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UCC27201: UCC27201 HI and LI sink current

Red Yen
Expert 4310 points
Part Number: UCC27201

Hi Team 

my customer would to series pull down resistor on HI and LI pins for protection while abnormal happened  

pls advice what series resistor values can be used  and whit is max sink current for both HI and LI pins? 

  • 0
    TI__Genius 9790 points
    Thanks for your interest in TI here. I've contacted the appropriate product group. You should hear from them soon.
  • 0
    TI__Genius 13445 points
    Hi Red Yen,

    Thank you for reaching out to us. My name is Mamadou Diallo, I am an applications engineer here in MID group(MOSFETs and IGBTs Drivers) and I will work to help address your concern...

    The UCC27201 has a nominal impedance of 200-kΩ at its input, this pulldown resistance is referenced to VSS (ground). Generally, you want to avoid shaping input signals to the gate driver in an attempt to slow down the signal at the driver output. Depending on your application, you want to use Rhi and Rli in the ranges of 10 Ohms - 100 Ohms along with capacitors with Chi and Cli values in the ranges of 10 pF and 220 pF.

    Now Is there any specific as to why you're trying to sink current at the driver input?

    Regards,

    -Mamadou
  • 0
    TI__Mastermind 21675 points

    Hello Yen,

    My name is Richard Herring and I work with Mamadou in the High Power Driver group. I want to clarify your question to be sure to provide the correct answer.

    You mention the customer would like to series a pull down resistor on the LI and HI pins for protection during abnormal conditions. Does this mean the customer want to add a resistor from the controller in series with the driver input pins? Or does the customer want to add a resistor from the HI and LI input pins to VSS?

    If you can clarify where the customer wants to add the resistance, we can provide a quick response.

    Regards,

    Richard Herring

  • 0 in reply to Richard Herring
    TI__Expert 4310 points

    Hi Richard, 

    the first one, customer want to add a resistor from the controller in series with the driver input pins, and the pull down single direct connect with HI and LI while abnormal happened as my attached picture 

    thanks a lot 

  • 0 in reply to Red Yen
    TI__Mastermind 21675 points
    Hello Red,
    The general advice we give for the series resistance from the controller to the driver is 10 to 100 Ohms resistance. The fault that you indicate, an abnormal short at the driver input will result in current being supplied from the controller into the series resistance which is shorted at the driver. This is not a concern for the driver pull down capability, since the abnormal fault or short is external to the driver. The driver internal LI and HI pull down resistance is high at 200K Ohms nominal which will not have much affect on the voltage drop in the series resistance of 10 to 100 Ohms.
    You should confirm that the driver input pins shorted after the series resistance is not a concern with the controller drive current capability.
    Please confirm on this thread if this resolves your concerns.

    Regards,
    Richard Herring