AnalogicTech delivers integrated power solution for small backlit LCDs

Santa Clara, Calif. — Advanced Analogic Technologies, Inc. (AnalogicTech) has introduced the AAT282X active-matrix thin-film transistor (TFT) liquid crystal display (LCD) dc/dc converter family that includes a WLED driver and VCOM buffer, delivering a fully integrated power solution for portable backlit displays ranging from 5 to 10 inches. Key target applications include automotive displays, digital photo frames, netbooks, e-readers and handheld GPS navigation devices.

Part of AnalogicTech’s integrated Panel Power solutions family, the AAT282X uses internal, low power, positive and negative charge pumps for higher efficiencies, lower ripples and tighter regulations to generate 30-V symmetrical VGH and VGL voltages. With operation down to 2.5 V, the AAT282X boost converter architecture is suitable for a wide range of portable backlit display devices.
The AAT2822 flagship device includes a triple-output dc/dc converter for powering the column and row gate drivers, a 28-V WLED backlight driver, and a VCOM buffer for distributing the mid-scale reference voltage across the display. Depending on the display requirements, the AAT282X family offers additional affordable solutions that remove features such as the VCOM buffer and backlight options, offering design flexibility to accommodate any unique features required by a specific display design, said AnalogicTech.

All products in the AAT282X family are offered in a 4 x 4-mm Pb-free TQFN package. The complete solution fits in a 30 x 21-mm footprint when incorporating the optional evaluation board.

Here are key features of the new product family.

LCD bias power:
— 2.5-V to 5.5-V Input Supply Range
— 1.3MHz Fixed Frequency Current-Mode
— Step-Up Regulator
— Fast Transient Response
— Adjustable Voltage up to 14.5V (+/-1% Typical Accuracy)
— Small External Inductor and Capacitors
— Integrated Soft Start and Sequencing of all Rails
— Short-Circuit, Over-Voltage, and Over-Temperature Protection

Charge pump outputs: VGH & VGL
— Up to 13.2V Input Supply (VDD)
— Adjustable Voltage up to +/-30V@ 20mA (+/-3% Typical Accuracy)

WLED Driver:
— Input Voltage Range: 2.5V to 25V
— Maximum Continuous Output: 12V @ 260mA & 28V @ 50mA
— Panel sizes from 5″ to 10″
— Constant LED Current with 6% Accuracy
— PWM Dimming Control Up to 1kHz with a High Frequency Filtered PWM
— 1.3MHz Switching Fixed Frequency
— Up to 90% Efficiency

VCOM buffer:
— 13 V/us Slew Rate
— 12MHz, -3dB Bandwidth
— +/-75mA Output Short-Circuit Current
— Low 1.5-mA Quiescent Current

Availability: The AAT282X family is made up of four separate products: the AAT2822; AAT2823; AAT2824; and AAT2825. The AAT2822 and AAT2823 are available immediately while the AAT2824 and AAT2825 are available on request. To order samples, visit