G2511 Datasheet, PDF (1/2 Pages) Global Mixed-mode Technology Inc – Power Supply for TFT-LCD Panels with 6-Channel White LED Driver

Global Mixed-mode Technology
G2511
Integrated Power Supply for TFT-LCD Panels with
6-Channel White LED Driver
Features
„ 2.5V to 5.5V Input Supply Range
„ Boost Regulator
Š 1.2MHz Fixed Frequency
Š Current-Mode Control
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
„ White-LED Driver
Š Wide 4.2V to 24V Input Supply Range
Š 1.2MHz Fixed Frequency
Š High Efficiency up to 90%
Š 40V/2A, 0.2Ω n-channel MOSFET
Š Input Under-Voltage Protection
Š Over Current Protection
Š Over Voltage Protection
Š Maximum Programmable LED Channel Current
30mA
Š Current accuracy ±3% and current balance ±2%
Š 100Hz~25kHz PWM Dimming
Š Mixed mode and PWM Dimming method
„ High-Performance Operational Amplifiers
Š ±200mA 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 Flicker Compensator
Š Power-On Sequence Control
„ Linear Regulator Controller for VGL
„ Low Voltage Detector
Š Programmable Detecting Voltage and Delay Time
„ Thermal Protection
„ RoHs Compliant
„ TQFN5X5-40 Package
The boost converter provides the regulated supply volt-
age for the panel source driver ICs. The converter is a
high switching frequency (1.2MHz) current-mode regula-
tor with an integrated 20V N-Channel 0.2Ω MOSFET
that allows the use of ultra-small inductors and ceramic
capacitors. It provides fast transient response to pulsed
loading while achieving efficiency over 90%. The device
can produce output voltage as high as 15V from an input
as low as 2.8V. Soft-Start is programmed by external
capacitor, which sets the input-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. It also integrates a 40V n-channel
MOSFET that provides high output power. The 6-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 cur-
rent. Each channel of the current drivers is set to 800
times of this reference current. A PWM pin can be used
to perform PWM dimming from the range of 100Hz to
25kHz.
The MODE pin in G2511 is used to set the dimming
mode. If MODE pin set to VCC or floating, the dimming
mode is in the PWM mode, the current driver ON/OFF is
synchronized with the PWMB signal. If Mode pin set to
GND, PWMB and ILED current is set at PWMB duty mul-
tiplied by ISET current when PWMB duty ≥ 25%. If the
PWMB duty <25%, the ILED current is fixed at 0.25xISET,
and the dimming duty is 4 x PWMB duty. Open
LED-string automatically disable the channel from enter-
ing 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 by the internal timer (60ms) while
power-on for achieving a corrected power-on sequence for
gate driver ICs. The falling time of the Gate-On voltage is
programmable by external capacitor and resistor.
Applications
„ Notebook Computer Displays
„ UMPCs
„ LCD Monitor
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.
General Description
The G2511 includes a high-performance boost regulator,
6-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 VGL linear regulator for ac-
tive-matrix thin-film transistor (TFT) liquid-crystal displays
(LCDs).
The VCOM buffer can drive the LCD VCOM voltage that
features high short-circuit current (200mA), fast slew rate
(12V/µs), wide bandwidth (12MHz) and rail-to-rail in-
put/output.
The gate-off linear regulator controller provides regulated
TFT gate-off supplies using external charge pump at-
tached to the switching node. Using the gate-low regula-
tor after the produced negative voltage can regulate the
exceeded voltage.
Ver: 0.1
Oct 25, 2013
TEL: [phone]
http://www.gmt.com.tw
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