Renesas Creates Open-Source Ventilator System Reference Design

April 15, 2020 by Paul Shepard

Renesas Electronics Corporation has introduced a new open-source ventilator system reference design that customers can use to swiftly design ready-to-assemble boards for medical ventilators. Many regions are experiencing a critical shortage of ventilators as COVID-19 infections continue to rise and hospital demand exceeds supply.

"Renesas' engineers have created a ventilator system reference design to address the challenges our global community faces as we fight the COVID-19 pandemic," said Chris Allexandre, Senior Vice President, IoT and Infrastructure Business Unit at Renesas. "Leveraging our broad product portfolio and system design expertise, we are enabling customers to accelerate their development of medical ventilator systems capable of operating in a home or hospital environment."

Renesas' engineers have followed several open-source ventilator designs, including the Medtronic PB560, to come up with an easy to assemble three board ventilator design. It controls the tidal volume and mixture of gas delivered to the patient while monitoring the patient's status. The ventilator is portable and can be used with or without gas tanks.

In addition, a humidifier can be connected to the ventilator's intake path to soothe the patient's breathing, making it more comfortable to be connected for long durations.

The reference design uses 20 Renesas ICs, consisting of microcontroller (MCU), power, and analog ICs that address many of the ventilator's signal chain electrical functions. The system design implements a sensor board, a motor control board, and features Bluetooth® connectivity that allows medical professionals to monitor several patients simultaneously via a tablet or other mobile device. Each board has a microcontroller (MCU) to control its specific task while monitoring the status of the connecting board. The ventilator solution also provides a system of checks and balances to enable regulatory approval and provide patient safety.

The system is using two MCUs for higher safety, so these devices can monitor and reset each other.

System Benefits

  • Secure system using two MCUs to monitor each other
  • System available for assist control mode and pressure control mode
  • Hardware is capable of providing low tidal volume, peak pressure, disconnect, and apnea alarms
  • Both gas volume and flow rate are monitored by the FS1023
  • The oxygen ratio is controlled by the valve, which is controlled by the MCU, and monitored by the flow sensor
  • The exhale pressure is controlled by MCU through the exhale valve
  • The oxygen sensor is used to test FiO2 (fraction of inspired oxygen)
  • The blower is controlled via pressure/flow sensor feedback
  • The LCD brightness is controlled by the light sensor monitoring ambient light
  • Features a battery balance monitor to extend battery lifetime