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Isolating grounds from motors and a microcontroller

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nford

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Hi

I a designing a circuit with a microcontroller, and a series of high current motors. I need to isolate the grounds from each other so that the noise from the motors doesnt cause the microcontroller to shut down.

Do I just keep two grounds and separate and join them at the supply with an inductor and some caps? Any advice would be great.
 

kender

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Re: Isolating grounds

nford said:
Do I just keep two grounds and separate and join them at the supply with an inductor and some caps? Any advice would be great.

This is calle "start ground" and will certainly help isotate the noise from the motors. You might also consider the optical isolation of a microcontroller from the motors. Run the digital signals through optocouplers and use an isolated DC-DC converter (such as NMH0505, for example) to supply the power across the isolation barier. This would be the ultimate solution to stop the noise from the motors.
 

kicha

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Re: Isolating grounds

sir
the optical isolation of a microcontroller from the motors use this reference circuit you can use tlp250 also just reffer data sheet of tlp250 if need more on mail to id india_kitcha@yahoo.co.in
regards
kicha
 

nford

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Re: Isolating grounds

Thanks for the replies

I have already thought of using optocoupling. My problem is that I dont know of an easy way of sending back an analog signal through optocouplers. Also, it is expensive since I have 24 digital signals from the microcontroller to motor drivers and 8 analog signals back from motor drivers.
 

Troela

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Re: Isolating grounds

Check out the new isolators from analog devices. You can sample them.

h**p://www.analog.com/en/subCat/0,2879,767%255F827%255F0%255F%255F0%255F,00.html
 

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