Electronic – USB Type-C configuration necessary for battery charging only

usb

I want to utilize a USB Type-C connector to charge a single battery that powers a device. The device will only function as an upstream facing port (UFP) or sink and no data communication will need to occur using USB2.0, USB3.0/3.1, or Aux pins.
What are the minimum components necessary (besides the Rd resistors) for the CC1, CC2, and VBus lines to use a USB Type-C receptacle to charge the battery off the VBus line? Will the source side recognize complete connection and orientation and know when to send 5V through to VBus or do I need to control that on the sink side?

Best Answer

According to the spec:

A DFP must implement a Rp pull-up resistor to 5.0V or 3.3V. When a DFP to UFP connection is made, a resistor divider is formed, and the voltage at the CC pin can be measured to interpret the type of connection.

TABLE 2: CC PIN VOLTAGE RANGES

  • CC Pin Voltage
  • 0.00V - 0.25V No connection
  • 0.25V - 0.70V Legacy current (500mA for USB2.0, 900mA for USB3.0/3.1)
  • 0.70V - 1.31V 1.5A capable
  • > 1.31V 3.0A capable

If Rd=5.1k 1% then CC Vmax=2.04V

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