Abstract: An aspect relates to an apparatus including a radio frequency (RF) signal power detector. The RF signal power detector includes a first current source configured to generate a first current based on a power level of a first RF signal; a transimpedance amplifier (TIA) configured to generate a first voltage based on the first current, wherein the TIA is coupled between a first upper voltage rail and a lower voltage rail; and a second current source configured to generate a second current related to the first current, wherein the first and second current sources are coupled in series between a second upper voltage rail and the lower voltage rail.

Abstract: A power amplifier circuit includes a first transistor having an emitter electrically connected to a common potential, a base to which a first high-frequency signal is input, and a collector from which a third high-frequency signal is output; a second transistor having an emitter electrically connected to the common potential, a base to which a second high-frequency signal is input, and a collector from which a fourth high-frequency signal is output; a first capacitance circuit electrically connected between the collector of the second transistor and the base of the first transistor; and a second capacitance circuit electrically connected between the collector of the first transistor and the base of the second transistor.

Abstract: A circuit is disclosed, in accordance with some embodiments. The circuit includes a transistor stage, a resistive element, a first tunable capacitive element and a second tunable capacitive element. The transistor stage includes a first input/output terminal and a second input/output terminal. The resistive element is connected to the transistor stage. The first tunable capacitive element is connected in parallel with the resistive element. The second tunable capacitive element is connected to the second input/output terminal of the transistor stage.

Abstract: A subharmonic switching digital power amplifier system includes a power amplifier core that includes at least one power amplifier operable in a power back-off region and a power supply providing at least one operating voltage to the power amplifier. Characteristically, the power amplifier is toggled at a subharmonic component of a carrier frequency (Fc) to achieve power back-off wherein the power amplifier is operated in a voltage mode or current mode driver. Multi-subharmonics can be used to further enhance the power back-off efficiency. A switching digital power amplifier system employing phase interleaving is also provided.

Abstract: An example process includes reducing a quality factor of a first tunable bandpass filter, used, for example, in a low-noise amplifier stage of a polar receiver. A first wideband test signal centered at a desired center frequency of a second tunable bandpass filter is received. A frequency response of the second tunable bandpass filter to the first wideband test signal is estimated using a Fast Fourier Transform (FFT) signal processor. At least a resonant frequency or a quality factor of the second tunable bandpass filter are calibrated based at least in part on a portion of the estimated frequency response of the second tunable bandpass filter obtained from the FFT signal processor. Frequency response characteristics of the first tunable bandpass filter may be similarly tuned in accordance with the example process.

Abstract: Overcoming parasitic capacitances in RF integrated circuits is a challenging problem. The disclosed methods and devices provide solution to such challenge. Devices based on tunable capacitive elements that can be implemented with switch RF stacks are also disclosed.

Abstract: A power amplifier module includes an amplifier that amplifies an input signal and outputs the amplified signal, a harmonic termination circuit that is disposed subsequent to the amplifier and that attenuates a harmonic component of the amplified signal, the harmonic termination circuit including at least one field effect transistor (FET), and a control circuit that controls a gate voltage of the at least one FET to adjust a capacitance value of a parasitic capacitance of the at least one FET. The control circuit adjusts the capacitance value of the parasitic capacitance of the at least one FET, and thereby a resonance frequency of the harmonic termination circuit is adjusted.

Abstract: A multi-channel capacitive sensor for measuring the capacitances of a plurality of sense electrodes to a system reference potential. The sensor comprises a sample capacitor having a first terminal and a second terminal, a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. The sample capacitor and diodes are coupled to a control circuit, e.g. implemented in a microcontroller. The control circuit is operable to apply a drive signal, e.g. a series of voltage pulses, to the first terminal of the sample capacitor while simultaneously applying a bias signal to the second terminal of one or other of the diodes to prevent the diode from conducting the drive signal.

Abstract: An apparatus includes an amplifying circuit configured to include stacked first and second transistors, and to amplify a signal input from an input terminal during an operation in an amplifying mode, and provide the amplified signal to an output terminal, and a negative feedback circuit comprising first to nth sub-negative feedback circuits, each corresponding to a separate gain mode included in the amplifying mode, wherein the negative feedback circuit is configured to provide a variable resistance value to determine a negative feedback gain based on each of the separate gain modes.

