Driver system and method for a field emission device

• US 6,300,922 B1
• Filed: 01/04/1999
• Issued: 10/09/2001
• Est. Priority Date: 01/05/1998
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Teggatz, Ross E.
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): KUMAR, SRILAKSHMI K
• Application Number:
  US09/224,978
• Time in Patent Office: 1,009 Days
• Field of Search: 345/74.1, 345/147, 345/75.2, 345/84, 345/55, 345/67, 345/60, 315/169.1, 315/148
• US Class Current: 345/75.2
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/22 using controlled light sources

Abstract

A field emission device (10) for reducing the power dissipation of an array (14) includes video controller (12) coupled to array (14) by memory (13), column drivers (16), row drivers (20), and anode power supply (22). Column drivers (16) includes PWM circuit (17) coupled to signal conditioner (18). Signal conditioner (18) receives input digital signal (24) from PWM circuit (17) and generates output digital signal (26) that reduces the frequency of state transitions of signal (24) while maintaining the same duty cycle as that of signal (24). This reduces the power dissipation of parasitic capacitances (36) associated with array (14) pursuant to the equation P=½CV²f.

Claims

1. A system for reducing the power dissipation of a load comprising:

a driver circuit;

a signal conditioner coupled to the driver circuit and operable to receive an input signal and generate an output signal having a series of frames, wherein each frame comprises a selected one of a corresponding frame of the input signal in forward order and a corresponding frame of the input signal in reverse order, in response to the state of a last time segment of a preceding frame of the output signal; and

a capacitively loaded device coupled to the signal conditioner and operable to receive the output signal.

2. The system of claim 1, further comprising:

a memory coupled to the driver circuit; and

a second driver circuit coupled to the memory.

3. The system of claim 1, wherein the driver circuit comprises a pulse width modulating circuit.

4. The system of claim 1, wherein the signal conditioner further comprises a logic unit operable to generate a frame of the output signal having a plurality of time segments, and wherein:

the state of a first time segment of the frame of the output signal comprises the state of the last time segment of the preceding frame of the output signal; and

the frame of the output signal has a substantially equal amount of low state and high state time segments as a corresponding frame of the input signal.

5. The system of claim 1, wherein the signal conditioner further comprises:

a bidirectional register operable to receive the input signal; and

a multiplexer coupled to the bidirectional register, the multiplexer operable to generate a frame of the output signal having a first section of one or more low state time segments and a second section of one or more high state time segments, wherein the multiplexer orders the first section and the second section in response to the state of the last time segment of the preceding frame of the output signal.

6. The system of claim 1, wherein the capacitively loaded device comprises a flat panel display.

7. The system of claim 1, wherein the capacitively loaded device comprises a field emission device array having a plurality of columns and a plurality of rows, and wherein an interface between each column and each row defines a pixel.

8. The system of claim 7, wherein the signal conditioner provides the output signal to a selected column of the field emission device array.

9. A method for reducing the power dissipation of a load, comprising:

receiving an input signal;

generating an output signal having a series of frames, wherein each frame comprises a selected one of a corresponding frame of the input signal in forward order and a corresponding frame of the input signal in reverse order, in response to the state of a last time segment of a preceding frame of the output signal; and

receiving the output signal at a field emission device array.

10. The method of claim 9, further comprising generating an input signal at a pulse width modulating circuit prior to the step of receiving the input signal, wherein the input signal comprises a series of frames, and wherein each frame comprises a plurality of time segments.

11. The method of claim 9, wherein the step of generating an output signal comprises:

receiving the state of the last time segment of the preceding frame of the output signal;

generating a frame of the output signal having a first section of one or more low state time segments, and a second section of one or more high state time segments; and

ordering the first section and the second section in response to the state of the last time segment of the preceding frame of the output signal.

12. The method of claim 9, wherein the step of generating an output signal comprises:

receiving the state of the last time segment of a preceding frame of the output signal; and

generating a frame of the output signal wherein the state of a first time segment of the frame of the output signal comprises the state of the last time segment of the preceding frame of the output signal and the frame of the output signal has a substantially equal amount of low state and high state time segments as a corresponding frame of the input signal.

13. The method of claim 9, wherein the field emission device array comprises a plurality of columns and a plurality of rows, wherein an interface between each column and each row defines a pixel.

14. The method of claim 13, further comprising providing the output signal to a selected column of the field emission device array.

15. A system for reducing the power dissipation of a field emission device, comprising:

a memory;

a driver circuit coupled to the memory and operable to generate an input signal;

a signal conditioner coupled to the driver circuit, and operable to receive the input signal and generate an output signal having a series of frames, wherein each frame comprises a plurality of time segments, and wherein;

the state of a first time segment of each frame of the output signal comprises the state of a last time segment of a preceding frame of the output signal; and

each frame of the output signal has a substantially equal amount of low state and high state time segments as a corresponding frame of the input signal; and

a field emission device array coupled to the signal conditioner and operable to receive the output signal.

16. The system of claim 15, wherein the driver circuit comprises a pulse width modulating circuit.

17. The system of claim 15, wherein the signal conditioner further comprises:

a bidirectional register operable to receive a frame of the input signal; and

a multiplexer coupled to the bidirectional register, the multiplexer operable to generate a corresponding frame of the output signal comprising a selected one of the corresponding frame of the input signal in forward order and the corresponding frame of the input signal in reverse order, in response to the state of the last time segment of the preceding frame of the output signal.

18. The system of claim 15, wherein the signal conditioner further comprises a logic unit operable to generate a frame of the output signal having a first section of one or more low state time segments and a second section of one or more high state time segments, wherein the logic unit orders the first section and the second section in response to the state of the last time segment of the preceding frame of the output signal.

19. The system of claim 15, wherein the field emission device array comprises a plurality of columns and a plurality of rows, and wherein an interface between each column and each row defines a pixel.

20. The system of claim 19, wherein the signal conditioner provides the output signal to a selected column of the field emission device array.