Digital analog converter and electronic device using the same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsMunehiro Azami, Mitsuaki Osame, Yutaka Shionoiri, Shou Nagao
Life of this patent
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Abstract
The present invention relates to a D/A converter circuit which is capable of independently controlling the output voltage amplitude VOUT and the reference voltage. The D/A converter circuit converts “n” bit digital data (“n”: natural number) to analog signals, wherein the respective bits of said “n” bit digital data control a switch, control charge and discharge of electric charges in the capacitance connected to said switch, and output analog signals with the offset potential used as a reference potential.
Claims15
A D/A converter circuit comprising:
- a plurality of capacitors;
- an output terminal connected to the plurality of capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- a plurality of switches connected to the plurality of capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding capacitors.
A display device comprising a D/A converter circuit, the D/A converter circuit comprising:
- a plurality of capacitors;
- an output terminal connected to the plurality of capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- a plurality of switches connected to the plurality of capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding capacitors.
An electronic device comprising a D/A converter circuit comprising:
- a plurality of capacitors;
- an output terminal connected to the plurality of capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- a plurality of switches connected to the plurality of capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding capacitors.
A D/A converter circuit comprising:
- n capacitors wherein an i-th capacitor has a capacitance of 2i−1C where i is a natural number and C is a constant;
- an output terminal connected to the n capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- n switches connected to n capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding n capacitors.
An active matrix type liquid crystal display device comprising a D/A converter circuit comprising:
- a plurality of capacitors;
- an output terminal connected to the plurality of capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- a plurality of switches connected to the plurality of capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding capacitors.
An active matrix type EL display device comprising a D/A converter circuit comprising:
- a plurality of capacitors;
- an output terminal connected to the plurality of capacitors;
- an offset power source connected to the output terminal through a reset switch;
- a first voltage source and a second voltage source;
- a plurality of switches connected to the plurality of capacitors, respectively, to selectively connect one of the first and the second voltage sources to the corresponding capacitors.
Dependencies are inferred from the claim text.