SC441C
High Efficiency Integrated Driver for
4-Strings of 150mA LEDs
POWER MANAGEMENT
Features
Description
The SC441C is a high-efficiency multiple string WLED driver 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 matching is 2% typical, 3% maximum. The overall efficiency 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.
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% efficiency
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-effective 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 700KHz switching frequency enables the user to optimize the external component sizes for efficiency. When
there are fewer than 12 LEDs in each string, users can adjust the output voltage protection yielding an allowable
reduction in associated costs, size and voltage ratings of
the output capacitor.
The SC441C also features comprehensive open and shortcircuit LED protection functions. It disables the corresponding strings with LED open or LED short conditions
while maintaining normal operation of other, unaffected
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.
Applications
Medium-sized LCD panel
Notebook Display
Automotive Car Navigation Display
Sub-Notebook and Tablet Computer Displays
Portable Media Players
The SC441C is available in a thermally-enhanced TSSOP-20
EDP package.
Typical Application Circuit
9LQ99
9RXW9
9,1
6:
6:
9287
(1
6WULQJV
293,1
293,1
))/$*
3:0
293571
6&&
&203
,2
,2
,26(7
,26(7
$*1'
$*1'
,2*1'
66
('3
March 04, 2010
3*1'
3*1'
3*1'
www.semtech.com 1