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| The EU is enforcing USB-C on portable devices |
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| tooki:
--- Quote from: Berni on June 27, 2022, 06:36:10 am ---This is easily solved by speaking some digital protocol over the wire, once it becomes a standard the semiconductor manufacturers quickly make cheep tiny single chip solutions to do this negotiation (because they know the market for this is large). So it does not add that much cost to the device and there is no licensing fee to pay for the standard. This also allows to negotiate other things than voltage, like the max current/wattage. It is not practical to make every charger output 5A at all its supported voltages. A tiny compact charger might do 5A at 5V but drop down to 2A at 20V. --- End quote --- The 1-Wire protocol has been widely used for this application for ages. I know it’s what Apple used in its MagSafe 1 and 2 chargers and I think (but am not certain) it was used in the earlier ones with the coaxial headphone plug thingies. |
| tooki:
--- Quote from: Zero999 on June 27, 2022, 06:54:03 am --- --- Quote from: Berni on June 27, 2022, 06:36:10 am ---Yep you would never want a analog feedback because if anything goes wrong with that feedback line (bad contact, short etc..) the output voltage might just fly off towards the max output voltage and kill the device. --- End quote --- That can be overcome with good design. If the analogue feedback inputs are biased to a slightly higher voltage, with high value resistors, the output voltage will drop to zero, if the feedback is disconnected. --- End quote --- But it makes no sense to employ precision analog circuitry when inexpensive digital is both more robust and more capable, e.g. capable of identifying charger model number, serial number, capabilities, etc. That allows the load to decide what to do if, for example, not enough power is available to charge the battery and run the CPU at maximum speed. It can then decide whether to prioritize charging and throttle the CPU, or drain the battery to maintain maximum performance, as well as dim the screen, etc. --- Quote from: Zero999 on June 27, 2022, 06:54:03 am ---The main issue I have with barrel connectors is the voltages aren't standardised. It's possible to plug a 12V power supply into a 5V device and fry it. --- End quote --- This is what I like about the Japanese EIAJ barrel connector family: it’s sized by voltage family. |
| Zero999:
--- Quote from: tooki on June 27, 2022, 10:27:02 am --- --- Quote from: Zero999 on June 27, 2022, 06:54:03 am --- --- Quote from: Berni on June 27, 2022, 06:36:10 am ---Yep you would never want a analog feedback because if anything goes wrong with that feedback line (bad contact, short etc..) the output voltage might just fly off towards the max output voltage and kill the device. --- End quote --- That can be overcome with good design. If the analogue feedback inputs are biased to a slightly higher voltage, with high value resistors, the output voltage will drop to zero, if the feedback is disconnected. --- End quote --- But it makes no sense to employ precision analog circuitry when inexpensive digital is both more robust and more capable, e.g. capable of identifying charger model number, serial number, capabilities, etc. That allows the load to decide what to do if, for example, not enough power is available to charge the battery and run the CPU at maximum speed. It can then decide whether to prioritize charging and throttle the CPU, or drain the battery to maintain maximum performance, as well as dim the screen, etc. --- End quote --- I didn't say that analogue sensing should be done, just that reliability is not a reason for not doing it. --- Quote --- --- Quote from: Zero999 on June 27, 2022, 06:54:03 am ---The main issue I have with barrel connectors is the voltages aren't standardised. It's possible to plug a 12V power supply into a 5V device and fry it. --- End quote --- This is what I like about the Japanese EIAJ barrel connector family: it’s sized by voltage family. --- End quote --- That's news to me. I have a box full of power supplies, some with the same barrel connectors and different voltages/polarities. |
| tooki:
--- Quote from: Zero999 on June 27, 2022, 10:47:47 am --- --- Quote --- --- Quote from: Zero999 on June 27, 2022, 06:54:03 am ---The main issue I have with barrel connectors is the voltages aren't standardised. It's possible to plug a 12V power supply into a 5V device and fry it. --- End quote --- This is what I like about the Japanese EIAJ barrel connector family: it’s sized by voltage family. --- End quote --- That's news to me. I have a box full of power supplies, some with the same barrel connectors and different voltages/polarities. --- End quote --- Yep, take a look: https://en.wikipedia.org/wiki/EIAJ_connector It’s not perfect, but it’s better than the complete free-for-all that the 5.5mm barrel jacks are. |
| Berni:
--- Quote from: tooki on June 27, 2022, 07:53:41 am ---That maybe would have mattered in the past, but wired syncing has almost entirely gone the way of the dodo. (In addition to iCloud, which works very well, iPhones have supported local syncing to your computer via Wi-Fi for a long time now.) --- End quote --- Yep people more rarely transfer large files over USB to a phone these days. Where it gets useful is for docks that might need to do more than that. We already got to a point where tablets are becoming laptop replacements for some people. So that port then gets a different role. It connects to a docking station that gives you an extra monitor, wired ethernet, extra USB ports etc.. This is a job that USB-C was made for but Lightning just can't do. This is also likely the reason why the latest iPads dropped Lightning. --- Quote from: tooki on June 27, 2022, 10:27:02 am ---But it makes no sense to employ precision analog circuitry when inexpensive digital is both more robust and more capable, e.g. capable of identifying charger model number, serial number, capabilities, etc. That allows the load to decide what to do if, for example, not enough power is available to charge the battery and run the CPU at maximum speed. It can then decide whether to prioritize charging and throttle the CPU, or drain the battery to maintain maximum performance, as well as dim the screen, etc. --- End quote --- Yep these days digital is just easier to do, we can stuff it all into a chip anyway once there is market volume for it. We do need to also communicate the amperage rating of the charger anyway so might as well pack all that information into a single binary stream over a single wire. Also analog might be tricked by weird resistances inside a dirty/wet connector. Digital will not, it either identifies correctly or doesn't at all. EDIT: Oh and if we went to barrel jacks then we would have the problem with "Hey Bob can you lend me that 20V fast charge cable for your laptop, i need to charge my phone." Bob: "Oh no sorry my laptop uses the smaller 12V connector" |
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