Energy harvesting is an important pillar for large scale exploitation of IoT smart nodes and wearable devices. To this end, DC-DC converters with ultra-low start-up voltage, full integration and high efficiency in a wide input voltage range are required. In this paper a novel one-input, two-output DC-DC converter circuit is introduced. Low-power output provides 0.8-3.5 V with maximum load current of 3.5 mu A starting up from 98 mV input. High-power output is turned on by an ultra-low-power voltage detector when input voltage reaches 150 mV, to provide 0.8-2.4 V with maximum load current of 200 mu A. The circuit has been implemented in UMC 180-nm CMOS technology. Maximum simulated system efficiency is 34% at 0.2 V input. Low-power output meets the real time power demand of sensing, data processing and data storage blocks of IoT/Wearable devices, while high-power output provides sufficient power for data transmission, enabling batteryless operation.