Have you ever wondered how the military powers all their equipment? It’s not as simple as we have it – can’t just call the power company and boom, there was light. There are power supplies in virtually every military electronic system.
These devices come in all shapes and sizes. On matter functionality, it’s not that different from their commercial counterparts. They too have advanced power conversion solutions like AC/DC, DC/DC and other configurations.
How Different Are They?
The main difference between defense power supplies and their commercial siblings has been reliability. See how annoyed you get when there is a power outage? Well, imagine that in the military.
It is no longer simply a matter of inconvenience but potentially catastrophic failure and loss of life. Military power supplies were designed with a long mean time between failure as the main goal being delivering years of trouble-free operation.
What the Scene Is Like Today
The standard has remained reliable, with their MTBF being way higher than those of their commercial counterparts. On top of that, they are being upgraded every two years – just like consumer electronics I might add.
Every upgrade renders previous generations obsolete. This spells out obsolescence and availability issues. For long term reliability, the ability to recognize pending failure has become very important.
When it’s all said and done, military grade supplies have to meet specific requirements. These requirements include detailed guidelines for selecting components that are part of each supply not to mention a rigorous set of design rules to ensure manufacturability.
Let’s look at some of these guidelines:
Guidelines for Military Power Supply
Part Selection and Design
Part selection is a very important step in designing defense power supplies. All components that will be part of the product have to be approved and qualified by the manufacturer for use in any military system or be qualified for the application by the manufacturer of the power supply. This process serves 2 purposes:
- Establish that a stable source of supply for the component exists and adequate control procedures are in place
- Prevent the usage of restricted materials that can degrade during normal usage.
Over time, life cycles of advanced power conversion solutions have dwindled in importance although that remains a requirement in military electronic systems. Military electronic systems must be replaceable or at least repairable throughout their lifetime. This places extra demands on military grade power supplies manufacturers.
Application Requirements
Different branches of the military have published detailed sets of requirements that establish what is to be expected of power supplies from all military systems deployed in the field. These standards focus on performance issues as well as the working environment which can impact reliability.
Input voltage conditions for tactical military applications cover electromagnetic compatibility and input levels. Electromagnetic compatibility standards demand the amount of conducted RF energy the device must be able to withstand and still operate properly.
It usually is 40 dB or more. Commercially available filters that meet the requirements for commercial noise suppression cannot achieve this level of signal rejection.
With all that in mind, it is safe to conclude that each military power supply application must be approached individually to construct filters and maintain proper impedance matching characteristics to eliminate radiated noise at the input.
