Is your Power Supply SOUR (Same Old sUpply Range) or SWEET (Super Wide and Effectively EfficienT)?

Determining an application’s optimal power solution can be a daunting task, even for seasoned Electrical or Analog Engineers and Facilities Architects. The challenge grows when the solution must not only meet the specific needs of a system but also operate efficiently across an entire facility. This is where the experience can turn SOUR (Same Old Supply Range) or become SWEET (Super Wide and Effectively Efficient), depending on the approach taken. RECOM offers novel solutions that combine design simplicity with high-efficiency power distribution. You can make sweet lemonade from sour lemons – but RECOM encourages you to build the universal factory of the future instead.

Traditional power supplies are either AC or DC input. Even so-called universal input power supply units (PSUs) are limited to 85–264VAC or 130–370VDC. Though supporting a wide range for EITHER an AC or DC input, these ranges are constrained and therefore limit what devices can be supported without extra, costly, intermediary power conversion. AC limits are at least defined to cover all ranges of mains inputs [1], but still constrain the application space because they cannot cope with lower AC or DC supply voltages.

When it comes to DC power, there is a much broader spectrum of needs because most loads ultimately require DC (some motors and inverters are the most prolific exceptions to the rule). Therefore, standards can be specific to a class of products (like the universal serial bus or Power over Ethernet-USB or PoE) or an application space or market vertical (like the high-voltage data center-HVDC). But standard or no standard, many loads and operating environments will need to support wider, perhaps even unpredictable or unknown, input supply voltage ranges. In general, support for sub-minimal voltages enables the load to operate longer in the case of line voltage sags (a.k.a. brownout), while support for voltages above maximum ratings enables protections for equipment and users.

Regardless of AC or DC input, and whether trying to support extended voltage ranges above or below nominal specification, there is also the consideration of driving maximum power supply efficiency (e.g. – minimal dissipated power loss) based on the loading condition. In other words, the input voltage level to a power supply or system has an impact on power conversion (a.k.a. commutation) efficiency, even if the load remains static on the output side. But most loads are also dynamic in their current draw [2]. To assess true performance, one must have and study the power solution’s Efficiency vs. Load curve, as demonstrated by the example in the figure below.


Why should designers limit themselves to the SOUR (Same Old Supply Range) when there is so much more potential available? The ability to achieve maximum flexibility in terms of cost, uptime, efficiency, and sustainability – across nearly any scenario, even when the supply voltage is unpredictable or unknown – is an invaluable asset for any Design Engineer, Factory Manager, or Facilities Architect. For example, a single power supply—not a product family or a configurable platform, but a truly universal solution with a single part number—supporting input from 24V to 240V AC or DC, opens the door to genuine universal compatibility and unprecedented energy optimization.

RECOM is the first to bring such an advanced product to market, redefining what it means to be “universally-wide-input” compliant. How the RAC15-K/WI enables SWEET (Super Wide and Effectively EfficienT) solutions to power the facilities and applications of the future will be explored in more detail later on.