DC to DC Power Supplies (Converters)
DC/DC Converter drives up to 20 LEDs.
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Press Release Summary:
Housed in 3 x 3 mm, 10-lead DFN package, LT3466 dual, full function, step-up DC/DC converter drives up to 20 white LEDs from one Li-Ion battery. Current mode and fixed frequency operation ensure uniform LED brightness, and 2 independent converters are capable of driving asymmetric LED strings from input voltage of 2.7-24 V with efficiencies to 81%. Switching frequency can be set between 200 kHz and 2 MHz via one resistor.
Original Press Release:
Dual High Efficiency White LED Drivers with Integrated Schottkys Can Drive up to 20 LEDs from a 3 x 3mm DFN
MILPITAS, CA - March 22, 2004 - Linear Technology announces the LT3466, a dual, full function, step-up DC/DC converter specifically designed to drive up to 20 white LEDs from a Li-Ion battery. Its high efficiency, current mode and fixed frequency operation ensure uniform LED brightness, low noise and maximum battery life, while on-chip Schottky diodes eliminate both the added cost and space requirements of external diodes. The LT3466 contains two independent converters capable of driving asymmetric LED strings (up to 10 in series per converter) from an input voltage of 2.7V to 24V, delivering efficiencies up to 81%. Its 3 x 3mm DFN package and tiny externals provide a very compact footprint for space-constrained handheld applications.
The LT3466 switching frequency can be set between 200kHz and 2MHz via a single resistor, enabling the designer to minimize solution footprint and maximize efficiency. A constant frequency PWM architecture minimizes noise. Its 2.7V to 24V input voltage range enables it to operate in applications ranging from Li-Ion powered handheld devices to automotive backlighting. The LT3466 acts as a constant current source, delivering the same current to each white LED. This ensures uniform LED brightness regardless of fluctuations in the LED's forward voltage drop, which vary with temperature, manufacturing tolerances and age. The two independent step-up converters are capable of driving asymmetric LED strings, with independent dimming and shutdown control of each string. Additional features include internal soft-start/inrush current limiting, and open LED protection. The combination of the LT3466's high efficiency, versatility, low noise, and extremely small "total solution" footprint make it ideal for variety of backlighting applications that require many white LEDs in a tiny form factor.
The LT3466 is available from stock in a low profile (0.75mm) 3mm x 3mm DFN-10 package. Pricing starts at $2.20 each for 1,000-piece quantities.
Summary of Features: LT3466
Drives Up to 20 White LEDs from a 3.6V Supply
Two Independent Step-Up Converters Capable of Driving Asymmetric LED Strings
Independent Dimming and Shutdown Control of the Two LED Strings
Integrated Schottky Diodes
Inherently Matched LED Current
High Efficiency: Up to 81%
Internal Soft-Start Eliminates Inrush Current
Open LED Protection
Fixed Frequency Operation: Programmable up to 2MHz
Wide Input Voltage Range: 2.7V to 24V
3mm x 3mm 10-Lead DFN Package
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators,power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequencydevices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.
Note: LT, AND LTC are registered trademarks of Linear Technology Corp.
