Hello
I have 18V(0.8Amp)/-18V(0.6Amp) rail with common ground (please see attached picture) and I need to buck+18 to +8 and -18V to -8V. Since I have a common ground that means I need a negative buck dc-dc converter. I studied other replies provided in this site for similar question and figured out that I need to use Lm5001 or Lm3102 or similar IC’s with boost topology to implement negative buck . I’m familiar with TPS54140 buck switcher and I want to use it for +18V to +8V rail with no issue. I can use Lm5001 for bucking -18V to -8V. I saw some circuit suggesting by TI online . I know that I need to add Bjt mirror configuration for feedback. However, I do not know how to calculate the component values for mirror and feedback compensation network. I usually use webbench to design dc/dc converter component values, But I do not know how to use Webbench to calculate the components value for LM5001 configured as negative buck. Can you please help me with that?