Category: Analysis

Consumer Healthcare
By Sukie Whitehall
August 18th 2022
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Sukie Whitehall

Consultant Mechanical Engineeru202f

Demystifying FemTech innovation: your questions answered

In an exciting first half of 2022, our FemTech team attended and presented at conferences, including the Reproductive Health Innovation Summit in Boston and the Women’s Health Innovation Summit in Basel. We’ve enjoyed fascinating conversations at events like these, covering everything from whether ‘FemTech’ is a useful term to how FemTech can manage the gender data gap. In this article, we share our responses to some of those questions which stood out to us.

Is ‘FemTech’ the right term to use to discuss this space?

Yes – and no. The term ‘FemTech’ has been a valuable tool since Ida Tin coined it in 2016, but it can narrow the field of focus. FemTech gives investors a framework and ‘safe’ vocabulary to discuss women’s health issues – some people find “I’m investing in FemTech” easier to say than “I’m investing in a period tracker.” A Google search on the term shows that it has evolved into a rallying point for like-minded people in the industry to find each other and drive innovation. At CDP, we view FemTech as a design philosophy underpinned by inclusivity, experience-led design, and the smart integration of tech (or intentional absence of tech), which we overlay on wide-ranging areas of innovation.

How important is it that FemTech designs for the planet?

We can look at how FemTech has grown due to an increasing consumer focus on sustainability. Menstrual cups, for example, have been around for a long time but only recently become a mainstream product. In 2018, the global menstrual cups market amounted to an estimated US$1.2 billion – it’s expected to reach US$1.89 billion by 2026. This increase reflects a massive shift in consumer attitude towards prioritizing sustainability over the last few years. But it also shows the success of products that meet user needs. Menstrual cups generally need to be changed less frequently than conventional tampons, so they meet user needs and offer a sustainable alternative. [1] At CDP, our user-centered design approach means we design for people, first understanding what they are trying to achieve, before translating contextual insight into solutions.

How is FemTech managing the gender data gap?

Historically, medical studies have often assumed the male body as the default, ignoring that women have different physiologies and responses to disease. This has resulted in a lack of data focusing on women’s needs, which puts FemTech innovators at a disadvantage. On the other hand, it also presents an opportunity for the industry to create valuable proprietary data which can be shared to further the understanding of women’s health. Take the vastly under-researched area of female sexual pleasure – the first comprehensive anatomical study of the clitoris was only published in 1998. [2] For Goodness Sake is the parent company of OMGYes, an education app focused on female sexual pleasure. In partnership with Indiana University and Kinsey Institute researchers, it researches people’s most intimate and vulnerable experiences. The results are published in peer-reviewed journals and (to quote their literature) “turned into honest and friendly online products” – the best of both worlds.

What are some best practices when it comes to developing FemTech products?

The most important thing is not to treat each stage in the innovation journey as a discrete process but to communicate between disciplines and, critically, with consumers and patients – put them at the heart of the innovation process, and validating the new product or service experience. This will ensure that, for example, manufacturing decisions won’t negatively impact user requirements. Our advice is to apply our FemTech philosophy of inclusivity, user-centered design, and the smart integration of tech to a robust end-to-end innovation process, such as CDP’s Potential Realized. This comprises six steps: opportunity definition, concept creation, concept realization, product realization, manufacturing realization, and life-cycle management.

How should emerging FemTech companies approach regulation?

Many FemTech products sit with one foot in healthcare and the other in consumer. Knowing which category your product falls into is key to avoiding unexpected regulation (our white paper on FemTech regulation has more information on this). Consider regulation early, as compliance is complex and expensive to retro-engineer. Negative PR following a regulatory oversight could be catastrophic for a new company or brand, which might otherwise have been successful. And even if you find your product is exempt from regulation, it’s good practice to take a risk-based approach to design to ensure your product remains safe and enjoyable for its end users.

REFERENCES

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For more on how to design inclusive, experience-led FemTech products that meet the real needs of women, contact Cambridge Design Partnership.

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How to boil your egg perfectly every time
April 14th 2022
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How to boil your egg perfectly every time – according to simulation

Search ‘how to boil an egg’ on Google, and you get over three billion results, some telling you to put the egg in cold water after boiling to preserve the runny yolk. Intrigued, we decided to investigate the science behind this advice.

Rather than heading straight to our lab for experimentation, we used computer simulation to calculate and model the movement of heat and temperature through the egg and surrounding fluid. Simulation lets us predict data at times that would be impractical or expensive in actual experiments.

Modeling the heat flow in a boiling egg could be a surprisingly tricky problem. An egg consists of a solid shell holding the white and yolk, initially in a liquid state but solidifying as the cooking continues. Being natural products, the exact properties and sizes of eggs vary.

To simplify the problem, we found technical publications that describe the average dimensions and thermal properties of the shell, white, and yolk for a typical egg. We decided to define these properties at a temperature of 60°C, which is around the point the yolk starts to solidify. Using computer-aided-design software, we created the geometry of the egg, and defined a body of fluid to surround it. This fluid body represents the boiling water in a saucepan during the first cooking stage. Afterward, the fluid body can be used to mimic cool-down in air or a bowl of 10°C cold water. We decided that the eggs would start the process from room temperature in all cases.

We ran the simulation using powerful software, Ansys Fluent. The software was initially developed for understanding problems such as the flow of air over planes or heat in a chemical plant, but it can be applied to domestic problems such as the humble boiled egg. To allow the simulation to run quickly on an ordinary computer, we took advantage of the fact an egg shape is a body-of-revolution and looks the same however it’s rotated around its axis. This lets us model it as an axisymmetric body that the computer considers two-dimensional. This reduces the number of calculations and gives us the answer quicker and more cheaply than simulating the real-life, three-dimensional shape.

As an example of the simulation results, Figure 1 shows the temperature distribution on a slice along the egg’s axis after cooking in boiling water for six minutes. The material towards the outside has heated up close to the temperature of the water. However, the central region corresponding to the yolk is still around 50°C, corresponding to a runny egg.

Figure 1: Temperature distribution on a slice across the egg after six minutes of immersion in boiling water.

Figure 2 shows a side-by-side comparison of subsequently cooling the egg in air or 10°C water for five minutes (five minutes being our estimate of the time it takes to finish eating our first dippy egg and move on to the second). When cooled in air, the central region of the egg continues to increase to 70°C, removing the prospect of a runny egg, even though the outer region and shell have decreased in temperature. In contrast, after cooling in water, the central region stays unchanged at 50°C while the shell has decreased close to 10°C. Leaving your perfect dippy egg in air risks ruining the runny yolk – but cooling it in water may save it.

