US 6,005,440 A · Operational amplifier

Abstract

An operational amplifier capable of supplying a large power approximate to a power supply voltage to a load resistance and of rendering the current consumption relative to the power supply voltage small when a signal is not issued. The operational amplifier comprises a first differential amplifying stage, a first amplifying stage, a first level shifting stage, a second differential amplifying stage, a second amplifying stage, a second level shifting stage, and outputting stage, a first phase compensation circuit and a second compensation circuit. The first differential amplifying stage differentially amplifies input signals while n-channel transistors serves as a differential amplifying elements. The second differential amplifying stage differentially amplifies input signals while p-channel transistors serves as a differential amplifying elements. The first amplifying stage amplifies an output of the first differential amplifying stage in opposite phase. The second amplifying stage amplifies an output of the second differential amplifying stage in opposite phase. The outputting stage comprising a p-channel transistor a source of which is connected to a first power supply voltage and an n-channel transistor a source of which is connected to a second power supply voltage for executing complementary operation in response to outputs of the first and second differential amplifying stages. The first level shifting stage level shifts an output of the first amplifying stage in the direction of the first power supply voltage to control a gate of the n-channel transistor of the outputting stage. The second level shifting stage level shifts an output of the second amplifying stage in the direction of the second power supply voltage to control a gate of the p-channel transistor of the outputting stage.

Claims20

Dependent claims

An operational amplifier comprising;

a first differential amplifying stage for differentially amplifying input signals comprising n-channel MOS transistors serving as differential amplifying elements;
a second differential amplifying stage for differentially amplifying input signals comprising p-channel MOS transistors serving as differential amplifying elements;
a first amplifying stage for amplifying an output of the first differential amplifying stage in opposite phase;
a second amplifying stage for amplifying an output of the second differential amplifying stage in opposite phase;
an outputting stage comprising a p-channel transistor a source of which is connected to a first power supply voltage and an n-channel transistor a source of which is connected to a second power supply voltage for executing complementary operation in response to outputs of the first and second differential amplifying stages;
a first level shifting stage for level shifting an output of the first amplifying stage in the direction of the first power supply voltage to control a gate of the n-channel transistor of the outputting stage;
and
a second level shifting stage for level shifting an output of the second amplifying stage in the direction of the second power supply voltage to control a gate of the p-channel transistor of the outputting stage.

5 more elements

An operational amplifier comprising first and second differential amplifying means for differentially amplifying input signals, first and second amplifying means for amplifying outputs of the first and second differential amplifying means, first and second level shifting means for level shifting outputs of the first and second amplifying means, and outputting means having a p-channel MOS transistor a source of which is connected to a first power supply voltage, and an n-channel MOS transistor a source of which is connected to a second power supply voltage, said outputting means executing complementary operation in response to outputs of the first and second level shifting means, wherein the operational amplifier further comprises:

first and second overcurrent detecting circuits for detecting outputs of the first and second level shifting means;
and
first and second current compensation means for compensating increments of current of the first and second amplifying means in response to detected outputs of the first and second overcurrent detecting circuits.

Dependencies are inferred from the claim text.

Operational amplifier

Life of this patent

Operational amplifier

Life of this patent

Abstract

Claims20