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Most textbooks teach you how a buck, boost, or flyback converter works. They give you the ideal transfer functions. But real life is not ideal. Parasitic capacitance, leakage inductance, PCB trace resistance, and core losses destroy theoretical efficiency.
Note: While Sanjaya Maniktala is a definitive authority in this field, his most famous work is titled "Switching Power Supplies A to Z." The specific title "Switching Power Supply Design Optimization" often refers to the advanced techniques, efficiency chapters, and magnetics optimization strategies found within his primary text or subsequent application notes. This report synthesizes the core optimization methodologies presented in his body of work.
A power supply can have great efficiency but be unusable if it oscillates.
If you locate a legitimate copy of this PDF, here is what you will find (based on the standard edition):