Other Parts Discussed in Thread: TPS2121
Tool/software:
Dear experts,
We're currently in the process of designing a new iteration of one of our products. The behaviour should be as follows;
- Only if a USB-PD adapter that is supplying 12V (or more than 11V) is connected, should the USB-PD adapter be the main voltage source.
- If a USB-PD adapter is connected that is supplying less than 11V (like 5V or 9V) it will also be the main voltage source as long as ...
- there's no PoE voltage (12V) present. If there is a 12V PoE present, it will only be the main voltage source as long as USB-PD is less than 11V.
The selected power supply (which can be either 12V PoE, 12V USB-PD, 9V USB-PD or 5V USB) will be used directly and is also used for the two buck-boost converters.
I've selected the TPS63070 as I don't know if the 5V USB will really be 5V or a little lower. If you have a suggestion for any other chip, I'm more than open for suggestions.
With regards to the review, I'm most interested in these two things;
- Whether the described switching logic above, is correctly implemented in the schematic.
- Whether the use of capacitors will pose any risks; we've tried to reduce the amount of components, but feel like it's a pragmatic setup.
- Also, I find it hard to calculate the soft start capacitor. What would be an appropriate value?
Best regards,
Jochem
