ADD8754:  LCD Panel Power, V_COM,and Gate Modulation

The ADD8754 is optimized for use in TFT LCD applications, requiring only external charge pump components to provide all the requirements for panel power, V_COM, and gate modulation. Included in a single chip are a high frequency step-up dc-to-dc switching regulator, logic voltage regulator, V_COM amplifier, and gate pulse modulation circuitry.

The step-up dc-to-dc converter provides up to 20 V output and includes a 2 A internal switch. Either a 650 kHz or 1.2 MHz step-up switching regulator frequency can be chosen, allowing easy filtering and low noise operation. It achieves 93% efficiency and features soft start to limit the inrush current at startup.

The internal voltage regulator operates with an input voltage range of 3 V to 5.5 V and delivers a load current of up to 350 mA. Three selectable output voltages are available: 2.5 V, 2.85 V, and 3.3 V.

The proprietary V_COM amplifier can deliver a peak output current of 300 mA and is specifically designed to drive TFT panel loads.

The gate pulse modulator allows shaping of the TFT gate high voltage to improve image quality. The integrated switches provide the ability to independently control the delay and slope for the gate drive voltage.

The ADD8754 is offered in a 24-lead, Pb-free LFCSP package and is specified over the industrial temperature range of −40 to +85°C.

Applications

• TFT LCD Panels for Monitors, TVs, and Notebooks