USB-C Sink Rev. 1 End User Manual
- Kenny Na
Introduction
The USB-C Sink Rev. 1 board is a USB-C to XT30 adapter designed to deliver up to 100W (20V 5A) of power to a drone (or any other XT30-powered device) during stationary debugging and testing.
For more on design decisions, see the EE documentation at USB-C Sink Rev. 1.
Core Functions
Simply connect the USB-C port to a source and have power output through the XT30.
There are multiple board variants that arbitrate different voltage values. Check the silkscreen at the back of the board to view which voltage has been configured (circled with a marker).
The 20V, 15V and 12V boards are configured with a minimum of 3A and maximum of 5A current. This means that your source (wall power adapter) needs to be able to deliver the voltage selected on the silkscreen and a minimum of 3A current.
This information is likely visible in fine print on the adapter (your source).
The 9V board is configured with a minimum of 2A, and a maximum of 5A current. This means as low as an 18W power adapter (commonly shipped with smartphones) can work with this board.
The 5V board will do as much current as your source allows in non-PD mode (up to 3A).
IMPORTANT: By default, all of the boards will briefly (very quickly) do 5V until PD arbitration is complete, due to the chip’s dead battery mode. If your use case must avoid undervolting, first connect the USB-C Sink device to the source, and then connect your device with the XT30.
IMPORTANT: If the Red LED turns on, the device will still attempt to deliver the highest voltage possible from the source.
LEDs
To summarize the LED notes in the schematic:
When the Green LED is ON, the sink device is functioning and is conducting power to the connector.
When the Red LED is ON, the sink device has failed to negotiate a USB PD contract with the PD-compatible source device.
The source device is unable to fulfill the voltage and/or current requirements of the USB-C Sink. This LED will not turn on when the source is not designed for USB-PD.
When the Blue LED is ON, the USB-C connector has been flipped (and is therefore using the CC2 pin for arbitration).
This is does not affect the functionality of the device.
I2C Test Points
The TPS25730 can provide debug and diagnostic information through the interface.
NOTE: The arbitrated voltage of the device is NOT configurable over I2C.
There is a chance that the pull-up resistors for the bus have not been placed during assembly (DNPed). Please verify that they have been soldered before attempting to use the I2C bus.
Schematic
Resources