UCC28740: Power cut-off phenomenon in a circuit

Conor

Part Number: UCC28740

Tool/software:

Hi,

We are currently investigating a power cut-off phenomenon in a circuit using UCC28740D. The timing of the malfunction is undefined after the system starts up, but it occurs about 1 to 8 hours later. The circuit uses UCC28740D and generates 5V from DC280V. It seems that the Primary overcurrent fault (CS-pin) is being misdetected due to noise. Increasing Cs from 100p to 200p did not improve operation. Do you have any comments? Please allow private messages if you need additional information.

Thanks,

Conor

over 1 year ago

+1 Manuel Alva Hernandez over 1 year ago

TI__Genius 15566 points

Hi Conor,

Please provide schematic and layout. Also, could you please provide the following waveforms when this problem happens?

-(VDD-GND)

-(DRV-GND)

-(VS-GND)

-(CS-GND)

Time scale ~10us, you can put the trigger on (VDD-GND) channel UVLO_ON (21V) or on (DRV-GND) channel for ~10V. With that information, we can find what fault is being triggered and then find the solution with the schematic and layout.

Thank you

0 Conor over 1 year ago in reply to Manuel Alva Hernandez

Guru 12235 points

I have contacted you by email, please reply. I will close this thread.

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UCC28740: Power cut-off phenomenon in a circuit