What are the advantages of isolated DC-DC converters?

Isolated and non-isolated dc-dc converters present one major difference between them. The big difference is that isolated converters usually feature two separated input and output circuits. It means that these two circuits are not connected to each other electrically in any way. On the other hand, non-isolated dc-dc converters usually have input and output circuits that are electrically connected to each other. The connection between the input and output circuits usually presents some challenges and safety issues that also form the main disadvantages of non-isolated dc-dc converters.

In this article, I will look at some of the advantages that are associated with isolated converters and how you can configure isolated dc dc converters to provide positive and negative outputs.

The advantages of isolated dc-dc converters

The first advantage that is associated with isolated dc-dc converters is safety. The isolation of the input and output terminals and circuits in isolated dc-dc converters usually prevents the input voltage from being transmitted to the output if there is some kind of internal failure in the circuits. This prevents the possibility of catastrophic incidences and that is why some governments make it mandatory for isolated dc-dc converters to be used in certain applications.

The second advantage of isolated dc-dc converters is that it is possible to configure the device so that it provides negative and positive outputs from both rails. The configuration requires a moderate level of expertise to accomplish it.

Lastly, isolated dc-dc converters are advantageous because they prevent the transmission of voltage transients on the input to the output.

How isolated DC-DC converters are configured to provide positive/negative outputs from plus/minus rails

isolated dc-dc converters can be configured so that they provide negative and positive voltages from a single device. In most cases, isolated dc-dc converters feature floating outputs where the case, output, and input circuitry are separated.

If you want the output to have a relative negative voltage, you will have to connect the output circuit reference node to the positive output. It is also possible for isolated dc-dc converters to be used with negative and positive input voltage sources provided the relative polarity of input is maintained.

Last words…

In a typical DC-DC converter, there is usually a regulator circuit that lets current to flow from input to the output circuit. The advantage of this is that it reduces the level of complexity of the device. This also reduces the size of the device and the associated price. However, there are specific situations that require the input and output circuits to be separated in a process referred to as galvanic isolations. Good examples of such situations are where safety is a major requirement. Comparatively, isolated DC-DC converters are usually safer when compared to non-isolated DC-DC converters.

Galvanic isolation is usually achieved through the use of a transformer to carry voltage and current between the gap between the input and output side. In place of a transformer, coupled inductors can also be used. This is usually the case in applications where the voltage and current are high enough to pose danger to human life.