Circuit will have 2 power options:

•     CR2025 coin battery
•     USB-C 5V@3A

USB-C socket CC lines are connected to ground via 5.1K ohm resistor. This tells power source to supply 5V on VBUS line. Most ICs I chose have maximum supply voltage of 6V.

The circuit will have a small on-board LED for SOS signal output. Additionally, a high-side PMOS load switch can be connected to a larger load, such as a 12V lamp. An external power supply with a maximum of 40V will be needed for this.