UCC28631: The VDD voltage has been changing triangularly between two voltages.

user5346271

Prodigy 80 points

Part Number: UCC28631

I have many ucc28631.Their waveforms have different peaks and troughs.They are:

15V and 5V

10.6V and 5V:

12.6V and 5V:

I can't find the explanation from the datasheet.Can you tell me what the status of the chip is now?What's wrong with the ucc28631?

The schematic diagram is as follows

over 4 years ago

0 Hong Huang over 4 years ago

TI__Mastermind 47715 points

What are these waveforms? You need to label each waveform and describe where measured and operation conditions, also label each waveform with oscilloscope channel scale.

0 user5346271 over 4 years ago in reply to Hong Huang

Prodigy 80 points

Hello Hong Huang,
This is the waveform of the VDD pin (Pin 6) when the power is on.They show triangular waves varying between 5V and 15V or 10.6V and 5V or 12.6V and 5V.The detailed waveform is shown above.
thanks,

0 Hong Huang over 4 years ago in reply to user5346271

TI__Mastermind 47715 points

It looks VDD cannot stay above operation level. Check your bias winding and fault conditions to find what caused VDD ramp down.

0 Hong Huang over 4 years ago in reply to Hong Huang

TI__Mastermind 47715 points

I am closing this thread as no reply from you. If you need further support please open a new thread.

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UCC28631: The VDD voltage has been changing triangularly between two voltages.