AIC1650
3-Cell, High-Efficiency, Inverting DC/DC
Converter
FEATURES
4V to 20V Input Voltage Operation.
Adjustable Output Voltage up to -40V.
Low Quiescent Current at 100µA.
Pulse Frequency Modulation Maintains High
Efficiency (max. 90%).
100KHz to 320KHz Switching Frequency.
Power-Saving Shutdown Mode (8µA Typical).
High Efficiency with Low Cost External PNP
Bipolar Transistor.
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
100µA 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.
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.
TYPICAL APPLICATION CIRCUIT
V
IN
+4V ~ 20V
100µF +
C1
VIN
VREF
SHDN
5V
FB
AIC1650
0.047µF
C4
100K
R2
R1
1M
C3
10nF
*
Sumida CD-54 SERIES
V
OUT
= -1.22V x R1/R2
CL
DHI
DLOW
GND
RB
1.5K~12K
100µF
*L
150µH
C2
+
Q1
2N2907A
D1 1N5819
V
OUT
-12V~ -40V
Negative LCD Contrast Bias Power Supply
Analog Integrations Corporation
DS-1650-02 Dec 27, 00
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
1
AIC [ ANALOG INTERGRATIONS CORPORATION ]
