It’s no surprise that NVIDIA is gradually dropping support for older videocards, with the Pascal (GTX 10xx) GPUs most recently getting axed. What’s more surprising is the terrible way t…
You don’t just double the current you send over USB and expect cable manufacturers to adapt
That’s pretty much how we got to the point where USB is the universal charging standard: by progressively pushing the allowed current from the initially standardized 100 mA all the way to 5 A of today. A few of those pushes were just manufacturers winging it and pushing/pulling significantly more current than what was standardized, assuming the other side will adapt.
The default standard power limit is still the same as it ever was on each USB version. There’s negotiation that needs to happen to tell the device how much power is allowed, and if you go over, I think over current protection is part of the USB spec for safety reasons. There’s a bunch of different protocols, but USB always starts at 5V, and 0.1A for USB 2.0, and devices need to negotiate for more. (0.15A I think for USB 3.0 which has more conductors)
As an example, USB 2.0 can signal a charging port (5V / 1.5A max) by putting a 200 ohm resistor across the data pins.
The default standard power limit is still the same as it ever was on each USB version
Nah, the default power limit started with 100 mA or 500 mA for “high power devices”. There are very few devices out there today that limit the current to that amount.
It all begun with non-spec host ports which just pushed however much current the circuitry could muster, rather than just the required 500 mA. Some had a proprietary way to signal just how much they’re willing to push (this is why iPhones used to be very fussy about the charger you plug them in to), but most cheapy ones didn’t. Then all the device manufacturers started pulling as much current as the host would provide, rather than limiting to 500 mA. USB-BC was mostly an attempt to standardize some of the existing usage, and USB-PD came much later.
I don’t generally disagree, but
That’s pretty much how we got to the point where USB is the universal charging standard: by progressively pushing the allowed current from the initially standardized 100 mA all the way to 5 A of today. A few of those pushes were just manufacturers winging it and pushing/pulling significantly more current than what was standardized, assuming the other side will adapt.
The default standard power limit is still the same as it ever was on each USB version. There’s negotiation that needs to happen to tell the device how much power is allowed, and if you go over, I think over current protection is part of the USB spec for safety reasons. There’s a bunch of different protocols, but USB always starts at 5V, and 0.1A for USB 2.0, and devices need to negotiate for more. (0.15A I think for USB 3.0 which has more conductors)
As an example, USB 2.0 can signal a charging port (5V / 1.5A max) by putting a 200 ohm resistor across the data pins.
Nah, the default power limit started with 100 mA or 500 mA for “high power devices”. There are very few devices out there today that limit the current to that amount.
It all begun with non-spec host ports which just pushed however much current the circuitry could muster, rather than just the required 500 mA. Some had a proprietary way to signal just how much they’re willing to push (this is why iPhones used to be very fussy about the charger you plug them in to), but most cheapy ones didn’t. Then all the device manufacturers started pulling as much current as the host would provide, rather than limiting to 500 mA. USB-BC was mostly an attempt to standardize some of the existing usage, and USB-PD came much later.