Display drive integrated circuit and method for generating system clock signal

• US 7,898,539 B2
• Filed: 03/02/2007
• Issued: 03/01/2011
• Est. Priority Date: 03/03/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Chung, Kyu-young, Bae, Jong-kon
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): HARRIS, DOROTHY H
• Application Number:
  US11/712,968
• Publication Number:
  US 20070205971A1
• Time in Patent Office: 1,460 Days
• Field of Search: 345/99, 345/213
• US Class Current: 345/213
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

A display drive integrated circuit is for driving a display panel. The display drive integrated circuit includes a division rate output unit which outputs as a division rate corresponding to a quotient obtained by dividing by M a total number of clock cycles of a dot clock signal corresponding to a clock cycle of a horizontal synchronization signal, where M is a natural number, and a system clock generating unit which generates a system clock signal by dividing the dot clock signal using the division rate.

Claims

1. A display drive integrated circuit for driving a display panel, comprising:

a division rate output unit, comprising;

a counter which receives a dot clock signal and a horizontal synchronization signal from an external source via an interface, and which outputs a count value equaling a total number of clock cycles of the dot clock signal corresponding to one cycle of the horizontal synchronization signal, and

a division rate output device which receives the count value and outputs a division rate value corresponding to an integer portion of a quotient obtained by dividing the count value by M where M is a natural number greater than one; and

a system clock generating unit which receives the dot clock signal and the division rate value and in response thereto generates a system clock signal by dividing a frequency of the dot clock signal by a divisor obtained by multiplying the division rate value by a fixed value.

2. The display drive integrated circuit of claim 1, wherein M=2^K, where K is a natural number.

3. The display drive integrated circuit of claim 1, wherein the count value output by the counter has L bits, and wherein the division rate output device outputs L−

K bits as the division rate value by excluding lower K bits from the L bits output by the counter, where L and K are natural numbers, and K is less than L.

4. The display drive integrated circuit of any one of claims 2 and 3, wherein M=16 and K=4.

5. The display drive integrated circuit of claim 1, wherein, when the quotient obtained by dividing the count value by M is an odd number, the division rate output device outputs as the division rate value a value obtained by adding 1 to the quotient or subtracting 1 from the quotient, and when the quotient obtained by dividing the count value by M is an even number, the division rate output device outputs the quotient as the division rate value.

6. The display drive integrated circuit of claim 1, wherein, when the quotient obtained by dividing the count value by M is an even number, the division rate output device outputs as the division rate value a value obtained by adding 1 to the quotient or subtracting 1 from the quotient, and when the quotient obtained by dividing the count value by M is an odd number, the division rate output device outputs the quotient as the division rate value.

7. The display drive integrated circuit of claim 1, wherein the system clock generating unit generates system clock signals having various frequencies by dividing the frequency of the dot clock signal by an integral multiple of the division rate value.

8. The display drive integrated circuit of claim 1, wherein the horizontal synchronization signal has a constant frequency.

9. The display drive integrated circuit of claim 1, wherein the counter receives the dot clock signal and the horizontal synchronization signal via an RGB interface.

10. A method of generating a system clock signal for a display drive integrated circuit which drives a display panel, the method comprising:

receiving a dot clock signal and a horizontal synchronization signal from an external source via an interface;

counting a number of cycles of the dot clock signal corresponding to one cycle of the horizontal synchronization signal and outputting a count value equaling a total number of clock cycles of the dot clock signal corresponding to one cycle of the horizontal synchronization signal;

dividing the count value by M to produce a quotient, where M is a natural number;

outputting a division rate value corresponding to an integer portion of the quotient; and

generating the system clock signal by dividing a frequency of the dot clock signal by a divisor obtained by multiplying the division rate value by a fixed value.

11. The method of claim 10, wherein M=2^K, where K is a natural number.

12. The method of claim 10, wherein the count value has L bits, and wherein L−

K bits are output as the division rate value by excluding lower K bits from the L bits, where L and K are natural numbers, and K is less than L.

13. The method of any one of claims 11 and 12, wherein M=16 and K=4.

14. The method of claim 10, wherein, when the quotient obtained by dividing the count value by M is an odd number, the division rate value is output as a value obtained by adding 1 to the quotient or subtracting 1 from the quotient, and when the quotient obtained by dividing the count value by M is an even number, the quotient is output as the division rate value.

15. The method of claim 10, wherein, when the quotient obtained by dividing the count value by M is an even number, the division rate value is output as a value obtained by adding 1 to the quotient or subtracting 1 from the quotient, and when the quotient obtained by dividing the count value by M is an odd number, the quotient is output as the division rate value.

16. The method of claim 10, wherein the generating of the system clock signal comprises generating system clock signals having various frequencies by dividing the frequency of the dot clock signal using integral multiples of the division rate value.

17. The method of claim 10, wherein the horizontal synchronization signal has a constant frequency.

18. The method of claim 10, wherein receiving the dot clock signal and the horizontal synchronization signal comprises receiving the dot clock signal and the horizontal synchronization signal via an RGB interface.