• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 202 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Current sensor recommendation inquiry

MJ Jeon
Genius 5240 points
Other Parts Discussed in Thread: INA185, INA186

Hi, TI support team

Please recommend a product that meets the conditions below.

[Condition]

- Supply voltage =12V

-Normal current = 100mA

Please recommend a current sensor that can sense when DC 12V about 100mA flows and the current fluctuates (120mA).

- Application: small printer

Is there a product capable of current sensing in a step motor?

If so, please recommend.

Thanks.

Regards,

MJ

  • 0
    TI__Expert 6975 points

    MJ,

    Some information that would be helpful in making a recommendation for you is:

    what the input dynamic range is for your system,

    what the maximum error that the system can tolerate is,

    and what size shunt resistor is acceptable.

    Based on the information you have given me I would recommend the INA241A5 with a 400mΩ shunt resistor; I chose this because the INA241 has enhanced PWM rejection (and protection) and I am assuming you will be measuring a digital motor drive signal. This chip has an analog output, so if you were hoping to digitize the signal you would need an ADC as well. If you would like to use the chip bidirectionally, I would recommend using a 200mΩ resistor instead and holding the Vref pin at 6V.

    I used our error calculator, available here if you wish to use it, to plot the error for you:

    Here is a plot of the error for a 400mΩ shunt:

    And for a 200mΩ shunt:

    Let me know whether this chip and resistor will meet your specifications, or if your specifications require a different device.

    Levi DeVries

  • 0 in reply to Levi DV
    Genius 5240 points

    Dear, Levi

    Thanks for recommending the INA241A5.

    The customer is using a step motor and wants to design a cheaper solution than the recommended part.

    Since it is controlled by PWM, it is judged that it would be better to use the recommended part, but products such as INA185 and INA186 cannot be applied?

    please advise.

    Thanks.

    Regards,

    MJ

  • 0 in reply to MJ Jeon
    TI__Expert 6975 points

    MJ,

    Please see my above questions regarding your system requirements:

    Levi DV said:

    what the input dynamic range is for your system,

    what the maximum error that the system can tolerate is,

    and what size shunt resistor is acceptable.

    and please also tell me what supply voltages are available for the current sensor. Does this chip need to be bidirectional? And is the customer always planning to use it on the high side?

    These answers will help me to make a recommendation regarding the INA185 and INA186.

    Thanks,

    Levi DeVries