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Zek_De
Zek_De
Senior
May 8, 2026
Question

Motor Driver Fully Isolated shunt reading

  • May 8, 2026
  • 2 replies
  • 216 views

Hello everyone, I am currently working on a fully isolated motor driver using an STM32G474RE. I need to interface the AMC1301differential output to the MCU in a way that ensures accurate measurements. What is the best approach to achieve this? Also in mc workbench app, MCU opamp -> ADC hardware variant for Current sense -> InternalOpamps -> Differential -> InternalPGA. Or I will make the diff to single like in other picture wich looks easier. Also looks same with design below.

Zek_De_1-1778338412280.png

 



Zek_De_0-1778280329003.png

Zek_De_0-1778338366696.png

 

 

 

2 replies

MasterT
MasterT
Lead II
May 10, 2026

G474re has ADC capable to run differential mode, so take example Fig.8-1. Power Vdd2 by 3.3V from st side to stay safe. I see amp has BW ~200 kHz, so if you are not designing low power kind of app., than run ADC at full scale, for 12- bits about 2.8 Msps and also set OVS - oversampling. Again, depends on required BW OVS may vary from 8- to max 256, and provide up to 16-bits resolution for free

 

Screenshot From 2026-05-10 16-46-27.png

    Zek_De
    Zek_DeAuthor
    Senior
    May 14, 2026

    Zek_De_0-1778766665086.png

     

    Zek_De_1-1778766689800.png

    if I use amc1301 and diff mod of MCU , then what I will choose these numbers. for example 
    Polarization offset -> 1.44? because 0 current mean amc1301 produce 1.44 V for each out, PGA = 0. what about offset network attenuation?. Or I will choose to convert to diff to single line and direct to MCU . I already know about that.  But diff mode advantage is two line can travel more in PCB without problem

    MasterT
    MasterT
    Lead II
    May 14, 2026

    My understanding, that those calculators were not designed for amc1301. So, select one option, use amc1301 and ditch calculators, or use calculators and ditch amc1301

    Zek_De
    Zek_DeAuthor
    Senior
    May 14, 2026

    I think we can use it, 1.44 polarization, 1 is offset  network attenuation, but I want to be sure,because design is expensive no chance for mistake, I need an approve

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