Multi-channel LED Driver has 3,000:1 True Color PWM dimming.
September 14, 2009 -
Supplied in 32-pin, 5 x 5 mm QFN package, LT3754 can drive 16 channels - each with up to ten 50 mA white LEDs in series - from 12 V input while delivering efficiencies exceeding 92%. IC operates from 6-40 V input; utilizes step-up DC/DC controller; and offers features such as ±2.8% (±0.7% typ) LED current matching, programmable 100 kHz to 1 MHz fixed frequency operation, and current mode architecture. IC can drive up to 45 V of 50 mA LEDs per channel.
(Archive News Story - Products mentioned in this Archive News Story may or may not be available from the manufacturer.)
Original Press release
Linear Technology Corp.
1630 McCarthy Blvd.
Milpitas, CA, 95035
USA
Drive up to 16 Channels of Ten 50mA LEDs with 3,000:1 True Color PWM Dimming
MILPITAS, CA - September 10, 2009 - Linear Technology announces the LT3754, a 16-channel LED driver, utilizing a step-up DC/DC controller capable of driving up to 45V of 50mA LEDs per channel. Its internal 60V, 1MHz DC/DC boost mode controller is designed to operate as a constant current LED driver for up to 160 white LEDs. From a 12V input, the LT3754 can drive 16 channels, each with up to ten 50mA white LEDs in series while delivering efficiencies exceeding 92%. Its multi-channel capability makes it ideal for medium and large-sized TFT-LCD backlighting applications. Its input voltage range of 6V to 40V makes it ideal for automotive, avionic, HDTV and industrial display applications.
The LT3754 offers ±2.8% (±0.7% typical) LED current matching to ensure uniform brightness of the display. Dimming ratios as high as 3,000:1 can be attained by using True Color PWM(TM) dimming. A programmable 100kHz to 1MHz fixed frequency operation and current mode architecture offers stable operation over a wide range of supply and output voltages while minimizing the size of the external components. Additionally, the switching frequency is synchronizable to an external clock. Its thermally enhanced 5mm x 5mm QFN-32 package offers a very compact solution footprint for LED backlighting applications.
The LT3754 uses an external N-Channel MOSFET switch to provide a boost mode constant current source. However, even when VIN exceeds VOUT, the LT3754 will continue to accurately regulate the LED current. The internal boost controller uses an adaptive feedback loop to regulate the output voltage slightly higher than the required LED voltage to ensure maximum efficiency. If any of the LED strings experiences an open circuit, it will continue to regulate the existing strings and signals the OPENLED alert pin. If higher current LEDs are required, multiple strings can be combined, enabling the LT3754 to drive up to eight strings of ten 100mA LEDs or four channels of ten 200mA LEDs. Additional features include programmable overvoltage protection, LED current derating based on junction temperature and/or LED temperature and output voltage limiting when all LED strings are disconnected.
The LT3754EUH is available in a 32-lead 5mm x 5mm QFN package and is priced at $4.25 in 1,000 piece quantities. An industrial grade version, the LT3754IUH is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature and is priced at $5.00 each in 1,000-piece quantities. All versions are available from stock. For more information, visit www.linear.com.
Summary of Features: LT3754
Up to 45V of LEDs - 50mA, 16-Channel LED Driver
Wide Input Range: 6V to 40V
±2.8% LED Current Matching at 20mA (Typ ±0.7%)
Up to 3000:1 True Color PWM(TM) Dimming Range
Single Resistor Sets LED Current (10mA to 50mA)
LED Current Regulated Even for PVIN > VOUT
Output Adapts to LED VF for Optimum Efficiency
Fault Flag + Protection for Open LED Strings
Protection for LED Pin to VOUT Short
Parallel Channels for Higher LED Current
Programmable LED Current Derating vs. Temperature
Accurate Undervoltage Lockout Threshold with Programmable Hysteresis
Programmable Frequency (100kHz to 1MHz)
Synchronizable to an External Clock
Thermally Enhanced 32-Pin (5mm x 5mm) QFN Package
45V, 16-Channel Boost Mode LED Driver
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, µModule® products, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
LT, LTC, LTM, µModule and are registered trademarks and True Color PWM is a trademark of Linear Technology Corp. All other trademarks are the property of their respective owners.
Contacts
North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
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