| Electronics > Projects, Designs, and Technical Stuff |
| How to step up 4.95V to 5V? |
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| XaviPacheco:
Hello all, Had problem with my internet connection these days and couldn't report back. I really appreciate all of the suggestions you've given. Let me clarify the whole scenario: I have retaken the project which I had dropped about two weeks ago. Actually, I shouldn't have written this post. Instead, I should go back to this one: Issue with Raspberry Power Supply where I give more details of the project. My bad for making such a mistake. In that post, it's clear that a solution is given. I know that I can supply a greater voltage and regulate it locally to the Pi. I really was looking for a possible solution before I redesign the entire project again. But I won't lose more time. Now that I have retaken the project, that's what I'll do. At this point, I didn't understand why the Pi was complaining at such little voltage drop. The IC sensing the voltage triggers at around 4.7V, so it doesn't make sense it to trigger at 4.95V. Ok, but I have new data: Measuring directly to the Pi, I get 4.4V, now makes sense. The 4.95V measure comes when I measure at the end of the cable directly WITHOUT THE PI connected. When I connect the PI, the voltage doesn't drop at the main board, but it drops at Pi's terminals. So, the PSU can't meet the PI's demand, I think. |
| wraper:
--- Quote from: XaviPacheco on October 08, 2018, 02:24:48 pm ---Measuring directly to the Pi, I get 4.4V, now makes sense. The 4.95V measure comes when I measure at the end of the cable directly WITHOUT THE PI connected. When I connect the PI, the voltage doesn't drop at the main board, but it drops at Pi's terminals. So, the PSU can't meet the PI's demand, I think. --- End quote --- Sounds like really low quality cable with hair thin conductors. Or/and junk psu. If there is like 4.7+ V at the input of Rasberry Pi (under heavy load) there shouldn't be any issue. |
| XaviPacheco:
--- Quote from: wraper on October 08, 2018, 02:32:40 pm ---Sounds like really low quality cable with hair thin conductors. Or/and junk psu. If there is like 4.7+ V at the input of Rasberry Pi (under heavy load) there shouldn't be any issue. --- End quote --- I have changed the cable. Now, I don't get losses at the cable without load. I get a big drop when I connect the Pi. I think it's that little PSU. Check the datasheet: https://www.mouser.do/datasheet/2/468/RAC20-K-1369798.pdf |
| XaviPacheco:
Update: I've changed the cable again and it works well now. Apparently, I have serious issues identifying a good cable for my application. |
| SiliconWizard:
I've found the RPi (especially the Pi2 and Pi3) to be very finicky with 5V power supplies. That can be a huge pain. This RECOM module is fine power-wise, the problem is the transient response. How long is your cable? |
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