The LT ®1943 is a highly integrated, 4-output regulator designed to power large TFT LCD panels. It employs switching regulators—instead of linear regulators—to minimize power dissipation and accommodate a wide input voltage range. The wide input range, 4.5V to 22V, allows it to accept a variety of power sources, including the commonly used 5V, 12V and 19V AC adapters. The first buck regulator provides a logic voltage with up to 2A of current. The other three switching regulators provide the three bias voltages, AVDD, VON and VOFF, required by LCDs. All four regulators are synchronized to a 1.2MHz internal clock, allowing the use of small, low cost inductors and ceramic capacitors. Since different types of panels may require different bias voltages, all output voltages are adjustable for maximum flexibility. Programmable soft-start capability is included in all outputs to limit inrush current. The LT1943 has a built-in start-up sequence and panel protection feature. The LT1943 is available in a low-profile 28-pin TSSOP package.
This document is Design Note 349 from Linear Technology Corporation, focusing on the LT1943 quad output switching converter. The device is engineered to provide power for large TFT LCD panels by employing four switching regulators instead of linear ones, which minimizes power dissipation and accommodates a wide input voltage range of 4.5V to 22V.
The note details the internal architecture where one buck regulator provides logic voltage up to 2A, while three other switching regulators generate adjustable bias voltages (AVpp, Von, Vorr) required by LCDs. It includes information on synchronized operation at a 1.2MHz clock, programmable soft-start capabilities, and panel protection features.
The LT1943 is a highly integrated, 4-output regulator designed to power large TFT LCD panels.
The device accepts a wide input voltage range of 4.5V to 22V.
The first buck regulator provides a logic voltage with up to 2A of current.