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USB power delivery (USB-PD)

USB interfaces can be used to charge batteries from small mobile devices such as smartphones, cell phones or digital cameras. This functionality is called USB Battery Charging( USB-BC) and is supported by the USB 2.0 and USB 3.0 versions, but only with powers of 2.5 W and 4.5 W, respectively. Higher charging powers of up to 100 W are achieved with USB Power Delivery (USB- PD).

USB Power Delivery is a specification of the USB Implementers Forum( USB-IF). The UPD protocol defines how the current and voltage are negotiated across the USB power pins. The lowest currents and voltages are always applied first.

Profiles of USB Power Delivery (USB-PD)

Profiles of USB Power Delivery (USB-PD)

In total, USB-PD distinguishes between five different Power Delivery profiles. The PD profile with the lowest power is profile 1 with a power of 10 W, or 5 V with 2 A. Like USB-BC, this profile is suitable for small mobile devices, whereby the specified PD power exceeds the BC power by double. The other profile power ratings go over 18 W, 36 W and 60 W to 100 W. The highest power values depend on the USB version and the USB connector. Thus, the power profile of 20 V and 3 A can still be transmitted via micro USB plugs, the highest power of 100 W only from USB 3.1 via the USB C plug and the corresponding USB cable.

In the USB-PD topology, there are devices that act as consumers, the so-called consumers, others that supply the energy, these are the providers, and still others that combine both functions in themselves. If energy is supplied from a provider to a consumer, then certain characteristic values such as the maximum power are negotiated in advance between the partners.

In the case of the USB-C interface, which can transmit a charging power of 15 W, variable supply voltage can be used in the power delivery function and the current intensity can be increased from 3 A at 5 V to 5 A. USB-C supports the five profiles specified by the USB Implementers Forum (USB-IF) and can transmit a power of 100 W with 20 V and 5 A in profile 5.

Englisch: USB power delivery - USB-PD
Updated at: 20.07.2017
#Words: 333
Links: universal serial bus (USB), digital, USB battery charging (USB-BC), USB 3.0, photodetector (PD)
Translations: DE

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