1 Description
The iW3671 is a single-stage high-performance AC/DC primary-side-regulation PWM controller with power factor
correction (PFC). It is designed to support flyback and buck-boost topologies at output power levels up to 100W.
The iW3671 supports different types of loading including constant power (CP) loads such as a second-stage DC/DC
converter; and constant resistance (CR) loads such as LED light strips.
The iW3671 uses Dialog’s PrimAccurate™ technology to provide accurate constant voltage (CV) and constant
current (CC) regulation across AC line and load conditions. The digital control eliminates the need for external
loop compensation while maintaining stability across all operating conditions. With Dialog’s patented PF-Boost
TM
technology, the iW3671 can achieve power factor (PF) greater than 0.9 and total harmonic distortion (THD) less than
20% at 50% or greater loading and across the entire AC line voltage range.
The iW3671 can achieve less than 150mW standby power loss while keeping excellent load transient response in CV
mode. In addition, there is no audible noise during load transient or during startup, which is a typical shortcoming of
most PFC CV controllers. Startup time is less than 0.25s with active startup circuit and advanced startup control in the iW3671.
The iW3671 also features various protections such as output over-voltage, output short-circuit, AC over-voltage, AC under-voltage, current-sense-resistor short, over-current and over-temperature protections. This ensures great system reliability.

2 Features
● Universal AC input voltage range 90VAC ~ 305VAC
● Supports up to 100W output power in tiny SOT-23 package
● CV mode AC line and load regulation < ±3%
● CC mode AC line and load regulation < ±5%
● PF > 0.9 and THD < 20% across AC line voltage for
> 50% of full load
● Fast startup time < 0.25s
● Standby power < 150mW at 230VAC input up to 100W
with external active startup DFET circuit
● No audible noise across AC line and load conditions,
and during load transient or startup
● Wide operating supply voltage (VVCC) range from 8.0V to 20V
● Comprehensive protection features
x Output over-voltage protection
x Output short-circuit protection
x AC over-voltage protection
x AC under-voltage protection (Brown-out)
x Cycle-by-cycle peak current limit
x Current-sense-resistor short protection
x Over-temperature protection