Other Parts Discussed in Thread: TPS2552
Tool/software:
Dear,
I would like to use the TPS2116 to switch between 2 5V power sources of a device that can behave both as USB host (when it has its own power supply) and as USB device (being powered from the USB port).
The purpose would be to power the 5V to 3.3V DCDC converter from the internal power supply when the device is behaving as USB HOST and from the 5V coming from the USB connector when it is behaving as USB DEVICE.
Below you can find a simplified block diagram: TPS2552 is used to provide 5V to the USB connector during USB HOST mode and limit the current
CASE1: USB HOST
5V_POWER (VIN1) is present
5V_USB (VIN2) maybe be present or not, depending if we enable TPS2552
The desired behavior in this case is that 3.3V buck is powered by 5V_POWER (in the image below in red you can see the desired power path highlighted)
CASE2: USB DEVICE
5V_POWER (VIN1) is not present (it is either 0V or floating)
5V_USB (VIN2) is present
The desired behavior in this case is that 3.3V buck is powered by 5V_USB (in the image below in red you can see the desired power path highlighted)
Questions:
1) Is there any issue for TPS2116 when VIN1 is floating and VIN2 is transitioning from 0V to 5V (USB cable is connected and decoupling capacitors are charging)?
2) Is there any issure for TPS2552 to have 5V on the OUT pin when the IN pin is at 0V/floating?
Best regards
Alessandro
