Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Comments on Does My Circuit Contain High-Speed Signals?

Post

Does My Circuit Contain High-Speed Signals?

+2
−0

My circuit includes the following components:

PIC16 with internal clock, frequency: 32 MHz

ST LED2000 LED driver (a buck converter) with a PWM dimming input

TI BQ24070RHL battery charger

LED controlled via PWM by the microcontroller.

My question:

Do the following signals qualify as high-speed?

I’m asking this to determine whether I need to ensure a proper return path for them and/or maintain large spacing between them. If not, can I ignore the return path considerations?

Key signals I believe require attention:

  1. Charger outputs – These are open-drain outputs. These outputs are connected to the microcontroller inputs (with internal PU). I couldn't find rise/fall time specifications in the datasheet.
  2. PWM outputs from the microcontroller – Base frequency: 200–500 Hz.

One output goes to the LED driver (possibly with or without a pull-down resistor).

Another output drives an LED.

  1. Push button with a pull-down resistor, connected to a microcontroller input.
History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

2 comment threads

EMC (2 comments)
You are asking for a spot of design review. That's fine. (2 comments)
EMC
Lundin‭ wrote about 12 hours ago

In case you are asking this for EMC purposes, the return path isn't as much a concern as sharp edges from the oscillator/PWM/LED driver etc causing radiated emissions. You can still get crosstalk and similar at modest frequencies, but that can be avoided by common PCB layout best practices. It all depends on what EMC requirements you have on the product.

Eyal78‭ wrote about 6 hours ago

In this project, there are no formal regulatory or compliance requirements. However, I want to design the board the "right" way—not just to make it work properly, of course.

I'm trying to determine whether I should take all the considerations I've described into account or if this is a relatively simple board, allowing me to disregard some of them. For example, could the board be designed with just two layers? After all, a two-layer board isn’t necessarily a bad choice.