Ver: 0.2

Nov 22, 2011

TEL: 886-3-5788833

http://www.gmt.com.tw

1

G5521A

Global Mixed-mode Technology

Integrated Multi-Channel DC-DC Converter for TFT-LCD Panels

Features

2.5V to 5.5V Input Supply Range

640kHz/1.2MHz Current-Mode Boost Regulator

Fast Transient Response to Pulse Load

±1% Accurate Output Voltage

Built-In 20V/2A, 0.2

Ω N-Channel MOSFET

High Efficiency up to 90%

Programmable Soft-Start

Over-Current Protection

Output Under-Voltage Protection

High-Performance Operational Amplifiers

±150mA Output Short-Circuit Current

12V/µs Slew Rate

12MHz, -3dB Bandwidth

Rail-to-Rail Input and Output

Low Dropout Voltage Linear Regulator

350mA Maximum Output Current

Adjustable Output Voltage

On-Chip GPM Controller

Flicker Compensator

Power-On Sequence Control

Charge pump for VGH regulation

Low Voltage Detector

Programmable Detecting Voltage and Delay Time

Thermal-Overload Protection

RoHs Compliant

TQFN4X4-24 Package

Applications

LCD Monitor

Notebook Computer Displays

LCD TVs

General Description

The G5521A includes a high-performance boost regulator,

a low dropout linear regulator (LDO), a gate pulse modula-

tor (GPM), a voltage detector, a VCOM buffer (unity-gain

OPA), and a VGH charge pump controller for activematrix

thin-film transistor (TFT) liquid-crystal displays (LCDs).

The boost converter provides the regulated supply volt-

age for the panel source driver ICs. The converter is a

high switching frequency (640kHz or 1.2MHz) current-

mode regulator with an integrated 20V N-Channel

0.2

Ω MOSFET that allows the use of ultra-small inductors

and ceramic capacitors. It provides fast transient re-

sponse to pulsed loading while achieving efficiency over

90%. The device can produce output voltage as high as

18V from an input as low as 2.8V. Soft-Start is pro-

grammed by external capacitor, which sets the in-

put-current ramp-rate. The low-dropout (LDO) linear regu-

lator can supply up to 350mA current while input voltage is

3.3V. It uses an internal PMOS as the pass device. It is

suitable for the supply voltage of the timing controller.

The GPM is controlled by frame signals from timing con-

troller to modulate the Gate-On voltage, VGHM, which acts

a flicker compensation circuit to reduce the coupling effect

between gate lines and pixels. It also can delay the

Gate-On voltage while power-on for achieving a corrected

power-on sequence for gate driver ICs. Both of power-on

delay time and the falling time of the Gate-On voltage are

programmable by external capacitor and resistor.

The voltage detector monitors the supply voltage to issue a

reset signal while the detected voltage is too low. The de-

tecting level is decided by an external resistor divider and

the delay time is programmable by an external capacitor.

The VCOM buffer can drive the LCD VCOM voltage that

features high short-circuit current (150mA), fast slew rate

(12V/µs), wide bandwidth (12MHz) and rail-to-rail in-

put/output.

The VGH charge pump controller provides regulated TFT

Gate-On voltage. The regulation of the positive charge

pump is generated by the internal comparator that senses

the output voltage and compares it with an internal refer-

ence.

Ordering Information

ORDER

NUMBER

MARKING

TEMP.

RANGE

PACKAGE

(Green)

G5521AR51U

5521

-40°C to 85°C

TQFN4X4-24

Note: R5: TQFN4X4-24

1: Bonding Code

U: Tape & Reel

Pin Configuration

G5521A TQFN4X4-24

LX

VIN

SS

AGND

ADJ

LDOO

AVDD

DRVP

FBP

VGH

VGHM

RE

1

2

3

4

5

6

13

14

15

16

17

18

Thermal

Pad

Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.

G5521A TQFN4X4-24

LX

VIN

SS

AGND

ADJ

LDOO

AVDD

DRVP

FBP

VGH

VGHM

RE

1

2

3

4

5

6

13

14

15

16

17

18

Thermal

Pad

Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.