Hi, I want to use STUSB4500 chip to design USB-type-c interface, In the STEVAL-ISC005V1 evaluation board, I am confused about the functions of D14, R1, and R4. Can you help me? Best regard!

[GLIU.21]

The attachment is the schematic diagram of the STEVAL-ISC005V1 evaluation board.

[Winfred LU · Accepted solution]

They would be the VBUS discharge circuit.

When VBUS is charging up, D4 switches ON and charges the capacitor in a very short time.

The fluctuations in VBUS will be filtered by the C4 and R1.

The voltage is monitored with R4.

During there is a significant drop in the VBUS (cable disconnection, power down transitions, hard reset and error recovery state), the VBUS discharge path is activated on the VBUS_VS_DISC pin.