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Figure 2: Temperature distribution on a slice through the egg following cooking
and five minutes of cooling in (a) air and (b) water.

As well as modeling the overall temperature in the egg, we extracted the data for two specific points – at the center and the edge of the egg – and plotted them on a graph (Figure 3) to see how they differed. The data showed that the yolk’s temperature lags that at the shell. This is because the thermal diffusivity of the white and yolk are relatively low. Thermal diffusivity is a measure of how quickly heat can move through a material. So, it takes a while for the yolk to heat up, but once it does, it keeps cooking, absorbing heat from the rest of the egg material. It’s slow to respond to changes in the surrounding water (or air). The temperature just inside the shell responds much more quickly to changes, though, since the path the heat needs to travel from the surrounding fluid is considerably shorter, and the thermal diffusivity of the shell markedly higher.

How to boil your egg perfectly every time|||||||
Figure 3: Temperature profiles with time at the center point of the yolk (circles) and adjacent to the shell (crosses)

With the aid of some considered simplifications, we think this simulation analysis has proven the cookery expert right: cooling eggs down in cold water really does preserve the runny yolk. However, whenever you analyze a problem for the first time, it’s important to compare results against an experimental benchmark, so you can confirm the realism of the assumptions and simplifications in a computer simulation. We took three eggs and boiled each for six minutes in a lab beaker. One was opened straight away, and the other two after cooling in cold water or in air for five minutes. As predicted by our computer simulation, the yolks ranged from runny to fully cooked. And the best thing about this experiment? Everyone got an egg cooked precisely to their liking at the end.

 

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By Dan Haworth
April 5th 2022
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Dan Haworth

Head of Diagnostics

Reducing the carbon footprint and plastic waste of LFTs: Evidence-based opportunities

Billions of lateral flow tests have been used worldwide during the COVID-19 pandemic – over two billion have been provided in the UK alone. Debate has raged on social media about why the tests need to use so much single-use plastic and how they could be made more ‘sustainable’. The test strip caseworks is a particular source of dismay – why so much plastic to house such a tiny test strip?

With the UK government ending the free distribution of lateral flow tests for the general public – citing a transition from emergency response to longer-term management of the pandemic – now is the ideal time to look more closely at the sustainability of these lateral flow tests, and to seek the data to demystify some of the emotional assumptions being made.

Familiarity with lateral flow testing has certainly increased, as has confidence in their clinical performance. It’s expected that lateral flow devices will be more present in our daily lives post-pandemic – not just for COVID-19 and pregnancy testing but to diagnose diseases such as seasonal influenza and sexually transmitted infections – all from the comfort of the home.

We’ve carried out a high-level assessment to quantify the approximate environmental impact of lateral flow tests and identify evidence-based suggestions for improving their environmental sustainability.

Why do COVID-19 lateral flow tests contain lots of single-use plastic in the first place?

The emergence of COVID-19 was a global emergency, and vast quantities of lateral flow tests were needed urgently. Once developers could produce the right immunoassay chemistry to detect the virus (SARS-CoV-2), it required implementation in a low-cost, low-risk device, that has a mature supply chain – with proven, readily available materials that wouldn’t compromise analytical or clinical performance.

This meant using existing plastic casework designs to retain and protect the nitrocellulose test strip. Plastic is robust, low cost, lightweight, easy to transport, and easily printed for QR codes and LOT numbers. Critically, it’s a consistent material proven for the highest volume manufacturing and won’t interfere with the immunoassay chemistry.

From a performance, cost, and manufacturing perspective, redesigning the product with new materials would have been high risk. Material changes may also have needed significant R&D costs, new capital equipment as well as additional cost and effort needed to demonstrate equivalence and achieve regulatory approval – risking the ability to provide sufficient numbers of high-quality tests, at speed during the pandemic.

Our results: The sustainability of lateral flow tests

But how serious an environmental impact do these tests have? To find out, we broke down a test into its constituent components and weighed them to calculate the approximate environmental impact, using standard emissions factors to calculate the carbon footprint of a single test.

web_body_lateral-flow-test-kit-1

We focused on carbon footprint (the carbon dioxide and other greenhouse gases emitted during manufacture, transport, and disposal of the tests) and plastic waste (waste that would persist indefinitely if released into the environment) – the two issues that have attracted the most attention around lateral flow tests. A more comprehensive study should consider a broader range of environmental impacts, for example, the use of scarce resources and emission of other pollutants to avoid unintended consequences of any product changes.

Our results reveal:

  • The components needed to conduct the test account for around half of the carbon footprint and around two-thirds of the plastic waste. Packaging makes up most of the rest – as is often the case, a surprisingly high proportion of the total environmental impact
  • The test strip caseworks, which attracts the most comment online, is responsible for around 30% of the carbon footprint and 40% of the plastic waste. While it’s the most significant single contributor to the environmental impacts we evaluated, the large number of other small parts is also significant. Focusing on the caseworks therefore might not be the best strategy for improving the sustainability of the tests overall.
web_body_lateral-flow-test-analysis-1a-2
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Lateral flow tests a minor piece of UK healthcare’s environmental impact

To put these numbers into context, we can compare the environmental impact of the two billion COVID-19 lateral flow tests distributed in the UK with the UK healthcare system’s overall environmental impact. We estimate the UK’s lateral flow tests have a carbon footprint equivalent to around 0.5% of the total NHS carbon footprint. This isn’t a trivial amount, but it’s also not the largest single contributor to the impact of the UK health system.

It’s also worth considering the positive environmental impact of a user-administered test on the health system. Conducting a test at home can eliminate the need for an individual to visit a test site, GP’s surgery, or hospital (assuming the clinical performance of the lateral flow test is adequate). Based on estimates from the Sustainable Healthcare Coalition, one lateral flow test has around 5% of the carbon footprint of a single GP appointment and produces a similarly low percentage of non-degradable (plastic) waste.

And that’s before we consider travel. We estimate one lateral flow test has the same carbon footprint as driving 350 metres in an average UK car. So, if you’re driving yourself to a test site or GP surgery some distance away, at-home lateral flow tests compare even more favorably.

If a lateral flow test prevents an individual from transmitting COVID-19 to a vulnerable person, there’s a public health benefit – as well as an environmental benefit – to keeping people out of the hospital. We can all see the discarded waste from home tests, but the less visible impact from energy- and material-intensive medical interventions is often significantly higher.

These approximate figures demonstrate why building an evidence base is vital during product development targeting sustainability objectives – because the results can be unexpected and non-intuitive.

