LMR36520: voltage compensator output limitation in peak current mode

Zach Xia

Part Number: LMR36520

Hi team, I am learning peak current mode. I suggest that the limitation of voltage compensator output would influence the load transient behavior.

And in the datasheet, load transient waveforms are very smooth without reverse over/undershoot.

I guess the min limit of voltage compensator output is around zero, and there would not be large negative values. Because if there is big negative accumulation on the output, it will take a long time to recover, making a second shoot. And the max limit may be decided by the max peak current.

Or the loop is compensated so well, and second shoot should not happen?

Hope you'll help to clarify this.

Regards,

Zach

over 4 years ago

0 Daniel Li14 over 4 years ago

TI__Mastermind 27470 points

HI Zach:

when the loop well compensated, it have enough phase margin(>35deg C) and gain margin , threre will be no reverse over/undershoot

Thanks

0 Zach Xia over 4 years ago in reply to Daniel Li14

TI__Expert 8215 points

Hi Daniel,

Thanks for your reply! The loop is compensated well, such that the load disturbance could be well responded.

What if the reference has a step change, in my simulation when Vref steps down, a reverse shoot happens. But when Vref steps up, there is no obvious reverse shoot. Does this difference come from the upper limit of eaout and inductor current max limit(they have the same control loop as load transient)?

eaout: voltage compensator output