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Original question:

TMS570LC4357: What is PMIC of TI for TMS570LC4357?

TMS570LC4357: Use of Programmable (Factory loaded) PMICs with Safety Critical TI Controller TMS570LC4357

Kirana Kirana
Prodigy 50 points
Part Number: TMS570LC4357
Other Parts Discussed in Thread: TPS65381A-Q1, TPS65313-Q1

Hi,

I am looking for a programmable (or factory loading) PMICs to use with safety critical TI controller TMS570LC4357. So my question is, Can I use programmable (factory loaded) PMIC for safety critical (DAL A) design?

If yes, could you please suggest a PMIC (programmable or factory loaded) which has min 3/4 buck (5V to 3.3V, 1.4V, 1.2V), 3/4 LDOs (3.3V, 2.5V, 1.2V) and 1 boost (5V to 12V).

Input voltage range is 1 to 5V.

Thanks,

Kirana

  • 0
    Prodigy 50 points

    Hi,

    Could you please let me know whether I can use other TI programmable PMICs for safety critical design (with safety processor TMS570LC4357)? I have seen some TI programmable PMICs which have multiple buck/boost/LDOs per my requirement but I am not sure whether I can use them for safety critical design (with safety processor TMS570LC4357)?

    The PMIC which you have recommended does not meet the processor core current requirement (also per E2E posts on the same topic) and also does not meet the no. of buck/boost/LDO channels requirement per previous post.

    Thanks,

    Kirana

  • 0 in reply to Kirana Kirana
    TI__Mastermind 20590 points

    Hi Kirana,

    As you know, the functional safety system requirements are at system level.  There are many ways to use power management ICs to reach the necessary diagnostic coverage (DC) and architectures to meet a specific applications DC and safety goals.  The TPS65381A-Q1 is a PMIC that was designed as a companion chip to use with the TMS570 MCU family.  It has specific features and functionality to help support functional safety applications and has safety documentation available to help customers analyze it's use in their specific application.  We have other PMICs with functional safety features, functionality and documentation in our portfolio.  Also, you can always mix in a functional safety PMIC, plus discrete rails, supervisors and other functions as well to build up the necessary power tree for your application. It also depends if all the rails are used for safety related uses in the application or if some are safety related and some are not. 

    The link above will take you to the PMIC selection section of our website and it can help you find a PMIC that might make sense in your application.  You didn't list current needed so the best is if you spend some time on the PMIC site and consider which rails are safety relevant and not and what current levels you need.  With input voltage you listed as 1 to 5V range and all rails are higher than 1V it would seem you will need a pretty robust boost front end depending on the total current you need in the system, that requirement also contrasts your list of necessary rails where only 1 boost (from 5V to 12V) was listed.    You can see if there is a single or maybe a combination of PMICs that will help you build a power tree suitable to your application.

  • 0 in reply to Scott Monroe
    Prodigy 50 points

    Hi Scott,

    Thank you for your response!

    I would like to know how can I use programmable PMIC (PMICs with I2C or SPI interface) for safety application? Is it okay to use programmable PMIC for safety application?

    Thanks,

    Kirana

  • 0 in reply to Kirana Kirana
    TI__Mastermind 20590 points

    Hi Kirana,

    Most of our devices for functional safety have a mechanism to "lock" the configuration after it is set so a mis-behaving MCU cannot change the programmable portion of the PMIC after it has been configured during known valid operation.   However for example the TPS65381A-Q1 which was developed for use with the TMS570 has some regulators for the MCU rails (core and IO) that are configurable or adjustable but only via hardware for that generation. For configurable ones we have for example CRC's and register locks so if the configuration is changed for any reason the fault is detected and the state machine for that specific PMIC will react as outlined for the device, normally in a way that will indicate to the system that the system has to go to its safe state.

    Best Regards,

    Scott

  • 0 in reply to Scott Monroe
    Prodigy 50 points

    Hi Scott,

    Appreciate your valuable inputs!

    Is the above info applicable to only safety relevant TI programmable PMICs? or for all the TI programmable PMICs?

    Thanks,

    Kirana

  • 0 in reply to Scott Monroe
    Prodigy 50 points

    Hi Scott,

    I understand per the E2E discussion in the link below that I need to use an external DCDC converter

    to supply core current of ~1A (1.2V PS) for TMS570LC4357 along with TPS65381. So if that is the case can I use any other programmable PMIC (as a one-chip solution and which can source high current) to power TMS570LC4357 without using TPS65381?

    https://e2e.ti.com/support/legacy_forums/automotive/f/26/p/358491/1286509#pi320995=2

    Thanks,

    Kirana

  • 0 in reply to Kirana Kirana
    TI__Mastermind 20590 points

    Hi Kirana,

    Various PMICs from TI over time and generations have different features and functionality so it is impossible to give an answer that fits all PMICs.  The PMICs that are part of the SafeTI program of device for functional safety all have features and functions that were implemented to help the customer achieve diagnostic coverage in their system.  It really depends on the functional safety standard and level within the specific standard the application is trying to meet.  For example in automotive the requirements placed on a power supply and diagnostic coverage of a power supply is very different in ISO 26262 from ASIL-A vs ASIL-D applications.

    For the specific case of the TPS65381A-Q1, the device has an LDO controller that is widely used with many of the TMS570 MCUs, however for the newer versions requiring higher core current and for thermal considerations the option is to use an external discrete DCDC with the diagnostic coverage still provided by the TPS65381A-Q1.    Using a PMIC with integrated DCDC for higher power applications is an option if they match up to your specific application power tree requirements and either provide the diagnostic coverages you need to reach your SIL or ASIL target or the necessary diagnostic coverages can be added at the system level. 

    The TPS65381A-Q1 with DCDC remains a cost effective, scalable solution for the TMS570.  However if you wanted to look at a couple of other PMICs that might work have a look at the TPS65310A/311-Q1 and maybe the TPS65313-Q1.  Those are the PMICs that come to mind which much higher current capability and multiple buck converters or controllers.