The MAX1664 integrates power-supply and backplane drive circuitry for active-matrix thin-film-transistor (TFT) liquid crystal displays. Included are a single-output, pulse-width-modulation boost converter (0.25Ω switch), a dual-output (positive and negative) gate-driver supply using one inductor, an LCD backplane driver, and a simple phase-locked loop to synchronize all three outputs.

High switching frequency (1MHz nominal) and phase-locked operation allow the use of small, minimum-height external components while maintaining low output noise. A +2.8V to +5.5V input voltage range allows operation with any logic supply. Output voltages are adjustable to +5.5V (DC-DC 1) and to +28V and-10V (DC-DC 2). The negative output voltage can be adjusted to -20V with additional components. Also included are a logic-level shutdown and a "Ready" output (RDY) that signals when all three outputs are in regulation.

The boost-converter operating frequency can be set at 16, 24, or 32 times the backplane clock. This flexibility allows a high DC-DC converter frequency to be used with LCD backplane clock rates ranging from 20kHz to 72kHz. The MAX1664 is supplied in a 1.1mm-high TSSOP package.