A circuit for use in a system that includes a detector, wherein the circuit comprises an input terminal to receive a detector signal from the detector external to the circuit, the detector signal to include an error charge corresponding to a leakage current. The circuit further comprises an amplifier coupled to the input terminal to receive input signals corresponding to the detector signal, including the error charge applied to an input of the amplifier. The circuit further comprises a feedback path coupled across the amplifier, wherein the feedback path comprises a first switch coupled across a leakage resistor and to a leakage capacitor for discharging a feedback compensation charge from the leakage capacitor and onto the input of the amplifier to substantially cancel the error charge.

A common source preamplifier for a MEMS capacitive sensor is disclosed. The preamplifier is a single-stage amplifier employing negative feedback. The preamplifier provides stable gain independent of temperature and at the same time provides effective buffering for a subsequent stage. Further, the preamplifier may be configured to provide different values of gain. Furthermore, the preamplifier has lower noise and consumes lesser area and lesser power than prior art.

An electronic circuit for a micro-electro-mechanical systems gyroscope is disclosed. The electronic circuit includes a current buffer, a transimpedance amplifier coupled with the current buffer, and a plurality of transistors. An inverting input terminal of the current buffer and a non-inverting input terminal of the current buffer are connected with a plurality of first resistors. The inverting input terminal of the current buffer is connected with a source of one of the plurality of transistors, and the non-inverting input terminal of the current buffer is connected with a source of another one of the plurality of transistors. The plurality of first resistors are connected to a ground. The current buffer is configured to isolate a load in the micro-electro-mechanical systems gyroscope from the transimpedance amplifier.

There is provided an RF amplifier arrangement comprising: an input operable to receive an RF input signal; an output operable to output an amplified RF signal; at least one amplifier bank located between the input and output, the or each amplifier bank comprising a plurality of amplifier stages; an input level detector operable to measure the signal level of the RF input signal; and a controller operable to control the amplifier bank, wherein the controller is operable to select one or more different configurations of the amplifier by selecting one or more amplifier stages and/or modifying one or more characteristics of one or more amplifier stages in dependence upon the signal level of the RF input signal to dynamically adapt and optimise its characteristics.

A circuit for filtering a signal corresponding to a time of flight (TOF) of light from a laser reflected off an object to a photo detector, the circuit includes a preamplifier, a DC cancelation loop, and an AC cancelation loop. The preamplifier may be configured to receive the signal from the photo detector corresponding to an output of the laser reflected off an object remote from the laser and photo detector. The DC cancelation loop includes a current feedback DC servo loop. The AC cancelation loop includes a feedback network driven by a floating class AB output stage, and the preamplifier configured to drive the floating class AB output stage, wherein the preamplifier is driven by an error signal of the feedback network and creates an AC signal path with the feedback network and floating class AB output stage.

Embodiments of the present disclosure provide a current amplification circuitry and a driving method thereof, and a fingerprint detection device. The current amplification circuitry includes a voltage control circuit, a plurality of first current amplification circuits, and a second current amplification circuit. The voltage control circuit provides a voltage control signal to the plurality of first current amplification circuits. The first current amplification circuit includes a current mirror, and the current mirror is coupled to a voltage input terminal, the voltage control circuit, and a first input terminal of the second current amplification circuit. The first current amplification circuit amplifies a current from the voltage input terminal according to the voltage control signal provided by the voltage control circuit, and provides the amplified current to the second current amplification circuit. The second current amplification circuit is coupled to the voltage input terminal via a second input terminal and amplifies the amplified current.

This application relates to circuitry for monitoring for instability of an amplifier. The amplifier (100) has a first signal path between an amplifier input (IN.sub.N) and an amplifier output (V.sub.OUT) and a feedback path from the output to form a feedback loop with at least part of the first signal path. A comparator (212) has a first input configured to receive a first signal (IN.sub.N) derived from a first amplifier node which is part of said feedback loop and a second input configured to receive a second signal (IN.sub.P) derived from a second amplifier node which varies with the signal at the amplifier input but does not form part of said feedback loop. The comparator is configured to compare the first signal to the second signal and generate a comparison signal (COMP), wherein in the event of amplifier instability the comparison signal comprises a characteristic indicative of amplifier instability.

A radiofrequency transmission/reception integrated circuit includes at least one radiofrequency signal amplifier (PA, LNA), the at least one amplifier being configured, in operational mode, so as to perform a function of amplifying a radiofrequency signal applied at input, wherein the amplifier is configured so as to perform an oscillator function in a self-test mode of the integrated circuit, to generate a radiofrequency signal on at least one of the input or the output of said amplifier. A self-test method for such an integrated circuit is also provided.

An embodiment of an amplifier circuit includes first, second, and third amplifiers. The first and second amplifiers, each of which can be a respective operational amplifier or a respective transconductance amplifier, are configured to amplify a differential input signal with a non-inverting gain. And the third amplifier, which can be an operational amplifier or a transconductance amplifier, is configured to cause the first and second amplifiers to amplify a common-mode input signal with a gain that is less than unity. The third amplifier can also be configured to cause the first and second amplifiers to generate a common-mode output voltage that is substantially independent of the common-mode input voltage. Consequently, in addition to presenting a high input impedance and a low noise factor, such an amplifier circuit has a configurable common-mode output voltage and has a lower common-mode gain (e.g., less than unity, approaching zero) than other non-inverting differential amplifiers.

A provided impedance measuring semiconductor circuit can suppress the influence of sensors on the measurements of other sensors in the measurements of the sensors. According to an embodiment, an impedance measuring semiconductor circuit includes a first resistance element, an operational amplifier having a positive input terminal and an output terminal, the positive input terminal receiving a predetermined set voltage, the output terminal being coupled to one end of the first resistance element, a first output-side switch that electrically couples or decouples a first sensor and the other end of the first resistance element, a second output-side switch that electrically couples or decouples a second sensor and the other end of the first resistance element, a first input-side switch that electrically couples or decouples the first sensor and a negative input terminal, and a second input-side switch that electrically couples or decouples the second sensor and the negative input terminal.