Emission driver and electroluminescent display including such an emission driver

• US 7,880,694 B2
• Filed: 08/29/2007
• Issued: 02/01/2011
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Chung, Bo-yong
• Primary Examiner(s): Tran; Henry N
• Application Number:
  US11/896,025
• Publication Number:
  US 20080055208A1
• Time in Patent Office: 1,252 Days
• Field of Search: 345 76- 82, 345/206, 345211-214, 345/690, 315161-164, 315/169.3, 315/170, 315195-199, 315/299, 327/387, 327/389, 327/390, 327/391
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G11C 19/184 with field-effect transistors, e.g. MOS-FET

Abstract

An emission driver may include a first signal processor adapted to receive a clock signal, an input signal and an inverse input signal, and generate a first output signal, a second signal processor adapted to receive the first output signal, an inverse clock signal and negative feedback signals, and generate a second output signal, a third signal processor adapted to receive the second output signal and the input signal, and generate a third output signal that is an inverse of the second output signal based on the input signal, a fourth signal processor adapted to receive the second output signal, and generate a fourth output signal based on the second output signal, the fourth output signal being an inverse signal of the third output signal, and a fifth signal processor adapted to receive the fourth output signal and output a fifth output signal based on a stored predetermined voltage.

Claims

1. An emission driver, comprising:

a first signal processor adapted to receive a clock signal, an input signal and an inverse input signal, and to generate a first output signal;

a second signal processor adapted to receive the first output signal, an inverse clock signal and negative feedback signals, and to generate a second output signal;

a third signal processor adapted to receive the second output signal and the input signal, and to generate a third output signal that is an inverse of the second output signal based on the input signal;

a fourth signal processor adapted to receive the second output signal, and to generate a fourth output signal based on the second output signal, the fourth output signal being an inverse signal of the third output signal; and

a fifth signal processor adapted to receive the fourth output signal, and to output a fifth output signal based on a stored predetermined voltage, the fifth output signal being an inverse of the fourth output signal,

wherein the negative feedback signals include the third output signal and the fourth output signal.

2. The emission driver as claimed in claim 1, wherein the first output signal corresponds to the inverse input signal delayed for a predetermined period of time.

3. The emission driver as claimed in claim 1, wherein the second output signal corresponds to the first output signal corrected based on at least one of the negative feedback signals.

4. The emission driver as claimed in claim 1, wherein the fifth signal processor comprises a plurality of transistors, and the predetermined voltage is at least a threshold voltage of one of the plurality of transistors arranged between an output terminal of the emission driver from which the fifth output signal is supplied and a ground power source such that when the fifth output signal is at a low level, a voltage thereof is a voltage of the ground power source.

5. The emission driver as claimed in claim 1, wherein the first signal processor comprises:

a first transistor adapted to control a supply of a driving source voltage corresponding to a driving power source based on the clock signal;

a second transistor adapted to control the supply of the driving power source voltage supplied through the first transistor to a first node based on the input signal;

a third transistor adapted to control current flow from the first node to a ground power source based on a voltage of a gate electrode thereof;

a fourth transistor coupled between a source electrode and the gate electrode of the third transistor, and adapted to control a voltage between the source electrode and the gate electrode of the third transistor based on the input signal;

a fifth transistor adapted to control a voltage of the gate electrode of the third transistor based on the inverse input signal;

a sixth transistor coupled between the third transistor and the ground power source, and adapted to perform a switching operation based on the clock signal; and

a first capacitor adapted to store a voltage corresponding to the gate electrode of the third transistor.

6. The emission driver as claimed in claim 1, wherein the second signal processor comprises:

a seventh transistor coupled to a driving power source and adapted to perform a switching operation based on the inverse clock signal;

an eighth transistor adapted to perform a switching operation based on the third output signal to transfer a driving source voltage corresponding to the driving power source supplied through the seventh transistor to a first node;

a ninth transistor adapted to allow current to flow from a second node to a ground power source based on a voltage applied to a gate electrode thereof;

a tenth transistor coupled between a source electrode and the gate electrode of the ninth transistor, and adapted to perform a switching operation based on the input signal to control a voltage between the source and the gate terminals of the ninth transistor;

an eleventh transistor adapted to control the voltage of the gate electrode of the ninth transistor based on the fourth output signal;

a twelfth transistor adapted to perform a switching operation based on the inverse clock signal to allow current to flow between the ninth transistor and the ground power source; and

a second capacitor adapted to store the voltage of the gate electrode of the ninth transistor.

7. The emission driver as claimed in claim 1, wherein the third signal processor comprises:

a thirteenth transistor adapted to perform a switching operation based on the second output signal to allow a voltage of a driving power source to be supplied to a third node; and

a fourteenth transistor adapted to perform a switching operation based on the input signal to allow current to flow from the third node to a ground power source.

8. The emission driver as claimed in claim 1, wherein the fourth signal processor comprises:

a fifteenth transistor adapted to perform a switching operation based on the third output signal to allow a voltage of a driving power source to be supplied to a fourth node; and

a sixteenth transistor adapted to perform a switching operation based on the second output signal to allow current to flow from the fourth node to a ground power source.

