RFID TRANSPONDER WITH PLL
First Claim
1. An RFID transponder, comprising:
- an antenna for receiving data in a downlink mode and transmitting data in an uplink mode;
a modulation stage for modulating uplink data and a demodulation stage for demodulating downlink data; and
a class C amplifier comprising a resonant circuit (L, C), a plucking device (T1) coupled to the resonant circuit, and a controllable pulse width generator (PWM) coupled to the plucking device (T1), the controllable pulse width generator (PWM) being adapted to periodically switch the plucking device (T1) on and off so as to maintain an oscillation of the resonant circuit (L, C), wherein the transponder further comprises a phase locked loop (PLL) configured to be locked to an oscillating signal received through the antenna and to be switched into a free running mode without being locked to the oscillating signal received through the antenna, thereby being adapted to output an internal clock signal for the RFID transponder, which is independent from the oscillating signal received through the antenna.
2 Assignments
0 Petitions
Accused Products
Abstract
An RFID transponder comprises an antenna for receiving data in a downlink mode and transmitting data in an uplink mode, with a modulation stage for modulating uplink data and a demodulation stage for demodulating downlink data. A class C amplifier is provided, which has a resonant circuit, a plucking device coupled to the resonant circuit, and a controllable pulse width generator coupled to the plucking device. The controllable pulse width generator is adapted to periodically switch the plucking device on and off so as to maintain an oscillation of the resonant circuit. The transponder further comprises a phase locked loop configured to be locked to an oscillating signal received through the antenna and to be switched into a free running mode without being locked to the oscillating signal received through the antenna, thereby being adapted to output an independent internal clock signal for the RFID transponder.
63 Citations
10 Claims
-
1. An RFID transponder, comprising:
-
an antenna for receiving data in a downlink mode and transmitting data in an uplink mode; a modulation stage for modulating uplink data and a demodulation stage for demodulating downlink data; and a class C amplifier comprising a resonant circuit (L, C), a plucking device (T1) coupled to the resonant circuit, and a controllable pulse width generator (PWM) coupled to the plucking device (T1), the controllable pulse width generator (PWM) being adapted to periodically switch the plucking device (T1) on and off so as to maintain an oscillation of the resonant circuit (L, C), wherein the transponder further comprises a phase locked loop (PLL) configured to be locked to an oscillating signal received through the antenna and to be switched into a free running mode without being locked to the oscillating signal received through the antenna, thereby being adapted to output an internal clock signal for the RFID transponder, which is independent from the oscillating signal received through the antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A method for operating a RFID transponder, which is adapted to receive data in a downlink mode and to transmit data in an uplink mode, the method comprising:
-
locking a phase locked loop (PLL) to an oscillating signal received through an antenna; and switching the phase locked loop (PLL) into a free running mode without being locked to the oscillating signal received through the antenna thereby providing an internal clock signal for the RFID transponder at an output of the phase locked loop (PLL), which is independent from the oscillating signal received through the antenna.
-
-
10. In an RFID transponder, having an antenna for receiving data in a downlink mode and transmitting data in an uplink mode and a modulation stage for modulating uplink data and a demodulation stage for demodulating downlink data;
- an oscillator comprising;
a class C amplifier comprising a resonant circuit (L, C), a plucking device (T1) coupled to the resonant circuit, and a controllable pulse width generator (PWM) coupled to the plucking device (T1), the controllable pulse width generator (PWM) being adapted to periodically switch the plucking device (T1) on and off so as to maintain an oscillation of the resonant circuit (L, C).
- an oscillator comprising;
Specification