LM3402HVEVAL National Semiconductor, LM3402HVEVAL Datasheet

LM3402HVEVAL

Manufacturer Part Number

LM3402HVEVAL

Description

BOARD EVALUATION FOR LM3402HV

Manufacturer

National Semiconductor

Series

PowerSmart®r

Datasheets

1.LM3402MMNOPB.pdf (28 pages)

2.LM3402EVAL.pdf (10 pages)

Specifications of LM3402HVEVAL

Current - Output / Channel

500mA

Outputs And Type

1, Non-Isolated

Voltage - Output

4 V

Features

Dimmable

Voltage - Input

6 ~ 75 V

Utilized Ic / Part

LM3402

Core Chip

LM3402HV

Topology

Buck

Input Voltage

6V To 75V

Dimming Control Type

PWM

Kit Contents

Board

Svhc

No SVHC (15-Dec-2010)

Kit Features

Cycle-by-Cycle Current Limit, Separate PWM Dimming

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Other names

*LM3402HVEVAL

Current page: 1 of 10
Download datasheet (30Mb)

LM3402/02HV Demo Board

Introduction

The LM3402/LM3402HV is a buck regulator derived con-

trolled current source designed to drive a series string of high

power, high brightness LEDs (HBLEDs) such as the Lux-

eon™ I Emitter at forward currents of up to 500 mA. The board

can accept an input voltage ranging from 6V to 42V when

using the LM3402. When using the pin-for-pin compatible

LM3402HV the upper bound of input voltage is 75V. The con-

verter output voltage adjusts as needed to maintain a con-

stant current through the LED array. The LM3402/02HV is a

true step-down regulator with an output voltage range ex-

tending from a V

It can maintain regulated current through any number of LEDs

as long as the combined forward voltage of the array does not

exceed V

Circuit Performance LM3402

The LM3402 circuit and BOM have been designed to provide

a constant forward current of 350 mA to a single LED with a

forward voltage of approximately 3.5V. (Typical of white, blue,

and green LEDs using InGaN technology.) When powered

from a 24V ±5% input the demo board will maintain the aver-

age LED current, I

current, Δi

frequency for the demo board is 600 kHz ± 10% over the input

voltage range of 6V to 42V.

Circuit Performance LM3402HV

The LM3402HV circuit and BOM have been designed to pro-

vide a constant forward current of 350 mA to a single LED

with a forward voltage of approximately 3.5V. When powered

from a 48V ± 5% input the demo board will maintain I

±5% of 350 mA. Ripple current will not exceed 70 mA peak-

to-peak. Switching frequency for the demo board is 250 kHz

±10% over the input voltage range of 6V to 75V.

Connecting to LED Array

The LM3402/02HV demo board includes a female 6-pin SIP,

J1, connector as well as two standard 94mil turret connectors

for the cathode and anode connections of the LED array. Fig-

ure 1 shows the pinout of J1. Solid, 18 or 20 gauge wire with

about 1 cm of insulation stripped away makes a convenient,

solderless connection to J1.

O(MAX)

determined by the minimum off time (typically 300 ns).

O(MAX).

, will not exceed 70 mA peak-to-peak. Switching

O(MIN)

, to within 10% of 350 mA. The ripple

of 200 mV (the reference voltage) to a

201980

to within

National Semiconductor

Application Note 1500

Chris Richardson

June 2007

Setting the LED Current

The default forward current I

350 mA, typical of many 1W LEDs. To adjust this value the

current setting resistor R

following equation:

This resistor should be rated to handle the power dissipation

of the LED current. For example, the closest 5% tolerance

resistor to set an LED current of 350 mA is 0.56 Ω. In steady

state this resistor will dissipate (0.352 x 0.56) = 69 mW, indi-

cating that a resistor with a 1/8W power rating is appropriate.

PWM Dimming

The DIM1 terminal on the PCB provides an input for a pulse

width modulation signal for dimming of the LED array. In order

to fully enable and disable the LM3402/02HV the PWM signal

should have a maximum logic low level of 0.8V and a mini-

mum logic high level of 2.2V. The maximum PWM dimming

frequency, minimum PWM duty cycle and maximum duty cy-

cle are illustrated in Figure 2. PWM frequency should be at

least one order of magnitude below the LM3402/02HV switch-

ing frequency. The interval t

logic high at the DIM pin to the onset of the output current.

The quantities t

output current to slew up to steady state and slew down to

zero, respectively. Typical response times for the standard

LM3402 and LM3402HV demo boards circuits are shown in

the Typical Performance Characteristics section.

and t

SNS

FIGURE 1.

represent the time needed for the

= 220 ns

LED

can be changed according to the

represents the delay from a

delivered to the LED array is

20198001

www.national.com

Related parts for LM3402HVEVAL

LM3402HVEVAL Summary of contents

Page 1

... LED array. Fig- ure 1 shows the pinout of J1. Solid gauge wire with about insulation stripped away makes a convenient, solderless connection to J1. © 2007 National Semiconductor Corporation National Semiconductor Application Note 1500 Chris Richardson June 2007 ...

Page 2

The logic of DIM1 is direct, hence the LM3402/02HV will de- liver regulated output current when the voltage at DIM1 is high, and the current output is disabled when the voltage at DIM1 is low. Connecting a constant logic low ...

Page 3

ID Part Number U1 LM3402 L1 SLF10145T-101M1R0 D1 CMSH1-60M Cf VJ0805Y104KXXAT Cb VJ0805Y103KXXAT Cin C3216X7R1H105M Rsns ERJ6BQFR56V Ron CRCW08054642F Rz CRCW08050R00F DIM1, DIM2 160-1512 GND1, GND2, 160-1026 GND3, VIN, ISNS / 535676-5 FIGURE 3. ...

Page 4

ID Part Number U1 LM3402HV L1 SLF10145T-151MR79 D1 CMSH1-100M Cf VJ0805Y104KXXAT Cb VJ0805Y103KXXAT Cin C3225X7R2A105M Co1 C3216X7R1E225M Rsns ERJ6BQFR68V Ron CRCW08051303F Rz CRCW08050R00F DIM1, DIM2 160-1512 GND1, GND2, 160-1026 GND3, VIN, ISNS / 535676-5 ...

Related keywords

lm3409
lm3401
lm3409hv
lm3402hv
LM3402HVEVAL datasheet
LM3402HVEVAL data sheet
LM3402HVEVAL pdf datasheet
LM3402HVEVAL component
LM3402HVEVAL part
LM3402HVEVAL distributor
LM3402HVEVAL RoHS
LM3402HVEVAL datasheet download

LM3402HVEVAL National Semiconductor, LM3402HVEVAL Datasheet

LM3402HVEVAL

Specifications of LM3402HVEVAL

Related parts for LM3402HVEVAL

LM3402HVEVAL Summary of contents

Page 1

Page 2

Page 3

Page 4

Page 5

Page 6

Page 7

Page 8

Page 9

Page 10

Related keywords