I am designing a digital board which will drive a very coarse (simple on-off) high[er] current speaker. I am worried that the switching of the speaker will cause noise in the power supply driving it. If this was the same power well as the microcontroller, that wouldn't be good.
I will use separate ground and power planes for the power to the amplifier circuit. I don't want to actually use a separate power supply for it's power plane, but think a simple filter might work better. Could I just put an inductor/choke between the "main" power plane and the amp's power plane? I envision with the capacitor, this would essentially form a low-pass filter.
Does this make any sense? Any considerations I should take in selecting values? What about even doing anything in board traces/geomentry to make a simple/crude inductor or provide other isolation?
If I were really concerned about this - I would use a separate power supply. I haven't built the circuit yet and am not seeing any specific problems, so I am just trying to sort of minimize any potential problems. Thus, doing a simple isolation as such might just be a quick and easy thing to do.
Any good tips?