A group delay optimization circuit is provided. The group delay optimization circuit receives a first signal (e.g., a voltage signal) and a second signal (e.g., a current signal). Notably, the first signal and the second signal may experience different group delays that can cause the first signal and the second signal to misalign at an amplifier circuit configured to amplify a radio frequency (RF) signal. The group delay optimization circuit is configured to determine a statistical indicator indicative of a group delay offset between the first signal and the second signal. Accordingly, the group delay optimization circuit may minimize the group delay offset by reducing the statistical indicator to below a defined threshold in one or more group delay optimization cycles. As a result, it may be possible to pre-compensate for the group delay offset in the RF signal, thus helping to improve efficiency and linearity of the amplifier circuit.

A supply modulator, a modulated power supply circuit, and associated control method are provided. The modulated power supply circuit includes the supply modulator and a DC-DC voltage converter, and the supply modulator includes a linear amplifier and a switching converter. The linear amplifier generates an AC component of a modulated voltage according to a regulated voltage and an envelope tracking signal. The supply voltage is converted to the regulated voltage by the DC-DC voltage converter, and the regulated voltage is greater than or less than the supply voltage. The switching converter includes a step-down circuit and a path selection circuit. The path selection circuit selects one of the supply voltage and the regulated voltage as a DC input voltage. The step-down circuit converts the DC input voltage to a DC component of the modulated voltage which is less than the DC input voltage.

Biasing circuitry for RF and microwave integrated circuits keeps the quiescent current of a power amplifier integrated circuit constant when operated with a time-varying DC supply voltage. A dynamic gate bias circuit includes an on-chip sense transistor and control circuitry to keep current of the sense transistor substantially constant by varying sense transistor bias voltage to compensate for variation in the time-varying supply voltage signal. The varying bias voltage is then applied to the amplifying transistors of the power amplifier, resulting in their quiescent current being substantially independent of the time-varying supply voltage.

A PA module includes: a multilayer substrate having a ground pattern layer connected to a ground of a power source; amplifier transistors disposed on the multilayer substrate; a bypass capacitor having one end connected to the collector of the amplifier transistor; a first wiring line connecting the emitter of the amplifier transistor and the ground pattern layer to each other; a second wiring line connecting the emitter of the amplifier transistor and the ground pattern layer to each other; a third wiring line connecting the other end of the bypass capacitor and the ground pattern layer to each other; and a fourth wiring line formed between the amplifier transistor and the ground pattern layer and between the bypass capacitor and the ground pattern layer and connecting the first wiring line and the third wiring line to each other.

A pre-distorter that both accurately compensates for the non-linearities of a radio frequency transmit chain, and that imposes as few computation requirements in terms of arithmetic operations, uses a diverse set of real-valued signals that are derived from separate band signals that make up the input signal. The derived real signals are passed through configurable non-linear transformations, which may be adapted during operation, and which may be efficiently implemented using lookup tables. The outputs of the non-linear transformations serve as gain terms for a set of complex signals, which are functions of the input, and which are summed to compute the pre-distorted signal. A small set of the complex signals and derived real signals may be selected for a particular system to match the classes of non-linearities exhibited by the system, thereby providing further computational savings, and reducing complexity of adapting the pre-distortion through adapting of the non-linear transformations.

A circuit includes an amplifier and pre-distortion circuit. The amplifier amplifies a modulated signal. The signal pre-distortion circuit performs a feed-forward pre-distortion of the modulated signal in a signal path in which the amplifier resides. The signal pre-distortion circuit includes: i) an envelope detector configured operative to provide an envelope information describing an envelope of the modulated signal; and ii) a built-in test circuit that determines distortion information describing a distortion in the signal path caused by amplitude variations. The signal pre-distortion circuit performs the feed-forward pre-distortion of the modulated signal on the basis of the distortion information.

A device for controlling spectral regrowth includes a transmission signal processor configured to generate a baseband transmission signal and a controller. The controller is configured to adjust delay of an envelope tracking path that provides a supply voltage to an envelope tracking power amplifier included in a transmission path that generates a radio frequency (RF) transmission signal from the baseband transmission signal. The controller may obtain allocation information of resource blocks included in the RF transmission signal from the transmission signal processor and may determine the delay of the envelope tracking path based on the allocation information.

A power amplifying circuit includes an amplifier that amplifies a radio-frequency signal and a bypass capacitor section connected to a power supply terminal for supplying a power supply voltage to the amplifier. The bypass capacitor section includes a first capacitor, a second capacitor, and a first switch circuit. The first capacitor includes a first end connected to a power supply path, and a second end. The second capacitor includes a first end connected to the second end of the first capacitor and a second end connected to ground. The first switch circuit includes a first terminal connected to the second end of the first capacitor and the first end of the second capacitor, and a second terminal connected to the ground. The first switch circuit switches between connection and non-connection between the second end of the first capacitor and the ground.

A wireless receiving device includes a wake-up receiver, a main receiver and a calibration circuit. The wake-up receiver operates in a monitoring mode or a sleep mode. When operating in the monitoring mode, the wake-up receiver monitors whether a request signal is transmitted by a communication device and issues a wake-up signal after receiving the request signal. The main receiver operates in a sleep mode or a transmission mode. When operating in the sleep mode, the main receiver is woken up and enters the transmission mode to transmit and receive data to and from the communication device when receiving the wake-up signal. The calibration circuit is coupled to the wake-up receiver and the main receiver and configured to receive a calibration signal from the main receiver and calibrate a reception frequency of the wake-up receiver in the background in response to the calibration signal.

Apparatus and methods for bias switching of power amplifiers are provided herein. In certain configurations, a power amplifier system includes a power amplifier that provides amplification to a radio frequency (RF) signal, a power management circuit that controls a voltage level of a supply voltage of the power amplifier, and a bias control circuit that biases the power amplifier. The power management circuit is operable in multiple supply control modes, such as an average power tracking (APT) mode and an envelope tracking (ET) mode. The bias control circuit is configured to switch a bias of the power amplifier based on the supply control mode of the power management circuit.