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US 8,264,277 B2Granted
Differential amplifier circuit
AssigneeSeiko Instruments Inc.
InventorsAtsushi Igarashi, Masahiro Mitani
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Abstract
Provided is a differential amplifier circuit in which an offset voltage is independent from input voltages. A first correction current generation circuit and a second correction current generation circuit are provided and configured to cause the same current as a current flowing through a folded cascode amplifying stage to flow into an output stage. Accordingly, transistors included in the folded cascode amplifying stage and transistors included in the output stage have the same bias condition.
Claims4
A differential amplifier circuit, comprising:
- a first input stage comprising a pair of PMOS transistors and a first current source, for causing an output current to flow based on two input voltages;
- a second input stage comprising a pair of NMOS transistors and a second current source, for causing an output current to flow based on the two input voltages;
- a folded cascode amplifying stage, into which the output current of the first input stage flows and from which the output current of the second input stage is drawn, thereby outputting a voltage;
- an output stage for outputting an output voltage based on the voltage of the folded cascode amplifying stage;
- a first correction current generation circuit for causing a first correction current to flow into the output stage based on a supply current of the first current source;
- and
- a second correction current generation circuit for drawing a second correction current from the output stage based on a supply current of the second current source.
4 more elements
Dependencies are inferred from the claim text.