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TPS24710: RMS current limiter

Mario Raffin
Expert 2405 points
Part Number: TPS24710
Other Parts Discussed in Thread: LM25061, TINA-TI, TPS24701

Dear All,

    I have an application where I need to limit the rms value to the load to 0.8A @5V.

I wonder if an hot-swap controller as for instance the TPS24710 could be used for this kind of application, using the timer pin to allow an over-current for a certain amount of time. 

Maybe it will not be exactly tuned on the rms current, since the equilibrium is reached when the time in which the current is greater than the imposed current limit is equal to the time in which the current is lower: T(I>I_lim) = T(I<I_lim). 

Do you know some other method to get a rms current limiter (able to react faster than a fuse, let say some millisecond and with a good accuracy (5%))?

Thank you in advance. 

  • 0
    TI__Expert 5940 points
    The TPS247xx series only provides CL/Pwr limit at power up. After that it is a threshold based timed shutdown (circuit breaker). Look at the LM25061 that will have a current limiter with timeout and see if it works for you. It will provide a set CL during normal operation.

    Brian
  • 0 in reply to Brian Daugherty
    Expert 2405 points
    Thank you Brian,
    sorry I forget to say that I need to break the circuit when an overcurrent is detected. But, since I would operate with the rms value the circuit breaker behaviour should be:

    - break the circuit after few milliseconds (let say about 10ms) with DC current greater than I_lim;

    - break the circuit with AC current absoption (>100Hz) when Irms > I_lim;

    So, I should allow peak current values greater than I_lim (I_peak = I_lim *1.41) without limit these peaks. In this regards the LM25061 is not suitable.

    Thank you for the support.
  • 0 in reply to Mario Raffin
    Expert 2405 points
    Hi, I found a good solution using the TPS24701. The simulation, using TINA-TI, confirms that I can achieve my goals:

    - break the circuit after 5 milliseconds with DC current greater than 0.8A;

    - break the circuit with AC current absoption (>100Hz) when Irms > 0.8A;

    - keep the output ON with AC current absoption, when Irms < 0.8A and Ipeak = 1.13A (i.e. 0.8*1.41) ;

    - break the circuit immediatly with DC or peak current greater than 2A;