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The EU is enforcing USB-C on portable devices

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PlainName:
From an out of date USB spec:


--- Quote ---In USB Power Delivery, pairs of directly Attached ports negotiate voltage, current and/or direction of power flow over
the USB cable, using VBUS or the CC wire as the communications channel.  The mechanisms used, operate
independently of other USB methods used to negotiate power.  USB Type-C connectors can support the CC wire as the
communications channel and in addition can support VBUS communication but not concurrently.  USB Type-A and USB
Type-B connectors can only support VBUS communication.
--- End quote ---
Revision:   2.0
Version:    1.3
Release date:  12 January 2017

Tomorokoshi:
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.

What does this mean for EMC testing?

SiliconWizard:

--- 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.

--- End quote ---

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?

--- End quote ---

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.

NiHaoMike:

--- Quote from: SiliconWizard on June 12, 2022, 06:40:02 pm ---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.

--- End quote ---
So it would be OK for them to use one of those audiofool linear USB supplies with over the top filtering to get unreasonably good EMI test results?

tooki:

--- Quote from: Monkeh on June 12, 2022, 10:14:13 am ---
--- Quote from: Someone on June 12, 2022, 07:20:30 am ---....because USB-C is the only connector which the PD negotiation works on (it has some extra pins to help).
--- End quote ---

I haven't checked whether the current versions support this, but the original version of USB-PD was negotiated over Vbus, and therefore worked with standard USB-A plugs.

--- End quote ---
Nope. You’re probably thinking of the USB BC (battery charging) standard, which does work on type A/B connectors. But USB-PD (which is a separate standard) is USB-C only.

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