®
RT8479C
Two-Stage Hysteretic LED Driver with Internal MOSFETs
General Description
Features
Two-Stage Topology (Boost + Buck)
The RT8479C is a two-stage controller with dual
MOSFETs and consists of a Boost converter (first stage)
and a Buck converter (second stage). The advantage of
two-stage topology is highly compatible with ET (Electronic
Transformer) and extremely high Power Factor
performance in MR16 / AR111 lighting market fields
applications.
Dual MOSFETs Inside
Wide Input Voltage Range : 4.5V to 36V
Excellent Power Factor
Programmable Boost Output Voltage
Independent Dual Stage Function
Programmable LED Current with 5% LED Current
Accuracy
The first stage is a Boost converter for constant voltage
output with inductor peak current over-current protection.
The second stage is a Buck converter for constant output
current by typical constant peak current regulation.
Input Under-Voltage Lockout Detection
Thermal Shutdown Protection
Ordering Information
RT8479C
The RT8479C is equipped with dual output gate drivers
for internal power MOSFETs.
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
The RT8479C is available in the SOP-8 (Exposed Pad)
package.
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Applications
Richtek products are :
MR16 Lighting
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Signage andDecorative LEDLighting
Architectural Lighting
High Power LED Lighting
Low Voltage Industrial Lighting
Indicator and Emergency Lighting
Automotive LED Lighting
Simplified Application Circuit
D5
L1
VCC
C
OUT
R1
R2
RT8479C
D1
D2
R
SENSE
OVP
VCC
LED+
LED-
VL
AC 12V
VN
ISN
D6
C
IN
C3
CREG
LX1
C2
VCOMP
ACTL
D3
D4
L2
To
Dimming
C1
LX2
GND
Copyright 2014 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS8479C-04 August 2014
www.richtek.com
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