Toz, nech to mame z krku na dnes, "ty debile to prece vi kazdy, takovou banalni vec, ses totalni debil". Kedze jediny perspektivny USB konektor je USB-C, tak bacha na to, ze USB-C nabijacka nedava vonku ani prd, narozdiel od starsich s USB-A koncovkou kde tych 5V 500mA bolo vzdy. V celom to standarte je uplny mrdnik a protichodne tvrdenia, toto som nasiel na digikey fore a je to spravne - vyskusane. Tak keby ste davali USB-C konektor ako napajanie zariadenia treba mat na pamati toto:
The DFP advertises its VBUS current capability by varying the pull-up on its CC pins:
5V 3A capability is advertised by sourcing 330 μA (±8%) into each CC pin (e.g. using 10 kΩ pullup to 5V or 4.7 kΩ pullup to 3.3V)
5V 1.5A capability is advertised by sourcing 180 μA (±8%) into each CC pin (e.g. using 22 kΩ pullup to 5V or 12 kΩ pullup to 3.3V)
“Default USB Power” is advertised by sourcing 80 μA (±20%) into CC (e.g. using 56 kΩ pullup to 5V or 36 kΩ pullup to 3.3V)
Default USB Power means:
If you connect as USB device then the rules of the applicable USB specification must be followed.
If a charger is detected using the D+/D- lines as per the USB Battery Charging 1.2 standard then you may draw up to 1.5 A but the voltage may drop as a result, see that spec for details. This allows for detecting non-Type-C chargers, although Type-C chargers are also still required to support this.
Otherwise, you may draw up 500 mA from VBUS.
To determine the current advertised by the DFP you measure the voltage on the CC pin (i.e. across the 5.1kΩ resistor):
below 0.20V means no source is connected
between 0.20V and 0.66V means you’re limited to Default USB power as described above.
between 0.66V and 1.23V means you’re allowed to draw up to 1.5A
above 1.23V means you’re allowed to draw up to 3A
Cokolvek ine, ako pisu vyzaduje PD chip, ktory pokeca so sourcom, napr. ten Cypress, ktory je standalone bez mCU schopny vyjednat tych 20V 5A alebo oblubeny ST, ktory je uz dlhu dobu vypredany.