TPS65146
www.ti.com ........................................................................................................................................................................................... SLVS869–NOVEMBER 2008
Compact LCD Bias IC with LDO, VCOM Buffer and Reset Function
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FEATURES
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LCD Discharge Function
Overvoltage Protection
Thermal Shutdown
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2.5V to 6.0V Input Voltage Range
16.5V Boost Converter With 2A Switch Current
650kHz/1.2MHz Selectable Switching
Frequency
Undervoltage Lockout
24-Pin 4×4mm QFN Package
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Adjustable Soft-Start for the Boost Converter
500mA LDO
APPLICATIONS
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Notebook PC
Reset Function (XAO Signal)
Regulated VGH
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Monitor
Gate Voltage Shaping
VCOM Buffer
DESCRIPTION
The TPS65146 offers a very compact power supply solution designed to supply the LCD bias voltages required
by TFT (Thin Film Transistor) LCD panels running from a typical 3.3 V or 5 V supply rail. The device integrates a
step-up converter for VS (Source Driver voltage), a positive charge pump regulator for VGH (Gate Driver High
voltage), a logic voltage rail using an integrated LDO and a Vcom buffer driving the LCD backplane. In addition to
that, a gate voltage shaping block is integrated for VGH, modulating the signal (into VGHM) with high flexibility by
using a logic input VFLK and an external discharge resistor connected to RE pin. Also, an external discrete
negative charge pump can be set using the boost converter of the TPS65146 to generate VGL (Gate Driver Low
voltage). The integrated reset function together with the LCD discharge function available in the TPS65146
provide the signals enabling the discharge of the LCD TFT pixels when powering-off. The device includes safety
features like overvoltage protection (OVP), as well as thermal shutdown.
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Boost Converter
and
Over Voltage Protection
V
V
S
IN
9 V/300 mA
3.3 V
Positive Charge Pump Regulator,
Gate Voltage Shaping
and
LCD Discharge Function
V
GHM
20 V/±0 mA
V
LVOUT
LDO
2.5 V/500 mA
VCOM Buffer
(unity gain)
V
COM
±±20 mA
Reset function
XAO
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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 © 2008, Texas Instruments Incorporated