A circuit with co-matching topology for transmitting and receiving RF signals for return loss improvement, wherein when transmitting RF signals, the LNA is turned off and the capacitance of an adjustable capacitive component is adjusted for transmitting RF signals, and when receiving RF signals, the power amplifier and the adjustable capacitive component are turned off, wherein a matching network is designed in favor of the LNA for receiving RF signals while the adjustable capacitive component can adjust the overall impedance of the circuit including the matching network that is also used when transmitting RF signals and the adjustable capacitive component for improving the transmitting return loss.

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.

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.

The disclosure provides an amplifier. The amplifier includes a first transistor that receives a first input and generates a first load current. A first output node is coupled to a power supply through a first load resistor. The first load resistor receives the first load current. A first capacitor network is coupled to the first output node and draws a first capacitive current from the first output node. A first current buffer is coupled between the first output node and the first transistor. A current through the first current buffer is a summation of the first load current and the first capacitive current.

A power amplifier circuit includes a first transistor; a first bias circuit that supplies a first bias current or voltage; a capacitor; a first inductor; a second inductor; a second transistor; a second bias circuit that supplies a second bias current or voltage; a third inductor; a third transistor; a third bias circuit that supplies a third bias current or voltage; and a fourth inductor.

Methods and devices addressing design of wideband LNAs with gain modes are disclosed. The disclosed teachings can be used to reconfigure RF receiver front-end to operate in various applications imposing stringent and conflicting requirements. Wideband and narrowband input and output matching with gain modes using a combination of the same hardware and a switching network are also disclosed. The described methods and devices also address carrier aggregation requirements and provide solutions that can be used both in single-mode and split-mode operations.

This disclosure provides systems, methods and apparatuses for characterizing and operating a power amplifier. Before being placed into operation, output phase and output gain characteristics of the power amplifier may be determined over various operating conditions including varying two independent control signals and a supply voltage. The output phase and output gain characteristics may be stored for later retrieval. The power amplifier may be operated by determining a control signal profile for the two independent control signals based on operating conditions and radio-frequency (RF) envelope information associated with an input signal received by the power amplifier. The independent control signals may be generated in accordance with the control signal profile.

This disclosure provides systems, methods and apparatuses for characterizing and operating a power amplifier. Before being placed into operation, output phase and output gain characteristics of the power amplifier may be determined over various operating conditions including varying two independent control signals and a supply voltage. The output phase and output gain characteristics may be stored for later retrieval. The power amplifier may be operated by determining a control signal profile for the two independent control signals based on operating conditions and radio-frequency (RF) envelope information associated with an input signal received by the power amplifier. The independent control signals may be generated in accordance with the control signal profile.

Power amplification units and methods are provided, which use a combiner and an auxiliary signal to feed the power amplifier (PA) with a signal that prevents or reduces operation of higher amplification stages during off periods of the received RF signal. The PA output is delivered through an output matching circuit configured to pass the RF signal and attenuate the auxiliary signal; and the combiner combines the RF signal and the auxiliary signal through respective filters to generate the RF input signal to the PA. An auxiliary signal generator may be configured to generate the auxiliary signal with relation to the RF signal as having a frequency spectrum lower than a cutoff RF frequency. Resulting lower power consumption, particularly in case of low duty cycle RF signals, reduces heating, enables longer battery use and increases reliability performance.

Systems and methods related to power amplification and power supply control. A method of operating a power amplification control system can include receiving, by an interface, a transceiver control signal from a transceiver. The method can further include generating, by a power amplifier control component, a power amplifier control signal based on the transceiver control signal from the transceiver. The method can also include generating, by a power supply control component, a power supply control signal based on one or more of the transceiver control signal from the transceiver or a local control signal from the power amplifier control component.