• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 31 subscribers
  • Views 322 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.

TMCS1101: Hall effect current sensor internal DTI and reinforced isolation

Luca Ghislanzoni
Prodigy 110 points
Part Number: TMCS1101
Other Parts Discussed in Thread: TMCS1123

Hello,

we are planning to use the TMCS1101 for current sensing on the mains side (European 230V grid), to then read the output on a SELV side.

We have a cut on the PCB, running underneath TMCS1101 to further separate the two sides.

The complete device, including the TMCS1101, is then fully potted in polyurethane resin (for reasons other than electrical insulation, and rather related to the operational environment).

Putting aside  package clearance and creepage issues, which are dealt with separately as explained above:

internally to the package, for that particular material used, would the datasheet DTI =60um correspond to reinforced isolation suitable also for 230Vac mains applications?

Many thanks in advance,

Luca

  • 0
    TI__Expert 6305 points

    Luca,

    The insulation used is rated for up to 600 V peak, or 424 V. RMS, so the 230Vac voltage you are considering should be fine. Here is the part of the datasheet from page 5 that gives this as well as some other insulation parameters: 

    You may also be interested in this technical article about DTI and insulation strength: https://www.ti.com/lit/wp/slla563/slla563.pdf

    Let me know if you need any more assistance with this,

    Levi DeVries

  • 0 in reply to Levi DV
    Prodigy 110 points

    Thanks Levi for the prompt reply.

    Indeed we had well understood the datasheet insulation specs. However those values, that you also mention, are fine for BASIC insulation, whereas we asked about REINFORCED insulation, which the sensor is NOT providing at 230Vac. 

    • It is clear to us that 230Vac reinforced isolation clearance and creepage for the soic-8 package would not be met
    • That is why we put those aside (dealt with by potting), and narrowed the question down to DTI only
    • We had also read the DTI pdf, but that does not help us if we do not know the dielectric strength of the material. Value that TI must instead know.

    Best regards

    Luca

  • 0 in reply to Luca Ghislanzoni
    TI__Expert 6305 points

    Luca,

    Thank you for clarifying for me, I will have to reach out to some of my team members to look into this question, I will work on it and get back to you at a later time.

    Levi DeVries

  • 0 in reply to Levi DV
    Prodigy 110 points

    Great, I'll look forward. I may add that we have also seen the TMCS 1123 Advance Information, a device which will provide certified reinforced isolation, but in our existing application that would draw too much quiescent current (10.5mA to 14mA), whereas the TMCS 1101 draws around 5mA only.

    Luca

  • +1 in reply to Luca Ghislanzoni
    TI__Expert 6305 points

    Luca,

    I'm glad you found the TMCS1123 as it is the only magnetic part designed for your situation. I am still waiting on our systems team for answers about the TMCS1101 insulation and will get back to you when I hear from them.

    Levi DeVries

  • 0 in reply to Levi DV
    TI__Expert 6305 points

    Luca,

    After consulting with the team, the TMCS1101 will not qualify as reinforced isolation for your application as the insulation will not meet the specifications for reinforced isolation.

    Hopefully the TMCS1123 could work for your application in spite of the larger quiescent current.

    Let me know if you have any more questions I can help you with,

    Levi DeVries