LED Driver. RT8479C Datasheet

RT8479C Driver. Datasheet pdf. Equivalent

RT8479C Datasheet
Recommendation RT8479C Datasheet
Part RT8479C
Description Two-Stage Hysteretic LED Driver
Feature RT8479C; ® RT8479C Two-Stage Hysteretic LED Driver with Internal MOSFETs General Description The RT8479C is.
Manufacture Richtek
Datasheet
Download RT8479C Datasheet




Richtek RT8479C
®
RT8479C
Two-Stage Hysteretic LED Driver with Internal MOSFETs
General Description
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.
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.
The RT8479C is equipped with dual output gate drivers
for internal power MOSFETs.
The RT8479C is available in the SOP-8 (Exposed Pad)
package.
Applications
MR16 Lighting
Signage and Decorative LED Lighting
Architectural Lighting
High Power LED Lighting
Low Voltage Industrial Lighting
Indicator and Emergency Lighting
Automotive LED Lighting
Features
Two-Stage Topology (Boost + Buck)
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
Input Under-Voltage Lockout Detection
Thermal Shutdown Protection
Ordering Information
RT8479C
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
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.
Simplified Application Circuit
L1 D5
VL
AC 12V
VN
D1 D2
CIN
D3 D4
R1
R2
C1
To
Dimming
RT8479C
OVP
VCC
ISN
LX1 CREG
VCOMP
ACTL
LX2
GND
VCC
COUT
RSENSE
LED+
C3
C2 LED-
L2
D6
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8479C-04 August 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8479C
RT8479C
Marking Information
RT8479CGSP : Product Number
RT8479C
GSPYMDNN
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
LX1
OVP
ACTL
VCOMP
8
27
GND
36
9
45
LX2
CREG
VCC
ISN
SOP-8 (Exposed Pad)
Functional Pin Description
Pin No.
Pin Name
Pin Function
1 LX1 Switch Node. The first stage internal MOSFET Drain.
2
OVP
Over-Voltage Protection Sense Input.
3
ACTL
Analog / PWM Dimming Control Input. Connect to CREG if not used.
4
VCOMP
Compensation Node. A compensation network between VCOMP and GND is
needed.
5 ISN
6 VCC
7 CREG
8 LX2
9 (Exposed Pad) GND
LED Negative Current Sense Input.
Supply Voltage Input. For good bypass, place a ceramic capacitor near the
VCC pin.
Internal Regulator Output. Place an 1F capacitor between the CREG and
GND pins.
Switch Node. The second stage internal MOSFET Drain.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Function Block Diagram
ISN VCC
ACTL
OVP
VCOMP
-130mV
ACTL
Logic
V
VCC
UV/OV
Core
Logic
EN2
EN1
+
-
EN2
EN1
Regulator
CREG
LX2
LX1
GND
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8479C-04 August 2014



Richtek RT8479C
Operation
The RT8479C VCC is supplied from the first stage Boost
output.
The first stage is a constant output voltage Boost topology
and senses the peak inductor current for over-current
protection with excellent Power Factor.
The second stage is a constant output current Buck
topology. The current sense voltage threshold between
the VCC and ISN pins is only 130mV to reduce power
loss.
RT8479C
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8479C-04 August 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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