6 ms·

I don’t agree. I found this straightforward statement: https://www.anandtech.com/show/16712/usbc-power-delivery-hits-240w-with-extended-power-range https://www

I don’t agree. I found this straightforward statement: https://www.anandtech.com/show/16712/usbc-power-delivery-hits-240w-with-extended-power-range https://www.anandtech.com/show/16712/usbc-power-delivery-hit... > USB-PD R3.1 supports three charging models: > - Fixed voltage > - Programmable power supply (PPS), and > - Adjustable voltage supply (AVS). > In the fixed voltage scheme, the Standard Power Range (SPR) mode supports 3A and 5A at 5V, 9V, 15V, and 20V. That’s about as clear as it can be, assuming AnandTech is correct. Also keep in mind the existence of PPS as another data point. I have an Anker charger sitting in front of me that offers 3.3V-11V at 5A. 5V at 5A falls squarely in that range, as long as you have an e-marked cable that can support 5A. (I have no idea if the Pi 5 supports negotiating PPS, but it would increase compatibility with chargers if it does.) I agree the Pi 5 should have included a buck converter or something, but I don’t think it’s correct to say they’re not standards compliant. It’s just not a common use of the standard.

KennyBlanken 3y ago
It's not hard to find at all. https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver... 5v3A is the limit of USB PD SPR.
- coder543 3y ago
  No, Wikipedia is looking like it's out of date or wrong. It’s not a definitive source, especially for highly technical topics like this. Here is another industry source which has a table that also says 5V at 5A: https://www.graniteriverlabs.com/en-us/technical-blog/usb-power-delivery-specification-3-1 https://www.graniteriverlabs.com/en-us/technical-blog/usb-po... In fact, using Wikipedia’s sources, I found the actual specs and here is another piece of supporting evidence for these other articles: > The Fixed PDOs Maximum Current field Shall advertise at least 3A, but May advertise up to RoundUp (PDP/Voltage) to the nearest 10mA. Requires a 5A cable if over 3A is advertised.[0] This is a footnote attached to 5V3A, indicating to me that chargers are allowed to offer more than 3A at 5V. At a minimum, the spec seems to be ambiguously written, but I’ve only spent a few minutes skimming it. Multiple industry sources (previously linked) believe that 5V@5A is within the spec, even without using PPS. [0]: “USB_PD_R3_1 V1.8 2023-04”
  - Denvercoder9 3y ago
    You're both correct, but USB Power Delivery, like so many things USB, is a total mess with different revisions, and versions of those revisions, that each extend and deprecate parts of the previous revision. I'm going to ignore the actual protocol used for negotiation here, but there have also been at least three different protocols. The first revision, rev 1.0, had six fixed power profiles: 5V/2A, 12V/1.5A, 12V/3.0A, 12V/5.0A, 20V/3.0A and 20V/5.0A. These were deprecated by rev 2.0, version 1.2, which instead introduced power rules at four fixed voltages, supporting power supplies with different output powers. The maximum supported currents by the specification were 5V/3A, 9V/3A, 15V/3A and 20V/5A. These power rules were retroactively named the Standard Power Range (SPR) in rev 3.1. That revision also added the Extended Power Range (EPR), which raised all the current limits up to 5A, but only when used with electronically marked cables. EPR also added power rules at 28V, 36V and 48V, again requiring (differently) marked cables and up to 5A. So 5V/5A is a valid option, but only when used with a USB PD rev 3.1 compatible power supply and cable. Orthogonally to the fixed power rules, rev 3.0 introduced the Programmable Power Supply, which allows a configurable voltage between 3.3V and 21V in steps of 20 mV. This was extended by rev 3.1 with voltages between 15V and 48V in steps of 100 mV, called the Adjustable Voltage Supply. As far as I'm aware this is not commonly used, and most products advertising Power Delivery support use the predefined power rules.
    - reactordev 3y ago
      The standard of evolving standard. Those looking take note, don’t rush to standardize something when the tech itself is still being tweaked and iterated on. Let it iterate, document it, but don’t put standards in place when you clearly can’t track or regulate it. You just look like that boomer who just now got their Windows 10 Upgrade CD to work. The reality is that with variable and programmable power supplies, it’s now up to the device to draw power at a balanced rate from the supply, instead of the “supply” pushing power in. Modern tech has allowed us to have supplies between 3V-48V, 500ma to 10A. All with a usbc head.
      - wkat4242 3y ago
        Not standardising gave us the myriad of charging and headphone plugs on mobile phones in the late 90s/early 2000s.

