what is 'transient response'?

[wowo1215]

Hi All,
I am a newbie on buck converter. By now, I know the transient response is the performence related to dynamic load, but what is this phase exactly mean? And how to improve it? Thanks.

 

[FvM]

Transient response means the response (temporary output voltage change) of the converter due to load transients (e.g. a current step).
Typically, you'll observe a short voltage drop as response to a positive current step, but there may be also a ringing.

The term seemed obvious to me from datasheet information up to now.

 

[wowo1215]

Thanks,FvM.
So any suggestion to improve it? It seems to be related with phase/gain of the control loop,but I really have no idea on what's the relationship between them.

 

[gilbertomaldito]

If you want to Measure the Phase and Gain, definitely you must input 1mV to the Op Amp which serves as a feedback of your buck converter and measure the dB(Vout) at the output of your buck. This is AC analysis.

Transient Analysis will let you see your output voltage time response. If you designed a 3V output, more or less your output will be 3v with ripples.

There are 3 ways to incorporate compensation to get a better stability. they are named to be type I , type II and type III. Only type II and type III can do the compensation for Buck converters.