Ground Isolation

[seware]

I have a project in the design phase that I need a bit of advice on.

The project has two circuit stages both powered from the same power supply:

1)Generate bit stream via microntroller
2)Amplify and output bit stream

The project has a high potential for short circuit across the output, so I
am planning to use a fast optocoupler to provide some isolation on the bit
stream line to protect the microcontroller from feedback spikes. But can't a
spike feedback through the shared ground as well? How do I go about
isolating the ground between the two stages while feeding them from the same
power supply. My only idea from my very few years of electronics is an
isolation transformer. Any other ideas or am I going at this from the wrong
direction. Thank you and Merry Christmas!

Steve

 

[John Popelish]

seware wrote:

I have a project in the design phase that I need a bit of advice on.

The project has two circuit stages both powered from the same power supply:

1)Generate bit stream via microntroller
2)Amplify and output bit stream

The project has a high potential for short circuit across the output, so I
am planning to use a fast optocoupler to provide some isolation on the bit
stream line to protect the microcontroller from feedback spikes. But can't a
spike feedback through the shared ground as well? How do I go about
isolating the ground between the two stages while feeding them from the same
power supply. My only idea from my very few years of electronics is an
isolation transformer. Any other ideas or am I going at this from the wrong
direction. Thank you and Merry Christmas!

Steve

If the supply is isolated from Earth and all you are worried about is
a short circuit across the output, all you need is some sort of
current limit built into the output, because a short between either
side of the output signal and Earth would close no circuit.

--
John Popelish