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BQ25616: The OVP circuit, and the charge & system current

user4937122
Prodigy 120 points
Part Number: BQ25616
Other Parts Discussed in Thread: BQ24073, BQ25606, STRIKE

Dear Sir.

Could you help me with the BQ25616 and BQ24073 ?

I designed my charger with BQ25616,  it works well.

But to save the system cost and the space, I am checking the circuit again.

Q1:
I designed an OVP circuit for the BQ25616 and tested, Is it ok if I remove the OVP circuit for the BQ25616 ?
The input voltage of bQ25616 is max 16V.
I need to reduce BOM and space.


I am using a 1A adaptor.
The battery charge current is 1C and capacity of it is 850mA.
When the battery was fully discharged, it needs 850mA for charge at initial state, and to operate the system, it also needs max 800mA.
The adaptor current is lower than 1.65A(850 + 800mA).
After device works with 800mA, it entered into idle mode , the current consumption is 20mA in the idle mode.

Q2:
In this case, does the BQ25616 reduce the charge current to supply sufficient current to the system ?
and if the device enter into the idle mode, the BQ25616 supply 850mA of charge current to the battery again ?

Q3:
In this case, does the BQ24973 reduce the charge current to supply sufficient current to the system ?
and if the device enter into the idle mode, the BQ24973 supply 850mA of charge current to the battery again ?

Best Regards,Yoon.

  • 0
    TI__Genius 10385 points

    Yoon,

    I designed an OVP circuit for the BQ25616 and tested, Is it ok if I remove the OVP circuit for the BQ25616 ?

    This is fine. Short VAC to VBUS and float ACDRV.

    In this case, does the BQ25616 reduce the charge current to supply sufficient current to the system ?

    You are correct. The charger will always prioritize powering the system. This is described in the Dynamic Power Management section of the datasheet.


    and if the device enter into the idle mode, the BQ25616 supply 850mA of charge current to the battery again ?

    Correct.

    In this case, does the BQ24973 reduce the charge current to supply sufficient current to the system ?

    Yes
    and if the device enter into the idle mode, the BQ24973 supply 850mA of charge current to the battery again ?

    Yes

    Best Regards,

    Ricardo

     

  • 0 in reply to Ricardo
    Prodigy 120 points

    Dear Ricardo

    Thank you for your kind explanation.

    Best Regards,Yoon.

  • 0 in reply to user4937122
    Prodigy 120 points

    Dear Ricardo

    1.Could you review my schematic attached ?

    2.If I don't use the external OVP circuit, should I put a zener diode instead the OVP circuit ?

       One ESD diode was used . The Zener diode for the 3A is quite expensive.

    3. about the TS pin , I used the 10K pull-up/down. is it right ?

    4. I connected the /pg pin to one ADC pin of CPU, and the BAT pin to the other ADC pin of CPU.

       If a high voltage ESD(when  DC jack inserted or battery connected) is apply  to the BQ25616, can the ESD apply to the ADC of CPU through the /pg of BAT pin ?

    5. what is the difference between the BQ25616 and BQ25606 ?

        If the BQ25616 delivery time is long, I consider the BQ25606 as backup IC.

    BQ25616_sch.pdf

    Best Regards,Yoon.

  • 0 in reply to user4937122
    TI__Genius 10385 points

    Yoon,

    1.Could you review my schematic attached ?

    If you are using a 1A adapter, why set ILIM to 1.27A? Other than that, I see no major issues.

    2.If I don't use the external OVP circuit, should I put a zener diode instead the OVP circuit ?

    I strongly recommend adding the diode if you are forgoing the ACRDV circuitry.

    3. about the TS pin , I used the 10K pull-up/down. is it right ?

    If Hot/Cold is not to be used then replacing RT1 and RT2 is acceptable.

    4. I connected the /pg pin to one ADC pin of CPU, and the BAT pin to the other ADC pin of CPU.

    /PG will not ESD strike the CPU as it is not directly connected to the input, but rather the output of an input comparator. There is potential for BAT to result in an ESD strike to the CPU in the event of a hot plugged battery. It is your responsibility to design in protections to your CPU. If this is not desired we do offer chargers with integrated ADCs that can report BAT voltage.

    5. what is the difference between the BQ25616 and BQ25606 ?

    See the Device Comparison Table of the BQ25616 datasheet.

    Best Regards,

    Ricardo

  • 0 in reply to Ricardo
    Prodigy 120 points

    Dear Ricardo.

    Thank you so much for your explanation.

    I set the ILIM to 1.27, because I considered the 1200mA battery,  1.5 A, and 2.0A adopters  first.

    BTW, if the Adopter is 1A and ,   and the ILIM == 1.27A, and the peak  current == 1.5A,   is the 1A adopter damaged ?

    BRs,Yoon.