Power electronics is at the heart of modern technology, enabling the efficient conversion and control of electrical energy in a wide range of applications. Within this domain, isolated power converters play a pivotal role, offering a safe and efficient means of transferring electrical energy across isolation barriers. This chapter introduces the fundamental concepts of isolated power converters, emphasizing their importance in ensuring the safety and functionality of electronic systems and discusses the challenges faced when trying to miniaturize the whole converter to fit in a single semiconductor package.