Fundamentals of Power Supply Over Current Protection

As engineers we are often looking at ‘what if’ scenarios to ensure our designs work under as many application conditions as possible. For conditions under which our designs do not work properly, we at least do not want either our product to become damaged or our designs to damage something else. With power supplies one of the concerns often is “what happens if the output load current from my power supply exceeds the power supply’s current rating”. In this article we will discuss common methods employed in power supply designs when the rated load is exceeded.

Although we most often call them “power supplies” we normally are actually referring to “voltage supplies”. The difference between the two designs is an ideal ‘power supply’ will deliver constant power to a load regardless of the load voltage .

With power supplies one of the concerns often is “what happens if the output load current from my power supply exceeds the power supply’s current rating”. In this article we will discuss common methods employed in power supply designs when the rated load is exceeded.