摘要
This paper presents an interface design for electromagnetic energy harvesting for wearable applications. A transducer design is proposed. Multiple segments of coils with alternating winding directions improve the induced voltage and power. Due to the source&null wideband nature in target applications, we avoid the use of springs common in conventional designs. The corresponding equivalent circuit model is presented. A system-level analysis is then performed that leads to the following power interface circuit design. It includes a differential rectifier and a switched-inductor boost converter. The harvested power is maximized with a constant-resistance load that can be adjusted through a variable-gain amplifier&null gain. Implemented in a 0.18-&null CMOS process and tested at 20 Hz, measurement results show &null impedance matching efficiency with &null input voltages. The system is able to harvest 320 &null when shaken by hand at 2.5 3 Hz.