A voltage dividing capacitor circuit includes first capacitor through third capacitor dividers and first through fourth load capacitors. The first capacitor divider includes a first flying capacitor and a plurality of first switches connected in series between a first voltage node and a ground node, and is connected to a second voltage node. The second capacitor divider is connected to the first voltage node, the second voltage node, and a first intermediate voltage node. The third capacitor divider is connected to the second voltage node, the ground voltage node, and a second intermediate voltage node. The first through fourth load capacitors are connected in series between the first voltage node and the ground node. The second capacitor divider includes a second flying capacitor and a plurality of second switches connected in series between the first voltage node and the second voltage node.

An audio system has an amplifier for driving an audio actuator and includes a switched-mode power supply that draws power from a power source (e.g., battery) to supply power to the amplifier, a capacitor charged by the switched-mode power supply to supply power to the amplifier, and a feed-forward compressor that performs dynamic range compression of an audio input to provide an audio output for amplification by the amplifier. The compressor includes a sidechain frequency-biasing filter that generates a frequency-biased version of the audio input that is attenuated as frequency increases which causes the compressor to decrease the compression as frequency increases. A control block limits current drawn from the battery by the switched-mode power supply independent of audio input frequency, but the frequency-biasing filter enables the amplifier to service audio power transients greater than the current-limited power supply can supply by advantageously concurrently sourcing extra power from the capacitor.

A method is provided. The method includes estimating adjacent channel leakage ratios respectively corresponding based on a test output signal output from a power amplifier according to a test input signal corresponding to a plurality of frequencies; selecting a test delay value corresponding to a largest value among the estimated adjacent channel leakage ratios; and providing a supply voltage to the power amplifier based on an envelope signal delayed according to the selected test delay value. For each of the plurality of test delay values, a corresponding adjacent channel leakage ratio is estimated based on a ratio of a magnitude of a component included in the test output signal and a magnitude of an inter-modulated component.

An electronic device may include: at least one communication processor, an RFIC, at least one power amplifier , and at least one converter and wherein the at least one communication processor is configured to: set a driving voltage, to be applied to a first power amplifier for amplifying a first RF signal provided from the RFIC among the at least one power amplifier, to be a first voltage, based on an APT mode, control at least part of the at least one converter to provide a first voltage, set based on the APT mode, to the first power amplifier during a transmission period of the first RF signal, and control at least part of the at least one converter to provide the first voltage to the first power amplifier during at least partial period of a remaining period in which no RF signal is transmitted, based on the occurrence of an event associated with audible noise.

Fast envelope tracking systems are provided herein. In certain embodiments, an envelope tracking system for a power amplifier includes a switching regulator and a differential error amplifier configured to operate in combination with one another to generate a power amplifier supply voltage for the power amplifier based on an envelope of a radio frequency (RF) signal amplified by the power amplifier. The envelope tracking system further includes a differential envelope amplifier configured to amplify a differential envelope signal to generate a single-ended envelope signal that changes in relation to the envelope of the RF signal. Additionally, the differential error amplifier generates an output current operable to adjust a voltage level of the power amplifier supply voltage based on comparing the single-ended envelope signal to a reference signal.

A power supply switch circuit includes a switch circuit including a first switch configured to switch a first power source voltage to a power supply terminal of a power amplifier, and a second switch configured to switch a second power source voltage to the power supply terminal; a switch controller configured to control the switch circuit; and a power supply circuit configured to supply a third power source voltage to the power supply terminal when a first voltage of the power supply terminal is lower than a predetermined second voltage.

An apparatus for providing a supply control signal for a supply unit, the supply unit being configured to provide a variable controlled power supply to the power amplifier. The apparatus includes a determination module configured to determine a deviation of a signal from at least one nominal value; and an adjustment module configured to provide the supply control signal after an adjustment based on the determined deviation.

Voltage ripple reduction in a power management circuit is disclosed. The power management circuit includes a power amplifier circuit configured to amplify a radio frequency (RF) signal based on a modulated voltage and an envelope tracking integrated circuit (ETIC) configured to provide the modulated voltage to the power amplifier circuit via a conductive path. Notably, an output impedance presenting at an input of the power amplifier circuit can interact with a modulated load current in the power amplifier circuit to create a voltage ripple in the modulated voltage to potentially cause an undesirable error in the RF signal. Herein, the ETIC is configured to modify the modulated voltage based on feedback of the voltage ripple in the modulated voltage. As such, it is possible to reduce the output impedance at the input of the power amplifier circuit to thereby reduce the voltage ripple in the modulated voltage.

Reconfigurable output baluns for wideband push-pull amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver that generates a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier that selectively amplifies one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an impedance of the output balun.

The present invention provides an amplifier system including an audio amplifier and a power converter. The audio amplifier is supplied by at least a first supply voltage and a second supply voltage, and the audio amplifier is configured to receive an audio signal to generate an output signal. The power converter includes only one inductor, and is configured to generate the first supply voltage and the second supply voltage according to an input voltage.