BATTERY LIFE CR Designing medical dev

RITICAL ices for EMC

features and charging capabilit y are as important to the overall product as the ergonomic design process is.

Design verificat ion engineers must ensure that electronic design meshes wit h mechanical design, compliance and approval testing.

Some of the more st ringent aspects of t he EMC regulations require very specific limit s on insulation, electrical isolation, impedance, creepage and clearance

tolerances. Meeting t hese limit s often requires optimising t he layout of t he printed circuit board (PCB) and

organising the best use of critical tracks. It’s also important to add additional filtering and snubbers to keep

noisy than chargers, smart bat contain microprocessors and dat communication lines, adding a furt source of RFI noise.

i h h b

Anthony Robinson, design verification engineer at Accutronics, looks at the implication medical devices, in light of changes m European IEC 60601-1-2 EMC regulations


he medical technology (MedTech) world has experienced a growing demand for more port able and wearable devices in the last few years. However, these devices require lighter and equally portable batteries and chargers t hat use switch mode power supplies (SMPS), a technology that is prone to higher electromagnetic interference (EMI), impract ical for devices int ended for use in life critical medical environments.

Keeping pace with batt ery technology, customers now demand increasingly light er, faster and portable chargers. However, while low loss power

conversion has improved t his t echnology, a by-product of the high frequency

switching process is that electromagnetic and radio frequency interference (EMI/ RFI) is increased.

LEGISLATORY CAP ON EMI As medical devices are used in professional and home healthcare

environments, it’s important t hat EMI levels are minimised to eliminate the risk of interference with, and voltage fluctuation of, life-critical devices such


as heart monitors, electrocardiogram (ECG) and anaesthesia machines, and

ventilators. T o control allowable limits of EMI, medical technology must meet t he regulations specified in European IEC 60601-1 t hird edition legislation, covering the general requirements for t he safety and performance of medical electrical equipment. Further to this, it must also fulfil t he standards laid out in IEC 60601-1-2 fourth edit ion legislation, a collateral criterion for electromagnetic disturbances, int roducing specific tests and requirements.

CONFORMING THE DESIGN TO LEGISLATORY STANDARDS Cust omers are usually conscious of creating a device wit h a very low

suscept ibility to EMI. However, one of the

biggest challenges that companies face

is battery integration as an aft erthought, in spite of the fact that smart battery

Accutronics / ELECTRONICS

“Design verification engineers must ensure that electronic design meshes with mechanical design, compliance and approval testing”

on engineer at s of modelling made to ations

The technical layout for a medical battery, specially tailored to EMC safety protocol


AN APPROPRIATE SOLUTION If a customer has alr

ringing and resonance at an absolute minimum. Although batteries are less i

smart batteries sors and data

s, adding a further


external product, leaving a very footprint to design a batt the battery cannot b without sacrificing e

leaves just enough space t PCB, with no space for any

ready designed the aving a very limited a battery and PCB, be made any smaller nergy density . This pace to fit a blank

In situations like these, companies must work with client

mechanical, electrical and ergonomic characteristics of the batt while minimising the

and susceptibility to electromagnet interference (EMI). As the indust demand and design qualit and wearable devices grows, the cat and mouse game bet chargers will continu

electromagnetic As the industry

qualit y of portable s grows, the cat

wireless inductive charging will continue to challenge design engineers t more novel methods of batt

selection. Placing it at the forefront of the design and development ensure that smart-fe

will remain unhampered by limitations, ultimately


To pre-empt these challenges, medical device OEMs must p

lopment process will eature progression ered by electrical

ely allowing OEMs to

improve functionality whilst complying with EMC safety standards.

t ween batteries and ue. Trends such as harging will continue engineers to produce s of battery design. e challenges, medical rioritise battery

for any components. hese, companies nts t o optimise the al and ergonomic e battery’s design, e transmission

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44