(Image credit: Bourns)
Isolated DC-DC converters are electronic circuits or electromechanical devices that convert electrical energy from one DC voltage level to another while being electrically isolated between the input and output. That isolation helps to ensure there's no direct electrical path between those inputs and outputs, making them ideal for use with EVs, portable electronics, industrial control systems and more.
Isolation is key when it comes to DC-DC converters for those applications, which works by integrating a transformer that transfers energy via magnetic coupling instead of the direct connection found in non-isolated converters. In some of those isolated converters, the primary and secondary circuits are separated for safety, which is why this design is widely used in high-voltage DC-DC converters. That separation also allows for breaking up ground loops to protect those circuits from noise.
There are several topology variations when it comes to isolated DC-DC converters, with the most common being the forward converter, which takes advantage of a transformer to increase or decrease the output voltage (depending on the ratio) and provide galvanic isolation for the load. With multiple output windings, it's possible to provide both higher and lower output voltages simultaneously.
There are also push-pull converters that take advantage of a transformer to change the voltage of DC power supplies. This is done by supplying the transformer with current from the input line by pairs of transistors. Isolated DC-DC converters can also come in full-bridge (or H-bridge), which switches the polarity of a voltage applied to a load, allowing motors to run forward and backward. Finally, there is the flyback converter, which can be used with both AC-DC and DC-DC conversion with galvanic isolation between the input and any outputs. The converter is essentially a buck-boost converter with the inductor split to form a transformer where the voltage ratios are multiplied and provide the additional advantage of isolation.
With that said, this is just a brief overview of what isolated DC-DC converters are and some of the applications that take advantage of their design. Those interested in learning more can attend Element 14's Isolated DC-DC Converters for the Design Engineer webinar hosted by Cathal Sheehan, Technical Marketing Manager at Bourns, and Jordan Ratcliffe, Marketing Program Senior Specialist at element 14. The webinar is expected to begin on January 14, 2025, at 2:00 PM, and spectators will have a chance to win one of two Multicomp Pro Digital Multimeters by watching the webinar, taking a small quiz and submitting a question to the Q&A portion, and commenting on the event page linked above.
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