Abstract: A power amplification system includes: a first power amplifier; an output switch circuit configured to output a power supply to the first power amplifier; a filter circuit that is to connect to a first path in a switchable manner, the first path providing the power supply from the output switch circuit to the first power amplifier; and a digital predistortion circuit configured to generate distortions in a first input signal of the first power amplifier. When the filter circuit is not connected to the first path, the digital predistortion circuit generates the distortions by using a first mathematical-expression model with the first parameter set. When the filter circuit is connected to the first path, the digital predistortion circuit generates the distortions by using a second mathematical-expression model with the second parameter set. The first and second parameter sets are at least partially different from each other.

Abstract: A power amplification system includes: a first power amplifier configured to amplify a first radio-frequency signal; a second power amplifier configured to amplify a second radio-frequency signal; a switched-capacitor circuit configured to generate multiple discrete voltages based on a regulated voltage supplied from a pre-regulator; an output switch circuit configured to selectively output at least one of the multiple discrete voltages as a first power supply of the first power amplifier; and a digital predistortion circuit configured to predistort the first and second radio-frequency signals. The pre-regulator circuit is configured to convert an input voltage to the regulated voltage. The regulated voltage is provided as a second power supply of the second power amplifier without using the switched-capacitor circuit. The digital predistortion circuit predistorts the first radio-frequency signal by using a first mathematical-expression model for digital predistortion.

Abstract: A power amplification system includes: a power amplifier; an output switch circuit configured to selectively output at least one of three or more discrete voltages as a power supply of the power amplifier; and a digital predistortion circuit configured to generate distortions in an input signal of the power amplifier. In a first mode, the digital predistortion circuit is configured to generate distortions in an input signal of the power amplifier by using a first mathematical-expression model for digital predistortion with a first parameter set. In a second mode with a lower average voltage of the power supply than the first mode, the digital predistortion circuit generates the distortions by using at least a different parameter set from the first parameter set, such as a second mathematical-expression model for digital predistortion with a second parameter set or the first mathematical-expression model with a third parameter set.

Abstract: A power amplification system includes: a power amplifier, a D-ET mode and an APT mode being selectively applied to the power amplifier; tracker circuitry configured to selectively supply at least one of multiple discrete voltages as a power supply of the power amplifier in each of the D-ET mode and the APT mode; and a digital predistortion circuit configured to predistort an input signal of the power amplifier. When the D-ET mode is applied to the power amplifier, the digital predistortion circuit predistorts the input signal by using a first mathematical-expression model for digital predistortion. When the APT mode is applied to the power amplifier, the digital predistortion circuit predistorts the input signal by using a second mathematical-expression model for digital predistortion or does not predistort the input signal.

Abstract: An amplifier circuit is provided for amplifying a radio frequency signal within one frame of a radio frequency signal by using multiple discrete voltages supplied from the tracker circuit. The amplifier circuit includes a power amplifier and an RC series circuit including a resistor and a capacitor that are connected in series between the ground and a voltage supply path between the tracker circuit and the power amplifier.

Abstract: A tracker circuit includes a pre-regulator circuit configured to convert an input voltage into a regulated voltage using a power inductor, a switched-capacitor circuit configured to generate a plurality of discrete voltages, based on the regulated voltage, and a power modulation circuit configured to select at least one voltage from the plurality of discrete voltages and output the at least one voltage to a first output terminal. Further, the tracker circuit includes one or more bypass paths configured to bypass at least the switched-capacitor circuit and the power modulation circuit, and to provide a second supply voltage from the pre-regulator circuit to a second output terminal, the second supply voltage is output by the second output terminal.

Abstract: In an exemplary aspect, a tracker circuit is provided that includes a first switch circuit configured to generate a plurality of discrete voltages, based on an input voltage, a second switch circuit configured to select at least a first voltage from the plurality of discrete voltages as a supply voltage, a filter circuit that is connected to the second switch circuit and is configured to filter the supply voltage and generate a filtered supply voltage that is provided to an amplifier via a voltage supply path between the filter circuit and the amplifier, and a third switch circuit including a capacitor and a switch that are connected in series between a ground and the voltage supply path.

Abstract: A tracker module includes a module laminate configured to provide interconnections to circuit components arranged on the module laminate, at least one integrated circuit arranged on the module laminate, and a first output terminal and a plurality of second output terminals that are configured to output signals externally of the tracker module. The at least one integrated circuit includes a first supply modulator and at least one switch in a switched-capacitor circuit. The switched-capacitor circuit is configured to generate a plurality of discrete voltages, the plurality of discrete voltages being supplied to the plurality of second output terminals to output. The first supply modulator is configured to generate a first power supply by selecting at least one of the plurality of discrete voltages, the first power supply is provided to the first output terminal to output.