Power supply configuration across isolation barrier

A powered device, comprising:

• a digital addressable lighting interface (DALI) connected to a load to be powered by a power source;
• an opto-isolator connected to the DALI;
• a controller positioned on a primary side of the opto-isolator, the controller configured to generate a first signal to select whether to provide power to the opto-isolator so that the opto-isolator is conducting or not conducting, wherein when the opto-isolator is conducting the DALI has a maximum current value and when the opto-isolator is not conducting the DALI at a zero current value, the controller further configured to generate a modulated second signal to provide power to the opto-isolator, so that the opto-isolator is conducting with a duty cycle and frequency, and wherein the DALI has a selected current value between the zero current value and the maximum current value, based on the modulated second signal;
• and
• a buck converter receiving a current reference based on a voltage reference based on the second signal, the buck converter configured to output a fixed voltage to the DALI.