TPS65121

The TPS6512x DC-DC converter supplies all three voltages required by amorphous-silicon (a-Si) and low-temperature poly-silicon (LTPS) TFT-LCD displays. The compact layout of the TPS6512x uses a single inductor to generate independently-regulated positive and negative outputs. A free-running variable peak current PWM control scheme time-multiplexes the inductor between outputs. This control architecture TPS6512x operates at a pseudo-fixed-frequency to provide fast response to line and load transients while maintaining a relatively constant switching frequency and high efficiency over a wide range of input and output voltages. Due to the high switching frequency capability of the device, inexpensive and ultra-thin 8.2 or 10 µ H inductors can be used.

The main output, V MAIN , is post-regulated to provide a low-ripple source drive voltage for the LCD display. The auxiliary outputs generate a boosted output voltage, V GH , up to 20 V, and a negative output voltage, V GL , down to -18 V for the LCD gate drive. The TPS6512x has internal current limiting for high reliability under fault conditions. Additionally, the TPS6512x offers a fixed output linear regulator for the LCD logic circuitry.