Innovative Power

TM

- 1 -

www.active-semi.com

Copyright © 2013 Active-Semi, Inc.

FEATURES

Current Control

Efficiency, Lowers Cost, and Reduces

Component Count

0.3Ω

APPLICATIONS

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.

ACT4523

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

Rev 7, 01-Aug-13

Output Current (A)

0

0.4

0.8

1.2

1.6

2.0

2.4

2.8

3.2

6.0

5.0

4.0

3.0

2.0

1.0

0.0

CC/CV Curve

ACT4523

HSB

IN

EN

COMP

FB

SW

ISET

ENABLE

Input 10V to 40V

5V

GND

C1

47µF

R1

11.5k

C2

2.2nF

R3

8.2k

R4

10k

D1

SK34

R2 52k

C4

220µF

C3

22nF

50V

L1 30µH