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DCH010505S: Isolated DC-DC Converter for 27W USB-PD application

Part Number: DCH010505S


I am assessing the feasibility of using the USB Power Delivery Specification for a portable medical device application. The intent is to provide convenient charging through USB-C, using the 9V/3A specification. In this use case, the AC-DC transformer will be of unknown origin and quality, and therefore we must provide mains isolation within the device itself. We have used 1:1 DC converters in the past for lower power applications, and have had luck with integrated devices intended for this application (up to 500mA). 

I am having trouble finding an equivalent solution for the higher power USB-PD, 27W. Most of the isolated DC-DC converters that I've looked at require a step down in voltage or do not provide sufficient power output. I would be looking for an input voltage range of 4.5 - 9V. The output could be regulated down to 5V, or could be regulated after the isolation. 

I would appreciate any advice on this or any recommendations of products that might meet my needs. 


  • Hi Ben,

    Sorry we missed your question. Were you able to find an answer? If not, let me know and we'll help you out.



  • Hi Grant,

    Thanks for the reply. I've contacted 8 different DC-DC converter manufacturers and have come to the conclusion that an integrated solution to meet my requirements simply does not exist, largely due to the inefficiency of drawing 27W with a 4.5V input. I have since reduced my requirements to a 9-18V input @20W, for which a solution does exist. Voltage output can be 9-12V as this will feed a 2 cell lithium ion battery charging circuit and downstream buck regulators. 

    That being said, I am still interested in the potential to meet my original requirements, or at least to achieve the highest reasonable power with a 4.5V input. An alternative compromise may be 15W with 4.5V, meeting the lower PD rule. 

    If you have any thoughts, I would appreciate it. A custom design is not off the table, but it is certainly less desirable than a standard brick pre-qualified part. Not sure if I mentioned this before, but the device requires 2 means of patient protection, which equates to 4kV of isolation for this voltage range. 



  • Hi Ben,

    Thank you for your patience. Let me contact the team that supports this line of products. They should be able to answer your question within the next few days.

  • We do not have an isolated, 27W power module that meet your specs.

    For this type of output power you will probably need to do a discrete design.