Abstract: A receiver circuit includes: a constant current circuit to generate second paired current signals according to first paired current signals; a current splitter circuit to output third paired current signals generated from the second paired current signals, from a first output node and a second output node; and a differential TIA circuit to output paired voltage signals from a first output terminal and a second output terminal, according to the third paired current signals input from a third input node and a fourth input node. The differential TIA circuit includes a first feedback resistor element connected between the third input node and the second output terminal, and a second feedback resistor element connected between the fourth input node and the first output terminal. Average voltages of the first and second output nodes and the first and second output terminals are set to be equivalent to each other.

Abstract: An apparatus includes a first circuit that has a photodetector. The photodetector is reverse-biased by a reverse-bias voltage. A common mode voltage is added to the reverse-bias voltage to provide an offset to the photodetector voltage. A second circuit is coupled to the first circuit to provide the common mode voltage for the first circuit. A third circuit is coupled to the second circuit that includes a first voltage source and a second voltage source having opposite voltages equal to half of the reverse-bias voltage. Each one of the first voltage source and the second voltage source are coupled between separate input and output nodes of input and output ports of the third circuit. The first voltage source and the second voltage source provide the reverse-bias voltage to the first circuit to reverse-bias the photodetector. The third circuit provides a photodetector current at an output of the third circuit.

Abstract: A Doherty power amplifier that includes an input, an output, a main power amplification device connected between the input and the output; and an auxiliary power amplification device connected between the input and the output. The auxiliary power amplification device is arranged in parallel with the main power amplification device. The Doherty power amplifier further includes a first dual-mode impedance transformer connected between the main power amplification device and the output, and a second dual-mode impedance transformer between the auxiliary power amplification device and the output. The first and second dual-mode ITs each is adapted to convert an input impedance of a corresponding one of the main and auxiliary power amplification devices to a load impedance at the output, at two frequencies simultaneously.

Abstract: Power amplifiers including balanced coaxial baluns are described. One example includes first and second amplifiers coupled to a balanced pair of first and second microstrip lines on a circuit board. A balun is coupled between the microstrip lines at a balanced end and between a conductive trace and a ground plane of the circuit board at an unbalanced end of the balun. The balun includes a coaxial balun line and a surface mount balancing inductor. The coaxial line includes center and shield conductors. A first end of the center conductor is coupled to the first microstrip line and a first end of the shield conductor is coupled to the second microstrip line at the balanced end of the balun. The balancing inductor is coupled between the first microstrip line and the ground plane to maintain symmetry for the balanced pair of microstrip lines.

Abstract: An electronic device including a Doherty power amplifier is provided. The electronic device includes a carrier amplifier, a first circuit coupled to an output terminal of the carrier amplifier, a peaking amplifier, a second circuit coupled to an output terminal of the peaking amplifier, and a network circuit. The network circuit includes the Doherty power amplifier and a transmission line for impedance matching with a resonance circuit. The resonance circuit may be disposed between a first area and a second area of the transmission line. The Doherty power amplifier provides an output impedance in a first range distributed based on a frequency within a bandwidth. The network circuit provides a load impedance in a second range distributed based on the frequency within the bandwidth. The first area of the transmission line provides a first phase shift impedance. The second area of the transmission line provides a second phase shift impedance.

Abstract: A Doherty amplifier includes: a first filter circuit to output a first input signal obtained by attenuating an input signal lying in a first frequency band, and to output a second input signal obtained by allowing passage of an input signal lying in a second frequency band; a second filter circuit to output a third input signal obtained by attenuating an input signal lying in the first frequency band, and to output a fourth input signal obtained by attenuating an input signal lying in the second frequency band; a first amplifier to operate as an auxiliary amplifier when receiving the first input signal, and to operate as a main amplifier when receiving the second input signal; and a second amplifier tip operate as the main amplifier when receiving the third input signal, and to operate as the auxiliary amplifier when receiving the fourth input signal.

