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BQ24232: Charge tolerance / error in datasheet

Part Number: BQ24232

Hi,

I have a question about the charger current factor K. The datasheet figure 8 and 9 seem incorrect. With 3.3k, the typical charge/precharge current should be 264mA/27*mA, but the graphs show 300/30. Could someone confirm if the graph is meant to show typical and what the error is? (also it says A instead of mA).

*I can’t see anywhere where it specifically says what the precharge current is but im assuming it is set by Kpre / Riset?

The graph is close to what the currents would be if k was worst case (max), 295mA/32mA, but still a bit higher. I want to confirm that the min / max K values (797 / 975 AOhm) are correct? As we want to set the charger close to 1C as possible for the battery, but without it being too high on a charger with high K.

Also, are there any distribution curves for the spread of K value? And is there any option of getting a part number with a closer tolerance of K value? Eg +/- 3%

Many thanks,

Michael.

  • Hi Michael,

    Thank you for catching the unit error. The graph is showing a programmed fast charge current within specifications of the K factor. We will see about changes to show the more typical charge current. The specified min and max K values for fast charge and precharge are gathered through validation and are correct.

    The BQ2407x family of devices is a pin to pin device that has a tighter current factor range. We cannot provide any distribution curves. 

  • Hi Anthony,

    Thanks for the reply. no worries about the curves.

    For the graph though, unless im missing something it is not within specifications of the K factor. I make it K = I*R = 0.3A * 3.3kOhm = 990. 

    So my question was whether the specification for Kmax was 975 per the electrical characteristics (and there was some error in the graph), or actually the graph is correct and Kmax is 990

    Regards,

    Michael. 

  • Hi Michael,

    Ah it would seem that you are correct and I had misjudged the axis on the graph. According to internal records, the Kmax value of 975 is correct. I will look into the issue with the graph and will update when this is understood.