HB LED driver
23 April 2012
100V constant-current and constant-voltage controller with input and output current sense.
Linear Technology’s LT3796 is a 100V, high-side current sense DC/DC controller designed to regulate a constant-current or constant-voltage that is ideal for driving high brightness (HB) LEDs.
Its 6V to 100V input voltage range supports a wide variety of applications, including automotive, industrial and architectural lighting. The LT3796 uses an external N-channel MOSFET and can drive up to 85V of white LEDs from a nominal 12V input, delivering in excess of 50 Watts. The LT3796 is ideal for charging batteries or supercaps at constant current and voltage. The LT3796 incorporates a high-side current sense, enabling its use in boost, buck, buck-boost or SEPIC and flyback topologies. Additionally, it offers both input and output current limiting and monitoring for added reliability and design flexibility.
The LT3796 can deliver efficiencies of over 94% in boost mode, minimising the need for external heat sinking. A frequency adjust pin enables the user to program the frequency between 100kHz and 1MHz, optimising efficiency while minimising external component size and cost. Combined with a thermally enhanced TSSOP-28 package, the LT3796 offers a highly compact HB LED driver or charger solution.
The LT3796 uses True Colour PWM dimming, which delivers constant LED colour with dimming ranges of up to 3,000:1. For less demanding dimming 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 wide range of supply and output voltages.
Robust open and short-circuit protection maximise overall system reliability, whereas C/10 detection optimises both battery and supercap charging designs. Additional features include frequency synchronisation, programmable UVLO and a programmable fault restart timer.
The LT3796EFE is available in a thermally enhanced TSSOP-28 package.
Contact Details and Archive...