Schematic Review - Beginner Help

Hello all, I am currently in the process of designing my first board as a beginner to electronics and I need advice and direction on how to navigate this project. I’m really new to design and I would love to learn, I am looking for support and guidance!

The current schematic is incomplete (amplification for example) but the core function is laid out, I would like to know if my design is flawed. I have left my concerns below and I would greatly appreciate any more concerns.

The outputs are not meant to be complementary digital signals, but route the original analog signals to corresponding high and low.

Purpose: The comparator circuit is designed to analyze and dynamically route analog voltage signals generated by APDs (Avalanche Photodiodes) into separate high and low analog outputs. These outputs will interface directly with an FPGA, reducing the need for complex logic processing and enabling simpler signal handling.

Logic: The current design relies on the use of a comparator circuit to drive transistor logic:

  • Two APD analog voltage readings V1 and V2 are input into a comparator as non-inverted and inverted inputs respectively.
  • The comparator outputs two complementary signals, the raw output and an inverted output which serve to drive the bases of the transistors
  • The analog voltage signals are then routed into the collector of these transistor

Also note, above transistor q2a there is a mistake there should be no junction. sorry about that!

Concerns:

Simplification: Is this design an over complication of what can be done more reliably and efficiently by an available off-the-shelf integrated circuit?

  • Analog Switch
  • Multiplexer

Functionality:

  • trans-impedance amplification of APDs
  • preventing oscillation of the comparator (hysteresis)
  • preventing noise and signal loss
  • high and low voltage signals of the comparator
  • ** voltage regulation (resistance, zener diodes)
  • switching to mosfet transistors to prevent significant voltage drops rather than bjt
  • gate activation of transistors
  • ** pull up/down resistors
  • how can this design be interfaced directly with the FPGA?
  • ** converting analog signals using ADCs

I think the most likely solution to making a sound design is using analog switch IC, are there any recommended resources one can offer to learn how these function with minimal prior experience?

Thank you for taking your time to help me out, it means a lot!

We usually suggest that questions like these should be asked at EEVblog rather than here

2 Likes

my apologies, i’m new, thank you so much!

No problem.
When you have a questions regarding KiCad use (you can’t do something you want, you can’t find function you are sure there have to be, something you are doing works differently than you expect and so on…) just ask here. You have close to 100% guarantee to get fast and valuable answer.
See two threads:

These are two examples of discussions being not directly related to KiCad but having a potential to rise questions regarding to KiCad.
Your post looks like you have absolutely no problem with KiCad use but you have only electronic questions so there are better places to ask them to be seen by people more interested in electronics and not only in KiCad.

2 Likes

This topic was automatically closed 24 hours after the last reply. New replies are no longer allowed.