AIC1578 Datasheet, PDF (1/7 Pages) Analog Intergrations Corporation – High-Efficiency, Step-Down DC/DC Converter

AIC1578
High-Efficiency, Step-Down DC/DC Converter
FEATURES
• 4V to 20V Input Voltage Operation.
• High Efficiency (up to 95%).
• Low Quiescent Current at 90µA.
• Pulse-Skipping and Pulse-Frequency Modulation.
• Inputs-Uncommitted Current Sense Comparator.
• Duty Cycle Adjustable.
• 90KHz to 280KHz Oscillator Frequency.
• Power-Saving Shutdown Mode (8µA Typical).
• Push-Pull Driver Output.
APPLICATIONS
• Notebook 5V/3.3V Main Power
• Step-Down DC/DC Converter Module.
• Constant Current Source for Battery Chargers.
TYPICAL APPLICATION CIRCUIT
VIN
IRF9Z34
Q1
* L1
33µH
D1
1N5820
C3 ⁺
220µF
**RS
+
C4
D2
+
C1
C2
RDUTY
R2 ^1M
VIN
DUTY
CS+
CS -
1M
SHDN
DRI
Control
FB
GND
AIC1578
*Sumida MPP CORE **Charge current=57mV/RS
Constant Current Source for Battery Charger
DESCRIPTION
The AIC1578 is a high performance step-down
DC/DC converter, designed to drive an external
P-channel MOSFET to generate programmable
output voltages. Two main schemes of Pulse-
Skipping and Pulse-Frequency Modulation are
employed to maintain low quiescent current and
high conversion efficiency under wide ranges of
input voltage and loading condition. The
AIC1578 delivers 10mA to 2A of output current
with 87%~93% efficiency at V_IN=9V, V_OUT=5V
condition. A current sense comparator with both
inverting and non-inverting input uncommitted is
included to provide the crucial function of either
current limit protection or constant output current
control. When the AIC1578 is used in a high-side
current sensing step-down constant current
source, the efficiency is typically greater than
90%. Duty cycle can be adjusted to greater than
90% by connecting a resistor from DUTY pin to
V_IN. Quiescent current is about 90µA and can be
reduced to 8µA in shutdown mode. Switching
frequency being in around 90KHz to 280KHz
range, small size switching components are ideal
for battery powered portable equipment.
ORDERING INFORMATION
AIC1578 XX
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
TEMPERATURE RANGE
C: 0°C~+70°C
ORDER NUMBER
AIC1578CN
(PLASTIC DIP)
AIC1578CS
(PLASTIC SO)
PIN CONFIGURATION
TOP VIEW
VIN 1
DUTY 2
SHDN ³
FB 4
8 CS+
7 CS-
6 DRI
5 GND
Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
DS-1578-02 Dec 27, 00
TEL: [phone] FAX: [phone]
www.analog.com.tw
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