RT8476 Datasheet PDF - Richtek

www.Datasheet-PDF.com

RT8476
Richtek

Part Number RT8476
Description Two-Stage Hysteretic LED Driver Controller
Page 16 Pages


RT8476 datasheet pdf
Download PDF
RT8476 pdf
View PDF for Mobile

No Preview Available !

®
RT8476
Two-Stage Hysteretic LED Driver Controller
General Description
The RT8476 is a two-stage controller with dual gate drivers
consist of a Boost converter (first stage) and a Buck
converter (second stage). The advantage of the two-stage
topology is highly compatible with ET (Electronic
Transformer) in MR16 / AR111 lighting market field
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 RT8476 is equipped with dual output gate drivers for
external power MOSFETs, suitable for higher power
applications.
The RT8476 is available in the SOP-8 and SOP-8 (Exposed
pad) packages.
Applications
z MR16 Lighting
z Signage and Decorative LED Lighting
z Architectural Lighting
z High Power LED Lighting
z Low Voltage Industrial Lighting
z Indicator and Emergency Lighting
z Automotive LED Lighting
Features
z Two-Stage Topology (Boost + Buck)
z Wide Input Voltage Range : 4.5V to 40V
z Adjustable Peak Input Current Control
z Adjustable Boost Output Voltage
z Independent Dual Stage Function
z Adjustable LED Current with ±5% LED Current
Accuracy
z Input Under Voltage Lockout Detection
z Thermal Shutdown Protection
z SOP-8 and SOP-8 (Exposed Pad) Packages
z RoHS Compliant and Halogen Free
Ordering Information
RT8476
Package Type
S : SOP-8
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
VL
AC 12V
VN
L1 D6
D1 D2
CIN
D3 D4
COUT R4
RT8476
OVP
VCC
R5
M1
ISN
CREG
GATE1
CS
R6 GATE2
GND
RSENSE
D7
C3 L2
M2
LED+
C6
LED-
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8476-00 April 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



No Preview Available !

RT8476
Marking Information
RT8476GS
RT8476
GSYMDNN
RT8476GS : Product Number
YMDNN : Date Code
RT8476GSP
RT8476
GSPYMDNN
RT8476GSP : Product Number
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
GATE1
CS
OVP
GND
2
3
4
8 GATE2
7 CREG
6 VCC
5 ISN
SOP-8
GATE1
CS
OVP
GND
8
27
GND
36
9
45
GATE2
CREG
VCC
ISN
SOP-8 (Exposed Pad)
Functional Pin Description
Pin No.
SOP-8
SOP-8
(Exposed Pad)
Pin Name
1 1 GATE1
2 2 CS
3 3 OVP
4
4,
9 (Exposed Pad)
GND
5 5 ISN
6 6 VCC
7 7 CREG
8 8 GATE2
Pin Function
Gate Driver Output for External MOSFET Switch in the First Stage.
Current Sense Input for External MOSFET Switch.
Over Voltage Protection Sense Input.
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
LED Current Sense Amplifier Negative Input.
Supply Voltage Input. For good bypass, place a ceramic capacitor
near the VCC pin.
Internal Regulator Output. Place an 1μF capacitor between the
CREG and GND pins.
Gate Driver Output for External MOSFET Switch in the Second
Stage.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8476-00 April 2013



No Preview Available !

Function Block Diagram
ISN VCC
-130mV
VCC
V
UV
Regulator
OVP
CS
Core
Logic
EN2
EN2
EN1
EN1
+
-
V 240mV
CREG
CREG
GATE2
GATE1
GND
RT8476
Operation
The VCC of the RT8476 is supplied from the first stage
Boost output. The first stage is a constant output voltage
Boost topology. The CS pin senses the peak inductor
current for over current protection. The peak inductor
current level can be adjusted by the sense resistor
between MOSFET Source and GND pins.
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.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8476-00 April 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3



No Preview Available !

RT8476
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VCC to GND ----------------------------------------------------------------------------------- 0.3V to 45V
z CS, GATE1, GATE2, CREG, OVP to GND -------------------------------------------------------------------------- 0.3V to 6V
z VCC to ISN ----------------------------------------------------------------------------------------------------------------- 1V to 3V
z Power Dissipation, PD @ TA = 25°C
SOP-8 ------------------------------------------------------------------------------------------------------------------------ 0.53W
SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------- 3.44W
z Package Thermal Resistance (Note 2)
SOP-8, θJA ------------------------------------------------------------------------------------------------------------------ 188°C/W
SOP-8 (Exposed Pad), θJA ---------------------------------------------------------------------------------------------- 29°C/W
SOP-8 (Exposed Pad), θJC --------------------------------------------------------------------------------------------- 2°C/W
z Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
z Storage Temperature Range -------------------------------------------------------------------------------------------- 65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Model) ----------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, VCC ---------------------------------------------------------------------------------------------- 4.5V to 40V
z Junction Temperature Range -------------------------------------------------------------------------------------------- 40°C to 125°C
z Ambient Temperature Range -------------------------------------------------------------------------------------------- 40°C to 85°C
Electrical Characteristics
(VCC = 10V, No Load, CLOAD = 1nF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min Typ Max Unit
Supply Voltage
CREG UVLO_ ON
VUVOL_ON CS/OVP = 0V
4 4.3 4.6 V
CREG UVLO_ OFF
VUVOL_OFF CS/OVP = 0V
-- 4.2 --
V
Supply Current
VCC Shutdown Current
ISHDN
Before Start-Up, VCC = 3.5V
-- 10 -- μA
VCC Quiescent Current
IQ
After Start-Up, VCC = 5V, GATE1
and GATE2 Stand Still
--
1.5
--
mA
Internal Reference Voltage VCREG
-- 5 -- V
Internal Reference Voltage
ICREG = 20mA
-- 4.9 --
V
Current Sense Comparator
CS Threshold Voltage
CS Pin Leakage Current
VCS
ICS
215 240 265 mV
-- 1 -- μA
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
www.richtek.com
4
is a registered trademark of Richtek Technology Corporation.
DS8476-00 April 2013



RT8476 datasheet pdf
Download PDF
RT8476 pdf
View PDF for Mobile


Related : Start with RT847 Part Numbers by
RT8470 High Brightness LED Driver RT8470
Richtek
RT8470 pdf
RT8471 High Brightness LED Driver RT8471
Richtek
RT8471 pdf
RT8472 High Brightness LED Driver RT8472
Richtek
RT8472 pdf
RT8473 High Brightness LED Driver RT8473
Richtek
RT8473 pdf
RT8474 High Voltage Multiple-Topology LED Driver RT8474
Richtek
RT8474 pdf
RT8474A High Voltage Multiple-Topology LED Driver RT8474A
Richtek
RT8474A pdf
RT8475 High Voltage High Current LED Driver Controller RT8475
Richtek
RT8475 pdf
RT8476 Two-Stage Hysteretic LED Driver Controller RT8476
Richtek
RT8476 pdf

Index :   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z   

This is a individually operated, non profit site. If this site is good enough to show, please introduce this site to others.
Since 2010   ::   HOME   ::   Contact