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TPS61322: Short-circuit protection operation of TPS61322

Y.Ottey
Mastermind 6145 points
Part Number: TPS61322
Other Parts Discussed in Thread: TPS61070

Dear all,

I would like to ask about Short-circuit protection operation of TPS61322

Our customer considering the TPS61322 has asked about the short circuit protection behavior of the TPS61322.

When I check the data sheet, it is written as follows

If the output short circuit condition persists, is it OK to keep the above data sheet condition?
Or does the switching operation stop after some time?

Best Regards,

Y.Ottey

  • 0
    TI__Mastermind 46905 points

    Hi Y.Ottey,

    this device doesn't support short circuit protection. what is the input/output condition, i would suggest other devices

  • 0 in reply to Jasper Li
    Mastermind 6145 points

    Dear Jasper

    Thank you for your reply.

    I understand about your answer.

    If the over current condition persists instead of the short circuit condition, do you repeat the operation of the above data sheet?
    I think they work in the following order:
    ①When the inductor current exceeds the limit value, the low side switch turns off.
    ② When the current limit of the low-side switch (or high-side switch) is exceeded, the low-side switch turns on.
    ③ The overcurrent condition continues, so the low-side switch turns off again.
    I think that the above steps ① to ③ will be repeated.

    Regards,

    Y.Ottey

  • 0 in reply to Y.Ottey
    TI__Mastermind 46905 points

    Hi Y.Ottey

    the first step is correct. but in the second step, the high side will be off if the inductor current is 200mA lower than current limit.

    however, if the VOUT is lower or equal to VIN, the inductor current would be not lower than (current limit-200mA). The high side FET would be always on.

  • 0 in reply to Jasper Li
    Mastermind 6145 points

    Dear Jasper

    Thank you for your reply.

    I understand about current protection of TPS61322.

    "this device doesn't support short circuit protection. what is the input/output condition, i would suggest other devices"

    You previously answered as above, but do you know of any device with short circuit protection that can be used for the following conditions:

    Vin = 3V
    Vout = 3.3V
    Iout = 0.1A

    Regards,

    Y.Ottey

     

     

  • 0 in reply to Y.Ottey
    TI__Mastermind 46905 points

    Hi Y.Ottey,

    The TPS61070 is closed to this application.

  • 0 in reply to Jasper Li
    Mastermind 6145 points

    Dear Jasper

    Thank you for your reply.

    would like to propose the TPS61070 to our customers.

    Also, returning to the topic of TPS61322, there are additional questions to ask.
    " if the VOUT is lower or equal to VIN, the inductor current would be not lower than (current limit-200mA) .The high side FET would be always on."
    As mentioned above, is it possible that the inductor current value may exceed the current limit if Vout is the same as Vin or continues to operate with Vin smaller than Vin?
    Or if it hits the current limit, will it turn off like the low-side switch?
    (Is the current detection on the high-side switch only a function of seeing how much it has dropped from the current limit value?)

    Regardsa,

    Y.Ottey

  • 0 in reply to Y.Ottey
    TI__Mastermind 46905 points

    Hi Y.Ottey,

    the inductor current could be higher than current limit at VIN > VOUT condition. the low side switch will turn off, but high side FET can't be turned off to stop the current. this is nature behavior of a boost converter unless there is special circuit.