A tracker circuit configured to provide a variable supply voltage to a power amplifier (PA) circuit is disclosed. The tracker circuit comprises a predefined state machine circuit comprising a plurality of states mapped in accordance with transitions associated with a predefined mapping scheme. In some embodiments, the plurality of states of the state machine circuit identify one or more operational modes associated with the tracker circuit, wherein the one or more operational modes comprises one or more voltage levels respectively associated therewith. In some embodiments, the one or more operational modes comprises at least two active operational modes. In some embodiments, a transition between the one or more operational modes of the tracker circuit is dictated by a decoding of a digital selection signal received from a digital communication interface associated therewith.

Amplifiers for radio-frequency applications. In some embodiments, a power amplifier die can include a semiconductor substrate and a plurality of narrow band power amplifiers implemented on the semiconductor substrate. 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.

A system includes an input port having an input voltage, an output port having an output voltage, and a power converter having a switch network with a plurality of power switches and a first resonant tank having a first resonant capacitor and a first resonant inductor, where at least one resonant component within the first resonant capacitor and the first resonant inductor is a switchable component configured to switch between different values. The system further includes a resonant mode selection block configured to adjust a value of the switchable component to maintain a performance of the system, and a controller configured to adjust a switching frequency or a duty cycle of the power converter.

Power amplification units and methods are provided, which use a combiner and an auxiliary signal to feed the power amplifier (PA) with a signal that prevents or reduces operation of higher amplification stages during off periods of the received RF signal. The PA output is delivered through an output matching circuit configured to pass the RF signal and attenuate the auxiliary signal; and the combiner combines the RF signal and the auxiliary signal through respective filters to generate the RF input signal to the PA. An auxiliary signal generator may be configured to generate the auxiliary signal with relation to the RF signal as having a frequency spectrum lower than a cutoff RF frequency. Resulting lower power consumption, particularly in case of low duty cycle RF signals, reduces heating, enables longer battery use and increases reliability performance.

A supply modulator, a modulated power supply circuit, and associated control method are provided. The modulated power supply circuit includes the supply modulator and a DC-DC voltage converter, and the supply modulator includes a linear amplifier and a switching converter. The linear amplifier generates an AC component of a modulated voltage according to a regulated voltage and an envelope tracking signal. The supply voltage is converted to the regulated voltage by the DC-DC voltage converter, and the regulated voltage is greater than or less than the supply voltage. The switching converter includes a step-down circuit and a path selection circuit. The path selection circuit selects one of the supply voltage and the regulated voltage as a DC input voltage. The step-down circuit converts the DC input voltage to a DC component of the modulated voltage which is less than the DC input voltage.

A method and operates for generating a boost control signal for a DC-DC-booster is described. An audio signal may be received comprising a plurality of audio sample values. The audio signal may be delayed for a delay time. A maximum-delayed-value of the audio sample values during the delay time may be determined. The boost control signal may be generated from the maximum of the non-delayed audio signal sample value and the maximum-delayed-value.

A variable load power amplifier that improves the performance of a power amplifier that provides both envelope tracking (ET) and average power tracking (APT). The variable load power amplifier can include a plurality of amplifiers that are each selectively connectable into one of a plurality of parallel combinations, each of the plurality of parallel combinations characterized by a corresponding load line. The variable load power amplifier can also include a plurality of control elements arranged to selectively connect one or more of the plurality of amplifiers into one of the plurality of parallel combinations, each of the plurality of control elements having a respective input terminal provided to receive a respective control signal, each of the plurality of control elements responsive to the respective control signal.

Systems, methods and apparatus for efficient power control and/or compensation with respect to a varying supply voltage of an RF amplifier for amplification of a constant envelope RF signal are described. A reduction in a size of a pass device of an LDO regulator is obtained by removing the pass device of the LDO regulator from a main current conduction path of the RF amplifier. Power control and/or compensation is provided by varying one or more gate voltages to cascoded transistors of a transistor stack of the RF amplifier according to a power control voltage. Various configurations for controlling the gate voltages are presented by way of a smaller size LDO regulator or by completely removing the LDO regulator. In a case where a supply voltage to the transistor stack varies, such as in a case of a battery, a compensation circuit is used to adjust the power control voltage in view of a variation of the supply voltage, and therefore null a corresponding drift/variation in output power of the RF amplifier.

According to certain embodiments, a method of operating an electronic device includes identifying an RSSI value and setting a power amplifier to a first power amplification mode or a second power amplification mode based on the identified one or more RSSI value, wherein the first power amplification mode and the second power amplification mode supply different supply voltages to the power amplifier.

An envelope tracking (ET) bias circuit includes a detection circuit configured to select an ET operation voltage input through a first input terminal of the detection circuit, or an envelope signal detected from a radio frequency (RF) signal input through a second input terminal of the detection circuit, in response to a first control signal, to and output he selected one of the ET operation voltage and the envelope signal as a detection signal; an amplification circuit configured to amplify the detection signal, and output the amplified detection signal; and a bias output circuit configured to generate an ET bias current based on the amplified signal, and output the generated ET bias current.