Supply voltage scaling has become an important low power technique to reduce the power consumption of sub-nanometer technologies. Instead of supplying same magnitude of Vdd for the whole chip, multi-Vdd and Dynamic Voltage Scaling (DVS) have been advocated for the enhanced power efficiency at the cost of added complexity. In this paper, we present a low area, low power on-chip DC-DC converter suitable for low power Wireless Sensor Network (WSN) nodes. This converter offers the flexibility to perform micro-level DVS for various blocks of the system. Peak efficiency of 90% has been achieved and the proposed DC-DC converter takes utmost delay of 30μs to switch between the different output voltages.