For low-voltage vibration energy harvesting, such as 0.5V@50Hz input, this paper presents a novel inductor-less step-up ac/dc converter. In the proposed ac/dc converter, high voltage gain can be achieved by combing a cross-coupled charge pump with a bipolar Cockcroft-Walton multiplier, where a rectifier-less design is realized by the bipolar Cockcroft-Walton multiplier. Furthermore, small EMI (Electro-Magnetic Interference) is provided by the inductor-less design. The performance of the proposed ac/dc converter with 12× step-up gain is evalutaed by theoretical analysis and SPICE (Simulation Program with Integrated Circuit Emphasis) simulations. The SPICE simulations demonstrated that the power efficiency of the proposed converter is about 88%@1mW with 1% ripple factor. Furthermore, breadboard experiments verify the feasibility of the proposed inductor-less topology.
