For a simple discrete DO design approach, a local microcontroller would interface with an optocoupler, a FET driver, and a MOSFET. This method does facilitate design flexibility, as a designer can choose many different drivers with integrated protection features as well as a vast selection of MOSFETs by blocking voltage and current capabilities. For an eight channel solution, multiplying the aforementioned single channel solution is feasible, but it may occupy too much space and dissipate too much power and heat. It makes sense to consolidate individual devices to multi-channel devices to save on power and PCB real estate.