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ADM8830

Charge Pump Regulator

for Color TFT Panel

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 5.1 V 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 5 V pump doubler output.

The ADM8830 is fabricated using CMOS technology for minimal

power consumption.The part is packaged in 20-lead LFCSP

and TSSOP packages.

FEATURES

3 Output Voltages (+5.1 V, +15.3 V, –10.2 V) from

One 3 V Input Supply

Power Efficiency Optimized for Use with TFT in

Mobile Phones

Low Quiescent Current

Low Shutdown Current (<1 A)

Fast Transient Response

Shutdown Function

Power Saving during Blanking Period

Option to Use External LDO

APPLICATIONS

Handheld Instruments

TFT LCD Panels

Cellular Phones

GENERAL DESCRIPTION

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 (+5.1 V ± 2%, +15.3 V, –10.2 V) from a single

3 V input supply.These outputs are then used to provide

supplies for the LCD controller (5.1 V) and the gate drives for

the transistors in the panel (+15.3 V and –10.2 V). 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 5.1 V output.This

LDO can be shut down and an external LDO used to regulate

the 5 V doubler output and drive the input to the charge pump

section, which generates the +15.3 V and –10.2 V outputs if so

required by the user.

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

FUNCTIONAL BLOCK DIAGRAM

TIMING

GENERATOR

LDO

VOLTAGE

REGULATOR

VOLTAGE

DOUBLER

CONTROL

LOGIC

DISCHARGE

SHUTDOWN

CONTROL

C1+

C1–

VOUT

LDO IN

+5VOUT

+5VIN

C2+

C2–

C3+

C3–

+15VOUT

C4+

C4–

–10VOUT

C1

2.2F

C6

2.2F

C2

1F

C7

2.2F

+5.1V

C3

1F

+15.3V

C8

1F

C4

1F

–10.2V

C9

1F

VOLTAGE

TRIPLER

DOUBLE

TRIPLE

VOLTAGE

INVERTER

OSCILLATOR

CLKIN

SCAN/BLANK

LDO_ON/OFF

SHDN

GND

ADM8830

C5

2.2F

REV. B