White LED driver constant current isolated offline circuit diagram

High brightness white  LEDs are becoming a prominent source of light and often have better efficiency and reliability when compared to that of conventional light sources. While LEDs can operate from an energy source as simple as a battery and resistor, most applications require an efficient energy source not only for the reduction of losses, but also for the lumen maintenance of the LED itself. Using integrated off line switching regulators like the VIPer12A and VIPer22A in a constant current configuration, a low cost, high efficient LED driver for multiple LEDs has been developed. This document introduces the isolated and non-isolated offline constant current LED driver based on the VIPerX2A family.

All three LED driver configurations operate in the extended wide range input voltage, from 90 to 264V ac.

VIPer12A current selectable LED driver circuit diagram

The circuit diagram is designed to display the full functionality of VIPer12A and VIPer22A as white LED drivers to drive 1W, 3W as well as 5W LEDs at wide range input voltage. The components selected are optimized for 5W LED driver application. The following pages contain the schematics and bills of materials that reflect the components used on the boards. Based on this circuit, there are six different configurations with different output power level that could be derived by making minor components changes to the evaluation board. The subsequent pages will show the schematics and bills of materials for the circuit to drive 1W, 3W and 5W.

 LEDs.

Download: VIPower: Offline constant current LED driver using VIPer12/22A http://www.st.com/web/en/resource/technical/document/application_note/CD00012203.pdf