ACT6357/ACT6358
Rev PrB, 30-Aug-07
Advanced Product Information – All Information Subject to Change
High-Efficiency, 40V Step-Up WLED Bias Supplies
FEATURES
High-Efficiency DC/DC WLED Bias Supply
Internal 40V, 0.55Ω Power MOSFET
Up to 10 WLEDs per String
Two Peak Current Options:
ACT6357: 0.5A
ACT6358: 1A
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.
Supports Analog and PWM LED Dimming
Integrated Over-Voltage Protection (OVP)
Programmable Soft-Start Function
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Tiny TDFN33-8 Package
APPLICATIONS
TFT LCD Displays
Smart Phones
Portable Media Players
GPS/Personal Navigation Devices
SIMPLIFIED APPLICATION CIRCUIT
Up to
10 WLEDs
V
IN
2.6V to 5.5V
IN
SW
V
OUT
Enable
Brightness Control
EN
BC
SS
ACT6357
ACT6358
OV
FB
G
Innovative Products.
Active Solutions.
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Copyright © 2007 Active-Semi, Inc.