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UCC28880: UCC28880 output unormal

Raymond He
Expert 1990 points
Part Number: UCC28880

1. There are 20 new LED lamps related to UCC28880 damage. Through cross-testing, it is found that the input and output voltages of the power supply under the input voltage of 90-100V are lower than those of the normal power supply.  Measurement of power supply temperature Defective product temperature is higher than the normal power supply  

 

2. After testing the voltage state of pins and cross-testing, the problem phenomena follow the chip, and submit the FA analysis  

ER046-S243WT (1.0.5)-2019.03.pdf

atachment is about sch，any advise？thanks in advance

  • 0
    TI__Guru 66135 points

    Hello,

    Please note that if you have defective devices you should work with the Texas Instruments Quality and Failure Analysis teams.

    Regards,

  • 0 in reply to Mike O'
    TI__Intellectual 1200 points

    Raymond,

    Did you do any measurements on the IC itself such as resistance between pins, etc? Did you capture any waveforms demonstrating the abnormal behavior of the IC? You also mentioned that the devices were submitted for FA; do you have any results to share? 

    I would recommend submitting a request through our Customer Return portal (link below) for further investigation. Note the more information you can provide regarding the abnormal behavior and the condition of the ICs (waverforms, schematics, traceability information, etc) the better equipped the team will be to help diagnose this issue. 

    https://www.ti.com/support-quality/additional-information/customer-returns.html

  • 0 in reply to Mike O'
    TI__Guru 66135 points

    Hello,

    I reviewed the schematic and could not see any major issues.  I do believe diode  D5 is not required by the design.

    The other thing you might want to check is that diode D3 and D4 are fast recovery diodes.  The following link will bring you to an application note that describes how to select these rectifier diodes.  https://www.ti.com/lit/an/slua855/slua855.pdf

    You might want to study the UCC28880 internal FET current as well to make sure it is not exceeding it's maximum limits.  The highest currents would be seen during power up, max load and during large signal transients.  If the absoulse maximum current is exceeded it could damage the UCC28880.

    Regards,

    Mike