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TPS1H200A-Q1: How to paralell the devices for redundant needs?

Renato Barelli
Prodigy 80 points
Part Number: TPS1H200A-Q1

Dear all

We're developing a project that have this smart switch in order to limit the charge current over a capacitive bank, connected directly to a brushless blower.

Since we need redundant protection over this point, is it possible to parallel two devices? In other words, if one fails, the other is still there.

Would we need to 'separate' the two devices using OR diodes?

Thanks in advance

Renato

  • 0
    TI__Mastermind 34885 points

    Renato,

    What is the load current for this application and what is the device driving? Are there any inductive/capacitive elements here?

  • 0 in reply to Timothy Logan
    Prodigy 80 points

    Dear Timothy

    Thank you for your prompt reply. The idea is to limit the initial charge current in ~2A, so the empty capacitive bank doesn't trigger the power supplie's short circuit protection.

    Since this smart switch would deliver current to the capacitive bank and the critical load as well, it is necessary to have some sort of redundance in case of failure of the device.

    Regards

    Renato

  • +1 in reply to Renato Barelli
    TI__Mastermind 32650 points

    Hi Renato,

    You can parallel these devices and control them together or separately but apart from a reduction in R_on, the benefits of such a setup is minimal. This redundancy will help by providing a backup switch path but if there is a supply side failure, then the redundancy of the switch will not help.

    And if there is an event that damages one switch, it can very well damage the second one too. Usually for these back up topologies, we have a main supply and a backup supply (like super cap) that go to the same output.

    Another consideration for this is that the failure mode is not always "fail open" so in a failure event, the second switch may not be helpful as it will be shorted across by the damaged device.

    One possible suggestion I have is instead of having a parallel device, have an eFuse in series that will provide input power protection to the switch and make the power supplied to it more robust. The High side switch can then protect the load and drive inductive loads. Overall this system will provide a protection upstream and downstream and provide two switchpoints incase one device suffers a failure.

  • 0 in reply to Shreyas Dmello
    Prodigy 80 points

    Dear Shreyas Dmello

    I totaly agree with you in the point regarding the power supply failure, but today we do have a backup for this (battery that would keep the equipment working for a couple of hours).

    I'll think about the other points mentioned, specially about the possibility of having a good swith shorted by a bad switch. In this case the load would still receive current but there won't be any peak current limitation.

    I'm going to mark this as 'solved my issue', but any other information would be useful.

    Thank you guys

    Renato