NCP4302

NCP4302 Secondary Side Synchronous Flyback Controller The NCP4302 is a full featured controller and driver that provide all the control and protection functions necessary for implementing a synchronous rectifier operation in a flyback converter. With the use of the NCP4302, the space conscious flyback applications such as Adaptors, chargers, set top boxes can achieve significant efficiency improvements at minimal extra cost. In addition to the synchronous rectifier control, the IC incorporates an accurate TL431 type shunt regulator, current monitoring circuit and optocoupler driver to provide a single IC secondary solution. The NCP4302 works with any type of flyback topology (continuous mode, Quasi-resonant mode or discontinuous mode) – providing a high level of versatility. Features http://onsemi.com MARKING DIAGRAM 8 8 1 SO-8 D SUFFIX CASE 751 1 x A L Y W G = Reference Voltage (A or B) = Assembly Location = Wafer Lot = Year = Work Week = Pb-Free Package 4302x ALYW G • Self-contained Control of Synchronous Rectifier in CCM, DCM, and • • • • • • • • • • • • • • QR Flyback Applications Interface to External Signal for CCM Mode True Secondary Zero Current Detection High Gate Drive Currents (2.5 A Source/Sink) High Voltage Operation Current Sense Flexibility (MOSFET RDS(on) OR CS Resistor) Accurate Low Voltage Reference - NCP4302A 2.55 V, 1% - NCP4302B 1.275 V, 1% Programmable Independent Secondary Side ton and toff Delays Maximum Frequency of Operation up to 250 kHz These are Pb-Free Devices Notebook Adapters LCD TV Adapters Consumer Appliances such as DVD, VCR Power Over Ethernet Applications (IP phones, Wireless Access Points) Battery Chargers PIN CONFIGURATION SYNC/CS 1 TRIG 2 CATH 3 VREF 4 (Top View) 8 VCC 7 DRV 6 GND 5 DLYADJ Typical Applications ORDERING INFORMATION Device NCP4302ADR2G Package SO-8 (Pb-Free) SO-8 (Pb-Free) Shipping† 2500/Tape & Reel NCP4302BDR2G 2500/Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. © Semiconductor Components Industries, LLC, 2008 1 February, 2008 - Rev. 2 Publication Order Number: NCP4302/D NCP4302 PIN DESCRIPTION Pin Number 1 Symbol SYNC/CS Description Connected to the flyback winding. The current on this pin is sensed and used to turn on the Synchronous Rectification MOSFET (SRFET). This pin is also used to sense the zero crossing of the MOSFET current either using the RDS(on) of the SRFET or using an external current sense resistor connected between drain of the SRFET and the flyback winding. Input pin for direct turn-off of the MOSFET. Typically connected to a signal from primary controller (for CCM mode) or a signal derived from the transformer (for QR mode). Has very short propagation delay to output (