A new resonance-shift voltage limiting mechanism for RFID transponder front-end circuit

Proposed is a new voltage limiting method for the front-end circuit of RFID tags. The technique is based on a resonance-shift mechanism which, when the induced voltage is too strong, will automatically alter the resonant frequency of the front-end to reduce the gain over the signal band and thus the induced voltage. In contrast to the conventional voltage-clamp circuits, this method is simple and efficient in terms of silicon area while not sacrificing the quality of the data transmission between the transponder and the reader. The proposed resonance-shift voltage limiting mechanism is applied in the design of a 13.56 MHz RFID transponder front-end circuit in 0.35 um double poly CMOS technology. The experimental results reveal the feasibility of this method.