An amplitude modulation-phase modulation compensation circuit includes a detection circuit, a reconfigurable current control voltage source circuit and a phase shifting circuit, in which, the detection circuit is configured to detect the power of an input signal and output a control current according to the power of the input signal when the power of the input signal is greater than a preset power threshold; the reconfigurable current control voltage source circuit is configured to generate a bias voltage according to the control current; the phase shifting circuit is configured to compensate the AM-PM distortion of the radio frequency power amplifier according to the bias voltage. In this way, by the compensation circuit, when the power of the input signal is greater than a preset power threshold, the AM-PM distortion of the radio frequency power amplifier can be compensated according to the power of the input signal.

A system and method for digital correction for a dynamically varying non-linear system. The system includes a correction circuitry including at least one look-up table (LUT). The correction circuitry is configured to receive an input signal and modify the input signal to be processed by the non-linear system using at least one LUT to correct non-linearity incurred by the non-linear system. The at least one LUT is addressed by a magnitude or power of the input signal and a dynamically varying parameter associated with the input signal. The dynamically varying parameter may be one of average signal power of the input signal, a differential of the average power of the input signal, a directional beam index, or temperature.

A power amplifier circuit including a plurality of analog power amplifiers configured to generate a output power for an output signal; at least one processor configured to: select a highest output power signal; determine an input signal power of a modulated signal; determine an output signal power based on the input signal power; compare the output signal power and the highest output power; and disable a subset of the plurality of analog power amplifiers based on the comparison, wherein a remainder of the plurality of analog power amplifiers are configured to generate the output signal power.

A power amplifier circuit including a plurality of analog power amplifiers configured to generate a output power for an output signal; at least one processor configured to: select a highest output power signal; determine an input signal power of a modulated signal; determine an output signal power based on the input signal power; compare the output signal power and the highest output power; and disable a subset of the plurality of analog power amplifiers based on the comparison, wherein a remainder of the plurality of analog power amplifiers are configured to generate the output signal power.

This application relates to method and apparatus for driving acoustic transducers, such as speakers or haptic transducers. A transducer driver circuit (200) has a hysteretic comparator (201) configured to compare, with hysteresis, an input signal (S.sub.IN) received at a first comparator input to a feedback signal (S.sub.FB) received at a second comparator input. Based on the comparison the hysteretic comparator (201) generates a pulse-width modulation (PWM) signal (S.sub.PWM) at a comparator output (206). An inductor (203) is coupled between the comparator output and an output node (204). In use a resistive component (208), which may comprise the transducer (301) is coupled to output node (204). The inductor (203) and resistive component (208) provide filtering to the PWM signal (S.sub.PWM). A feedback path extends between the output node (204) and the second comparator input to provide the feedback signal (S.sub.FB).

This application relates to method and apparatus for driving acoustic transducers, such as speakers or haptic transducers. A transducer driver circuit (200) has a hysteretic comparator (201) configured to compare, with hysteresis, an input signal (S.sub.IN) received at a first comparator input to a feedback signal (S.sub.FB) received at a second comparator input. Based on the comparison the hysteretic comparator (201) generates a pulse-width modulation (PWM) signal (S.sub.PWM) at a comparator output (206). An inductor (203) is coupled between the comparator output and an output node (204). In use a resistive component (208), which may comprise the transducer (301) is coupled to output node (204). The inductor (203) and resistive component (208) provide filtering to the PWM signal (S.sub.PWM). A feedback path extends between the output node (204) and the second comparator input to provide the feedback signal (S.sub.FB).

A harmonic processing circuit includes a first inductor having a first end connected to a connection line connected between an amplifier and an impedance matching circuit, and a second end connected to a first node, a first transmission line having a third end connected to the first node and a fourth end connected to a second node, and a parallel resonant circuit having a fifth end connected to the second node and a sixth end connected to a reference potential, wherein a second inductor and a first capacitor are connected in parallel between the fifth end and the sixth end, wherein when the first inductor is viewed from the connection line, an impedance at a frequency of a fundamental wave amplified by the amplifier is larger than an impedance at a frequency of a second harmonic having twice the frequency of the fundamental wave.

A harmonic processing circuit includes a first inductor having a first end connected to a connection line connected between an amplifier and an impedance matching circuit, and a second end connected to a first node, a first transmission line having a third end connected to the first node and a fourth end connected to a second node, and a parallel resonant circuit having a fifth end connected to the second node and a sixth end connected to a reference potential, wherein a second inductor and a first capacitor are connected in parallel between the fifth end and the sixth end, wherein when the first inductor is viewed from the connection line, an impedance at a frequency of a fundamental wave amplified by the amplifier is larger than an impedance at a frequency of a second harmonic having twice the frequency of the fundamental wave.

A circuit includes a main amplifier having a first input and a first output. A main bias circuit is coupled to the main amplifier, and the main bias circuit configured to operate the main amplifier in a first frequency band. A feedforward cancellation amplifier has a second input and a second output, in which the second input is coupled to the first input, and the second output is coupled to the first output. A filter is coupled between the first input and the second input. A feedforward bias circuit is coupled to the feedforward cancellation amplifier. The feedforward bias circuit is configured to operate the feedforward cancellation amplifier in a second frequency band within and narrower than the first frequency band.

Envelope tracking (ET) voltage correction in a transmission circuit is provided. The transmission circuit includes a transceiver circuit and a power amplifier circuit(s). The transceiver circuit generates a radio frequency (RF) signal(s) from a time-variant modulation vector and the power amplifier circuit(s) amplifies the RF signal(s) based on a modulated voltage and provides the amplified RF signal(s) to a coupled RF front-end circuit. Herein, the transceiver circuit is configured to apply an equalization filter to a selected form of the time-variant modulation vector to compensate for a voltage distortion filter created across a modulation bandwidth of the RF signal(s) by coupling the power amplifier circuit with the RF front-end circuit. As a result, it is possible to reduce undesired instantaneous excessive compression and/or spectrum regrowth resulting from the voltage distortion filter to thereby improve efficiency and linearity of the power amplifier circuit(s) across the modulation bandwidth of the RF signal(s).