LM3402 datasheet(7/18 Pages) NSC

Numer części	LM3402

Szczegółowy opis	LM3402/LM3404 Fast Dimming and True Constant LED Current Evaluation Board

Download	18 Pages

Scroll/Zoom	100%

Producent	NSC [National Semiconductor (TI)]

Strona internetowa	http://www.national.com

Logo

7 / 18 page

Example 2 Ripple Current

V

IN (V)

V

OUT (V)

Δi

L (A)

Three Series LEDs

36

10.4

0.192

48

10.4

0.211

60

10.4

0.223

Four Series LEDs

36

13.8

0.166

48

13.8

0.192

60

13.8

0.208

Four Series LEDs

36

17.2

0.141

48

17.2

0.173

60

17.2

0.193

Calculate R

SNS

Calculate R

SNS at VIN typical (48V), with four series LEDs

(13.8V = V

OUT), and average LED current (IF) set to 500 mA.

•

I

F = 500 mA

•

V

IN = 48V

•

V

OUT = 13.8V

•

L = 68 µH

•

t

D = 220 ns

•

t

ON = 382 ns

R

SNS = 446 mΩ

Calculate Average Current through LED

All combinations of V

IN, VOUT with RSNS = 446 mΩ

Example 2 Average LED Current

V

IN (V)

V

OUT (V)

I

F (A)

Three Series LEDs

36

10.4

0.511

48

10.4

0.521

60

10.4

0.526

Four Series LEDs

36

13.8

0.487

48

13.8

0.500

60

13.8

0.508

Five Series LEDs

36

17.2

0.463

48

17.2

0.479

60

17.2

0.489

In this application you can see that there is a difference of 63

mA between the low and high of the average LED current.

Modified COT Application Circuit

With the addition of one pnp transistor and one resistor (Q1

and R3) the average current through the LEDs can be made

to be more constant over input and output voltage variations.

Refer to page one figure 1. Resistor R

ON (R2) and Q1 turn the

t

ON equation into:

Ignore the PNP transistor’s V

BE voltage drop.

Design to the same criteria as the previous example with the

improved application and compare results.

7

www.national.com

Podobny numer części - LM3402

Producent	Numer części	Arkusz danych	Szczegółowy opis
National Semiconductor ...	LM3402	844Kb / 22P	0.5A Constant Current Buck Regulator for Driving High Power LEDs
Texas Instruments	LM3402	570Kb / 30P	[Old version datasheet] LM3402/LM3402HV 0.5A Constant Current Buck Regulator for Driving High Power LEDs
	LM3402	1Mb / 38P	[Old version datasheet] 0.5A Constant Current Buck Regulator for Driving High Power LEDs
	LM3402	1Mb / 36P	[Old version datasheet] 0.5A Constant Current Buck Regulator for Driving High Power LEDs
	LM3402	1Mb / 39P	[Old version datasheet] 0.5A Constant Current Buck Regulator

More results

Podobny opis - LM3402

Producent	Numer części	Arkusz danych	Szczegółowy opis
Shenzhen Huazhimei Semi...	HM7138	375Kb / 7P	PWM dimming LED constant current driver
Unisonic Technologies	L3060	249Kb / 5P	HIGH DIMMING RATIO LED CONSTANT CURRENT DRIVER
E-CMOS Corporation	EC4215	257Kb / 6P	Constant Current LED Driver with PWM Dimming
Shenzhen Huazhimei Semi...	HM3343	1Mb / 10P	PWM dimming LED constant current driver chip
ON Semiconductor	CAT4002A	183Kb / 11P	Constant Current LED Driver with 32 Dimming Levels and Rset July, 2010 ??Rev. 0
ON Semiconductor	NCL2801LED2GEVB	1Mb / 14P	Deep Dimming LED Driver 150 W Evaluation Board March, 2020 ??Rev. 1
Shenzhen Huazhimei Semi...	HM7236	672Kb / 7P	PWM dimming linear buck LED constant current driver
New Japan Radio	NJW4615A	70Kb / 4P	Constant Current LED Driver with PWM Dimming Control
STMicroelectronics	STEVAL385LED4CH	504Kb / 10P	Adjustable LED current and dimming May 2014 Rev 2
STMicroelectronics	STEVAL-ILL066V1	245Kb / 12P	Adjustable LED current and dimming December 2014 Rev 2

More results

LM3402 Arkusz danych(PDF) 7 Page - National Semiconductor (TI)

LM3402 Arkusz danych(HTML) 7 Page - National Semiconductor (TI)

Podobny numer części - LM3402

Podobny opis - LM3402

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Arkusz danych Pobierz

Link URL