Abstract: Disclosed herein are signal amplifiers that provide impedance adjustments for different gain modes. The impedance adjustments are configured to result in a constant real impedance for an input signal at the amplifier. The amplifiers include a scalable impedance adjustment circuit that adjusts inductance and/or a device width to compensate for changes in the total impedance presented to an input signal. By providing impedance adjustments, the amplifiers reduce losses and improve performance by improving impedance matching over a range of gain modes.

Abstract: A focus assist circuit for a viewfinder, including a video amplifier configured to amplify a video signal, a video gain controller configured to adjust gain of the video amplifier to provide peaking headroom, and a peaking processor configured to adjust the amplified video signal. The focus assist circuitry may facilitate focusing a camera lens by proving peaking headroom for a peaking signal that is combined with an amplified signal. The peaking headroom limits the gain applied to a video signal in order to reduce distortions in the peaks. A user interface may include input controls configured to limit the gain of the of a video amplifier.

Abstract: According to one embodiment, a low noise amplifier (LNA) circuit includes a first stage which includes: a first transistor; a second transistor coupled to the first transistor; a first inductor coupled in between an input port and a gate of the first transistor; and a second inductor coupled to a source of the first transistor, where the first inductor and the second inductor resonates with a gate capacitance of the first transistor for a dual-resonance. The LNA circuit includes a second stage including a third transistor; a fourth transistor coupled between the third transistor and an output port; and a passive network coupled to a gate of the third transistor. The LNA circuit includes a capacitor coupled in between the first and the second stages, where the capacitor transforms an impedance of the passive network to an optimal load for the first amplifier stage.

Abstract: Low-power multi-stage amplifiers are provided for capacitive reading of low-amplitude and low-frequency signals. An exemplary multi-stage amplifier comprises a plurality of amplification stages, wherein each of the amplification stages comprises an amplifying transistor and an active load, wherein substantially all of the amplification stages have one or more of an increasing DC bias level and a decreasing DC bias level relative to a prior stage, and wherein an output of a given one of the amplification stages is directly applied as an input to a subsequent one of the amplification stages.

Abstract: A radio frequency (RF) transmit-receive switch has an antenna port, first and second transmit differential ports and first and second receive differential ports. Transmit transistor switches are connected to the transmit differential ports. Primary and secondary windings of a transmit coupled inductor transformer are connected to the transmit transistor switches. Receive transistor switches are connected to the receive differential ports. Primary and secondary windings of a receive coupled inductor transformer are connected to the receive transistor switches. A first balun inductive winding is connected to the antenna port, and a second balun inductive winding is connected to the transistor switches.

Abstract: The invention describes a broadband matching network for coupling to an output of an amplifying device for amplifiers with a nominal operating frequency between 1 MHz and 100 MHz. The broadband matching network comprises a planar transformer with a primary winding arranged on a primary side of the broadband matching network and a secondary winding arranged on a secondary side of the broadband matching network. The primary winding is arranged to be electrically connected to the output of the amplifying device. The broadband matching network is characterized by a center frequency and a bandwidth with a frequency range of at least +/?3%. A first parallel resonance frequency and a second parallel resonance frequency of the broadband matching circuit are arranged around the series resonance frequency such that a frequency dependence of a load impedance provided by the broadband matching network for the amplifying device is reduced.

Abstract: Radio frequency (RF) amplifiers, such as power amplifiers, are provided herein. In certain configurations, an RF amplifier includes an input terminal that receives an RF input signal, an output terminal that provides an RF output signal, an injection-locked oscillator driver stage that amplifies the RF input signal to generate an injection-locked RF signal, and a stacked output stage that further amplifies the injection-locked RF signal to generate the RF output signal. The stacked output stage includes a stack of at least a first transistor and a second transistor in series with one another. Thus, the stacked output stage is operable over a wide range of supply voltage to overcome the relatively low breakdown voltages of scaled transistors. Moreover, the injection-locked oscillator driver stage provides the RF amplifier with excellent power efficiency, including in applications in which the stacked output stage operates with a supply voltage that is variable.

