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INA300: INA300

Yeh tab
Prodigy 10 points
Part Number: INA300


Hi, we are trying to adjust the INA300 current limit(#3 resistance) after enable,is this application is OK?

The INA300 pin3 original resistance is "A",  and after enable.

the"A" was parallel a MOS and resistor"B"

After turn on MOS  total resistance change to A//B. 

  • 0
    TI__Mastermind 26335 points

    Hello Yeh tab,

    Thanks for considering to use TI.  I suspect that if you are not careful in your design, you could potentially have large error in your output from the INA300.  I did some calculations on what I presume is your setup (below).  The variation of your mosfet rdson and what you assume it to be can really increase the amount of error you observe at the INA300 output.  Also, this would be adding to all the sources of error inherent in the INA300 (or any current shunt monitor device).  If you want more information on those sources you can go here: https://training.ti.com/getting-started-current-sense-amplifiers  

  • 0 in reply to Patrick Simmons
    TI__Intellectual 1770 points
    Hi Simmoms,

    Does INA300 able to change current limit level after INA 300 enable?

    For example:

    At beginning, I use 3A resistor for INA300 current limit.
    But enter power save mode, I will adjust Ilimit resistor to 500mA.
    Does INA300 able to change current limit without restart?

    Thanks
    Shaq.
  • 0 in reply to Shaquille Chen
    TI__Mastermind 26335 points
    Hello Yeh tab, Shaquille,

    I believe I may have misunderstood the original question now. I presumed you were adjusting the sense resistor. As for the Limit pin, the current cannot be adjusted. That pin sources current and you should expect that current to be between 19.85 micro-Amps and 20.15 micro-Amps. As for switching on a parallel resistor, you may see some transients from MOS parasistics that could incur a false trigger from your device. However, the INA300 device should still maintain normal functionality as long as all absolute maximum ratings are observed.