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UCC5310: Detects unintended voltage and stops gate output

Conor
Guru 10970 points
Part Number: UCC5310
Other Parts Discussed in Thread: UCC5390

Hi,

I would like to know if TI's isolated gate driver can handle system abnormalities.

System configuration
・When normal operation: output side VCC withstand voltage is 40V and 20V is applied to VCC2.
・When normal operation: 15V is applied to the IGBT gate with negative bias of 5V.
・When an error occurs: 30V is applied to the output side VCC due to an error in the power supply circuit in the previous stage.
・When an error occurs: 25V is applied to the IGBT gate with a negative bias of 5V (gate breakdown voltage exceeds 20V)

Question
Is there a lineup of isolated gate drivers that can take measures against overvoltage to the IGBT gate during abnormal conditions? The following functions are expected.
■Detects unintended voltage on the insulated gate driver side and stops gate output
■The output of the insulated gate driver contains a constant voltage circuit and only outputs 15V. etc.

Thanks,

Conor

  • 0
    TI__Mastermind 20106 points

    Hi Conor,

    The abs max supply of this gate driver is 33V. From my testing, I can tell you that Vcc2 can withstand up to 46.5V at DC steady state. However, if you try and switch at this supply voltage, it will instantly damage the output side. Also, if you have a >70MHz transient current injection into the gate (and into one supply) when the supply is this high above the abs max, it will damage the predriver for the output stage. Of this gate driver family, UCC5390 is the most impervious to damage. 

    In your case, I think we can say that the gate driver will survive in all 4 cases. However, the IGBT will likely be damaged by 25V on the gate. You can usually get away with a little Vds overvoltage due to avalanche breakdown, but Vgs overvoltage is like throwing a rock at a thin piece of glass (gate oxide).

    UCC5880 is a device that monitors the output gate voltage and can stop unintended gate output. It will add complexity but has the feature lineup that you are requesting. 

    The best way to guarantee that the gate voltage does not exceed 15V is to use a TLV431-based clamp circuit on the power supply, which will act as a steep Zener clamp. If the power supply is clamped, transient voltages on the gate are unlikely if the circuit is well laid out (short gate charging loop length).   

    Best regards,

    Sean