A high frequency amplification circuit includes transmission amplification circuits 11 and 12; a transmission filter D-Tx whose pass band is a band D of a first frequency band group; transmission filters E-Tx and G-Tx whose pass bands are respectively bands E and G of a second frequency band group; an output matching circuit 31 configured to match the transmission amplification circuit 11 and the transmission filter D-Tx; and an output matching circuit 32 configured to match the transmission amplification circuit 12 and the transmission filters E-Tx and G-Tx. The band D is positioned at a high frequency-side end portion of the first frequency band group, and the band E is positioned at a low frequency-side end portion of the second frequency band group. The output matching circuit 31 includes a low-pass circuit, and the output matching circuit 32 includes an impedance-variable circuit.

A high frequency amplification circuit includes transmission amplification circuits 11 and 12; a transmission filter D-Tx whose pass band is a band D of a first frequency band group; transmission filters E-Tx and G-Tx whose pass bands are respectively bands E and G of a second frequency band group; an output matching circuit 31 configured to match the transmission amplification circuit 11 and the transmission filter D-Tx; and an output matching circuit 32 configured to match the transmission amplification circuit 12 and the transmission filters E-Tx and G-Tx. The band D is positioned at a high frequency-side end portion of the first frequency band group, and the band E is positioned at a low frequency-side end portion of the second frequency band group. The output matching circuit 31 includes a low-pass circuit, and the output matching circuit 32 includes an impedance-variable circuit.

A plurality of transmission lines (3b,3c) are connected to a transistor (1) and have different characteristic impedances. A plurality of open stubs (4a,4b) are connected to the plurality of transmission lines (3b,3c) respectively. A length of each open stub (4a,4b) is shorter than a length of each transmission line (3b,3c).

Circuits, devices, and methods for operating a charge pump. In some implementations, a charge pump module includes a clock circuit configured generate to a first clock signal and a second clock signal, the first clock signal having a lower frequency than the second clock signal. The charge pump module also includes a driving circuit configured to generate a first set of clock signals based on the first clock signal and a second set of clock signals based on the second clock signal, the driving circuit coupled to the clock circuit. The charge pump module further includes a charge pump core including a set of capacitances, the charge pump core configured to charge the set of capacitances based the first set of clock signals and the second set of clock signals.

A current compensation circuit for providing a current to an amplifier circuit includes a first amplifier, a first transistor and a first bias circuit. The first bias circuit provides a first bias current to the first amplifier. The current compensation circuit includes a power detection circuit, an operational amplifier circuit and a current-to-voltage converter. The power detection circuit detects and converts an input power or an output power of the first amplifier to a first detection voltage. The operational amplifier circuit generates a second detection voltage according to the first detection voltage and a calibration voltage. The current-to-voltage converter converts the second detection voltage to a compensation current. A first compensation current flows to the first amplifier through the first transistor according to the compensation current, such that the first amplifier is driven by the first bias current plus the first compensation current.

A current compensation circuit for providing a current to an amplifier circuit includes a first amplifier, a first transistor and a first bias circuit. The first bias circuit provides a first bias current to the first amplifier. The current compensation circuit includes a power detection circuit, an operational amplifier circuit and a current-to-voltage converter. The power detection circuit detects and converts an input power or an output power of the first amplifier to a first detection voltage. The operational amplifier circuit generates a second detection voltage according to the first detection voltage and a calibration voltage. The current-to-voltage converter converts the second detection voltage to a compensation current. A first compensation current flows to the first amplifier through the first transistor according to the compensation current, such that the first amplifier is driven by the first bias current plus the first compensation current.

A variable gain amplifier circuit including a first amplifier, a second amplifier, and a variable capacitor connected in series between the first amplifier and the second amplifier is disclosed. As a gain of the variable gain amplifier circuit varies, the input impedance, output impedance, noise figure and third-order output intercept point (OIP3) of the variable gain amplifier circuit remain unchanged.

Methods and devices for improving AM-AM and AM-PM performance of an RF amplifier are presented. According to one aspect, input and output harmonic terminations coupled to the input and output of the amplifier are tuned at frequencies near to, but different than, a second harmonic frequency of an RF signal to be amplified. Improved AM-AM and AM-PM performance is obtained when i) the input harmonic termination is tuned at a frequency that is below the second harmonic frequency and the output harmonic termination is tuned at a frequency that is above the second harmonic frequency, and ii) the input harmonic termination is tuned at a frequency that is farther away from the second harmonic frequency than the frequency used for tuning of the output harmonic termination.

Aspects of this disclosure relate to compensating for dynamic error vector magnitude. A compensation circuit can generate a compensation signal based at least partly on an amount of time that an amplifier, such as a power amplifier, is turned off between successive transmission bursts of the amplifier. For example, the compensation circuit can charge a capacitor based at least partly on an amount of time that the amplifier is turned off between successive transmission bursts and generate the compensation signal based at least partly on an amount of charge stored on the capacitor. A bias circuit can receive the compensation signal, generate a bias signal based at least partly on the compensation signal, and provide the bias signal to the amplifier to bias the amplifier.

Aspects of this disclosure relate to compensating for dynamic error vector magnitude. A compensation circuit can generate a compensation signal based at least partly on an amount of time that an amplifier, such as a power amplifier, is turned off between successive transmission bursts of the amplifier. For example, the compensation circuit can charge a capacitor based at least partly on an amount of time that the amplifier is turned off between successive transmission bursts and generate the compensation signal based at least partly on an amount of charge stored on the capacitor. A bias circuit can receive the compensation signal, generate a bias signal based at least partly on the compensation signal, and provide the bias signal to the amplifier to bias the amplifier.