Quick ways to optimize today’s lateral flow tests

Just because waste from lateral flow tests might not be the most urgent sustainability issue for UK healthcare, that doesn’t mean we can’t and shouldn’t do something about it.

We used the ‘avoid/shift/improve’ model to find potential quick wins for lateral flow tests. These reduce the carbon footprint of each test by nearly a third and the plastic waste by almost a quarter – without impacting the fundamentals of how the test works.

They include:

  • Eliminate waste bags. There’s a case for quickly isolating contaminated waste (even given COVID-19 also spreads from infected individuals through the air), but the bags account for around 5% of the carbon footprint of the test. It’s not clear how widely used they are in a domestic setting – there may be a risk-based justification for not including them in the test kit.
  • Package all the test strips in a single foil pouch. Using a single re-sealable pouch to protect the tests from ambient humidity (rather than individually packing each test in a pouch with desiccant) is common in packs of lateral flow tests designed for use by healthcare professionals. However, once opened, the stability lifetime of the remaining tests is affected.
  • Reduce the size of paper instructions. These are important for the effectiveness of the tests and are a regulatory requirement, but account for 5% of the carbon footprint of a test – could they be reduced in size?
  • Eliminate the cardboard sleeve. This packaging isn’t essential to the safe and effective functioning of the test, and it seems likely that the functions it does provide could be achieved with less material.
  • Prefill the extraction tubes with buffer solution. This is already done in some test kits, although manufacturers need to be conscious of moisture loss and the effect on shelf life. However, the separate plastic vial used in the test kit we studied accounts for around 5% of the carbon footprint and plastic waste.
  • Increase the size of the pack from seven to ten tests. This would mean less package waste per individual test. Including ten tests in one pack instead of seven reduces the carbon footprint by around 5% (depending on how many other optimizations are done at the same time). Perhaps a pack of seven tests was originally designed to cover a week of daily testing – but is that how tests are being used in practice?
web_body_lateral-flow-test-analysis-2

Redesign of the test strip caseworks

Looking to the longer-term gets us into product redesign – creating a new generation of the product with sustainability in mind. Doing this can take significant investment since, for medical devices, it’s likely to require new regulatory approval, which is a lengthy and costly process.

A popular idea circulating for lateral flow tests is to minimize the plastic test strip caseworks (without compromising the essential functions of providing a stable platform, and protecting the nitrocellulose test strip). It might be possible to halve the caseworks mass and reduce the overall carbon footprint and plastic waste by 15-20%. This would require significant investment in R&D, production tooling, and regulatory approval hoops to jump through – but could be worthwhile if future demand for tests stays high.

Longer-term options

If we consider that the world may require billions more lateral flow tests over the coming decade, a more comprehensive redesign becomes commercially viable. This could involve stripping the design back to the fundamental requirements for a lateral flow test – flowing a sample through the test strip in a way that is controlled and free from contamination. Current designs take advantage of established components to collect, buffer, and dose the sample – but, at this production volume, it may be worthwhile designing a system from the ground up that is optimized for cost, usability, performance, and sustainability.

Sustainability as a brand differentiator

It’s clear there’s scope to optimize lateral flow tests to reduce their environmental impact – and a systematic analysis reveals options beyond those that might jump out to someone when they use the tests. But it’s essential to put the impact of lateral flow tests in the context of the wider healthcare system, to focus resources where they can have the most environmental impact – and to recognize that, sometimes, the plastic waste people can see helps to avoid more serious, but less visible consequences.

On the other hand, while visible plastic waste from lateral flow tests may not be the most pressing environmental issue facing the healthcare industry, it highlights the growing influence consumer opinion is likely to have as diagnosis and treatment shift from hospitals to homes. And as lateral flow tests become (in the UK, at least) a product people buy with their own money, choosing from a range of options, there may be a competitive advantage for businesses that take note and optimize their products for sustainability.

References
  • Prime Minister sets out plan for living with COVID [Internet]. GOV.UK. 2022 [cited 1 April 2022]. Available from: https://www.gov.uk/government/news/prime-minister-sets-out-plan-for-living-with-covid
  • The Sustainable Healthcare Coalition. Care Pathways Calculator. [Internet]. Sustainable Healthcare Coalition. 2022 [cited 1 April 2022]. Available from: https://shcoalition.org/

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For more information on reducing the environmental impact of lateral flow tests without compromising performance, contact Cambridge Design Partnership.

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Mastering fluid flow to enhance user experience|
March 22nd 2022
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Mastering fluid flow to enhance user experience

Ice cream and blood are two things you probably don’t want to think about simultaneously. But both are full of organic proteins and fats and behave differently from a fluid like water when they’re pumped through tubes. Innovators sometimes think about these similarities when creating, for example, a novel ice cream dispenser or device that filters out platelets from donor blood .

How a substance flows is a vitally important consideration for many products, from foods to skincare to medical devices to household paints. Development teams need to keep in mind a wide range of flow behaviors (for example, flow through nozzles, non-Newtonian flow, and foaming) to hit the sweet spot: a positive user experience that makes a product stand out in a crowded market. This means thinking about the science of how liquids and gases behave (fluid dynamics), as well as how the product responds to user interaction.

Look at how the squeezable plastic ketchup bottle differs from the glass bottles that were standard before 1983. The new design completely changed the user experience – no more digging down into the bottle with a knife to get the ketchup flowing again. Things became even easier for ketchup lovers with the debut of the upside-down squeezable bottle – no more awkwardly storing ‘regular’ bottles upside down in the fridge.

Or think about how the experience of washing your hands changed after the arrival of the liquid soap dispenser. Instead of having to share the same bar of soap with others, people can now wash “without the soapy mess”, as Robert R Taylor, who introduced SoftSoap liquid soap, put it, and can take only as much soap as they need.

While the flow of some liquids is analogous to water, whose behavior is well understood, other substances behave in much more complicated ways, requiring in-depth analysis work to understand when designing new products. For example, the air bubbles in ice cream make it behave as a liquid foam. Ice cream’s flow will change depending on how you’re dispensing it: Push it at high pressure through a narrow channel or nozzle, and the air bubbles will be compressed, allowing more ice cream to flow through the nozzle at once. When the ice cream is returned to normal pressure, the air bubbles re-expand, and the ice cream returns to its original size. Because of this complex and variable behavior, designing a product to dispense ice cream relies on hands-on experiments… which can mean going through gallons of ice cream before you can create a design that works as intended. Only by conducting these experiments to understand ice cream’s behavior can you build the mathematical model required to effectively develop a high-performance machine.

