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Global Mixed-mode Technology |
Global Mixed-mode Technology Inc.
G5524A
Integrated Power Supply for TFT-LCD Panels with
4-Channel White LED Driver
Features
2.5V to 5.5V Input Supply Range
Boost Regulator
640kHz/1.2MHz Fixed Frequency
Current-Mode Control
Fast Transient Response to Pulse Load
±1% Accurate Output Voltage
Built-In 20V/2A, 0.2Ω N-Channel MOSFET
High Efficiency up to 90%
Programmable Soft-Start
Over-Current Protection
Output Under-Voltage Protection
White-LED Driver
Wide 4.2V to 24V Input Supply Range
Adjustable Switching Frequency
40V/2A, 0.3Ω n-channel MOSFET
Input Under-Voltage Protection
Over Current Protection
Over Voltage Protection
Maximum Programmable LED Channel Current
50mA
Maximum 3% Matching between Channels
100Hz~20kHz PWM Dimming
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
Adjustable Falling Time and Power-On Delay
Flicker Compensator
Power-On Sequence Control
Charge pump for VGH regulation
Low Voltage Detector
Programmable Detecting Voltage and Delay Time
Thermal Protection
RoHs Compliant
TQFN5X5-40 and TQFN3.8X6.2-44 Package
Applications
Notebook Computer Displays
UMPCs
LCD Monitor
General Description
The G5524A includes a high-performance boost regulator,
4-channel LED driver, 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 active-matrix thin-film transistor (TFT) liquid-crystal dis-
plays (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) cur-
rent-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 LED driver automatically regulated supply voltage for
the LED light bars without the need to calculate the output
for different LED types. A FREQ2 pin is applied to adjust
switching frequency in the range of 640kHz to 2MHz. It
also integrates a 40V n-channel MOSFET that provides
high output power. The 4-channel current driver is ideal
for constant current driving, and, well matched less than
3%. To set the maximum driving current, the ISET pin is
used to determine reference current. Each channel of the
current drivers is set to 1300 times of this reference cur-
rent. A PWM pin can be used to perform PWM dimming
from the range of 100Hz to 20kHz. Open LED-string
automatically disable the channel from entering over
voltage protection.
The low-dropout (LDO) linear regulator can supply up to
350mA current while input voltage is 3.3V. It uses an inter-
nal 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
detecting level is decided by an external resistor divider
and the delay time is programmable by an external ca-
pacitor.
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.
Ver: 0.2
Feb 16, 2011
TEL: 886-3-5788833
http://www.gmt.com.tw
1
Global Mixed-mode Technology Inc.
Ordering Information
ORDER
NUMBER
G5524ARG1U
G5524AK41U
Note: RG: TQFN5X5-40
1: Bonding Code
U: Tape & Reel
MARKING
5524
5524
K4: TQFN3.8X6.2-44
TEMP.
RANGE
-40°C to 85°C
-40°C to 85°C
Pin Configuration
G5524A
PACKAGE
(Green)
TQFN5X5-40
TQFN3.8X6.2-44
VGHM 1
VGH 2
FBP 3
DRVP 4
LDOO 5
ADJ 6
FB1 7
FREQ1 8
PGND 9
LX1 10
Thermal
Pad
(AGND)
30 ISET
29 LED4
28 LED3
27 LED2
26 LED1
25 OVP2
24 PGND
23 PGND
22 LX2
21 LX2
PGND 1
LX1 2
VIN1 3
LDOI 4
VDIV 5
SS1 6
COMP1 7
AGND1
FREQ2
8
9
EN2 10
PWM 11
VIN2 12
PGND 13
Thermal
Pad
(PGND)
35 PGND
34 VGHM
33 RE
32 VFLK
31 VDPM
30 CD
29 RESET
28 AVDD
27 OPAI
26 OPAO
25 AGND1
24 COMP2
23 PGND
G5524A TQFN5X5-40
G5524A TQFN3.8X6.2-44
Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.
Ver: 0.2
Feb 16, 2011
TEL: 886-3-5788833
http://www.gmt.com.tw
2
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