UCC28517: Audible Noise at Light Loads

Edward Paul

Part Number: UCC28517

Dear TI Support,

TI's Application Report SLUA309C to support the UCC28517 discussed the use of a bias resistor to counter the input offset voltage of the current error amplifier at light loads. The solution offered in the application report gives me a bias resistor value of 6.2MegaOhm!

Is this still an issue with the device at light loads and do I still need to fit this Rbias resistor?

Regards,

Edward

over 5 years ago

0 Hong Huang over 5 years ago

TI__Guru 51835 points

This resistor RBIAS is help to recude audible noise at light loads, so this resistor is needed. If in your case, the audible noise is small and tolerable in your application, then you do not have to use this resistor. Not exactly understand your question or concern - can you clarify?

0 Edward Paul over 5 years ago in reply to Hong Huang

Prodigy 50 points

Hi Hong, I noticed this application report in the techincal documents section for the UCC28517 online. It is dated April 2011 so I was just wondering if there had been a revision to the UCC28517 since then which meant that this resistor is no longer needed.

0 Edward Paul over 5 years ago in reply to Edward Paul

Prodigy 50 points

To add to this - I am not experiencing any noise at light loads so I do not need it.

0 Hong Huang over 5 years ago in reply to Edward Paul

TI__Guru 51835 points

We do not have a new combo or a new revision of UCC28517.

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UCC28517: Audible Noise at Light Loads