# Isolated DC-to-DC converter

Canonical URL: https://eloragrid.ai/symbols/isolated-dc-dc-converter
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: DC/DC ISO
Drawing use: SLD, Schematic
Reference families: IEC, IEEE / ANSI

A DC/DC converter with an internal high-frequency transformer that separates input and output galvanically.

## In plain English

### What does Isolated DC-to-DC converter mean?

An isolated DC/DC converter uses a high-frequency transformer between its input and output stages, so the two DC systems have no conductive connection. Isolation lets the output be earthed differently from the input, for example a floating battery bus supplying an earthed control system, or keeps a fault on one side from reaching the other.

### A simple example

Drawings show the DC/DC box with a transformer mark or a pair of coupled coils inside, or a vertical double line across the box. The isolation voltage is a key rating and should be written beside it.

### What the drawings help you do

The symbol alone does not state the test voltage or whether the isolation is functional or reinforced for safety. Those properties decide whether the output can be treated as a separated circuit, so they must be read from the product data.

### This particular reference

A DC/DC converter with an internal high-frequency transformer that separates input and output galvanically. An isolated converter separates input and output; a non-isolated buck or boost converter shares a common conductor.

### Terms

- DC: Direct current: electricity flowing in one direction.
- Winding: A coil of conductor inside an electrical machine or transformer.
- Normally open / normally closed: The contact state in the normal condition defined for the drawing.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Power topology selection and public topology tutorials](https://www.ti.com/video/series/power-topology-selection.html)
- [DIN-rail power supply, buffer, redundancy and UPS families](https://www.emea.lambda.tdk.com/uk/products/din-rail)


## What it represents

An isolated DC/DC converter uses a high-frequency transformer between its input and output stages, so the two DC systems have no conductive connection. Isolation lets the output be earthed differently from the input, for example a floating battery bus supplying an earthed control system, or keeps a fault on one side from reaching the other.
Drawings show the DC/DC box with a transformer mark or a pair of coupled coils inside, or a vertical double line across the box. The isolation voltage is a key rating and should be written beside it.
The symbol alone does not state the test voltage or whether the isolation is functional or reinforced for safety. Those properties decide whether the output can be treated as a separated circuit, so they must be read from the product data.

## How to read it

- A transformer mark inside the box shows isolation.
- Read the isolation rating rather than assuming safety separation.

## Information to show or reference

- State input and output voltages and isolation voltage.
- Show earthing on each side.
- Reference isolation class.

## Important distinction

An isolated converter separates input and output; a non-isolated buck or boost converter shares a common conductor.

## Facts

- Isolation element: High-frequency transformer
- Earthing: Each side can be earthed independently
- Key rating: Isolation test voltage
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [Power topology selection and public topology tutorials](https://www.ti.com/video/series/power-topology-selection.html) — Texas Instruments. Public power topology tutorials including isolated converters.
- [DIN-rail power supply, buffer, redundancy and UPS families](https://www.emea.lambda.tdk.com/uk/products/din-rail) — TDK-Lambda. Public DC power supply and converter family context.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.