Secondary Side Controller, Synchronous Rectification, for High Efficiency SMPS

The NCP4303A/B is a full featured controller and driver tailored to control synchronous rectifier circuitry in switch mode power supplies. Because of its versatility, it can be used in various topologies such as flyback, forward and half bridge resonant LLC. The combination of externally adjustable minimum on and off times helps to fight the ringing induced by the PCB layout and other parasitic elements. Therefore, a reliable and noise less operation of the SR system is insured. The extremely low turn off delay time, high sink current capability of the driver and automatic package parasitic inductance compensation system allow to maximize synchronous rectification MOSFET conduction time that enables further increase of SMPS efficiency. Finally, a wide operating VCC range combined with two versions of driver voltage clamp eases implementation of the SR system in 24 V output applications.

NCP4304 is recommended for new designs. NCP4303 will continue to be supported in production. NCP4304 was introduced to enhance the performance of LLC designs which use the Trigger input. Other performance and applications are the same.