On health and medical electronics

Kevin Parmenter, PSD Contributor



Kevin Parmenter, PSD Contributor

The world of medical electronics is changing in new and exciting ways – the wearable’s market opens up the ability of consumers being able to take some of the monitoring and analysis which you used to have to have a physician order tests for.

Individuals can use wireless connectivity to monitor their own health sensors via cell phone apps and Bluetooth, Wi-Fi –the cloud and such. 

Of course all of this needs to be powered via energy harvesting, batteries, super capacitors and chargers, including wireless charging.   This extends to the professional medical equipment, which is now benefiting from consumer electronics technologies, which now drive the standards.  Part of the downside of this consumer technology fast design cycle driving technologies is end-of-life issues. 

Many medical electronics products take so long to develop and get approvals on that the day the products are released companies are typically battling end of life and obsolesce issues.  Organizations, which can maintain products and not change things for years and years, will be preferred more than other suppliers who have consumer life cycles and impose them on the medical market.  Other issues are that wireless technologies in the medical environment can and have caused EMI- EMC problems. 

The global standard for medical electronics now includes mandatory 60601 4th edition EMC starting in 2017-2018 depending on country - region.  Most medical electronics companies have taken a position of its mandatory on all new designs.  This standard includes susceptibility as well as radiated emissions. 

We know patients and practitioners are bringing phones and such into the medical environment – this should not interrupt the equipment and the equipment should not interfere with the wireless telemetry used in the hospital.  Professional medical equipment is going from hospitals to being more portable for home healthcare including nursing homes and doctors offices and clinics – we see requirements for Class II (in this case meaning no ground connection) this is similar to the CF (cardiac floating) requirement for touch leakage current.

These requirements for line-connected equipment are even more stringent   than the already stringent B and BF rated medical equipment.   When possible, wireless charging enables lower-power diagnostic instruments to be charged, used, then stored with no holes for fluids intrusion since it is operating from a stored charge with no external conductive path.  

Equipment is also expected to survive shock and vibration when it gets transported on the ambulances – slammed in the back of the elevators and casters hitting the space in the floors on the carts –or in the helicopter to the medevac or ambulance and surviving inevitable user mishandling i.e. dropped.  Speaking of medical carts – these will need to be wirelessly charged too, and when either undocked or unplugged to move they will need inverters – UPS systems and super capacitor banks (or batteries) so they can be moved from one place to another in the medical environment and operate for 30 min or more being used until reconnected.

The IoT is also a factor here, as the equipment is expected to be connected to the web and securely communicate test results.  This also allows services where the service tech may not have to visit the facility to diagnose and repair issues in the equipment and service contracts will include monitoring the PMBus-enabled power supply to read power and temperature, voltage levels and such to predictively be able to contact someone if a something is blocking the air inlets for cooling fans, or if a motor is reporting high current limits or such. 

Since emerging economies want quality medical care in the BRIC countries of Brazil, Russia India and China plus others some of these countries have power grids which are less developed and thus the ability to survive 300 VAC surges for 5 seconds, high surge to meet K.21 enhanced transients on the power line – by law hospitals in many regions including North America are required to test their emergency generators once a week – this can cause power line transients and sags- surges.    

If this were not enough we have 5000-meter altitude requirements for the power electronics to work meet creapage and clearance requirements to be approved for entry and sale in high altitude countries or for use in aircraft.  These and other requirements tend to “thin the herd” and it will indeed take a long-term orientation and diligent efforts to meet the stringent requirements mandated by these applications.  The plethora of power electronic opportunities are plentiful from energy harvesting to three-phase power for X-ray, radiation equipment and MRI and everything in between the future is bright indeed.