NR030805

Initial Release

3-Pin Switch-Mode LED Lamp Driver IC

Features

Constant Output Current:

o

HV9921 – 20mA

o

HV9922 – 50mA

Universal 85-264VAC Operation

Fixed OFF-Time Buck Converter

Internal 500V Power MOSFET

Applications

Decorative Lighting

Low Power Lighting Fixtures

General Description

The HV9921/22 are pulse width modulated (PWM)

high-efficiency LED driver control ICs. They allow

efficient operation of LED strings from voltage

sources ranging up to 400VDC. The HV9921/22

include an internal high-voltage switching MOSFET

10

µs. The LED string is driven at constant current,

thus providing constant light output and enhanced

reliability. The output current is internally fixed at

20mA for HV9921 and 50mA for HV9922. The peak

current control scheme provides good regulation of

the output current throughout the universal AC line

voltage range of 85 to 264VAC or DC input voltage

of 20 to 400V.

Typical Application Circuit

HV9921/22

NR042205

~

~

AC

1

3

HV9921/22

D1

L1

-

BR1

U1

2

DRAIN

GND