An amplifier circuit according to an embodiment includes a first circuit, a second circuit, and a third circuit. The first circuit includes a first transistor connected between an input node through which an input current flows and a reference potential node. The first transistor has a gate electrode connected to the input node. The second circuit includes a low-pass filter circuit and a second transistor connected in parallel to the first transistor between the input node and the reference potential node. The second transistor has a gate electrode connected to the gate electrode of the first transistor via the low-pass filter circuit. The third circuit includes a third transistor connected between an output node through which an output current flows and the reference potential node, the third circuit having a gate electrode connected to the gate electrode of the first transistor.

An integrated circuit includes a transimpedance amplifier and an injection circuit. The injection circuit generates a first electrical test signal and injects the first electrical test signal into the transimpedance amplifier. The first electrical test signal or an output of the transimpedance amplifier generated based on the first electrical test signal is used to determine whether the integrated circuit is faulty.

A reception circuit includes an input terminal configured to receive an input current; a voltage signal circuit being configured to convert a current signal into a voltage signal; a reference voltage circuit configured to generate a reference voltage in accordance with a first feedback current; a differential amplifier circuit configured to generate a differential signal in accordance with a voltage difference between the voltage signal and the reference voltage; and an offset control circuit configured to generate the first feedback current and a second feedback current, adjust the first feedback current when the voltage signal has an average voltage value greater than the reference voltage, and subtract the second feedback current from the input current such that the offset of the differential signal falls within the tolerance when the voltage signal has an average voltage value smaller than the reference voltage.

A tuning fork sensor system places a controlled bias on the proof-mass drive-axis electrodes to cancel the quadrature charge. Also, its charge amplifiers employ a field-effect transistor biased slightly into the triode region so that it behaves as a very large value resistor. In addition, it uses a phase-locked loop having a special loop filter in order to optimize performance by rejecting off-frequency drive feedthrough to the motor pick-off while resulting in very low phase wander for the demodulation references.

A tuning fork sensor system places a controlled bias on the proof-mass drive-axis electrodes to cancel the quadrature charge. Also, its charge amplifiers employ a field-effect transistor biased slightly into the triode region so that it behaves as a very large value resistor. In addition, it uses a phase-locked loop having a special loop filter in order to optimize performance by rejecting off-frequency drive feedthrough to the motor pick-off while resulting in very low phase wander for the demodulation references.

The present disclosure provides for process and temperature compensation in a transimpedance amplifier (TIA) using a dual replica via monitoring an output of a first TIA (transimpedance amplifier) and a second TIA; configuring a first gain level of the first TIA based on a feedback resistance and a reference current applied at an input to the first TIA; configuring a second gain level of the second TIA and a third TIA based on a control voltage; and amplifying a received electrical current to generate an output voltage using the third TIA according to the second gain level. In some embodiments, one or both of the second TIA and the third TIA include a configurable feedback impedance used in compensating for changes in the second gain level due to a temperature of the respective second or third TIA via the configurable feedback impedance of the respective second or third TIA.

An amplifier includes a first amplification circuit, a second amplification circuit including first and second amplification transistors controlled by the first amplification circuit to generate first and second output signals and a bias transistor turned on based on a bias signal to generate the first output signal, a filter circuit including a bias capacitor connected to the first amplification transistor and the bias transistor to generate the first bias signal using a first bias voltage, and a feedback circuit configured to receive the first and second output signals and output a feedback signal that adjusts an average of the first and second output signals to correspond to a reference signal, to the first amplifier. The filter circuit adjusts a voltage of the bias capacitor such that a voltage of the bias capacitor when the amplifier is disabled corresponds to a voltage of the bias capacitor when the amplifier is enabled.

Disclosed is an operational amplifier based on a metal-oxide TFT. The operational amplifier includes an auxiliary amplifier and a bootstrap gain-increasing amplifier. The auxiliary amplifier adopts a two-stage positive feedback structure, including a fifth transistor, a seventh transistor, an eleventh transistor, a first amplifying unit, and a second amplifying unit. A gate of the fifth transistor serves as an input end of the operational amplifier. The bootstrap gain-increasing amplifier includes two second circuits in mutual symmetry. Each of the second circuits includes a first transistor, a second transistor, and a current source unit with a bootstrap structure.

A single servo control loop for amplifier gain control based on signal power change over time or system to system, having an amplifier configured to receive an input signal on an amplifier input and generate an amplified signal on an amplifier output. The differential signal generator processes the amplified signal to generate differential output signals. The single servo control loop processes the differential output signal to generates one or more gain control signals and one or more current sink control signals. A gain control system receives a gain control signal and, responsive thereto, controls a gain of one or more amplifiers. A current sink receives a current sink control signal and, responsive thereto, draws current away from the amplifier input. Changes in input power ranges generate changes in the integration level of the differential signal outputs which are detected by the control loop, and responsive thereto, the control loop dynamically adjusts the control signals.

Techniques are disclosed to compensate for changes in the impedance of stage(s) preceding a trans-impedance amplifier (TIA) that is used within an RF chain. The techniques identify the changes in the source impedance value of the input stage (e.g., the mixers and LNAs) as a result of a gain state change, which alters the signal-to-transfer function (STF) of the TIA during operation and negatively impacts radio performance. The STF is maintained for changes in the source impedance value throughout different gain states without using switchable shunt components by using tunable elements to compensate for the source impedance changes, thus keeping the STF constant.