While it’s a shame to use gallons of ice cream in the quest for a better product, it’s not an environmental disaster. But shipping water-based products around the world does contribute to fossil fuel consumption and climate change. Removing water from laundry detergent helps cut shipping emissions by reducing bulk and making shipping more efficient. But it also dramatically changes how detergent flows and gets used by consumers. For example, measuring out 10 ml more detergent than recommended likely wouldn’t have an impact if you’re using a product that’s mostly water. But being off by 10 ml when detergent is concentrated could make a big difference for your laundry. So, it’s vital to ensure that dispensing is accurate, which requires an understanding of flow.

There are so many flow behaviors that can affect a product’s design. For example, should a container for insecticide include a mechanism to avoid skin contact and spillage? How could a medical device for freezing tumors be redesigned to eliminate vapor locks without the use of heavy and bulky high-pressure gas cylinders? Is there a way to dispense foaming hand soap in a decorative pattern for a premium experience?

Getting the design right for a flowing substance can differentiate between a product that fails and one that creates an experience that shifts category norms and delivers breakthrough consumer delight.

References

FemTech : #2 Experience-led design
By Cambridge Design Partnership
March 10th 2022
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The three pillars of FemTech success: #2 Experience-led design

In the first of a series of articles covering the three pillars of our FemTech philosophy, we discussed inclusivity. Here, we move on to experience-led design, before ending with the smart use of technology.

Product innovation is shifting focus – from making things to designing seamless experiences. An experience-led design process leads to simple, intuitive, and enjoyable solutions, increasing customer satisfaction and retention.

How a user feels when using a product or service is becoming as important (if not more so) than the solution itself. More than ever, themes such as brand ethical position, purpose, and sustainability credentials are influencing where consumers place their cash and their loyalties. To address this, FemTech innovators must do three things:

  • Understand external influences
  • Focus on the end-to-end user experience
  • Leverage multi-disciplinary perspectives

Understand external influences

Understanding what drives change in the consumer and healthcare space is vital. The challenge for FemTech innovators is to understand how these factors will affect user expectations and behavior.

Take environmental factors: ‘flushability’ has long been a selling point for hygiene products, such as wipes and sanitaryware. However, some manufacturers have drawn historical criticism for stretching the technical definition of flushable to what may be sent on its way with the press of a lever. ‘Solubility’ is a more meaningful definition in the context of the environment and related consumer aspirations. These criteria are determined by industry standards such as Water Industry Specification (WIS) 4-02-06, ‘Fine to Flush’, and other standards with similar objectives across different international legislative jurisdictions.

Sanitary disposal bag firm Fab Little Bags is banking on consumer sentiment changing amid increasing awareness of water pollution. By providing a way to dispose of a tampon in a way that aligns with changing environmental beliefs – binning is better than flushing – it removes eco-guilt and improves the end-user experience.

Regulation is another factor that could affect user experience. If users know that a product, such as a fertility monitor, has been medically approved, they may feel more confident when entrusting it with a potentially life-changing task.

Focus on the end-to-end user experience

User experience isn’t limited to using a product or service but encompasses the whole consumer journey, including product research, purchase, delivery, unboxing, and after-life.

Consumers have ‘Moments of Truth’ during this journey – key points when they form an impression of a brand – and emotional and social drivers can have equal, if not overriding influence, over functional ones. The Zero Moment of Truth occurs during pre-purchase research. The intimate wellbeing e-commerce platform, Bloomi, which screens every product against a checklist of banned ingredients to ensure they meet its clean standards, recognizes the importance of this stage. The attention to the customer experience is continued with the promise of delivery in discreet packaging. Bloomi has designed a customer experience free of anxiety about harmful ingredients and privacy by considering elements of the user journey beyond use.

Leverage multi-disciplinary perspectives

User experience isn’t the remit of front-end innovation alone. Harnessing a multi-disciplinary team allows for a wealth of experience, perceptions, and viewpoints to be incorporated into the end-to-end design process. For example, our designers and engineers accompanied our research team to hear first-hand the frustrations women have when undertaking a breast cancer biopsy. This ensured that we could design an accurate medical tool and an empathetic user experience.

Certain environments, such as innovation sprint programs and start-up incubators, foster multi-disciplinary design. FemTech Labs, the first FemTech accelerator in Europe, is one example. It brings together experts, investors, and business coaches to kickstart FemTech businesses. The FemTech Lab accelerator program is short and intense, supplying opportunities for participants to grow quickly and sustainably by drawing on the expertise of its comprehensive interdisciplinary network.

As we’ve seen from the above examples, many FemTech companies are already prioritizing experience-led design as part of their development process. One of the mentioned case studies, Fab Little Bags, doesn’t ostensibly have any tech in it, which brings us to our upcoming article: the smart use of technology.

References

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For more on how to design inclusive, experience-led FemTech products that meet the real needs of women, contact Cambridge Design Partnership.

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By Cambridge Design Partnership
January 28th 2022
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The three pillars of FemTech success: #1 Inclusivity

Welcome to the first in a series of articles outlining the three pillars of our FemTech philosophy: inclusion, experience-led design, and the smart integration of technology. Here, we start with inclusion, a crucial topic for success in innovation.

While there are initiatives to ensure gender diversity in the boardroom, there’s rarely the same in product development. This need for equilibrium has historically often been overlooked in market research and product testing, resulting in design that misses a proportion of end-users. For example, it wasn’t until 2011 that female crash test dummies were introduced in the US.

There are three steps to achieving inclusivity in end-to-end innovation:

  • Understand the problem
  • Understand the context
  • Understand the ecosystem

Understand the problem

We use an Insights for Innovation approach underpinned by the ‘jobs to be done’ perspective. This focuses on understanding a task or ‘job’ independently of any existing solutions used to achieve it. This means we start with the problem rather than the solution. For example, our starting question is: ‘What needs might a couple have when trying for a baby?’ (the jobs), rather than ‘How can we design a biometrics tracker to gauge fertility?’ (a solution).

This solution-agnostic approach involves defining a ‘job’ in terms of the user’s functional, emotional, and social needs, for example:

  • The functional need to ‘know when I’m ovulating’
  • The emotional need to ‘feel like conception is a natural process’

An excellent example of a solution that has fulfilled these needs is Inne. This fertility monitoring system uses saliva to detect ovulation. Saliva analysis can help women increase the chance of falling pregnant (functional need) by identifying the fertile window each month. It offers clear feedback to reduce anxiety around the results (emotional need) and comes in a discreet format, allowing women to keep their fertility journey private, if they wish to.

Understand the context

FemTech teams must take research beyond quantitative surveys to truly have a clear idea of a woman’s needs. This requires in-depth qualitative interviews to understand women as part of a contextual system. This recognizes that women don’t buy a product because of who they are; no two women are the same; the same person can have different needs in different contexts.

