TFT-LCD DC-DC Converter with Operational Amplifiers
TFT LCD, DC-DC Converter with a High-Performance Step-Up Regulator, Two Linear-Regulator Controllers, and High-Current Operational Amplifiers for Active-Matrix, Thin-Film Transistor (TFT) LCDs
The MAX8795A includes a high-performance step-up
regulator, two linear-regulator controllers, and five high-current
operational amplifiers for active-matrix, thin-film
transistor (TFT), liquid-crystal displays (LCDs). Also
included is a logic-controlled, high-voltage switch with
adjustable delay.
The step-up DC-DC converter provides the regulated
supply voltage for the panel source driver ICs. The converter
is a high-frequency (1.2MHz) current-mode regulator
with an integrated 20V n-channel MOSFET that
allows the use of ultra-small inductors and ceramic
capacitors. It provides fast transient response to pulsed
loads while achieving efficiencies over 85%.
The gate-on and gate-off linear-regulator controllers
provide regulated TFT gate-on and gate-off supplies
using external charge pumps attached to the switching
node. The MAX8795A includes five high-performance
operational amplifiers. These amplifiers are designed to
drive the LCD backplane (VCOM) and/or the gamma-correction
divider string. The device features high output
current (±130mA), fast slew rate (45V/µs), wide
bandwidth (20MHz), and rail-to-rail inputs and outputs.
The MAX8795A is available in a lead-free, 32-pin, thin
QFN package with a maximum thickness of 0.8mm for
ultra-thin LCD panels, as well as in a 32-pin LQFP
package with 0.8mm pin pitch.