TPS565208: 12V to 5V regulator (using TPS565208) does not work

NILANJAN MUKHERJEE

Part Number: TPS565208

Hello

I have been trying to design a 12V to 5V 5A switching regulator and I have used TI's TPS565208 to perform this. I have followed the designed guideline on the datasheet. I do get 5V output when there is 12V at the input but output goes to zero when I connect any load across the 5V output. I measured pin 2 (SW) there is no switching happening. The load I'm connecting is 1K across the 5V (I have also tried putting 10R). I measured the inductor current and again no switching ripple. I doubt it is switching at all and outputting something arbitrary. Enable pin EN has been pulled to high.

This ideally should be pretty straight forward design - don't understand why the IC does not start up. Can you help?

regards

Nilanjan

over 6 years ago

0 Sam(MPAA) Zhang over 6 years ago

TI__Mastermind 19080 points

Hi Nilanjan,

Could you post your schematic here?

Also, I would recommend you to check if there is any soldering issue.

Thanks!

Regards,

Hao

0 NILANJAN MUKHERJEE over 6 years ago in reply to Sam(MPAA) Zhang

Prodigy 20 points

The schematics is attached - I checked soldering and build a new board but it simply does not work. I can see nice waveform posted in TI datasheet but the IC does not behave as it is promised.

0 Anthony Lang over 6 years ago in reply to NILANJAN MUKHERJEE

TI__Expert 4875 points

Hi Nilanjan,

Could you do us a favor to show the SW node waveform on the failure unit when you power up? Have you tried with any other samples on your board and have you seen the same phenomenon? Is there any other output caps beside the 47+10uf showed in the schematic? Need to double check whether you got into overcurrent condition. Thanks!

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TPS565208: 12V to 5V regulator (using TPS565208) does not work