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Original question:

UCC27517A-Q1: UCC27517A-Q1

UCC27517A-Q1: ucc27517A-Q1

ADITYA ARYA
Prodigy 60 points
Part Number: UCC27517A-Q1
Other Parts Discussed in Thread: UCC27517A

Tool/software:

Dear Rubas, 

As you know we are using TI gate driver ucc27517A-Q1 ic with our PFC+LLC controller  to drive PFC mosfets . PFC out put is 390V - 2.99A.

In previous mail we discuss on some issue regarding UCC27517A failure , and after discussing with you we take action on that like improvising the components.

but now we are facing same problem again  , when we conduct reverse diode test on failure gate drive ucc27517A-Q1 ic then we  found out pin failed rest pin is ok.

as you suggest in pervious mail on failure ic conduct test VDD pin to OUT pin and OUT pin to VDD pin,  then we found 

in failure ic when we connect positive probe of multimeter (in diode mode) on VDD pin and negative probe connect to out pin then found 1.121 voltage whereas in the fine IC not showing any voltage. .

and in failure ic when we connect positive probe of multimeter (in diode mode) on out pin and negative probe connect to VDD pin  found .600voltage  whereas in the fine IC we see .546 voltage.

for reference i have attached the schematic with bom and some wave form at different- different  input VAC 

 <---- this waveform on trigger mode at 170vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

<----  this study state waveform at 170vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

<---- this waveform on trigger mode at 230vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

<---- this study state waveform  at 230vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

<---- this waveform on trigger mode at 260vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

 <---this study state waveform  at 260vac output 54v load 15A , Ch1-out pin current , Ch2-vdd pin , Ch3- PFC mosfet gate (external mos.), Ch4-  in+ pin

LLC schematic.pdf0336.PFC schematic.pdfWSJM65R099DX(PFC and LLC mosfet).pdf

Thank

Aditya arya

  • 0
    TI__Expert 8660 points

    Hi Aditya,

    Can you reclarify the issue you are seeing? How is the IC failing? Is the OUT signal always high or always low or is it glitching? Is there any shorts between pins? How many devices are failing and under what conditions are they failing?

    I see in your schematic that the VDD bypass cap (C106) is 225pF. This value is very small, and it's recommended to use a value between 0.1uF to 10uF, and have it placed as close as possible to the gate driver. I would also recommend adding an RC filter on the IN pin:

    Thanks,
    Rubas

  • 0 in reply to Rubas Khalid
    Prodigy 60 points

    1. 20% failure coming from field - only gate driver ic failing , we are unable to identify condition when it is failing. Its an EV charger customer is using to charge vehicle  and returning after use of 1 week or 2. 


    2. failed IC - UCC 27517A -Q1 analysis - a) out pin is showing short to ground. b) in failure ic when we connect positive probe of multimeter (in diode mode) on VDD pin and negative probe connect to out pin then found 1.121 voltage whereas in the OK fresh IC not showing any voltage. .c) in failure ic when we connect positive probe of multimeter (in diode mode) on out pin and negative probe connect to VDD pin  found 0.600voltage  whereas in the fine IC we see 0.546 voltage.

    3. C106 is 225pf mans 2.2x10^6 pf = 2.2uF , and its very close to IC Vcc pin and ground you can check pictures in last reply. adding here again with mark on C106. 

    4. RC filter not added on IN+ pin - you can check the ok working board waveforms in last reply - Ch-4. IN+ pin waveform is clean. suggest why to add RC filter?


    We are looking support to conclude on issue , please suggest if call is possible as after multiple efforts some gap in understanding is there.

    Regards 

  • 0 in reply to ADITYA ARYA
    TI__Expert 8660 points

    Hi Aditya,

    Since this moved to email, I am closing this thread.

    Thanks,
    Rubas