How much ripple and noise can damage a cellphone battery, components or charging - Page 1
Forum section: electronics / testgear

author: sx57
author_rank: Contributor
timestamp: October 21, 2024, 04:51:57 am
content: Hello dear members of eevblog great community.for some time, I have been testing some phone USB chargers, for example Samsung 25W original and fake ones or apple 20w and many other brands.First there was the dilemma of adding a 10uf and 0.1uf capacitor to oscilloscope probes, at the output of the charger ,point of measuring, in order to measure the noise and ripple.After some experiments and reading a lot of methods recommended to measure PSU ripple, like Intel ATX ,and some other PSU manufactures plus YouTube videos, I came to conclusion that adding caps is probably the right way. because, although not using the caps makes the test show the real output of the charger specially switching noise, but adding them actually helps me distinguish between fake and original ones .it seems that original chargers engineers take into account the filtering caps in the charging circuits of the phones. I don’t know If I am right or wrong though.For example: Samsung 25w EP-T2510 chargers, has a noise output of 640 mv peak to peak, while a fake 25w charger has 477mv, so the fake one is better in output quality! then i added the caps, original 25w chargers noise output became about 148mv while the fake one became 252 mv. As you can see now there is a huge difference between the two in favor of the original. I saw a similar pattern between some fake and original apple 20w chargers. The original performs way better with added caps.Most of the fake ones normally show worse performance of course, whether I use the caps or not but in some cases as the example just wrote, adding the caps changes the better charger. I mean some chargers specially originals, perform better when I add the capacitors to measurement point.My oscilloscope is Owon 1022(not isolated version) and though it is humble and on a budget, it is really good enough.When I have the money I will better ones.I use the small ground spring on the prob.It is on 10X to have maximum bandwidth.I use peak detect mode because it shows peak noise and ripple way better than sampling.I uploaded the pics of 25w Samsung chargers’ measurement on 1ms time base because it shows more ripple and noise than shorter time bases.The oscilloscope is connected to a laptop using only the BATTERY when measuring ripple and noise.I use multilayer caps because they are better than ceramic and electrolytic.My goal is to sell chargers and review them based on their performance. Ripple and noise are measured for this. To see what is better and what may DAMAGE the battery or the components of the phoneI now have these questions please help me understand:1-at what ripple output, RMS and PEAK TO PEAK, the charger actually starts damaging cellphone battery, components or charging circuit in the phone, if I measure with the caps added to measuring point and the probes?2- What about if I measure without any caps? What is the damaging ripple and noise voltage output with no caps at the probes?3-does the shape and frequency of the ripple or noise matter? I mean can there be for example one shape and frequency of ripple with 200mv P to P amplitude that is healthy for the phone, while another shape and frequency with the same 200mv P to P amplitude but dangerous and damaging to the phone or battery?4-in all ripple and noise measuring guides, P to P is important, does it mean RMS doesn’t really matter?5-Which method is better any way, adding caps or not?7-does adding caps simulate charging circuit filtering in the phone or it actually does something else?8-am I wrongly measuring noise and ripple? Should I change the way I do it?Sorry for so many questions.It will be very kind of you to even partially answer some of them so I know how to better evaluate the charger’s quality according to their ripple output.I uploaded 25w Samsung fake and original ripple and noise tests and pics of measuring point and probe so you may see how I performed the tests.Thanks a lot, from all of you.

author: Simon
author_rank: Unknown
timestamp: October 21, 2024, 07:41:23 am
content: Please DO NOT double post, it is disrespectful to other members and they get really annoyed, you won't be popular.