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INA220 / application circuit

S.Satoshi
Guru 21685 points
Other Parts Discussed in Thread: INA220

Hi,

Our customer plan to use INA220 as attached configuration to measure LDO's input current and output voltage. Can you please check attached and give your comments?

Best Regards,

Sonoki / Japan Disty

To measure LDO’s input current and output voltage by using INA220.pdf
  • 0
    TI__Mastermind 25865 points

    Sonoki-san,

    Circuit should work.

    Have customer make filter resistors <10ohms and Kelvin-connect shunt resistor. Remember supply bypass capacitor.

  • 0 in reply to Pete%20Semig
    Guru 21685 points

    Hi, Pete Semig-san,

    Thank you for your quick response. I will request our customer to try the circuit by using EVM.

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    Guru 21685 points

    Hi Pete Semig-san,

    I'm sorry but please let me ask again one more.

    Can customer complete to take voltage and current information within 10msec? I believe that the 10msec is enough to do it because the worst case of ADC Conversion Time is 586usec. Anyway I would like to have your  comments.

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    TI__Mastermind 25865 points

    Hello Sonoki-san,

    Yes, can measure shunt and bus voltage in 10ms. ADC conversion time depend on number of bits. 12-bit, 'B' grade, maximum conversion time 586us.

    Shunt voltage conversion=586us
    Bus voltage conversion=586us
    Total Conversion time=1.172ms

    Can add averaging for more accuracy because 1.172ms<10ms.

    Example: Change ADC conversion time to 4.26ms (Table 5 in data sheet). This averages 8 samples.

    Shunt voltage conversion=4.26ms
    Bus voltage conversion=4.26ms
    Total Conversion time=8.52ms

    Calculation of current and power from shunt and bus voltage does not add to overall conversion time (data sheet page 14).

  • 0 in reply to Pete%20Semig
    Guru 21685 points

    Hi Pete-san,

    Thank you for your detailed answer. I recommend to use averaging operation for better accuracy.

    Best Regards,

    Sonoki