In an operational amplifier, a differential amplifying circuit is configured to amplify an input voltage inputted from the input terminal. An outputting transistor is connected to the output terminal. A driving transistor is connected to the differential amplifying circuit and the outputting transistor. The driving transistor turns on according to a control signal supplied from the differential amplifying circuit to the driving circuit. The driving transistor is also configured to drive the outp...

An operational amplifier has a differential amplifier stage comprising a pair of first PMOS transistors for inputting signals, which are arranged between a positive voltage supply coupled with a first constant current source and a negative voltage supply, wherein second PMOS transistors of a high voltage resistant type, gates of which are biased to a prescribed voltage, are arranged on current paths lying between the first PMOS transistors and the negative voltage supply together with load resis...

An operational amplifier that decreases idling current, widens a voltage output range, and increases load driving capacity. The operational amplifier includes a first output transistor connected to a high potential power supply. A second output transistor is connected between the first output transistor and a low potential power supply. The first and second output transistors generate an output signal at a node between the first output transistor and the second output transistor. An idling curre...

The performance of a conventional op amp, having a g.sub.m stage and an integrator, is improved by placing a current mode filter between the g.sub.m stage and the integrator, which has a current gain of much less than one and is substantially without phase shift at the op amp's resonant frequency, permitting stabilization with a relatively small compensation capacitor. This improves the signal slew rate and harmonic distortion.

An operational amplifier includes a differential amplification circuit, a voltage amplification circuit, a capacitor, and a bias setting circuit. The differential amplification circuit includes load transistors arranged in a cascode connection. The voltage amplification circuit forms a stage following the differential amplification circuit. The capacitor couples the differential amplification circuit and the voltage amplification circuit with each other. The bias setting circuit charges the capa...

An operational amplifier for increasing the response speed of its output voltage relative to an input signal while increasing the tolerable amplitude of the output voltage. The operational amplifier includes a PNP output transistor connected to a high potential power supply, an NPN output transistor connected between the PNP output transistor and a low potential power supply, and a drive unit, which drives each output transistor in accordance with an input current. The drive unit includes a curr...

The present invention is a folded cascode operational amplifier provided with a differential input portion 10, cascode current source portion 20, current mirror portion 30, output portion 40, and differential amplifier 50 serving as a differential amplifying portion. The differential input portion 10 has P-type MOS transistors M2 and M3 of a differential pair for respectively inputting a differential signal and the MOS transistors M2 and M3 are respectively provided with a well terminal. The dif...

An operational amplifier includes a current provider that introduces an additional current Ic to an internal node A of the operational amplifier for reducing the output offset voltage of the operational amplifier.

An operational amplifier is described. The operational amplifier includes a first stage, a second stage, a third stage, and a fourth stage. The amplifier includes a nested transconductance-capacitance compensation configuration. The third stage includes class AB control mechanism. The fourth stage includes a class AB output stage.

An operational amplifier that decreases idling current, widens a voltage output range, and increases load driving capacity. The operational amplifier includes a first output transistor connected to a high potential power supply. A second output transistor is connected between the first output transistor and a low potential power supply. The first and second output transistors generate an output signal at a node between the first output transistor and the second output transistor. An idling curre...