3 ms·

Apple solves this by doing all PD negotiation in hardware.

• nyrikki 1y ago
  Unless you are very price sensitive, using USB Power Delivery ICs is the norm now for most devices, but PD is different than POE. PD is just loose tolerance resistors on USB.
  • floating-io 1y ago
    No, it's not. You can do very basic selection with resistors, but you can't get above 5V (or more than a couple of amps IIRC) without using the actual PD communication protocol.
  • p12tic 1y ago
    Incorrect. https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver... is a good start about the subject: "PD-aware devices implement a flexible power management scheme by interfacing with the power source through a bidirectional data channel and requesting a certain level of electrical power <...>".
    • nyrikki 1y ago
      You can tell I have been in the 5v world too much, thanks for the correction.