An apparatus comprises a transistor pair including a first metal oxide semiconductor field effect transistor (MOSFET) coupled to a second MOSFET. The first MOSFET includes a first gate terminal and a first drain terminal. The second MOSFET comprises a second gate terminal and a second drain terminal. The first gate terminal is configured to receive a first signal. The second gate terminal is configured to receive a second signal that is phase shifted with respect to the first signal. An output node is coupled to the first drain terminal and the second drain terminal and configured to output a third signal that is proportional to a power of the first signal and the second signal.

One embodiment is an apparatus including a detector circuit electrically coupled between a signal source and a second circuit, the signal source generating a first signal, the detector circuit detecting a level of the first signal and generating a first control signal when the detected level of the first signal exceeds a first threshold value, and a clamping switch electrically coupled to receive the first control signal from the detector circuit, the clamping switch including a multi-terminal active device. The first control signal controls a state of the clamping switch such that the clamping switch clamps a level of a signal applied to the second circuit when the level of the first signal exceeds the first threshold value.

A radar sensing system includes a transmitter and a receiver. The transmitter is configured for installation and use in a vehicle and configured to transmit radio signals. The receiver is configured for installation and use in the vehicle and configured to receive radio signals that include the transmitted radio signals transmitted by the transmitter and reflected from objects in an environment. The receiver includes a plurality of inputs and a plurality of low noise amplifiers (LNAs). Each input of the plurality of inputs is communicatively coupled to a corresponding LNA of the plurality of LNAs. The plurality of LNAs are co-located, and respective outputs of the plurality of LNAs are all directly coupled together at a connection point.

An RF power detector adapted to detect an RF power of an RF signal, includes, in part, an antenna adapted to receive the RF signal, a narrow-band RF power converter adapted to convert the RF signal to a DC signal, an accelerometer, and a magnetometer. The accelerometer and magnetometer are adapted to determine the orientation and location of the power detector. The power detector optionally includes a gyroscope. The narrow-band RF power converter may be a rectifier tuned to the frequency of the RF signal. The power detector optionally includes an indicator adapted to provide information representative of the amount of the DC power of the DC signal, as well as position and orientation of the power detector. The power detector may be adapted to be inserted into a mobile device so as to provide the information about the amount of DC power, orientation and position to the mobile device.

A receiver has a differential transimpedance amplifier (4) with two inputs and two outputs. The differential transimpedance amplifier (4) provides a differential output and this is peak-detected (15, 16) to provide amplitude reference signals. The differential transimpedance amplifier output and the amplitude reference signals are fed to a differential summing amplifier (10), which provides a fully differential signal to a comparator, or to an automatic gain control circuit (5) to regulate the differential transimpedance amplifier gain. The differential summing amplifier (10) output is a fully differential signal, thereby having lower distortion for DC and burst mode receiver applications.

An apparatus, such as a coherent optical receiver, includes a transimpedance amplifier (TIA) with differential outputs, and a multi-tanh type current limiter connected across the differential outputs of the transimpedance amplifier. The multi-tanh type current limiter includes two tanh-type current limiters shifted in voltage and connected to subtract an output current thereof from an output current of the TIA.

Reference oscillators are ubiquitous in timing applications generally, and in modern wireless communication devices particularly. Microelectromechanical system (MEMS) resonators are of particular interest due to their small size and potential for integration with other MEMS devices and electrical circuits on the same chip. In order to support their use in high volume low cost applications it would be beneficial for MEMS designers to have MEMS resonator designs and manufacturing processes that whilst employing low cost low resolution semiconductor processing yield improved resonator performance thereby reducing the requirements of the oscillator circuitry. It would be further beneficial for the oscillator circuitry to be able to leverage the improved noise performance of differential TIAs without sacrificing power consumption.

Peak voltage limiting circuits and method for power amplifiers. A power amplifier and/or a voltage limiting circuit includes a diode circuit coupled to an output of an amplification stage, the diode circuit configured to provide a conductive path from the output when an output voltage exceeds a selected value. The power amplifier and/or voltage limiting circuit also includes a sink circuit coupled to the diode circuit and a bias circuit, the sink circuit configured to reduce a bias voltage provided by the bias circuit when the output voltage exceeds the selected value to thereby limit the output voltage.

A power amplifier with supply switching is provided. The power amplifier detects a magnitude of an outgoing broadband communication signal and determines whether the magnitude exceeds a predetermined voltage threshold. The power amplifier applies a first gain to the outgoing broadband communication signal using a first voltage supply rail when it is determined that the magnitude exceeds the predetermined voltage threshold and a second gain using a second voltage supply rail that is smaller than the first voltage supply rail when it is determined that the magnitude does not exceed the predetermined voltage threshold. The power amplifier produces an output signal from the outgoing broadband communication signal with the applied first gain or the applied second gain, wherein a current of the outgoing broadband communication signal is switched between the first voltage supply rail and the second voltage supply rail in response to the magnitude being detected.

In some embodiments, a method for operating a radio-frequency amplifier can include providing a bias signal to an amplifier implemented between an input node and an output node, and generating a detected voltage representative of a peak of a radio-frequency signal present at the input node. The method can further include enabling a protection mode when the detected voltage is greater than a first threshold value and disabling the protection mode when the detected voltage is less than a second threshold value that is less than the first threshold value.