High DC voltage conditioning circuit how does it works ?

[IGBTSiC]

Hi,
I have found DC VOLTAGE CONDITIONING circuit in "25kW WolfPACK FM3 Six-Pack Inverter" from Wolfspeed eval board. I do not understand how does it works because I have always use voltage measurement with galvanic isolation e.g. based on AMC1200.
DC voltage is not connected with signal ground elsewhere. Why they do not use the parallel resistor Rs (marked in red color on the figure) for voltage droop? Could someone explain how this measurement circuit works ?

[Andy Chee]

This is just a differential amp configuration with a really, really, really big voltage divider.

https://www.electronics-tutorials.ws/opamp/opamp_5.html

[IGBTSiC]

Thanks, but it has no difference that in circuit from wolfspeed they connected resistors R37 and R153 directly to the inputs of OA ? In differential amp. configuration, the R1 and R2 are connected from the source side. The gain will be the same i.e. Vo = R3/R1 (Vin+ - Vin-) ?

[IGBTSiC]

I have done the simulation in LTSPICE. Yes exaclly this is the diferntial aplication of OA. Thank you.