Charge Pump Regulator
for Color TFT Panel
ADM8830
FEATURES
FUNCTIONAL BLOCK DIAGRAM
3 OutputVoltages (+5.1V, +15.3V, –10.2V) from
One 3V Input Supply
Power Efficiency Optimized for Use withTFT in
Mobile Phones
C5
2.2F
V
CC
C1+
VOLTAGE
DOUBLER
C1
2.2F
Low Quiescent Current
Low Shutdown Current (<1 A)
FastTransient Response
C1–
ADM8830
VOUT
LDO IN
OSCILLATOR
CLKIN
C6
2.2F
Shutdown Function
LDO
VOLTAGE
Power Saving during Blanking Period
Option to Use External LDO
REGULATOR
SCAN/BLANK
LDO_ON/OFF
+5VOUT
+5VIN
CONTROL
LOGIC
+5.1V
C7
2.2F
APPLICATIONS
C2+
DOUBLE
TRIPLE
C2
Handheld Instruments
TFT LCD Panels
Cellular Phones
C2–
C3+
C3–
1F
TIMING
GENERATOR
C3
1F
+15VOUT
+15.3V
C8
1F
VOLTAGE
TRIPLER
C4+
C4
VOLTAGE
INVERTER
C4–
1F
SHUTDOWN
CONTROL
DISCHARGE
SHDN
–10VOUT
GENERAL DESCRIPTION
–10.2V
C9
The ADM8830 is a charge pump regulator used for color thin
film transistor (TFT) liquid crystal displays (LCDs). Using
charge pump technology, the device can be used to generate three
output voltages (+5.1V ± 2%, +15.3V, –10.2V) from a single
3V input supply.These outputs are then used to provide
supplies for the LCD controller (5.1V) and the gate drives for
the transistors in the panel (+15.3V and –10.2V). Only a few
external capacitors are needed for the charge pumps. An efficient
low dropout voltage regulator also ensures that the power
efficiency is high and provides a low ripple 5.1V output.This
LDO can be shut down and an external LDO used to regulate
the 5V doubler output and drive the input to the charge pump
section, which generates the +15.3V and –10.2V outputs if so
required by the user.
GND
1F
seamlessly maintained when switching from scanning mode to
blanking mode or vice versa.
The ADM8830 has a number of power saving features, including
low power shutdown and reduced quiescent current consumption
during the blanking periods mentioned above.The 5.1V output
consumes the most power, so power efficiency is also maximized
on this output with an oscillator enabling scheme (Green Idle™).
This effectively senses the load current that is flowing and turns
on the charge pump only when charge needs to be delivered to
the 5V pump doubler output.
The ADM8830 has an internal 100 kHz oscillator for use in
scanning mode, but the part must be clocked by an external clock
source in blanking (low current) mode.The internal oscillator is
used to clock the charge pumps during scanning mode where the
current is highest. During blanking periods, the ADM8830
switches to use an external, lower frequency clock.This allows the
user to vary the frequency and maximize power efficiency during
blanking periods.The tolerances on the output voltages are
The ADM8830 is fabricated using CMOS technology for minimal
power consumption.The part is packaged in 20-lead LFCSP
andTSSOP packages.
REV.B
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