Synchronous Rectification Drivers Tout Power Efficiency
Fri, 05/21/2010 - 7:32am
ON Semiconductor’s NCP4303A and NCP4303B synchronous rectification controller and driver integrated circuits (ICs) are targeted at use in switch mode power supplies (SMPS) for applications such as ATX power supplies, flat screen televisions, high power AC-DC adapters, and gaming consoles. Capable of a maximum operating frequency of 500 kHz, these ICs feature high current gate drivers along with high-speed logic circuitry to provide appropriately timed drive signals to the synchronous rectification MOSFET. The low turn-off delay time of 4ns typical, combined with the high sink current capability of the drivers and the automatic package parasitic inductance compensation system allow synchronous rectification MOSFET conduction time to be maximized - thus increasing the efficiency of the SMPS. Externally adjustable minimum on and off times (which are independent of the Vcc level) help to deal with the ringing induced by PCB layouts and other parasitic elements. The NCP4303 also features a trigger input that can be used to interface with the primary side of the power supply, allowing use in constant current applications.