Abstract: A high-frequency circuit includes a first signal path transmitting a high-frequency signal in a first frequency band group, a second signal path transmitting a high-frequency signal in a second frequency band group, a switch including a common terminal and selection terminals, a first low noise amplifier including an input terminal connected to the first signal path and an output terminal connected to a first selection terminal, a second low noise amplifier including an input terminal connected to the second signal path and an output terminal connected to a second selection terminal, and an output-side impedance matching circuit that matches impedance at the output side of the first low noise amplifier or impedance at the output side of the second low noise amplifier with a predetermined impedance with a conductive state between the a third selection terminal and the common terminal.

Abstract: Systems, methods and apparatus for efficient power control and/or compensation with respect to a varying supply voltage of an RF amplifier for amplification of a constant envelope RF signal are described. A reduction in a size of a pass device of an LDO regulator is obtained by removing the pass device of the LDO regulator from a main current conduction path of the RF amplifier. Power control and/or compensation is provided by varying one or more gate voltages to cascoded transistors of a transistor stack of the RF amplifier according to a power control voltage. Various configurations for controlling the gate voltages are presented by way of a smaller size LDO regulator or by completely removing the LDO regulator. In a case where a supply voltage to the transistor stack varies, such as in a case of a battery, a compensation circuit is used to adjust the power control voltage in view of a variation of the supply voltage, and therefore null a corresponding drift/variation in output power of the RF amplifier.

Abstract: A circuit with co-matching topology for transmitting and receiving RF signals, said circuit comprising: a first sub-circuit comprising a first inductive component and a first capacitive component to form a low-pass filter for transmitting a first RF signal from a first amplifier to an antenna, wherein the first inductive component is coupled to a ground via a first switch; and a second sub-circuit comprising a second inductive component and a second capacitive component for receiving a second RF signal from the antenna to an input terminal of a second amplifier, wherein said input terminal of the second amplifier is coupled to the ground via a second switch; wherein when the first amplifier is transmitting the first RF signal, the first switch is turned off and the second switch is turned on, and wherein when the second amplifier is receiving the second RF signal, the first switch is turned on and the second switch is turned off.

Abstract: An front end module (FEM) integrated circuit (IC) architecture that uses the same LNA in each of several frequency bands extending over a wide frequency range. In some embodiments, switched impedance circuits distributed throughout the FEM IC allow selection of the frequency response and impedances that are optimized for particular performance parameters targeted for a desired device characteristic. Such switched impedance circuits tune the output and input impedance match and adjust the gain of the LNA for specific operating frequencies and gain targets. In addition, adjustments to the bias of the LNA can be used to optimize performance trade-offs between the total direct current (DC) power dissipated versus radio frequency (RF) performance. By selecting appropriate impedances throughout the circuit using switched impedance circuits, the LNA can be selectively tuned to operate optimally at a selected bias for operation within selected frequency bands.

Abstract: An apparatus includes an amplifier and a first inductor coupled to an input of the amplifier. The apparatus also includes a second inductor that is inductively coupled to the first inductor and that couples the amplifier to a first supply node. The apparatus further includes a third inductor that is inductively coupled to the first inductor and to the second inductor and that couples the amplifier to a second supply node.

Abstract: An inductor isolation apparatus and method to reduce interaction between inductors on an integrated circuit.

Abstract: An apparatus includes amplification circuitry configured to amplify a radio frequency (RF) signal. The apparatus also includes differential inductors coupled to an output of the amplification circuitry. The differential inductors include a first inductor serially coupled to a second inductor, and the differential inductors are configured to filter the RF signal and to provide a differential output.

Abstract: An adaptive power amplifier that may be used in a wireless communication device is configured to adjust its load line or output impedance, the number of active amplifier cells in each amplification stage, the bias of the active amplifiers, and the supply voltage input capacitive load in accordance with a supply voltage modulation type provided to the power amplifier. The supply voltage modulation types include ET, APT, DC-DC, dual, multi-state or fixed voltage supply voltages. A supply voltage converter, signaled by a baseband processor, generates the selected type of supply voltage modulation for the adaptive power amplifier. The baseband processor may also provide a control interface signal to a controller within the adaptive power amplifier.

