AIC1650

3-Cell, High-Efficiency, Inverting DC/DC

Converter

Analog Integrations Corporation

4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC

www.analog.com.tw

DS-1650-02 Dec 27, 00

TEL: 886-3-5772500

FAX: 886-3-5772510

1

FEATURES

4V to 20V Input Voltage Operation.

Adjustable Output Voltage up to -40V.

Low Quiescent Current at 100

µA.

Pulse Frequency Modulation Maintains High

Efficiency (max. 90%).

100KHz to 320KHz Switching Frequency.

Power-Saving Shutdown Mode (8

µA Typical).

High Efficiency with Low Cost External PNP

Bipolar Transistor.

APPLICATIONS

Negative LCD Contrast Bias for

1. Notebook & Palmtop Computers.

2. Pen-Based Data System.

3. Portable Data Collection Terminals.

4. Personal Digital Assistants.

Negative Voltage Supply.

DESCRIPTION

The AIC1650 is a high performance inverting

DC/DC converter, designed to drive an external

power switch to generate programmable nega-

tive voltages. In the particularly suitable LCD

bias contrast application, maximum efficiency of

90% can be achieved with low cost PNP bipolar

transistor drivers. 4V to 20V input operation

range allows the AIC1650 to be powered di-

rectly by the battery pack in most battery-

operated applications for greater efficiency.

Output voltage can be scaled to -40V or greater

by two external resistors. A pulse frequency

modulation scheme is employed to maintain

high efficiency conversion under wide input

voltage range. Quiescent current is

about

100

µA and can be reduced to 8µA in shutdown

mode. Switching frequency being around

100KHz to 320KHz range, small size switching

components are ideal for battery powered port-

able equipments, like notebook and palmtop

computers.

TYPICAL APPLICATION CIRCUIT

D1 1N5819

AIC1650

CL

DHI

DLOW

FB

GND

SHDN

VIN

VREF

C3

10nF

C4

0.047

µF

*L

150

µH

Q1

2N2907A

RB

1.5K~12K

R1

1M

C2

C1

+4V ~ 20V

-12V~ -40V

5V

100

µF

*

Sumida CD-54 SERIES

+

+

R2

100K

Negative LCD Contrast Bias Power Supply