G5561A

Global Mixed-mode Technology Inc. G5561A Quad-Output TFT LCD Bias DC-DC Converter Features „ 8V to 14V Input Voltage Range „ VS Output Voltage Range up to 19 V „ 1% Accurate Boost Converter with 3A Switch Current „ 1.5% Accurate 2.3A Step-Down Converter „ 500kHz/750kHz Fixed Switching Frequency „ 150mA Negative Charge Pump Driver for VGL „ 150mA Positive Charge Pump Driver for VGH „ Adjustable Sequencing for VGL, VGH „ Gate Drive Signal to Drive External MOSFET „ Internal and Adjustable Soft Start „ Cycle-by-Cycle Over Current Protection „ Short-Circuit Protection „ Overvoltage Protection „ Thermal Shutdown „ Available in TSSOP-28 Package Applications „ TFT LCD Displays General Description The G5561A DC-DC converter provides regulated voltages required by thin-film transistor (TFT) liquid crystal displays (LCD) panels in TSSOP package. One step-up converter, one step-down converter, and two charge pumps convert the 8V to 14V input voltage into four output voltages. These features complete the powersupply requirements of large screen LCD panels. The step-up converter provides source voltages VS and the step-down converter provides logic voltage for the system. The dual charge pumps independently generate adjustable regulated output voltages VGL and VGH to bias the LCD. These four blocks operate with a fixed switching frequency of 500kHz or 750kHz. Both step-up and step-down converters operate in asynchronous switch mode. Current mode control provides fast transient respons...