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INA225: Sensing between 10mA -> 50mA

kouki
Prodigy 170 points
Part Number: INA225


Hello,

I want mesure a standby current between  10mA -> 50mA of a Brushless single phase motor.  The Common mode voltage is arroud 27V. 

I choose the INA225 sensor. 

1 - How can i connect REF pin? 

2 - is it possible to mesure correctly currents between 10mA - 50mA with the INA225 sensor? 

Thank you! 

  • 0
    TI__Mastermind 32395 points

    Hello,

    What is the desired power suppy of the amplifier? Why did you choose the INA225? Why do you need an adjustable gain? What do you mean by standby current? Are you using pulse-width modulation for these 10mA -50mA currents, if so, what is the frequency?

    1. You drive the REF pin with a low-impedance power source such as an op-amp buffer as seen with this figure in the datasheet.

    2. You could use one gain for the INA225 and achieve a full dynamic range Vout for measuring ILOAD of 10mA to 50mA. If your high-side shunt resistor (Rsh) is 450mOhm and gain is 200V/V, then INA225 Vout = 900mV to 4.5V (assuming you reference the INA225 to ground).

    Best,

    Peter Iliya

    Current Sense Applications