A load-insensitive power amplifier power detector that excludes the use of couplers is disclosed. The load-insensitive power amplifier power detector may include a voltage sampling circuit in electrical communication with a collector of a power amplifier and configured to sample a first voltage from the power amplifier. The load-insensitive power amplifier power detector may include a current sampling circuit in electrical communication with the collector of the power amplifier and configured to sample an output current from the power amplifier. Further, the load-insensitive power amplifier power detector may include a current-to-voltage converter connected between the voltage sampling circuit and an output of the load-insensitive power amplifier power detector. The current-to-voltage converter may be configured to convert the output current to obtain a second voltage. Moreover, a combination of the first voltage and the second voltage may form a detector voltage corresponding to an incident power of the power amplifier.

A control system is configured to control an output power of a power amplifier. The control system is operable to detect when the power amplifier is in first state and responsively provide first additional bias to the power amplifier. The first additional bias assists or enables the power amplifier in increasing the output power. The control system is also operable to detect when the power amplifier is in a second state and responsively provide second additional bias to the power amplifier. The second additional bias assists or enables the power amplifier in increasing the amount of output power.

Embodiments of the present application provide a method for predicting envelope features. The method includes: according to baseband data or data after modulation mapping, a peak value of a radio frequency envelope signal, a time point corresponding to the peak value, a valley point of the radio frequency envelope signal and a time point corresponding to the valley point are predicted; according to the valley point and the time point corresponding thereto, a generated reference value is sent to a low-bandwidth control signal generating module to obtain a control signal; according to adjacent valley point and peak point, and time points corresponding thereto, generated status information is sent to a high-bandwidth control signal generating module to obtain a control switch signal; and when in an ascending status, according to a key information string, a slope k of a connecting line is determined, and a corresponding filter inductor is turned on.

Apparatus and methods for power amplifier envelope tracking systems with automatic control of a slew rate and a mode of an error amplifier of the envelope tracking system. The envelope tracker can include a signal bandwidth detection circuit that processes the envelope signal to generate a detected bandwidth signal, and a control circuit that controls the slew rate of the error amplifier based on the detected signal bandwidth.

Apparatus and methods for power amplifier envelope tracking systems with automatic control of a slew rate and a mode of an error amplifier of the envelope tracking system. The envelope tracker can include a signal bandwidth detection circuit that processes the envelope signal to generate a detected bandwidth signal, and a control circuit that controls the slew rate of the error amplifier based on the detected signal bandwidth.

A power amplifier with a quasi-static drain voltage adjustment is provided that has a transistor that is made from Gallium Nitride (GaN). In an exemplary aspect, the transistor is a field-effect transistor (FET) having a source, gate, and drain. The transistor is tested for process variations. Based on detected process variations, a microcontroller may raise a drain voltage to increase output power capability. Power capability of the power amplifier scales as the square of the drain voltage, so small adjustments are sufficient to offset the slow process corner while maintaining reliability

Average power tracking (APT) systems with fast transient settling are disclosed. In certain embodiments, an APT system is used to provide a power amplifier supply voltage to a power amplifier that amplifies a radio frequency (RF) signal. The APT system controls the power amplifier supply voltage to track an average power of the RF signal, and generates a first regulated voltage based on a first average power tracking voltage level and a second regulated voltage based on a second average power tracking voltage level. The APT system includes a DC switch configured to receive the first regulated voltage and the second regulated voltage, and operable to change state to transition the power amplifier supply voltage from the first average power tracking voltage level to the second average power tracking voltage level.

Average power tracking (APT) systems with fast transient settling are disclosed. In certain embodiments, an APT system is used to provide a power amplifier supply voltage to a power amplifier that amplifies a radio frequency (RF) signal. The APT system controls the power amplifier supply voltage to track an average power of the RF signal, and includes a DC-to-DC converter that is assisted by an error amplifier in transitioning from one power amplifier supply voltage level to another power amplifier supply voltage level. Thus, the combination of a DC-to-DC converter with a fast changing error amplifier can swing enough AC voltage with a low enough slew rate to be able to rapidly transition the power amplifier supply voltage from one APT voltage level to another APT voltage level.

One embodiment provides a system comprising a single DC voltage source and a Class-D amplifier comprising at least one DC/DC converter operated by the single DC voltage source. The amplifier is configured to receive an input signal for power amplification, and generate, via the at least one DC/DC converter, a DC output voltage that approaches or exceeds a DC supply voltage from the single DC voltage source. A gain of the amplifier is a ratio of the output voltage level to the input signal. A steady-state operating point of the at least one DC/DC converter is zero output.

Power amplifier modules with controllable envelope tracking noise filters are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier module and an envelope tracker that provides the power amplifier module with a power amplifier supply voltage that changes based on an envelope of a radio frequency (RF) signal amplified by the power amplifier module. The power amplifier module includes a controllable filter that filters the power amplifier supply voltage to provide flexibility in filtering envelope tracking noise.