A package or a chip including a linear amplifier and a power amplifier is provided, wherein the linear amplifier is configured to receive an envelope tracking signal to generate an amplified envelope tracking signal, the power amplifier is supplied by an envelope tracking supply voltage comprising a DC supply voltage and the amplified envelope tracking signal, and the power amplifier is configured to receive an input signal to generate an output signal.

A power supply circuit in a wireless communications system includes an envelope tracking modulator coupled to a first power amplifier circuit and a second power amplifier circuit, so that the power supply circuit supplies power to the first power amplifier circuit and the second power amplifier circuit. When a transmit signal output by a processor is within a first bandwidth range, the power supply circuit supplies power to the first power amplifier circuit, and the first power amplifier circuit amplifies power of the transmit signal. When the transmit signal output by the processor meets a second bandwidth range, the power supply circuit supplies power to the second power amplifier circuit, and the second power amplifier circuit amplifies the transmit signal.

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.

A digital envelop tracker for a power amplifier. The digital envelop tracker includes a supply filter for filtering a supply voltage to a power amplifier, a level selection circuitry configured to determine a level of supply voltage based on an instantaneous power of an input data stream, schedule a series of switching events based on the determined level of supply voltage, and generate a level select signal based on the scheduled series of switching events, and a switch for connecting one of supply voltages to the supply filter based on the level select signal. The level selection circuitry schedules a primary switching event of the switch based on the determined level of supply voltage and secondary switching events of the switch delayed with respect to the primary switching event based on the determined level of supply voltage to generate a filter response of the supply filter with smaller peaking.

A tracking power supply includes a power conversion subsystem and one or more tracking subsystems. The power conversion subsystem is configured to generate N power rails, where N is an integer greater than one. Each tracking subsystem includes a switching network and a controller. The switching network is electrically coupled between each of the N power rails and a tracking power rail of the tracking power supply. The controller is configured to control operation of the switching network according to a tracking signal associated with a load powered by the tracking power supply, such that a voltage at the tracking power rail is one of two or more values, as determined at least partially based on the tracking signal. The controller is further configured to adjust voltage of at least one of the N power rails.

Apparatus and methods for envelope tracking systems with automatic mode selection are provided herein. In certain configurations, a power amplifier system includes a power amplifier configured to provide amplification to a radio frequency signal and to receive power from a power amplifier supply voltage, and an envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing an envelope signal corresponding to an envelope of the radio frequency signal. The envelope tracker further includes a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

A switching audio amplifier and method of operation. The switching audio amplifier comprises a voltage supply selector coupling a power supply input to a first power supply voltage; a switching circuit generating a drive signal for a loudspeaker by modulating the power supply input based on a modulation signal; a pulse generator receiving an audio input signal and outputting the modulation signal based on the audio input signal and the voltage of the power supply input; and a supply voltage monitor. The supply voltage monitor is configured to increase the voltage of the power supply input by causing the voltage supply selector to couple the power supply input to a second power supply voltage responsive to the modulation signal exceeding the first threshold, and the supply voltage monitor preventing the voltage supply selector from reducing the voltage of the power supply input for a first time period.

The present disclosure relates to switching drivers for driving a transducer. A switching driver (202) has supply nodes for receiving supply voltages (VSH, VSL) defining at least one input voltage and an output node (104). A controller (205) controls operation of the first switching driver to generate a drive signal for the transducer at the output node (104), based on an input signal (Sin). A first capacitor (201a) is connected between first and second capacitor nodes (104, 204a) and a second capacitor (201b) is connected between the second capacitor node (204a) and a third capacitor node (204b). A network of switches (203) selectively connects any of the driver output node, the second capacitor node and the third capacitor node to either of a respective pair of said supply nodes, with the first capacitor node connected to the first driver output node.

The present disclosure generally relates to techniques and apparatus for implementing an envelope-tracking power supply for a radio frequency (RF) power amplifier. One aspect includes an amplification system. The amplification system may include a first amplifier configured to generate an amplifier output voltage, a second amplifier having an output coupled to a supply node for the first amplifier, a voltage regulator having an output coupled to a supply node for the second amplifier, and control circuitry configured to control the voltage regulator to generate a supply voltage at the supply node for the second amplifier based on an indication associated with the amplifier output voltage. In some aspects, the control circuitry may be configured to control the voltage regulator through at least providing an updated control setting for the voltage regulator with a periodicity associated with a power control period.

The present disclosure provides a device and a method for adjusting envelope signals for use by an envelope tracking (ET) enabled power amplifier. The device comprises: a controller configured to calculate a difference between a first amplitude of a first envelope signal received at a first time instance and second amplitude of a second envelope signal received at a second time instance; compare the difference with a predetermined threshold; and adjust an output envelope signal corresponding to the first envelope signal in response to determining that the difference is greater than or equal to the predetermined threshold, such that the output envelope signal is adjusted step-by-step from the second envelope signal to the first envelope signal with each amplitude step being less than or equal to a predetermined amplitude step.