TPS54560: the IBB's loop compensation

wenhe hou

Prodigy 55 points

Part Number: TPS54560

Tool/software:

If I use a buck to generate negative pressure, what should I pay attention to for loop compensation?

thx

5 months ago

0 Onkar Bhakare 5 months ago

TI__Genius 14236 points

Hi Wenhe

Thanks for showing interest in our products!

The inverting buck boost topology has interesting difference when compared to buck. IBB has right half plane zero in its small signal closed loop transfer function. It introduces negative phase causing more phase delay. Additionally, it increases, which can lead to instability if not managed properly.

Following equation gives location of RHP zero.

Keep RHP pole at least 4 times of loop crossover frequency

Let me know if you have further doubts in this

Thank you

Regards

Onkar Bhakare

0 Onkar Bhakare 5 months ago in reply to Onkar Bhakare

TI__Genius 14236 points

Hi Wenhe

Let me know if you have further questions

Thank you

Regards

Onkar Bhakare

0 wenhe hou 5 months ago in reply to Onkar Bhakare

Prodigy 55 points

HI，Onkar

Thank you very much for your reply. I would like to know if there are detailed examples of using a buck converter to generate negative voltage. Is the zero and pole of the ic itself also considered? And what is the difference between the two?

THX

0 Onkar Bhakare 5 months ago in reply to wenhe hou

TI__Genius 14236 points

Hi Wenhe

You can check following application note for design example - Create an Inverting Power Supply from a Step-Down Regulator (Rev. B).

Let me know if face any difficulties in the design process

Thank you

Regards

Onkar Bhakare

Power management

Power management forum

TPS54560: the IBB's loop compensation