For a small microcontroller application I need a power supply (230V) which is backed up by accumulators (sort of a DC USV). If power goes down, the accumulators have to keep the Vcc of the application board up until the mains power returns.
This is typically done by an ordinary USV. Hower, most of these are either too big for the available space, or too expensive. It should not be necessary to pay 100 € or more for such a simple thing.
This seems to be a very primitive requirement, but after searching the internet during several days, I could not find any acceptable solution.
Can somebody help? Has Elektor published a circuit for this purpose (or a similar one)?
Thank you very much for your help!