• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 30 subscribers
  • Views 574 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

Drv8432 current sensing

ALbert Tello
Intellectual 735 points

Hi Ryan

The datasheet mention  in Max  Absolute Rating:     GND_X to GND          –0.3 V to 0.3 V

If we have current sense RA,RB,RC,RD in the low end  and drop is bigger of 100 mV  for example  160mV

we still down of the   Absolute , can demage the IC  for  a resistor 0.04 at 4 Amp ?

Regards

Albert

  • 0
    TI__Guru** 114905 points

    Hi Albert,

    I am not sure I understand the question.

    If the voltage at GND_A, GND_B, GND_C and GND_D with respect to GND is less than +/-300mV, it is within the absolute ratings.

    Please note these measurements should be taken at the device pins. GND can be different across the PCB.

    Please provide more details if this did not answer your question.

  • 0 in reply to Rick Duncan
    Intellectual 735 points

    Sorry Rick for the delay , and Thank you very much


    The problem is when our customers  use  steppers from 1 Amp to 4 Amp stepper in same board ,  at low winding current   i.e. Stepper : 1 Amp  

    Microsteping from 64- to 256  steps/REV becomes difficult  provide these resolutions .

    Question 1: if GND_A,GND_B,GND_C,GND_D, with respect to GND  around 240 mV with a shunt resistor of 0.06 Ohms  (low END) Low Inductance, I would like to know you opinion on this ?

    Question 2 : If  in addition 2 resistor in high end is added  (one per full H-Bridge) Value  i.e.  0.2 Ohms, to the four low end already has , What  is your comments on that ? or is another way to support motor from 1Amp to 4 Amp

    If you have any questions please let me know.

     

    Albert 

  • 0 in reply to ALbert Tello
    TI__Guru** 114905 points

    Hi Albert,

    ALbert Tello said:
    Question 1: if GND_A,GND_B,GND_C,GND_D, with respect to GND  around 240 mV with a shunt resistor of 0.06 Ohms  (low END) Low Inductance, I would like to know you opinion on this ?

    I am assuming you are using a current sense amplifier to measure the chopping current. Have you considered placing an adjustable gain on the amplifier based on current? 

    ALbert Tello said:
    Question 2 : If  in addition 2 resistor in high end is added  (one per full H-Bridge) Value  i.e.  0.2 Ohms, to the four low end already has , What  is your comments on that ? or is another way to support motor from 1Amp to 4 Amp

    Adding additional resistors in the high side should be no problem, but it will be less efficient as there is a .8V drop across the resistor and if you stop at 4A, there is 3.2W through the resistor.