TPS61181A Datasheet, PDF (1/28 Pages) Texas Instruments – WLED DRIVER FOR NOTEBOOK DISPLAY

TPS61181A
www.ti.com
SLVSAN6A – FEBRUARY 2011 – REVISED MARCH 2011
WLED DRIVER FOR NOTEBOOK DISPLAY
Check for Samples: TPS61181A
FEATURES
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• 4.5 V to 24 V Input Voltage
• 38V Maximum Output Voltage
• Integrated 1.5 A/40 V MOSFET
• 1.0-MHz Switching Frequency
• Adaptive Boost Output to WLED Voltages
• Small External Components
• Integrated Loop Compensation
• Six Current Sinks of 30 mA
• Up to 10 WLED in Series
• 1% Typical Current Matching and Accuracy
• Up to 1000:1 PWM Brightness Dimming
• Minimized Output Ripple Under PWM Dimming
• Driver for Input/Output Isolation PFET
• True Shutdown
• Over Voltage Protection
• WLED Open/Short Protection
• Built-in Soft Start
• 16L 3 mm×3 mm QFN
APPLICATIONS
• Notebook LCD Display Backlight
• UMPC LCD Display Backlight
• Backlight for Media Form Factor LCD display
DESCRIPTION
The TPS61181A IC provides highly integrated
solutions for media size LCD backlighting. These
devices have a built-in high efficiency boost regulator
with integrated 1.5A/40V power MOSFET. The six
current sink regulators provide high precision current
regulation and matching. In total, the device can
support up to 60 WLEDs. In addition, the boost output
automatically adjusts its voltage to the WLED forward
voltage to improve efficiency.
The devices support pulse width modulation (PWM)
brightness dimming. During dimming, the WLED
current is turned on/off at the duty cycle and
frequency determined by the PWM signal input to the
DCRTL pin. One potential issue of PWM dimming is
audible noise from the output ceramic capacitors. The
TPS61181A is designed to minimize this output AC
ripple across a wide dimming duty cycle and
frequency range and therefore, reduce this audible
noise.
The TPS61181A provides a driver output for an
external PFET connected between the input and
inductor. During short circuit or over-current
conditions, the IC turns off the external PFET and
disconnects the battery from the WLEDs. The PFET
is also turned off during IC shutdown (thereby giving
"true" shutdown) to prevent any leakage current from
the battery. The device also integrates over-voltage
protection, soft-start and thermal shutdown.
The TPS61181A has a built-in linear regulator for the
IC supply. The devices are in a 3×3 mm QFN
package.
TPS61181A TYPICAL APPLICATION
4.5 V to 24 V
L1
10 µH
C2
D1 _{4.7 µF 10 WLED in series, 120 mA total}
C1
4.7 µF
R2
51 W
Fault
SW
C3
1 µF
EN
PWM Dimming
VBAT
Cin
C4
0.1 µF
TPS61181A
EN
DCTRL
ISET
R1
62 KW
VO
IFB1
IFB2
IFB3
IFB4
IFB5
IFB6
PGND
GND
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011, Texas Instruments Incorporated