KennyBlanken 3y ago

It's not hard to find at all. https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver... 5v3A is the limit of USB PD SPR.

coder543 3y ago
No, Wikipedia is looking like it's out of date or wrong. It’s not a definitive source, especially for highly technical topics like this. Here is another industry source which has a table that also says 5V at 5A: https://www.graniteriverlabs.com/en-us/technical-blog/usb-power-delivery-specification-3-1 https://www.graniteriverlabs.com/en-us/technical-blog/usb-po... In fact, using Wikipedia’s sources, I found the actual specs and here is another piece of supporting evidence for these other articles: > The Fixed PDOs Maximum Current field Shall advertise at least 3A, but May advertise up to RoundUp (PDP/Voltage) to the nearest 10mA. Requires a 5A cable if over 3A is advertised.[0] This is a footnote attached to 5V3A, indicating to me that chargers are allowed to offer more than 3A at 5V. At a minimum, the spec seems to be ambiguously written, but I’ve only spent a few minutes skimming it. Multiple industry sources (previously linked) believe that 5V@5A is within the spec, even without using PPS. [0]: “USB_PD_R3_1 V1.8 2023-04”
- Denvercoder9 3y ago
  You're both correct, but USB Power Delivery, like so many things USB, is a total mess with different revisions, and versions of those revisions, that each extend and deprecate parts of the previous revision. I'm going to ignore the actual protocol used for negotiation here, but there have also been at least three different protocols. The first revision, rev 1.0, had six fixed power profiles: 5V/2A, 12V/1.5A, 12V/3.0A, 12V/5.0A, 20V/3.0A and 20V/5.0A. These were deprecated by rev 2.0, version 1.2, which instead introduced power rules at four fixed voltages, supporting power supplies with different output powers. The maximum supported currents by the specification were 5V/3A, 9V/3A, 15V/3A and 20V/5A. These power rules were retroactively named the Standard Power Range (SPR) in rev 3.1. That revision also added the Extended Power Range (EPR), which raised all the current limits up to 5A, but only when used with electronically marked cables. EPR also added power rules at 28V, 36V and 48V, again requiring (differently) marked cables and up to 5A. So 5V/5A is a valid option, but only when used with a USB PD rev 3.1 compatible power supply and cable. Orthogonally to the fixed power rules, rev 3.0 introduced the Programmable Power Supply, which allows a configurable voltage between 3.3V and 21V in steps of 20 mV. This was extended by rev 3.1 with voltages between 15V and 48V in steps of 100 mV, called the Adjustable Voltage Supply. As far as I'm aware this is not commonly used, and most products advertising Power Delivery support use the predefined power rules.
  - reactordev 3y ago
    The standard of evolving standard. Those looking take note, don’t rush to standardize something when the tech itself is still being tweaked and iterated on. Let it iterate, document it, but don’t put standards in place when you clearly can’t track or regulate it. You just look like that boomer who just now got their Windows 10 Upgrade CD to work. The reality is that with variable and programmable power supplies, it’s now up to the device to draw power at a balanced rate from the supply, instead of the “supply” pushing power in. Modern tech has allowed us to have supplies between 3V-48V, 500ma to 10A. All with a usbc head.
    - wkat4242 3y ago
      Not standardising gave us the myriad of charging and headphone plugs on mobile phones in the late 90s/early 2000s.