RT8511B WLED Driver Datasheet

RT8511B Datasheet, PDF, Equivalent


Part Number

RT8511B

Description

43V Asynchronous Boost WLED Driver

Manufacture

Richtek

Total Page 11 Pages
Datasheet
Download RT8511B Datasheet


RT8511B
®
RT8511B
43V Asynchronous Boost WLED Driver
General Description
The RT8511B is an LED driver IC that can support up to
10 WLED in series. It is composed of a current mode
boost converter integrated with a 43V/2.2A power switch
running at a fixed 500kHz frequency and covering a wide
VIN range from 2.7V to 24V.
The white LED current is set with an external resistor, and
the feedback voltage is regulated to 200mV (typ.). During
operation, the LED current can be controlled by the PWM
input signal in which the duty cycle determines the
feedback reference voltage.
For brightness dimming, the RT8511B is able to maintain
steady control of the LED current. Therefore, no audible
noises are generated on the output capacitor. The RT8511B
also has programmable over voltage pin to prevent the
output from exceeding absolute maximum ratings during
open LED conditions. The RT8511B is available in
WDFN-8L 2x2 package.
Ordering Information
RT8511B
Package Type
QW : WDFN-8L 2x2 (W-Type)
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.
Features
Wide Input Voltage Range : 2.7V to 24V
High Output Voltage : up to 43V
Direct PWM Dimming Control and Frequency from
100Hz to 8kHz
Internal Soft-Start and Compensation
200mV Reference Voltage
PWM Dimming with Internal Filter
Programmable Over Voltage Protection
Over Temperature Protection
Current Limit Protection
Thin 8-Lead WDFN Package
RoHS Compliant and Halogen Free
Applications
UMPC and Notebook Computer Backlight
GPS, Portable DVD Backlight
Pin Configurations
(TOP VIEW)
OVP 1
FB 2
DIMC 3
GND 4
8 EN
7 PWM
6 VIN
9 5 LX
WDFN-8L 2x2
Marking Information
0F : Product Code
0FW
W : Date Code
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8511B-05 February 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1

RT8511B
RT8511B
Typical Application Circuit
VIN
4.2V to 24V
Chip Enable
PWM
100Hz to 8kHz
L
10µH
D
CIN
1µF x 2
RT8511B
6 VIN
LX 5
8 EN
OVP 1
R2
3.3M
R1
100k
CDIMC
1µF
7 PWM
3 DIMC
FB 2
4, 9 (Exposed Pad)
GND
COUT
1µF x 2
VOUT
: ::
: : : WLEDs
: ::
: ::
RSET
3.3
Figure 1. Typical Application Circuit of Normal Operation
L
VLED
2.7V to 24V
CLED
1µF x 2
10µH
RT8511B
VIN
2.7V to 4.2V
6 VIN
CIN
1µF
LX 5
OVP 1
Chip Enable
8 EN
D
R2
3.3M
R1
100k
PWM
100Hz to 8kHz
CDIMC
1µF
7 PWM
3 DIMC
FB 2
GND 4, 9 (Exposed Pad)
VOUT
COUT
1µF x 2
: ::
: : : WLEDs
: ::
: ::
RSET
3.3
Figure 2. Typical Application Circuit of Low Voltage Operation
Functional Pin Description
Pin No.
Pin Name
Pin Function
1
OVP
Over Voltage Protection for Boost Converter. The detecting threshold is 1.2V.
2 FB Feedback. Connect a resistor between this pin and GND to set the LED current.
3
DIMC
PWM Filter. Filter the PWM signal to a DC voltage.
4
GND
Ground.
5 LX
Switch Node for Boost Converter.
6 VIN Power Supply Input.
7
PWM
Dimming Control Input.
8 EN Chip Enable (Active High) for Boost Converter.
9 (Exposed Pad) GND
The exposed pad must be soldered to a large PCB and connected to AGND for
m aximum power dissipation.
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8511B-05 February 2015


Features ® RT8511B 43V Asynchronous Boost WLED Driver General Description The RT8511B is an LED driver IC that can support u p to 10 WLED in series. It is composed of a current mode boost converter integ rated with a 43V/2.2A power switch runn ing at a fixed 500kHz frequency and cov ering a wide VIN range from 2.7V to 24V . The white LED current is set with an external resistor, and the feedback vol tage is regulated to 200mV (typ.). Duri ng operation, the LED current can be co ntrolled by the PWM input signal in whi ch the duty cycle determines the feedba ck reference voltage. For brightness di mming, the RT8511B is able to maintain steady control of the LED current. Ther efore, no audible noises are generated on the output capacitor. The RT8511B al so has programmable over voltage pin to prevent the output from exceeding abso lute maximum ratings during open LED co nditions. The RT8511B is available in W DFN-8L 2x2 package. Ordering Informati on RT8511B Package Type QW : WDFN-8L 2x2 (W-Type) Lead Platin.
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