We are developing an industrial controls product that will be used to monitor the presence or absence of voltage ranging from 5V to 480V. Since the unit will be generic and programmable, this input may be used in a variety of unpredictable ways.
The problem I have been wrestling with is how to monitor such a wide range of voltages with a single circuit design. For example, if I drive an optocoupler LED directly, I can't get the 5V to turn it on without the 480V destroying it. Voltage regulators typically operate on much lower voltage than 480V, so I'm in a bit of a dilemma.
The industrial controls solutions I've seen get around this problem by saying, "purchase this other model for high voltage input" or "buy this high voltage input converter and add it on." Is that really the only solution here? Am I trying to do the impossible? Any input would be appreciated, no pun intended!