iW1707

Low-Power Off-Line Digital Green-Mode PWM Controller

Rev. 1.1

Datasheet

© 2022 Renesas Electronics

www.renesas.com

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24-Jan-2022

1 Description

The iW1707 is a high performance AC/DC power supply controller which uses digital control technology to build

peak current mode PWM flyback power supplies. The device directly drives a power BJT and operates in quasi-

resonant mode to provide high efficiency along with a number of key built-in protection features while minimizing the

external component count, simplifying EMI design and lowering the total bill of material cost. The iW1707 features a

distinctive soft-start scheme, which allows for fast and yet smooth start-up with both small and large capacitive loads.

The iW1707 removes the need for secondary feedback circuitry while achieving excellent line and load regulation. It

also eliminates the need for loop compensation components while maintaining stability over all operating conditions.

Pulse-by-pulse waveform analysis allows for a loop response that is much faster than traditional solutions, resulting in

improved dynamic load response. The built-in power limit function enables optimized transformer design in universal

off-line applications and allows for a wide input voltage range.

Dialog’s innovative propietary technology ensures that power supplies built with the iW1707 can achieve both highest

average efficiency and less than 100mW no-load consumption, and have fast yet smooth start-up with a wide range

of capacitive loads with output voltage up to 12V, and are ideal for network and home appliance power supplies

applications.

2 Features

● Primary-side feedback eliminates optoisolators and

simplifies design

● Adaptively controlled soft start enables fast and

smooth start-up for a wide range of capacitive loads

(from 330μF to 6,000μF)

● Active start-up scheme enables shortest possible

turn-on delay

● Direct drive of low-cost BJT switch

● Very tight constant voltage regulation

● Intrinsically low common mode noise

● Optimized 72kHz maximum PWM switching frequency

achieves best size and efficiency

3 Applications

● Network power adapters for ADSL, wireless access

points, routers

● AC/DC power supplies in home appliances

● Adaptive multi-mode PWM/PFM control improves

efficiency

● Quasi-resonant operation for highest overall

efficiency

● Dynamic base current control

● No external compensation components required

● Complies with EPA 2.0 energy-efficiency

specifications with ample margin

● Built-in short circuit protection and output overvoltage

protection

● Built-in current sense resistor short circuit protection

● Constant current control enables output current limit

and overload protection

● No audible noise over entire operating range