Battery-free circuit device for RF identifying tag
AssigneeHoltek Semiconductor Inc.
InventorsJeng-Rern Yang, Tsung-Han Yang
Life of this patent
Estimating the term…
Abstract
This invention relates to a battery-free circuit device for RF identifying tag. It is advantageous that the electric potential across the antenna coil induced by the change of the alternating magnetic field of the radio wave signals is independent of the modulational switching of the RF identifying tag during the positive half cycles when the antenna is receiving the radio wave signals from the card reader, and that the efficiency of the voltage-charging rectifier circuit remains constant when the data are delivered into the card reader. Furthermore, in this invention, the modulational amplitude of the signals is larger than that in the prior art, thus the propagating distance is longer and it shows better accuracy and reliability in data reading.
Claims15
A battery-free circuit device for RF identifying tag comprising:
- a signal process circuit having an output, the signal process circuit providing time sequence modified signals;
- a resonator that includes an antenna which resonates the signals received by the antenna,
- a voltage-charging rectifier circuit which is coupled to the resonator and is used to rectify the signals received by the antenna,
- a control computational circuit which is coupled to the voltage-charging rectifier circuit and the signal process circuit and is used to computationally control the modified wave form signals and is also used to control the operation of the battery-free circuit device for RF identifying tag,
- a frequency divider which is connected to the output of the signal process circuit and the control computational circuit and is used to divide the frequency of the time sequence modified signal, under the control of the control computational circuit,
- a shift register which is connected to the frequency divider and the control computational circuit and is used to load the signals that are then returned to the signal process circuit and finally emitted from the antenna;
- a capacitor that is coupled to ground;
- a voltage limiter that is connected in parallel with the capacitor;
- and
- wherein the voltage-charging rectifier circuit includes two diodes, with the p-terminal of a first diode coupled to the n-terminal of a second diode, with the p-terminal of the second diode coupled to ground, and with the n-terminal of the first diode coupled to the voltage limiter.
A battery-free circuit device for RF identifying tag, comprising:
- a signal process circuit having an output, the signal process circuit providing time sequence modified signals;
- a resonator that includes an antenna which resonates the signals received by the antenna,
- a voltage-charging rectifier circuit which is coupled to the resonator and is used to rectify the signals received by the antenna,
- a control computational circuit which is coupled to the voltage-charging rectifier circuit and the signal process circuit and is used to computationally control the modified wave form signals and is also used to control the operation of the battery-free circuit device for RF identifying tag,
- a frequency divider which is connected to the output of the signal process circuit and the control computational circuit and is used to divide the frequency of the time sequence modified signal, under the control of the control computational circuit,
- a shift register which is connected to the frequency divider and the control computational circuit and is used to register the signals that are then returned to the signal process circuit and finally emitted from the antenna, and
- an RF amplitude limiter having a first terminal that is coupled to the voltage-charging rectifier circuit, a second terminal that is coupled to the resonator, and an alternating amplitude limiter connected in parallel with a diode, and wherein the alternating amplitiude limiter uses a zener diode, and operates to limit alternating signals.
Dependencies are inferred from the claim text.