®
RT7304
Primary-Side-Regulation LED Driver Controller
with Active PFC
General Description
Features
Tight LED Current Regulation
The RT7304 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 RT7304 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.
No Opto-Coupler and TL431 Required
Power Factor Correction (PFC)
Quasi-Resonant
Maximum/Minimum Switching Frequency
Clamping
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
The RT7304 embeds comprehensive protection functions
for robust designs, including LED open-circuit protection,
LED short-circuit protection, output diode short-circuit
protection, VDDUnder-Voltage lockout (UVLO), VDDOver-
Voltage Protection (VDD OVP), Over-Temperature
Protection (OTP), and cycle-by-cycle current limitation.
VDD Over-Voltage Protection
Over-Temperature Protection
Cycle-by-Cycle Current Limit
RoHS Compliant and Halogen Free
Marking Information
0H= : Product Code
Applications
0H=DNN
DNN : Date Code
AC/DC LED Lighting driver
Simplified Application Circuit
Flyback Converter
Buck-Boost Converter
D
TX1
BD
TX1
OUT
BD
V
V
Line
OUT-
Line
V
V
OUT+
C
OUT
C
OUT
D
OUT
C
SIN
C
SIN
RT7304
OUT+
RT7304
R
ST
OUT-
R
R
ST
G
R
G
Q1
Q1
GD
CS
GD
CS
Neutral
Neutral
R
PC
R
PC
VDD
VDD
R
CS
R
CS
C
VDD
C
VDD
COMP
ZCD
GND
COMP
ZCD
GND
C
COMP
C
COMP
R
R
ZCD2
R
R
ZCD2
ZCD1
ZCD1
D
AUX
D
AUX
Copyright 2015 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS7304-04 February 2015
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