Abstract: Embodiments of a Doherty power amplifier that maintain efficiency over a large operating average power range are disclosed. In one embodiment, the Doherty power amplifier includes reconfigurable main and auxiliary output matching networks and a fixed combining network. The reconfigurable main and auxiliary output matching networks can be reconfigured such that together the reconfigurable main output matching network, the reconfigurable auxiliary output matching network, and the fixed combining network provide proper load modulation for multiple different back-off power levels. As a result, the Doherty power amplifier maintains high efficiency over an extended back-off power level range.

Abstract: A transmit-receive switching circuit provided between a transmitter circuit configured to generate a transmission signal to be transmitted from an antenna and a receiver circuit configured to receive a reception signal received by the antenna, a transistor input control circuit configured to make the transmitter generate a transmission signal by an amplifying operation of a transistor in an output stage of the transmitter circuit when the transmission signal is transmitted from the antenna, and to short-circuit an output terminal of the transmitter circuit to a ground voltage when the reception signal is received by the antenna.

Abstract: A radio frequency system includes a power amplifier that outputs a radio frequency signal to a matching network via a transmission line between the power amplifier and the matching network. A sensor monitors the radio frequency signal and generates first sensor signals based on the radio frequency signal. A distortion module determines a first distortion value according to at least one of (i) a sinusoidal function of the first sensor signals and (ii) a cross-correlation function of the first sensor signals. A first correction circuit (i) generates a first impedance tuning value based on the first distortion value and a first predetermined value, and (ii) provides feedforward control of impedance matching performed within the matching network including outputting the first impedance tuning value to one of the power amplifier and the matching network.

Abstract: An exemplary embodiment of the present invention provides an adaptive power amplifier comprising a transistor, a resistive load, and a tuning circuit. The transistor has a drain, a source, and a gate. The resistive load can be electrically coupled to the drain. The tuning circuit can be electrically coupled to the drain in parallel with the transistor. The tuning circuit can comprise an inductor and a capacitive element. The inductor and capacitive element can be in series connection.

Abstract: A power amplifier configured to boost an AC signal. The power amplifier includes a first transistor, a second transistor, a first inductor connected between the first transistor and a voltage source, and a second inductor connected between the second transistor and ground. A first phase conditioner arranged at an input of the first transistor is configured to condition a phase of the AC signal such that the AC signal as received by the first transistor is out of phase with respect to the AC signal as received by the first inductor. A second phase conditioner arranged at an input of the second transistor is configured to condition a phase of the AC signal such that the AC signal as received by the second transistor is out of phase with respect to the AC signal as received by the second inductor.

Abstract: A multi-stage amplifier is provided that uses tunable transmission lines, as well as a calibration method for the multi-stage amplifiers. A multi-stage amplifier, comprises a plurality of tunable amplification stages, wherein each of the tunable amplification stages comprises a tunable resonator based on a transmission line having a tunable element. The tunable elements may vary a capacitance or an inductance to tune a frequency of an applied signal. A calibration method is provided for a multi-stage amplifier having a plurality of transmission lines, an input stage and an output stage. The multi-stage amplifier is calibrated by generating a signal to determine a frequency for a substantially maximum power; generating an error signal by comparing the frequency for the substantially maximum power with a desired frequency; varying a digital control code applied to each of the tunable transmission lines, input stage and output stage until the error signal satisfies predefined criteria.

Abstract: Radio frequency (RF) front-end circuitry that includes control circuitry and an RF filter structure that includes a plurality of resonators are disclosed. In one embodiment, a first tunable RF filter path is defined by a first set of the plurality of resonators such that the first tunable RF filter path has a first amplitude and a first phase. A second tunable RF filter path is defined by a second set of the plurality of resonators such that the second tunable RF filter path has a second amplitude and a second phase. To provide antenna diversity and/or beam forming/beam steering, the control circuitry is configured to set a first amplitude difference between the first amplitude and the second amplitude to approximately a first target amplitude difference and set a first phase difference between the first phase and the second phase to approximately a first target phase difference.

