ryan-ma
Add a diode between VBus and the USB-C connector?
Hey! I love this board, but one thing that would really enable a lot of use cases is an additional diode that prevented backflow from VBus to the USB port, and a second diode that allowed current flow from the pin header back to the voltage regulator.
With that, we would have a choice of a few different operating modes with a battery connected to the IO header:
-
Q1 turned off, PD requesting a voltage above the battery voltage, running directly from USB
-
Q1 on, PD requesting constant current, battery is charging
-
No USB power, battery is powering the voltage regulator
As far as I can tell, battery charging is one of the most exciting uses for this, and it would be amazing to use the onboard voltage regulator when on battery power.
Thanks for your suggestion. I noticed this problem after the board was completed and mass produced. I am working on the next generation PD trigger. Stay tune in CrowdSupply.
Great to hear! Sounds like this device will truly be a world first in the next rev!
Many designs have back to back PFETs, joined at their Sources with a common Gate drive as a Vbus switch (rather than a single PFET). Would this stop the backflow you are concerned about?
