POWER VOLTAGE GENERATING CIRCUIT AND DISPLAY APPARATUS HAVING THE SAME AND METHOD OF PROTECTING DATA DRIVER USING THE SAME

• US 20190318705A1
• Filed: 04/05/2019
• Published: 10/17/2019
• Est. Priority Date: 04/11/2018
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: LEE, Dae-Sik, NAM, Yanguk, HAN, Songyi
• Granted Patent: US 10,957,277 B2
• Time in Patent Office: Days
• 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 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2310/0289 Details of voltage level shifters arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2330/00 Aspects of power supply; Aspects of display protection and defect management
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• 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 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: G09G 5/003 Details of a display terminal, the details relating to the control arrangement of the display terminal and to the interfaces thereto specific for a CRT G09G1/165; for a flat panel G09G3/2092
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power voltage generating circuit includes an input capacitor including a first end connected to an input node, and a second end connected to a ground, an inductor, an input switching element connected between the input node and a first end of the inductor, a control switching element including a control electrode connected to a switching controller configured to apply a switching control signal, an input electrode connected to a resistor, and an output electrode connected to a second end of the inductor, a diode including a first electrode connected to the second end of the inductor, and a second electrode connected to an output node, and an output capacitor connected between the output node and the ground, wherein the input switching element is configured to be turned off when a short circuit of a load connected to the output node is detected in a monitoring period.

Claims

1. A power voltage generating circuit comprising:

an input capacitor comprising a first end connected to an input node, and a second end connected to a ground;

an inductor;

an input switching element connected between the input node and a first end of the inductor;

a control switching element comprising a control electrode connected to a switching controller configured to apply a switching control signal, an input electrode connected to a resistor, and an output electrode connected to a second end of the inductor;

a diode comprising a first electrode connected to the second end of the inductor, and a second electrode connected to an output node; and

an output capacitor connected between the output node and the ground,

wherein the input switching element is configured to be turned off when a short circuit of a load connected to the output node is detected in a monitoring period.

2. The power voltage generating circuit of claim 1, wherein the input switching element is configured to be turned off when the control switching element is turned off and voltage drop of an output voltage, which is measured in the monitoring period, is equal to or greater than a reference voltage drop.

3. The power voltage generating circuit of claim 1, wherein the switching controller is configured to receive an output voltage of the output node as a feedback output voltage, and is configured to adjust a frequency of the switching control signal to adjust a level of the output voltage according to the feedback output voltage.

4. The power voltage generating circuit of claim 3, wherein the switching controller is configured to count a number of events in which a current sensing voltage of the input electrode of the control switching element is equal to or greater than a threshold voltage during the monitoring period, and

wherein the input switching element is configured to be turned off when the number of events is equal to or greater than a reference count.

5. A display apparatus comprising:

a display panel configured to display an image;

a gate driver configured to output a gate signal to the display panel;

a data driver configured to output a data voltage to the display panel; and

a power voltage generator configured to provide a gate driver power voltage to the gate driver, configured to provide a data driver power voltage to the data driver, and comprising a data driver power voltage generator that is configured to generate the data driver power voltage, the data driver power voltage generator comprising;

an input capacitor comprising a first end connected to an input node and a second end connected to a ground;

an inductor;

an input switching element connected between the input node and a first end of the inductor;

a control switching element comprising a control electrode connected to a switching controller that is configured to apply a switching control signal, an input electrode connected to a resistor, and an output electrode connected to a second end of the inductor;

a diode comprising a first electrode connected to the second end of the inductor, and a second electrode connected to an output node; and

an output capacitor connected between the output node and the ground,

wherein the data driver power voltage generator is configured to turn off the input switching element when a short circuit of a load connected to the output node is detected in a monitoring period.

6. The display apparatus of claim 5, wherein the control switching element is configured to be turned off, and voltage drop of the data driver power voltage outputted from the output node is configured to be measured, in the monitoring period, and

wherein the input switching element is configured to be turned off when the voltage drop of the data driver power voltage is equal to or greater than a reference voltage drop.

7. The display apparatus of claim 6, wherein the monitoring period is between a time when the data driver power voltage meets a normal output voltage and a scan start point of the gate driver in an initial driving period of the display apparatus.

8. The display apparatus of claim 6, wherein the display panel is configured to display the image in units of frames,

wherein each of the frames comprises an active period and a vertical blank period, and

wherein the monitoring period is in the vertical blank period.

9. The display apparatus of claim 8, wherein a hold period occurs before the monitoring period,

wherein the control switching element is configured to repetitively turn on and off during the hold period, and

wherein the hold period is in the vertical blank period.

10. The display apparatus of claim 6, wherein the data driver is configured to output a black data voltage corresponding to a black image to the display panel during the monitoring period.

11. The display apparatus of claim 5, wherein the switching controller is configured to receive a feedback data driver power voltage of the output node, and is configured to adjust a frequency of the switching control signal to adjust a level of the data driver power voltage according to the feedback data driver power voltage.

12. The display apparatus of claim 11, wherein the switching controller is configured to count a number of events in which a current sensing voltage of the input electrode of the control switching element is equal to or greater than a threshold voltage during the monitoring period, and

wherein the input switching element is configured to be turned off when the number of events is equal to or greater than a reference count.

13. The display apparatus of claim 12, wherein the monitoring period is between a time when the data driver power voltage meets a normal output voltage and a scan start point of the gate driver in an initial driving period of the display apparatus.

14. The display apparatus of claim 12, wherein the display panel is configured to display the image in units of frames,

wherein each of the frames comprises an active period and a vertical blank period, and

wherein the monitoring period is set in the vertical blank period.

15. The display apparatus of claim 14, wherein a hold period occurs before the monitoring period,

wherein the switching controller does not count the number of events during the hold period, and

wherein the hold period is in the vertical blank period.

16. The display apparatus of claim 14, wherein respective monitoring periods are respectively set in a plurality of frames,

wherein the switching controller is configured to count the number of events during the monitoring period in a single frame of the frames,

wherein each of the frames is determined as an abnormal frame when the number of events is equal to or greater than the reference count, and

wherein the input switching element is configured to be turned off when a number of abnormal frames is equal to or greater than a reference number of frames.

17. A method of protecting a data driver, the method comprising:

generating a gate driver power voltage;

outputting the gate driver power voltage to a gate driver;

generating a data driver power voltage;

outputting the data driver power voltage to the data driver;

outputting a gate signal to a display panel based on the gate driver power voltage;

outputting a data voltage to the display panel based on the data driver power voltage;

turning off a control switching element and measuring a voltage drop of the data driver power voltage outputted from an output node in a monitoring period; and

turning off an input switching element when the voltage drop of the data driver power voltage is equal to or greater than a reference voltage drop.

18. The method of claim 17, wherein the monitoring period is between a time when the data driver power voltage meets a normal output voltage and a scan start point of the gate driver in an initial driving period of a display apparatus.

19. The method of claim 17, wherein the display panel is configured to display an image in units of frames, each of the frames comprising an active period and a vertical blank period, and

wherein the monitoring period is set in the vertical blank period.

20. The method of claim 17, wherein the data driver is configured to output a black data voltage corresponding to a black image to the display panel during the monitoring period.