.

The wide VDD operating range, wide

programming range of the VPC voltage and blanking time, allows use in a variety of

flyback converter designs.