I'm looking for an alternative for a backup battery i'm planning to use.
PCB is powered by 24V DC power supply. I'm using a 3.3V LDO in combination with 3,6V battery to power mcu and other components (~20 mA):
It would be more convenient to use a supercap. The application only needs to run for a couple of seconds (@20mA). I'm worried about inrush current so my proposed solutions would be adding a resistor (1). However this will result in a bigger capacitor. Besides my Vsense line is no longer available to detect lost +24V supply:
So what do you think about using a supercap with series resistor (for charging) and a schottky diode for uncharching? +24V supply failure will be detected on the +24v side: