The present application provides a window function processing module including an integrating circuit, configured to receive an integrating input signal, the integrating circuit comprising an operational amplifier; an integrating capacitor, coupled to an output terminal and a first input terminal of the operational amplifier; and an adjustable impedance module, coupled between the first input terminal of the operational amplifier and an integrating input terminal of the integrating circuit, wherein the adjustable impedance module is controlled by at least one control signal to adjust an impedance value of the adjustable impedance module; and a control unit, coupled to the integrating circuit, configured to generate the at least one control signal according to a window function, to adjust the integration gain of the integrating circuit, such that the integrating output signal is related to an operation result of the integrating input signal and the window function.

Provided is an analog front-end circuit for a bioelectric sensor, which includes two feedforward amplifiers and respective feedback networks, an output common-mode voltage detector, an error amplifier, a leakage current compensator and resistance voltage dividers. Common-mode components of various types of leakage currents can be effectively suppressed.

A circuit includes an amplifier, a bias voltage node, and a first set of switches configured, based on a first reset signal having a first value, to couple first and second input nodes to the bias voltage node and to couple first and second output nodes of the amplifier. First and second feedback branches each include a respective RC network including a plurality of capacitances. The first and second feedback branches further include a second set of switches intermediate input nodes and the capacitances, and a third set of switches intermediate input nodes and the plurality of capacitances. These switches selectively couple the capacitances to the input nodes and output nodes, based on a second reset signal having a first value. The second reset signal keeps the first value for a determined time interval exceeding a time interval in which the first reset signal has the first value.

A circuit may include or may be coupled to a precharge structure to reduce or minimize a net perturbation, caused by switching, in the input source. Apparatus and techniques shown herein may enable low input current operation in a signal chain of an analog circuit by such reduction or minimization of such perturbation.

A virtual resistive load feedback circuit for driving a piezoelectric actuator is provided that accounts for a hysteresis error and drift within the movement of the actuator. The circuit may include a voltage divider and charge divider. A voltage monitor signal corresponding to a voltage of a driver signal and a current monitor signal corresponding to a current provided to the amplifier are combined by an operational amplifier and include electrical characteristics of the actuator such that the circuit approximates a virtual load across the actuator. A feedback portion of the operational amplifier may include a resistor and capacitor connected in parallel to provide the voltage and charge divide functions. The use of the virtual resistive circuit allows for the piezoelectric actuator to be ground referenced, with no external components connected directly to the actuator while gaining the feedback effect to counter the hysteresis and drifts errors of the actuator.

An amplifier circuit comprises a multi-stage amplifier having a plurality of amplifiers cascaded between an input port V.sub.in and an output port V.sub.out to form a differential input stage and N subsequent gain stages, a capacitive load C.sub.L coupled to the output port V.sub.out, and a compensation network coupled to the multi-stage amplifier and configured for positioning Pole-Zero pairs of each stage of the multi-stage amplifier below a unity gain frequency ω.sub.t of the multi-stage amplifier when compensated, with Zeros positioned lower than Poles so as to increase the unity gain frequency ω.sub.t.

An analog front-end circuit capable of dynamically adjusting gain includes a programmable gain amplifier (PGA) circuit, a sensor, a calculation circuit, a gain coarse control circuit and a gain fine control circuit. The PGA circuit includes an amplifier, a gain coarse adjustment circuit and a gain fine adjustment circuit. The gain coarse adjustment circuit is controlled by a coarse control signal, and a gain is adjusted in a coarse step according to an initial gain. The gain fine adjustment circuit is controlled by a fine control signal in a data mode, and the gain is adjusted in a fine step. The calculation circuit calculates a primary gain adjustment and a secondary gain adjustment. The gain coarse control circuit generates the coarse control signal according to the primary gain adjustment, and the gain fine control circuit generates the fine control signal according to the secondary gain adjustment.

A resistance device (100) includes a field-effect transistor (TN) and a voltage applying circuit (1). The voltage applying circuit (1) applies a control voltage (Vgs) between the gate and source of the field-effect transistor (TN) according to a temperature (T) to control a resistance value (R) between the drain and source of the field-effect transistor (TN). The control voltage (Vgs) is a voltage obtained by adding a correction voltage (Vc) to a reference voltage (Vgs0). The correction voltage (Vc) depends on the temperature (T) and is set to be zero at a first temperature (T1).

A differential amplifier is provided, in which generation of unnecessary harmonic distortion in the differential output signal is suppressed. A common mode feedback circuit increases or decreases operating points of an inverting output terminal and a non-inverting output terminal such that an intermediate voltage of voltages respectively provided to an inverting input terminal and a non-inverting input terminal is consistent with to a reference voltage. Variations in voltage at the inverting input terminal and the non-inverting input terminal are suppressed, variations in electrical properties of elements connected to the input terminals are suppressed. Therefore, it is possible to suppress generation of harmonic distortion in the output signals from the inverting output terminal and the non-inverting output terminal.

An integrator for use with a current sensor provides a feedback loop reducing drift while maintaining wide bandwidth.