TPS61185 Datasheet, PDF (1/26 Pages) Texas Instruments – WLED Driver for Notebooks with PWM Control Interface

TPS61185
www.ti.com
SLVSAA1A – APRIL 2010 – REVISED MAY 2010
WLED Driver for Notebooks with PWM Control Interface
Check for Samples: TPS61185
FEATURES
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• 4.2 V to 24 V Input Voltage
• Integrated 2 A/40 V MOSFET
• 600 kHz to 2 MHz Programmable Switching
Frequency
• Adaptive Boost Output for Best Efficiency
• Design to Use Small L-C Components
• Integrated Loop Compensation
• Eight 25 mA Current Sinks
• Up to 10 WLED in Series
• 1% Current Matching and Accuracy
• PWM Brightness Interface Control
• 200 mV Ripple Under PWM Dimming
• Driver for Input/Output Isolation PFET
• Programmable Over Voltage Threshold
• 100 Hz to 5 kHz Programmable PWM Dimming
Frequency
• Up to 20 kHz Direct PWM Dimming Frequency
• Enhanced Electrostatic Discharge Immunity
Level
• Built-in WLED Open/Short Protection
• Over Temperature Protection
• 24 Pin 4 mm × 4 mm QFN Package
APPLICATIONS
• Notebook LCD Display Backlight
DESCRIPTION
The TPS61185 IC provides highly integrated
solutions for large-size LCD backlighting. This device
has a built-in high efficiency boost regulator with
integrated 2 A/40 V power MOSFET. The eight
current sink regulators provide high precision current
regulation and matching. In total, the device can
support up to 80 LEDs. In addition, the boost output
automatically adjusts its voltage to the WLED forward
voltage to improve efficiency.
The TPS61185 supports the PWM method for
brightness dimming. Simply tie the unused current
sinks to ground if fewer than eight are needed. During
PWM dimming, each of the eight current regulators is
turned on/off at the duty cycle determined by an
external pulse width modulation (PWM) signal input to
the PWM pin. The frequency at which each current
regulator turns on/off follows the input PWM signal on
the PWMIN pin if the MODE pin is grounded. If the
MODE pin is left floating or tied high, the regulators
turn on/off at the frequency programmed by an
external resistor on the FPWMO pin.
The TPS61185 IC supports boost switch frequency
programming from 600kHz to 2MHz by an external
resistor on the FSW pin. The device also provides a
driver output for an optional external PFET connected
between the input and inductor for truly disconnecting
the battery from LED during the shutdown or fault
protection. The device integrates resistor
programmable over-voltage protection, soft-start, and
thermal shutdown.
The TPS61185 IC has a built-in linear regulator to
power the internal circuits of the IC. The device is in a
4 mm × 4 mm QFN package.
4.2V~24V
C1
4.7 mF
C4
1 mF
C3
1 mF
Open Freq Pro
GND Direct
R1
62 KW
R2
604 KW
Typical Application Circuit
L1
10 mH
D1
C2
4.7 mF
R3
1 MW
FAULT
VIN
VDD
SW1 SW2
PGND1
PGND2
TPS61185 ^OVP
R4
54.9 KW
EN
PWMIN
FPWMO
MODE
ISET
FSW
AGND
IFB1
IFB2
IFB3
IFB4
IFB5
IFB6
IFB7
IFB8
R5
715 KW
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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 © 2010, Texas Instruments Incorporated