patents.google.com
5/1/2006
TWI254252B - Power processing interface of passive radio frequency identification system - Google Patents
The present invention relates to a power processing interface of a passive frequency identification system, comprising the followings: a resonant circuit that detects a first modulated signal transmitted from a transmitting end and uses the first modulated signal as an AC voltage source; a first rectification circuit that is electrically connected to the resonant circuit for converting the AC voltage into a DC voltage; a filter circuit that is electrically connected to the first rectification circuit for generating a stable working voltage in response to the DC voltage; a voltage detection circuit that is electrically connected to the filter circuit and the first rectification circuit for detecting the voltage level of the working voltage; a second rectification circuit that is electrically connected to a voltage clamping and modulating circuit and the resonant circuit; and the voltage clamping and modulating circuit that is electrically connected to the first rectification circuit and the second rectification circuit for using an output of the voltage detection circuit to control conduction status of the second rectification circuit on the basis of the voltage level of the working voltage so as to bypass excessive current and to provide an effective minimum voltage level for the radio frequency identification system in the process of modulation and transmission for maintaining normal operation of the radio frequency identification system.