IP Library › Granted Patent US 7,348,947
Granted Patent B2
US 7,348,947 · App. 10/745,497 · Granted Mar 25, 2008

Circuit, display device, and electronic apparatus

Assignee: Semiconductor Energy Laboratory Co., Ltd.
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Quick Facts
Patent No.
US 7,348,947
App. No.
10/745,497
Filed
Dec 29, 2003
Granted
Mar 25, 2008
Kind
B2
Art Unit
2629
USPC
345/82
Abstract

A simple DA converter circuit which reads in digital voltage value data and outputs analog current value data is provided. The DA converter circuit according to the invention can be applied, for example, to a data driver circuit of an AM-OLED display device. The DA converter circuit comprises a current output circuit comprising a plurality of drive transistors. Gate electrodes of the transistors are electrically connected to each other, and a switch is provided between the gate electrode and drain electrode of each drive transistor.

Claims (26)

1. A current output circuit comprising:

first and second drive transistors, wherein gate electrodes of the first and second drive transistors are electrically connected to each other;

a first switch provided between the gate electrode and a drain electrode of the first drive transistor; and

a second switch provided between the gate electrode and a drain electrode of the second driver transistor.

2. A current output DA converter circuit comprising:

the current output circuit according to claim 1 ,

wherein a switch whose ON/OFF operation is controlled corresponding to bit data is provided at each drain of the drive transistors of the current output circuit.

3. A display device comprising the current output DA converter circuit according to claim 2 .

4. An electronic apparatus to which the current output DA converter circuit according to claim 2 is applied.

5. A current output DA converter circuit according to claim 2 , further comprising:

a first DA switch connected to the first drive transistor and the first switch; and

a second DA switch connected to the second drive transistor and the second switch.

6. A current output DA converter circuit comprising:

a plurality of current output circuits, one of which comprising:

a drive transistor,

wherein a switch is provided between a gate electrode and drain electrode of the drive transistor, and

other one of the current output circuits being the current output circuit according to claim 1 .

7. A display device comprising the current output DA converter circuit according to claim 6 .

8. An electronic apparatus to which the current output DA converter circuit according to claim 6 is applied.

9. A current output DA converter circuit according to claim 6 , further comprising:

a first DA switch connected to the first drive transistor and the first switch; and

a second DA switch connected to the second drive transistor and the second switch.

10. A display device comprising the current output circuit according to claim 1 .

11. An electronic apparatus comprising the display device according to claim 10 .

12. A current output circuit according to claim 1 , wherein the current output circuit is used in an electronic apparatus selected from the group consisting of a monitor, a notebook type personal computer, a mobile computer, a portable image reproduction device with a recording medium, a goggle type display, a video camera, and a mobile telephone.

13. A current output circuit according to claim 1 , wherein L/W size ratios of the first and second drive transistors are different from each other.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 29, 2003
From: INUKAI, KAZUTAKA
To: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
Reel/Frame 014855/0269 →
Priority Claims (1)
JP 2003-001495 · Jan 7, 2003 · national
Continuity (1)
Related Publication 20040135779A1 · Jul 15, 2004