Hi guys !
I am trying to implement a USB-C powering and communication between 2 of my devices. There is no Power Negociation implemented yet. The default voltage is 5V.
I want to make sure my source device is safe so I would like it to shut down VBUS if VBUS > 5V + 0.6V thanks to monitoring feature of STUSB1602.
I tested the VBUS monitoring feature the following way with this typical implemental (cf fig bellow) :
- Nothing is plugged on the USB-C connector
- Start source device
- Enable Power with I2C communication
- Set nominal voltage to 5V with I2C in register 0x21 -> register value is correct and equal to default value.
- Measure VBUS voltage with multimeter -> 5V is measured
- Force 10V on VBUS -> abnormal voltage is not detected and VBUS stays at 10V
Based on my experiment, my source device does not behave as expected and cannot protect the sink device from a VBUS overvoltage. Meaning, VUS_EN_SRC stays at 0V during overvoltage condition.
Extra info :
I tried this experiment with the 0x2E register at 0b00000001 value and at 0b00000000 but the result is the same (which is expected).
Do you have any idea of what could be the reason why VBUS monitoring is not working ?
Thank you in advance for your help 🙂
