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INA201: About current monitoring solution

Vera Mao
Expert 5065 points
Part Number: INA201
Other Parts Discussed in Thread: LMP8601, INA210, INA199

hi dear supporting team,

my customer want to get a current sensing solution which sense 12A current from +/-5V line, the precison need be 3mA.  do we have proper solution?

I saw the output of INA20* is from 4mV,  customer hope to get 0V. tks!

  • 0
    TI__Genius 15760 points

    Hi Vera,

    The output of the INA20x family starts from 4mV, you are correct. Same case for INA19x family. But this condition is true only when the Vcm<20mV. If your customer is planning to use this device with Vsense>20mV he should not have this problem. Please refer the customer to spec table (test conditions in the Output Section) on both datasheets. 

    Another option is the LMP8601. This device do not have the output limitation but it needs a 5V supply in order to accept the -5V Vcm. 

    Regards,

  • 0 in reply to Mayrim Verdejo
    TI__Expert 5065 points

    hi Verdejo,

    thank you for the answer!

    one more question, because the current could be both directions,  which means the Vsense will be positive and negative.  could customer still use INA20*?  And also 60mV is the max value only, if they have smaller than 20mV Vsense, which solution will be suggested?  tks!

  • 0 in reply to Vera Mao
    TI__Genius 14825 points
    Vera,

    The INA20x family does not have reference pins, and so are unidirectional and cannot be used for positive and negative Vsense. Since the customer is concerned with low Vsense values and 3mA resolution, I would suggest looking into something with low offset voltage.

    I am a little unclear as to what you mean by +/-5V rails. Does this mean the common mode of the device changes from -5 to +5, or does it mean that you'll be trying to power the device off +/-5V instead of 10V and GND, or something of that nature? If you could draw up a little schematic to clarify, it would help me with a part recommendation.
  • 0 in reply to Jason Bridgmon
    TI__Expert 5065 points

    hi Jason,

    thank you for supporting!

    the block is like below, the current has two directions.

  • 0 in reply to Vera Mao
    TI__Genius 15760 points
    Hi Vera,

    We are trying to understand the drawing but we are a little bit confused. Where is the load? Will this be high side or low side configuration?
  • 0 in reply to Mayrim Verdejo
    TI__Expert 5065 points

    hi Verdejo,

    sorry, it is my mistake, the block is as below, there is no +/-5V, just dual direction current need be detected (0~20A max),  and resolution should achieve 3mA.  pls help see whether there is any solution suggested:

  • 0 in reply to Vera Mao
    TI__Genius 15760 points
    Hi Vera,

    New diagram shows Vcm = 5V, needs to be able to measure bidirectional current, including 0A. Correct? What is the supply voltage needed and output needed?

    Customer can take a look at INA210 or INA199 family of directional current shunt monitors with voltage output.
  • 0 in reply to Mayrim Verdejo
    TI__Expert 5065 points

    hi Verdejo,

    thank you for the recommendation!

    the power supply customer may accept is 12V max, while they oriignally use one ADC which only  accept 2Vpp input range. I will try INA21* with customer.