We believe the team behind the breastmilk expresser Elvie Pump took this approach by considering the context of when it would be used, for example, while running after a child or in the workplace. This revealed needs far beyond extracting milk.

Historically, breast pumps have been cumbersome and noisy, with long tubes that significantly restrict movement. On the other hand, Elvie Pump’s design is hands-free, silent, cordless, and easy to clean. By addressing context, the design became a market leader in the US and UK.

Understand the ecosystem

Understanding the ‘job to be done’ as part of an ecosystem helps multi-disciplinary teams consider the experience of other key stakeholders.

Take the example of contraception; a heterosexual couple might have the same emotional need to ‘feel like contraception is natural’. However, to one, it could mean hormone-free cream; to the other, it might mean no physical intervention at all (for example, relying on a fertility monitor). Addressing the need from different perspectives ensures the solution is meaningful, intuitive, and enjoyable for everyone it impacts.

The Maven Clinic is a telehealth platform that offers fertility, pregnancy, postpartum, and family care services. It caters to what would largely be considered female needs. However, 30% of its members are men. Founder Kate Ryder is careful not to exclude them when she talks about the platform. Rather than referring to Maven Clinic as FemTech, she defines her mission in terms of “people” to ensure that all members feel included.

As these examples show, inclusivity is an essential ingredient of FemTech success. The following articles in our series will cover why experience-led design and the smart integration of technology are equally important.

References
  • Criado Perez C. The deadly truth about a world built for men – from stab vests to car crashes [Internet]. The Guardian. 2019 [cited 10 January 2022]. Available from: https://www.theguardian.com/lifeandstyle/2019/feb/23/truth-world-built-for-men-car-crashes
  • Science [Internet]. Inne.io. 2022 [cited 10 January 2022]. Available from: https://www.inne.io/en/science
  • Elvie Pump: from idea to execution [Internet]. Elvie. 2019 [cited 10 January 2022]. Available from: https://www.elvie.com/en-gb/blog/elvie-pump-from-idea-to-execution
  • Srivastava A. British femtech Elvie lands £58M funding for its smart breast pumps and more – UKTN | UK Tech News | [Internet]. UKTN | UK Tech News |. 2021 [cited 10 January 2022]. Available from: https://www.uktech.news/news/british-femtech-elvie-funding-20210727
  • Maven – The next generation of care for women and families [Internet]. Mavenclinic.com. 2022 [cited 10 January 2022]. Available from: https://www.mavenclinic.com/
  • Pallarito K. ‘Femtech’ Is Busting Taboos Around Women’s Health and Wellness—But What Is It Exactly? [Internet]. Health.com. 2020 [cited 10 January 2022]. Available from: https://www.health.com/mind-body/femtech-womens-health

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For more on how to design inclusive, experience-led FemTech products that meet the real needs of women, contact Cambridge Design Partnership.

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Pilot manufacture for drug delivery devices||
By Jon Powell
January 18th 2022
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Jon Powell

Head of Manufacturing

Prepare the way: Pilot manufacture for drug delivery devices

Bringing a drug delivery device to a clinical trial is a complex endeavor. You need to keep a handle on multiple moving parts, for example, the active pharmaceutical ingredient (API) development, the regulatory pathway, establishing the supply chain, and labeling. Developing a novel drug delivery device takes things to another level.

Many manufacturers shy away from the challenge, relying instead on proven technologies, so patients and clinicians don’t benefit from the most advanced user-centered design, and pharma companies can’t leverage the competitive advantage new technology delivers.

Here, I share some of the obstacles encountered conducting pilot builds in-house to help our clients bring devices to market – and give four pointers for ideal pilot manufacturing for clinical trials.

Develop your manufacturing process and architecture in tandem

3D CAD makes it all too easy to lose touch with reality and forget that the model on the screen is only an idealized representation. Zoom in 4,000%, and everything lines up beautifully. There’s no gravity, and parts have infinite stiffness, no tolerance, and perfect alignment. But, when you get natural variation in the manufacturing process, results can be disastrous. Components may not even fit together.

Once a design is frozen, making changes is expensive. After it’s passed to a high-volume manufacturer, costs become exponentially higher. Understanding manufacturing processes – and how changes can impact a project’s timeline – is critical for successful delivery. You need to prepare for the supply-chain ‘whiplash effect’: a tiny change at the top of the chain can mean seismic shifts at the end of it. That knock-on is the reason your product development strategy should incorporate pilot manufacture. Pilot manufacture keeps this effect in check by minimizing the volumes involved.

It’s vital to consider the whole supply chain, not just the component manufacturer, but the process equipment partners, filling, packaging, sterilization, and logistics. Each step has requirements to be understood and communicated to relevant parties. By developing manufacturing and assembly processes in tandem with device design, we can be flexible to insights arriving from either direction.

Pick the right partners for success

One of my first jobs was for a major automotive company. In their heyday, they ran the foundries that made the ball bearings for their vehicles. Today, they wouldn’t dream of it. No company does everything anymore. Few organizations would claim to be experts in all areas of drug delivery. Even those that manufacture and fill their own devices rely on external partners to produce the plastic resin and packaging materials and often outsource activities such as sterilization.

Partnering with experts to contribute specific knowledge is a time-efficient way to overcome obstacles in the development pathway. It also unlocks access to cutting-edge equipment and facilities that are expensive to maintain. While developing a breath-actuated inhaler, we engaged an external test house to conduct bio-compatibility evaluations on the device. We may have the skills in-house to perform this testing but maintaining accreditation for an activity that isn’t core to our business doesn’t make financial sense.

Know the limits

When developing a device, it’s essential to explore sources of potential variation. The same goes for the manufacturing process. You can use various tools to do this, but we frequently return to the humble ‘process failure modes and effects analysis’ (pFMEA). The pFMEA is a structured way to consider all the process steps – and how they could go awry. Developing a robust pFMEA ensures the team focuses on the highest risk areas and starts thinking about implementing mitigations.

A key checkbox for each manufacturing process step is if the results can be verified or validated. The US Food & Drug Administration Code of Federal Regulations Title 21 defines verification as “confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.” Many processes can be verified using in-process measurement systems. But several can’t, for example, the joining of two plastic parts by ultrasonic welding. You can’t determine the strength of this weld without destructive testing. The ultrasonic welding process needs to go through process validation to determine the limits within which the process should be operated.

When communicating with stakeholders, it’s crucial to know the volume limits and have a realistic plan for producing parts representative of the final production process. For example, how many parts can the mold tools make? There’s a trade-off between tool production speed, tool cost, and tool life. Low-cost soft aluminum tools might be ready in two weeks but only suitable for 2,000 shots, whereas a more expensive hardened steel version might take 16 weeks (without validation) but last for over 100,000 shots.

