App note from Maxim Integrated about the design of modern ventilator system. Link here
This application note provides an overview of ventilator systems with a focus on system design for precision measurement and reliable protection. It discusses the four key components of a pneumatic ventilation system: gas supply, gas flow mixture, inhalation and exhalation systems. Within each of the components are a variety of sensors including pressure, flow, humidity, and temperature sensors. These sensors provide feedback to accurately control solenoid valves to ensure the air volume, pressure, and air-oxygen mixtures are delivered to the patients at specified intervals. Included in the system design are several fail-safe features and alarms to ensure reliable operation in any condition.