Global Mixed-mode Technology Inc. G5524A Integrated Power Supply for TFT-LCD Panels with 4-Channel White LED Driver Features 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 displays (LCDs). 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 The boost converter provides the regulated supply voltage 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 0.2Ω 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 18V from an input as low as 2.8V. Soft-Start is programmed by external capacitor, which sets the input-current ramp-rate. 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 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 current. 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. 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 The low-dropout (LDO) linear regulator 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 controller 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. 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 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 input/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 reference. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.2 Feb 16, 2011 1 G5524A Global Mixed-mode Technology Inc. Ordering Information ORDER NUMBER MARKING TEMP. RANGE PACKAGE (Green) G5524ARG1U G5524AK41U 5524 5524 -40°C to 85°C -40°C to 85°C TQFN5X5-40 TQFN3.8X6.2-44 Note: RG: TQFN5X5-40 1: Bonding Code U: Tape & Reel K4: TQFN3.8X6.2-44 VGHM OPAO COMP2 AGND2 33 31 34 32 AVDD OPAI 35 CD RESET VDPM 38 36 VFLK 39 37 RE 40 1 VGH 2 30 29 ADJ AGND1 DRVP FBP AGND1 VGH 41 40 39 38 37 36 FREQ1 FB1 43 42 LDO0 44 Pin Configuration PGND 1 35 PGND LX1 2 34 VGHM VIN1 3 33 RE ISET LDOI 4 32 VFLK LED4 VDIV 5 31 VDPM 6 30 CD 7 Thermal Pad 29 RESET 8 (PGND) 28 AVDD OPAI FB1 7 (AGND) 24 PGND EN2 10 26 OPAO PWM 11 25 AGND1 VIN2 12 24 COMP2 PGND 13 23 PGND 19 20 VIN2 LX2 14 18 EN2 FREQ2 PWM 16 17 AGND1 VIN1 15 LX2 COMP1 21 14 10 SS1 LX1 13 LX2 VDIV PGND 22 12 23 9 11 8 PGND LDOI FREQ1 G5524A TQFN5X5-40 22 27 AGND2 9 21 FREQ2 ISET OVP2 20 25 19 6 LED3 AGND1 LED4 LED1 18 26 ADJ Thermal Pad 17 5 LED1 COMP1 LDOO LED2 SS1 LED2 16 LED3 27 15 28 4 LX2 3 OVP2 FBP DRVP G5524A TQFN3.8X6.2-44 Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.2 Feb 16, 2011 2