HV9931

Features

Constant output current

Large step-down ratio

Unity power factor

Low input current harmonic distortion

Fixed frequency or fixed off-time operation

Internal 450V linear regulator

Input and output current sensing

Input current limit

Enable, PWM and phase dimming

Applications

Offline LED lamps and fixtures

Street lamps

Traffic signals

Decorative lighting

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General Description

The HV9931 is a fixed frequency PWM controller IC designed

to control an LED lamp driver using a single-stage PFC

buckboost-buck topology. It can achieve a unity power factor

and a very high step-down ratio that enables driving a single

high-brightness LED from the 85-264VAC input without a

need for a power transformer. This topology allows reducing

the filter capacitors and using non-electrolytic capacitors to

improve reliability. The HV9931 uses open-loop peak current

control to regulate both the input and the output current. This

control technique eliminates a need for loop compensation,

limits the input inrush current, and is inherently protected from

input under-voltage condition.

Capacitive isolation protects the LED Lamp from failure of the

switching MOSFET. HV9931 provides a low-frequency PWM

dimming input that can accept an external control signal with a

duty ratio of 0-100% and a frequency of up to a few kilohertz.

The PWM dimming capability enables HV9931 phase control

solutions that can work with standard wall dimmers.

Typical Application Circuit

VIN

GATE

CS1

CS2

VDD

PWMD

RT

GND

C2

L1

L2

C1

Q1

D3

D4

VO

+

-

D1

D2

~AC

~AC

HV9931

HV9931 Unity Power Factor LED Lamp Driver