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US 2003/0146923 A1Published application
Amplifier circuit, driving circuit of display apparatus, portable telephone and portable electronic apparatus
AssigneeNEC Corporation
InventorsYoshihiko Nakahira, Hiroshi Tsuchi
Life of this patent
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Abstract
To obtain an amplifier circuit capable of realizing low power consumption and high-precision output. A controlling unit controls each switch of an offset correction circuit to select one capacitor associated with a voltage level of an input signal selected by an input signal selection unit, have an offset voltage of an operational amplifier generated according to the voltage level of the input signal stored by the selected capacitor, and correct an output of the operational amplifier by using the offset voltage held by the selected capacitor.
Claims55
An amplifier circuit comprising:
- an operational amplifier for amplifying an input signal capable of having a plurality of voltage levels;
- storing means for storing in advance each of offset voltages generated to said operational amplifier according to the voltage level of said input signal;
- and
- controlling means for correcting output of said operational amplifier by using said offset voltage stored in said storing means.
1 more element
An amplifier circuit comprising:
- an operational amplifier of which one of a pair of input terminals is connected to a circuit input terminal to which an input signal is supplied;
- a plurality of capacitors;
- a first switch connected between the other one of said pair of input terminals and an output terminal of said operational amplifier;
- a second switch of which one end is connected to the one of said pair of input terminals;
- a third switch connected between the other end of said second switch and said output terminal;
- a plurality of capacitor selection switches connected between the other end of said second switch and one ends of said plurality of capacitors respectively;
- a plurality of capacitor selection switches connected between the other one of said pair of input terminals and the other ends of said plurality of capacitors respectively;
- and
- switch controlling means for controlling each of said switches according to the voltage level of said input signal and having an offset voltage of said operational amplifier stored in one of said plurality of capacitors.
6 more elements
A controlling method of an amplifier circuit including an operational amplifier for amplifying an input signal and a plurality of capacitors, comprising:
- a first step for selecting one of said plurality of capacitors according to a voltage level of said input signal and having an offset voltage of said operational amplifier stored in the selected capacitor in a first term of one output period;
- and
- a second step for correcting the output of said operational amplifier by using said offset voltage stored in said selected capacitor in a second term of said one output period.
A driving circuit of a display apparatus comprising:
- gray scale level voltage generating means for generating a plurality of gray scale level voltages;
- a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting an input signal inputted via the output terminal of said gray scale level voltage generating means;
- selection means for, of output signals of the plurality of gray scale level output circuits, selecting a signal necessary for driving the display apparatus;
- and
- controlling means for controlling each of said plurality of gray scale level output circuits,
- wherein each of said plurality of gray scale level output circuits has storing means for storing in advance each of offset voltages generated in said operational amplifier according to the level of the gray scale level voltage of said input signal, and said controlling means controls each of said plurality of gray scale level output circuits to correct output of said operational amplifier by using said offset voltages stored in said storing means.
3 more elements
A driving circuit of a display apparatus comprising:
- gray scale level voltage generating means for generating a plurality of gray scale level voltages;
- a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting an input signal inputted via the output terminal of said gray scale level voltage generating means;
- and
- selection means for, of output signals of the plurality of gray scale level output circuits, selecting a signal necessary for driving the display apparatus,
- wherein one of a pair of input terminals of said operational amplifier is connected to a circuit input terminal of said gray scale level output circuit to which the input signal is supplied;
- and
- each of said plurality of gray scale level output circuits has a plurality of capacitors, a first switch connected between the other one of said pair of input terminals and the output terminal of said operational amplifier, a second switch of which one end is connected to the one of said pair of input terminals, a third switch connected between the other end of said second switch and said output terminal, a plurality of capacitor selection switches connected between the other end of said second switch and one ends of said plurality of capacitors respectively, a plurality of capacitor selection switches connected between the other one of said pair of input terminals and the other ends of said plurality of capacitors respectively;
- and
- switch controlling means for controlling said switches of each of said plurality of gray scale level output circuits to have an offset voltage of said operational amplifier stored in one of said plurality of capacitors according to the level of the gray scale level voltage of said input signal.
