Other Parts Discussed in Thread: TPS2121, , TPS2065
Hi
I'm designing a USB host product (one port), with up to 1A available at the USB host port (self powered).
My design is powered from a USB-C port, or DC IN 9V.
I use a TPS2121 as a mux between USB-C and DC-IN.
My MCU controls a TPS2065D power distribution switch to the host connector.
I'm observing large voltage drop during USB cable insertion on the host connector.
The pink plot is the 5V from USB-C power source
The yellow plot is the 5V output from TPS2121
The blue plot is the output of TPS2065D
I'm able to reduce a bit those voltage drops, especially before the TPS2065D, by increasing capacitors at the output of the TPS2121.
Plots are shown with 2 x 22uF + 10uF at the output of the TPS2121, and 22uF at the output of the TPS2065D.
What should I do to reduce this voltage drop at the output of the TPS2065D ?
I read a lot but I'm confused, adding more capacitor will help for sure but I'm missing space on the board to use larger capacitors.
Could a TVS diode on VBUS help to prevent this drop ?
Any other tip or idea ?
Thanks
