FEATURE POWER ELECTRONICS
Medical power supplies - size does matter
Vox Power’s new VCCS300 power supply is capable of delivering 300W of output power in a tiny 2” x 4” footprint and is approved to the latest Medical (IEC/UL 60601) and ITE (IEC/UL 62368) safety standards. Here’s more on this latest offering
T
he medical device market is set for sustained growth over the next
decade and is a focus area for Vox Power’s new VCCS300 power supply. The fan-less design focuses on high efficiency and reliability to offer maximum flexibility during system integration. Critical elements to reducing the size
of a power supply are high efficiency and dealing with internal heat dissipation. Inefficiencies generate heat which if not removed effectively can cause excessive product temperatures leading to early failures or reduced long term reliability. When a 300W power supply is only 90% efficient it produces 33W of wasted energy in the form of heat which must be removed. However, when the same 300W power supply is 95% efficient it produces only 16.5W of waste heat. Excessive heat can be removed through any combination of natural convection, conduction or forced air cooling techniques. Vox power has chosen to concentrate its latest design efforts on conduction cooled products. The VCCS300 achieves efficiencies of
up to 95%. This high efficiency is accompanied by attention to circuit board layout and mechanical construction to ensure that heat generating components such as power switches and magnetics are assembled
26 FEBRUARY 2021 | ELECTRONICS
in a way which optimally balances heat distribution throughout the product. The use of advanced circuit board
materials increases thermal diffusivity providing for better and faster heat transfer into the integrated baseplate. The baseplate provides an interface which can easily connect to a metal chassis or a system heatsink to facilitate conduction cooling which allows delivery of up to 300W of output power at 40°C without any system fans.
FAN-LESS DESIGN Another key design goal was to offer a fan-less power solution to maximise flexibility during system design. As a mechanical component a fan is notoriously unreliable and noisy and no longer suitable in environments such as home healthcare and laboratories where silent high reliability operation is neded. The high efficiency and good thermal
management eliminate the requirement for a dedicated cooling fan which is very useful in compact higher power applications that have virtually no airflow. For larger systems which have a built-in system fan, the VCCS300 can deliver full power at 50°C with as little as 1m/s of system airflow. Meeting stringent medical EMC
standards in a power supply is always a significant challenge and many
Figure 1:
Vox Power’s new VCCS300 power supply
manufacturers tend to design a bigger filter to overcome this problem. Vox Power has spent many hours of research, circuit simulations, testing and optimisation to eliminate the sources of EMI noise. This has resulted in the VCCS300 having a very small EMI filter further facilitating size reduction whilst not compromising performance.
UP TO STANDARD The product meets class B limitations for both conducted and radiated emission standards (EN55011) with several dB margin throughout the full frequency range. Committing the time and resources to identifying and eliminating EMI sources throughout the design not only helps to reduce product size but also enhances reliability. The increased isolation, creepage and
clearance requirements for medical power supplies also inhibit size reduction. In the VCCS300 careful consideration was given to the design of mechanical insulators to achieve a BF rated output without impacting thermal performance or product size. The VCCS300 is a suitable power
solution for high-end next-generation medical applications.
Vox Power
www.vox-power.com
/ ELECTRONICS
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