INA240: INA240A1's accuracy

Yuan Tan63

Part Number: INA240

Hi,

customer are usins INA240A1 to replace AD8210 to do current sensing for motor drives.

when no PWM, INA240A1 performs better; when here is PWM, the accuracy changed a lot, worse than AD8210. f=10kHz. here is sch and waveforms:

over 5 years ago

0 Guang Zhou over 5 years ago

TI__Mastermind 30330 points

Hi Yuan,

Are “Ib” and “Ia” for AD part and INA240 respectively?

It appears the differential input is 0V, with the common mode voltage being chopped. At 10KHz, the period is 100uS, how is the 200uS sampling period synchronized with the PWM? What is the wait time after each PWM transition?

Also what is the value of the shunt?

In addition, the 470nF cap is fairly large comparing to the 22Ohm, the output might be slightly oscillating, please check. The combination can probably be adjusted to 100nF and 150Ohm.

Regards, Guang

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Yuan,

has your thread to do with this thread?

Kai

0 Guang Zhou over 5 years ago in reply to kai klaas69

TI__Mastermind 30330 points

Hi Yuan,

Looks like this issue is being addressed in another thread, lets close this one.

Regards, Guang

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INA240: INA240A1's accuracy