Rev. 1.00

1�

���i� ��� �011

Rev. 1.00

19

���i� ��� �011

HT7L4091

Universal Step-Down PWM Control

For High Brightness LED Lighting Control

Input voltage vs. LED Current

160

210

260

310

360

410

460

80

130

180

230

280

Vac(V)

16S LED

14S LED

12S LED

10S LED

8S LED

LED String vs. LED current

160

210

260

310

360

410

460

6

8

10

12

14

16

18

LED String

260Vac

85Vac

170Vac

110Va

220Vac

Typical Application Circuit

L

D1

MOSFET

CS

GND

RT

LD

C7

Rcs

�C

EMI

Lc

Lc

Ca1

Ca�

C1

0.1uF

400V

1uF/50V

0.1uF

��uF

400V

Essentia� com�onents

Used optional components

Unused optional components

Zin

5�F

This typical application circuit uses a fundamental buck converter circuit. Adding a CO capacitor

can reduce the LED current ripple or reduce the inductor size while adding the RC and CC

components can reduce spikes on the CS pin.

If frequency jittering is considered to reduce EMI an optional 5pF CT may be used to stabilise the

effect.