I'm reading ADP2386 and I just wondered how this RC value's calculation fomula come from.
Would anyone advie me how to reach this fomula?
Please see the attached file.
Hello Tarzan, I might be a little off subject here, but have you checked out ADISimpower? there is a downloadable tool for the ADP2384 that will do the design for you. Here is a link to the list of design tools.
Thank you for your reply.
I've already checked ADIsimpwer, but It looks like it's not easy to adjust the cross over frequency on it.
I want to improve load transient respond without adding extra capacitors.
Anway, I will try to find out the way.
If you konw any good material to explain compensation network circuit, please let me know.
Thanks in advance.
the equation in the datasheet is a simplified derivation of the control loop gain, so as you see you can increase Rc to increase the bandwidth (gain).
ADIsimPower compensates the design for a Fsw/10 if possible or to guarantee a >45deg (60 typ.) phase margin. So potentially you have some margin to increase the crossover frequency (gain) slightly but you need to consider the fact that if you do that your phase margin may decrease and with component tollerances you may not have optimal transient response over temperature of from lot to lot.
The easiest and more effective way to increase bandwidth and transient response speed without the need for more caps is to increase the switching frequency. This can also be done in ADIsimPower advanced settings by manually selecting the switching frequency.
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