An Ambient Energy Harvesting Interface for Battery-Free Wireless Sensor Nodes

This paper presents a low-quiescent-power battery-free energy harvesting interface for micro-watt to milli-watt applications with a single-inductor dual-input dual-output (SIDIDO) buck-boost converter. The system contains one renewable source input, one regulated output and one bidirectional energy transfer node with a storage capacitor for storage and reuse the energy. To achieve high power conversion efficiency (PCE) with micro-watt input power, we embedded dynamic-power-gating under-voltage lockout (DPG-UVLO) circuit, dynamic-voltage-feedback (DVFB) and pulse-frequency modulation (PFM) control to reduce quiescent power. The measurement quiescent power is 1.9 µW and the peak PCE is 86.4%.