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UCC28180: MOSFET Damage

Kalp Bhatt
Prodigy 20 points
Part Number: UCC28180

Tool/software:

Hi TI Community,

We are using UCC28180DR to control and drive a boost PFC with 400V dc output voltage and 1 kW rating. IC peripherals are highlighted in the image shared below.

We are facing hardware damage issue where in the shunt current sense resistors and MOSFET gets damaged. As per the datasheet, IC provides soft overcurrent feature and peak overcurrent limit (PCL). Using design guide provided by TI, the calculated value for PCL is 29.2 Amps. At the same time selected MOSFET, IPP60R120P7 has a pulsed current rating of 78A. 

Regarding this,

Is there any delay in PCL or SOC implementation logic?

Shouldn't PCL protection turn OFF the gate pulses to MOSFET?

Your insights are welcomed and it will be helpful if you can suggest a solution for the same.

Thank you for your help

  • 0
    TI__Genius 9490 points

    Hello Kalp,

    Can you please share the UCC28180 design calculator with the values that you inputted? Also, do you have any oscilloscopes screenshots of waveforms such as the switch node?

    Regards,

    Jonathan Wong

  • 0 in reply to Jonathan Wong
    Prodigy 20 points

    Hi Jonathan,

    I am sharing the design sheet with you.

    Unfortunately, these damages are intermittent, hence, we do not have any visual data depicting the fault conditions at switch node for your aid.sluc506c.xlsm

  • 0 in reply to Kalp Bhatt
    TI__Genius 9490 points

    Hello Kalp,

    Does your UCC28180 work properly during normal operation? What conditions trigger this damage (Ex. damage occurs at a certain Vin). It will be helpful if we can find some waveforms to see if your controller is working properly or not.

    Based on your schematic, the Peak Current Limit (PCL) is set at 29.2A. This is because of the formula 55 on page 28 on the datasheet. The PCL does have a 300ns blanking time as shown in the block diagram but this blanking time should not be long enough to cause significant damage to MOSFETs. 

    Can you try using a signal generator to generate a PCL signal and test to see if the UCC28180's PCL feature is working properly? Input a -0.4V signal onto the UCC28180 ISENSE pin manually and see if the PWM output shuts off. Take waveform screenshots to analyze the behavior. 

    Are you able to operate your UCC28180 at light load (Ex. <500W)? What are the waveforms at light load?

    Regards,

    Jonathan Wong