STUSB4500 Discharge path

[Kevin1]

Hello everyone,

I have a question about the application schematic in page 24 of the datasheet STUSB4500.

I don't understand the utility of D4/C4/R1 and R4, why not use only one resistance between VBUS en VBUS_VS_Disch to discharge the bus ?

Best Regard's,

[Gregory Go.]

Hi, 

You are right, using 1 resistor can be sufficient to discharge VBUS.

The additional circuitry is used to limit the voltage drop impact during inrush current. So the schematic implementation depends on the kind of inrush current you can get in your application.

For the minimal implementation, please refer to the STUSB4500 reference design: STREF-SCS001V1

https://www.st.com/content/st_com/en/products/evaluation-tools/solution-evaluation-tools/psu-and-converter-solution-eval-boards/stref-scs001v1.html

Actually the schematic in the STUSB4500 datasheet is a copy of STUSB4500 evaluation board: STEVAL-ISC005V1

https://www.st.com/content/st_com/en/products/evaluation-tools/solution-evaluation-tools/psu-and-converter-solution-eval-boards/steval-isc005v1.html