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Ploygons as heatsinks

autodeskguest

 

Hi, I wonder if someone can give me some pointers.

 

I'm using Eagle 5.2 light, and I want to create an area of board on the top

layer that's to be used as a heatsink area for a voltage regulator. The

regulator tab is on net POWERGND. When I create the polygon I can't get it

to connect to the tab in any way (despite changing names, net classes etc).

It always deletes parts of the polygon during the routing phase such that

tracks pass through it with the clearance specified in the design rules. How

can I get Eagle to understand that it should be connected?

 

Thanks

 

Richard

 

 

 

  • Richard Hince schrieb:

    Hi, I wonder if someone can give me some pointers.

     

    I'm using Eagle 5.2 light, and I want to create an area of board on the top

    layer that's to be used as a heatsink area for a voltage regulator. The

    regulator tab is on net POWERGND. When I create the polygon I can't get it

    to connect to the tab in any way (despite changing names, net classes etc).

    It always deletes parts of the polygon during the routing phase such that

    tracks pass through it with the clearance specified in the design rules. How

    can I get Eagle to understand that it should be connected?

     

    Thanks

     

    Richard

     

     

    If you name the poygon the same as the wanted net, there should be no

    problem. But usually a regulator like 78xx with TO220 case have an area

    in b/v-restrict layer. You may see that if you switch on those layers.

    This prevents the mounting hole (and therefore the case) connecting to

    circuits.

    To "overcome" this you can draw thick wires! to make the "connection"

    yourself which of course is disliked by the DRC image ,or you can copy

    that regulator into a new library, remove the restrict and use this new

    part instead. But be careful, you must know what you are doing.

     

    --

    Gruß

     

    Jörn