March 2007

Rev 4

1/30

AN2042

Application note

VIPower: dimmable driver for high

brightness LEDs with VIPer22A-E

Introduction

This application note introduces an innovative solution to drive high brightness 1W LEDs

(Light Emitting Diode), using VIPer22A-E in flyback configuration with output current control.

The power supply is able to drive an array of 1 to 8 LEDs in European range, i.e. 185-265

VAC with no modifications. By means of an input voltage doubler, it is possible to use the

same VIPer device also in U.S. input voltage range, guaranteeing the specs. A new control

technique is used to adjust the duty cycle of the output current, in order to dim the luminosity

of the LEDs down to 10% of the maximum value (patent pending by STMicroelectronics).

The proposed driver can be suitably used in applications such as landscape lighting, street

lighting, car parks, bollards, garden lighting, large area displays and so on.

Also domestic applications such as room lighting, decorative fixtures and architectural

lighting can benefit from the advantage of this dimmable light source.

10W Dimmable LEDs driver board layout

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