EA4501SH Datasheet, PDF (1/15 Pages) Active-Semi, Inc – 1.25A CC/CV Step-Down DC/DC Converter

ACT4501
Rev 2, 14-Nov-12
1.25A CC/CV Step-Down DC/DC Converter
FEATURES
• 10V-30V Input Voltage
• 40V Transparent Input Voltage Surge
• Up to 1.25A Constant Output Current
• Output Voltage up to 12V
• Good EMC Performance on Single Layer PCB
• Patent Pending ActiveCC Constant Current
Control
− Integrated Current Control Improves
Efficiency, Lowers Cost, and Reduces
Component Count
• Resistor Programmable Outputs
− Current Limit from 500mA to 1250mA
Patented cable compensation from DC Cable
Compensation from 0Ω to 0.5Ω
• 2% Feedback Voltage Accuracy
• Up to 90% Efficiency
• 125kHz Switching Frequency Eases EMI Design
• Advanced Feature Set
− Integrated Soft Start
− Thermal Shutdown
− Secondary Cycle-by-Cycle Current Limit
− Protection Against Shorted ISET Pin
• SOP-8 Package
APPLICATIONS
• Car Charger
• Rechargeable Portable Devices
• General-Purpose CC/CV Power Supply
GENERAL DESCRIPTION
ACT4501 is a dedicated cost-effective DC-DC
converter for 5V/1A car charger applications with a
wide input voltage and high efficiency. The
converter operates in either CV (Constant Output
Voltage) mode or CC (Constant Output Current)
mode. ACT4501 provides up to 1.25A output
current at 125kHz switching frequency.
ActiveCC is a patent-pending control scheme to
achieve high accuracy sensorless constant current
control. ActiveCC eliminates the expensive, high
accuracy current sense resistor, making it ideal for
battery charging applications and high-brightness
LED drive for architectural lighting. The ACT4501
achieves higher efficiency than traditional constant
current switching regulators by eliminating the
sense resistor and 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-8
package and require very few external devices for
operation.
Innovative Power^TM
100
90
80
70
60
50
40
1
Efficiency vs. Load Current
VIN = 12V
VIN = 16V
VIN = 24V
VOUT = 5V
10
100
1000
10000
Load Current (mA)
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Copyright © 2012 Active-Semi, Inc.