This chapter provides an overview of the IoT sensor edge module, thermoelectric generator (TEG) and power converter. The target specifications of wearable electronic devices with TEGs are defined. TEGs are used in a wide variety of applications in terms of operating temperature and power level, ranging from high-power generation (over 1 kW at –160 and 800 °C) to low-power generation (on the order of μW at room temperature). This book focuses on TEGs for wearable electronics. One has three options for power converters for low-power applications: self-oscillation transformers, switching regulators and charge pumps. Wearable devices need to be provided with a small form factor. Small numbers of bulky external components are needed. Thus, charge pumps with no external components are selected as fully integrated power management circuits.