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BQ76952: I want to release OCD protection using instructions from the HostMCU.

Sho Takayama
Intellectual 390 points
Part Number: BQ76952

Tool/software:

Hi 

Host MCU sets OCD2:Threthold and Delay and reads Safety StatusA.

Host MCU can detect OCD2 protection by reading Safety StatusA.

At this time, I would like the MCU to decide whether to release the protection.

(I don’t want BQ76952 to automatically cancel protection.)

Please tell me how to release the protection occurring within BQ76952.

Tnank you,

Sho

  • 0
    TI__Genius 17835 points

    Hello Sho,

    Section 5.2.2 High-Side NFET Drivers under Partially autonomous from the technical reference manual may be what you are looking for.



    However, if you are planning to use the pins as DDSG/DCHG functionality, ‘Partially autonomous’ would not be recommended as explained in this previous forum post: Further Clarification Regarding DDSG/DCHG Operation

    B    est Regards,
    Alexis

  • 0 in reply to Alexis_H
    Intellectual 390 points

    Hello Alexis,

    Thank you for your reply.

    I think that 'Partial autonomoous' is also the function to turn off the FET from the Host MCU.
    I would like the protection operation (turn off FET) to be performed by the BQ76952 alone.

    I want to detail the release conditions for protection within the MCU.


     When BQ76952 hasn't released the protection (USE Fully autonomous),  Can Host MCU force release the protection?
     In this time,  BQ76952 must restart detection of protection.

    Regards,

    Sho

     

  • +1 in reply to Sho Takayama
    TI__Genius 17835 points

    Hello Sho,

    With ‘Partial autonomous’, you can still have the FETs turn OFF autonomously and recover autonomously when the conditions are met, however, by having the FET control subcommands ‘disable’ the FETs as well, a signal is latched which blocks the FET from being enabled until the MCU ‘re-enables’ the FETs.

    This means that even if you send the ‘ALL_FETS_ON’ command, if there is still a fault, the FETs should not turn ON until recovery conditions are met. However, if the recovery conditions are met and there is a subcommand to disable the FETs, the FETs will not ‘recover’/turn back ON until it receives the ‘ALL_FETS_ON’ command from the MCU to ‘release’ the block created.

    Sho Takayama said:
     When BQ76952 hasn't released the protection (USE Fully autonomous),  Can Host MCU force release the protection

    When the device hasn’t released the protection (fully autonomous mode), the host MCU should not be able to forcibly release the protections unless you are in full ‘manual control’ which would require the MCU to be the ones to turn off/on the FETs themselves.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Intellectual 390 points

    Hello Alexis,

    I understood.

    Thany you.

    Sho