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Realized 99% of all my chargers are USB-C. This can only mean one thing. New USB bout to drop!
(lemmy.dbzer0.com)
this post was submitted on 13 Jul 2025
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Not unless they want to go bigger. The USB-C pin pitch is too closely spaced for the lowest tier of printed circuit boards from all major board houses.
You might have some chargers get deprecated eventually because there are two major forms of smart charging. The first type is done in discrete larger steps like 5v, 9v, 15v, or 21v. But there is another type that is not well advertised publicly in hype marketing nonsense and is somewhat hit or miss if the PD controller actually has the mode. That mode is continuously adjustable.
The power drop losses from something like 5v to 3v3 requires a lot of overbuilding of components for heat dissipation. The required linear regular may only have a drop of 0.4-1.2 volts from input to stable output. Building for more of a drop is just waste heat. If the charge controller can monitor the input quality and request only the required voltage for the drop with a small safety margin, components can be made smaller and cheaper. The mode to support this in USB-C exists. I think it is called PPS if I recall correctly. A month or two back I watched someone build a little electronics bench power supply using this mode of USB-C PD.
What's this about a pin pitch? Or drop losses. It sounds interesting but I don't understand ☹️
Pin pitch means how tiny the physical pins in the connector can be spaced apart.
IR drop losses happen because a wire has resistance, it isn't a perfect conductor. 28AWG wire has about 0.22ohm/m. Given a 2 meter cable, you might expect to see 0.44ohm one-way. Current is also travelling back, so the circuit "sees" another 0.44ohm. That's a total of 0.88ohm
A wire will cause voltage drop following ohm's law. V=I/*R. So for 1A of current, you will see 0.88V lost.
Say you're trying to charge at 15W (5V 3A), your phone is only going to 'see' 2.36 volts, and 7.9W are wasted in the cable.
For a 100W device (20V, 5A), 4.4V are lost, also meaning 22W are wasted.
(For others reading this, this is a perfect followup to my comment here explaining the "why", while this is an excellent view into the "how" and picks up the bits I dropped about Ohms Law.)