General > General Technical Chat
The EU is enforcing USB-C on portable devices
JPortici:
--- Quote from: Zero999 on June 16, 2022, 08:27:54 am ---It took awhile for USB to become widespread on phones. That isn't an argument for government legislation. The market got there in the end, even if it did take awhile.
--- End quote ---
It just needed to be mandated from the EU in the late 2000s (i don't want to bother looking for the article again.)
Simon:
--- Quote from: Tomorokoshi on June 14, 2022, 11:51:20 pm ---
--- Quote from: Miyuki on June 14, 2022, 05:30:33 pm ---
--- Quote from: Simon on June 14, 2022, 12:20:49 pm ---I was reffering to the compatibility of the phone and power supply and the phones ability to meet the regulations every time with any USB brick supply, if the USB power supply fails in it's own right then that is nothing to do with the phone. So any properly designed phone will pass EMC regs will pass with any properly designed USB brick. So having to supply a USB brick to meet regs is no excuse for making you buy a USB brick with the phone.
Last time I was in an EMC chamber the first words out of the mouth of the test engineer after we turned it on was: is it on?
--- End quote ---
It should be two separate devices.
Isn't it one of the original purposes of EMC to "guarantee" you can plug the device into the socket, and any phone into any charger?
But you test every device separately
I expect there is some reference USB PD against it phones are tested the same way as is standardized mains for testing
--- End quote ---
I bolded the relevant statements.
First, as opposed to the specifics of phones, consider the general case of any appliance with any appropriate generic power supply.
There are a few cases we can discuss:
1. A specific appliance provided with a specific power supply.
2. A specific appliance provided without a power supply.
3. A power supply tested as a separate product.
Case 1:
A system of some kind is designed and specified. The power supply is chosen for various reasons such as cost, availability, power, EMC levels, other standards, etc. The rest of the system is designed to whatever function it provides. The combination system is tested at an accredited EMC lab. The power supply and the appliance are electrically coupled, and appropriate tests are performed.
Case 2:
A system of some kind is designed and specified. The power supply is left out of the provided system for various reasons. Cost, etc. The system must be powered to operate, so a power supply is used. To the extent possible, the power supply is left out of the EMC tests. Therefore, other variations of the EMC test procedure are used. For instance, in Case 1 the LISN connects to the AC lines of the AC-powered power supply. In this case, the LISN connects to the DC lines between the two. This is a very different EMC situation, typically requiring additional filtering on the DC input of the appliance.
Case 3:
A power supply is designed for generic applications. It is EMC tested with some type of load. However, obviously not all combinations of loads can be tested. For instance, consider that the power supply has a switcher at some frequency. The load may be other switchers and any range of frequencies and draw characteristics, some of which may cause the power supply to have EMC problems that weren't found in the EMC lab.
Simon's statement fails at the term "properly". What defines that? In Europe, it's basically the CE mark. This doesn't mean some particular combination will pass.
Miyuki's statement fails at the term "guarantee". The EMC standards are meant to prevent one system from interfering with another. These systems could be two internal parts, which is where the system test comes in, or two independent systems, which is the purpose of both emissions and immunity testing. In the case of plugging in the power supply, the test is done to some generic loads. However, the specific load of the appliance may be out of the range that a specific power supply was tested to.
In general I have two takeaways:
1. It's a nice idea. There will be unintended consequences.
2. Is this really the biggest issue that could be addressed with e-waste?
--- End quote ---
I'll try to make it even simpler. Radiated emissions failures are of the device under test. If the phone passes radiated it has passed. It also needs to pass conducted. This is easily done if the phone circuitry that let's face it is a 5V/3.7V DC/DC. If that passes it has passed. The reason it passed was that there was enough filtering and capacitance in the power input to not draw power in spikes at some frequency but to draw power "as DC". If you are drawing power smoothly then as long as the power brick you plug into meets requirements you should be fine, there should not be any interaction. The power brick in turn will have enough output capacitance that some spiky current draw should not have adverse effects on the regulation or send it into some weird frenzy of radiated or conducted emissions.
If the power brick is shit and the combination of power brick and compliant phone fail, that has nothing to do with the phone manufacturer and they don't have to give a toss or supply a brick just in case. As far as I am aware there are no widespread cases of people having issues.
PlainName:
--- Quote ---As far as I am aware there are no widespread cases of people having issues.
--- End quote ---
Actually no widespread cases of people reporting issues, which is somewhat different.
A common issue with USB power supplies is screwing up of touch screens. My bulk supply, which I used to think was pretty damn good, does this - a phone plugged in doesn't respond to touch properly, although I never actually noticed since it was hard to use the phone with a short cable so I always unplugged to use. But a Garmin SatNav was the same, and bad enough that I was on the verge of returning it as complete shit before I realised it was the PSU.
Apparently that PSU isn't a unique one-off. Another one would screw up my scope when it powered the lights over the bench, regardless of what I was probing or how. Took a while to track that one down as well, and I'm supposed to know about this kind of thing, so what's your average non-techy user supposed to notice?
I might also refer you to Powerline adapters, which really annoy RF fans but no-one else notices - another case where lack of reports doesn't mean lack of an issue.
Simon:
Have any of these adapters been properly EMC tested? I don't know what the standards would have done but I would hope you put a range of loads on the adapter. If they are passing tests but causing an issue well then legally everyone is in the clear and the legislators need to go and have another think about how to deal with it.
PlainName:
I have no idea! They are, of course, made in China so any CE mark would be suspect even if it existed :)
However, I don't think that's relevant - the point was that these are examples of problems that don't result in mass complaints, so the lack of complaints can't be taken as an indicator of no issues.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version