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TPS65220: and Functional Safety

James Slade
Prodigy 10 points
Part Number: TPS65220
Other Parts Discussed in Thread: TPS65219, , AM6442, TPS65224-Q1

Tool/software:

Hello, 

I am working on a design that we are in the first stages for that will use an AM6442 processor, and I am in the beginning stages of design, now looking into options for power. The TPS65220 seems to have a lot of app notes pairing the two, but I am interested in the line of the datasheet that says "Functional safety capable" that doesn't exist in the TPS65219 datasheet. 

The more important question is, seeing that the PMICs can be run in a multi-pmic mode, I was wondering if there is any information on using two TPS65220s in parallel to eliminate a single point of error of having just one pmic powering the am64x.

We are shooting for a sil3 design, but that is a "nice to have" right now, so sil2 is the absolute requirement. 

 

Let me know!

-James Slade

  • +1
    TI__Expert 6225 points

    Hi James,

    Thank you for reaching out.

    TPS65220 is functional safety capable but not functional safety rated, meaning FIT rate calculation, FMD and pin FMA are available but functional safety certificate doesn't exists.

    The multi PMIC mode comes into helpful when there are more rails on SoC and peripheral that needs to be powered but a single PMIC has fewer rails. I am not sure if a duplicate PMIC powering single AM64x is a possible solution. You can check with AM64 team. 

    TPS65220 is not ASIL certified, but you can looks at TPS65224-Q1 for ASIL requirement.

    Sathish

  • 0 in reply to Sathish Vallamkonda
    Prodigy 10 points

    From an internal point of view, is there any reason why I could not have two PMICs with their outputs tied together feeding the am64? Assuming they are tuned to near the exact output voltages, if one fails will there be a problem with backfeeding? Or during startup would there be a problem with the startup timing due to the other PMICs also coming up/ would this interfere with a single PMICs ov/uv circuitry? 

  • +1 in reply to James Slade
    TI__Expert 6225 points

    Hi James,

    That is correct, the converters are not designed to operate in multi phase, any small difference in the offset voltage could have a difference in the output regulation voltage and could cause back feeding and damaging the circuitry.

    Sathish