This seminar presents a detailed step-by-step analytical method of closing switch-mode power converter feedback regulation loops. The hand derivation and solution of the pertinent converter equations is typically error-riddled and difficult for higher order converters (e.g., SEPIC), or if parasitics are added. Therefore, the method presented here circumvents this problem by using a spreadsheet program such as Mathcad or Excel to do the for the calculations. In particular, the state equations of the averaged and linearized power stage are formulated in matrix form, to allow for the system transfer functions to be evaluated using Cramer’s Rule, thereby greatly reducing errors. A universal system block diagram that automatically caters for both voltage and current mode control is used as a framework for investigating the closed-loop system behavior. All the calculations are done by the spreadsheet program. The target audience is intermediate to advanced power supply designers.
