DRC and netclasses : "potential classes"
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
KiCad |
Fix Released
|
Unknown
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Bug Description
Flexible automatic design rules would need "differential net classes" that means different rules for a net depending on surrounding nets.
As an example I'll explain the problem of a traditional power electronics half bridge circuit:
HV---- [400V 10A]
|
Gh--|< [0-415V 1A] [0 < V(Gh)-V(Sh) < 15]
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Sh-------> Out [0-400V 10A]
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Gl--|< [0-15V 1A]
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GND------> [0V 10A]
HV net needs "power" class clearance and width towards all nets as does Out. Sh needs "power" class clearance towards all nets, but Gh and width according to "control" class. Gh needs the same, but "control" clearance towards Sh. Gl needs "control" class clearance and width.
Curently this system is unrealisable using KiCad DRC. I propose adding a "potential class" description to net class design rules to address this problem. Needed data stuctures for file format support and implementation need to be discussed and designed. Interested parties are encouraged to comment here and aim for a production ready blueprint.
description: | updated |
description: | updated |
description: | updated |
tags: |
added: drc pcbnew removed: kicad6 |
Changed in kicad: | |
importance: | Wishlist → Unknown |
status: | Expired → Fix Released |
Yep, this is needed for the DRC to work for higher-voltage designs.
You would also need to be able to specify a clearance that is depending on if the net is on the surface layer or an internal layer.
In practice you can typically have half the clearance on an inner layer vs an outer one.
You can also consider a simpler case where one wants to measure a high voltage net via a number of series connected smd
resistors. Since each resistor only have a part of the clearance needed you need many in series, and to pass a correct DRC you need to be able to specify the clearance to the nets between the resistors.