I'm doing a course project on electrical engineering subject. I have to use this specific DC DC converter ISL2412 XP Power DC DC converter. But before I can use it, I have to explain how does it work.

I can't find anything about it's operating principle. The only thing I found out is that it isolated type. So this type of DC DC converters has galvanic isolation, is that the main part of it that do voltage transform?

So the question is, what is the isolated DC DC converter operating principle?

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    \$\begingroup\$ You are literally buying a black box with these parts. I can make an educated guess as to which topology it uses, but without reverse engineering it will be difficult. \$\endgroup\$
    – W5VO
    Jun 7, 2016 at 3:45
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    \$\begingroup\$ @W5VO Russian school of experimentalism [I say with pride]. \$\endgroup\$ Jun 7, 2016 at 4:21
  • \$\begingroup\$ It could be an isolated flyback converter with an inductor-transformer. It could be a transformer-based isolated converter. Perhaps a forward converter, or a push-pull converter. \$\endgroup\$ Jun 7, 2016 at 4:44
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    \$\begingroup\$ How it does work is up to the manufacturer. But, many ways it MIGHT work can bne seen here \$\endgroup\$
    – Russell McMahon
    Jun 7, 2016 at 8:34

1 Answer 1


While it may not apply to the specific device from XP Power, application note slyt211 from Texas Instruments explains how small (<5W) isolated power converters such as the DCP010512 operate. Essentially, inside the converter, there is a set of switches and an isolation power transformer. The controller generates a waveform that allows for power to be rectified on the isolated side. An unregulated device has an internal diagram such as:

Texas Instruments Functional Block Diagram for DCP010512B

However, the ISL2412 you wish to use has regulated outputs. This adds additional complexity to the device. The LTM8048 datasheet shows how such a regulator could be implemented, along with the other switching electronics:

LTM8048 block diagram from page 8 of https://cds.linear.com/docs/en/datasheet/8048fg.pdf

For dual-supply operation, Murata's BEI15 Series includes a block diagram for regulated outputs:

BEI15 Series connection diagram from page 1 of http://power.murata.com/data/power/bei15.pdf

Further, Digikey reveals that this BEI15 Series module is not encapsulated, allowing you to see how components are arranged:

BEI15 Series module image from https://media.digikey.com/photos/Murata%20Photos/MFG_BEI15-Series.jpg

Here, you can see the control IC on the load side in the front-left of the module, the board-level transformer in the middle of the board with a snap-in ferrite core with the Murata logo, and two switching devices along with ceramic capacitors on the far edge of the device.

Finally, the Murata BWR Series devices includes a nearly complete diagram of a higher power (ca. 30W) isolated converter using synchronous rectification on the load side:

BWR Series simplified schematic from page 1 of http://power.murata.com/data/power/bwr33w.pdf

Additional references:

  • The DFC10 Series from Power One has a block diagram on page 48
  • This image of a SHHN000A3 Series converter from GE on Digikey
  • The DSP1 Series from Power One has a block diagram on page 2
  • This image of a PTB48510 converter from TI on Digikey
  • The IMX70, IMY70 Series from BEL has two block diagrams on page 3

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