RT7302 Datasheet, PDF (1/15 Pages) Richtek Technology Corporation – Primary-Side-Regulation Dimmable LED Driver Controller

®
RT7302
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
 Tight LED Current Regulation
 No Opto-Coupler and TL431 Required
 Power Factor Correction (PFC)
 Compatible with PWM Dimming
 Built-in HV Start-up Device
 Quasi-Resonant
 Maximum/Minimum Switching Frequency
Clamping
 Input Voltage Feed-Forward Compensation
 Maximum/Minimum On-Time Limitation
 Wide VDD Voltage 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 Limit
 RoHS Compliant and Halogen Free
Applications
 AC/DC LED Lighting driver
Simplified Application Circuit
Flyback Converter
Buck-Boost Converter
Line
Neutral
BD
CSIN RM1 RHV
RT7302
HV
GD
MULT
RM2
RPC
CS
TX1
DOUT
VOUT+
COUT
VOUT-
Q1
COMP
RCS
CCOMP
GND
VDD
ZCD
DAUX
CVDD
RZCD1
RZCD2
Line
Neutral
BD
CSIN RM1 RHV
RT7302
HV
GD
MULT
RM2
RPC
CS
TX1
Q1
DOUT
VOUT-
COUT
VOUT+
COMP
RCS
CCOMP
GND
VDD
ZCD
DAUX
CVDD
RZCD1
RZCD2
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS7302-03 May 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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