Abstract: Systems and methods for analog predistortion (APD) in power amplifiers are disclosed. In one aspect, APD may be provided in a front-end module (FEM) of a transmitter. More specifically, the APD may include different predistortions based on where within a frequency band the signal to be distorted is operating (i.e., sub-band APD). The APD in the FEM may further be based on operating conditions such as temperature within the FEM. Still further, the FEM may be configured to apply different APD based on whether or not a baseband processor (BBP) applies digital predistortion (DPD). At a minimum, the provision of the APD may make the operation of a power amplifier in FEM more linear. Further, where DPD is present, the use of the APD may simplify the requirements for the DPD provided in the BBP.

Abstract: A power supply modulation device includes a unit detecting, from a first digital signal, a first amplitude being the amplitude of a first analog signal provided to a first amplifier and detecting, from a second digital signal, a second amplitude being the amplitude of a second analog signal provided to a second amplifier; a unit that calculates a time differential value of a ratio of the first amplitude to a sum of the first amplitude and the second amplitude, and determines, on the basis of the time differential value, whether or not output impedance of a combining circuit that combines together the first analog signal amplified and the second analog signal changes along with a change in power of the combined signal; and a unit that controls a power supply voltage supplied to each of the first amplifier and the second amplifier, on the basis of the determination.

Abstract: A Doherty amplification device includes a distributor to distribute, into first and second signals, an input signal after distortion-compensation, first and second amplifiers, a combiner to combine the amplified first and second signals, and an adjuster between the distributor and the first or second amplifiers and to include a first calculation circuit to obtain a first-characteristic indicating a relationship of a gain of an output signal with respect to reference-power of the input signal, based on the output signal and the input signal, a classification circuit to classify the first-characteristic into regions according to the reference-power, a second calculation circuit to obtain a statistical-value of the gain for each regions, and a determination circuit to set, in the adjuster, a phase-delay at which distortion to be generated in the output signal is minimized, based on the statistical-value, wherein the adjuster adjusts the phase-delay of the first or second signals.

Abstract: A radio-frequency circuit can include a power amplifier, a first bias circuit and a second bias circuit. The power amplifier can include an input terminal used to receive a radio-frequency signal, and an output terminal used to output an amplified radio-frequency signal. The first bias circuit can include a first output terminal coupled to the input terminal of the power amplifier through a common node. The second bias circuit can include a second output terminal and a current adjustment circuit, where the second output terminal can be coupled to the common node, and the current adjustment circuit can include a transistor. The transistor can include a first terminal coupled to the second output terminal, a second terminal used to receive a reference voltage, and a control terminal.

Abstract: In described examples, a circuit includes a reference voltage, a driving circuit with a driving input and a driving output, an output transistor, and a clamp circuit with a clamp input and a clamp output. The output transistor includes a source, a drain, and a gate; the source is coupled to receive the reference voltage. The clamp input is coupled to the driving output and to the gate. The clamp output is coupled to either the driving input or to the driving output, the gate, and the clamp input. The clamp circuit is configured to detect an operating region of the output transistor and to generate a clamping current after the output transistor enters a triode region. The clamping current is selected to prevent an absolute value of a source-gate voltage of the output transistor from equaling or exceeding a gate oxide tunneling voltage of the output transistor.

Abstract: An envelope tracking (ET) integrated circuit (ETIC) operable across wide modulation bandwidth is disclosed. The ETIC includes at least two auxiliary voltage outputs coupled to a high-bandwidth power amplifier circuit that has a lower equivalent capacitance, and thus a higher impedance resonance frequency. The ETIC also includes a pair of ET voltage circuits configured to generate a pair of ET voltages, respectively. To help mitigate potential distortion in the ET voltages, a control circuit is configured to couple the ET voltage circuits exclusively to the auxiliary voltage outputs when the ETIC needs to operate with a high modulation bandwidth (e.g., ?200 MHz). Given the higher impedance resonance frequency of the high-bandwidth power amplifier circuit, it is possible to increase separation between an energy spectrum of a voltage disturbance and an energy spectrum of the high modulation bandwidth, thus helping to reduce the potential distortion in the ET voltages.

