AN2983 Datasheet, PDF (1/32 Pages) STMicroelectronics – Constant current inverse buck LED driver using L6562A

AN2983
Application note
Constant current inverse buck LED driver using L6562A
Introduction
Whenever a lighting application, such as street lighting for example, requires an elevated
number of LEDs, there are basically two solutions: the first is to connect all the diodes in
series in a single "string"; the second is to place several strings in parallel with fewer
elements in each one.
The first solution, even if simpler, poses stringent safety requirements due to the high supply
voltage. The latter needs a lower input voltage but the current through each string has to be
independently controlled.
Since, from a system point of view, the second solution seems more viable, we have
developed an application to investigate the possibility of employing an L6562A to implement
such a constant current controller. This document describes the EVL6562A-LED
demonstration board and summarizes the relevant results obtained.
Figure 1. EVL6562A-LED: L6562A constant current inverse buck driver module
December 2009
Doc ID 15679 Rev 1
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