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Ajay Kr

Prodigy 40 points

Other Parts Discussed in Thread: INA282

Hi,

I want to build a current sense circuit with the following configuration.

I sense : -50 mA to 500 mA (bidirectional)

Vcm : +/- 10V

Accuracy : +/-10 uA to +/-100 u A

Any help to identify the right part is appreciated. INA282 seems to be good fit. Does 10 mV full scale mean that it is the minimum voltage required to sense?

Regards,

Ajay

over 8 years ago

0 Rabab Itarsiwala over 8 years ago

TI__Expert 4595 points

Hi Ajay,
INA282 can sense 10 mV full scale which means that could be the maximum sense voltage for a application.
What is the output voltage range for your application. What supply voltages are you planning to use?

0 Ajay Kr over 8 years ago in reply to Rabab Itarsiwala

Prodigy 40 points

Hi Rabab,

Supply voltage for my application is between +/-15 V. I am free to choose Rshunt. The currents I want to measure is between -50 mA to 500 mA with am accuracy of 100 uA.

I hope I was clear.

Regards,
Ajay

0 Rabab Itarsiwala over 8 years ago in reply to Ajay Kr

TI__Expert 4595 points

Hi Ajay,
INA282 can accomodate +-9V supply. With Vref = 0, Vcm = 10 V, Rshunt = 0.3 ohm at room temp you are looking at about 1.4 % input refered error at full scale (500mA).

0 Ajay Kr over 8 years ago in reply to Rabab Itarsiwala

Prodigy 40 points

Hi Rabab,

Sorry, i do not understand it.

500mA with 0.3 ohm Rshunt results in 0.15 V of sense voltage, right? This is more than the maximum full scale Vsense which is 10 mV. Is INA282 still usable?

Regards,
Ajay

0 Rabab Itarsiwala over 8 years ago in reply to Ajay Kr

TI__Expert 4595 points

Hi Ajay,

That statement in the datasheet means that if there is an application with 10mV full scale Vsense, this device due to it's low offset and drift could be used with reasonable accuracy. But if you are not limited by that, the full range of the output could be utilized. Also for smaller current sensing this TIPD may be on interest:

http://www.ti.com/lit/ug/tidu033/tidu033.pdf

Also look into Current Shunt Monitor FAQs at the top of this page for more information on Current Sensing.

0 Ajay Kr over 8 years ago in reply to Rabab Itarsiwala

Prodigy 40 points

Thanks Rabab.

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