Abstract: An amplifier module includes a Doherty amplifier circuit, and the Doherty amplifier circuit includes a first transistor chip constituting a carrier amplifier, a first output signal line configured to transmit a first amplified signal outputted from the carrier amplifier, a second transistor chip constituting a peak amplifier, and a second output signal line configured to transmit a synthetic signal of the first amplified signal and a second amplified signal outputted from the peak amplifier. A direction from a drain terminal of the second transistor chip to a connection, of the first conductor of the first output signal line, with the first bonding wire is the same direction as a direction from the drain terminal of the second transistor chip to a connection, of the second conductor of the second output signal line, with the second bonding wire.

Abstract: A radio frequency circuit assembly architecture is disclosed. An example radio frequency circuit assembly architecture comprises a signal contact and an antenna contact, a power amplifier module connected in a signal path between the signal contact and the antenna contact, the signal path between the power amplifier module and the antenna contact including a differentially signaled portion having a first path and a second path, and a pair of band pass filters, a first band pass filter of the pair of band pass filters being connected in the first path of the differentially signaled portion and a second band pass filter of the pair of band pass filters being connected in the second path of the differentially signaled portion.

Abstract: A pre-compensation method for a pre-compensation circuit coupled to a power amplifier to compensate for nonlinearity of the power amplifier includes performing pre-distortion according to at least one parameter or at least one hyperparameter to convert a first input signal received by the pre-compensation circuit into a first pre-distortion output signal, updating the at least one parameter or the at least one hyperparameter according to Bayesian Optimization, Causal Bayesian Optimization, or Dynamic Causal Bayesian Optimization, and performing pre-distortion according to the at least one parameter updated or the at least one hyperparameter updated to convert a second input signal received by the pre-compensation circuit into a second pre-distortion output signal.

Abstract: A class-D amplifier that amplifies an input signal comprises a control circuit configured to generate a control signal that varies in accordance with a level of the input signal, a first generating circuit configured to generate a first pulse, and a second generating circuit configured to generate a second pulse. A pulse width of the first pulse becomes narrower as the signal level of the input signal becomes smaller, and the pulse width of the first pulse becomes wider as an instantaneous magnitude of the input signal becomes larger. A pulse width of the second pulse becomes narrower as the signal level of the input signal becomes smaller, and the pulse width of the second pulse becomes wider as an instantaneous magnitude of the input signal becomes smaller.

Abstract: In some aspects, the disclosure is directed to methods and systems for an amplifier having common mode feedback inputs. The inputs are coupled to various points within an amplifier wherein a first set of directly coupled common mode feedback inputs join the amplifier one or more nodes, and a second set of capacitively coupled common mode feedback inputs are joined to the amplifier at one or more different nodes.

Abstract: A power amplifier comprises a first transistor, a first transformer, a first variable resistor, a first bias circuit and coupling circuitry configured to couple the first transformer, a first end of the first variable resistor, and a collector of the first transistor at a first node, the first transformer and a second end of the first variable resistor at a second node, and the bias circuit and a base of the first transistor at a third node.

Abstract: A power amplifier device includes an amplification path implemented within a power amplifier package. The amplification path includes input and output package leads, a transistor die with transistor input and output terminals and a power transistor, and a two-stage input impedance matching circuit electrically coupled between the input package lead and the transistor input terminal. The two-stage input impedance matching circuit has a double T-match topology that includes a first resonator coupled to the first input package lead, and a second resonator coupled between the first resonator and the transistor input terminal. The amplification path also includes an output impedance matching circuit coupled between the transistor output terminal and the first output package lead, and a second output harmonic termination circuit coupled to the first output package lead.

Abstract: In some embodiments, stability in power amplifiers can be achieved under high in-band voltage standing wave ratio condition, with an amplifier circuit that includes an amplifier having a first stage and a second stage, with each stage including an input and an output, such that the output of the first stage is coupled to the input of the second stage. The amplifier circuit further includes a stabilizing circuit implemented on the input side of the second stage and configured to provide stability in operation of the amplifier under a high in-band voltage standing wave ratio condition.