EVSPIN32F02Q1S1 Current Sensing

[kenni]

Hello,

I'm planning to design a motor driver using the STSPIN32 IC on the evaluation board EVSPIN32F02Q1S1 and was going through the schematic when I noticed this current sensing circuit:

I understand that R34, 36, and 111 are used as single shunt sensing, but I don't get why what the point of having R33 and C22, are they for some form of biasing?

I'm also unsure of the function of R38 and R57.

Basically, can someone explain what the point of having R33, C22, R38, and R57 as part of current sensing circuit?

[GMA]

Dear Kenni,

Please have a look to this current sensing application note AN5397.
R57 is a MOSFET gate pull down and C22 prevent high frequencies to reach opamp stage.

[kenni]

Hello,

Thank you for the your response, it was helpful. I have a follow up question regarding the necessity of U3C, since overcurrent protection is already done with CIN, is there a reason why U3C is employed to do another overcurrent protection?

[GMA]

Hello,

I am not familiar with this board but, it is often proposed flexibility between mcu internal/external current sensing or over current protection.