I'm just wanting to confirm that this circuit would be safe/reliable to implement. I'm hoping to run two servos – one 6V one 7.4V – in parallel with an ESP32 dev board with built-in linear regulator, from an already regulated 7.4V source. Each regulator is a store-bought module with all surrounding circuitry.
The first switching regulator is pretty tolerant to current draw so I'm not too concerned about voltage sag under load (also servos using maximum stall current will be unlikely). Am also not too worried about voltage ripple to each servo from the switching regs. I've heard that sharing current can be an issue between linear voltage regs in parallel, so am hoping a switching reg doesn't have the same problem and have used it in place.
I'm pretty sure I should also have Schottkey diodes on each separate voltage line but wanted to confirm if any other problems may arise. Appreciate any feedback, thank you.
Best Answer
I would run the 6V reg directly from the 11.1 volt supply too, then run the LDO from 6V instead. This would isolate the higher power servo from the others and also reduce the LDO losses.
You might even consider using a switcher to make 3.3V direct from the battery too. TI and others make triple DCDC devices that would meet your spec and reduce your chip count.
Your power sequence depends more on keeping the servos quiet until the ESP32 comes up, so you should design a reliable ‘mute’ signal to disable them.