Author Topic: reading current of Power Supply  (Read 2083 times)

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Offline AmirTheGreatTopic starter

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reading current of Power Supply
« on: March 16, 2013, 11:51:36 pm »
Hey everyone,


I'm making a simple power supply with an LM317. I want to be able to read the output voltage and current with an arduino and display it on an lcd or something.
I made a voltage divider so I can do an analog read of 0-5v and calculate the Vout. But Im not sure how to measure the voltage drop of the shunt resistor since i would have to connect the other end to the arduino's ground which would short the whole circuit and what-not.

how would I be able to measure the current?

(wasn't sure whether to post in Microcontrollers/ FPGAs or Projects/Designs so I apologize for spamming the Beginners Forum.)
but there is a good chance I'm wrong.
 

Online Monkeh

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Re: reading current of Power Supply
« Reply #1 on: March 17, 2013, 12:22:54 am »
Use a low-side shunt.
 

Offline AmirTheGreatTopic starter

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Re: reading current of Power Supply
« Reply #2 on: March 17, 2013, 12:49:36 am »
Thanks for your advice.
is there any improvements I could make?
I will add capacitors by the way
but there is a good chance I'm wrong.
 

Offline Rerouter

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Re: reading current of Power Supply
« Reply #3 on: March 17, 2013, 01:07:46 am »
one big one, move the lm317's feedback network to the other side of the current shunt, this ensures its voltage drop does not matter
 


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