TPS65148 Datasheet, PDF (1/30 Pages) Texas Instruments – Compact TFT LCD Bias IC for Monitor with VCOM Buffer, Voltage Regulator for Gamma Buffer and Reset Function

TPS65148
www.ti.com ........................................................................................................................................................................................................ SLVS904 – MAY 2009
Compact TFT LCD Bias IC for Monitor with VCOM Buffer, Voltage Regulator for Gamma
Buffer and Reset Function
FEATURES
1
• 2.5V to 6.0V Input Voltage Range
• Up to 18V Boost Converter With 4A Switch
Current
• 630kHz/1.2MHz Selectable Switching
Frequency
• Adjustable Soft-Start for the Boost Converter
• Gate Driver for External Input-to-Output
Isolation Switch
• 0.5% Accuracy Voltage Regulator for Gamma
Buffer
• Gate Voltage Shaping
• VCOM Buffer
• Reset Function (XAO Signal)
• LCD Discharge Function
• Overvoltage Protection
• Overcurrent Protection
• Thermal Shutdown
• 32-Pin 5*5mm QFN Package
APPLICATIONS
• Monitor
• TV (5V Input Voltage)
DESCRIPTION
The TPS65148 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 5 V supply rail. The device integrates a high
power step-up converter for V_S (Source Driver voltage), a very accurate voltage rail using an integrated LDO to
supply the Gamma Buffer (V_{REG_O}) and a Vcom buffer driving the LCD backplane. In addition to that, a gate
voltage shaping block is integrated. The V_GH signal (Gate Driver High voltage) supplied by an external positive
charge pump, is modulated into V_GHM with high flexibility by using a logic input VFLK and an external discharge
resistor connected to RE pin. Also, an external negative charge pump can be set using the boost converter of the
TPS65148 to generate V_GL (Gate Driver Low voltage). The integrated reset function together with the LCD
discharge function available in the TPS65148 provide the signals enabling the discharge of the LCD TFT pixels
when powering-off. The device includes safety features like overcurrent protection (OCP) and short-circuit
protection (SCP) achieved by an external input-to-output isolation switch, as well as overvoltage protection (OVP)
and thermal shutdown.
Space between text and graphic
V_IN
Boost Converter
5V
-
(Over Voltage Protection)
-
(High Voltage Stress)
V_S
13.6 V/500 mA
Gate Driver for Input-to-output
Isolation Switch
Gate Voltage
Shaping
&
LCD Discharge
Voltage Regulator for
Gamma
VCOM Buffer
(unity gain)
GD
V_GHM
24 V/20mA
V_{REG_O}
12.5 V/30 mA
V_OPO
±130mA
Reset Function
XAO
1
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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 © 2009, Texas Instruments Incorporated