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Two more questions on Switching power supply courses

flyforward , 03-02-2016, 07:49 PM
Hi all,

I have two more questions for this courses.

First, in the beginning of lesson 6, to reset the designator, we need to type "isdesignator" in the pcb filter, apply and goto pcb inspector to uncheck the hide. However, when i go to pcb inspector, it shows as attached. I hide each component manually before. Just want to know how to do it right.

Second, in the last of lesson 5. It is taught that, layer 4 should cover the area of layer 3 (1:04:47). Why is that?

Thanks again,
robertferanec , 03-03-2016, 04:41 AM
Empty Inspector window means, that you have probably selected different kind of objects with no common parameters/properties or nothing is selected. Be sure you check "Matching -> Select" and press "Apply to All".

Could you attach the whole screen with Filter + PCB and also Inspector + PCB?

The second questions: it's good for return currents. Higher frequency return current travels under the tracks, for low frequencies it travels the shortest way - for both cases it's good to have a solid GND/PWR reference plane under all the tracks. Have a look here: https://www.maximintegrated.com/en/a...ex.mvp/id/5450

50kHz ground current, Drawing courtesy of Dr. Bruce Archambeault, source here >
flyforward , 03-03-2016, 12:15 PM
@robertferanec. Thank you very much.
For the first question, i followed your suggestions and it is yield and i did miss check "select".
For the second question, It is well explained in that tutorial. But i have a follow up question. Whether a larger ground plane can reduce the current density on the ground plane, like "diluting the current by a larger plane."?
BTW, i have another question, as shown in the attachment, the color of layer 4 (5V_VCC) should be light blue (not the one at the bottom layer, which is dark blue, i suppose), changes to a mix of light blue with many brown dots when i remove the trace and added polygon. Do you know why is that?

Thank you very much and i really appreciate your time and efforts putting into this.
robertferanec , 03-04-2016, 05:52 AM
- Ground: Maybe try to search on internet and play with some simulations to get idea how the planes will influence current flow I heard, Altium will have a new plugin (I think it's not going to be free). It is called PDN Analyzer > http://go.altium.com/pdn-analyzer-beta.html

- Layer color: I am not really sure what you mean, but when you zoom in, the color will have squares, when you zoom out, you will see the full color.
flyforward , 03-04-2016, 09:42 AM
@robertferanec Thank you very much !
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