ADM8839ACP(RevA) 데이터 시트보기 (PDF) - Analog Devices

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ADM8839ACP
(Rev.:RevA)

Charge Pump Regulator for Color TFT Panels

Analog Devices 

FEATURES

3 Voltages (+5 V, +15 V, –15 V) from

a Single 3 V Supply

Power Efficiency Optimized for Use

with TFT in Mobile Phones

Low Quiescent Current

Low Shutdown Current (<5 ␮A)

Shutdown Function

Option to Use External LDO

APPLICATIONS

Hand-held Instruments

TFT LCD Panels

Cellular Phones

Charge Pump Regulator

for Color TFT Panels

ADM8839

FUNCTIONAL BLOCK DIAGRAM

ADM8839

OSCILLATOR

LDO_ON/OFF

CONTROL

LOGIC

TIMING

GENERATOR

SHDN SHUTDOWN

CONTROL

C5, 2.2␮F

VCC

VOLTAGE

DOUBLER

LDO

VOLTAGE

REGULATOR

DOUBLE

VOLTAGE

TRIPLER

TRIPLE

DISCHARGE

VOLTAGE

INVERTER

GND

C1+

C1, 2.2␮F

C1–

VOUT

LDO_IN

C6, 2.2␮F

+5VOUT

+5VIN

C2+

+5V

C7, 2.2␮F

C2, 0.22␮F

C2–

C3+

C3– C3, 0.22␮F

+15VOUT

+15V

C4+

C8, 0.22␮F

C4– C4, 0.22␮F

–15VOUT

–15V

C9, 0.22␮F

GENERAL DESCRIPTION

The ADM8839 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

voltages (+5 V ± 2%, +15 V, –15 V) from a single 3 V supply.

These voltages are then used to provide supplies for the LCD

controller (5 V) and the gate drives for the transistors in the

panel (+15 V and –15 V). Only a few external capacitors are

needed for the charge pumps. An efficient low dropout (LDO)

voltage regulator ensures that the power efficiency is high and

provides a low ripple 5 V output. This LDO can be shut down

and an external LDO can be used to regulate the 5 V doubler

output and drive the input to the charge pump section that

generates the +15 V and –15 V outputs, if required by the user.

The ADM8839 has a power save shutdown feature. The 5 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 ADM8839 is fabricated using CMOS technology for minimal

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

(lead frame chip scale package).

REV. A

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties that

may result from its use. No license is granted by implication or otherwise

under any patent or patent rights of Analog Devices. Trademarks and

registered trademarks are the property of their respective companies.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

www.analog.com

Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved.

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