IW873-00

iW873 Digital Green-Mode Synchronous Rectifier 1 Description The iW873 is a high performance synchronous rectifier controller with integrated MOSFET and driver for flyback converters operating at discontinuous conduction mode. It emulates the diode rectifier at the secondary side of the flyback to reduce conduction loss. The iW873 determines the timing of the driver by sensing the voltage across the RDS(ON) of the built-in MOSFET to achieve lossless sensing. Proprietary digital adaptive turn-off control technology is used to minimize the turn-off deadtime of the synchronous rectifier so that the parallel Schottky diode required by conventional synchronous rectifiers can be eliminated. The integrated driver has strong driving capability for high efficiency. The operating power consumption of the controller excluding the driver is less than 4mW at no load to achieve the ultra-low no-load power consumption for 5V applications. The iW873 integrates a pulse linear regulator to maintain the operation of the synchronous rectifier at low system output voltage when the system is operating in constant current (CC) mode. 2 Features ●● Integrated 60V power MOSFET ●● Wide VIN pin operating voltage up to 25V ●● Digital adaptive turn-off control minimizes dead-time and eliminates the parallel Schottky diode ●● Intelligent low power management achieves ultra-low no-load operating current ●● Lossless MOSFET VDS sensing for SR timing control ●● Integrated pulse linear regulator (PLR) allows SR operation at low system output voltage down to 2.4V in ●● 8-pin SOIC package typical 5V, 2A USB charger applications with iW873-00 3 Applications ●● Compact AC/DC adapters/chargers for media tablets and smart phones VOUT iW873 + 1 OUT VIN 8 2 DRAIN VCC 7 3 DRAIN GND 6 4 DRAIN GND 5 + RTN Figure 3.1 : iW873 Typical Application Circuit Product Summary www.dialog-semiconductor.com Rev. 1.0 1 of 6 2-June-2016 © 2016 Dialog Semiconductor iW873 Digital Green-Mode Synchronous Rectifier L VOUT + N iW873 U1 iW1602 RCDC 1 VCC 2 VSENSE 3 CFG OUTPUT 6 GND 5 CS/FS 4 1 OUT VIN 8 2 DRAIN VCC 7 3 DRAIN GND 6 4 DRAIN GND 5 + + RTN RFS RISNS Figure 3.2 : iW873-00 Typical Application Circuit (Using iW1602 as Primary-Side Controller) (Achieving