1 Description

The iW673 is a high performance synchronous rectifier controller with an integrated MOSFET driver for flyback

converters operating at discontinuous conduction mode. Combined with the MOSFET, the iW673 can emulate the diode

rectifier at the secondary side of the flyback to reduce conduction loss. The iW673 determines the timing of the driver

by sensing the voltage across the RDS(ON) to achieve lossless sensing. The iW673 uses proprietary digital adaptive turnoff

control technology 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 at 5V output. The iW673 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

● Digital adaptive turn-off control minimizes dead-time

and eliminates the parallel Schottky diode

● Integrated pulse linear regulator (PLR) enables SR

operation at down to 2.4V system output when system

is in constant current (CC) mode with iW673-00,

iW673-01, or iW673-20

● Wide VIN pin operating voltage up to 25V (16V for iW673-00)

● Optimized 5V MOSFET gate driver Intelligent low power

management achieves ultra-low

no-load operating current

● Lossless MOSFET VDS sensing for SR timing control

● 6-pin SOT23 package