Hi
I’m trying to use the USB-C Power Delivery Board to power a mobile camera system. I want to include a power switch in the circuit powered by the power delivery board, to turn the system on and off. Problem is that this causes the output voltage to drop to zero. Most times the PDO3 light turns off but sometimes it will remain on even though there is no output voltage anymore. When everything is switched on before connecting the USB-C cable to the power delivery board everything works as expected. But using the power switch when the power delivery board is already connected fails.
In the product video it is mentioned that measuring the output voltage can lead to the board turning off due to a change in capacitance. But this is not further explained. Could you explain the reason for this behaviour and how I can avoid it?
Thanks in advance!
That is due to how the current and voltage is being monitored by default on the STUSB4500 - check out our hookup guide here https://learn.sparkfun.com/tutorials/po … egotiation - especially the sections from “USB-C Power Negotiation” and the ones that follow…the voltage ranges being utilized can be altered to suit your use-case (as long as it is within the allowable range) for PDO 1-3
Also be sure to run through the Example4 - Changing Voltages on the fly.
Hope this helps!
Thanks for the quick reply.
The problem is not negotiating the voltage but rather using a physical on/off switch in the circuit powered by the power delivery board. I would have expected the power delivery board to maintain its output voltage but when switching the circuit back on the power delivery board cuts the power and needs to be reset by replugging the USB-C cable.