SC4541 Datasheet, PDF (1/19 Pages) Semtech Corporation – High Frequency LED Driver with Integrated Schottky and Simple Interconnect

SC4541
High Frequency LED Driver with
POWER MANAGEMENT
Features
Integrated Schottky and Simple Interconnect
Description
„„ V_IN Range — 2.9V to 22V
„„ V_OUT Range — Up to 25V
„„ I_OUT Range:
„„ Up to 100mA (Boost)
„„ Up to 200mA (Buck)
„„ Drives Up to 7 Series WLEDs (Boost)
„„ Drives Up to 5 Series WLEDs (Buck)
„„ Integrated Schottky Rectifier
„„ Single-Wire LED Connect
„„ Current Mode Control
„„ Frequency — 2.0MHz
„„ No External Compensation
„„ Direct PWM Dimming
„„ 100:1 Range at 500Hz
„„ Open-LED Protection — 27V
„„ Low Shutdown Current < 1µA
„„ Package Options:
„„ Low Profile MLPD-UT, 6-pin 2x2 x0.6(mm)
„„ SOT23, 6-pin 2.9x2.8 x1.45(mm)
„„ Lead-free, Halogen-Free and WeEE/RoHS Compliant
Applications
„„ Keypad Illumination
„„ DSC and DSLR Display Backlight
„„ Cellular Handsets
„„ Automotive Lighting
The SC4541 is a fully integrated, high voltage boost (step-
up) and buck (step-down) LED driver. The input voltage
range is 2.9V to 22V with output voltage up to 25V. The
device is capable of driving up to 7 white LEDs. The high
side sense enables a single-wire LED connection by taking
advantage of the available system ground. This reduces
connector cost and complexity.
The device includes a current mode PWM controller,
260mA power switch, and high performance Schottky
rectifier. The LED driver eliminates external compensation
components for minimum solution size.
The wide input voltage range and low standby current are
ideal for portable devices. The high input voltage allows
direct connection to multi-cell battery packs which
increases operating efficiency and extends battery life.
Output current is programmed with an external sense
resistor up to 100mA (Boost) or 200mA (Buck). The device
provides ±5% constant current accuracy across the entire
operating temperature range.
A logic level PWM dimming signal may be applied directly
to the enable (EN) pin - for direct PWM dimming with a
wide dimming range. Output OVP (over voltage protec-
tion) protects the SC4541 from open circuit faults in the LED
string or connector. External OVP programming resistors
are not required.
The SC4541 is available in low profile MLPD-UT and
SOT23,6-pin packages. The device is rated across the
temperature range -40°C to +85°C.
Typical Application Circuit
V_IN 2.9V to 22V
Boost Topology I_OUT up to 100mA
L1
C1
10μF
1μF
IN
SW _OUT ^{VOUT Up to 25V}
SC4541
C2
1μF
RS
10Ω
PWM
Dimming
EN _GND FB
7 WLED @
20mA
Version 1.3
© 2011 Semtech Corporation
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