iW671

Digital Green-Mode Synchronous Rectifier Controller

Rev. 1.2

Product Summary

© 2017 Dialog Semiconductor

www.dialog-semiconductor.com

1 of 7

28-March-2017

1 Description

The iW671 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 iW671 can emulate the diode

rectifier at the secondary side of the flyback to reduce conduction loss. The iW671 determines the timing of the driver

off 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 for 5V applications. The iW671 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.

The iW671 also integrates the adaptive voltage position monitor to detect the flyback converter output voltage

undershoot, enabling faster recovery from standby. Dialog’s iW1766C1 primary-side controllers are optimized to work

with the iW671 for very low output ripple, fast dynamic load response (DLR), and very low no-load power consumption

2 Features

● Digital adaptive turn-off control minimizes deadtime

and eliminates the parallel Schottky diode

● Integrated pulse linear regulator (PLR) allows SR

operation at low system output voltage down to 2V in

typical 5V, 2.5A USB charger applications

● Wide input operating voltage up to 30V

● Optimized 5V MOSFET gate driver

3 Applications

● Compact AC/DC adapters/chargers for media tablets

and smart phones

Figure 3.1 : iW671 Typical Application Circuit

● Intelligent low power management achieves ultra-low

no-load operating current < 0.65mA

● Integrated adaptive voltage position monitor for fast

flyback output voltage undershoot detection

● 8-pin SOIC and 8-pin MSOP packages

RTN

VPS

DRV

1

2

3

8

7

6

4

5

PLRIN

DRAIN

+

+

GND

OUT

iW671