The present invention provides a transducer protection system and method. A transducer module at least comprises a transducer, and a signal source is used for generating a first signal; a protection module is used for predicting an actual displacement and/or temperature of the transducer according to the first signal, an amplification factor of the power amplifier and built-in transducer parameters to generate a prediction result, comparing the prediction result with a preset value to generate an analysis result, and regulating the first signal to form a second signal according to the analysis result; a power amplifier is used for receiving the second signal, and performing power amplification on the second signal to form a driving signal; and the transducer module is used for receiving the driving signal, and at least one transducer in the transducer module can work according to the driving signal.

Various embodiments of the present technology may provide methods and apparatus for a track-and-hold amplifier configured to sample and amplify an analog signal. Methods and apparatus for a track-and-hold amplifier according to various aspects of the present invention may provide an isolation circuit configured to isolate transient current in a track-and-hold capacitor during a track phase. According to various embodiments, selective activation of the isolation circuit provides a settling time that is independent of the gain of the amplifier.

Provided is a multistage amplifier that can achieve both utilizing in a broad bandwidth and suppressing gain reduction. The multistage amplifier includes a plurality of differential amplifiers which are connected in series; and a direct-current component limiter that cuts off a direct-current component of input signals, in which the direct-current component limiter is disposed between the plurality of differential amplifiers, and in which a transistor size of a first differential amplifier which is disposed immediately after the direct-current component limiter is equal to or greater than a transistor size of a second differential amplifier which is disposed two stages before the direct-current component limiter.

An integrated circuit and method for providing a variable gain amplifier are disclosed. One embodiment of the a variable gain amplifier comprises at least one load, a cascode circuit coupled to the load, a folded-gilbert stage, coupled to the cascode circuit, the folded-gilbert stage comprising a main differential pair of transistors and an internal pair of transistors, and a digital to analog converter, coupled to the folded-gilbert stage, for steering currents between the main differential pair of transistors and the internal pair of transistors to change a gain of the variable gain amplifier.

An active device and circuits utilised therewith are disclosed. In an aspect the active device comprises an n-type transistor having a drain, gate and bulk and a p-type transistor having a drain, gate and bulk. The n-type transistor and the p-type transistor include a common source. The device includes a first capacitor coupled between the gate of the n-type transistor and the gale of the p-type transistor, a second capacitor coupled between the drain of the n-type transistor and the drain of p-type transistor and a third capacitor coupled between the bulk of the n-type transistor and the bulk of p-type transistor. The active device has a high breakdown voltage, is memory less and traps even harmonic signals.

Embodiments of circuits for use with an amplifier that includes multiple amplifier paths include a first circuit and a second circuit in parallel with the first circuit. The first circuit includes a first input coupled to a first power divider output, a first output coupled to a first amplifier path of the multiple amplifier paths, and a first adjustable phase shifter and a first attenuator series coupled between the first input and the first output. The second circuit includes a second input coupled to a second power divider output, a second output coupled to a second amplifier path of the multiple amplifier paths, and a second adjustable phase shifter coupled between the second input and the second output.

Feedback circuit for power amplifier. In some embodiments, a radio-frequency amplifier can include a bipolar junction transistor configured to amplify a signal, and having an input and an output. The radio-frequency amplifier can further include a feedback circuit implemented between the output and input of the bipolar junction transistor. The feedback circuit can include a parallel assembly of a field-effect transistor and a resistive element such that the resistive element is bypassed when the field-effect transistor is ON and an overall resistance of the feedback circuit includes the resistive element when the field-effect transistor is OFF. Such a feedback circuit can be configured to be capable of providing a plurality of resistance values between the output and input of the bipolar junction transistor to facilitate different gains of the bipolar junction transistor.

Techniques for controlling one or more audio amplifiers in or associated with a device coupled on a local area network are disclosed. The device receives at least one selected source from other devices also coupled on the network According to one aspect of the techniques, an automatic shutdown control module is provided in the device to power down the audio amplifiers when there is no audio data flow coming to the device or power up the audio amplifiers when there is audio data flow coming to the device. In one embodiment, the procedure to power down or power up the amplifiers is in accordance with a hysteresis, wherein the hysteresis, being lagging of an effect behind its cause, protects the amplifiers and makes the powering-down or powering-up procedure unnoticeable to a user.

A voltage regulator which provides an output current at an output voltage at an output node, based on an input voltage at an input node is described. The voltage regulator has an output amplification stage comprising a pass transistor for deriving the output current at the output node from the input voltage at the input node; and comprising a driver stage to set a gate voltage at a gate of the pass transistor based on a drive voltage. A gain of the output amplification stage is adjustable. Furthermore, the voltage regulator comprises a differential amplification unit to determine the drive voltage in dependence of the output voltage and in dependence of a reference voltage. In addition, the voltage regulator comprises a gain control circuit to adjust the gain of the output amplification stage in dependence of the output current.

A sensor control circuit comprises a sensor (201), a filtering circuit (202), a buffering circuit (203), and an amplifying circuit (204). An output end of the sensor (201) is connected to an input end of the filtering circuit (202), an output end of the filtering circuit (202) is connected to an input end of the buffering circuit (203), and an output end of the buffering circuit (203) is connected to an input end of the amplifying circuit (204). Because the buffering circuit (203) is disposed between the filtering circuit (202) and the amplifying circuit (204), the sensor circuit has an advantage of full sampling. Further provided is an electronic apparatus using the sensor control circuit.