LM3433SQ-36AEV/NOPB National Semiconductor, LM3433SQ-36AEV/NOPB Datasheet

LM3433SQ-36AEV/NOPB

Manufacturer Part Number

LM3433SQ-36AEV/NOPB

Description

BOARD EVALUATION FOR LM3433SQ

Manufacturer

National Semiconductor

Series

PowerWise®r

Datasheets

1.LM3433SQNOPB.pdf (14 pages)

2.LM3433SQ-36AEVNOPB.pdf (12 pages)

Specifications of LM3433SQ-36AEV/NOPB

Current - Output / Channel

30A

Outputs And Type

1, Non-Isolated

Voltage - Output

Features

Dimmable

Voltage - Input

-9 ~ -14V

Utilized Ic / Part

LM3433

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Other names

LM3433SQ-36AEV

Available stocks

Company

Part Number

Manufacturer

Quantity

Price

Company:

Bonase Electronics (HK) Co., Limited

Part Number:

LM3433SQ-36AEV/NOPB

Manufacturer:

National Semiconductor

Quantity:

135

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LM3433 10A to 40A LED

Driver Evaluation Board

Introduction

The LM3433 is an adaptive constant on-time DC/DC buck

constant current controller designed to drive a high brightness

LED (HB LED) at high forward currents. It is a true current

source that provides a constant current with constant ripple

current regardless of the LED forward voltage drop. The

board can accept an input voltage ranging from -9V to -14V

w.r.t. GND. The output configuration allows the anodes of

multiple LEDs to be tied directly to the ground referenced

chassis for maximum heat sink efficacy when a negative input

voltage is used.

LM3433 High Current Board

Description

The evaluation board is designed to provide a constant cur-

rent in the range of 10A to 60A (although the board is ther-

mally limited to approximately 40A continuous operation) and

can connect directly to a Luminus Devices, Inc. PhlatLight

PT-120 or similar high current LED. It is ideal for pulsing an

LED at 30A or greater for applications such as rear and for-

ward projection. The LM3433 requires two input voltages for

operation. A positive voltage with respect to GND is required

for the bias and control circuitry and a negative voltage with

respect to GND is required for the main power input. This al-

lows for the capability of using common anode LEDs so that

the anodes can be tied to the ground referenced chassis. The

evaluation board only requires one input voltage of -12V with

respect to GND (any high current 12V supply will work). The

positive voltage w.r.t. GND on the board is supplied by the

LM5002 circuit (see below). Initially the output current is set

at the minimum of approximately 10A with the POT P1 fully

counter-clockwise. To set the desired current level a short

may be connected between LED+ and LED-, then use a cur-

rent probe and turn the POT clockwise until the desired

current is reached. PWM dimming FETs are included on-

board for testing when the LED can be connected directly next

to the board. A shutdown test post on J2, ENA, is included so

that startup and shutdown functions can be tested using an

external voltage. Note that the test points for GND and -12V

are for measurement only, the high current input source

should be connected through J1.

LM5002 Circuit

The positive voltage w.r.t. GND on the board is supplied by

the LM5002 circuit. The LM5002 feedback is level shifted so

that the output that supplies the LM3433 bias circuitry will re-

main at +5V w.r.t. GND regardless of where VEE is in the -9V

to -14V range. The LM5002 circuit also provides a UVLO

function to remove the possibility of the LM3433 drawing high

currents at input voltages less than -9V during startup. This

circuit was designed with enough output current to power a

small 5V sideblower fan (Sunon part number B0502AFB2-8)

to help keep the inductor, and therefore the board to some

degree, cooler if extreme ambient temperatures are expect-

ed. One LM5002 circuit can supply enough current to drive

PhlatLight® is a registered trademark of Luminus Devices, Inc.

300894

National Semiconductor

Application Note 1937

Clinton Jensen

January 14, 2010

the positive voltage for multiple LM3433 circuits in a system,

up to approximately 100.

Setting the LED Current

The LM3433 evaluation board is designed so that the LED

current can be set in multiple ways. There is a shunt on J2

initially connecting the ADJ pin to the POT allowing the current

to be adjusted using the POT P1. This POT will apply a volt-

age to the ADJ pin between 0.3V and 1.5V w.r.t. GND to

adjust the voltage across the sense resistor (R

The shunt may also be removed and an external voltage pos-

itive w.r.t. GND can then be applied to the ADJ test point on

the board. A 2mΩ resistor comes mounted on the board (five

10mΩ resistors in parallel) so using the V

in the Typical Performance Characteristics section the current

can be set using the following equation:

Alternatively the shunt can be removed and the ADJ test point

can be connected to the VINX test point to fix V

for 30A output current.

