I can help design this HAT, but I can’t make schematic changes right now because this account has no available ACUs, so AI execution features are unavailable.
What’s been accomplished so far:
- The project is newly created and currently empty: no components, nets, or schematic wiring yet.
- I reviewed your requirements for a Raspberry Pi 5 UPS HAT with:
- 6–18 V barrel input
- 5 V / 3–5 A buck output for Pi 5
- 1-cell LiPo charging
- battery-backed 5 V UPS path
- 40-pin Raspberry Pi header power connections
- 4-pin I2C sensor header tied to Pi GPIO I2C pins
What remains to be done once ACUs are available:
- Select concrete ICs for the buck regulator, LiPo charger, boost/power-path stage, protection, and connectors.
- Add the Raspberry Pi 40-pin HAT header and external I2C header.
- Wire:
- 5 V UPS output to Pi pins 2 and 4
- GND to Pi pins 6/9 and system ground
- 3.3 V from Pi pin 1 to I2C VCC
- SDA to Pi pin 3
- SCL to Pi pin 5
- Add support parts: inductors, capacitors, feedback dividers, protection diode/TVS/fuse, battery connector, and pull-ups if needed.
- Run ERC/design review and produce a bring-up checklist.
Recommended architecture when work can continue:
- Use a high-current 5 V buck regulator from the 6–18 V barrel input.
- Use a dedicated 1-cell LiPo charger from the input supply.
- Use a 1-cell boost converter rated for Raspberry Pi 5 load current, with ideal-diode or power-mux behavior so the Pi stays powered when input is removed.
- Treat the Pi 5 as a high-current load: design for 5 V at 5 A if you want margin.
Once ACUs are available, I can proceed with component selection and schematic wiring directly in the project.