TFT LCD DC-DC Converter with Integrated Charge Pumps

The MAX8753 quadruple-output DC-DC converter provides the regulated voltages required by active-matrix, thin-film transistor (TFT), liquid-crystal displays (LCDs). It includes a high-power step-up regulator (VMAIN), two low-power charge pumps (VPOS and VNEG), and a low-voltage 300mA linear regulator (VLOGIC).

The step-up DC-DC converter is a high-frequency (1MHz) current-mode regulator with a built-in power MOSFET that allows the use of ultra-small inductors and ceramic capacitors. It provides fast transient response to pulsed loads and includes an automatic pulse-skipping mode that increases efficiency over a wide-load current range. The 1.5A current limit allows a +10V output at more than 300mA from a +3.3V input.

The two charge pumps independently regulate one positive and one negative output voltage. The positive charge pump is a voltage tripler that accepts an input voltage up to +13V and delivers a 20mA output up to +28V without external switches or diodes. The negative charge pump inverts an input voltage up to +24V and delivers a 20mA negative output using external diodes.

The logic linear regulator converts the IC's +2.6V-to-+5.5V input to a regulated +2.5V or adjustable output. The MAX8753 is available in a 28-pin thin QFN package with a maximum thickness of 0.8mm for ultra-thin LCD panel design.

Applications

* Car-Navigation Displays * LCD Monitors * Notebook Computers, PDAs