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BQ77915: Threshold of OCD and OCC

KIM
Intellectual 550 points
Part Number: BQ77915
Other Parts Discussed in Thread: BQ76942

Hi,

We would like to use the BQ77915 for the following application.

Discharging current = 10A max

Charging Current = 1A max

We want to set the OCD = 15A and OCC = 3A. We have chosen the BQ7791500.

The OCD1 threshold = 60mV. For OCD=15A, the Rsense = 4mOhm (60mV / 15A).

However, with Rsense = 4mOhm, the OCC current threshold = 15A (60mV / 4mOhm). The OCC of 15A is much higher than the typical 1A charging current. This does not make sense for overcurrent protection in charging.

Does TI have other BQ77915 version with lower OCC threshold? Or will TI provide customized BQ77915 with different OCD, SCD and OCC thresholds?

Thanks,

Kim

  • 0
    TI__Expert 3425 points

    Hi Kim, 

    The datasheet will have all our released catalog of parts, if none of the variants of the BQ77915 are feasible then we would recommend a monitor as the BQ77915 is one of our only multi-cell primary protection IC's. 

    While we do try to add more variants periodically, it is a huge effort and requires a significant business justification to go down that path. 

    Because of this, we would recommend the BQ76942 monitor which is highly configurable for precise thresholds for a host of protection features that build upon those of the BQ77915. BQ76942 has autonomous cell balancing and fault recovery in addition to various power modes and communication protocols (I2C, SPI, and HDQ) 

    If you can provide more details on the cell configuration and FET topology (high-side or low-side) we can recommend a more specific part. However, given that Bissell caters to the cordless and portable vacuum space the BQ769x2 device family will likely be a good fit. 

    Best, 

    -Luis Torres