The MAX17014 multiple-output power-supply controller
generates all the supply rails for thin-film transistor
(TFT) liquid-crystal display (LCD) panels in TVs and
monitors operating from a regulated 12V input. It
includes a step-down and a step-up regulator, a positive
and a negative charge pump, two operational
amplifiers, and a Dual Mode™ logic-controlled high-voltage
switch control block. The MAX17014 can operate
from 8V to 16.5V input voltages and is optimized for
LCD TV panel and LCD monitor applications running
directly from 12V supplies.
The step-up and step-down regulators feature internal
power MOSFETs and high-frequency operation allowing
the use of small inductors and capacitors, resulting
in a compact solution. Both switching regulators use
fixed-frequency current-mode control architectures,
providing fast load-transient response and easy compensation.
A current-limit function for internal switches
and output-fault shutdown protect the step-up and
step-down power supplies against fault conditions. The
MAX17014 provides soft-start functions to limit inrush
current during startup. The MAX17014 provides
adjustable power-up timing.
The positive and negative charge-pump regulators provide
TFT gate driver supply voltages. Both output voltages
can be adjusted with external resistive
voltage-dividers. The switch control block allows the
manipulation of the positive TFT gate driver voltage.
The MAX17014 includes two high-current operational
amplifiers designed to drive the LCD backplane
(VCOM). The amplifier features high output current
(±150mA), fast slew rate (100V/µs), wide bandwidth
(20MHz), and rail-to-rail inputs and outputs. A series
p-channel MOSFET is integrated to sequence power to
AVDD after the MAX17014 has proceeded through
normal startup, and provides True Shutdown™.
The MAX17014 is available in a small (7mm x 7mm),
low-profile (0.8mm), 48-pin thin QFN package and
operates over a -40°C to +85°C temperature range.
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