An operational amplifier having a first amplifier stage and a second amplifier stage, which is driven by the first amplifier stage. According to the invention such an operational amplifier can be corrected for high frequencies in a very simple and effective manner by including a capacitance in parallel with the second amplifier stage between an output of the first stage and an output of the second stage which is comparatively high-ohmic relative to said output of the first stage. The second stag...

An operational amplifier comprises a differential input stage, first and second folded cascode stages connected to the differential input stage, and first and second output inverting amplifiers. The first output inverting amplifier is driven by the output of the first folded cascode stage, and the second output inverting amplifier is driven through a current mirror by the output of the second folded cascode stage, such that a push pull output stage is provided in the operational amplifier. As a ...

An operational amplifier for constituting an apparatus such as, for instance, an analog computer. The amplifier has a very high input impedance so that only a very low value of signal current is drawn from the signal source. A stationary component in the signal voltage appearing at the signal input terminal is amplified by a chopper-stabilized direct-current amplifier having a chopper and a synchronous demodulator, and then is applied to a feedback point located at the junction between the two o...

A fully differential operational amplifier has a high DC gain and a high common mode feedback gain and produces an output voltage with rise and fall times shortened to the same extent. The operational amplifier comprises a first stage composed of MOS transistors M21 through M9, a drive stage composed of MOS transistors M10 through M17, and a phase-compensating circuit composed of MOS transistors M18, M19 and capacitive elements C1, C2. The drive stage is of a push-pull configuration of the MOS t...

An operational amplifier includes differential amplification circuitry and current mirror circuitry. The differential amplification circuitry includes first and second differential amplification circuits disposed symmetrically in the upper and lower parts of a circuit diagram, and the current mirror circuitry includes first and second current mirror circuits disposed symmetrically in the upper and lower parts of the circuit diagram. The input ends of the first and second differential amplificati...

An operational amplifier comprising output stages K2 and K3 for outputting an output signal So in response to an input signal Si, wherein; said output stages perform a push-pull operation respectively in response to a plurality of specific signals generated on the basis of said input signal and have a plurality of output stage transistors M65 and M66 for generating said output signal as a result of said push-pull operation, and said plurality of specific signals are generated as signals being su...

An operational amplifier includes a differential amplifier stage having positive and negative input terminals formed by a pair of differential amplifier circuits, a current mirror stage having a pair of current mirror circuits coupled to the differential amplifier stage and producing a common output, and a buffer circuit having a current source connected to the common output of the current mirror stage, wherein the buffer circuit includes a plurality of first input transistors and plurality of s...

In order to reduce power consumption and prevent crossover distortion, the difference between a negative phase input voltage and a positive phase input voltage is amplified at a differential stage and a differential output voltage is output. The state of continuity of an NMOS transistor is controlled with the differential output voltage. By controlling the product of the current flowing through a resistor and the resistance value of this resistor, the level shift voltage at a level shift stage c...

An operational amplifier including reverse amplifiers interconnected in series in an odd number of stages not less than three, an element for feeding back an output from the reverse amplifier in the last stage to an input of the reverse amplifier in a first stage, and a feedback capacitance element provided across the input and output ends of at least one of the reverse amplifiers. The Miller effect makes the feedback current from the capacitance element appear as if it were increased by a facto...

An operational amplifier for canceling an offset and continuously generating an output signal. The operational amplifier includes a first operational amplification unit and a second operational amplification unit each having at least one electrical characteristic that is substantially the same as one another. One of the operational amplification units performs a canceling operation (holding operation and compensation operation) of the offset voltage while the other operational amplification unit...