A discrete model of the DC charge-up phase in RFID rectifiers

This paper presents a discrete model of the DC charge-up phase in a single MOS diode rectifier for an inductively coupled RFID system. The model was derived for a rectifier driven by a coil antenna and with a storage capacitor connected to the output. A comparison between the model and a simulation of a rectifier implemented in a 0.35 μm CMOS process demonstrated fast and accurate modeling of the charge up-phase for both LF and HF RFID applications. The model was used to determine the relationship between the voltage induced in the coil antenna and the available chip current based on a specification for the durations of the charge-up and the data-communication phases in a typical LF RFID application.