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| would it be possible design any psu without any electrolytic capacitors? |
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| richard.cs:
--- Quote from: dmills on February 27, 2020, 12:57:47 am ---Got to admit, I don't really get the hate on for elcos, a good quality part derated suitably for temperature and ripple will go a good 20 years or so if you derate with that intention in mind, just got to do the sums and them make sure purchasing don't screw you over. --- End quote --- Sometimes 20 years isn't enough. Actually after quite a bit of research we failed to find any electrolytic manufacturers that would guarantee them to work beyond 15 years at any temperature - it was the longest they were confident the seals would last for. There are some ludicrously expensive electrolytics with glass to metal seals but they're not affordable for most applications (I've never actually seen one but they're in the digikey catalogue). As a result we've done a number of completely electrolytic-free designs for a particular customer, with an expected minimum service life of 35 years. These are mostly in the 150 W region and tend to use quite a lot of expensive ceramics, high operating frequencies and oversized magnetics compared to common designs. |
| T3sl4co1l:
Sure. What's your size and cost budget? When you see the alternatives, you may rethink your perspective on electrolytics. :) Tim |
| NiHaoMike:
--- Quote from: Psi on February 27, 2020, 11:06:54 am ---- China has started using rechargeable lipo cells in disposable products because they are cheaper than primary cells sometimes. --- End quote --- More like they found something better to do with the rejects rather than recycling them or using them to scam unaware buyers. |
| tom66:
Absolutely. But the 50Hz AC is a problem. It depends on what you are powering. Many cheap LED lamps don't use a capacitor on the 400V side, because the 100Hz lamp flicker is acceptable (if potentially annoying). Many electric vehicle chargers now do not provide a constant current output to the vehicle battery. It is modulated with the AC mains, which reduces the power factor circuit requirements as well. |
| jesuscf:
Once I saw a 7500VDC @ 20kW power supply built with a three phase rectifier (made of many smallish diodes connected in series and parallel). It didn't have any capacitors. |
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