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TPS65930 is abnormal at lower temperature

Other Parts Discussed in Thread: TPS65930, DM3730

Hi,all

    Power management:TPS65930

    Platform:DM3730

    The VMMC1.OUT voltage in the TPS65930  is 3.0V  at +25℃ when the systerm power on;but the VMMC1.OUT voltage drops to 0.4V after temperature fall to -25℃ and the systerm can not boot. who can give me a clue?

  • the part is guaranteed to work down to -40degC

    what normally happens in these cases is that the conditions around the TPS changes (L, C, etc..) Vs temperature and effects the normal behavior of the TPS.

    have a look at the main signals (V and I) during the start-up, gradually decreasing the temperature: at a certain point you will detect "the change" and understood the root cause.

    it could be (just one example) that the Cap (that normally increases as the temperature decreases) reduction leads to higher current inrust at the start-up and system latches; just an example...

    Vincenzo

  •  

    Hi,8103.swa3730_cb.pdfVincenzo

     Thank you very much for your reply,I can not understand what you said —"The Cap reduction leads to higher current inrust".
    .I send you my schematic, I would be very appreciated if you check it and give some advices.

  • sorry for the wording, I meant temperature decreases, caps increases, current inrush increase: this applies only if the issue is at the start-up!

    if the problem you are observin occurs when device is normally working and you reduce external temperature then we have to consider that the VMMC1.OUT (the droping voltage) is generated by internal LDO from VBAT and then track VBAT voltage as temperature falls...

    device performs as stated in datasheet, so if you test it separately it will perform as expected: if not there is something wrong / that is changing at the input (power IN) or at the output side (the VMMC1.OUT or VDD_MMC1 as you called it, supplies the U1C...what is the power consumption / the behavior of this part at low temperature? have you checked it?

    Vincenzo