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Copyright © 2012 Active-Semi, Inc.

SIMPLIFIED APPLICATION CIRCUIT

ACT6357/ACT6358

High-Efficiency, 40V Step-Up WLED Bias Supplies

FEATURES

− ACT6357: 0.5A

− ACT6358: 1A

APPLICATIONS

GENERAL DESCRIPTION

The ACT6357 and ACT6358 step-up DC/DC con-

verters drive white LEDs with an externally pro-

grammable constant current. These devices feature

integrated, 40V power MOSFETs that are capable

of driving up to ten white LEDs in series, providing

inherent current matching for uniform brightness.

WLED brightness adjustment is easily achieved via

a dual-function pin, which accepts either a PWM or

an analog dimming control signal.

The ACT6357 and ACT6358 feature a variety of

protection circuits, including integrated over voltage

protection (OVP), programmable soft-start, cycle-

by-cycle current limiting, and thermal shutdown pro-

tection circuitry.

The ACT6357 has 500mA current limit, while the

ACT6358 has 1A current limit. Both parts are avail-

able in a small 3mm x 3mm 8-pin TDFN33-8.

Rev 1, 15-Nov-12