• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 613 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

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

Benjamin Vespone
Prodigy 120 points
Part Number: DCH010505S

Hello,

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. 

-Ben

  • 0
    TI__Intellectual 1965 points

    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.

    Best,

    Grant

  • 0 in reply to Grant Falkenburg
    Prodigy 120 points

    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. 

    Thanks,

    Ben

  • 0 in reply to Benjamin Vespone
    TI__Intellectual 1965 points
    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.

    Best,
    Grant
  • 0 in reply to Grant Falkenburg
    TI__Mastermind 28020 points

    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.