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TPS22968: Using TPS22968 for charger multiplexing

Chris Schramm
Intellectual 590 points
Part Number: TPS22968
Other Parts Discussed in Thread: TPS22917, TPS22916, TPS22953, TPS2115A

Hi TI-Team,

will the TPS22968 work for connecting two batteries individually to a BQ24210DQCT charger IC? We will charge only one battery at a time and I don't know if there might be current flowing between both channels.

  • 0
    TI__Genius 10855 points
    Hi Chris,

    Thanks for reaching out on E2E!

    Can you elaborate on the configuration, or provide us with a schematic / drawing?

    In general, the TPS22968 does not have reverse current protection. Therefore, if there is voltage on the output of the device, the TPS22968 will not prevent current from flowing to upstream components. However, we do have devices that offer RCP. A good device for battery applications is the TPS22916 or the TPS22917.

    Thanks,

    Arthur Huang
  • 0 in reply to Alpha H
    Intellectual 590 points

    Hi Arthur. I‘m currently not on my desk, so I‘ll try to explain:

    We have two 3.7liion batteries. At any given time, one of them is only charging (secondary) while the other supplies output for the load. As soon as the secondary battery is fully charged, it will become the primary battery and charging the other battery begins.

    In scope here is only the power from one of the two batteries to the charger. I want to use a load switch to let the MCU control which battery is charged while the other is disconnected from the charger IC

  • 0 in reply to Chris Schramm
    Intellectual 590 points
    By the way, for load switching from battery to dc dc converter we‘re using TPS2115ADRBR but it has about 80mOhm and I think it‘s to much drop for charging. We‘ve designed the charger with MAX14714 (11 mOhm) but since all other parts are from TI I‘m looking for a replacement for the MAX as well
  • 0 in reply to Chris Schramm
    TI__Genius 10855 points

    Hi Chris, 

    Thanks for the clarification. You could use two TPS22953 in a MUXing configuration. The TPS22953 has reverse current blocking only when the device is disabled. Therefore, if the device is on, it acts as a bidirectional load switch. This could allow you to charge one of the batteries. Once the device is disabled, it will block reverse current. 

    In regards to a replacement for the TPS2115A, the lowest Ron solutions we have today would include two load switches. If the TPS22953 solution doesn't work in this scenario, you could try using two TPS22916 to reduce the quiescent current and shutdown current when the channel is not in use,

    Thanks,

    Arthur Huang

  • 0 in reply to Alpha H
    Intellectual 590 points

    Hi Arthur,

    I've decided to try a prototype with TPS2115A and confirm the voltage drop when the board arrives.

    Please let me know if you think the TPS2115A won't work (I'd have to stop production then).

    Thanks,
    Chris