Abstract: A down converter, including first and second biasing circuits, mixer, and transformer coupled to receive amplifier output signal. The first and second biasing circuits each include a biasing transistor and a first and second node, respectively. Mixer includes first and second transistors coupled to first node and third and fourth transistors coupled to second node. The second and fourth transistors are coupled to a third node. The first and third transistors are coupled to a fourth node. Mixer also includes a first resistor coupled to the fourth node and a supply voltage node and a second resistor coupled to the third node and a supply voltage node. Transformer includes a primary winding coupled to receive the amplifier output signal and to a supply voltage and a secondary winding coupled to mixer and first biasing circuit at first node and coupled to mixer and second biasing circuit at second node.

Abstract: Described examples include a method for operating a receiver including receiving an output of an in-phase IF path; receiving an output of a quadrature IF path; measuring a blocker power on a plurality of IF channels on at least one of the in-phase path and the quadrature path within a fraction of a symbol interval; selecting a selected one of the plurality of IF channels having a low blocker power as an image channel; and providing a local oscillator output to the in-phase IF path and quadrature IF path operate corresponding to the image channel, such that a frequency of the local oscillator output is changed within a fraction of the symbol interval.

Abstract: The disclosure provides a frequency synthesizer. It includes a PFD that generates an up signal and a down signal in response to a reference signal and a feedback signal. A charge pump generates a control voltage in response to the up signal and the down signal. A low pass filter generates a filtered voltage in response to the control voltage. An oscillator circuit generates an output signal in response to the filtered voltage. A feedback divider is coupled between the oscillator circuit and the PFD, and divides the output signal by a first integer divider to generate the feedback signal. A sigma delta modulator (SDM) generates a second integer divider in response to the feedback signal, the reference signal, the output signal and the first integer divider. A digital filter is coupled between the SDM and the feedback divider, and filters quantization noise associated with the SDM.

Abstract: At least some embodiments are directed to a receiver system that comprises a first oscillation module configured to provide oscillating signals of differing frequencies and a second oscillation module configured to provide other oscillating signals of the differing frequencies. The second oscillation module is configured to produce less noise than the first oscillation module. A controller is coupled to the first and second oscillation modules and configured to selectively activate and deactivate each of the first and second oscillation modules based on signal strengths of primary signals received via a wireless medium and based on signal strengths of interference signals received via the wireless medium.

Abstract: A method of charging a power harvested supply in an electronic communication device, which can be an NFC (near field communication) device. The power harvested supply in the electronic communication device is charged without causing dV/V violation and avoids false wake up. An RF (radio frequency) field is received at the antenna of the electronic communication device. A differential voltage is generated from the RF field at a first tag pin and a second tag pin of the electronic communication device. A bandgap reference voltage and a reference current are generated in response to the differential voltage. A shunt current is generated in response to the differential voltage and the bandgap reference voltage. A bank of switching devices is activated if the shunt current is more than the reference current.

Abstract: The disclosure provides a frequency synthesizer. It includes a PFD that generates an up signal and a down signal in response to a reference signal and a feedback signal. A charge pump generates a control voltage in response to the up signal and the down signal. A low pass filter generates a filtered voltage in response to the control voltage. An oscillator circuit generates an output signal in response to the filtered voltage. A feedback divider is coupled between the oscillator circuit and the PFD, and divides the output signal by a first integer divider to generate the feedback signal. A sigma delta modulator (SDM) generates a second integer divider in response to the feedback signal, the reference signal, the output signal and the first integer divider. A digital filter is coupled between the SDM and the feedback divider, and filters quantization noise associated with the SDM.

Abstract: An electronic communication device includes an antenna configured to receive a radio frequency (RF) signal and generate a differential current signal. A mixer circuit is configured to downconvert a differential voltage to generate an output voltage. The differential voltage is generated from the differential current signal, and the output voltage is used for detecting the RF signal.

Abstract: A digital shunt regulator receives a radio frequency (RF) signal at an antenna which generates a differential output signal over a differential path. A peak detector is coupled to the antenna and receives the differential output signal over the differential path. A first comparator receives a voltage output of the peak detector and a first voltage. A second comparator receives the voltage output of the peak detector and a second voltage. A digital state machine receives an output of the first comparator and an output of the second comparator. A plurality of shunt NMOS transistors receives an output of the digital state machine. The digital state machine is configured to control the number of shunt NMOS transistors that are activated to maintain the voltage output of the peak detector between the first voltage and the second voltage.

Abstract: An electronic communication device includes an antenna configured to receive a radio frequency (RF) signal and generate a differential current signal at a first tag pin and a second tag pin. A first variable resistor is coupled to the first tag pin and a second variable resistor is coupled to the second tag pin. A mixer circuit is coupled across the first variable resistor and the second variable resistor and is configured to generate an output voltage. The output voltage is used for RF signal detection at all RF signal levels.

Abstract: A digital shunt regulator receives a radio frequency (RF) signal at an antenna which generates a differential output signal over a differential path. A peak detector is coupled to the antenna and receives the differential output signal over the differential path. A first comparator receives a voltage output of the peak detector and a first voltage. A second comparator receives the voltage output of the peak detector and a second voltage. A digital state machine receives an output of the first comparator and an output of the second comparator. A plurality of shunt NMOS transistors receives an output of the digital state machine. The digital state machine is configured to control the number of shunt NMOS transistors that are activated to maintain the voltage output of the peak detector between the first voltage and the second voltage.

