Taking the pain out of power supply selection

Faced with thousands of power supply models, it can be hard to identify the right power supply for your application. Acopian’s Alex Karapetian looks at how to combat indecision.

Too much choice can be a bad thing, but there are ways to simplify power supply selection. The first filter is to look at the two main types of supply available: linear and switching.

Linear supplies
As the name suggests, a linear supply is one where a linear component is used to regulate the output. These power supplies have a relatively simple design and require few components. Linear regulated power supplies also have minimal ripple and output noise, also known as electromagnetic interference and radio frequency interference. Reducing electromagnetic noise emissions is important in equipment such as medical power supplies, audio devices, sensors and telecommunications.

Switching supplies
Switching power supplies, sometimes referred to as switch mode power supplies, regulate the output voltage using a high frequency switching technique that employs pulse width modulation and feedback. Here, power is supplied from the input to the output by turning on a switch until the desired voltage is reached. Once the output voltage reaches the predetermined value, the switch element is turned off and no input power is consumed.

Generally speaking, switching regulated power supplies are smaller and lighter in weight. For example, a 250W linear power supply would require 600in³ of mounting space and would weigh 26lbs, while a comparable AC/DC switching power supply would require 60in³ of mounting space and would weigh 2lbs. A linear power supply normally operates around 60 per cent efficiency for 24V outputs, whereas a switch-mode power supply operates at 80 per cent or more.

Form factor
Another thing that can help to narrow down power supply choice is the form factor and dimensions. Take a look, for example, at a few popular types designed expressly for mounting in 19in wide RETMA cabinet racks, a standardized frame for mounting multiple electronic equipment modules.

Where only minimal mounting space is available, Acopian’s narrow profile power supplies are a great fit. Choices range from high performance models to general purpose options with output ratings up to 150V, and up to 3.5A.

Where designs call for a power supply that must function for many years without risk of failure, redundancy can provide a solution. Acopian’s redundant power packages contain two identical power supplies with their outputs interconnected through a diode switching arrangement that will detect any fault condition, isolate it from the system output and pass only the output of the other supply with no interruption of output power during the transition.

Perhaps you’re looking for a programmable power supply? Acopian’s 1U family of programmable AC/DC power supplies is capable of wide adjust output voltages ranging from zero to five volts to zero to 135V and current capabilities up to 70A.

A custom fit
Acopian can also develop regulated power supplies to meet specific custom power supply challenges. Over the last 60 years, Acopian’s power supplies have been used in ground support for NASA, mission critical test equipment for Boeing, Raytheon and Northrop Grumman, in amusement parks to power rides and in stadiums and arenas to power audio and lighting.

Helping to speed time to market are easy-to-use tools such as the online custom power supply system builder. Through a series of intuitive steps, users can custom design AC/DC and DC/DC power supplies, high-voltage, redundant systems and unregulated power supplies. Custom designed units are offered in every physical configuration, shipped fully wired and 100 per cent tested within three to nine days.