Synchronous boost LED controller with 60V output

The versatile LT3762 includes a rail-to-rail current sense amplifier, enabling 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 LT3762’s 2.5 to 38.5V input voltage range and synchronous operation is suited 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 low 500µA maximum quiescent current and 1µA shutdown current (TA = 25°C), results in high efficiency over wide input voltage and output current ranges. 

In systems where EMI is a concern, the LT3762’s optional spread spectrum frequency modulation can be enabled to reduce the effective switching frequency noise. An on-chip PWM signal generator is synchronised to the internal oscillator for lowest noise performance. Internal PWM generation provides 250:1 dimming; external 3000:1 dimming or analogue 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 100kHz to 1MHz switching, programmable undervoltage lockout, open LED and short-circuit protection with fault status indicators, LED overcurrent protection and thermal shutdown. 

The LT3762 is available in thermally enhanced 28-lead TSSOP and 4x5mm QFN packages. Three temperature grades are available, with operation from –40 to +125°C (junction) for the extended and industrial grades, and a high temperature grade of –40 to +150°C.