Abstract: A method and system for designing and implementing a reconfigurable Doherty amplifier system are disclosed. In one embodiment, a design method includes determining, using a processor, a first set of ABCD transmission parameters of a first output compensation network in a main path of a Doherty amplifier for the case where an auxiliary amplifier of the Doherty amplifier is off. The method further includes determining, using a processor, a second set of ABCD transmission parameters of a second output compensation network in an auxiliary path of the Doherty amplifier based on the first set of ABCD transmission parameters.

Abstract: A low noise amplifier including a variable gain amplifier stage configured to accept an input signal and to provide a load driving signal; a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component when the load driving signal is of a magnitude large enough to decreases a transconductance of the cross-coupled transistor pair; and, a controller circuit configured to tune the bandpass filter. The filter can be tuned in respect to the frequency and the quality factor Q.

Abstract: A narrow band receiver or transceiver for processing electrical signals. The narrow band receiver or transceiver includes an amplifier, a voltage controlled oscillator and a tuning assembly comprising at least one control loop for tuning of the voltage controlled oscillator. At least a gain control of the amplifier is coupled to the control loop for simultaneously tuning the output amplitude of the voltage controlled oscillator and the gain of the amplifier. A compensation of the effect of variation on the gain of the amplifier, which includes an LC tank circuit, is performed by using an information in another LC tank circuit of the voltage controlled oscillator in the control loop.

Abstract: A method, device and system is disclosed for high efficiency power amplification of a signal over a broad range of output power. Two broad-banded, parallel-tuned class E power amplifiers are combined through a lossless half wave transmission line combiner and configured to operate in an outphased arrangement to permit amplitude modulation. Asymmetrical shunt tuned switches are tuned for efficient amplitude modulation while asymmetrical drain inductors provide enhanced efficiency at outphased conditions over that of a symmetrical circuit. The drain source inductors and transmission components are tuned for maximum efficiency at full power output and for minimum dissipation a zero power output. At zero degrees outphasing, the circuit operates as a conventional Class-E power amplifier. However, at 180 degrees outphasing, each quarterwave line in the combiner reflects back all incident power, permitting the circuit to operate as an unloaded resonant switching circuit.

Abstract: A circuit for amplifying the power of signal, the circuit comprising a power amplifier, a transformer and a load; wherein the transformer comprises a primary inductor and a secondary inductor, the first inductor being coupled to, and capable of being driven by, the power amplifier, and the secondary inductor coupled to, and capable of driving, the load; wherein a first one of the primary and secondary inductors is a variable inductor whose inductance is variable responsive to a control input in order to change the output power of the amplifier.

Abstract: A cascaded arrangement of resonant tanks capable of widening frequency selection and tuning within an RF circuit is presented. Moreover, usage of DTC allows for larger frequency tuning per tank as well as handling of higher voltage swings while maintaining high linearity across the tuning range.

Abstract: An amplifier includes a negative gain amplifier, a load element, and a transconductance device. The negative gain amplifier has an input and an output. The load element has a first terminal coupled to a power supply voltage terminal, and a second terminal. The transconductance device has a first current electrode coupled to the second terminal of the load element, a control electrode coupled to the output of the negative gain amplifier, and a second current electrode coupled to the input of the negative gain amplifier.

Abstract: Embodiments are directed to capacitance compensation via a compensation device coupled to a gain device to compensate for a capacitance change occurring due to an input signal change, along with a controller coupled to the compensation device to receive the input signal and to control an amount of compensation based on the input signal. In some embodiments, banks may be formed of multiple compensation devices, where each of the banks has a different size and is coupled to receive a different set of bias voltages.

Abstract: According to an embodiment, a power amplifier includes a variable passive element and a comparator. The variable passive element is connected directly or indirectly to a first terminal of a switch element and serves to increase or reduce a resonant frequency of the amplifier. The comparator compares a voltage of interest with a reference voltage and outputs a control voltage for the variable passive element based on a difference between the voltage of interest and the reference voltage.

Abstract: A power amplifier circuit, comprising: an amplifier for receiving an input signal to be amplified; a power input for coupling the amplifier to a power supply; and a transformer for providing the amplified signal from the amplifier to a load, comprising a primary inductor and a secondary inductor. The power amplifier circuit is characterized by: a first capacitor coupled in parallel with the primary inductor; and a second capacitor coupled in parallel with the secondary inductor; wherein at least one of the first and second capacitors has a variable capacitance.

