I have a device that can take power in from two USB ports. I want to make sure that when the USB2 is plugged in, the USB1 Power gets disconnected. I have come up with the following schematic design for this purpose.

  1. When USB2 is plugged in, the PMOS turns off and USB1 power disconnects
  2. When USB2 is not plugged in, the PMOS turns on and USB1 power connects
  3. When both USB1 and USB2 are connected, only USB2 sources power but USB1 can be used for communication only

Am I doing it right?

On side note,

a. The Schottky Power Rectifier has a forward voltage of 0.375 and 0.4V. Are there ways to get rid of the diodes and place a transistor instead? b. The PMOS has a minimum required Vgs of -0.4V. What does the negative symbol means?

Thank you

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