• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 271 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPSM33625: Regarding Inductor Loss in WEBENCH

nobuyuki_oda
Prodigy 80 points
Part Number: TPSM33625

Hello.

TPSM33625 was reviewed by WEBENCH. Do the "IC Tj" and "IC Pd" displayed in WEBENCH include inductor losses in the module? The data sheet temperature distribution (page 36) shows an IC surface temperature of 69°C. Even with WEBENCH under the same conditions, "IC Tj" was as low as 40.21°C and did not appear to contain it. I just don't see an entry for inductor losses anywhere.

  • 0
    TI__Guru* 78070 points

    Hello Oda-san,

    Thank you for posting.  My understanding is the inductor losses should be included when calculating IC Tj and Pd. Let me check with our Webench group expert, then get back to you.

    Thanks,

    Youhao

  • 0 in reply to Youhao Xi
    Prodigy 80 points

    Hello  Dear Youhao

    OK.Thank you for your support.

    Oda

  • 0 in reply to nobuyuki_oda
    TI__Guru* 78070 points

    I have send the message, please give us a few days to work on this. 

  • 0 in reply to Youhao Xi
    Prodigy 80 points

    It's been a long time, how are things going? I would like an answer as soon as possible.

  • 0 in reply to Youhao Xi
    TI__Expert 8365 points

    Hi Youhao/Oda-san,

    We are looking into it.We will keep you updated on this.

    Thanks & Regards,

    Praveen

  • 0
    TI__Intellectual 2290 points

    Hi -san

    We had the internal discussion within the team. Please find our observations below

     

    1. The effective RthetaJa given in datasheet is rated for 2.5A (25 degC Ambient). But this value can vary board to board (depending on the copper area, layers etc) and power dissipation (not linear variation)"

     

    1. On Webench RthetaJA is kept constant (22 degC/W) and will yield same temperature as 47 degC. Calculation below for your input condition.

     

    IC_Tj=(IC_Pd*RThetaJA)+Ta

     

    RThetaJA as per datasheet is 22 °C/W

    Ambient Temp = 25 °C

     

    IC_Tj = (1.06*22)+25

    IC_Tj=48.32 °C

     

    1. Now these calculations are dependent on assumption in point no 2 above. So these temperature are estimation for particular input condition.

    Looking at the thermal image and input condition the 61.8 degC value is correct and you can consider the same for your purpose. On Webench its and estimation with fixed RthetaJa and hence it will yield around 48.32.

     

    Hope above explanation helps. Kindly let us know if you have any further queries

     

    Thank you

     

    Best Regards,
    Sateesh A G