Electronics Weekly puts its questions to an industry figure: Adam Rawicz, managing director of power supply company Lambda Europe

A power engineer once told EW that the problem with power supply design is that you are up against the laws of physics so true innovation is all the more difficult. So what are the most important technology challenges in power supply design?
It is certainly true that the power supply designer needs to have an extremely good understanding of the physics of electricity. This places a premium on experience and tends to encourage an evolutionary - rather than revolutionary - approach to power supply development. But there is plenty of scope for innovation, as Lambda's NV product demonstrates. It's a matter of combining new components, topologies and thermal management to advance performance.

Is there a theoretical or practical limit on the power density achievable in the DC-DC or AC-DC supply?
Looking at the trends you can see an approximate doubling to tripling of power density in AC/DC power supplies every 10-15 years. The "state of the art" is about 12 -15W/cubic inch now.  The three main limitations on power density are getting the heat out of the power supply, the need to provide safe levels of isolation, and the mechanical problems of actually realising a design including connectivity. The main challenge many customers are facing today is not the size or efficiency of the power supply but more the ability to dissipate all of the heat generated within their system.

Semiconductor companies are keen to promote the importance of digital power systems, so what are the real impacts that digital control and comms bus technologies are having on power supply design?
I think Digital control in power supplies is a long overdue development. It will bring important application specific benefits, such as parts count reductions allowing smaller size, greater reliability, lower cost and easier adaption of control parameters to specific applications. Comms bus technologies allow advanced status monitoring and remote control of critical power supply parameters for high end applications. That can contribute significantly to a reduction of energy consumption.

What has been the biggest change in power supply design over the last 5 years?
Increased efficiencies leading to radical reduction in size - driven by evolutionary improvements in semiconductors and the engineering innovations to exploit them. I would say that is the biggest change in power supply design.

What are the benefits and challenges of designing world-class power supplies in North Devon?
It is a lovely part of the country but is perceived as being somewhat remote (although major improvements in road links mean that is not true any more). Therefore it can be difficult to attract people however the beauty of the area makes people reluctant to leave, which means we have an excellent and stable Engineering team who know each other well and work well together with all parts of the company.