An amplification apparatus includes an amplifier having an inverting terminal, and a non-inverting terminal connected to a reset voltage node, a first capacitor connected to the inverting terminal, an input voltage being applied to the first capacitor, a second capacitor connected to the inverting terminal and an output terminal of the amplifier, and a duty-cycled resistor, connected in parallel to the second capacitor, including a first resistor. The duty-cycled resistor is configured to connect the first resistor and the inverting terminal and to disconnect the first resistor and the reset voltage node during a first time interval included in a period to complete an on-and-off cycle of the duty-cycled resistor, and disconnect the first resistor and the inverting terminal and to connect the first resistor and the reset voltage node during a second time interval included in the period.

A system for sensing an electrical quantity may include a sensing stage configured to sense the electrical quantity and generate a sense signal indicative of the electrical quantity, wherein the electrical quantity is indicative of an electrical signal generated by a Class-DG amplifier configured to drive a load wherein the Class-DG amplifier has multiple signal-level common modes and a common-mode compensator configured to compensate for changes to a common-mode voltage of a differential supply voltage of the driver occurring when switching between signal-level common modes of the Class-DG amplifier.

Disclosed in various embodiments of the present invention are a method and a device comprising: a first electrode, a second electrode and a third electrode which make contact with the body of a user; an instrumentation amplifier for differentially amplifying signals received from the first electrode and the second electrode; a feedback amplifier for feeding back feedback noise to the body of the user through the third electrode; and a control circuit, wherein the control circuit is configured to analyze a noise level by using a biosignal obtained from the instrumentation amplifier, and control the gain of the feedback amplifier on the basis of the result of the analysis. Various embodiments are possible.

An active filter reduces Electro-Magnetic Interference (EMI) created by current flowing through a power line. The active filter connects to the power line at a single node through a connection capacitor. A sense current flows through the connection capacitor when the power line current changes. This sense current is applied to a non-inverting input of an op amp to drive a power amplifier circuit through a filter capacitor. The power amplifier circuit increases the current drive of the op amp to charge a transfer capacitor that converts the power amplifier output current to a transfer voltage. The transfer capacitor is connected to the connection capacitor so that the transfer voltage is injected back into the power line through the connection capacitor as an injected voltage that compensates for the sensed current. Op amp gain is adjustable by variable resistors that connect to the inverting input of the op amp.

A differential to single-ended buffer amplifier with a swing suppression resistor in the differential amplification architecture is shown. The differential to single-ended buffer amplifier has a positive input terminal, a negative input terminal, a differential to single-ended operational amplifier (DISO op amp), and a swing suppression resistor. The DISO op amp has a non-inverting input terminal and an inverting input terminal respectively coupled to the positive input terminal and the negative input terminal, and it has a single-ended output terminal that outputs the output signal of the differential to single-ended buffer amplifier. The swing suppression resistor is connected between the negative input terminal of the differential to single-ended buffer amplifier and the non-inverting input terminal of the DISO op amp.

A circuit arrangement comprises a first input node, a first output node, a sampling capacitor means and a first switching means being switchable between a first switching state and a second switching state. The first switching means is coupled to the sampling capacitor means, the first input node and the first output node in such a way that the sampling capacitor means is conductively connected to the first input node and disconnected from the first output node in the first switching state and the sampling capacitor means is disconnected from the first input node and conductively connected to the first output node in the second switching state. A first charge-storing element is coupled via a second switching means to the first input node in such a way that the charge-storing element is charged in the first switching state and discharged in the second switching state, thereby at least partly compensating current flow for charging the sampling capacitor means in the first switching state.

An embodiment voltage-current converter circuit comprises a first amplifier and a second amplifier having homologous first input nodes configured to receive a voltage signal therebetween as well as homologous second input nodes having a resistor coupled therebetween. First and second current mirror circuits are provided comprising first input transistors having their control terminal coupled to the output nodes of the amplifiers. First and second current sensing circuitry having first and second current output nodes are coupled to the current mirror output nodes of the current mirror circuits and configured to provide therebetween a current which is a function of the voltage signal between the homologous first input nodes of the amplifier.

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.

An operational amplifier integrated circuit includes a differential pair of transistors having a first input, a second input. A bias current generator applies a bias current to an output of the differential pair of transistors. A control loop generates a control voltage arising from a difference in potentials between the first input and the second input. An additional current that is added to the bias current is generated in response to the control voltage.

The present invention provides a circuit having a filter with an amplifier circuit for filtering and amplifying an input signal to generate an output signal, wherein a corner frequency of the filter is adjustable to control a settling time of the output signal.