My needs
1.I Want to know the internal circuit of ADC module current channel inside the chip.
2.According to the schematic diagram given, please help to draw the equivalent circuit diagram of current acquisition.

I use pin IN+ and IN- to measure current.The configuration of ADC0CON is shown in the picture below.

And I use internal reference(1.2V).

The Current ADC (ADC0) Functional Overview I have already read, but I couldn't understand.So, please help to draw the equivalent circuit diagram of current acquisition.