dedicated charging port (USB) (DCP)

The USB interface is a serial I/O bus for connecting peripheral devices. In addition, the USB interface can also be used to charge device batteries from smartphones, cell phones or digital cameras, without the need for additional USB cables or chargers. This function, which was introduced with USB 2.0, is called USB Battery Charging( USB-BC).

When charging batteries via the USB interface, there are certain power limits to which the charging current is subject. These are 500 mA for USB 2.0. Since the charging process can take quite a long time under these conditions, the charging specifications have been standardized and two charging modes have been specified: Dedicated Charging Port( DCP) and Standard Downstream Port( SDP).

The Dedicated Charging Port (DCP) then provides 10 W of charging power with a maximum charging current of 1.8 A (average 1 A). To configure the DCP port, the two lines for data transfer are short-circuited on the USB interface, whereas they remain unchanged on the SDP port. This prevents data transfer and at the same time signals to the mobile device to be charged that the USB port can only be used for charging the batteries.