9. The emission driver as claimed in claim 1, wherein the fifth signal processor comprises:

a seventeenth transistor adapted to perform a switching operation based on the fourth output signal to supply a voltage corresponding to a driving power source to an output terminal of the emission driver;

an eighteenth transistor adapted to perform a switching operation based on the third output signal to allow current to flow from the output terminal to a ground power source; and

a third capacitor adapted to store the predetermined voltage such that when the eighteenth transistor is in an on state and the seventeenth transistor is in an off state, a voltage of the output terminal is a voltage of the ground power source based on the predetermined voltage stored in the capacitor.

10. The emission driver as claimed in claim 1, wherein the first, second, third, fourth and fifth signal processors include a plurality of transistors and the plurality of transistors are all one of p-type transistors and n-type transistors, such that the first, second, third, fourth and fifth signal processors all include the same type of transistors.

11. An electroluminescent display, comprising:

a pixel unit adapted to display an image based on at least one pixel formed in a region defined by a data line, a scan line and an emission control line;

a data driver adapted to transfer a data signal to the data line;

a scan driver adapted to transfer a scan signal to the scan line; and

an emission driver adapted to transfer an emission control signal to the emission control line, wherein the emission driver includes;

a first signal processor adapted to receive a clock signal, an input signal and an inverse input signal, and to generate a first output signal;

a second signal processor adapted to receive the first output signal, an inverse clock signal and negative feedback signals, and to generate a second output signal;

a third signal processor adapted to receive the second output signal and the input signal, and to generate a third output signal that is an inverse of the second output signal based on the input signal;

a fourth signal processor adapted to receive the second output signal, and to generate a fourth output signal based on the second output signal, the fourth output signal being an inverse signal of the third output signal; and

a fifth signal processor adapted to receive the fourth output signal, and to output a fifth output signal based on a stored predetermined voltage, the fifth output signal being an inverse of the fourth output signal,

wherein the negative feedback signals include the third output signal and the fourth output signal.

12. The electroluminescent display as claimed in claim 11, wherein the first output signal corresponds to the inverse input signal delayed for a predetermined period of time.

13. The electroluminescent display as claimed in claim 11, wherein the second output signal corresponds to the first output signal corrected based on at least one of the negative feedback signals.

14. The electroluminescent display as claimed in claim 11, wherein the first signal processor includes:

a first transistor adapted to control a supply of a driving source voltage corresponding to a driving power source based on the clock signal;

a second transistor adapted to control the supply of the driving power source voltage supplied through the first transistor to a first node based on the input signal;

a third transistor adapted to control current flow from a first node to a ground power source based on a voltage of a gate electrode thereof;

a fourth transistor coupled between a source electrode and the gate electrode of the third transistor, and adapted to control a voltage between the source electrode and the gate electrode of the third transistor based on the input signal;

a fifth transistor adapted to control a voltage of the gate electrode of the third transistor based on the inverse input signal;

a sixth transistor coupled between the third transistor and the ground power source, and adapted to perform a switching operation based on the clock signal; and

a first capacitor adapted to store a voltage corresponding to the gate electrode of the third transistor.

15. The electroluminescent display as claimed in claim 11, wherein the second signal processor includes:

a seventh transistor coupled to a driving power source and adapted to perform a switching operation based on the inverse clock signal;

an eighth transistor adapted to perform a switching operation based on the third output signal to transfer a driving source voltage corresponding to the driving power source supplied through the seventh transistor to a first node;

a ninth transistor adapted to allow current to flow from a second node to a ground power source based on a voltage applied to a gate electrode thereof;

a tenth transistor coupled between a source electrode and the gate electrode of the ninth transistor, and adapted to perform a switching operation based on the input signal to control a voltage between the source and the gate terminals of the ninth transistor;

an eleventh transistor adapted to control the voltage of the gate electrode of the ninth transistor based on the fourth output signal;

a twelfth transistor adapted to perform a switching operation based on the inverse clock signal to allow current to flow between the ninth transistor and the ground power source; and

a second capacitor adapted to store the voltage of the gate electrode of the ninth transistor.

16. The electroluminescent display as claimed in claim 11, wherein the third signal processor includes:

a thirteenth transistor adapted to perform a switching operation based on the second output signal to allow a voltage of a driving power source to be supplied to a third node; and

a fourteenth transistor adapted to perform a switching operation based on the input signal to allow current to flow from the third node to a ground power source.

17. The electroluminescent display as claimed in claim 11, wherein the fourth signal processor includes:

a fifteenth transistor adapted to perform a switching operation based on the third output signal to allow a voltage of a driving power source to be supplied to a fourth node; and

a sixteenth transistor adapted to perform a switching operation based on the second output signal to allow current to flow from the fourth node to a ground power source.

18. The electroluminescent display as claimed in claim 11, wherein the fifth signal processor includes:

a seventeenth transistor adapted to perform a switching operation based on the fourth output signal to supply a voltage corresponding to a driving power source to an output terminal of the emission driver;

an eighteenth transistor adapted to perform a switching operation based on the third output signal to allow current to flow from the output terminal to a ground power source; and

a third capacitor adapted to store the predetermined voltage such that when the eighteenth transistor is in an on state and the seventeenth transistor is in an off state, a voltage of the output terminal is a voltage of the ground power source based on the predetermined voltage stored in the capacitor.

19. The electroluminescent display as claimed in claim 11, wherein the first, second, third, fourth and fifth signal processors include a plurality of transistors and the plurality of transistors are all one of p-type transistors and n-type transistors such that the first, second, third, fourth and fifth signal processors all include the same type of transistors.

20. The electroluminescent display as claimed in claim 11, wherein the electroluminescent display is an organic electroluminescent display.