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BQ24780S: Learn mode application

Part Number: BQ24780S

Hi Team,

I want to ask a question about the setting of register 0x3B bit [15:14], bq24780S

These are bits to set battery depletion threshold to let IC exit LEARN mode and boost mode

Here is the things

For example, my battery pack’s cut off voltage is 12V, full-charged voltage 17.8V

So it’s a 3V to 4.45V cell basically

Base on datasheet’s instruction, 3V/4.45Vx100%=67.41%

I will set bits [15:14] to [1:1] to avoid my battery pack cut-off during boost mode

But however for LEARN mode

This threshold is too high so that the battery is not discharge completely for gauge learning

So how to trade off it?

Best regards,

Hardy

  • Hi Hardy,

     

    In this case, please set the battery depletion threshold to '11' (70.97% of VREG). This will avoid over discharging your battery while still allowing the gauge to calibrate while the cell voltage discharges from 4.45 V down to ~3.16 V.

     

    Best regards,

    Angelo