The RT9921 includes a high-performance boost regulator,
a low dropout linear regulator (LDO), a gate pulse
modulator (GPM), a voltage detector, a VCOM buffer (unitygain
OPA), and a VGH charge pump controller for activematrix
thin-film transistor (TFT) liquid-crystal displays
(LCDs).
The boost converter provides the regulated supply voltage
for the panel source driver ICs. The converter is a high
switching frequency (640kHz or 1.2MHz) current-mode
regulator with an integrated 16V N-Channel 0.2Ω MOSFET
that allows the use of ultra-small inductors and ceramic
capacitors. It provides fast transient response to pulsed
loading while achieving efficiency over 90%. The device
can produce output voltage as high as 15V from an input
as low as 2.5V. Soft-Start is programmed by external
capacitor, which sets the input-current ramp-rate.
The low-dropout (LDO) linear regulator can supply up to
350mA current while input voltage is 3.3V. It uses an
internal P-MOSFET as the pass device. It is suitable for
the supply voltage of the timing controller.资料下载
