USB PD switch voltage process

[DeXi_1316761]

Hi All,

        When the Source device switch voltage from 5V to 9V, must the VBus voltage be continuous in the switching process?

        Could I turn off the vbus output firstly (5V to 0V) , then start the vbus output(0V to 9V)?  If this is feasible, how long is the limit about the switching time?

[ShifangZ_26 · Accepted solution]

Hello ,

The answer is no, the power source shall not power off and then power up the VBUS, since the power sink device have huge risk to detach report on CC line.

Please kindly refer PD SPEC of power source transition. The time shall be within 275ms if the power sink is not VBUS powered only device. If the device is VBUS powered device, you cannot let VBUS down to 4.75V.

Best Regards,

Lisa