• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 386 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS2492: TPS2492: Timing Capacitor and over current response time

Charles Cammarata45
Intellectual 270 points
Part Number: TPS2492
Other Parts Discussed in Thread: LM5069

Hello. I have 2 questions regarding the TPS2492

1. Is there a lower limit for the timing capacitor?

I would like to have an overcurrent response time around 5-10 microseconds, as I am using this to protect a downstream 20KHz PWM motor drive circuit. Is this something the part can achieve? I calculate that it will require around a 33-47 pF capacitor.

2. Does the device behave to actively current limit (regulate) or does an over current detection over the threshold simply activate the timer?

Thank you, CHarlie

  • 0
    TI__Guru** 105361 points

    Hi Charles,

    Thanks for reaching out.

    1A) Leaving the timer capacitor pin OPEN sets the lowest fault time period.

    2A) For an overload fault, TPS2492 device regulates the output current to the programmed value.

    BR, Rakesh

  • 0 in reply to Rakesh
    Intellectual 270 points

    Thank you Rakesh.

    So if I have the current limit set to ~3.8A by using a 12mohm Rsense resistor, based on the TI calculator I should never see more than ~4.6A n the output, give some for tolerances. Correct? How fast is the current limiting response?

    Thanks, Charlie

  • 0 in reply to Charles Cammarata45
    TI__Guru** 105361 points

    Hi Charles,

    Yes, including tolerances the current limit should not exceed 4.6A .

    Unfortunately, we don't have characterized value for the current limit response. The response speed varies with the gate amplifier overdrive which is proportional to the (VCC-SENSE) voltage. Higher the overdrive, faster the response.

    If you are particular about the current limit response, I suggest to use LM5069. The response time is 45us. Refer page-6 in the LM5069 datasheet for details.

    BR, Rakesh