AC Infinity Fan Adapter

This project is a small KiCad adapter board for controlling an AC Infinity Cloudline fan from a controller fan header that provides an open-drain PWM output.

The current design is aimed at controllers such as Antminer and Bitaxe boards. The adapter translates the controller-side PWM signal into the Cloudline UIS PWM input without exposing the controller PWM node to the fan's internal 10 V pull-up.

Project files

• acadapter.kicad_pro: KiCad project file
• acadapter.kicad_sch: schematic
• acadapter.kicad_pcb: PCB layout
• doc/acinfinity-usbc.md: Cloudline connector pinout and interface notes
• doc/render.png: PCB render

Design summary

The Cloudline fan uses a proprietary UIS connector on USB-C pins. Based on measurement so far:

• Cloudline PWM is pulled up internally to +10 V through about 10 kOhm
• direct connection to an unknown controller PWM output is not assumed safe
• the adapter uses the Cloudline +10 V rail to generate a local +5 V rail
• a two-transistor buffer recreates an open-drain PWM output for the fan side

The current design note and rationale are documented in doc/acinfinity-usbc.md.

Status

This is an in-progress hardware project. The PCB and interface notes are in the repository, but the design assumptions should still be validated against real hardware before treating the board as production-ready.

License

This project is licensed under the CERN Open Hardware Licence Version 2 - Strongly Reciprocal (CERN-OHL-S v2).

See the LICENSE file for the full license text.