Abstract: A differential amplifying circuit includes: two metal oxide semiconductor transistors to form a differential pair and receive a differential signal; a plurality of capacitance elements coupled in series between drains of the two metal oxide semiconductor transistors; and an inductance circuit coupled between at least one connection node of the plurality of capacitance elements and a bias power terminal.

Abstract: A method is provided for process, voltage, temperature (PVT) stable transfer function calibration in a differential amplifier. The gain resistors of a differential amplifier are initially selected to achieve a flat amplitude transfer function in the first frequency band. After calibration, the degeneration capacitor is connected and tuned until a peaked amplitude transfer function is measured, which is resistant to variations in PVT. As an alternative, the degeneration capacitor is not disconnected during initial calibration. Then, the gain resistors and the degeneration capacitor values are selectively adjusted until the first peaked amplitude transfer function is obtained. The peaked amplitude transfer function remains even more stable to variations in PVT than the flat amplitude calibration method.

Abstract: A differential amplifying circuit includes: two metal oxide semiconductor transistors to form a differential pair and receive a differential signal; a plurality of capacitance elements coupled in series between drains of the two metal oxide semiconductor transistors; and an inductance circuit coupled between at least one connection node of the plurality of capacitance elements and a bias power terminal.

Abstract: An impedance matching circuit with at least one tunable notch filter for a power amplifier is disclosed. The power amplifier amplifies an input radio frequency (RF) signal and provides an amplified RF signal. The impedance matching circuit performs output impedance matching for the power amplifier and includes at least one tunable notch filter. Each tunable notch filter has a notch that can be varied in frequency to provide better attenuation of an undesired signal. The at least one tunable notch filter attenuates at least one undesired signal in the amplified RF signal. The at least one tunable notch filter may include (i) a first tunable notch filter to attenuate a first undesired signal at a second harmonic of the amplified RF signal and/or (ii) a second tunable notch filter to attenuate a second undesired signal at a third harmonic of the amplified RF signal.

Abstract: Apparatus and methods are also disclosed related to tuning a quality factor of an LC circuit. In some implementations, the LC circuit can be embodied in a low-noise amplifier (LNA). A quality factor adjustment circuit can increase and/or decrease conductance across the LC circuit. This can stabilize a parasitic resistance in parallel with the LC circuit. In this way, a gain of the LC circuit can be stabilized.

Abstract: An amplifier includes a first switch and a second switch each having a first terminal and a second terminal. The first terminals of the first and second switches respectively communicate with a first tank circuit and a second tank circuit. The second terminal of the second switch communicates with the second terminal of the first switch. A first capacitance having a first terminal connected directly to (i) the second terminal of the first switch and (ii) the second terminal of the second switch. A second terminal of the first capacitance is connected directly to a first input voltage of the amplifier. A first load is connected across (i) the first terminal of the first switch and (ii) the first terminal of the second switch. The amplifier generates a first output across the first load.

Abstract: A power amplifier configured to boost an AC signal. The power amplifier includes a first transistor, a second transistor, a first inductor connected between the first transistor and a voltage source, and a second inductor connected between the second transistor and ground. A first phase conditioner arranged at an input of the first transistor is configured to condition a phase of the AC signal such that the AC signal as received by the first transistor is out of phase with respect to the AC signal as received by the first inductor. A second phase conditioner arranged at an input of the second transistor is configured to condition a phase of the AC signal such that the AC signal as received by the second transistor is out of phase with respect to the AC signal as received by the second inductor.

Abstract: A system for compensating impedance mismatch at an output terminal of a RF power amplifier is disclosed. In an embodiment, the system includes a plurality of samplers to measure a first set of parameters associated with an amplified signal being generated by the power amplifier. The first set of parameters is transmitted to a processing unit. The processing unit varies an impedance of an impedance element based on the first set of parameters. The impedance element is connected to the output terminal of the power amplifier.

Abstract: A multi-band, multi-standard programmable power amplifier having tunable impedance matching input and output networks and programmable device characteristics. The impedance of either or both of the impedance matching input and output networks is tunable responsive to one or more control signals. In one example, the programmable power amplifier incorporates a feedback control loop and the control signal(s) are varied responsive to the feedback loop.