G5521 Datasheet, PDF (1/2 Pages) Global Mixed-mode Technology Inc – Integrated Multi-Channel DC-DC Converter for TFT-LCD Panels

Global Mixed-mode Technology Inc.
G5521
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
Š Fast Transient Response to Pulse Load
Š ±1% Accurate Output Voltage
Š Built-In 20V/2A, 0.2Ω N-Channel MOSFET
Š High Efficiency up to 90%
Š Programmable Soft-Start
Š Over-Current Protection
Š Output Under-Voltage Protection
„ High-Performance Operational Amplifiers
±150mA Output Short-Circuit Current
Š 12V/µs Slew Rate
Š 12MHz, -3dB Bandwidth
Š Rail-to-Rail Input and Output
„ Low Dropout Voltage Linear Regulator
Š 350mA Maximum Output Current
Š Adjustable Output Voltage
„ On-Chip GPM Controller
Š Adjustable Falling Time and Power-On Delay
Š Flicker Compensator
Š Power-On Sequence Control
„ Charge pump for VGH regulation
„ Low Voltage Detector
Š 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 G5521 includes a high-performance boost regulator, a
low dropout linear regulator (LDO), a gate pulse modulator
(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
Pin Configuration
high switching frequency (640kHz or 1.2MHz) current-
mode regulator with an integrated 20V N-Channel
0.2Ω 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
G5521R51U
5521
-40°C to 85°C
Note: R5: TQFN4X4-24
1: Bonding Code
U: Tape & Reel
PACKAGE
(Green)
TQFN4X4-24
LX 1
VIN 2
SS 3
AGND 4
ADJ 5
LDOO 6
Thermal
Pad
18 AVDD
17 DRVP
16 FBP
15 VGH
14 VGHM
13 RE
Ver: 0.9
Jul 21, 2010
G5521 TQFN4X4-24
Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.
TEL: [phone]
http://www.gmt.com.tw
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