FRAME MAINTAINING CIRCUIT AND FRAME MAINTAINING METHOD

• US 20120242644A1
• Filed: 06/08/2012
• Published: 09/27/2012
• Est. Priority Date: 09/02/2010
• Status: Active Grant

• Current Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Original Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Inventors: Yen, Chih-Jen, LIU, Yueh-Hsiu, Li, Hsun-Yih, Hsu, Chih-Yung, Liu, Yu -Shau
• Granted Patent: US 8,907,939 B2
• Time in Patent Office: Days
• US Class Current: 345/212
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2096 Details of the interface to the display terminal specific for a flat panel suitable for both CRT and flat panel G09G5/006; specific for a CRT G09G1/167
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 5/008 Clock recovery

Abstract

A frame maintaining circuit including a detection circuit and a display control circuit is provided. The detection circuit detects an unusual status to output a status feedback signal. The display control circuit maintains a frame displayed by a display apparatus according to the status feedback signal until the unusual status ceases.

Claims

1. A frame maintaining circuit applied to a display apparatus, comprising:

a detection circuit, for detecting an unusual status to output a status feedback signal; and

a display control circuit, for maintaining a frame displayed by the display apparatus according to the status feedback signal until the unusual status ceases.

2. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a backlight module, and the display control circuit controls a backlight brightness generated by the backlight module to be same as the backlight brightness before an occurrence of the unusual status according to the status feedback signal.

3. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a power management unit, and the display control circuit controls a common voltage generated by the power management unit to be same as the common voltage before an occurrence of the unusual status according to the status feedback signal.

4. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a scan driver, the scan driver outputs a plurality of scan signals, and the display control circuit controls the scan driver to stop outputting the scan signals according to the status feedback signal.

5. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a data driver, the data driver outputs a plurality of data signals, and the display control circuit controls the data driver to stop outputting the data signals according to the status feedback signal.

6. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a timing controller and a scan driver, the scan driver outputs a plurality of scan signals, and the display control circuit controls the timing controller to change a first output enabling signal to a second output enabling signal according to the status feedback signal to mask the corresponding scan signal.

7. The frame maintaining circuit according to claim 1, wherein the display apparatus comprises a timing controller, a data driver and a scan driver, and the display control circuit controls the timing controller to mask or stop outputting signals to the data driver and the scan driver according to the status feedback signal.

8. The frame maintaining circuit according to claim 7, wherein after the unusual status is eliminated, the display control circuit controls the timing controller to first synchronize the signals to be outputted to the data driver and the scan driver and then output the synchronized signals to the data driver and the scan driver.

9. The frame maintaining circuit according to claim 1, wherein the detection circuit comprises:

a latch;

a switch, coupled to the latch;

a comparator, for providing a reset a signal to the latch; and

a switch control circuit, coupled to the switch, for controlling the switch to write a ground voltage to the latch to output the feedback signal in an occurrence of the unusual status.

10. The frame maintaining circuit according to claim 9, wherein the switch control circuit comprises:

a charging circuit, for providing a charging voltage according to a ground voltage and a supply voltage, the supply voltage being greater than the ground voltage; and

a phase inverter, for outputting an inversed signal to a control terminal of the switch according to the charging voltage.

11. The frame maintaining circuit according to claim 10, wherein the comparator outputs the reset signal according to the charging voltage and the supply voltage.

12. The frame maintaining circuit according to claim 10, wherein the charging circuit comprises:

a resistor, having a first terminal for receiving the supply voltage; and

a capacitor, having a first terminal coupled to a second terminal of the resistor; and

the phase inverter has an input terminal coupled to the first terminal of the capacitor and the second terminal of the resistor, and an output terminal coupled to the control terminal of the switch.

13. The frame maintaining circuit according to claim 10, wherein the reset signal is at a high potential when a difference between the supply voltage and the charging voltage is smaller than a threshold, and is at a low potential when the difference between the supply voltage and the charging voltage is not smaller than the threshold.

14. The frame maintaining circuit according to claim 1, wherein the detection circuit comprises:

a voltage-dividing circuit, for generating a first divided voltage and a second divided voltage according to the ground voltage and the supply voltage; and

a Schmitt trigger, for outputting the status feedback signal when a difference between the first divided voltage and the second divided voltage is greater than a threshold voltage.

15. The frame maintaining circuit according to claim 14, wherein the voltage-dividing circuit comprises:

a first resistor;

a second resistor, coupled to the first resistor in series, for providing the first divided voltage;

a capacitor;

a third resistor; and

a fourth resistor, coupled to the capacitor in parallel and coupled to the third resistor in series to provide the second divided voltage.

16. A frame maintaining method applied to a display apparatus, comprising:

detecting an unusual status to output a status feedback signal; and

maintaining a frame displayed by the display apparatus according to the status feedback signal until the unusual status ceases.

17. The frame maintaining method according to claim 16, wherein the display apparatus comprises a backlight module, and the maintaining step controls a backlight brightness generated by the backlight module to be same as the backlight brightness before an occurrence of the unusual status according to the status feedback signal.

18. The frame maintaining method according to claim 16, wherein the display apparatus comprises a power management unit, and the maintaining step controls a common voltage generated by the power management unit to be same as the common voltage before an occurrence of the unusual status according to the status feedback signal.

19. The frame maintaining method according to claim 16, wherein the display apparatus comprises a scan driver, the scan driver outputs a plurality of scan signals, and the maintaining step controls the scan driver to stop outputting the scan signals according to the status feedback signal.

20. The frame maintaining method according to claim 16, wherein the display apparatus comprises a data driver, the data driver outputs a plurality of data signals, and the maintaining step controls the data driver to stop outputting the data signals according to the status feedback signal.

21. The frame maintaining method according to claim 16, wherein the display apparatus comprises a timing controller and a scan driver, the scan driver outputs a plurality of scan signals, and the maintaining step controls the timing controller to change a first output enabling signal to a second output enabling signal according to the status feedback signal to mask the corresponding scan signal.

22. The frame maintaining method according to claim 16, wherein the display apparatus comprises a timing controller, a data driver and a scan driver, and the maintaining step controls the timing controller to mask or stop outputting signals to the data driver and the scan driver according to the status feedback signal.

23. The frame maintaining method according to claim 22, wherein after the unusual status is eliminated, the timing controller is controlled to first synchronize the signals to be outputted to the data driver and the scan driver and then output the synchronized signals to the data driver and the scan driver.