I am currently working on a PCB design that will be using 12VDC to power all of its components. It will be mounted on a vehicle, which is powered by an external power supply, which supplies the average voltage of 375VDC. I want to make the board bullet proof, and design it so that it can take up to 700VDC before bad things happen, and using the flyback converters is not an option. Most of buck converters have the maximum input lower than 100VDC.
The only solution I can think of, within my knowledge, is to use a voltage divider to bring the voltage down first, and then use a buck converter chip to get 12VDC. Would it be a valid option? Could anyone suggest better ways to solve this problem?