TPS40057: Is the TPS40057 suitable for load-share designs?

Chester N.

Part Number: TPS40057
Other Parts Discussed in Thread: UCC29002, , TPS40054, TPS40055, TPS40050, TPS40051, LM5143, LM25145

Hi Texas Instruments,

I would like to use the TPS40057 controller for my current project. This project must have a load sharing feature using this controller. I'm planning to use the UCC29002 to control the load sharing using the similar circuit given on figure 2 of SLUA311 application note. However, there is a statement in the application note that says "Load sharing multiple modules requires each individual module to start up into a pre-biased load and not sink current supplied by other modules supporting the output".

Based on the datasheet of TPS40057, it can source and sink with Vo prebias. Does that mean the TPS40057 is not suitable for load sharing application? The following descriptions are quite unclear for me, can you please help explain the following details?

• TPS40054 Source Only
• TPS40055 Source and Sink
• TPS40057 Source and Sink With VO Prebias

Thanks and regards,
Chester

over 3 years ago

0 Marshall_Beck over 3 years ago

TI__Mastermind 28530 points

Hello Chester,

I interpret the statement as TPS40051 is suitable for load sharing application, TPS40050 is not.

I will need to confirm, but I do not see anything in the datasheet that tells me TPS40057 is unsuitable for load sharing.

0 Marshall_Beck over 3 years ago in reply to Marshall_Beck

TI__Mastermind 28530 points

I also was given the suggestion of recommending a few newer-generation devices that may be better suited for load sharing application, in implementation and in improved device performance.

Please see suggested device and their corresponding quickstart calc tool. LM5143 quickstart tool has embedded multiphase solution calculations which will be useful for you in your application.

LM25145

https://www.ti.com/tool/LM25145DESIGN-CALC

LM5143

https://www.ti.com/tool/LM5143DESIGN-CALC

0 Marshall_Beck over 3 years ago in reply to Marshall_Beck

TI__Mastermind 28530 points

Hello Chester,

Saw you didn't think I resolved your question.

Do you have concerns with device recommendation?

0 Chester N. over 3 years ago in reply to Marshall_Beck

Prodigy 120 points

Hi Marshall Beck,

Thanks for the device recommendations but for some reason, I would like to stick with TPS40057. Please help provide the meaning of the following descriptions from the datasheet:

• TPS40054 Source Only
• TPS40055 Source and Sink
• TPS40057 Source and Sink With VO Prebias

I cant find the meaning of these descriptions within the datasheet.

Thanks,

Chester

0 Marshall_Beck over 3 years ago in reply to Chester N.

TI__Mastermind 28530 points

Hello Chester,

I would like to provide further explanation.

Is there confusion to what prebias means?

Please specify the concerns and I will work towards getting you the answers.

0 Chester N. over 3 years ago in reply to Marshall_Beck

Prodigy 120 points

Hi Marshall Beck,

Referring to the following datasheet attributes of each controller from the series:

• TPS40054 Source Only
• TPS40055 Source and Sink
• TPS40057 Source and Sink With VO Prebias

Please provide explanation about what source only and source and sink mean.

Regards,

Chester

0 Marshall_Beck over 3 years ago in reply to Chester N.

TI__Mastermind 28530 points

Hello Chester, sorry for the delay.

Source would mean the average or DC current of one of the buck phases would be > 0A.

Sink would mean the average or DC current of one of the buck phases would be < 0A.

Ensuring current is shared equally due to system concerns, or to ensure that device is not sinking current, as it is ill-advised, can be achieved by referencing an appnote such as this in aiding in the multi-phase design : https://e2e.ti.com/blogs_/b/powerhouse/archive/2017/11/03/how-to-design-a-simple-two-phase-current-sharing-synchronous-buck-regulator-using-a-voltage-mode-controller

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TPS40057: Is the TPS40057 suitable for load-share designs?