Analog Devices has released the Power by Linear LT3762, which is a 60-V output, high efficiency, synchronous, boost LED driver controller with a programmable internal LED PWM signal generator and spread spectrum frequency modulation that yield low EMI noise. The versatile LT3762 includes a rail-to-rail current sense amplifier, enabling high- or low-side current sensing that, in addition to synchronous boost, facilitates synchronous buck and buck-boost mode topologies and nonsynchronous SEPIC designs.
The LT3762’s 2.5- to 38.5-V input voltage range and synchronous operation suits it for automotive power systems, portable instruments, industrial applications, medical instruments and architectural lighting. An auxiliary on-chip buck-boost converter provides the necessary gate drive voltage in low voltage systems, and when combined with a 500-µA maximum quiescent current and 1-µA shutdown current (TA = 25°C), results in high efficiency over wide input voltage and output current ranges.
The LT3762’s optional spread spectrum frequency modulation can be enabled to reduce the effective switching frequency noise for systems where EMI is a concern. An on-chip PWM signal generator is synchronized to the internal oscillator for lowest noise performance. Internal PWM generation provides 250:1 dimming; external 3000:1 dimming or analog dimming can also be employed.
Other features of the constant current and constant voltage LT3762 include current mode operation with cycle-by-cycle current limiting, adjustable 100-kHz to 1-MHz switching, programmable undervoltage lockout, open LED and short-circuit protection with fault status indicators, LED overcurrent protection, and thermal shutdown. The part is available in thermally-enhanced 28-lead TSSOP and 4- by 5-mm QFN packages. Three temperature grades are available, with operation from –40°C to 125°C (junction) for the extended and industrial grades, and a high temperature grade of –40°C to 150°C.
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