External power supplies explained

Healthcare Technology


XP Power’s Senior Product Manager, Andrew Bryars, outlines everything you need to know about external power supplies. Packaged in compact cases, these power sources are specifically designed for a wide range of applications and offer convenient cost-effective time-to-market solutions. 

We offer a wide range of external power solutions to our OEM customers and our products are designed to high standards, fully tested and certified by external compliance laboratories. Formats include wall mount with fixed or interchangeable AC input pins or in the desktop style cases.


What is an external power supply?

External power supplies are conveniently packaged power adaptors for use in the home, office, or industrial environments. They are sometimes known as desktop, wall mount, plugtop or wall plug power supplies. Like any other power supply, these products will convert AC supply voltages to a safe low-level DC voltage used to power equipment or to charge batteries. 

Where are external power supplies used?

The application of an external power supply is virtually unlimited and provides a convenient format power source. Such power supplies can be found in IT applications, slim panel monitors, security systems, portable computing, instrumentation, device charging in communications and healthcare applications for example. Using an external power supply allows the end application to be smaller and lighter. 

What benefits do external power supplies offer users?

An external power supply removes the need for more complex embedded power supply application designs, taking the hazardous AC supply and heat generated energy outside of the application in hand. As a stand-alone power source, it must be fully compliant, safe and easy to use. This then removes embedded design complexity from the system to the external power supply.

How are external power supplies different from internal PSUs? 

External power supplies offer convenient packages that can connect directly to an AC outlet or can be connected via a cord. The packaging provides a functional design that is safe to handle, typically compact in size and adaptable to worldwide AC voltage sources. Power ratings are usually less than 100W but with advances in power supply design solutions (i.e. GaN), 450W is possible without the need for cooling or large case sizes.

When is an external power supply the best solution for my application?

External solutions will enable a shorter design cycle for system designers; all the hard work is done and packaged in the power supply, leaving a simple DC cord to connect. Space is then made available inside the end system to enable smaller, lightweight designs. If the power demand is relatively low, then the power supply can be wall mountable directly into the AC socket or in the desktop corded style perhaps for more power-hungry applications.

How do I choose the right external power supply for my application?

In some ways, your choice may be driven by aesthetics as well as technical functionality. Wall mount solutions offer neat packages with a choice of AC input pins for different countries or can be defined by user changeable AC pins. Black cases are standard but other colours such as white are also available.

Configuration options allow you to select the output DC voltage, the output DC connector style and AC input pin style. Moving to a desktop format will enable higher power ratings and flexibility to use standard AC cords for the input side. Selecting a Power Delivery (PD) USB-C output option can enable automatic DC output voltage selection when paired with suitable equipment. 


What else do I need to think about?

When you’re considering your application, make sure you choose ITE safety standard 62368 or, if you are designing a healthcare device, 60601 international standards. Also don’t forget that you may need to consider other country-specific safety standards.


 Please contact our technical support team for more information on our industry leading external power supplies.