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TPS65381 Specifications

Guilherme Farenzena
Prodigy 230 points

Other Parts Discussed in Thread: TPS61085

Gentlemen

We are developing a safety PLC, we are using microcontroller RM48Lx50 and as recommended power supply is made by the chip TPS65381
I have some questions and would like help from you:
What is the maximum current that the supports TPS65381 ?
Our backplane has 5V supply, but to start it is necessary to 5.8V,
I could use the TPS 65081 to elevate this tension?

Graciously

  • 0
    TI__Mastermind 23000 points

    Hello,

    We have forwarded the request to our colleagues in the TPS65381 team and will update with their response as soon as possible.

    Regards,

    Karl

  • 0
    TI__Genius 13810 points

    5v is not acceptable.

    I was struggling with this when I designed a board to supply the TPS65381 device from 5v backplane power in July, 2012.

    The 1.2v and 3.3v can not start. Even if it starts by lucky some time, the TPS will fall into the safe mode, which looks like a dummy regulator.

    Regards,

    Haixiao

     

  • 0 in reply to Haixiao Weng
    Prodigy 230 points

    Haixiao

    I know he does not accept 5V, but my question is if I can use a TPS61085
    to reach the 5.8V trigger.
    And what is the maximum current TPS65381 supports??



    graciously

  • 0 in reply to Guilherme Farenzena
    TI__Genius 13810 points

    The maximum current that TPS65381 can provide to different power domain is listed in the datasheet.

    The current that the TPS61085 needs to provide to TPS65381 depends on the load of TPS65381. Since it is a LDO from 6v to whatever voltages, a rough estimation is to sum all the current required from 1.2v, 3.3v, 5v domain. The MCU requires about 500mA, you can find the detail numbers in the datasheet. Assume it is 1A total, then the pin 6v of TPS65381 need to provide 1A, and the power is 1A x 6v , assuming 90% efficiency for the switching regulator in TPS65381(VBATT to 6v), your TPS61085 needs provide 1A x 6v / 90% =7watt power. TPS61085 is strong enough in this case.

    Regards,

    Haixiao