Efficient and durable power supply is the backbone of any IoT Product. For a wearable or self-powered wireless device, power consumption and battery life are a big concern. In the coming years, with billions of “things” about to be connected to the Internet, power conservation is going to be a critical factor in deciding the economic feasibility of any IoT deployment. Apart from battery-powered devices, this is equally applicable for IoT gateways which run on 24/7 mains supply. In this post, we will discuss the essential design features needed to meet the requirements of an efficient power supply. Based on my experience of developing a power supply unit for a portable BLE IoT endpoint, I have also presented a prototype reference design of a battery charging circuit for standalone IoT devices.