6 more elements
A driving circuit of a display apparatus comprising:
- gray scale level voltage generating means for generating a plurality of gray scale level voltages;
- a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting a gray scale level voltage inputted via the output terminal of said gray scale level voltage generating means and one capacitor;
- selection means for, of the gray scale level voltages outputted from the plurality of gray scale level output circuits, selecting a voltage necessary for driving the display apparatus;
- and
- controlling means for, in one output period, controlling each of said plurality of gray scale level output circuits to have an offset voltage generated in said operational amplifier due to said gray scale level voltage stored in said capacitor and correct output of said operational amplifier by using the stored offset voltage, and in each output period later than said one output period, controlling each of said plurality of gray scale level output circuits to correct the output of said operational amplifier by using said offset voltage stored in said capacitor in said one output period.
2 more elements
A driving circuit of a display apparatus comprising:
- gray scale level voltage generating means for generating a plurality of gray scale level voltages;
- a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting an input signal inputted via the output terminal of said gray scale level voltage generating means;
- and
- selection means for, of output signals of the plurality of gray scale level output circuits, selecting a signal necessary for driving the display apparatus,
- wherein one of a pair of input terminals of said operational amplifier is connected to a circuit input terminal of said gray scale level output circuit to which the input signal is supplied;
- and
- each of said plurality of gray scale level output circuits has two capacitors, a first switch connected between the other one of said pair of input terminals and the output terminal of said operational amplifier, a second switch of which one end is connected to the one of said pair of input terminals, a third switch connected between the other end of said second switch and said output terminal, two capacitor selection switches connected between the other end of said second switch and one ends of said two capacitors respectively, two capacitor selection switches connected between the other one of said pair of input terminals and the other ends of said two capacitors respectively;
- and
- switch controlling means for controlling said switches of each of said plurality of gray scale level output circuits to have an offset voltage of said operational amplifier stored in one of said two capacitors according to a polarity of the gray scale level voltage of said input signal.
6 more elements
A controlling method of a driving circuit of a display apparatus having gray scale level voltage generating means for generating a plurality of gray scale level voltages, a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting an input signal inputted via the output terminal of said gray scale level voltage generating means and a plurality of capacitors, and selection means for, of output signals of the plurality of gray scale level output circuits, selecting a signal necessary for driving the display apparatus, comprising:
- a first step for controlling each of said plurality of gray scale level output circuits to select one of said plurality of capacitors according to the level of the gray scale level voltage of said input signal and have an offset voltage of said operational amplifier stored in the selected capacitor in a first term of one output period;
- and
- a second step for controlling each of said plurality of gray scale level output circuits to correct the output of said operational amplifier by using said offset voltage stored in said selected capacitor in a second term of said one output period.
A controlling method of a driving circuit of a display apparatus comprising:
- gray scale level voltage generating means for generating a plurality of gray scale level voltages;
- a plurality of gray scale level output circuits, provided to a plurality of output terminals of the gray scale level voltage generating means respectively, each of them having an operational amplifier for impedance-converting an input signal inputted via the output terminal of said gray scale level voltage generating means;
- and
- selection means for, of output signals of the plurality of gray scale level output circuits, selecting a signal necessary for driving the display apparatus, and wherein:
- one of a pair of input terminals of said operational amplifier is connected to a circuit input terminal of said gray scale level output circuit to which an input signal is supplied;
- and each of said plurality of gray scale level output circuits has two capacitors, a first switch connected between the other one of said pair of input terminals and the output terminal of said operational amplifier, a second switch of which one end is connected to one of said pair of input terminals, a third switch connected between the other end of said second switch and said output terminal, two capacitor selection switches connected between the other end of said second switch and one ends of said two capacitors respectively, two capacitor selection switches connected between the other one of said pair of input terminals and the other ends of said two capacitors respectively, and including a step of controlling each of said switches of said plurality of gray scale level output circuits to have an offset voltage of said operational amplifier stored in one of said two capacitors according to a polarity of the gray scale level voltage of said input signal.
3 more elements
An amplifier circuit comprising:
- an operational amplifier of which non-inverting input terminal is connected to a circuit input terminal to which an input signal is supplied;
- a plurality of capacitors;
- a first switch of which one end is connected to said non-inverting input terminal;
- a second switch connected between the other end of said first switch and an output terminal of said operational amplifier;
- a plurality of capacitor selection switches connected between the other end of said first switch and one ends of said plurality of capacitors respectively;
- a plurality of switches connected between the plurality of inverting input terminals of said operational amplifier connected to the other ends of said plurality of capacitors respectively and the output terminal of said operational amplifier respectively;
- and
- switch controlling means for controlling each of said switches according to the voltage level of said input signal and having an offset voltage of said operational amplifier stored in one of said plurality of capacitors.
5 more elements
Dependencies are inferred from the claim text.