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UCC256303: OCP Inquiry

Cedrick
Expert 8270 points
Part Number: UCC256303
Other Parts Discussed in Thread: UCC256403

Hi,

Good day.

Our customer uses the UCC256303 and they have this question, can you please help us?

have some doubts about the OCP features. OCP 1 is an instantaneous protection, and OCP2 and 3 are based on  average values with 2ms and 5ms constants. I understand, if any of these limits are reached, gate signals are shutdown, and the converter will restart after a 1 second time interval


Thanks,

Cedrick

  • 0
    TI__Mastermind 26225 points

    Hi Cedrick,

    OCP1 will trip after 4 consecutive switching cycles where ISNS is greater than the OCP1 trip threshold of 4.03V typical. OCP2 looks at the average of the ISNS signal where the input going into the averaging block is ISNS when the high side gate is on and 0V when the high side gate is off. The amount of time this averaged ISNS voltage must stay above the OCP2 threshold is 2ms typical. OCP3 functions in a similar way to OCP2 in that it also looks at the averaged ISNS voltage. The averaged ISNS voltage must stay above the OCP3 threshold for 50ms in order for OCP3 to trip.

    OCP1  is primarily used to react to a short circuit event and shut down quickly. OCP2 and OCP3 are similar to an overload protection that have a slower reaction time.

    The response to OCP1, OCP2 and OCP3 are the same. The controller will stop switching for 1s. After 1s, the controller will attempt to soft start.

    I would also like to mention that we have a newer version of this device called UCC256403 that includes some improvements to the feature set:https://www.ti.com/product/UCC256403

    Please let me know if this addresses your questions regarding OCP in UCC256303.

    Best Regards,

    Ben Lough