User manual

V
IN
(V)
EFFICIENCY (%)
100
95
90
85
80
75
70
0 16 32 48 64 80
User's Guide
SNVA403C–July 2009–Revised May 2013
AN-1985 LM3429 Buck-Boost Evaluation Board
1 Introduction
This wide range evaluation board showcases the LM3429 NFET controller used with a buck-boost current
regulator. It is designed to drive 4 to 8 LEDs at a maximum average LED current of 1A from a DC input
voltage of 10 to 70V.
The evaluation board showcases most features of the LM3429 including PWM dimming, overvoltage
protection and input under-voltage lockout. It also has a right angle connector (J7) which can mate with an
external LED load board allowing for the LEDs to be mounted close to the driver. Alternatively, the LED+
and LED- banana jacks can be used to connect the LED load.
The buck-boost circuit can be easily redesigned for different specifications by changing only a few
components (see Alternate Designs). Note that design modifications can change the system efficiency for
better or worse. See the LM3429 LM3429Q1 N-Channel Controller for Constant Current LED Drivers
(SNVS616) data sheet for a comprehensive explanation of the device and application information.
Figure 1. Efficiency with 6 Series LEDS AT 1A
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SNVA403C–July 2009–Revised May 2013 AN-1985 LM3429 Buck-Boost Evaluation Board
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