Linear new LED controller LT3755 can provide LED over 50W power

Linear Technology Corporation (Linear Technology Corporation) launched 60V, high side current detection DC/DC LT3755 converter, the device designed for driving high current LED. 4.5V to 40V input voltage range makes it suitable for a variety of applications, such as automotive, industrial and architectural lighting. The LT3755 uses an external N channel MOSFET that can drive up to 14 1A white LED, with a nominal 12V input, providing over 50W power. The device with high side current detection, can be used in the boost, buck, buck boost or SEPIC and flyback topology. The efficiency of the LT3755 in the boost mode can be achieved above 94%, without any external cooling measures. The frequency regulation pin allows the user to program the frequency in the range of 100kHz to 1MHz, thus optimizing the efficiency while minimizing the size of the external components and reducing the cost. LT3755 uses 3mm x 3mm QFN package, which can form a very compact 50W LED driver solution.

LT3755 uses True Color PWM dimming, with up to 3000:1 dimming range to achieve constant LED color. For less demanding dimming requirements, the CTRL pin can be used to provide 10:1 analog dimming range. The fixed frequency, current mode architecture allows stable operation over a wide supply and output voltage range. The ground voltage on the FB pin is used as an input to several LED protection functions so that the converter can work as a constant voltage source.

There are two versions of the LT3755: the standard LT3755 with an open LED status pin; and the LT3755-1 with a frequency synchronization pin to replace the open LED status pin. LT3755EUD and LT3755EUD-1 are available in 16 pin 3mm x QFN 3mm package, available from stock. To buy 1000 units in bulk, the price of each of the two versions are $2.75. Extended temperature version or "I" version (i.e. LT3755IUD and LT3755IUD-1), also available on the spot. Thousands of pieces of purchase price was $3.15 per piece.

Performance overview: LT3755/-1

3000:1 True Color dimming PWM

Wide input voltage range: 4.5V to 40V

Output voltage up to 60V

Constant current and constant voltage regulation

100mV high voltage side current detection

With boost, buck, buck boost mode, SEPIC or flyback topology driven LED

Adjustable frequency: 100kHz to 1MHz

Programmable undervoltage lockout with hysteresis

Open LED state pin (LT3755)

Frequency synchronization (LT3755-1)

PWM disconnect switch driver

CTRL pin provides analog dimming

Low shutdown current: 1uA

Programmable soft start

Heat resistant enhanced 16 lead QFN (3mm x 3mm) package

Source: International Electronic Business