A Doherty amplifier circuit comprising: a splitter having: a splitter-input-terminal for receiving an input signal; a main-splitter-output-terminal; and a peaking-splitter-output-terminal; a main-power-amplifier having a main-power-input-terminal and a main-power-output-terminal, wherein; the main-power-input-terminal is connected to the main-splitter-output-terminal; and the main-power-output-terminal is configured to provide a main-power-amplifier-output-signal; a peaking-power-amplifier having a peaking-power-input-terminal and a peaking-power-output-terminal, wherein: the peaking-power-input-terminal is connected to the peaking-splitter-output-terminal; and the peaking-power-output-terminal is configured to provide a peaking-power-amplifier-output-signal. The splitter, the main-power-amplifier and the peaking-power-amplifier are provided by means of an integrated circuit.

A clamping circuit that may be used to provide efficient and effective voltage clamping in an RF front end. The clamping circuit comprises two series coupled signal path switches and a bypass switch coupled in parallel with the series coupled signal path switches. A diode is coupled from a point between the series coupled signal path switches to a reference potential. In addition, an output selection switch within an RF front end has integrated voltage clamping to more effectively clamp the output voltage from the RF front end. Additional output clamping circuits can be used at various places along a direct gain signal path, along an attenuated gain path and along a bypass path.

A liquid ejecting apparatus includes a drive circuit that outputs a drive signal, wherein the drive circuit includes a modulation circuit that modulates a base drive signal to output a modulation signal, an amplifier circuit that amplifies the modulation signal to output an amplified modulation signal, a demodulation circuit that demodulates the amplified modulation signal to output the drive signal, and a substrate on which the modulation circuit, the amplifier circuit, and the demodulation circuit are provided, wherein the substrate includes a first face and a second face opposite to the first face, wherein the demodulation circuit includes a first coil and a second coil electrically coupled in parallel with the first coil, and wherein the first coil is positioned so as to overlap at least part of the second coil in a direction normal to the first face.

A display apparatus and a method for processing audio are provided, the display apparatus includes a circuit board provided with a hybrid circuit, a filter circuit and a speaker; the hybrid circuit is configured to receive an original audio signal and superpose a first sub-signal of the original audio signal on a second sub-signal of the original audio signal to obtain a hybrid audio signal; the first sub-signal includes at least one channel of audio signal, the second sub-signal includes at least two channels of audio signal; the filter circuit is configured to filter the hybrid audio signal according to a frequency characteristic of the first sub-signal and the second sub-signal to obtain a restored original audio signal; and the speaker, connected with the filter circuit, is configured to output the restored original audio signal.

Certain aspects of the present disclosure generally relate to techniques and apparatus for operating a wireless receiver of the apparatus in a high linearity mode. An example method includes operating the apparatus in a first mode with transmission of a plurality of transmit signals. The method also includes attenuating a received signal via an attenuator while operating the apparatus in the first mode. The method further includes amplifying the attenuated signal with an amplifier while operating the apparatus in the first mode. For certain aspects, the method further involves operating the apparatus in a second mode, bypassing the attenuator while operating the apparatus in the second mode, and amplifying the received signal with the amplifier while operating the apparatus in the second mode.

According to one aspect, an integrated circuit includes a power amplifier having a succession of at least two amplifier stages. The two amplifier stages include a first amplifier stage configured to receive a radio frequency signal as input and a last amplifier stage configured to deliver as an output of an amplified radio frequency signal. The power amplifier further includes a safety circuit with a control circuit configured to compare the amplified radio frequency signal voltage with a threshold voltage. The safety circuit further comprises a gain reduction circuit configured to reduce a bias voltage of an upstream amplifier stage of the last amplifier stage when the amplified radio frequency signal voltage is greater than the threshold voltage.

The present invention is a signal isolation device comprising: a first circulator; a second circulator connected to the first circulator; a first radio frequency switch connected to the second circulator; an adjustable radio frequency limiter connected to the first radio frequency switch; a low noise amplifier connected to the adjustable radio frequency limiter; a bandpass filter connected the low noise amplifier; a power splitter connected the bandpass filter; an attenuator connected to the power splitter; a second radio frequency switch connected to the power splitter; an active filter chain connected to the second radio frequency switch; a third circulator connected to the attenuator and the first circulator; a power detector connected to the third circulator; and a trigger generator connected to the power detector.

A low noise amplifier for an RF sampling analog front end. The amplifier includes digital step attenuation for applying a selected attenuation to signals received at an input node, and a gain stage coupled to amplify the attenuated signal from the digital step attenuation circuit. In a differential amplifier implementation, a first input capacitor is coupled between a positive side input node and an output of the negative side digital attenuation circuit, and a second input capacitor is coupled between a negative side input node and an output of the positive side digital step attenuation circuit. In some embodiments, variable feedback circuits are coupled between each input node and an output of the corresponding gain stage, to selectively apply active termination at the input at high gain settings of the amplifier. Variable input and output resistors, and programmable noise filtering at the output, are provided in some embodiments.

A semiconductor integrated circuit includes a first transmission power mode configured to transmit by a first power, and a second transmission power mode configured to transmit by a second power smaller than the first power, the semiconductor integrated circuit. The semiconductor integrated circuit includes a first transistor configured to receive and amplify a transmission signal in the second transmission power mode, and an attenuator including a resistor element and a switching element, provided between an output of the first transistor and an output terminal, configured to control attenuation of an output signal of the first transistor.

Circuits for protecting devices, such as gallium nitride (VcclGaN) devices, and operating methods thereof are described. The circuits monitor a magnitude of the current in a device and reduce the magnitude of the current and/or shut down the device responsive to the magnitude of the current exceeding a threshold. These circuits safeguard devices from damaging operating conditions to prolong the operating life of the protected devices.