Supply of a programming current to a pixel
A data line drive circuit is equipped with a single line driver 300 and a gate voltage generation circuit 400 . The single line driver 300 is constructed such that N groups (where N is an integer 2 or larger) of series connections of drive transistors 21 to 28 and switching transistors 81 to 88 are connected in parallel. The gate voltage generation circuit 400 includes two transistors 71 and 72 constituting a current mirror circuit, a drive transistor 73, and a constant voltage generation transistor 31. The range of an output current I out can be controlled by changing any of the design values of the parameters including: relative values K a and K b of the gain coefficient for the transistors 31 and 32, the source voltage VDREF of the gate voltage generation circuit 400, and the gate signal VRIN of the drive transistor 73.
1. An electro-optical device comprising:
a pixel matrix in which pixels each including a luminescent element are arrayed in the form a matrix;
a plurality of scan lines each connected to a pixel group arrayed in a row direction of the pixel matrix;
a plurality of data lines each connected to a pixel group arrayed in a column direction of the pixel matrix;
a scan line drive circuit, connected to the plurality of scan lines, for selecting one row in the pixel matrix; and
a data line drive circuit for generating a data signal having a current value corresponding to a level of light to be emitted by the luminescent element, and outputting the data signal to at least one of the plurality of data lines;
wherein the data line drive circuit comprises:
a current-addition type current generation circuit having a structure where N series connections of a first drive transistor for generating a prescribed current and a first switching transistor whose on/off switching is controlled in response to a control signal supplied by an external circuit are connected mutually in parallel, where N is an integer of 2 or greater; and
a control-electrode signal generation circuit for generating a control-electrode signal having a prescribed signal level and supplying the control-electrode signal commonly to control electrodes of N number of first drive transistors.
2. An electro-optical device of claim 1 , wherein the control-electrode signal generation circuit includes:
a control-electrode signal generation transistor having a first control electrode for generating the control-electrode signal at the first control electrode; and
a constant current circuit for generating a constant current flowing in the control-electrode signal generation transistor,
and wherein the first control electrode of the control-electrode signal generation transistor and the control electrodes of the N number of first drive transistors of the current generation circuit are mutually connected.
3. An electro-optical device according to claim 2 , wherein the constant current circuit includes:
a current mirror circuit, having two transistors connected respectively to a first and a second wire, for generating a current on the second wire proportional to a current on the first wire; and
a second drive transistor, connected to the first wire, for generating a prescribed current on the first wire in response to a control signal provided by an external circuit,
and wherein the control-electrode signal generation transistor is connected to the second wire.
4. An electronic device comprising the electro-optical device according to claim 3 .
5. An electro-optical device according to claim 2 , wherein the current generation circuit further includes:
a third drive transistor, coupled in parallel with the N series connections of the first drive transistor and the first switching transistor, for generating an offset current,
and wherein a control electrode of the third drive transistor is connected to the first control electrode of the control-electrode signal generation transistor without a switching transistor being provided between the third drive transistor and the data line.
6. An electronic device comprising the electro-optical device according to claim 5 .
7. An electronic device comprising the electro-optical device according to claim 2 .
8. An electro-optical device according to claim 1 , wherein the pixel matrix is driven using an active matrix driving technique.
9. An electronic device comprising the electro-optical device according to claim 8 .
10. An electro-optical device according to claim 1 , wherein the pixel matrix is driven using a passive matrix driving technique.
11. An electronic device comprising the electro-optical device according to claim 10 .
12. An electro-optical device according to claim 1 , wherein the N number of first drive transistors are constructed such that a relative values of a gain coefficient for a nth transistor in the N number of first drive transistors is 2n−1, where n is an integer between 1 and N.
13. An electronic device comprising the electro-optical device according to claim 12 .
14. An electro-optical device according to claim 1 , wherein each series connection between the first drive transistor and the first switching transistor includes a resistor element.
15. An electro-optical device according to claim 14 , wherein the resistor element is a transistor.
16. An electronic device comprising the electro-optical device according to claim 15 .
17. An electronic device comprising the electro-optical device according to claim 14 .
18. An electronic device comprising the electro-optical device according to claim 1 .
19. A data line drive circuit for generating a data signal having a current value corresponding to a light emission level of a luminescent element, and outputting the data signal on a data line connected to an pixel including the luminescent element, the data line drive circuit comprising:
a current-addition type current generation circuit having a structure where N series connections of a first drive transistor for generating a prescribed current and a first switching transistor whose on/off switching is controlled in response to a control signal supplied by an external circuit are connected mutually in parallel, where N is an integer of 2 or greater; and
a control-electrode signal generation circuit for generating a control-electrode signal having a prescribed signal level and supplying the control-electrode signal commonly to control electrodes of N number of first drive transistors.
20. A data line drive circuit according to claim 19 , wherein the control-electrode signal generation circuit includes:
a control-electrode signal generation transistor having a first control electrode for generating the control-electrode signal at the first control electrode; and
a constant current circuit for generating a constant current flowing in the control-electrode signal generation transistor,
and wherein the first control electrode of the control-electrode signal generation transistor and the control electrodes of the N number of first drive transistors of the current generation circuit are mutually connected.
21. A data line drive circuit according to claim 20 , wherein the current generation circuit further includes:
a third drive transistor, coupled in parallel with the N series connections of the first drive transistor and the first switching transistor, for generating an offset current,
and wherein a control electrode of the third drive transistor is connected to the first control electrode of the control-electrode signal generation transistor without a switching transistor being provided between the third drive transistor and the data line.
22. A data line drive circuit according to claim 19 , wherein the constant current circuit includes:
a current mirror circuit, having two transistors connected respectively to a first and a second wire, for generating a current on the second wire proportional to a current on the first wire; and
a second drive transistor, connected to the first wire, for generating a prescribed current on the first wire in response to a control signal provided by an external circuit,
and wherein the control-electrode signal generation transistor is connected to the second wire.
23. A data line drive circuit according to claim 19 , wherein each series connection between the first drive transistor and the first switching transistor includes a resistor element.
24. A data line drive circuit according to claim 23 , wherein the resistor element is a transistor.
25. A data line drive circuit according to claim 19 , wherein the N number of first drive transistors are constructed such that a relative values of a gain coefficient for a nth transistor in the N number of first drive transistors is 2n−1, where n is an integer between 1 and N.
26. A data line drive circuit according to claim 19 , wherein the pixel matrix is driven using an active matrix driving technique.
27. A data line drive circuit according to claim 19 , wherein the pixel matrix is driven using a passive matrix driving technique.