How To Choose the Right DC-DC Converter For Your Specific Application

What makes a particular DC-DC converter well-suited to a given application? When looking at a DC-DC converter's specs, it’s important to keep in mind that almost every individual unit has been designed to be used in a specific environment at a specific load. Therefore, you must think of a DC converter's specs in terms of ‘where’ and ‘what’ factors, as in a) Where is the device designed to be used and b) What device was the converter designed to power?

What Environment Was the Converter Designed For?

During the design phase, where a DC-DC converter is planned to be used determines three of its primary characteristics:

  • Size
  • Ambient operating temperature range
  • Ruggedness

The first criteria is easy enough to understand – a converter must be able to fit wherever it is needed, whether that be the inside of a computer case or a larger wall-mounted radio system.

Ambient operating temperature refers to the conditions in which the DC-DC converter will be used: Will it be installed in a hot laptop case? Tucked under the hood of mining vehicle which is exposed to harsh winters and blistering summers? Sitting inside a climate-controlled lab? As you can see, the possibilities are endless, and understanding the temperature range helps you understand the nature of the design.

Finally, the ruggedness of a converter defines how well it can withstand repeated shocks (aka, how well it can take a beating). If a converter is installed in a product like a portable handset that will be constantly moving and jostled, the ruggedness requirements are higher than a converter installed in a stationary, vibration-free application such as an alarm system panel.

As you can imagine, compact and rugged converters than can operate in almost any temperature are far more expensive that converters designed to mount to the wall in a climate-controlled room with lots and lots of extra space. The final cost of your converter depends on where it's being used.

What Device Was the Converter Designed For?

Next, you want to consider what electrical specifications a DC-DC converter will be expected to satisfy – how demanding is the device that the converter feeds power. The “what” can also be broken down into three important considerations:

  • Available voltage
  • Voltage that must be delivered by the converter
  • Maximum output current capacity

These three factors play an important role in the physical dimensions of a DC-DC converter, whether it's a step up or step down converter. These factors also determine a converter's maximum power rating.

The electrical specification of a given DC-DC unit is also described by:

  1. How well it can maintain its rated output voltage in the face of fluctuating input voltage (known as “line regulation”).
  2. How well it can deal with a fluctuating load current in its' output range (known as “load regulation”).

Typically, a well-built converter will allow for its output voltage fluctuation to be just 0.1% or less of its specified output voltage level.

Finally, one cannot forget safety. In many situations, the performance of a DC-DC converter can have a direct impact on the health and safety of the user. The correct DC-DC converter must be capable of protecting people who are using the device from coming into harm’s way, even if the converter is overloaded or suffering abuse at the hands of a careless operator.

With so many DC-DC converter models out there, it’s clear that the sky is the limit when considering all of the various shapes, sizes, and capabilities that can be had. Whatever converter you select, it's a great idea to speak directly with the manufacturer of the converter about your specific application. Converter manufacturers have a tremendous amount of knowledge about use-specific performance – take advantage of it.

Author Ernest Herz works for SEC America, a manufacturer of high quality electrical conversion devices, including DC-DC converters. Learn more about SEC America's custom DC converter design and build services.