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UCC28951: Adding Extra delay on gate driver to avoid shoot through at system Level.

Part Number: UCC28951
Other Parts Discussed in Thread: UCC21550

Tool/software:

Hello Mike.

I'm using UCC21550x driver to drive H-bridge FETs. My system has different loads connected to DC BUS. What i'm observing is, sometimes the Signals coming out of UCC28951 Controller, is being altered due to some noise present in the system. To protect my FETs from shoot-through, I'm planning to introduce and additional delay using DT pin of gate driver ( UCC21550). 

let us say, for instance i add 20k on DT PIn ( around 200nS ), My fixed delays from UCC28951 are 240nS.

The DT pin of gate driver,  This feature is used to prevent shoot-through, and it does not affect the programmed dead time setting for normal operation.

My question is , in case of event ( where both signals overlap due to some system noise ) , and DT pin function is activated, Will it disturb my Loop response ( duty cycle adjustment ) and its Ok to include Dead time of gate driver ??

  • Khan,

    if you are using the DT feature of the iso driver, then the min DT is dictated by the driver, not by UCC28951 anymore. When you have the noise interfering UCC28951 output, then the loop response isn't really apply, IMO. I'd suggest to address the noise source instead.

    Best,

    Ning