PWM Dimming

The LM3433 is capable of high speed PWM dimming in ex-

cess of 40kHz. Dimming is accomplished by shorting across

the LED with a FET(s). Dimming FETs are included on the

evaluation board for testing LEDs placed close to the board.

The FETs on the evaluation board should be removed if using

dimming FETs remotely placed close to the LED (STRONG-

LY recommended). If the FETs cannot be placed directly next

to the LED then some form of snubber may be required to

prevent damage to the LM3433, LM5111, and LM2937 due

to the large spikes caused by inductance between the LED

and FETs. D4, C17, and R32 may be used to populate a

snubber circuit.

To use the dimming function apply square wave to the PWM

test point on the board that has a positive voltage w.r.t. GND.

When this pin is pulled high the dimming FET is enabled and

the LED turns off. When it is pulled low the dimming FET is

turned off and the LED turns on. A scope plot of PWM dim-

ming is included in the Typical Performance Characteristics

section showing 120Hz dimming at 20% duty cycle.

Reducing Component Count

This board has been optimized to reduce losses in the power

FETs and dimming FETs by using the LM5111 gate drivers

to increase the gate drive current as well as the gate voltage

for minimum R

efficiency can be tolerated when PWM dimming then some

components may be removed. As shipped an LM5111 is used

to drive the PWM FET gates. The LM5111 is powered by us-

ing D6 and C25 to form a charge pump to generate a positive

voltage above GND that is approximately equal to |VEE|. This

voltage is then regulated down to 12V above LED- with the

LM2937 to power the LM5111. The result is high gate drive

current capability and a high gate voltage for the dimming

FETs. With the use of the LM5111s on the main power FETs

DS(ON)

LED

. If more power dissipation and/or lower

= V

SENSE

vs. V

www.national.com

SENSE

ADJ

at 60mV

) R15.

graph

Related parts for LM3433SQ-36AEV/NOPB

LM3433SQ-36AEV/NOPB Summary of contents

Page 1

... One LM5002 circuit can supply enough current to drive PhlatLight® registered trademark of Luminus Devices, Inc. © 2010 National Semiconductor Corporation National Semiconductor Application Note 1937 Clinton Jensen ...

Page 2

LM3433 has enough internal drive current capability to drive the dimming FETs without the use of external compo- nents. The R will increase and the switch transitions will DS(ON) be slower but all related components could be removed. In ...

Page 3

3 www.national.com ...

Page 4

ID Part Number U1 LM3433 U2 LM5002MA U3, U4, U5 LM5111-1MY U6 LM2937IMP-12 C1 C0805C471K5RACTU C2 LMK316BJ476ML-T C3a, C3b 16SH150M C4a, C4b, C4c, GRM32ER61C226KE20L C4d, C4e, C4f C6, C34, C35 GRM32ER61C476ME15L C7, C8, C18 C0805C104J5RACTU C9, C17, C23, OPEN C24, ...

Page 5

ID Part Number Q8, Q9, Q13, OPEN Q14, Q15, Q16, Q17, Q18 Q10, Q11, Q12 MMBT3904 -7 R1 ERJ-6ENF2942V R2 ERJ-6ENF2491V R3, R13, R30, ERJ-6ENF1002V R31 R4 ERJ-6GEYJ393V R5 ERJ-6GEYJ101V R6 ERJ-6ENF1212V R8 ERJ-6ENF2002V R10 ERJ-6ENF4991V R11, R12 ERJ-6ENF6192V R15a, ...

Page 6

Typical Performance Characteristics Efficiency vs 18A, V LED LED 120Hz PWM Dimming Waveform I = 30A nominal 5V -12V LED IN EE Top trace: DIM input, 1V/div, DC Bottom trace ...

Page 7

Layout Top Layer and Top Overlay 7 30089420 www.national.com ...

Page 8

Upper Middle Layer 8 30089421 ...

Page 9

Lower Middle Layer 9 30089422 www.national.com ...

Page 10

Bottom Layer and Bottom Overlay 10 30089423 ...

Page 11

Notes 11 www.national.com ...

Page 12

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

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