BQ27542-G1: Effect of a built in PTC Fuse in the cell to be monitored

John Newton94

Part Number: BQ27542-G1

I have a single cell that has a built in PTC Fuse for safety purposes. The fuse has DC resistance. As the supply demand fluctuates the cell voltage after the fuse will fluctuate.

What effect will PTC fuse have on the accuracy of the cell capacity readings?

Thanks in advance

over 5 years ago

0 Dominik Hartl11 over 5 years ago

TI__Guru 61006 points

If you know the DC resistance, you can add it to Trace Resistance (see TRM, 6.9.1 Trace and Downstream Resistance Compensation)

If you don't know the DC resistance (or it is variable from unit to unit), you can run learning cycles so that the gauge will add it to its internal resistance tables.

If you don't do any of these then the gauge will overestimate capacity (because it doesn't include this resistance in its capacity calculations), depending on predicted and actual load current.

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BQ27542-G1: Effect of a built in PTC Fuse in the cell to be monitored