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TPS62870-Q1: effective time

Shinji Tsuji
Genius 13889 points
Part Number: TPS62870-Q1

Hi team,

I plan to change VSET and SSCEN register while EN=Low at power up.

How long does it take for the register setting to be enable after I send write command to the register?

I think it will be single micro second. please advise if it takes some delay to reflect the changes for me to put some wait for EN=High.

regards,

  • 0
    TI__Intellectual 2040 points

    Dear Shinji, 

    Thank you for the enquiry. 

    Could you please elaborate on your question. Do you mean what is the time interval between when the register is set and it takes effect? 

    Also, since EN = low, it is worth mentioning that the DC/DC Converter does not operate, however, you can still read from and write to the device registers. 

    Please see section 9.3.4 in the data sheet

     
     

    Kind Regards, 
    Rameen

  • 0 in reply to Rameen
    TI__Genius 13889 points

    Hi Rameen-san,

    Yes. I would like to know the time interval between when the register is set and it takes effect.

    I don't think it takes >1ms but I would like to know if I need to insert a wait time before enabling the converter. 

    regards,

  • 0 in reply to Shinji Tsuji
    TI__Intellectual 2040 points

    Dear Shinji, 

    Please find the Enable delay time in the below, as tabulated in Table 8-5 in the datasheet. As seen below, the maximum enable delay time in 500 us. 



    For other I2C Interface Timing Characteristics, I recommend referring to Table 8-6 in the datasheet.

    Thank you. 

    Kind Regards, 
    Rameen

  • 0 in reply to Rameen
    TI__Genius 13889 points

    Hi Rameen-san,

    I would like to know the time interval between when the register is set and it takes effect, not the enable delay time. 

    Is that OK to immediately enable the device after the register is set? 

    regards,

  • +1 in reply to Shinji Tsuji
    TI__Intellectual 2040 points

    Hi Shinji, 

    SSCEN can be dynamically turned on and off without any delay.

    However, the situation for VSET is different.
    During softstart, no changes are allowed via I2C to the softstart time (SSTIME), vout range (VRANGE) or voltage setting (VSET). After setting a new output voltage while the EN pin is low, you should wait ~ >5µs to make sure the new set value is taken over.

    Thank you.

    Kind Regards, 

    Rameen