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