ACT4523YH-T(2011) Ver la hoja de datos (PDF) - Active-Semi, Inc

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ACT4523YH-T
(Rev.:2011)

Wide-Input Sensorless CC/CV Step-Down DC/DC Converter

Active-Semi, Inc 

Active-Semi

ACT4523

Rev 4, 21-Jul-11

Wide-Input Sensorless CC/CV Step-Down DC/DC Converter

FEATURES

• 40V Input Voltage Surge

• 38V Steady State Operation

• Up to 3A output current

• Output Voltage up to 12V

• Patent Pending Active CC Sensorless Constant

Current Control

− Integrated Current Control Improves

Efficiency, Lowers Cost, and Reduces

Component Count

• Resistor Programmable

− Current Limit from 1.5A to 3A

− Patented Cable Compensation from 0Ω to

0.3Ω

• ±7.5% CC Accuracy

− Compensation of Input /Output Voltage Change

− Temperature Compensation

− Independent of inductance and Inductor DCR

• 2% Feedback Voltage Accuracy

• Up to 94% Efficiency

• 225kHz 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-8EP Package

APPLICATIONS

• Car Charger/ Adaptor

• Rechargeable Portable Devices

• General-Purpose CC/CV Supply

GENERAL DESCRIPTION

ACT4523 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.

ACT4523 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 ACT4523 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.

Input 10V to 40V

ENABLE

HSB

IN

SW

ACT4523

EN

FB

ISET GND COMP

C3

22nF

50V

5V

L1 30µH

R2 52k

C1

47µF

R1 C2

R4

11.5k 2.2nF

10k

R3

8.2k

D1

SK34

C4

220µF

Innovative PowerTM

-1-

CC/CV Curve

6.0

VIN = 24V

5.0

4.0

VIN = 12V

3.0

2.0

1.0

0.0

0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2

Output Current (A)

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Copyright © 2011 Active-Semi, Inc.

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