Synchronous boost LED controller ideal for automotive, industrial and medical applications

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