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User's Guide
SNOA566A–October 2011–Revised April 2013
AN-2182 LM3466 Demonstration Board Reference Design
1 Introduction
The LM3466 integrates a linear LED driver for lighting systems that consist of multiple LED strings
powered by a constant current power supply. The LM3466 equalizes the current provided by the supply in
a pre-set ratio for each active LED string, where an active string is a fully turned on LED string, regardless
of the number of strings connected to the supply or the forward voltage of each LED string. If any LED
string opens during operation, the LM3466 automatically equalizes the supply current through all of the
remaining active LED strings. As a result, the overall brightness of the lighting system is maintained even
if some LED strings open during operation. The LM3466 consists of only linear circuitry so that the EMI of
the application circuit is not deteriorated.
This application report details the design of an LM3466 evaluation board that drives five LED strings, each
of which consists of 14 LEDs. The input current I
S
(of the constant current power supply) is 1.75A such
that the LED current is 0.35A per string. The evaluation board schematic, PCB layout, Bill of Materials,
and circuit design procedures are shown. Typical performance and operating waveforms are also provided
for reference.
2 Demonstration Board Schematic and PCB
Figure 1. LM3466 Evaluation Board PCB Top Overlay
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SNOA566A–October 2011–Revised April 2013 AN-2182 LM3466 Demonstration Board Reference Design
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