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INA196: AC current sensing using INA 196

Part Number: INA196
Other Parts Discussed in Thread: INA240

Hi,

The  INA196 have bandwidth of 500KHz according to the datsheet.
I need to measure the current on an AC rail with 12V @ 200KHz switching.

Q1. Can I use INA196 for this purpose?

Q2. If Yes, Do the circuit attached can be used for the purpose?

Thanks in Advance
DEEPAK V

  • DEEPAK,

    Is this a PWM signal, and is the duty cycle fixed at 50%?  Also, I'm assuming this AC signal is just jumping from 0 to 12V, not -12V to 12V, which would work for the device because it is only unidirectional.  However, there are a few things to know about the INA196 - first is that it is not recommended for use with Vsense<20mV (see this article).  If you expect to measure small sense voltages generated by current through that sense resistor, I would consider other products, like the INA240.  The INA240 is built for PWM switching signals, though it is not a linear amplifier so you might have a little trouble at 200kHz, especially if the duty cycle changes (see this article).

    I see you have a 75Ω sense resistor which means you're probably measuring small currents, yes?  What range of currents are you thinking?

  • DEEPAK,
    Haven't heard back from you in a while so I'll assume you solved any design questions you had regarding this application. If that's not the case or you have followup questions, please come on back and post again here or in a new thread and we'll get right back to you.