Dallas - Texas Instruments has two new triple-output charge pumps and a switch-mode dc/dc source for maximizing power efficiency in liquid crystal displays for notebooks.
The TPS65110 and TPS65111 triple-output charge pumps manage the three bias voltages required in most low-temperature polysilicon LCDs used in personal digital assistants, smart phones and digital cameras. The TPS65110 provides 3.3, 7.5, and -2.7 volts; the TPS65111 delivers 5, 9, and -3 V. The devices feature internally set power-up and power-down sequencing and require only the addition of a few ceramic capacitors.
The company's new power supply IC, the inductive switch-mode TPS65100, manages all the voltages required by a thin-film-transistor (TFT) LCD display, including appropriate soft-start, internal power-on sequencing, and fault protection and thermal shutdown circuitry. Using a 1.5-MHz boost converter, it delivers up to 15 V (LCD main source drive) at 350 mA from a 2.7- to 5.5-V input.
An integrated adjustable charge pump provides the LCD (positive) gate drive voltage, with a second adjustable pump providing a negative gate drive voltage. For LCD panels powered from a 5-V source, the TPS65100 provides an auxiliary linear controller to deliver a regulated 3.3 V for logic circuitry. In addition, the IC integrates the Vcom buffer to drive the display backplane.
The TPS65110 and TPS65111, in a 4 by 4-mm QFN, sell for $1.69 each in 1k quantities; the TPS65100, in a 4 by 4-mm QFN or 24-pin TSSOP, is priced at $2.69 each, also in 1k quantities. Evaluation modules are available.
Call (800) 477-8924