# How to determine these resistors in 2-pole 2-zero feedback loop compensation

I'm trying to build a 2-pole 2-zero feedback loop compensation for controlling a full bridge dc-dc converter. It's my first time doing this and I'm following the book power supply cookbook. Book is not talking about these resistors or I'm mising something about them.

I'm using SG3525 and the error amplifier on it.

• Rr only affects Input bias offset so if it matters match it to R1, while R1 is only significant if >=10R3 otherwise if less than R3 reduces effects of C3 – Tony Stewart EE75 Jan 25 '20 at 16:21
• $R_1$ sets the output voltage together with $R_{lower}$ connecting the (-) pin to ground but it is missing in the schematic. Have a look at the seminar I taught at APEC in 2010 cbasso.pagesperso-orange.fr/Downloads/PPTs/… it describes many compensation structures, including the type 3 you have shown. – Verbal Kint Jan 25 '20 at 17:26