In accordance with a first aspect of the present disclosure, a radio frequency identification (RFID) transponder is provided, comprising: at least one functional component configured to perform a function of the RFID transponder; a charge pump configured to supply an output voltage to said functional component, wherein said charge pump comprises a plurality of charge pump stages; a charge pump controller configured to control a number of charge pump stages which contribute to the output voltage. In accordance with a second aspect of the present disclosure, a corresponding method of operating an RFID transponder is conceived.

Various embodiments may include an identification device comprising: a data memory storing a piece of information containing an identification; a processor generating a signal indicating the piece of information; an optical-to-electrical energy converter supplying power for the processor and converting electromagnetic radiation from the surroundings into an electric current feeding the processor via a power connection; an output device with a data connection to the processor for transmitting the signal; and an executable program stored in the processor for reading an input signal transmitted via the power connection and superimposed on the electrical current.

A dual frequency HF-UHF RFID integrated circuit including a power supply. The power supply includes: an HF branch including an HF rectifier and a linear voltage regulator, wherein the HF rectifier is configured to be connected to a resonance circuit formed by a HF antenna-coil and a resonance capacitor and wherein the HF rectifier is connected to the linear voltage regulator; a UHF branch including a UHF rectifier and a shunt voltage regulator, wherein the UHF rectifier has a charge pump and is configured to be connected to a UHF antenna and wherein the UHF rectifier is connected to the shunt voltage regulator; and a supply line, wherein the linear voltage regulator and the shunt voltage regulator are both connected to the supply line of the power supply.

Embodiments are directed to rectifiers using a single bias current or bias current path to bias multiple rectifying elements. A rectifier that has multiple rectifier stages coupled together serially includes a bias current path coupled to each of the rectifier stages. Thee bias current path is configured to simultaneously bias rectifying elements in each of the rectifier stages by using a bias current to bias a first rectifying element and reusing the bias current to bias other rectifying elements.

A power control unit is provided to control the efficiency of a charge pump converter having a first input terminal and a second input terminal, a primary attenuator and a secondary attenuator between a first input terminal and the second input terminal, a first output terminal, a second output terminal, a secondary attenuator controlling terminal and a primary attenuator controlling terminal to be plugged to the power control unit. The primary attenuator controlling terminal and the secondary attenuator controlling terminal are to attenuate or amplify a signal of the first input terminal and the second input terminal.

The present disclosure provides a circuit and a method for improving energy harvest for an RFID tag with a temperature sensor, where an instruction command sent by a card reader includes a modulated part to invoke temperature sensor functions, and an unmodulated constant-envelop RF signal part with an extended time of duration to charge a switched additional energy storage capacitor embedded in the circuit. The switched additional energy storage capacitor is connected to the circuit upon a mode control signal corresponding to the sensor operation mode of the RFID tag. Thus, the RFID tag with the temperature sensor is ensured to conform to the timing window protocol for regular downlink operations, and at the same time, is capable of meeting higher energy demand for a high accuracy temperature sensor operation.

Various embodiments may include an identification device comprising: a data memory storing a piece of information containing an identification; a processor generating a signal indicating the piece of information; an optical-to-electrical energy converter supplying power for the processor and converting electromagnetic radiation from the surroundings into an electric current feeding the processor via a power connection; an output device with a data connection to the processor for transmitting the signal; and an executable program stored in the processor for reading an input signal transmitted via the power connection and superimposed on the electrical current.

An open loop control unit is provided to monitor an output power of a charge pump converter having an input impedance and a first input impedance controlling terminal configured to be plugged to the open loop control unit and modify the input impedance. The open loop control unit includes at least a reference circuit to sense the output power of the charge pump converter and at least one control circuit to receive the difference value, establish a trim value, and send the trim value to the impedance controlling terminal so as to modify the input impedance.

A power control unit is provided to monitor the output power of a charge pump converter having an input impedance and an input impedance controlling terminal to be plugged to the power control unit and modify the input impedance. The power control unit includes a control circuit sense the output power of the charge pump converter and a control unit to receive the sensed power value, establish a control value, and send the control value to the impedance controlling terminal so as to modify the input impedance.

Embodiments are directed to rectifiers using a single bias current or bias current path to bias multiple rectifying elements. A rectifier that has multiple rectifier stages coupled together serially includes a bias current path coupled to each of the rectifier stages. Thee bias current path is configured to simultaneously bias rectifying elements in each of the rectifier stages by using a bias current to bias a first rectifying element and reusing the bias current to bias other rectifying elements.