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LTC4015: coupling outputs of parallel units

Hello,

We have a power pack designed around the LTC4015. To increase the total capacity for some specific application we would like to couple the output of multiple units when discharging.

Is there anything we should consider?

Basically we want to couple the output Vsys of multiple units in parallel to provide more capacity at the same voltage. The maximum discharge current is well below what a single pack can deliver.

While currenltly not intended, would there be any issue to coulpe the Vin (charger input sides) of mulitple units?

Best regards,

Lo2

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  • Hi Lo2,

    The LTC4015's "ideal diode" PowerPath is an ideal diode OR of only the VIN and BAT sources. It will attempt to have at least one of these sources powering the load at a time. LTC4015 does not expect an external supply on SYS and this will result in a short from VIN or BAT to whatever is powering SYS from the other LTC4015 unit. This could result in your batteries being shorted together or other undesirable power combinations.

    You should find a way to power share that does not involve directly connecting SYS on two LTC4015 units. You  might use an external ideal diode controller.

    There's not really any issue with combining the VIN rails except that the LTC4015 does not have a SYNC pin to phase your input current pulses. You just need to make sure your input supply can handle the max combined load pulses between both units.

    Regards,

    Zack

  • Hi Zack,

    thanks for the fast reply.

    The input power supply is beefy enough to cope with the pulses, so I'll connect the Vin lines.

    For the outputs, can I use something like  one LTC4376 per pack I guess.

    The LTC4376 can do 7A, and the maximum output of all packs combined is limited to 6A, so even when the packs are not charged to the same level, it should work.

    Best regards,

    Lo2

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  • Hi Zack,

    thanks for the fast reply.

    The input power supply is beefy enough to cope with the pulses, so I'll connect the Vin lines.

    For the outputs, can I use something like  one LTC4376 per pack I guess.

    The LTC4376 can do 7A, and the maximum output of all packs combined is limited to 6A, so even when the packs are not charged to the same level, it should work.

    Best regards,

    Lo2

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