Provided is a microphone system insensitive to external noise, and the microphone system includes a microphone sensor that generates sensing data by sensing a change in sound pressure through a sensor bias voltage, a lead-out circuit that provides the sensor bias voltage for operating the microphone sensor, removes noise of the sensing data, and outputs the sensing data, a first pad that connects the microphone sensor and the lead-out circuit to each other and allows the sensor bias voltage to pass therethrough, and a second pad that connects the microphone sensor and the lead-out circuit to each other and allows the sensing data to pass therethrough.

Systems and methods for driving using a radio-frequency integrated circuit to drive one or more front end modules. The front end modules provide signal flexibility to an electronic device. The radio-frequency integrated circuit drives the one or more front end modules via dual-pole, dual-throw switches that enable a pair of radio-frequency chains in the radio-frequency integrated circuit to drive two pairs of radio-frequency chains in each of two connected front end modules.

A multistage Doherty power amplifier and a transmitter are provided, and the multistage Doherty power amplifier includes: a generalized carrier amplifier, which is a nested 2-way inverted Doherty sub amplifier, and a generalized peaking amplifier, connected to the generalized carrier amplifier, which is a nested single ended sub amplifier or a nested 2-way normal Doherty sub amplifier, the generalized carrier amplifier and the generalized peaking amplifier are arranged in a generalized 2-way inverted Doherty power amplifier form. With the multistage Doherty power amplifier, signal power probability distribution function (PDF) oriented for a cost-effective multi stage Doherty PA design is applied, and 2-way normal and inverted Doherty PA cells are used as basic units to construct multistage Doherty PA with gain extension effect.

A transformer-based Doherty power amplifier includes a main power amplifier path and an auxiliary power amplifier path which are connected in parallel. The main power amplifier path includes a main power amplifier, and the auxiliary power amplifier path includes an auxiliary power amplifier. The transformer-based Doherty power amplifier further includes a first linear network circuit or a second linear network circuit. The first linear network circuit is arranged at an input of the main power amplifier and is used to compensate for variations of an input capacitance of the main power amplifier, so as to improve the linearity of the main power amplifier. The second linear network circuit is arranged at an input of the auxiliary power amplifier and is used to compensate for variations of an input capacitance of the auxiliary power amplifier, so as to improve the linearity of the auxiliary power amplifier.

Techniques are described for power detection of an amplified signal. For example, power detection described herein can receive an amplified signal from a power amplifier, and can generate an output signal that can be fed back to help regulate an output level of the power amplifier. Embodiments receive the amplified signal can be received by a transistor. A first measurement can be obtained at the transistor's emitter corresponding to an average bias level of the amplified signal, and a second measurement can be obtained at the transistor's base. The output signal can be generated as a function of a difference between the two measurements. Some embodiments further compensate for a measured effective diode voltage corresponding to a base-emitter voltage. Such an approach can generate the power detector output signal to be independent of the of the transistor, and therefore less affected by variations in process corners and temperature.

A high-frequency front-end circuit includes a plurality of power amplifiers. Power supply inductors and matching inductors for the power amplifiers are formed of conductors disposed on a substrate. The power supply inductors and the matching inductors are disposed on or in different layers. When the substrate is seen in a plan view, at least a portion of the first power supply inductor and at least a portion of the second matching inductor overlap each other with an insulating layer interposed therebetween.

A gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

A scalable periphery tunable matching power amplifier is presented. Varying power levels can be accommodated by selectively activating or deactivating unit cells of which the scalable periphery tunable matching power amplifier is comprised. Tunable matching allows individual unit cells to see a constant output impedance, reducing need for transforming a low impedance up to a system impedance and attendant power loss. The scalable periphery tunable matching power amplifier can also be tuned for different operating conditions such as different frequencies of operation or different modes.

Doherty power amplifier having high supply voltage. In some embodiments, a power amplification system can include a supply system configured to provide a high-voltage supply signal, and a Doherty power amplifier having an input splitter configured to receive and split a signal into a carrier amplifier and a peaking amplifier. The Doherty power amplifier can further include a combiner configured to combine amplified signals from the carrier and peaking amplifiers to provide an output signal. The Doherty power amplifier can be configured to receive the high-voltage supply signal for operation of the carrier and peaking amplifiers. The power amplification system can further include an output path configured to couple the combiner to a filter. The Doherty power amplifier can have an impedance substantially the same as an impedance of the filter when operated with the high-voltage supply signal.

An amplifier circuit for a parametric transducer, comprising: a signal processor for processing an input signal into first and second signals; and at least a pair of output stages arranged to respectively receive the first and second signals for generating amplified first and second signals respectively, which are provided to operate the parametric transducer. The input, first and second signals are arranged with a substantially similar frequency to cause a switching frequency of the amplifier circuit to be matched to a carrier frequency of the parametric transducer. A related audio device is also disclosed.