Power Supply Optimization: Weighing The Benefits Of Custom Vs. COTS

When sourcing low- and high-voltage power supplies for either military or commercial applications, system design engineers must choose between commercial off-the-shelf (COTS) products or units built to custom specifications. However, misunderstandings abound regarding the cost of each option — in terms of both initial price and total cost of ownership — as well as delivery timelines, ease of integration, and real-world performance.

Understanding the pros and cons of COTS versus custom power supplies helps engineers make timely, defensible decisions about the products they implement in their projects. This knowledge is particularly consequential in military applications, where size, weight, power, and cost (SWaP-C) requirements usually are inflexible.

A commercial application is more likely to be set up in a controlled environment, where operating space and power draw are not as critical. Form factors tend to be typical (standardized, even). Conversely, military applications often require unique form factors to ensure proper fit on the platform, precise weights to maximize flight longevity, and strict center of gravity requirements, as well as near-infallible reliability to preserve operation in scenarios where human lives are at stake. Each application is different; what remains constant is that power supply parameters already have been figured into the engineer’s design.