• State TI Thinks Resolved
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 51 views
  • Users 0 members are here
Support feedback
Options
Options
Related

TPS25940-Q1: Current Limit Timing

Alberto Gonzalez Marcano
Prodigy 455 points
Part Number: TPS25940-Q1
Other Parts Discussed in Thread: TPS25947

Tool/software:

Hello,

How long does it take for over-current to regulate current to desired limit during an over-current event? My customer has ILIM set with a 22Kohm resistor. 

Thanks,

Alberto Gonzalez 

  • 0
    TI__Mastermind 38275 points

    Hi Alberto,

    The response time for normal OCP is usually few ms. We don't have it in the datasheet for this device but this can be evaluated by customer. The response time for SCP is given in the datasheet (200ns)


    This waveform is showing OCP response and then TSD during OCP and then auto-retry.

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    TI__Prodigy 455 points

    Hi Arush,

    What can we do to characterize the OCP more accurately? Do we at least have a range?

    Ford needs this timing spec for their I2T characteristic.

    Thanks,

    Alberto 

  • 0 in reply to Alberto Gonzalez Marcano
    TI__Mastermind 38275 points

    Hi Alberto,

    Apologies for the delayed response.

    This parameter is not characterized during the validation of this device. We won't be able to provide you a number. Internal implementation for OCP response is based on comparator and current sense. The comparator response time will be typical 2us and current sense will also be 1-2us. So, I expect the overall OCP response time in that range of 4-5us (typical). I hope this helps. I would still recommend them to evaluate this. 

    Best regards,
    Arush 

  • 0 in reply to Arush Gupta
    TI__Prodigy 455 points

    Hi Arush,

    I am a bit confused now. Above you mentioned OCP is normally a few ms but in your latest message you say 4-5 us, am I missing something here?

    Thanks

    Alberto

  • 0 in reply to Alberto Gonzalez Marcano
    TI__Mastermind 38275 points

    Hi Alberto,

    Let me clarify this with an example.

    this is from TPS25947 datasheet. If you see the response time is 2us for that device. I had discussion with design team, and we expect ~4-5us response time. This is time for device to detect Overcurrent and perform OCP.

    For TPS25947, we also have another entry with current limit settling time (400us). We can expect similar time if customer wants to know time in which current will settle to ILIM value.

    I hope this clarifies this. It looks like in first reply I made a typing error. I wanted to write microseconds (for the response time).

    Best Regards,
    Arush