Linear's LT3756 drives high-current LEDs
Linear Technology
LT3756 DC/DC converter
Linear Technology has released the LT3756, a 100V, high-side current sense DC/DC converter designed to drive high-current LEDs.
Its six to 100V input voltage range makes it ideal for a variety of applications, including automotive, industrial and architectural lighting.
It uses an external N-channel MOSFET and can drive up to 20 1A white LEDs from a nominal 12V input, delivering in excess of 70W.
It incorporates a high-side current sense, enabling it to be used in boost, buck, buck-boost or SEPIC and flyback topologies.
The LT3756 can deliver efficiencies of more than 94 per cent in boost mode, eliminating the need for external heat sinking.
A frequency-adjust pin allows the user to program the frequency between 100kHz and 1MHz, optimising efficiency while minimising external component size and cost.
Combined with a 3 x 3mm QFN or a thermally enhanced MSOP-16 package, the LT3756 offers a very compact 70W LED driver solution.
The LT3756 uses True Color PWM dimming, delivering constant LED colour with dimming ranges up to 3,000:1.
For less demanding requirements, the CTRL pin can be used to offer a 10:1 analogue dimming range.
Its fixed frequency, current mode architecture ensures stable operation over a range of supply and output voltages.
A ground-referenced voltage FB pin serves as the input for several LED protection features, allowing the converter to operate as a constant-voltage source.
Two versions of the LT3756 are available.
The standard LT3756 offers an Open LED Status pin and the LT3756-1 replaces the Open LED Status pin with a frequency synchronisation pin.
Both the LT3756EUD and LT3756EUD-1 are available from stock in a 16-pin 3mm x 3mm QFN package.
The LT3756EMSE and LT3756EMSE-1 are both available in a thermally enhanced MSOP-16E package.
Also available from stock are extended temperature versions, or 'I' grades, namely the LT3756IUD and LT3755IUD-1.
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