TMC4671+TMC6100-REF-TOSV is an open source reference design for ventilators / respirator systems. It is a BDLC servo driver for voltages from +12V to +36V and motor RMS phase currents up to 6A. It offers a wide range of connectivity with its SBC connector in Raspberry Pi style, the addon board header for a standard or custom pressure sensor addon board, and general purpose I/O. Communication is via standard TTL UART or RS485 (when using the standard addon board TOSV-SENSOR-REF).
More information: https://www.trinamic.com/solutions/medical/tosv/