This document summarizes a paper about modeling a buck converter in Simulink without using Sim Power Systems elements. It begins with an introduction and defines a buck converter as a DC-to-DC power converter that steps down voltage while stepping up current. The document then presents the basic operation of a buck converter using two switches, typically a transistor and diode, to control current in an inductor. It also discusses efficiency factors such as conduction and switching losses. Applications mentioned include switched-mode power supplies, DC motor control, and battery chargers. In conclusion, the document states that a mathematical model is derived to accurately represent the buck converter in Simulink and allow tuning of controllers.