A supply voltage circuit for reducing in-rush battery current in an envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC includes an ET voltage circuit configured to generate a time-variant ET voltage, which includes an offset voltage, in multiple time intervals based on a supply voltage. In some cases, the offset voltage and the supply voltage may both need to be increased or decreased as the time-variant ET voltage increases or decreases. As the offset voltage and the supply voltage increase or decrease, an excessive in-rush battery current may result in a reduced battery life. In this regard, a supply voltage circuit is configured to help the ETIC to adapt the supply voltage on a per-symbol basis. As a result, it is possible to reduce the in-rush battery current in the ETIC while still allowing the time-variant ET voltage to change in a timely manner.

A system for adjusting various parameters of an active electronic component based on sensed characteristics of the active electronic component and/or characteristics of the input or output power.

Target voltage generation in an envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate a time-variant ET voltage based on a time-variant target voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate the time-variant target voltage based on a sensed signal having a time-variant sensed envelope that tracks a time-variant power envelope of the RF signal. Since the time-variant target voltage is generated to track the time-variant sensed envelope, which further tracks the time-variant power envelope, the time-variant ET voltage can better track the time-variant power envelope of the RF signal when the time-variant ET voltage is provided to a power amplifier(s) that amplifies the RF signal.

An envelope tracking (ET) integrated circuit (ETIC) for reducing in-rush battery current is provided. The ETIC includes an ET voltage circuit configured to generate a time-variant ET voltage, which includes an offset voltage, in multiple time intervals based on a supply voltage. In some cases, the offset voltage and the supply voltage may both need to be increased or decreased as the time-variant ET voltage increases or decreases. As the offset voltage and the supply voltage increase or decrease, an excessive in-rush battery current may be generated in the ETIC to result in a reduced battery life. Hence, the ETIC is configured to avoid increasing or decreasing the offset voltage and the supply voltage in a same one of the time intervals. As a result, it is possible to reduce the in-rush battery current in the ETIC while still allowing the time-variant ET voltage to change in a timely manner.

An envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate an ET voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate an ET target voltage based on a power envelope of the RF signal and to generate the ET voltage based on the ET target voltage. Given that the RF signal may be modulated at a very high modulation bandwidth, the ETIC can be configured to modify the ET target voltage in each of the time intervals to thereby cause the ET voltage to be adapted on a per time interval basis. As a result, the ET voltage can better track the power envelope of the RF signal in each of the time intervals to help improve operating efficiency of a power amplifier apparatus that employs the ETIC.

A power management circuit operable with group delay is provided. The power management circuit includes a transceiver circuit configured to generate a digital target voltage and digitally delay the digital target voltage to generate multiple delayed digital target voltages. Accordingly, the transceiver circuit can generate a windowed digital target voltage in multiple delay tolerance windows based on the delayed digital target voltages. Since the windowed digital target voltage can tolerate a certain amount of group delay in each of the group delay tolerance windows, an envelope tracking (ET) voltage generated based on an analog version of the windowed digital target voltage can therefore tolerate the group delay in each of the group delay tolerance windows as well. As a result, it is possible to avoid distortion in the ET voltage to help improve performance of the power management circuit.

Apparatus and methods for power amplifiers with positive envelope feedback are provided herein. In certain implementations, a power amplifier system includes a power amplification stage that amplifies a radio frequency signal, at least one envelope detector that generates one or more detection signals indicating an output signal envelope of the power amplification stage, and a wideband feedback circuit that provides positive envelope feedback to a bias of the power amplification stage based on the one or more detection signals. The power amplifier system further includes a supply modulator that controls a voltage level of a supply voltage of the power amplification stage based on the one or more detection signals such that the supply voltage is modulated with the output signal envelope through positive envelope feedback.

In some embodiments, radio-frequency amplifiers can include a plurality of narrow band power amplifiers implemented. Each narrow band power amplifier can be configured to operate with a high voltage in an average power tracking mode and be capable of being coupled to an output filter associated with a respective individual frequency band. Each narrow band power amplifier can be sized smaller than a wide band power amplifier configured to operate with more than one of the frequency bands associated with the plurality of narrow band power amplifiers.

Systems, circuitries, and methods for predistorting a digital signal in a transmit chain based on a predistortion function are provided. A method includes shifting a center frequency of an input signal by an offset to generate an adapted signal; predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal; reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal; and causing transmission of the predistorted signal by a transmit chain.

A radio-frequency circuit is provided that includes a power amplifier, a control circuit, an on-off switch, a connection terminal, and a mount board. The power amplifier supports an APT system and an ET system. The control circuit controls the power amplifier by using the APT system and the ET system. The on-off switch is connected in series to a capacitive element connected between a path and the ground. The connection terminal is connected to the capacitive element. Moreover, the control circuit overlies the connection terminal in plan view in the thickness direction of the mount board.