General > General Technical Chat
The EU is enforcing USB-C on portable devices
Someone:
--- Quote from: tooki on June 13, 2022, 11:51:23 am ---
--- Quote from: Someone on June 13, 2022, 11:08:45 am ---
--- Quote from: tooki on June 13, 2022, 10:57:49 am ---
--- Quote from: Monkeh on June 13, 2022, 04:25:54 am ---Perhaps you would share with the class rather than jabbing that it's easily found.
--- End quote ---
For me, googling "usb pd specification 1.0" brought this up on the first page of results:
https://caxapa.ru/thumbs/342141/USB_PD_V1_0-20120705-final.pdf
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Also usb-if:
https://www.usb.org/document-library/usb-power-delivery
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Right, but that’s for the current PD standard. The issue was finding V1.0, which is no longer on the USB-IF site.
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If you download/open that it does contain the legacy specifications alongside the newest details, which is why I couldn't determine if that part was still supported/current.
tooki:
I actually skimmed the 1.0 and 2.0 versions side by side last night. The 2.0 is certainly still active. It’s just not used very widely. I did find a Xiaomi charger using it, and one single USB socket on Digi-Key for it.
Simon:
--- Quote from: Miyuki on June 13, 2022, 07:07:12 pm ---
--- Quote from: Simon on June 13, 2022, 06:40:49 pm ---
--- Quote from: SiliconWizard on June 12, 2022, 06:40:02 pm ---
--- Quote from: Tomorokoshi on June 12, 2022, 03:57:41 pm ---I have an actual technical question related to this.
Consider the situation of EMC testing. When a charger ships with the product, the EMC test is done on the combination of the power supply and the product. If no power supply is shipped, the manufacturer is free to choose anything that is within the nominal specifications.
More than once in EMC testing changing the power supply resulted in the difference between passing and failing, sometimes by a quite large margin.
Therefore, it's likely that as manufacturers continue to not provide a power supply, then they will test with a top-quality "quiet" supply that give them, let's say, 10dB margin in some EMC test. If the top-quality supply sells for $20, while the cheap ones are $2, it's likely that a fair percentage of customers will get the "equivalent" cheap supply. This is already a dynamic with cell phone chargers.
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You're quite right. That's a general problem with devices supporting "compatible" hardware. There is a gray area there.
--- Quote from: Tomorokoshi on June 12, 2022, 03:57:41 pm ---What does this mean for EMC testing?
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Not sure it will change much.
If the manufacturer sells a device with a charger, then this exact combination has to be tested.
If it doesn't provide a charger, then it can use whatever off-the-shelf charger gives the best results during testing.
That's already the case for a majority of manufacturers offering charging through USB, whether it is micro-USB or USB-C.
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commercial emc is a piece of cake at these power levels, if I can get a 5V 1A to pass military standards first time then anyone making battery charger circuitry in the phone that cannot pass commercial with any supply is not fit for their job.
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There is a reason why chargers are made in Asia. EMC is just printing on the case. No company in US or EU will be allowed to manufacture and sell what they can do. This way distributor can just say it was a bad batch, or any other cheap excuse with no consequences even if something happens.
They commonly omit almost all filtering till it works somehow.
I for example have one charger so noisy when I connect it to the phone it just totally messes up the touchscreen (do this to multiple phones)
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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?
Miyuki:
--- 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?
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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
Tomorokoshi:
--- 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?
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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
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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?
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