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UCC21520-Q1: SCHOTTKY DIODES AT PIN INA AND INB

Madhura Gogate
Prodigy 80 points
Part Number: UCC21520-Q1
Other Parts Discussed in Thread: ESDS302, UCC21550, UCC21520

Hello team,

Have seen references which have schottky diode at the input of INA and INB pins of a gate driver.  One is towards GND and one is pulled high to VCC.

Wanted to understand why these components are used and the considerations at the gate driver input.

Can you please help?

What are the example part nos. and key ratings to be considered?

Thanks!

Madhura

  • 0
    TI__Mastermind 23226 points

    Hi Madhura,

    I have seen these used to protect the inputs from overvoltage. There are already ESD diodes configured this way internal to the device, but they can only safely carry about 20mA. External diodes can carry more current, and Schottky diodes will turn on before the internal silicon diodes.

    An input resistor and a filter capacitor are also helpful to filter transient overvoltage, and also limit current through ESD diodes. Since the inverter is a noisy place, I recommend a filter for signal integrity, not just TVS.

    TI has a wide range of TVS diodes available. One example is ESDS302. The rating will depend on the expected source of overvoltage. 

    Also, please update from the UCC21520 to the newly launched UCC21550. It is a much improved device.

    Best regards,

    Sean