SC441C Datasheet, PDF (1/1 Pages) Semtech Corporation – High Efficiency Integrated Driver for 4-Strings of 150mA LEDs

SC441C
POWER MANAGEMENT
Features
High E ciency Integrated Driver for
4-Strings of 150mA LEDs
Description
„ Wide input voltage range from 4.5V to 27V
„ 42V maximum output voltage
„ Drives up to 48 WLEDs in 4 strings
„ Programmable LED current for up to 150mA per
string
„ +/- 2% string-to-string current matching
„ Up to 90% e ciency
„ Wide 0.2% to 100% PWM dimming range
„ Possible analog dimming
„ Integrated 2.5A power switch
„ 700KHz switching frequency for small size
„ Adjustable OVP for cost-e ective output cap selection
„ Open/short LED protection
„ Thermal protection with auto-recovery
„ Thermally enhanced TSSOP-20 EDP package
„ Pb Free, Halogen Free, andWEEE/RoHS Compliant
The SC441C is a high-e ciency multiple string WLED driv-
er with an integrated boost converter. It operates over
a wide input range from 4.5V to 27V with a maximum
output voltage of 42V and a 2.5A internal power switch.
It can drive up to 48 WLEDs in 4 strings with current up
to 150mA per string. The string-to-string current match-
ing is 2% typical, 3% maximum. The overall e ciency is
greater than 90% due to the low current sense voltage
and a low-impedance internal power switch. The wide
PWM dimming range boasts a ratio of 500: 1.
The 700KHz switching frequency enables the user to op-
timize the external component sizes for e ciency. When
there are fewer than 12 LEDs in each string, users can ad-
just the output voltage protection yielding an allowable
reduction in associated costs, size and voltage ratings of
the output capacitor.
Applications
„ Medium-sized LCD panel
„ Notebook Display
„ Automotive Car Navigation Display
„ Sub-Notebook and Tablet Computer Displays
„ Portable Media Players
The SC441C also features comprehensive open and short-
circuit LED protection functions. It disables the corre-
sponding strings with LED open or LED short conditions
while maintaining normal operation of other, una ected
LED strings. This feature allows LCD panels to remain
viewable even under LED failure, wire disconnect, or
short-circuit conditions. The internal thermal shutdown
protects the IC from overheating at abnormal conditions.
The SC441C is available in a thermally-enhanced TSSOP-20
EDP package.
Typical Application Circuit
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March 04, 2010
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