A Nanocurrent Power Management IC for Low-Voltage Energy Harvesting Sources

This paper presents the nanopower design of an integrated 1 μW-to-5 mW power management circuit. The circuit integrates a boost converter with maximum power point tracking, a low drop-out voltage regulator (LDO), and a start-up circuit for battery-less activation from discharged states. The IC implements a dynamic two-way power routing policy that ensures a fast start-up from discharged states even with very large energy storage capacitors. In order to reduce the intrinsic power, asynchronous control logic was adopted. The circuit was implemented in a STMicroelectronics 0.32 μm microelectronic technology. The power conversion section and the LDO draw respectively stand-by currents of 121 nA and 414 nA in the active modes. The circuit achieves a peak conversion efficiency of 77.1% and a minimum start-up voltage of 223 mV.