Design Concerns for Industrial Power Conversion…
Why matters?

Industrial computers (AKA IPC) are computer devices that apply to higher standards for specific scenarios such as medical, automotive, military, etc. For hardware designers to meet the requirements, “isolation” is a very popular topic. Why an isolated power converter is necessary when it comes to IPC design? An isolated power converter isolates the input from the output by electrically and physically separating the circuit into two sections which can prevent direct current flow between input and output. Typically, it is achieved by using a transformer. For example, powering your medical PCB without an isolation design, there is a greater risk for dangerous shocks or surges through the power supply and into your device, potentially harming the user and even the patient!

Commonly, industrial applications are very different from that used in consumer and mass-market designs. In industrial applications, the voltages, currents, and power levels are much higher. There are additional thermal and electrical ruggedness requirements, and strict regulatory mandates are in place for active and standby. On-going operations must be monitored for feedback loops and fault detection. Therefore, an understanding of isolated vs. non-isolated power design is all about designer and user safety.

Isolation Basics & Benefits
Isolation in terms of DC/DC converters refers to galvanic isolation which means that there is no metallic/direct conduction path between two parts of the circuit. The isolation will always present a barrier between the input stage and the output stage and may be required for circuit functionality, safety, or both. In short, it’s a physical and electrical separation between one section of a circuit and another.

The benefits of isolated design include,
1. Safety Compliance-
The most important reason that designers need to concern about. For converters powered from high and potentially hazardous voltages (such as ac-dc converters powered from ac mains) isolation separates the output from dangerous voltages on the input.

2. Breaking of Ground Loops-
Because the input and output of isolated supplies do not share ground, they can be used to break up ground loops. Circuits that are sensitive to noise can benefit from this by having their ground broken up and separated from noisy circuits that could cause problems.

3. Floating Outputs and Level Shifting-
While having a fixed voltage between output terminals, they don’t have a defined or fixed voltage relative to voltage nodes in circuits from which they’ve been isolated, and are said to be floating. A floating output may have one of its terminals connected to another circuit node to fix it to that voltage. This fact can be used to shift or invert the output relative to another point in a circuit.