These chargers/power supplies show multiple voltages such as 5v or 9v. How do they supply both? Different pins, or do the power sinks/devices to be charged negotiate a voltage or ??

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These chargers/power supplies show multiple voltages such as 5v or 9v. How do they supply both? Different pins, or do the power sinks/devices to be charged negotiate a voltage or ??

All of these power sources seem to "charge" any device expecting a USB charger whether lightning, USB-C/Thunderbolt, or usb-mini/micro. Just some need to be left off for a while to charge.

So, thus my question.

Posted on Oct 19, 2021 5:40 AM

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LotusPilot

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Oct 19, 2021 6:01 AM in response to clherv

Power Adapters that support USB PD (Power Delivery) are more than just simple fixed-voltage power supplies.

When a device that supports USB PD is connected to a compatible Power Adapter, the device (load) actively communicates with the Power Adapter (source) over USB. The load communicates its power needs and the Power Adapter advertises its capabilities; this data exchange allows devices to negotiate their charging requirements - and it is this that determines the voltage and current supplied to the load.

USB PD uses 5V (default for non USB PD capable loads), 9V, 12V - and for some 28V, 36V, 48V and intermediate voltages.

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These chargers/power supplies show multiple voltages such as 5v or 9v. How do they supply both? Different pins, or do the power sinks/devices to be charged negotiate a voltage or ??

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