Step-Up Switched-Capacitor (SC) AC-DC Converters for RFID Tags

In signal processing circuits of a RDIF tag, the relaxation of restriction concerning operating voltage range enables us to develop various applications. In order to provide higher voltage to the signal processing circuit, two types of step-up AC-DC converters for RFID tags are proposed in this paper: the step-up converter and the step-up converter. To reduce ripple noise of output voltage, the proposed converters consist of 2 charge-pump type AC-DC converters with opposite polarities. Unlike conventional converters, the proposed converters can offer higher output voltages by realizing / step-up conversion. Furthermore, as for the step-up converter, the circuit size of the proposed converter is almost the same as that of the Cockcroft-Walton type AC-DC converter. The properties of the proposed converters are clarified by theoretical analyses. The theoretical formulas can derive the equivalent circuits, output voltages, and power efficiency. Furthermore, SPICE simulations and the experiments showed the validity of theoretical formulas and circuit design.