Validating injection mold tools can be a lengthy process. Exploring the process window needs planning and performing multiple molding and measurement runs and subsequent analysis. Companies only want to bear this cost once, so experienced development teams need to hold firm when encountering adverse test results. I know of an auto-injector that showed promise early on, albeit with an infrequent failure observed in testing during development, that was allowed to pass into design freeze. More thorough testing during design verification revealed results that triggered the regulatory application to be rejected. Cue months of tooling validation needing to be reassessed.

Combination products require the delivery devices to be filled or co-packaged with primary containers of the API. Clinical trials complicate this because they need devices filled with the API or safe and sterile placebo. The filling process can be complex, especially when the API is highly viscous or uses technologies such as microspheres to sustain the release of active components over time. You need to factor in time to explore the filling and develop the process settings. Thought needs to be given to the amount of API and placebo available and the lead times for new batches as this can limit the amount of filled and finished devices.

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Not documented? You’re not done.

Understanding the controls needed to manage risk is essential for a manufacturer delivering high-quality, safe, and reliable products. ISO 14971 sets out a best practice framework for managing risk in the context of medical devices. We advise creating a quality control plan that summarizes the production risk mitigation controls identified through risk assessment in a clear, concise format. This control plan also blueprints the actions needed if a specific limit or check is breached.

Anyone who has experienced an audit by a notified body or regulatory agency will recognize their love of records. The mature management systems used by large manufacturers often aren’t available for the short-run low volumes involved at the scale-up stage. Building a bespoke database compliant with 21 CFR part 11 to handle records can be a lengthy activity, particularly when compared with the pace of setting up paper-based systems.

Managing paper records generated by the manufacturing process can be challenging, putting storage and recall burdens on a manufacturer. Companies scan these documents soon after completion to reduce this burden. But the destruction of originals is risky, and the recall and integrity of e-records must be checked before destruction.

Pilot manufacturing helps optimize the journey of a drug delivery device to clinical trial. It’s not without its own challenges, but synchronizing manufacturing process and device design development, partnering with experts, having a plan for producing components that’s representative of the final production process, and keeping a handle on records puts you in a position to maximize pilot manufacturing’s potential.

References

Connect with CDP

For more on how to navigate pilot manufacture and bring drug delivery devices to clinical trial with confidence, contact Cambridge Design Partnership.

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December 21st 2021
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From medical devices to monitoring endangered species – 25 years of innovations improving lives

For 25 years, we’ve had one goal: to improve lives through innovation. To mark our first quarter-century, we asked some of our partners to talk about their personal standout projects. Their answers reveal how CDP innovation has built a better future for thousands – from facilitating treatment for breast cancer patients, to monitoring wildlife and detecting poachers in the most remote landscapes.

web_cameo_Visica Bringing breast cancer treatment into the physician’s office

Sanarus Technologies’ Visica 2 uses extremely cold temperatures to scarlessly destroy tumors. We completely redesigned this cryoablation system, enhancing performance and facilitating treatment in the physician’s office. Our advances reduced consumable cost by ten times and equipped our client with a strong IP position. Visica 2 was created to treat benign tumors – but it has since demonstrated impressive efficacy in clinical trials for malignant tumors, too.

“Our work on the Visica 2 breast cancer cryoablation system still excites me years later. We doubled performance and drove down costs, and clinical trials continue to prove the astounding efficacy of this no-scar, 30-minute procedure. Then there’s the human part: Sanarus Technologies’ chairman and CEO, BJ Hardman, shared her own Visica 2 treatment story, bringing to life the impact we’ve had on thousands of patients.” As stated by our Head of Medical Therapy.

 

web_cameo_Pulpex Groundbreaking sustainability project addressing plastic waste

Pulpex, a collaboration between Pilot Lite Group and Diageo PLC, is a patented, first-of-its-kind pulp packaging innovation. Renewable, recyclable, and biodegradable, Pulpex enables brands to completely rethink their packaging proposition. CDP set up an automated, short-run manufacturing line, helping to move this innovation from early concept to reality.

Chris Houghton, Head of FMCG: “Breakthrough innovation is what I’m most passionate about – pioneering new ground to improve lives. Tackling single-use plastic is a major challenge facing our generation, and our work with Pulpex promises to provide an alternative that’s better for the environment, encouraging consumers and society to live more sustainably.”

 

 

 

web_cameo_QpocPoint-of-care PCR COVID-19 testing instrument

In the early days of the COVID-19 pandemic, our team of mechanical, electronics and software engineers, as well as manufacturing and regulatory experts helped QuantuMDx develop their Q-POC point-of-care diagnostic instrument, which detects COVID-19 within around 30 minutes using PCR. Using our short-run manufacturing capability, we produced the first batch of instruments which were deployed to hospitals for COVID-19 testing studies.

Dan Haworth, Head of Diagnostics: “We worked at speed to develop QuantuMDx’s point-of-care molecular diagnostic device from an early prototype to a complete product for CE-IVD marking. We turned our meeting rooms into bustling labs, prototyped and tested over 100 design changes, and manufactured the first batch of 45 Q-POCs for QuantuMDx in little over 16 weeks. This was an extraordinary team effort and an emotional project from start to finish – one that our team is immensely proud of.”

web_cameo_zsl Satellite-enabled monitoring protecting endangered species

The Zoological Society of London’s Instant Detect 2.0 satellite-connected system monitors wildlife and detects poachers in the most remote and unconnected landscapes. The military-standard system is battery-powered and backpack-portable, so it can be deployed anywhere.

Head of Healthcare Insight & Strategy: “We created something with enormous conservation potential. Not only does it guard endangered species, but it can also monitor wildlife health, climate change, and the impact of ocean plastics.”

web_cameo_klarus Complete therapy management with adherence built-in

The Klarus drug delivery system improves the outcome of medical self-injection by eliminating the burden of everything a patient needs to think about, such as storing the medication at the correct temperature, dealing with sharps waste, and ordering repeat prescriptions.

Clare Beddoes, Head of Drug Delivery: “This shows how patient-centered design can change lives by considering every aspect of self-injection. Not only does it have the potential to improve medical outcomes, but it’s a more environmentally friendly solution, decreasing the waste normally linked with disposable autoinjectors.”

web_cameo_voke Taking a complex drug delivery device to market

Kind Consumer’s Voke is a smoking cessation product designed to imitate the experience of smoking regular combustible cigarettes while administering a pharmaceutical formulation. It’s a licensed medicine and a safer alternative to smoking.

