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Topic: Connecting logic and motor power GND - advice please? (Read 415 times) previous topic - next topic

AgeingHippy

Hello All

I am building a simple motor controller using an SN754410 quad half-h bridge driver.

This driver is capable of accepting 2 voltages - for the logic and for the motors.

Now, assuming the power supply of the logic is seperate to the motor power supply, I guess I need to connect the two GND wires together.

It is my understanding that a motor can create noise on the line so I was wondering whether I should fit smoothing capacitors to between Vmot and GND and Vlogic and GND.

If so, what capacitance should these capacitors be? And why if possible.

Thanks


Grumpy_Mike

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I guess I need to connect the two GND wires together.

Yes see:-
http://www.thebox.myzen.co.uk/Tutorial/Power_Supplies.html

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I was wondering whether I should fit smoothing capacitors to between Vmot and GND

Yes see:-
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

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what capacitance should these capacitors be?

So they are big enough and cut out high frequencies typically use a 0.1uF and a 47uF

AgeingHippy


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