RT7302

®

DS7302-03 May 2015

www.richtek.com

1

©

Copyright 2015 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Primary-Side-Regulation Dimmable LED Driver Controller

with Active PFC

General Description

The RT7302 is a constant current LED driver with active

power factor correction. It supports high power factor

across a wide range of line voltages, and it drives the

converter in the Quasi-Resonant (QR) mode to achieve

higher efficiency. By using Primary Side Regulation (PSR),

the RT7302 controls the output current accurately without

a shunt regulator and an opto-coupler at the secondary

side, reducing the external component count, the cost,

and the volume of the driver board.

The RT7302 is designed to be compatible with PWM

Dimming. The output current can be modulated by the

duty ratio of the external PWM dimming signal.

An in-house design High Voltage (HV) start-up device is

integrated in the RT7302 to minimize the power loss and

shorten the start-up time.

The RT7302 embeds comprehensive protection functions

for robust designs, including LED open-circuit protection,

LED short-circuit protection, output diode short-circuit

protection, VDD Under-Voltage Lockout (UVLO), VDD

Over-Voltage Protection (VDD OVP), Over-Temperature

Protection (OTP), and cycle-by-cycle current limitation.

Features

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Tight LED Current Regulation

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No Opto-Coupler and TL431 Required

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Power Factor Correction (PFC)

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Compatible with PWM Dimming

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Built-in HV Start-up Device

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Quasi-Resonant

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Maximum/Minimum

Switching

Frequency

Clamping

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Input Voltage Feed-Forward Compensation

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Maximum/Minimum On-Time Limitation

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Wide VDD Voltage Range (up to 25V)

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Multiple Protection Features

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LED Open-Circuit Protection

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LED Short-Circuit Protection

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Output Diode Short-Circuit Protection

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VDD Under-Voltage Lockout

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VDD Over-Voltage Protection

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Over-Temperature Protection

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Cycle-by-Cycle Current Limit

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RoHS Compliant and Halogen Free

Applications

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AC/DC LED Lighting driver

Flyback Converter

Buck-Boost Converter

Simplified Application Circuit

MULT

COMP

GND

GD

CS

VDD

RT7302

HV

TX1

ZCD

Line

Neutral

BD

Q1

MULT

COMP

GND

GD

CS

VDD

RT7302

HV

TX1

ZCD

Line

Neutral

BD

Q1