Controller and driving method for power circuits, electrical circuit for supplying energy and display device having the electrical circuit

• US 20040178781A1
• Filed: 01/13/2004
• Published: 09/16/2004
• Est. Priority Date: 01/22/2003
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Lin, Yung-Lin
• Granted Patent: US 7,200,017 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A controller for controlling at least two power circuits comprises a phase-shift selector for generating a reference signal according to variable input signals, the reference signal is programmed to indicate an amount of phase-delay according to a number of CCFL power circuits connected; and a pulse generator for receiving the reference signal and generating a pulse signal CLK in response to the received reference signal, the pulse signal is coupled to the CCFL power circuits connected for initiating the operation of the CCFL power circuits. The controller is used to control energy supplying to an electrical circuit comprising multiple CCFL power circuits and is more particularly to provide phase delay to the electrical circuit. Usually, the electrical circuit is applied to display devices, such as liquid crystal display monitors, liquid crystal display computers and liquid crystal display televisions.

Claims

1. A controller for controlling at least two cold cathode fluorescent lamp (CCFL) power circuits, comprising

a phase-shift selector for generating a reference signal, the reference signal being programmed to indicate an amount of phase-delay according to a number of CCFL power circuits connected;

and

a pulse generator for receiving the reference signal and generating a pulse signal in response to the received reference signal, the pulse signal being coupled to the at least two CCFL power circuits for initiating the operation of the at least two CCFL power circuits.

2. The controller of claim 1, wherein the phase-shift selector comprises at least one input terminal for programming the number of CCFL power circuits connected and an output for outputting the reference signal according to an input signal coupled to the at least one input terminal.

3. The controller of claim 2, wherein the input signal is an analog signal for selecting a number of phases or a digital signal for selecting a number of phases.

4. An electrical circuit for supplying energy to CCFL loads, comprising

at least two CCFL power circuits, each of the at least two CCFL power circuits comprising a phase-delay selector for programming a phase-delay of the CCFL power circuit, wherein the amount of the phase-delay for each CCFL power circuit is stepwise increased according to operation sequence of the CCFL power circuits;

and

a controller having a phase-shift selector for generating a reference signal according to a number of the CCFL power circuits connected and a pulse generator for receiving the reference signal and generating a pulse signal in response to the received reference signal, the pulse signal being coupled to the at least two CCFL power circuits for initiating the operation of the at least two CCFL power circuits;

wherein a first CCFL power circuit of the at least two CCFL power circuits is initiated immediately after the pulse signal is received and a second CCFL power circuit of the at least two CCFL power circuits is initiated after a predetermined amount of phase-delay.

5. The electrical circuit of claim 4, wherein the phase-shift selector comprises at least one input terminal for programming the number of CCFL power circuits connected and an output for outputting the reference signal according to an input signal coupled to the at least one input terminal.

6. The electrical circuit of claim 5, wherein the input signal is an analog signal for selecting a number of phases or a digital signal for selecting a is number of phases.

7. The electrical circuit of claim 4, further comprising transformers.

8. The electrical circuit of claim 7, further comprising CCFL loads.

9. The electrical circuit of claim 4, wherein the CCFL power circuit further comprises a ramp generator for generating the phase-delay, and an initial point of the ramp generator occurs based on the pulse signal.

10. The electrical circuit of claim 4, wherein the CCFL power circuit further comprises a delay circuit for generating the programmed phase-delay.

11. A display device having CCFL loads, comprising

at least two CCFL power circuits, each of the at least two CCFL power circuits comprising a phase-delay selector for programming a phase-delay of the CCFL power circuit, wherein the amount of the phase-delay for each CCFL power circuit is stepwise increased according to operation sequence of the CCFL power circuits;

a controller having a phase-shift selector for generating a reference signal according to a number of the CCFL power circuits connected and a pulse generator for receiving the reference signal and generating a pulse signal in response the received reference signal, the pulse signal being coupled to the at least two CCFL power circuits for initiating the operation of the at least two CCFL power circuits;

at least two transformers, each coupled to the at least two CCFL power circuits, respectively;

at least two CCFL loads, each coupled to the at least two transformers, respectively;

a display panel;

wherein a first CCFL power circuit of the at least two CCFL power circuits is initiated immediately after the pulse signal is received so as to turn on a first CCFL load of the at least two CCFL loads and a second CCFL power circuit of the at least two CCFL power circuits is initiated after a predetermined amount of phase-delay so as to turn on a second CCFL load of the at least two CCFL loads.

12. The display device of claim 11, wherein the display device is a liquid crystal display television, liquid crystal display monitor or a liquid crystal display computer.

13. The display device of claim 11, wherein the phase-shift selector comprises at least one input terminal for programming the number of CCFL power circuits connected and an output for outputting the reference signal according to an input signal coupled to the at least one input terminal.

14. The display device of claim 13, wherein the input signal is an analog signal for selecting a number of phases or a digital signal for selecting a number of phases.

15. The display device of claim 11, wherein the CCFL power circuit further comprises a ramp generator for generating the phase-delay, and an initial point of the ramp generator occurs based on the pulse signal.

16. The display device of claim 11, wherein the CCFL power circuit further comprises a delay circuit for generating the programmed phase-delay.

17. A method for driving at least two CCFL power circuits, comprising the steps of

(a) generating a reference signal from the phase-shift selector;

(b) coupling the reference signal to a pulse generator;

(c) generating a pulse signal from the pulse generator in response to the reference signal and coupling the pulse signal to each of the at least two CCFL power circuits;

(d) initiating the operation of a first CCFL power circuit after receiving the pulse signal; and

(e) initiating the operation of a second CCFL power circuit after a predetermined amount of phase-delay.

18. The method of claim 17, wherein the reference signal in the step (a) is generated according to input signals coupled to the phase-shift selector.

19. The method of claim 17, wherein the step (d) further comprises the step of coupling the first CCFL power circuit to a first transformer.

20. The method of claim 19, further comprising the step of coupling the first transformer to a first CCFL load.

21. The method of claim 17, wherein the step (e) further comprises the step of coupling the second CCFL power circuit to a second transformer.

22. The method of claim 21, further comprising the step of coupling the second transformer to a second CCFL load.

23. The method of claim 17, wherein the phase-delay in the step (e) is generated by a ramp generator, and an initial point of the ramp generator occurs based on the pulse signal.

24. The method of claim 17, wherein the phase-delay in the step (e) is generated by a delay circuit, and an amount of the phase-delay is programmed by a phase-delay selector in the CCFL power circuit.