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BQ25620: BQ25620/BQ25622 Datasheet Error REG0x02 ICHG

Nicholas Zambetti
Prodigy 230 points
Part Number: BQ25620
Other Parts Discussed in Thread: BQ25622, BQSTUDIO

Hello, I'm fairly certain that the datasheet contains an error related to REG0x02 "Charge Current Limit" ICHG (highlighted in red)...

I wrote my test firmware program by using the depiction Figure 9-16, and the "Bit" column of Table 9-9, but I was not observing the POR default value of 1040mA. After some hours of head-scratching, I read the description column of Table 9-9 over and over again, and saw that the relevant bits of REG0x02 begin at bit 6, whereas the "Bit" column states it begins at index 5. I changed my code to begin at bit 6, and the correct POR value of 1040mA was shown.

This must surely be a mistake no?

What I am not certain about is if it is a 6-bit or 7-bit value. The maximum of 3520mA/80mA = 44 (0x2C) which can be represented in 6 bits, so I assume it is ok to treat it as a 6-bit field. For completeness, it would be good to know the actual size of ICHG though.

  • 0
    Prodigy 230 points

    I've just found the same error in REG0x10_Pre-charge_Control Register and REG0x12_Termination_Control Register ... where the table description column does not match the 'bit' column of the table, or the depiction. Off by one. As with REG0x02, when I update my program to use the bit locations in the description (rather than the depiction or the 'bit' column), the POR defaults match the output from my MCU.

  • +1 in reply to Nicholas Zambetti
    TI__Mastermind 32050 points

    Hi Nicholas, 

    Thank you for reaching out about your observation. What you highlighted in red is an error which has been identified and is set to be fixed in the next revision of the datasheet. We apologize for the inconvenience caused by the error. 

    For the BQ25620 and BQ25622 devices ICHG is a 6 bit value. The bit column of Table 9-9 should read 11:6. The description section is correct. 

    Additionally thank you for pointing out a similar issue in the bit column for REG0x10 and REG0x12 sections of register map. In both instances the Bit column has 1 too many bits. IPRECHG is a 5 bit value from 8:4 and ITERM is a 6 bit value from 8:3. The bits value in both Table 9-16 and 9-17 will be updated accordingly. 

    For future reference the BQ25620/22 GUI in BQStudio has a helpful visual reference to show the bits associated with each register setting as shown in the image below. 

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    Prodigy 230 points

    Hello Garrett, thank you for your confirmation and helpful reply. I've been evaluating the BQ25620 for a few days in the Rev.1 of a product I've been developing, and it's been performing well overall.