Integrated TFT Panel Power Supply

with Gate Modulation and VCOM

Preliminary Technical Data

ADD8733

Rev. PrA

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FEATURES

Step-up switching regulator with 3 A switch current limit

8 V to 16.5 V input voltage range

Adjustable output voltage up to 20 V

1.2 A series switch for power sequencing

Overvoltage protection (OVP)

Step-down switching regulator with 3 A switch current limit

8 V to 16.5 V input voltage range

Adjustable output voltage down to 2.5 V

Gate pulse modulator circuitry

Independently adjustable delay and falling slope

Positive charge-pump regulator for VGH

Negative charge-pump regulator for VGL

Two VCOM amplifiers

General

Power supply sequencing

Thermal fault protection

650 kHz or 1.2 MHz PWM frequency

Soft start

Undervoltage lockout (UVLO)

48-lead RoHS compliant LFCSP

APPLICATIONS

TFT LCD panels for TVs and monitors

BLOCK DIAGRAM

STEP-DOWN SWITCHING REGULATOR

TWO VCOM AMPLIFIERS

CONTROL

ADD8733

STEP-UP SWITCHING REGULATOR

AND POWER SEQUENCING

GATE PULSE

MODULATION

UNDERVOLTAGE

LOCKOUT AND

THERMAL PROTECTION

VGL

REGULATOR

VGH

REGULATOR

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Figure 1.

GENERAL DESCRIPTION

The ADD8733 is a 4-channel regulator with two VCOM

amplifiers and gate pulse modulation (GPM) that provides

all the necessary voltages for thin film transistor (TFT) liquid

crystal displays (LCD). Included is a step-up regulator, a step-

down regulator for digital logic, two VCOM amplifiers, two

charge-pump regulators for VGH and VGL, and an integrated

gate pulse modulator.

By offering a complete power integration solution optimized for

TFT LCD TVs and monitors, the ADD8733 helps to lower cost,

simplify board design, and increase performance over existing

solutions.

The ADD8733 is offered in a 48-lead RoHS compliant LFCSP

and is specified over the industrial temperature range of −40°C

to +85°C.