Active-Semi
FEATURES
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•
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32V Input Voltage Surge
30V Steady State Input Voltage
Up to 3A Output Current
Output Voltage up to 12V
Patent Pending Active CC Sensorless Constant
Current Control
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Integrated Current Control Improves
Efficiency, Lowers Cost, and Reduces
Component Count
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Resistor Programmable Current Limit from 1.5A
to 3A
ACT4303
Rev 0, 05-Dec-11
30V/3A Sensorless CC/CV Step-Down DC/DC Converter
APPLICATIONS
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USB Chargers
LCD TV and Monitors
Digital Video Recorders
Set-Top Box
Battery Chargers
General-Purpose CC/CV Power Supplies
GENERAL DESCRIPTION
ACT4303 is a wide input voltage, high efficiency
Active CC step-down DC/DC converter that
operates in either CV (Constant Output Voltage)
mode or CC (Constant Output Current) mode.
ACT4303 provides up to 3A output current at
225kHz switching frequency.
Active CC is a patent-pending control scheme to
achieve highest accuracy sensorless constant
current control. Active CC eliminates the expensive,
high accuracy current sense resistor, making it ideal
for battery charging applications and adaptors with
accurate current limit. The ACT4303 achieves
higher efficiency than traditional constant current
switching regulators by eliminating its associated
power loss.
Protection features include cycle-by-cycle current
limit, thermal shutdown, and frequency foldback at
short circuit. The devices are available in a SOP-
8EP package and require very few external devices
for operation.
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±7.5% CC Accuracy
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Compensation of Input /Output Voltage Change
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Temperature Compensation
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Independent of inductance and Inductor DCR
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2% Feedback Voltage Accuracy
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Up to 94% Efficiency
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225kHz Switching Frequency Eases EMI Design
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Advanced Feature Set
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Integrated Soft Start
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Thermal Shutdown
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Secondary Cycle-by-Cycle Current Limit
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Protection Against Shorted ISET Pin
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SOP-8EP Package
CC/CV Curve
Input 10V~30V
HSB
IN
SW
C3
22nF
L1 30µH
6.0
ACT4303-001
5V
5.0
V
IN
= 24V
EN
ISET
FB
GND COMP
Output Voltage (V)
ACT4303
R2 52k
4.0
3.0
2.0
1.0
0.0
0
V
IN
= 12V
C1
47µF
R1
11.5k
C2
2.2nF
R3
8.2k
R4
10k
D1
SK34
C4
100µF
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
Output Current (A)
Innovative Power
TM
-1-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
