TFT-LCD Power-Supply Controllers

The MAX1513/MAX1514 provide complete power-supply solutions for active-matrix thin-film transistor (TFT) liquid-crystal displays (LCDs). Both devices include a high-performance step-up regulator controller, three linear- regulator controllers, and an adjustable delay block for startup sequencing. The MAX1513 includes an additional linear-regulator controller and a high-performance buffer amplifier. The MAX1513/MAX1514 can operate from 2.7V to 5.5V input supplies and provide overload protection with timer delay latch on all the regulated outputs.

The step-up regulator controller drives an external N-channel MOSFET to generate the regulated supply voltage for the panel source-driver ICs. Its current-mode control architecture provides fast transient response to pulsed loads. The high switching frequency (up to 1.5MHz) allows the use of ultra-small inductors and ceramic capacitors while achieving efficiencies over 85% using lossless current sensing. The internal soft-start limits the input surge current during startup.

The gate-on and gate-off linear-regulator controllers of the MAX1513/MAX1514 provide regulated TFT gate-on and gate-off supplies. The gate-on supply is activated after an adjustable delay following the step-up regulator. The logic linear-regulator controller can be used to create a low-voltage logic supply. The gamma linear-regulator controller of the MAX1513 can be used to generate a gamma-correction reference supply or another generalpurpose supply rail. The MAX1513's high-performance buffer amplifier can drive the LCD backplane (VCOM) or the gamma-correction divider string.

The MAX1513/MAX1514 are available in 4mm x 4mm 20-pin thin QFN packages with a maximum thickness of 0.8mm, suitable for ultra-thin LCD panel design.

Applications

* Automotive Displays * LCD Monitors and TVs * Notebook Computer Displays

* 2.7V to 5.5V Input Supply Range

* Input-Supply Undervoltage Lockout

* Current-Mode Step-Up Controller

* Fast Transient Response to Pulsed Load

* High Efficiency

* Lossless Current Sensing

* 430kHz/750kHz/1.5MHz Switching Frequency

* Linear-Regulator Controllers for VGON, VGOFF

* Linear-Regulator Controller for Logic Supply

* High-Performance Buffer Amplifier (MAX1513 Only)

* Additional Linear-Regulator Controller (MAX1513 Only)

* Power-Up Sequence and VGON Delay Control

* VMAIN, VGON, VGOFF, VGAMMA Shutdown Control

* Timer-Delay Fault Latch for All Outputs

* Thermal-Overload Protection