A power amplifier system having a power amplifier stage with dynamic bias circuitry is disclosed. Also included is bias control circuitry having a compression sensor having a sensor input coupled to a RF signal output and a sensor output, wherein the compression sensor is configured to generate a gain deviation signal in response to a sensed deviation from a flat gain profile of the power amplifier stage. Further included is a bias driver that is configured to drive dynamic bias circuitry to adjust bias to the power amplifier stage to maintain the flat gain profile in response to the gain deviation signal.

A switching system is connected to the power amplifier of an RF system. The switching system can switch the DC supply voltage to the power amplifier while handling the high DC current and the nanosecond switching speed requirements that are mandatory for most RF systems. The embodiments can rapidly control DC voltages but not interfere with the optimized operation of the RF transistor. The embodiments provide a desired sharp turn-on leading edge for an RF pulse while eliminating the extremely long and undesirable ramp down that typically occurs beyond the desired RF pulse period.

A method and apparatus is provided. The method includes determining a training data set comprising input and output data of a power amplifier, determining compensation data by regressing the training data using a frequency domain weighting function, storing the compensation data, and linearizing an output of the power amplifier using the stored compensation data.

Various embodiments of the present invention relate to a power amplification device and method, wherein the power amplification device can comprise: a power amplifier; a switch mode converter for controlling a bias of the power amplifier; a comparator for providing a switching signal to the switch mode converter according to an envelope signal; and a control unit for determining whether a switching frequency of the switch mode converter is within a specific band and applying an offset to the switching frequency so as to deviate from the specific band if the switching frequency of the switch mode converter is within the specific band. Various other embodiments can be carried out.

17 ABSTRACT A transmitter and Doherty power amplifier configured for envelope-controlled biasing of an auxiliary transmitter of the Doherty power amplifier are disclosed. According to one aspect, a transmitter having a main amplifier in a main signal path and an auxiliary amplifier in an auxiliary signal path is provided. The auxiliary amplifier is configured to be activated only when an envelope of an input signal of the transmitter exceeds a power threshold. The transmitter also includes at least one component in the auxiliary signal path configured to be deactivated when the auxiliary amplifier is deactivated, the at least one component including at least one of a pre-power amplifier, a mixer and a local oscillator buffer.

The present invention relates to a method, of providing adaptive impedance in a Power Amplifier (PA), by providing more than one transistors in which one transistor is used to change the load line or to linearize the input signal by adapting the biasing of each transistor, wherein the transistors are connected in parallel.

An audio amplifier circuit for providing an output signal to an audio transducer may include a power amplifier and a control circuit. The power amplifier may include an audio input for receiving an audio input signal, an audio output for generating the output signal based on the audio input signal, and a power supply input for receiving a power supply voltage, wherein the power supply voltage is variable among at least a first supply voltage and a second supply voltage greater than the first supply voltage. The control circuit may be configured to predict, based on one or more characteristics of a signal indicative of the output signal, an occurrence of a condition for changing the power supply voltage, and responsive to predicting the occurrence of the condition, change, at an approximate zero crossing of the signal indicative of the output signal, the power supply voltage.

application relates to an amplifier selectively operable in first or second modes. The first mode is a BTL mode with first and second output drivers (103p, 103n) both active to generate respective driving signals that vary with an input signal. The second mode is an SE mode, where the first output driver (103p) is active to generate a driving signal at and the output of the second driver (103n) is held constant. A controller (201) selectively controls the mode based on an indication of output signal amplitude. In the first mode, a ratio of magnitude of the two driving signals varies with the indication of output signal amplitude, i.e. the magnitudes of the two driving signals may vary so as to be not equal.

Methods and apparatus for detection and tracking of a signal envelope. The circuit comprises absolute value circuitry configured to receive data samples and output a first value corresponding to the magnitude of said data samples. An envelope tracker maintains an envelope output value and compares the first value to the current envelope output value and modifies the envelope output value based on said comparison to provide the envelope output value with predetermined attack and decay characteristics. The absolute value circuitry has a first input for receiving a first digital signal at a first sample rate and a second input for receiving an interpolated version of the first digital signal at a second sample rate which is higher than the first sample rate and outputs the first value based on the magnitudes of the samples received at the first input and the samples received at the second input. Using the first digital signal provides an early indication of any increases in signal envelope whereas the second digital signal can allow a more accurate estimation.

Systems and methods implementing dithered hysteretic current control are discussed. One system can include a switched-mode power supply, a control component, and a dither component. The control component can detect a crossing of a first threshold associated with a first mode of the switched-mode power supply, and generate first and second control signals, wherein the first control signal is based on the crossing of the first threshold. The dither component can receive the first control signal, delay the first control signal for a first random time period, and output the first control signal to the switched-mode power supply. The switched-mode power supply can receive the first control signal and the second control signal, switch from the first mode to a second mode based on the first control signal, and switch from the second mode to the first mode based on the second control signal.