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BQ79656-Q1: Maximum connection of the BMIC quantities

Part Number: BQ79656-Q1
Other Parts Discussed in Thread: BQ79718-Q1, , BQ79616-Q1

I hope to know how many BQ79656 BMIC can be connected using the daisy chain communication loop ?

Does it 12 BMICs could be connected each other as maximum ? or more ?

I hope to know this for BQ79656-Q1 and BQ79718-Q1.

Because I am looking for feasible BMIC for 250 cells based battery pack system as a series.

for example, when I consider BQ79656 for 16 Cells monitoring IC then it required 16 BMICs connection to cover 250 cells.

but, I don't know is 16 BMICs connection possible or not possible for BQ79656. 

  • Hi Yangsoo,

    The number of devices you can have in a daisy chain is limited by the number of addresses possible in a daisy chain. This would be dictated by the ADDRESS bitfield in either DIR0_ADDR or DIR1_ADDr depending on the direction of communication. 

    As the ADDRESS bitfield is 5 bits, this means 31 in a chain in a single direciton. 

    This would also apply to the BQ79616-Q1. 

    Best Regards,

    Anthony Pham

  • Dear Anthony 

    First of all, I am thank you for your reply and answers.

    When I checked "device address byte definition" in the data sheet for BQ79656-Q1.

    I can see it's range. it is 0x00 to 0x3F thru 6 bits so I understood 62 BMICs which is the maximum quantities in a chain.

    did I understood correctly for the BQ79656-Q1 ?

    and how about the BQ79718-Q1 ? I can't see it's data sheet from the website yet so I want to get answer for that from you again.

    at the last,

    Are there any data synchronization issues when I used 16 BMICs in a chain ?

  • Ohps correction! The ADDRESS bitfield is 6 bits, so this would be 63 devices in a stack. 

    Best Regards,

    Anthony Pham

  • Hi Yangsoo,

    Welcome to E2E!

    Oh for some reason this didn't show up when I was replying earlier. 

    You are correct, per my other reply. There are 6 bits of addresses so 62 devices can be in a stack. 

    Unfortunately, I'm not at liberty to answer any questions regarding BQ79718-Q1 on the public forum. You can request the datasheet on the product page. 

    Data synchronization does depend on components but as long as the recommended components are used, there should be no sync issues.

    Best Regards,

    Anthony Pham