A peak detector for a power amplifier is provided that includes a threshold voltage detector configured to pulse a detection current in response to an amplified output signal from the amplifier exceeding a peak threshold. A plurality of such peak detectors may be integrated with a corresponding plurality of power amplifiers in a transmitter. Should any peak detector assert an alarm signal or more than a threshold number of alarm signals during a given period, a controller reduces a gain for the plurality of power amplifiers.

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.

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 radio frequency (RF) amplifier and a bias circuit are provided. The RF amplifier includes an amplifier, a first inductive-capacitive resonance circuit, and a first bias circuit. The amplifier includes an input terminal configured to receive an incoming RF signal through a first RF path. The first inductive-capacitive resonance circuit includes a first terminal coupled to a first reference voltage. A second terminal of the first inductive-capacitive resonance circuit is coupled to the first RF path. In response to the first reference voltage being at a first reference level, the RF amplifier is enabled; in response to the first reference voltage being at a second reference level, the RF amplifier is disabled. The first bias circuit includes a first terminal configured to be coupled to the first reference voltage and a second terminal coupled to the input terminal of the amplifier to provide a first direct current (DC) component.

The, present application provides a filtering circuit and a. TV antenna amplifier, the filtering circuit includes a switching module, and the switching module includes a control unit and at least two filtering units. The present application switchably render one of the at least two filtering units conductive through the control unit, and filter the signals of different frequencies in the input signals through the at least two filtering units, so that different filtering units can be switched according to the filtering requirements of the frequency signal in different regions, which makes it a wide application range.

The present disclosure facilitates impedance matching between a power amplifier and filters. A radio-frequency circuit includes a power amplifier, a plurality of transmit filters, a switch, a plurality of first matching networks, and a second matching network. The switch switches the plurality of transmit filters to be coupled to the power amplifier. The plurality of first matching networks are coupled between the plurality of transmit filters and the switch. The second matching network is coupled between the power amplifier and the switch. The second matching network includes a transmission line transformer.

Apparatus and methods for reconfigurable power amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver configured to generate a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier configured to selectively amplify one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an output capacitance of the pair of amplifiers.

A power amplifier module includes an output-stage amplifier, a driver-stage amplifier, an input switch, an output switch, an input matching circuit, an inter-stage matching circuit, an output matching circuit, and a control circuit. The input switch selectively connects one of a plurality of input signal paths to an input terminal of the driver-stage amplifier. The output switch selectively connects one of a plurality of output signal paths to an output terminal of the output-stage amplifier. The control circuit controls operations of the driver-stage amplifier and the output-stage amplifier. The input switch, the output switch, and the control circuit are integrated into an IC chip. The control circuit is disposed between the input switch and the output switch.

A power amplifier unit includes a power amplifier circuit that amplifies a radio-frequency input signal, a first impedance matching circuit that performs impedance matching for an output signal of the power amplifier circuit, a second-order harmonic termination circuit on an output side of the first impedance matching circuit and that reflects at least part of even-ordered and odd-ordered harmonics contained in a signal input from the first impedance matching circuit to output the at least part of the harmonics from an input terminal as a radio-frequency signal and outputs a radio-frequency signal containing a fundamental and the remainder of the harmonics from an output terminal, and a filter that is on a subsequent stage of the second-order harmonic termination circuit, that attenuates at least part of the even-ordered and odd-ordered harmonics, and that outputs a radio-frequency signal including the fundamental and the remainder of the even-ordered and odd-ordered harmonics.

A semiconductor amplifier 1 includes transistors 21a and 21b mounted side by side on a bottom plate 2 in a space in a package 6, a matching circuit 22a mounted between the transistors 21a, 21b on the bottom plate 2, a matching circuit 22b mounted on an opposite side of the transistor 21b from the transistor 21a on the bottom plate 2, an input terminal T.sub.IN installed on one side of a wiring substrate 3, an output terminal T.sub.OUT installed on the other side of the wiring substrate 3, and gate bias terminals T.sub.1G and T.sub.2G and drain bias terminals T.sub.1D and T.sub.2D installed at positions with the input terminal T.sub.IN and the output terminal T.sub.OUT of the wiring substrate 3, and the transistor 21a, the matching circuit 22a, the transistor 21b, and the matching circuit 22b are linearly placed between the input terminal T.sub.IN and the output terminal T.sub.OUT.