This slide book introduces the demands of emerging power-supply integrated circuits (ICs) and discusses up-to-date circuit-design techniques aimed at addressing them, especially within the context of portable microelectronics. The presentation reflects the "top-down design" systems-to-circuits approach that industry adopts when developing power-supply systems. Within this framework, concepts evolve organically "from the ground up" with an educational mindset, rigorously surveying, analyzing, and evaluating basic theory and the state of the art. In this way, the material presents, explains, and shows how to understand, develop, and use semiconductor devices to model, analyze, and design ICs that supply and sustain microelectronic loads. The ultimate objective is to cultivate and develop insight and intuition. Some of the topics covered include power consumption, frequency response, feedback control, and power supply rejection.