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Fast-Charging Trends and Challenges for Single-cell Batteries

J
Expert 1065 points

Hi
According to the training video "Fast-Charging Trends and Challenges for Single-cell Batteries" I have some questions I'd like to ask,

1.) According to this figure, fi the adapter is 5V, how to let Vbus become higher during operation, I mean 5V, 7V, 9V, 12V.

2.) According to this figure, how do you know when to stop the CHGR2 current, and why the CHGR2 will stop first.

3. What is the deglitch time mean and what problem can it make?

  • 0
    TI__Guru**** 166626 points

    Hi Jack,

    Regarding 1, the wall adapter to charger communication protocol shown is a proprietary one used by the adapter manufacturer.  Other protocols, like QC2.0 and QC3.0 use a different protocol with voltage pulses across the USB D+ and D- lines.  USB type C with its CX lines has yet another protocol.  The point is to increase the voltage so that the current reduces for the same power and results in lower V=IR losses across the adapter cable.

    Regarding 2, in the parallel configuration, one charger's regulation voltage is set slightly lower than the other so that one charger exits constant charging (CC) regulation and enters constant voltage (CV) regulation before the other.  Otherwise, with two voltage regulating sources trying to regulate the same node, there could be unstable oscillations.

    Regarding 3, deglitch time refers to a delay before a comparator that is comparing  a current or voltage to a reference voltage/current makes its decision.  It is intended to prevent a decision based on a transient/noise spike and allow the monitored current or voltage to settle to a steady state.  I refer to it as "time hysteresis".

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Expert 1065 points

    Hi Jeff
    Thanks for your kindly help.
    1.) Can you provide the dual charge and flash charge board to me, I'd like to see it.

  • +1 in reply to J
    TI__Guru**** 166626 points

    Hi Jack,

    Unfortunately, we stopped shipping a dual charger EVM but you can order 2 BQ2589X EVMs and manually connect them with wires.

    Regarding flash charger, there is a flash charger EVM at the link below but keep in mind that you need a smart adapter (or at least an emulated one with a processor) to communicate with the charger IC.

    https://www.ti.com/tool/BQ25871EVM-813

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Expert 1065 points

    Hi Jeff,
    Thanks.