In one example, a circuit includes a first node to receive an analog signal that is an amplitude modulated radio-frequency signal for a digital signal. An output node is configured to provide an output signal indicative of rising and falling edges of an envelope of the analog signal. The rising and falling edges are indicative of rising and falling edges of the digital signal. A first current path is disposed between a power supply node and the first node. The first current path includes a first transistor coupled between the first node and a first bias source. The first bias source is coupled between the first transistor and the power supply node. The output node is coupled to a first intermediate node in the first current path between the transistor and the first bias source. A control terminal of the first transistor is coupled to the output node via a feedback network.

In one example, a circuit includes a first node to receive an analog signal that is an amplitude modulated radio-frequency signal for a digital signal. An output node is configured to provide an output signal indicative of rising and falling edges of an envelope of the analog signal. The rising and falling edges are indicative of rising and falling edges of the digital signal. A first current path is disposed between a power supply node and the first node. The first current path includes a first transistor coupled between the first node and a first bias source. The first bias source is coupled between the first transistor and the power supply node. The output node is coupled to a first intermediate node in the first current path between the transistor and the first bias source. A control terminal of the first transistor is coupled to the output node via a feedback network.

A detector circuit in which a change in a detection voltage due to temperature is suppressed is provided. The detector circuit includes a first rectification element having an anode to which an input signal is inputted. A second rectification element has a cathode connected with a cathode of the first rectification element and has an anode connected to an output terminal. A current mirror circuit for supplying a current to the first rectification element and for supplying a current-mirror current of the current to the second rectification element is included in the detector circuit.

A detector circuit in which a change in a detection voltage due to temperature is suppressed is provided. The detector circuit includes a first rectification element having an anode to which an input signal is inputted. A second rectification element has a cathode connected with a cathode of the first rectification element and has an anode connected to an output terminal. A current mirror circuit for supplying a current to the first rectification element and for supplying a current-mirror current of the current to the second rectification element is included in the detector circuit.

A demodulator circuit receives an envelope signal for comparison against a switched reference signal that is generated as a function of the envelope signal and as a function of an output signal of the demodulator circuit. The switched reference signal is filtered by an RC filter prior to comparison. The output signal is dependent on a difference between the filtered switched reference signal and the envelope signal.

A demodulator circuit receives an envelope signal for comparison against a switched reference signal that is generated as a function of the envelope signal and as a function of an output signal of the demodulator circuit. The switched reference signal is filtered by an RC filter prior to comparison. The output signal is dependent on a difference between the filtered switched reference signal and the envelope signal.

The present invention relates to a detector circuit (10) being part of an RFID-device, and comprising: a bias current generator circuit (20) configured to generate an output bias current that is proportional to the square of a temperature-dependent input current, a first and a second FET-devices (21, 22), at least one of the first and the second FET-devices (21, 22) is biased by means of the output bias current of the bias current generator circuit (20) so that it operates in the sub-threshold region, an incoming RF-signal is coupled into at least one of the first and the second FET-devices, a current source (18) for generating a variable threshold current, and a comparator (19) for determining, on the basis of the variable threshold current and the incoming RF-signal, whether the value of the incoming RF-signal exceeds a threshold value.

Described is a circuit for supplying power to an electric load connected to the circuit via an interface, and for receiving desired signals transmitted from the electric load by an amplitude modulation, performed by the electric load, of a carrier signal transmitted from the circuit via the interface, said carrier signal serving to supply power to the electric load, with a carrier signal generator that comprises a direct voltage source and a DC-AC converter downstream of the direct voltage source, and with a demodulator for extraction of desired signals modulated by the electric load on the carrier signal, which circuit has a high efficiency without the use of choke coils. The demodulator is designed to extract the desired signals using a current corresponding to a carrier signal current flowing through a current path of the circuit during a transmission of the desired signals, said carrier signal current flowing across the interface.

Described is a circuit for supplying power to an electric load connected to the circuit via an interface, and for receiving desired signals transmitted from the electric load by an amplitude modulation, performed by the electric load, of a carrier signal transmitted from the circuit via the interface, said carrier signal serving to supply power to the electric load, with a carrier signal generator that comprises a direct voltage source and a DC-AC converter downstream of the direct voltage source, and with a demodulator for extraction of desired signals modulated by the electric load on the carrier signal, which circuit has a high efficiency without the use of choke coils. The demodulator is designed to extract the desired signals using a current corresponding to a carrier signal current flowing through a current path of the circuit during a transmission of the desired signals, said carrier signal current flowing across the interface.

A change in a detection voltage due to the temperature is suppressed. A detector circuit includes: a first rectification element having an anode to which an input signal is inputted; a second rectification element having a cathode connected with a cathode of the first rectification element and having an anode connected to an output terminal; and a current mirror circuit for supplying a current to the first rectification element, and for supplying a current-mirror current of the current to the second rectification element.