US 2009/0289930 A1 · Operational amplifier circuit and display panel driving apparatus

Abstract

An operational amplifier circuit includes: an input stage for generating an internal current corresponding to a potential difference between inverting and non-inverting input terminals; and an output stage for driving an output terminal in response to the internal current. The output terminal includes: a floating current source through which the internal current flows; a PMOS transistor for driving the output terminal corresponding to a potential of a first terminal of the floating current source; and an NMOS transistor for driving the output terminal corresponding to a potential of a second terminal of the floating current source. The floating current source includes: a PMOS transistor whose source and drain are respectively connected to the first and second terminals; and an NMOS transistor whose drain and source are respectively connected to the first and second terminals. A back gate of the latter PMOS transistor is connected to the source thereof.

Claims17

Dependent claims

An operational amplifier circuit comprising:

an input stage which generates a first internal current corresponding to a potential difference between an inverting input terminal and a non-inverting input terminal;
and
an output stage which drives an output terminal corresponding to the first internal current, wherein
the output stage includes:
a first floating current source through which the first internal current flows;
a first output transistor which drives the output terminal corresponding to a potential of a first terminal of the first floating current source;
and
a second output transistor which drives the output terminal corresponding to a potential of a second terminal of the first floating current source,
the first floating current source includes:
a first PMOS transistor whose source and drain are respectively connected to the first and second terminals;
and
a first NMOS transistor whose drain and source are respectively connected to the first and second terminals, and
in at least one of the first PMOS transistor and the first NMOS transistor, a back gate is connected to a source.

10 more elements

A display panel driving apparatus for generating a driving voltage for driving a display panel, the apparatus comprising:

a positive-side amplifier which generates a first driving voltage in a range between a power supply voltage and an intermediate power supply voltage that is a half of the power supply voltage;
and
a negative-side amplifier which generates a second driving voltage in a range between a ground voltage and the intermediate power supply voltage, wherein
each of the positive-side amplifier and the negative-side amplifier includes:
an input stage which generates an internal current corresponding to a potential difference between an input terminal and an output terminal;
and
an output stage which outputs any one of the first and second driving voltages from the output terminal corresponding to the internal current,
the output stage includes:
a floating current source through which the internal current flows;
a first output transistor which drives the output terminal corresponding to a potential of a first terminal of the floating current source;
and
a second output transistor which drives the output terminal corresponding to a potential of a second terminal of the floating current source,
the floating current source includes:
a PMOS transistor whose source and drain are respectively connected to the first and second terminals;
and
an NMOS transistor whose drain and source are respectively connected to the first and second terminals,
in the PMOS transistor in the floating current source in the output stage of the positive-side amplifier, a back gate is connected to the source, and
in the NMOS transistor in the floating current source in the output stage of the negative-side amplifier, a back gate is connected to the source.

15 more elements

A display panel driving apparatus for generating a driving voltage for driving a display panel, the apparatus comprising:

a grayscale voltage supplying circuit which supplies a plurality of grayscale voltages;
a D/A converter which selects one of the plurality of grayscale voltages depending on image data;
and
an amplifier which generates a driving voltage corresponding to the selected grayscale voltage, wherein
the grayscale voltage supplying circuit includes:
a positive-side γ amplifier which generates a positive-side bias voltage in a range between a power supply voltage and an intermediate power supply voltage that is a half of the power supply voltage;
a negative-side γ amplifier which generates a negative-side bias voltage in a range between the intermediate power supply voltage and a ground voltage;
and
a ladder resistor which generates the grayscale voltages through voltage division upon receipt of the positive-side bias voltage and the negative-side bias voltage,
each of the positive-side γ amplifier and the negative-side γ amplifier includes:
an input stage which generates an internal current corresponding to a potential difference between an input terminal and an output terminal;
and
an output stage which outputs any one of the positive-side bias voltage and the negative-side bias voltage from the output terminal in response to the internal current,
the output stage includes:
a floating current source through which the internal current flows;
a first output transistor which drives the output terminal corresponding to a potential of a first terminal of the floating current source;
and
a second output transistor which drives the output terminal corresponding to a potential of a second terminal of the floating current source,
the floating current source includes:
a PMOS transistor whose source and drain are respectively connected to the first and second terminals;
and
an NMOS transistor whose drain and source are respectively connected to the first and second terminals,
in the PMOS transistor in the floating current source in the output stage of the positive-side γ amplifier, a back gate is connected to the source, and
in the NMOS transistor in the floating current source in the output stage of the negative-side γ amplifier, a back gate is connected to the source.

21 more elements

Dependencies are inferred from the claim text.

Operational amplifier circuit and display panel driving apparatus

Life of this patent

Operational amplifier circuit and display panel driving apparatus

Life of this patent

Abstract

Claims17