INA181-Q1: Current sense amplifier reference voltage issue

Manikandan s

Part Number: INA181-Q1
Other Parts Discussed in Thread: INA181

Hi Greetings,

Our requirements is to measure current range 1-1000A. we are using current sense amplifier P.NO: INA181A2.For this amplifier am using the supply as 5V and Ref as 2.5V.In this case I couldn't able measure less than 4A. while simulating the model am getting the continuous ramp signal even tried with the different transition time also. I have attached the reference circuit i.e, current sense , 4A and 400A graph plot also.

One thing I have identified is that when am using exactly reference volt as Vs/2 this issue was occurs.

please suggest some inputs for resolving the issue.

Thanks in advance,

Best Regards,

Manikandan S.

over 1 year ago

0 Guang Zhou over 1 year ago

TI__Mastermind 30810 points

Hi Manikandan,

In the second plot where the current is a ramp, the current changes by less than 10mA which translates into <12.5uV change in INA181 output. On the other hand, the vertical full scale is 5000uV, this is probably why the output appears to be a flat line.

Regards, Guang

0 Manikandan s over 1 year ago in reply to Guang Zhou

Prodigy 30 points

Hi Guang,

Thank you for the response,

I have increased the transition time from 1ms to 1s. Still am getting the same ramp signal.

Best regards,

Manikandan S.

0 Guang Zhou over 1 year ago in reply to Manikandan s

TI__Mastermind 30810 points

Hi Manikandan,

Instead of VOUT, try to plot VOUT-2.5V. Then the above figure should look better.

Regards, Guang

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INA181-Q1: Current sense amplifier reference voltage issue