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bq24172 - Can batteries be charged and discharged at the same time

Cris Basden
Prodigy 30 points
Other Parts Discussed in Thread: BQ24172, BQ24170

Hi am using the bq24172 chip to charge a three cell 12.6v 6800mah to power my senior design project. We are using a bicycle generator to power our system meaning variable power. To avoid this all power will be drawn from the battery which powers a microcontroller which controls some gps/bluetooth  and lighting functions.

The bq24172 chip has power path management but becuase the power supply is variable we probably wont use this. I am wondering if it is possible to charge and discharge a battery at the same time?

In doing a google search I was not able to find any credible sources.

  • 0
    TI__Mastermind 32400 points

    You may need to use in addition to the charger a DC/DC buck converter for your microcontroller.  The converter will take its input from the SYS and regulate your micro controller input power.    

     

  • 0 in reply to Tahar Allag
    TI__Mastermind 32400 points

    Hi Cris,

     

    I may miss understood your question in the previous post.

     

    The bq24170/172 charges the battery in three phases: pre-conditioning, constant current and constant voltage then termination please see figure 19 for more details.

     

    The total input power from an AC adapter or other DC sources is a function of the system supply power and the battery charging power. Without Dynamic Power Management (DPM), the source must be able to supply the maximum system current and the maximum available charger input current simultaneously. By using DPM, the input current regulator reduces the charging current when the summation of system power and charge power exceeds the maximum input power.

     

    In case the system power demand exceed the AC adapter or the DC supply, the battery will supply the mismatch in power. Therefore, the current capability of the AC adapter or the DC source can be lowered, reducing system cost.

     

    Hope that helps!

     

    Thanks,

    Tahar

  • 0 in reply to Tahar Allag
    Prodigy 30 points

    Tahar. The question is whether or not the battery will be charged at the same time as it is discharging.

     

     

    I have a lithium ion battery pack with two dc terminals. One is the output and the other connects to the charger.

     

    The question is if i supply voltage to the charging terminal via the Bq24172/Bq24170 can I at the same time provide power to a microcontroller without a disruption in power Thank you.

     

    Please if you need me to explain more I will.

     

    Take a look at the product on this page. http://www.eforchina.com/v/73723

    Thank you Tahar!

  • 0 in reply to Cris Basden
    TI__Mastermind 32400 points

    Cris,

     

    Yes! You can power your micro controller and at the same time charge your battery. The IC uses a dynamic power management to reduce the charging current into the battery when the input power limit is reached to ovoid loading the input power supply.

     

    Figure 1,2, 3 and 4 provides different schematic on how to use this part.  

     

     

     hope that helps

    Thanks

    Tahar