UCC29002: issues with setup?

Adam Daluga

Part Number: UCC29002

Hello,

One of my customers, is using the UCC29002 load share controller. They have an application that uses this chip powered off of a 12V bias to load share for a 15V output, with the sense line essentially right on the adjust pin. The datasheet specifies that this pin should not go above the Vdd but the block diagram shows the ADJ pin being open collector and from this simplified diagram they don’t see an issue. Could you give any detail on this and whether or not having this setup will cause issues or possibly be a reliability concern?

Thanks,

Adam

over 2 years ago

0 David Huang33 over 2 years ago

TI__Genius 9140 points

Hi Adam,

thanks for your interest in UCC29002.

The Vadj must never exceed, otherwise the output voltage can increase significantly when VADJ added to the close loop trace of the module. The other drawback it that during turning on and off condition, the output voltage also will increase significantly.

so for a UCC29002 application, please make sure Vadj<VDD.

TI recommend you use the calculation of the controller to do the Radj calculation . you can follow the below link for the calculator.

www.ti.com/.../UCC29002

0 Adam Daluga over 2 years ago in reply to David Huang33

TI__Expert 5680 points

Thank you David.

It sounds like our design could be improved then, but is there anything about this condition (Vdd =12V, Vadj = ~15V) that would be a concern in terms of reliability or overstressing the part?

0 David Huang33 over 2 years ago in reply to Adam Daluga

TI__Genius 9140 points

hi Adam,

Sorry we do not have a result at the condition you mentioned since it is already out of the recommended value for this controller.

again we suggest to follow the design tool to avoid the abnormal load share function.

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UCC29002: issues with setup?