RT7310

Copyright © 2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS7310-00

October

2014

www.richtek.com

1

Phase-Cut Dimmable Primary-Side Regulation

LED Driver Controller with Active PFC

General Description

The RT7310 is a high power factor constant current

LED driver which is optimized for the compatibility with

phase-cut dimmers. 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), RT7310 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 RT7310 supports phase-cut dimmers, including

leading-edge (TRIAC) and trailing-edge dimmers.

RT7310 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

(OVP),

Over-Temperature

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

Features



Supporting Phase-Cut Dimmers



Tight LED Current Regulation



No Opto-Coupler and TL431 Required



Power Factor Correction (PFC)



Quasi-Resonant



Maximum/Minimum Switching Frequency

Clamping



Maximum/Minimum On-Time Limitation



Wide VDD Range (up to 25V)



Multiple Protection Features :



LED Open-Circuit Protection



LED Short-Circuit Protection



Output Diode Short-Circuit Protection



VDD Under-Voltage Lockout



VDD Over-Voltage Protection



Over-Temperature Protection



Cycle-by-Cycle Current Limitation

Application

 Phase-Cut Dimmable LED luminaries

Simplified Application Circuit

Flyback Converter

GD

CS

VDD

RT7310

ZCD

BD

COMP

GND

Q1

Q2

Line

Neutral

L1

Tapped-Inductor Buck-Boost Converter

GD

CS

VDD

RT7310

ZCD

BD

COMP

GND

Q1

Q2

Line

Neutral

L1