Current Sensoring with AMC1200B

Florian Hoermannsdorfer

Other Parts Discussed in Thread: AMC1200

Hello,

i have a question regarding to the outgoing signal on the AMC1200B Amplifier.

How do i get the Offset on it. I messure only the gained ingoing signal between the Pins VOutP and VOutN.

In my case VDD1 and VDD2 are 5V. The Ingoing signal was U_in = 41mV and on the Outgoing Pins i meassured U_out = 331mV which is 8*U_in. So i miss the Offset of U_offset = 2.55V.

Thanks foru your help

Best regards

Florian

over 10 years ago

0 Tom Hendrick over 10 years ago

TI__Guru**** 183061 points

Hi Florian,

What are the values of VoutP and VoutN when you measure against GND2?

0 Florian Hoermannsdorfer over 10 years ago in reply to Tom Hendrick

Prodigy 40 points

Hello Tom,
between VoutN and GND2 are 2.36 V. VoutP and GND are 2.69 V.
Thank you
Best regards
Florian

0 Florian Hoermannsdorfer over 10 years ago in reply to Florian Hoermannsdorfer

Prodigy 40 points

I still have the problem. Do I have to connect VoutN and GND2 together?

0 Tom Hendrick over 10 years ago in reply to Florian Hoermannsdorfer

TI__Guru**** 183061 points

Hi Florian,

When I asked you to measure VoutN and VoutP with respect to GND2, you had voltages of 2.36V and 2.69V which is correct. You have the 2.55V offset +/- your input voltage * the gain. When you measure between the two outputs, you are measuring the difference in their potentials - the 2.55V common mode won't be seen by your meter.

What are you trying to accomplish? If you want to see a signal riding on the common mode output perhaps it would be best for you to add a differential to single ended output stage.

0 Florian Hoermannsdorfer over 10 years ago in reply to Tom Hendrick

Prodigy 40 points

Hello Tom,
now I understand my failure. My first thought was I get the input*gain + offset between VoutN and VoutP.
Thanks for your help
Best regards
Florian

0 Tom Hendrick over 10 years ago in reply to Florian Hoermannsdorfer

TI__Guru**** 183061 points

Great! Have a nice day and please do let us know if you have further questions about the AMC1200.

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Current Sensoring with AMC1200B