Wade Tipton, Head of Manufacturing and Quality: “CDP quickly stepped into this project when the launch was at risk, overcoming complex engineering problems to gain regulation and take the device to volume production.”

Ben Illidge, Head of Tobacco Harm Reduction: “Our engineering expertise helped bring to market a product that went on to become the first nicotine inhaler to obtain a product license from the UK Medicines and Healthcare products Regulatory Agency (MHRA).”

web_cameo_biscuit Novel approach to energy management

Biscuit’s AI-powered smart building system monitors and controls building infrastructure to maximize comfort and minimize environmental impact. Its sensors report on essential parameters: energy consumption, temperature, humidity, air quality, pressure, VOCs, sound pressure, motion, and light levels.

We spend much of our lives in buildings, and they add up to nearly 40% of global CO2 emissions. Helping companies develop and deploy new products and technologies that help with the global need to decarbonize is always a ‘must-take-on’ challenge for us, and one where we can really help our clients succeed.

web_cameo_avon Smart packaging illuminating consumer behavior

Miniature sensing technology inside the dispenser of Avon’s ANEW Reversalist Infinite Effects Night Treatment Cream tested if users would rotate it every seven days to stop their skin from adjusting to the regime. The smart packaging trial revealed valuable insight about the intended product use experience when applied in a real-world context, and additional unexpected opportunities for innovation.

web_cameo_bloodhound Steering wheel to push the limits

Bloodhound’s goal was to break 1,000mph in a land speed attempt, inspiring a whole new generation of engineers along the way. Our role was to produce a titanium 3D-printed steering wheel to precisely fit the driver’s hands with custom controls for throttle, rocket boost, communications, and brakes.

Jez Clements, Business Development Leader: “In this project, everything got driven to its limits. It was a completely one-off experience: we got involved with schools, gave talks on 3D printing, and got to see the development of the car up close.”

Our clients trust us to identify, design, and build innovations that drive their success. Want to learn more? Explore our work.

Noga Sella & Dan Mayhew discuss why people with dyslexia can make great innovators
By Dan Mayhew and Noga Sella
October 6th 2021
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Dan Mayhew

Senior Laboratory Technician

Noga Sella

Consultant Physicist

Dyslexia Week: “We make great innovators”

Dyslexia Week takes place from October 4 to 10 this year and is centered on the theme of invisibility.

Dyslexia’s common, with one in ten people believed to have it – but because dyslexia itself isn’t visible, it’s not immediately obvious who does.

To raise awareness and bust the many myths about this learning difference, the British Dyslexia Association has asked people to share their experiences.

Senior Lab Technician Dan Mayhew and Consultant Physicist Noga Sella discuss the challenges of working from home with dyslexia, and why people with dyslexia can make great innovators.

How does dyslexia impact you?

Dan: I mainly have issues around written communication, so report writing can take longer, and my written work needs additional reviews. The lack of face-to-face interactions in the work-from-home age means written language has become more critical, making exchanges harder.

Noga: I lost my ways of communicating when we all started having to work from home because of the pandemic. Being able to speak to someone in person, and see their non-verbal communication, like facial expressions and gestures, are so helpful to me. Suddenly, everyone switched to using emails and messaging. Video calls are better than written messages, but then you’re up against unwritten protocols. For example, are you allowed to just call someone out of the blue, or do you have to set it up beforehand? It’s been hard finding a way to work with people all over again. I think the more you use video calling like you’re going over to someone’s desk, the better.

What encouraged you to study science?

Noga: When I was nine years old, I fell in love with space after visiting The Royal Observatory in Edinburgh. Yes, dyslexia makes learning harder, but reading and writing aren’t the only ways to learn. Immersive activities are a great way to get children with dyslexia into science, or any topic.

Dan: Both of my parents are involved in STEM subjects, but my main inspiration was visiting the Science Museum in London as a child and finding out Lego then was made from oil. The practical aspects of chemistry and a more ‘applied’ course at university really encouraged me to follow my science passion.

What do you enjoy about working in innovation?

Noga: I enjoy working in science within industry, as opposed to academia. In academia, there’s pressure to write fast and well. Industry lets me do my innovation without having to fight against my dyslexia as much. For example, I can put my graphs in PowerPoint and explain them verbally.

Dan: I love the ability to chuck out traditional ideas and come out with new products and services that can improve the daily lives of billions of people worldwide.

Why does innovation need (more) people with dyslexia?

Dan: People with dyslexia tend to be highly creative, think outside the box, have good pattern recognition, be picture thinkers, and see the bigger picture. All these traits are great for innovation.

Noga: Innovation needs diversity of all kinds. Diverse teams let you see things in different ways and catch things you might miss if everyone were to see things in the same way.

How can employers support people with dyslexia in the workplace?

Noga: Don’t take tools like spell check or searchability for granted. Twenty years ago, I wouldn’t have been able to search for something using a search term that had a spelling mistake in, so I couldn’t have been where I am now. Organizations can help by making sure people have access to the most up-to-date tools.

Dan: Things always start with education and awareness. We need to develop environments that adjust to the needs and skills of individuals.

Can you recommend any tips or tools you find helpful?

Dan: The writing assistant Grammarly is a bit of software that I find incredibly powerful. Also, being open and honest about your disability can be a real asset. I’ve found that being genuine to a potential employer about your disability builds trust.

Noga: My piece of advice would be that asking is better than presuming. Don’t be shy to talk to me about my dyslexia. It took me a while to feel comfortable discussing it, but now I’m happy to, especially if it helps a child with dyslexia realize that if one path doesn’t look possible, there are always others.

About dyslexia

The British Dyslexia Association defines dyslexia as a neurological and learning difference that impacts how people process information. It primarily affects reading and writing but can also have an influence on someone’s ability to absorb information and their organizational skills.

Dyslexia and science: Busting the myths

Dyslexia occurs across the range of intellectual abilities and many dyslexics show strength in reasoning and visual creativity. Biophysicist Jacques Dubochet, who picked up the Nobel Prize in Chemistry in 2017, speaks openly about how dyslexia impacted his early education, as does molecular biologist Carol Greider, who won the Nobel Prize in Medicine in 2009. In an interview for The Yale Centre for Dyslexia & Creativity, she said, “Perhaps my ability to pull more information out of context and put together difficult ideas may have been affected by what I learned to do from dyslexia.”

What can everyone do to help?

