| ID: | 4375 |
| From: | N <ni...@gmail.com> |
| Date: | Sat, 19 Sep 2020 11:11:05 +0200 |
| Subject: | Re: [pcb-rnd] upcoming change: show/enforce DRC clearance |
| in-reply-to: | 4368 from ge...@igor2.repo.hu |
> ... > 2. Why these don't work with the new setup > > The new DRC system is way more flexible than simply having a global > "Minimum copper spacing" value. The stock DRC rules distributed with > pcb-rnd releases emulate the old behavior, but the system is capable of > much more: you can easily load extra drc rules doing extra checks based on > whatever properties. For example we recently got a feature request for per > network clearance checks in DRC. And we had a feature request that got > implemented as a DRC script for zone based clearance: > > http://repo.hu/cgi-bin/pool.cgi?cmd=show&node=drc_zone_clr Feel I need to add a note about zones in the link above for power supply in abstract. Use word distance to avoid confusion between clearance/creepage. Background for power electronics, power supplies: Voltage difference between gate and source is usually small, not much above 20 volt at most so default global distance is usually OK. Voltage difference between drain and source may however be much higher, up to at least around 550V is common for three phase voltages, here a larger distance is needed. Between high voltage and protective earth or other logic conductors an even larger distance is needed to fulfill safety requirments. For these cases it it is very useful to set distance between nets used in DRC. I also expect to be useful for transmission lines in radio circuits. In some cases copper thickness is different for different layers and in this case different default distances, actually a minimum distance for different layers is useful. Except these three cases I do not know about other situations there where is a need for different distances. Regards Nicklas Karlsson
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4375 Re: [pcb-rnd] upcoming change: show/enforce DRC clearance from N <ni...@gmail.com>