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TPS7B82-Q1: short circuit questions

Peter Xu
Expert 6020 points
Part Number: TPS7B82-Q1

Tool/software:

Hi team,

My customer has some question about TPS7B82-Q1.

1. They want to know short-circuit protection response time. It means the time from the short circuit to MOS turn off.
2. They want to know the short-circuit protection mechanism and whether the working state in the protected state directly cuts off the output or is it similar to the pulse of the hiccup mode, if it is the hiccup mode, what is the time of each power-up?
3. How long does it take to recover after the short circuit occurs?

Regards,

Peter

  • 0
    TI__Guru 50025 points

    Hi Peter,

    I'm working on some other simulations for this same device, and I hope to get to this before I leave for the U.S. holiday next week. Does middle of next week work for them?

    Regards,

    Nick

  • 0 in reply to Nick Butts
    TI__Expert 6020 points

    Hi Nick,

    Customer needs these parameters asap.

    Could you tell me the exact time for the result? Then I can manage their expectations.

    Regards,

    Peter

  • 0 in reply to Peter Xu
    TI__Guru 50025 points

    Hi Peter,

    Understood. I am waiting on the answers to some questions I had for the other simulations and have not heard back, so I will work on this one. I will send you the results by end of Wednesday next week (U.S. time). 

    Regards,

    Nick

  • +1 in reply to Peter Xu
    TI__Guru 50025 points

    Hi Peter,

    1. I want to clarify first that the MOSFET does not turn off during a short-to-ground event; the main control loop is just taken over by the current limit control loop and regulates current instead of voltage.
      1. I ran a simulation at -40C and 125C, and at the process corners. In all cases the current was regulated to the current limit in 30us.
    2. The behavior during a short is as described in 1. This will be the case until the device heats enough to enter thermal shutdown, where the channel will be closed and the output current goes to 0A. The time until the device attempts to turn on again is dependent on the environmental conditions - the board layout and ambient temperature will determine the rate of cooling and subsequent turning on of the channel. 
    3. For the same condition as 1., all devices are above 95% VOUT (nom) in 87us from the time the short is released.

    Regards,

    Nick