Designing power supplies for Medical applications

Extreme personal safety and high quality standards are what is significant for Medical Power Supplies. There are very many applications and different types of electronics used in the medical field.

Everything from measurement and instrumentation equipments, packaging solutions, x-ray machines, life supporting machines to devices for medicine distribution, etc. The list is long and the power and voltage requirements are very different, but they all have in common that one has to pay attention to personal safety and quality.

Powerbox has been designing power supplies for medical applications for many years and have accumulated great knowledge and experience. That in combination with a management strategy of focusing on more complex design gives you as a customer access to state of the art technology. In
addition, we have selected manufacturing partners with full understanding for production of medical equipment.

What is a medical power supply? Basically the fundamental function does not differ much from industrial or telecom. It is the focus on the safety aspect that is distinguishing medical PSU.

The standards normally used during product development are
EN60601-1, UL2601 and CSA22.2-601.1.

In any design there are lots of design considerations that have to be handled and of course it is the same for medical PSU design.

To design for low leakage current and at the same time meet EMC standards one must use an intelligent strategy for thermal management, mechanical layout and filter design. If the internal heat sink is not connected to chassis ground the parasitic capacitor driven current will be kept at a minimum level. It is also the safety aspects during single fault condition that makes it an advantage to have the heat sink separated from chassis ground.

The physical positions of components are also very important
because it is not possible to compensate for a high EMI level by adding Y-capacitors. As capacitance must be low to ground the design of EMI filter requires special strategy resulting in increased size of common mode filter.

Leakage current must be analysed during normal and single fault
conditions. Single fault behaviour is of importance when selecting
topology and related components. That is verified during the design phase and it is also covered during FMEA (failure mode effect analyses).

All these aspects are well known by the Powerbox' engineering staff and considered during the design phase.

It is very important to have a close contact between the power
supply designer and designer of the medical system to get the most optimum solution. Quite often mechanical requirement is what is being underestimated.

If you contact Powerbox designers in an early stage of the project, the fundamentals of good and safe design can be guaranteed.

Powerbox offers fully customised medical power supplies in a wide range of applications. The experience covers the full power range and low voltage up to several tens of kilo volts for many medical applications such as X-ray and dialysis.

The medical power supply range offers the open fame/enclosed and external version. The Products features modern Switch mode topology, low leakage current and Universal 85-264Vac inputs. A range of output voltages is available from single to multiple output power supplies. Power ranges from 25Watts up to 650Watts.