LM3409HVEVAL: 1.5A @ 42V Max, 48V in

Summary

This evaluation board showcases the LM3409HV PFET controller for a buck current regulator. It is designed to drive 12 LEDs (VO = 42V) at a maximum average LED current (ILED = 1.5A) from a DC input voltage (VIN = 48V). The switching frequency (fSW = 400 kHz) is targeted for the nominal operating point, however fSW varies across the entire operating range. The circuit can accept an input voltage of 6V-75V. However, if the input voltage drops below the regulated LED string voltage, the converter goes into dropout and VO = VIN ideally.

Since the board contains a buck regulator designed for 48V input, the efficiency is very high at input voltages near or less than 48V. The switching frequency increases as input voltage increases, yielding lower efficiency at higher input voltages. Note that increasing the off-time resistor (R6) will increase the efficiency at high input voltage.

Specifications

Manufacturer	Texas Instruments
Category	Lighting
Sub-Category	LED Drivers - DC In
Eval Board Part Number	LM3409HVEVAL/NOPB-ND
Eval Board Supplier	Texas Instruments
Eval Board	Normally In Stock
Voltage In	42 ~ 75 V (48 V)
Topology	Step Down
Current Out	1.5 A
Voltage Out (Max)	42 V
Outputs and Type	1 Non-Isolated
Efficiency @ Conditions	>95%, 48V in, 12 LEDs(42V) @ 1.5 A
Features	Dimming Control Shutdown, Enable, Standby Synchronizable Under Voltage Protection, Brown-Out
Switching Frequency	400 kHz
Component Count + Extras	24 + 11
Design Author	Texas Instruments
Application / Target Market
Main I.C. Base Part	LM3409HV
Date Created By Author	2009-11
Date Added To Library	2012-10