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Battery charging-discharging at the same time

Hi All, 

I have one question, I'm using a solar cell to power a LiPo battery. This battery is giving power to a micro controller (MSP430) and to an additional circuit. At the moment when the battery is being discharged I have to recharge it using the solar cell -which is configured by the micro controller-. The issue is that I'm not sure if I can recharge the battery and give power to the micro controller at the same time. I could not disrupt the power because if I do that all the system would die. What can I do?

I google it but I did not see any credible source.

  • The current out of the battery charger will split between the battery and the load, assuming the load is connected directly to the battery.  If the load requires more current than the battery charger can provide, the battery will not charge.

  • Thanks for your answer, But what is prioriced? Charge? load? half and half?

    Thanks 

  • Can your charging source provide all the system current? If so then you could use a MOSFET-diode combination to switch the system current between the battery and the charging source. I am sure that there must be a TI application note illustrating this, but the one that I used is a Microchip one, AN1149. Take a look at that.

    It would also help to ensure that the lithium battery charges properly I think. Otherwise how do you know when the battery is fully charged? It is usually done by monitoring the current, but if the battery is supplying the system load then this would be difficult.

    Regards,

    Phil

  • TI makes charger ICs with the power path feature that provide a separate OUT or SYS rail as well as a BAT output.  The charger prioritizes system load over battery charge and monitors the battery voltage.  Once fully charged, the charger IC terminates charging.  If you can provide your input voltage, battery voltage and system voltage, I can recommend one of these chargers.