In Part I, the design of an ASIC control chip for a forward active clamp converter is presented. Integration of the control and drive circuit into one IC chip results in higher power density, higher reliability for the converter module. The designed ASIC control chip uses a 2.0 um N well Analog CMOS process, and is fabricated at MOSIS. The design procedures of the ASIC chip are explained, and experimental results are presented. Part II of the thesis focuses on the numerical investigation of several integratable lateral power devices. Lateral power devices are used in power IC designs because of their compatibility with analog & digital IC process. To obtain devices with high current density, large safe operating area, fast response and low cost is highly desirable for power ICs. In Part II of this thesis, several lateral power devices are discussed and simulated, including lateral IGBT, lateral MCT and double gate lateral MCTs. It is shown that lateral IGBT and lateral MCTs are good candidates for power IC applications. / Master of Science