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Original question:

BQ24610: BQ24610

BQ24610: BQ24610

hongwei duan
Intellectual 450 points
Part Number: BQ24610

Hello, I'd like to ask about the adverse effects when the input voltage is 0.3V different from the battery voltage.

  • 0
    TI__Mastermind 25800 points
    Hello,

    Being so close to the battery voltage can cause the charger to not operate. The converter needs a certain amount of headroom between VBAT and the input at VCC in order to operate, which is labelled as VSLEEP in the Electrical Characteristics table of the datasheet.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Intellectual 450 points
        Hello, I want to ask about the power input voltage I set is 18V, when the battery is full, it is 16.8V, the difference is only 1.2V. When I input the switching power supply is 18V/5%, then the lowest input is 17.1V. When it is full or not, it is the highest 15.6V. Then the reference voltage VREF (3.3V) is not available in that interval, and my STAT1, ST. AT2 is zero, so is it normal? The chip goes into sleep mode, the reference voltage VREF should not be hours.
            

        I would like to ask, the power input voltage of our project is 18V, the accuracy of switching power supply is 5%, then I set the battery charging voltage to 16.8V, can your company's chip meet my requirements?

  • 0 in reply to hongwei duan
    TI__Mastermind 25800 points
    Hello,

    As you stated, to use this charger the VCC voltage needs to be 600mV typical (100mV falling edge + 500mV hysteresis) above the SRN voltage, which will reflect the battery voltage.

    Now, based on your analysis if battery voltage is 16.8V maximum, it can be possible the charger will not turn on. If it does, also bear in mind that when current is drawn from your power supply, a voltage drop invariably occurs from your supply, through the resistive input line, input the charger's VCC. This means the charger could possible cycle in and out of the SLEEP condition as it becomes loaded during charging and unloading during SLEEP.

    So I cannot confirm or deny whether our chip will meet your adapter specifications because now other factors are involved such as charge current, maximum charge voltage, and input line resistance. But I can say exactly what I said before, if the input ever falls to VCC-VSRN <= 100mV or it cannot rise to VCC-VSRN > 600mV (once in sleep mode), you will not be able to charge your battery.


    Regards,
    Joel H