Power Supplies: Speeding Time to Market for Medical Equipment

Today’s increasingly challenging system requirements and accompanying shortened design cycles put more pressure than ever on medical equipment designers. Both can be seen as a major contributor to projects being delivered to market late, especially if a problem identified in testing leads to an extra design spin. Indeed, it is estimated that the average new product development schedule overruns by up to 20 percent — which could be as much as six months for major new medical designs. Naturally, the consequences of being late to market are very wide ranging and can have a significant (negative) impact on a medical OEM’s business.

This article explores the effect that late product launches have on medical designs and looks at ways that intelligent insight from equipment power supplies can play a key role in getting a project to market on time.

The Medical Equipment Market and Power Supplies

The medical equipment market is large and diverse, encompassing everything from MRI machines and other whole-body scanners to small ambulatory devices that are worn by the patient, either temporarily or long term. According to research firm Fortune Business Insights, the global market for medical devices was worth US $432.23 billion in 2020. While this declined slightly during the pandemic, the market is expected to reach US $657.98 billion by 2028, representing a CAGR of 5.4 percent (see Figure 1).

This growth is being driven by increasing prevalence of some chronic conditions as well as a strategy for early diagnosis and treatment, which is leading to more patients undergoing diagnosis and, in some cases, surgical procedures — requiring more medical equipment.

Due to the breadth of equipment deployed, there is a corresponding diversity of power supplies used in medical applications, encompassing everything from small external devices through to large and complex power systems in scanners. One of the principal differentiators of power solutions in medical applications is the safety requirements.

All power supplies used in medical applications require enhanced safety compared to, say, an office application, to provide protection to the patient as well as the medical professional operating the equipment. The safety requirements become particularly stringent in applications such as ECG where the patient is directly connected to the equipment.

Additional challenges in medical applications can include the need for quiet (fanless) operation as well as requirements for sealing so as to protect the power supply against liquid ingress during cleaning or disinfecting procedures.

Getting to Market Quickly

Often, the reasons for wanting to deliver a new product to market quickly are commercial. The manufacturer would benefit from enhanced revenue and market share if they are the first with a new technology. While this remains true in the medical sphere, there is often a clinical need as well — the faster a product is delivered, the better the health outcomes, whether it’s treating people earlier or saving lives (see Figure 2).

When a product is delivered to market early, it can enjoy a longer time before it becomes obsolete and greater market share during the longer life cycle. It has been estimated that if a product is between 9 and 12 months late to market, then 50 percent of the anticipated revenues can be lost, turning a profitable project into a loss-maker.

Often the power solution is one of the last aspects of a design to be considered. One of the primary reasons for this is that, until the system design is relatively stable, the voltages and currents needed for the system are not fully known — potentially leading to a requirement to select another power solution — delaying the market release.

The greatest challenge in reducing time to market is ensuring that testing and qualification are passed first time, every time as every respin of the design introduces significant delays and costs. While this is a simple concept, it is often difficult to execute, particularly in complex equipment. As more features are added to even the simplest device, the testing requirements grow, requiring every corner of the specification to be tested, often (slightly) beyond its limits.

Intelligent Solutions Support Shorter Design Cycles

As systems and end-products have become more sophisticated, so have the power solutions that they incorporate. Perhaps one of the most significant advances in power supply intelligence has been the advent of the Power Management Bus — or PMBus™. Developed by several leading power supply manufacturers, including founding member Artesyn Technologies (now part of Advanced Energy), the PMBus is a standard means of communicating with a power device over a digital communication bus.

The PMBus offers greater robustness and more features than other approaches, including I2C (with which it retains some electrical compatibility). When deployed, PMBus can be used by a system processor to configure, control, and monitor the power solutions – mostly with respect to voltages, currents and temperatures.

When qualifying a new medical product, a variety of tests are performed over a period of days or weeks, depending on the complexity of the product concerned. This process can be labor-intensive with technicians recording key parameters during the testing phase. However, if a PMBus-capable power supply is used, then the inbuilt monitoring function can be used in place of the technician to record data. As the monitoring can be faster and be done with more consistent accuracy thanks to the removal of potential human error, this approach can give designers more granular data and better intelligence with which to analyze system performance.

For example, the data set can determine voltages and currents throughout the test, while the system is cycling through all its functions. This allows designers to check that the power supply is correctly specified for the task in hand, as well as confirming that current draws are as expected, and the system is operating as it was designed to do.

By producing valuable, accurate data first time, every time the PMBus monitoring can make a significant contribution to reduced time-to-market, not least as it releases the technician(s) to contribute elsewhere on the project, instead of sitting noting down results.

Furthermore, the usefulness of PMBus monitoring in terms of delivering optimized, reliable power supplies goes beyond the design and qualification testing stages. During extended production testing (including burn-in), for example, test jigs can be significantly simplified by using onboard PMBus monitoring instead of building dedicated test fixtures. And, finally, once the power supply is deployed in the field, then monitoring for unexpected changes in the operating parameters is highly valuable in detecting impending failures before they cause downtime — essentially, the power supply can be used as a window to the health of the wider system.

Modern, Intelligent Power Solutions

PMBus-capable modular solutions are ideal for medical applications. The Advanced Energy’s Excelsys CoolX^® 1000 power supplies, for example, brings all the configuration, control, and monitoring benefits discussed previously, while modularity allows the unit to be rapidly configured (and reconfigured) to meet specific application needs.

The power supply chassis has been designed to accept up to six power modules, allowing for a maximum of 12 isolated DC outputs ranging from 2.5 to 58 V. IEC 60601-1 (3rd edition) and IEC 60601-1-2 (4th edition, EMC) approval, 2× MOPP (means of patient protection) as well as dual fusing ensure compatibility with all relevant medical requirements (see Figure 3). Operation without the need for a fan is possible due to the high levels of efficiency (c93 percent). This enhances reliability, giving an MTBF of >2,900,000 hours and a five-year warranty, it also eliminates vibration and acoustic noise — both highly desirable in medical applications. A total of 12 different CoolMod modules are available, giving huge flexibility to configure sophisticated power schemes with minimal design effort.

The modular nature of the solution, and the flexibility of the individual modules, can be a significant benefit during the design process, if testing data indicates that design tweaks are needed. For example, if a voltage is toward the bottom end of its specification, perhaps due to a voltage drop in the cable, the voltage on the module can be increased slightly to compensate.

If the data shows that a module is close to its power rating, then a more capable module can be used (or two modules can be configured in parallel) to ensure design limits are not violated. Also, if a module is shown to be underutilized, then replacing this with a lower power module may enhance overall system efficiency.

The modular approach allows the design to be tweaked and honed with virtually no effort and certainly no impact upon the medical approvals which the CoolX^® carries in every configuration.

Summary

The market for medical devices is significant and is back in growth mode again. Unlike many markets where time to market is simply a commercial consideration, in the medical sphere it can be, literally, life or death.

Increasing complexity of solutions as well as the need for absolute reliability and safety means that qualifying a medical solution can often be complex and time-consuming, therefore expensive. However, using the intelligence built into subsystems (such as the PMBus capability on intelligent power solutions) can improve the granularity and accuracy of test data while releasing technician resources to work elsewhere on the project.

Coupling this with a modular power solution gives the ability to tweak the design in response to test data with minimal effort.

This article was written by Dermot Flynn, Director, Strategic Marketing, HV, LV – Advanced Energy, Denver, CO. He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.. For more information, visit here .