TPS25830A-Q1: There is no VBUS output after C to A hot swap.

Hi Alan,

This is unexpected behavior.  I would expect that with the cable attached, then power on, VBUS should be stable at 5V.  When a device connects to the Type-A port, VBUS should remain stable as long as there isn't an overcurrent condition.  Can you confirm only one of the CC pins has the 5.1k pull down?

Can you explain what you mean by "hot-swap handshake recognition"?

Thanks,
Eric

Hi Eric，

Attached is the waveform of USB CC1 and CC2 cold start and hot plug test. Please help me find out why hot plug does not work. Attached is the customer's waveform test and schematic diagram, please help take a look.

USB CC 测试.docx、

Eric Hartigan said:

Can you explain what you mean by "hot-swap handshake recognition"?

Hot plugging means that after the initial power-on handshake, VBUS outputs 5V, plug and unplug the C to A cable, and then find that VBUS cannot output 5V.
Hot plugging means plugging and unplugging the cable when the USB CHARGER is working normally, and plugging and unplugging with VBUS powered on is called hot plugging.

Hi Alan,

Can you upload a higher resolution schematic?  I can't read the current version.  I am also reuploading the .docx in English for future reference.

In the schematic, there appears to be a resistor placed from CC1 to GND.  If so, this will interfere with the 5.1k in the C to A cable used for cable detection.

/cfs-file/__key/communityserver-discussions-components-files/196/USB-CC_5F00_English.docx

Regards,
Eric

Hi Eric，

The pull-down resistor of CC1 is not attached.

Eric Hartigan said:

In the schematic, there appears to be a resistor placed from CC1 to GND.  If so, this will interfere with the 5.1k in the C to A cable used for cable

奔腾E541(B7401)_MB_V1.0_20241018.pdf