40W AC-DC LED driver solution based on iW3620 - power supply circuit - circuit diagram

iW3620 is a high-performance AC/DC offline LED driver. The device operates in quasi-resonant mode under high load conditions to obtain high efficiency and various built-in protection features to reduce EMI. The operating frequency is up to 130kHz, and the universal input voltage is 85 Vac to 264 Vac, can drive 40W LED lighting. This article introduces the main features and typical application circuits of iW3620.

iW3620: Digital PWM Constant Current Controller for AC/DC LED Driver

The iW3620 is a high performance AC/DC offline LED driver which uses digital control technology to build peak current mode PWM flyback power supplies. The device operates in quasi-resonant mode at heavy load 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 iW3620 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 current limit function enables optimized transformer design in universal off-line applications over a wide input voltage range.

iW3620 main features:

Primary-side feedback eliminates opto-isolators and simplifies design

Quasi-resonant operation for highest overall efficiency and low EMI

Up to 130 kHz switching frequency enables small size

Very tight LED constant current regulation

Built-in output constant-current control with primary-side feedback for LED driver.

Low start-up current (10 μA typical)

Built-in soft start

Built-in short circuit protection and output overvoltage protection

Current sense resistor short protection

Over-temperature Protection

Open circuit protection

Universal input range from 85 Vac to 264 Vac

Single-fault protection

Small input bulk capacitor

Long MTBF

High efficiency

iW3620 Application:

Solid State LED lighting for incandescent, halogen, and fluorescent tube replacementFigure


1 Typical application circuit of iW3620