Demonstration circuit 1268B is a high voltage and high current LED driver controller featuring the multitopology, constant current, constant voltage LT3755-2 (1268B-A) or LT3755-1 (1268B-B). The LT3755-2 features an OPEN LED status pin, while the LT3755-1 allows external frequency synchronization. The demonstration circuit is assembled as a boost topology with an 8V to 40V input voltage range, 1A LED current and up to 54V LED forward voltage.
The DC 1268B features PWM dimming, analog dimming, shutdown, and open LED overvoltage protection. Open circuit LED protection clamps the LED voltage at 56V, though the ICs can provide an output voltage up to 75V.