Link to full res: https://i.ibb.co/zT2vfT56/powermanagement.png

I'm using a charger that can function in reverse to boost from battery to 5V.

The device must function without battery attached, in which case 3.3V buck/boost needs to run off VBUS. If both battery and USB source are connected, then the battery should charge and the 3.3V buck/boost should run off VBUS, not from battery. When only a battery is attached then the 3.3V buck/boost should run off battery. When battery and a USB sink are connected, then the battery charger should run in boost mode and supply VBUS with 5V, but the 3.3V buck/boost should still run off battery, not from off VBUS.

During cold boot, before there is power on the 3.3V rail, the power mux should be in diode mode due to the pull-downs on MODE and PR1, in this mode it simply prioritizes the higher voltage source, so 3.3V buck/boost will be supplied.

Once MCU has booted (not in the schematic), I check the CC channel configuration.

If neither USB source nor sink is detected I pull MODE high and leave PR1 low to set Battery as supply for 3.3V Buck/Boost (VBUS rail is unpowered).

If USB source is detected I pull both MODE and PR1 high to set VBUS as supply for 3.3V Buck/Boost, and I enable charge mode in the battery charger (VBUS is at 5V supplied from external source, BAT+ is at 4.2V from charger)

If USB sink is detected I pull MODE high and PR1 low to set Battery as supply for 3.3V Buck/Boost, and I set the battery charger into boost mode (VBUS is at 5V supplied from the battery charger, BAT+ is at 2.6~4.2V from battery) (**I need the complex logic with the comparator and the 2:1 multiplexer so that in this configuration the 3.3V buck/boost isn't powered from the VBUS line even though it is at 5V**)

Is the logic sane? Is the implementation correct? This gave me some headache, feedback apprectiated 🙏🏻

Battery charger/5V booster: https://doc.awinic.com/doc/202311/e1bf1d63-1a92-4bd2-9043-6357d7e236de.pdf

3.3V buck/boost: https://www.richtek.com/assets/product_file/RT6154A=RT6154B/DS6154AB-05.pdf

Power Mux: https://www.ti.com/lit/ds/symlink/tps2117.pdf?ts=1777634326029&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS2117

Comparator: https://www.ti.com/lit/ds/slvsdm5/slvsdm5.pdf

2:1 multiplexer: https://www.broadchip.com/Public/Uploads/uploadfile/files/20250303/BCT4157.pdf

Less important:

USB-C configuration channel controller: https://www.alldatasheet.com/datasheet-pdf/view/1140660/WILLSEMI/WUSB3801.html

GPIO Expander: https://www.onsemi.com/download/data-sheet/pdf/fxl6408-d.pdf

Thank you!



[Review request] Please help me sanity check my Battery charging / USB-OTG powering scheme