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Power supply design for medical equipment in a crisis

Market news |
By Nick Flaherty




Our entire industry is experiencing unprecedented levels of disruption, as shockwaves from the largest pandemic in almost a century continue to hit. TThe need to ship vital medical equipment and instrumentation is intensifying on a daily basis – and production sites, along with the supporting distribution channels, must respond accordingly.

This calls for a radical upheaval of what had previously seemed to be extremely effective business models. The rules of this particular game just got switched around.   

Over the last two decades, the global electronics ecosystem had been gradually altering the way in which it fundamentally worked. In order to prevent having to tie up large quantities of capital (and the financial risks that came with that), it had shifted further and further towards what was predominantly a build-to-order (BTO) culture. This has now become deeply ingrained within each stage of the supply chain, from the component vendors and their distribution partners, through to the equipment producers and the system integrators. Now, quite unexpectedly, everything we were once certain of is entirely different. The methodologies that have served the electronics business well for many years are no longer as applicable as they once were – and everyone involved must quickly adjust.  

In the past, it was perfectly acceptable (and in most cases recommended) for equipment manufacturers, whatever market they were involved in, to follow a just-in-time (JIT) production strategy. This meant elevated operational efficiencies could be maintained, avoided excessive inventory being amassed and safeguarded against abrupt slumps in demand. All that was needed was access to accurate projections about what volume requirements were expected to be.

As a result the quantities of components that were freely available were generally not that high. Through the levels of stock they carry, component distributors have had an important role to play in preventing shortages. They have been able to provide some buffering on occasions when unanticipated increases in demand were witnessed. However, these companies will only keep hold of large unit numbers for product lines where a sudden rise in shipment volumes is potentially foreseeable. They are less likely to do this for what are perceived as niche areas – such as medical equipment would normally be considered.

Production of certain items of medical equipment has markedly increased in recent weeks, but vendors’ limited reserves of key components have proved to be an issue, with lengthened lead times resulting. In such equipment designs, the constituent components have already been specified – meaning that it is necessary to either procure more of these components from a reputable source, or seek out a viable alternative. Substitute components, which are often referred to as ‘crosses’, will need to have adequate stock available and effectively offer a drop-in replacement. The latter point is going to be the greatest challenge here, as the component part must have equivalent physical dimensions, identical interfacing characteristics, plus comparable operational performance and breadth of functionality. 

Some power supply units (PSUs) may be suitable to act as crosses for units from other vendors, and CUI is working with medical equipment manufacturers to help them in this regard – finding them suitable alternatives from our portfolio. When a manufacturer is looking for a replacement, the datasheet of the alternative PSU should be thoroughly scrutinized before any purchasing activity is initiated. It can thus be ascertained that all essential attributes are adequately covered. Any potential discrepancies will need to be discussed, in detail, by the respective engineering teams of the medical equipment manufacturer and the chosen vendor. 

Power supply units (PSUs) intended for use in items of medical equipment will, of course, need to comply with strict quality standards. Extensive regulatory testing is required to assure safe and reliable long-term operation. A PSU design project that is about to be embarked upon, any modification to an existing PSU design, or the bringing on line of a new production facility will, under normal circumstances, all equate to several weeks’ worth of approval activity.

Given the current need to supply hospitals with greater numbers of ventilators, for example, new manufacturers from outside the medical sector are currently being commissioned. As a result, regulatory bodies on both sides of the Atlantic have taken steps to temporarily ease off on the stringency of their policies. For instance, a modification of an existing ventilator design from Penlon is being  manufactured by a new cooperation between Airbus and F1 team McLaren. The modifications were fast-tracked through UK regulatory approval and has been approved for production.

Things can be done from an engineering perspective too though. By taking a design approach that is based on modular building blocks, rather than a highly integrated system, the process to procure required components can be made less challenging. Although modules will still need to exhibit functional equivalence and could also need to have the same dimensions and interfacing as the original, this will not apply to the components that are incorporated into them.

Reliance on industry standard connectors, rather than employing proprietary arrangements, will increase the chances of finding a PSU module that will fit in with the design. Likewise, the specifying of common PSU voltage levels will also make the job of sourcing suitable units that much simpler.

Though admittedly there are certain compromises, in terms of system performance, size and overall cost, modular design practices offer clear benefits in scenarios like the one we find ourselves in today. Hence, they should see more widespread adoption. Much quicker access can be gained to the high volumes that acute demands are currently dictating, thereby allowing equipment production output to ramp up within a much shorter time frame.

The medical equipment industry has had to go through a very steep learning curve in recent weeks, as it looks to deal with a set of circumstances which are unlike anything that has happened before in living history. The knowledge being gained is proving invaluable though, with manufacturers and their suppliers quickly adapting to the situation. Major changes are being made to design and production strategies that will bring greater agility to the supply chain – and this, in turn, will help to save lives.

www.cui.com

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