A communication device includes a power amplifier that generates power signals according to one or more operating bands of communication data, with the amplitude being driven and generated in output stages of the power amplifier. The final stage can include an output passive network that suppresses suppress an amplitude modulation-to-phase modulation (AM-PM) distortion. During a back-off power mode a bias of a capacitive unit of the output power network component can be adjusted to minimize an overall capacitance variation. A output passive network can further generate a flat-phase response between dual resonances of operation.

Disclosed are methods for biasing amplifiers and for manufacturing bias circuits bias for biasing amplifiers. A power amplifier bias circuit can include an emitter follower device and an emitter follower mirror device coupled to form a mirror configuration. The emitter follower device can be configured to provide a bias signal for a power amplifier at an output port. The power amplifier bias circuit can include a reference device configured to mirror an amplifying transistor of an amplifying device of the power amplifier. The emitter follower mirror device can be configured to provide a mirror bias signal to the reference device. A node between the emitter follower device and the emitter follower mirror device can have a voltage of approximately twice a base-emitter voltage (2Vbe) of the amplifying transistor.

A 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 front end circuit 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.

The disclosure relates to technology for shifting a frequency range of a signal. In one aspect, a circuit comprises a frequency mixer, a frequency synthesizer configured to generate an oscillator signal, a programmable driver, and a controller. The programmable driver is configured to receive the oscillator signal from the frequency synthesizer and to provide the oscillator signal to the oscillator input of the frequency mixer. The programmable driver is configured to have a variable drive strength. The controller is configured to control the drive strength of the programmable driver based on a frequency of the oscillator signal to adjust a rise time and a fall time of the oscillator signal at the oscillator input of the frequency mixer.

A digitally controlled variable gain amplifier (VGA) for generating amplification output levels is disclosed. In one aspect, the digitally controlled VGA includes a positive amplification stage including at least two positive amplifiers, and a corresponding negative amplification stage coupled to the positive amplification stage. The negative amplification stage includes at least two negative amplifiers. The positive amplification stage and the corresponding negative amplification stage are digitally controlled by one or more digital codes. The corresponding negative amplification stage is coupled in parallel with the positive amplification stage and is equally weighted as the positive amplification stage, and both the positive amplification stage and the corresponding negative amplification stage selectively contribute to the generation of the amplification output levels for the digitally controlled VGA.

A high-frequency power supply circuit includes an amplifier circuit. In the amplifier circuit, one end of an inductor is connected to a direct-current power supply. One end of a switching element is connected to the other end of the inductor. A parallel capacitor is connected in parallel to the switching element. One end of an LC series circuit is connected to the one end of the switching element. A circuit capacitor is connected between the other end of the LC series circuit and the other end of the switching element. The amplifier circuit amplifies a signal having a unique frequency input to a control terminal of the switching element. The amplifier circuit outputs, to a load, a current having the frequency from a connection point between the other end of the LC series circuit and the circuit capacitor.

This disclosure is directed to reducing output voltage distortions of Variable Gain Amplifiers (VGAs). A VGA may include a number of amplifiers each providing a portion of a total gain of the VGA. For example, a processing circuit may select one or more of the amplifiers of the VGA to provide the output signal with a selected gain. However, the selected amplifiers may provide amplified signals with one or more distortion signals when receiving a bias voltage. Systems and methods are described to reduce or cancel the distortion signals of the selected amplifiers by providing a subthreshold nonzero bias voltage (e.g., a weak voltage) to the remaining (e.g., non-selected) amplifiers of the VGA. For example, the non-selected amplifiers may receive the weak voltage to provide distortion signals with similar voltage amplitude and out of phase compared to the distortion signals of the selected amplifiers.

An apparatus for detecting difference in operating characteristics of a main circuit by using a replica circuit is presented. In one exemplary case, a sensed difference in operating characteristics of the two circuits is used to drive a tuning control loop to minimize the sensed difference. In another exemplary case, several replica circuits of the main circuit are used, where each is isolated from one or more operating variables that affect the operating characteristic of the main circuit. Each replica circuit can be used for sensing a different operating characteristic, or, two replica circuits can be combined to sense a same operating characteristic.

Circuits, devices and methods related to amplification with active gain bypass. In some embodiments, an amplifier can include a first amplification path implemented to amplify a signal, and having a cascode arrangement of a first input transistor and a cascode transistor to provide a first gain for the signal when in a first mode. The amplifier can further include a second amplification path implemented to provide a second gain for the signal while bypassing at least a portion of the first amplification path when in a second mode. The second amplification path can include a cascode arrangement of a second input transistor and the cascode transistor shared with the first amplification path. The amplifier can further include a switch configured to allow routing of the signal through the first amplification path in the first mode or the second amplification path in the second mode.

A transmitter device which transmits a first transmit signal and a second transmit signal having different wireless communication standards. The transmitter device includes a power amplifier that amplifies the first transmit signal in a first transmission mode. A first impedance circuit provides the amplified first transmit signal to a radio frequency output port. A second impedance circuit is connected to the first impedance circuit and provides an additional impedance to the first impedance circuit in the first transmission mode. A first switch provides the second transmit signal to the first impedance circuit in a second transmission mode. A second switch connects the second impedance circuit and a ground in the first transmission mode, and floats the second impedance circuit in the second transmission mode.