As Dan and Noga say, change starts with awareness. The British Dyslexia Association’s website is a good source of information and offers advice on how to make life easier for employees and colleagues with dyslexia. Tips include:

  • Record meetings (rather than emailing a summary).
  • Give additional time to digest information, for example by sending materials in advance of a meeting.
  • Use different formats to convey information, such as diagrams and flowcharts.
  • Provide hard-copy resources on colored paper (find out which color helps the person read best).
  • Give verbal as well as written instructions.
References
DC to DC converter design
By Finlay Knops-Mckim
June 30th 2021
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Finlay Knops-Mckim

Consultant Electronics Engineer

DC to DC converter design – Don’t blow your fuse (and other lessons)

With a vast range of off-the-shelf and feature-rich control ICs available, the selection and design of DC to DC converters is a superficially simple process.

But even with these highly integrated parts and design resources there are still many common pitfalls that can lead to Electromagnetic Compatibility (EMC) or thermal nightmares, blowing budgets, timescales, and the occasional fuse in the process.

I’ll share a few of the most common “gotchas” that electronics engineers will contend with early in their careers. We’ll dodge the complex calculations here, but there are excellent resources such as “The Art of Electronics” that can provide a deeper mathematical explanation of the issues at hand.

Medical device or arc furnace? Context is key

You wouldn’t use a trailer truck to commute to work, nor would you use the family car to ship potatoes to a supermarket. Both are vehicles but, clearly, they operate in different contexts so have different strengths and weaknesses.

The same logic applies to switch-mode converters and controllers. A quick glance at the cover page of any switcher datasheet will often reveal potential use cases. This is not just marketing: if a switcher is intended for industrial machinery or large server farms, it is quite likely that its EMC performance faces different limits to those marketed at consumer or healthcare devices. For example, while higher noise limits in industrial settings liberate chip designers to focus more on power efficiency by maximizing switching speed and slew rate, this can also increase emissions.

Excessive switcher noise can lead to poor performance of analogue circuitry, and in severe cases can interfere with the function of nearby devices. So, while those efficiency figures might be tempting, using the switcher in a compact medical device could lead to months of work to achieve compliance in EMC test chambers.

Lesson: Use parts in the context for which they are designed. Parts targeted at industrial applications may lead to issues if used in consumer or medical devices.

The heat must go somewhere

So, you’ve found a very neat five-amp switcher with a 3x3mm footprint that is 90% efficient? Sounds perfect for your space-constrained, high-power design. Except you’ve just plugged it in, and it cuts out after ten seconds at load. This is less than ideal. The problem is that, even at 90% efficiency, the switching losses at 5A are enough to make a 3×3 chip quite toasty – so much so that the thermal cut-out is operating. You might have been fine if you had a large copper flood to take the heat away, but this is a space constrained design so of course you don’t.

Lesson: Always consider the thermal design of a high-power system. Even if a small switcher is electrically capable of high currents, it may require substantial heatsinking that wipes out any size or efficiency benefits.

Evaluation modules are there to help

Datasheets are an important resource for correctly integrating a switcher design into a larger electronic system, but they are also a company’s marketing collateral, and can mask certain “gotchas” in product performance.

They do not guarantee that your design or use-case will play nicely with the chosen parts. Evaluation modules (EVMs) provide a less theoretical way of confirming that a part is fit for purpose, and further provide a “best case” performance benchmark given exactly the right implementation.

Taking an EVM along when performing pre-compliance EMC tests is a quick way to confirm that the chosen part is not going to be an emissions nightmare in the final design, and similarly if the EVM overheats, your design probably will as well.

Lesson: Buy in an EVM for your chosen switcher part and perform a set of tests that represent the final use case. If you have problems at this stage, it’s fair to say you should pick a different part or modify your design to mitigate the issues.

Saturation current is not standardized

If your switcher’s primary inductor becomes saturated, the efficiency of the system will rapidly plummet, and it will likely lose regulation or overheat. Most switcher manufacturers helpfully include the necessary inductor current calculations to enable you to make the correct part choice; however, the inductor datasheets can themselves be misleading.

Saturation current is universally defined as the current at which inductance decreases by a certain percentage, but different manufacturers use different percentages. Wurth often take a 20% inductance drop to mean saturation, but other manufacturers may use a 50% or even 80% drop.

Careful consideration must be given to peak inductor current, not just expected output current. High efficiency switcher designs typically look to minimize switching time and thereby losses, but this inherently drives up peak inductor current (and also EMC emissions!)

Lesson: When specifying an inductor, check what inductance drop the saturation current parameter refers to. If 80%, then you need to design more current headroom into your system to maintain correct regulation. Pay attention to peak currents!

Switchers aren’t always best

Switchers are more efficient than linear regulators, so does that mean they should be used wherever possible? Not quite.

Look at the efficiency curves on the datasheet. See that bit where the efficiency curve falls off a cliff at low loads? If your mobile widget, for example, needs a 3V0 rail derived from a 3V7 LiPo, and spends most of its time in a micro-power sleep mode, your switcher will likely burn more power than an LDO in those periods when the load is not drawing much current. If you then add in inductor switching losses and quiescent current, you could end up throwing a lot more power away through trying to use an “efficient” switcher than by using an “inefficient” linear regulator.

Lesson: When designing power supplies for very low power devices, consider if a switcher is honestly the best option. Even low power optimized designs (such as Analog Devices Micropower ICs) may still yield worse results overall than a carefully specified LDO in a low power application, so a system level power budget analysis is a must.

Keep it (the high current path) simple

Switchers create circulating paths of rapidly switching high currents as part of normal operation. If you don’t carefully implement these paths, then the system is likely to radiate or couple excess noise to other parts of the system, causing yet more EMC issues.

If possible, design the converter on a single layer to avoid layer transitions by vias, and with short, low impedance paths between the diode, inductor, and capacitors on the output side, with similarly low impedance paths between the input capacitors and switch FET. The ground path between all these components should also be robust and low impedance. If using a four-layer board, placing a ground plane under the switcher can suppress coupling to other parts of the circuit, but make sure to follow layout guidelines for the particular part, as coupling between traces and ground can be relevant to operation and performance!

Lesson: Keep the entire switcher design compact, and keep the ground return path short and on the same layer if possible. Ground planes and careful splits can be useful for reducing coupling of the circulating currents into other parts of the system.

This is far from an exhaustive list of all possible design considerations for DC to DC converters, but hopefully it gives you some useful guidelines on what to look out for when embarking on a new power supply design, particularly for those at the start of their engineering career.

Here at CDP we employ a talented range of engineers across all disciplines who solve problems like these on a daily basis. If you are interested in joining our team, check out our vacancies in Cambridge, UK or Raleigh, N.C. USA.

If on the other hand you are experiencing these sorts of issues at your company, please do reach out to CDP to see how our business can help yours.