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UCC21520: Latch-up

user5163865
Genius 3670 points
Part Number: UCC21520

Hi,

A customer has an inquiry about latch-up.

・Is there a possibility that the driver will be latched up?
If the driver IC has a COMS structure, I think there is a possibility that a surge may enter the IC due to the FET mirror, etc., and short-circuit the power supply on the secondary side of the IC. (= Latch-up) Could you tell me whether or not there is a possibility of latch-up occurring?

・Could you tell me what to do in case of latch-up?
　In order to release the latch-up, it is necessary to cut off the power supply on the secondary side of the drive power supply once.
Do you have any recommended countermeasures or application notes?

As far as I can see the data sheet, it seems that the input and output have diodes of 20V/30V respectively. But I can't find any explanation about latch-up protection, please let me know.

best regards,

Hiroshi

  • 0
    TI__Mastermind 22035 points

    Hello Hiroshi,

    Our expert on this part may be out of the office at the moment, he should respond within the next business day.

    Regards,

  • 0
    TI__Mastermind 18446 points

    Hi Hiroshi,

    This is always a primary concern for gate driver design, since all of our drivers have a CMOS output. However, high output current and negative transients on pins are the primary use case, so every effort is made to eliminate parasitic SCR structures from the silicon design.

    All of our high current pins have multiple guard rings, and shallow trench isolation is used around wells to eliminate a body path. I have injected -5V (a transient from a double pulse test, with tons of transient current) into the output of UCC21520, and have not created latch-up. The ESD diode, rated for 2W, is the limiting factor.

    I have never seen latch-up, since it is only one big CMOS, not an integrated circuit or even an op-amp. Your concerns are pre-emptive.

    It is much more important to protect the driver from transient supply overvoltage, which is usually related to high switch node resonance. External clamping diodes, snubbers, and series resistors are common in inverter designs, and it is important to think of everywhere overvoltage can enter the supply and try to have a circuit countermeasure.

    Best regards,

    Sean

  • 0 in reply to Sean Cashin
    Genius 3670 points

    Hi Sean-san,

    Thank you for your detailed explanation.

    Best regards,

    Hiroshi