AIC1628
3-Cell, High-Efficiency, Step-Up DC/DC Converter
FEATURES
4V to 24V Input Voltage Operation.
Adjustable Output Voltage.
Low Quiescent Current at 100µA.
Pulse-Skipping and Pulse-Frequency Modulation
Maintain High Efficiency (max. 95%).
90KHz to 250KHz Oscillator Frequency.
Power-Saving Shutdown Mode (8µA Typical).
Push-Pull Driver Output.
DESCRIPTION
The AIC1628 is a high performance step-up
DC/DC converter, designed to drive an external
power switch to generate programmable posi-
tive voltages. In the particularly suitable LCD
contrast bias and flash memory programming
power supply applications, typical full-load effi-
ciencies are 85% to 95%. 4V to 24V input op-
eration range allows the AIC1628 to be powered
directly by the battery pack in the 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 90KHz
to 250KHz range, small size switching compo-
nents are ideal for battery powered portable
equipments, like notebook and palmtop com-
puters.
APPLICATIONS
Flash Memory Programming Power Supply.
Positive LCD Contrast Bias for Notebook &
Palmtop Computers.
Step-Up DC/DC Converter Module.
Telecom Power Supply.
TYPICAL APPLICATION CIRCUIT
+5V ~ 24V
V
IN
*Fuse
60mΩ
VIN
0.047µF
C2
VREF
SHDN
FB
CL
DHI
DLOW
GND
AIC1628
R2
16.5K 0.033µF
C3
R1
470K 0.01µF
C4
*Buss Fuse MCR-2A
**Sumida CDR105
**L1
68µH
1N5819
D1
Q1
2SK940
C5
220µF
+36V
V
OUT
+
C1
120µF
95
V
IN
=13V
Efficiency (%)
V
IN
=9V
90
V
IN
=18V
V
IN
=5V
85
5V
+
C6
0.1µF
>50mA
V
OUT
=36V
80
0
50
100
150
200
Load Current (mA)
Color LCD Contrast Bias Supply
Efficiency vs. Output Current
Analog Integrations Corporation
DS-1628-00
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 ]
