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TPS27081A: Li-Poly Battery charging Isolation

Dharmesh Joshi
Expert 1785 points
Part Number: TPS27081A
Other Parts Discussed in Thread: TPS22998

Hi

We would like to isolate a Li-Poly Battery Charger IC+Battery from the remaining system circuit. 

The purpose of this isolation is when the battery voltage drops very low, we would like the charging to only charge the battery.

We would like to force this SWITCH OFF when the battery voltage is less than 3V and back ON once the battery is 3V+. If this is not possible we can manually control the Enable on this device using a toggle switch.

We have chosen to use TPS27081A, as we are currently using this device on various PCBs already and have them in stock.

Or is there any alternative solution? 

  • 0
    TI__Mastermind 19385 points

    Dharmesh,

    A could way of doing this would be to have a comparator output (such as a fast comparator on an MCU) hooked up to toggle the switch when the voltage dips below 3V (with some added hysteresis). In this case the TPS27081A would work without issue. 

    What would be the maximum voltage on the battery? You could use something like the TPS22998 if you need something simpler. 

  • 0 in reply to Timothy Logan
    Expert 1785 points

    Hi Timothy

    Thank You for your email.

    The max voltage of the battery is 4.2V.

    When the battery drops below 2.5V, the charge goes into a 10mA trickily , and if anything such a uC is powered it consume the charge and battery does not reapply recover. That is the reason for the switch is necessary.


    Is this comparator possible independently?