Energy-efficient synchronous rectification drivers now available

ON Semiconductor has expanded its portfolio of products to support next generation power system design. The NCP4303A and NCP4303B are full featured synchronous rectification controller and driver integrated circuits (ICs) 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. Their unique features provide an efficient and flexible solution for secondary side rectification in SMPS.

Capable of a maximum operating frequency of 500 kHz, these new ICs feature high current gate drivers along with high-speed logic circuitry to provide appropriately timed drive signals to the synchronous rectification MOSFET. The extremely low turn-off delay time of 40 ns 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. This results in reliable, noiseless operation. 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.

The NCP4303 is available with two different gate drive clamp voltages to tailor to the characteristics of different synchronous MOSFETs available on the market. The NCP4303A has a gate drive clamp of 12 V, while the NCP4303B has a 6-V gate drive clamp. These versatile devices can be used in various power topologies, such as flyback, forward, and half bridge resonant LLC.

For more information, contact ON Semiconductor, 5005 East McDowell Rd., Phoenix, AZ 85008. Phone: (888) 743-7826.