Abstract: An electronic communication device includes an antenna configured to receive a radio frequency (RF) signal and generate a differential current signal at a first tag pin and a second tag pin. A first variable resistor is coupled to the first tag pin and a second variable resistor is coupled to the second tag pin. A mixer circuit is coupled across the first variable resistor and the second variable resistor and is configured to generate an output voltage. The output voltage is used for RF signal detection at all RF signal levels.

Abstract: A digital shunt regulator receives a radio frequency (RF) signal at an antenna which generates a differential output signal over a differential path. A peak detector is coupled to the antenna and receives the differential output signal over the differential path. A first comparator receives a voltage output of the peak detector and a first voltage. A second comparator receives the voltage output of the peak detector and a second voltage. A digital state machine receives an output of the first comparator and an output of the second comparator. A plurality of shunt NMOS transistors receives an output of the digital state machine. The digital state machine is configured to control the number of shunt NMOS transistors that are activated to maintain the voltage output of the peak detector between the first voltage and the second voltage.

Abstract: A method of coupling a first port of a single antenna to a first coupling circuit and a second port of the single antenna to a second coupling circuit. The method includes coupling a wireless charging unit to the first coupling unit and coupling an NFC transceiver block to the second coupling circuit. The method further includes isolating the single antenna from the wireless charging unit during a time interval when the NFC transceiver block is operational and isolating the single antenna from the NFC transceiver block during a time interval when the wireless charging unit is operational.

Abstract: A method of charging a power harvested supply in an electronic communication device, which can be an NFC (near field communication) device. The power harvested supply in the electronic communication device is charged without causing dV/V violation and avoids false wake up. An RF (radio frequency) field is received at the antenna of the electronic communication device. A differential voltage is generated from the RF field at a first tag pin and a second tag pin of the electronic communication device. A bandgap reference voltage and a reference current are generated in response to the differential voltage. A shunt current is generated in response to the differential voltage and the bandgap reference voltage. A bank of switching devices is activated if the shunt current is more than the reference current.

Abstract: A digital shunt regulator receives a radio frequency (RF) signal at an antenna which generates a differential output signal over a differential path. A peak detector is coupled to the antenna and receives the differential output signal over the differential path, A first comparator receives a voltage output of the peak detector and a first voltage. A second comparator receives the voltage output of the peak detector and a second voltage. A digital state machine receives an output of the first comparator and an output of the second comparator. A plurality of shunt NMOS transistors receives an output of the digital state machine. The digital state machine is configured to control the number of shunt NMOS transistors that are activated to maintain the voltage output of the peak detector between the first voltage and the second voltage.

Abstract: An electronic communication device includes an antenna configured to receive a radio frequency (RF) signal and generate a differential current signal at a first tag pin and a second tag pin. A first variable resistor is coupled to the first tag pin and a second variable resistor is coupled to the second tag pin. A mixer circuit is coupled across the first variable resistor and the second variable resistor and is configured to generate an output voltage. The output voltage is used for RF signal detection at all RF signal levels.

Abstract: Several circuits and methods for field-based communication are provided. In an embodiment, a field-based communication circuit includes a receiver circuit, a detection circuit and a control circuit. The receiver circuit is configured to receive a field input signal from a field source. The detection circuit includes a voltage detection circuit and a current detection circuit configured to detect a voltage signal and a current signal, respectively associated with the field input signal. The control circuit is configured to trigger a selection of one of the voltage detection circuit and the current detection circuit based on a detection of a signal magnitude of one of the voltage signal and the current signal relative to at least a first predetermined threshold level, wherein the selection of one of the voltage detection circuit and the current detection circuit facilitates a demodulation of one of the voltage signal and the current signal.

Abstract: A circuit includes an antenna, and a pair of transceivers. A first transceiver in the pair is connected to the antenna via a first pair of feed-points, and is designed to transmit and receive signals in a first band of frequencies. A second transceiver in the pair is connected to the antenna via a second pair of feed-points, and is designed to transmit and receive signals in a second band of frequencies. The first band and the second band are non-overlapping frequency bands. The first pair of feed-points is located at a voltage null point of the antenna with respect to the second pair of feed-points. The second pair of feed-points is located at a voltage null point of the antenna with respect to the first pair of feed-points. The first transceiver and the second transceiver are, thus, enabled to simultaneously transmit and/or receive corresponding signals using the same antenna.

Abstract: A single-antenna solution is provided for near-field and far-field communication in wireless devices. In an embodiment, a first transceiver block generates a first transmit signal to be transmitted using radiative techniques. A second transceiver block generates a second transmit signal to be transmitted using inductive coupling. The first and second transceiver blocks are coupled to a same antenna for transmitting the first transmit signal using radiative coupling, and the second transmit signal using inductive coupling. The first transceiver block and the second transceiver block operate according to time division multiplexing, and in an embodiment corresponding to an FM transceiver and an NFC transceiver.

Abstract: Several circuits and methods for field-based communication are provided. In an embodiment, a field-based communication circuit includes a receiver circuit, a detection circuit and a control circuit. The receiver circuit is configured to receive a field input signal from a field source. The detection circuit includes a voltage detection circuit and a current detection circuit configured to detect a voltage signal and a current signal, respectively associated with the field input signal. The control circuit is configured to trigger a selection of one of the voltage detection circuit and the current detection circuit based on a detection of a signal magnitude of one of the voltage signal and the current signal relative to at least a first predetermined threshold level, wherein the selection of one of the voltage detection circuit and the current detection circuit facilitates a demodulation of one of the voltage signal and the current signal.