AVD current measurement

[gkasprow]

• remove ref diode;

• reverse Zener diode

• Rg=10k

• add R shunt = 5k6/3

Originally posted by @gkasprow in #1

[gkasprow]

nowe we have current measurement based on Zener, reference Zener

and diff amplifier

that doesn't work well.

We are interested in th ecurrent difference between PNP and NPN parts

so let's treat Zeners like overvoltage protection; add 1k8 in series and route both singnals to diff amp; get rid of R87;
R83 need to be connected to 1.2xV precision reference (some low cost reference diode like TS3431)

[filipswit]

Is this what you were thinking?

[gkasprow]

make it easier; imeas P, imeas N route to inverting opamps

we will calculate difference in digital way
you will need one extra ADC, you can use spare channels for 5V and 3.3V monitoring

[filipswit]

I can add another ADC, but does it make sens to measure P12V0 with INA and ADC? When we remove P12V0 measurement from ADC there will be room for AVD and MeasP/N

[gkasprow]

Sure lets do that