This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25606: BQ25606 re-charge demand when VBAT is above recharge threshold

Part Number: BQ25606

Hello team,

customer has an application condition: for e-cig customer, when VBAT is above re-charge threshold, but lower than regulation voltage. e-cig consumer may use the e-cig and e-cig system will stop the charge process(at this moment, the adapter keep connected with battery). then, when consumer don't use e-cig, customer hope that the charger could re-charge, but at this moment, the VBAT is above re-charge threshold. 

What's the simple solution for this application demand? thanks.

Kerry Song

  • Hey Kerry,

    Just to make sure I understood you correctly, you customer wants to:

    1) Disable charge when VBATREG - VRCHG < battery voltage < VBATREG when the customer wants to use the e-cig. The adapter is still connected during this moment.

    2) Re-enable charge when VBATREG - VRCHG < battery voltage < VBATREG when the customer is not using the e-cig. The adapter is still connected in the situation as well.

    Is this correct?

    Just to clarify, in order to disable/enable charge on the bq25606, you will need to toggle the /CE bit. 

    Regards,

    Joel H

  • Hi Joel,

    When VBATREG - VRCHG < battery voltage < VBATREG, if toggle the /CE pin, BQ25606 should not be enable. Right? Only when VBAT<VBATREG - VRCHG, re- charge could start.

  • Hey Kerry,

    If you toggle /CE from LOW --> HIGH, in any range of battery voltage, charging will be disabled.

    Even if VBAT < VBATREG - VRCHG, it will NOT re-charge. This only happens if /CE is LOW (or toggled from HIGH --> LOW).


    Regards,
    Joel H
  • Hi Joel,

    Many thanks for you support.

    But the point is that, When VBATREG - VRCHG < battery voltage < VBATREG, if we toggled /CE from HIGH --> LOW, we can re-charge. But our device cannot realize it.

    So what's you simplest method to realize it? Thanks

    Best regards

    Kerry

  • Hey Kerry, 

    On it's own, the charger cannot enable and disable charge (apart from fault conditions) unless some external control drives it. 

    The problem is that if you want disable charging when the customer is using the e-cig, and re-enable it when they are not, you will still need some external control.

    If charging is always enabled, then charging will restart as soon as the voltage drops below the recharge threshold.

    Does your customer have some external controller? How do they plan on disabling charge when the battery voltage is the recharge threshold but below the regulation point?

    Regards,

    Joel H

  • Hi Joel,

    Thanks.
    Sure, system has a MCU to control the /CE.
  • Hey Kerry,

    The challenge here is being able to disable /CE when the battery voltage is above VBAT - VRCHG AND the customer is using the e-cig.

    The only two ways I can think of are either:  

    1. Comparator circuit to pull /CE high or low depending on battery voltage.

    2. Using an MCU ADC or external ADC to monitor battery voltage and drive /CE using MCU GPIO.

    Regards,

    Joel H