Differential Probe Over Range Indicator Idea

[FxDev]

I am working on a DIY 1000V differential probe project.

I have completed the first stage of the circuit and its simulation. The project is essentially based on the DP10013 model from Micsig. Using the DP10007 schematic that Dave released and all the photos I could find on the internet, I set up a simulation on Proteus and observed that my circuit appears to be working. Of course, I am sure I will encounter hundreds of problems in real life

As you know, these types of devices have an over-range indicator. However, I couldn’t fully understand Micsig’s circuit for this. I will also use a microcontroller in my project, just like Micsig did. I selected the 32-pin Puya (030) as the processor.

I always think of using comparators, but generally, all high-speed comparators are single-supply and quite expensive. Micsig, on the other hand, used a simple opamp (OPA2171) in their circuit.

Do you have any suggestions on this matter?

[FxDev]

I think OPA2171 is using for zero input voltage set offset value.

They are using simple 3 resistor divider. Then it goes to ADC or Comparator of the MCU.

If it exceeds the limits (you can see blue trace) MCU is blinking the leds.

Micsig using EFM8BB51 MCU. So they are using P0.3 pins. This pin have "CMP0.P2" features. Response time is not great, around 171ns minimum. But maybe they are using ADC's for that.

Puya has comparators too. If i didnt read it wrong, it is better than EFM8.