CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Republic of Korea Patent Application No. 10-2020-0155275, filed on Nov. 19, 2020, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of Technology

The present embodiment relates to a technology for driving pixels arranged on a display panel.

2. Description of the Prior Art

A display device may include a display panel and a pixel driving device. The display panel may have a plurality of pixels arranged thereon, and the brightness of each pixel may be controlled according to a driving current supplied from the pixel driving device. For example, a high driving current must be supplied to the pixel in order to control the pixel with high brightness, and a low driving current must be supplied to the pixel in order to control the pixel with low brightness. In general, the magnitude of the driving current for each pixel is determined according to a grayscale value of each pixel received by the pixel driving device.

The pixel driving device receives pixel data including a grayscale value for each pixel. In addition, the pixel driving device converts the grayscale value of the pixel data into an analog voltage, and supplies the analog voltage to each pixel. A driving transistor may be disposed in each pixel, and the magnitude of the driving current supplied to each pixel is determined according to the magnitude of the analog voltage supplied to the gate of the driving transistor. According to this process, when the pixel driving device receives pixel data including a low grayscale value, the brightness of the pixel may be controlled to be low, and when the pixel driving device receives pixel data including a high grayscale value, the brightness of the pixel may be controlled to be high.

The pixel driving device receives image data including pixel data from an external device. However, when the image data is affected by noise, the pixel data may have an abnormal grayscale value. Alternatively, when noise occurs in the internal circuit of the pixel driving device, the pixel data may have an abnormal grayscale value. If the pixel data has an abnormal grayscale value, the pixel may also emit light with abnormal brightness.

Light emission at abnormal brightness may cause a problem, especially, in high brightness light emission. In the case where light is emitted at high brightness, a high driving current is supplied to the pixels. However, if the above high driving current continues to be supplied for a predetermined time or more, heat is generated in lines to which the driving current is supplied, and some lines or devices around the same may be burned.

SUMMARY OF THE INVENTION

Against this background, the present embodiment provides a technology for preventing an excessive driving current from flowing due to noise. In another aspect, the present embodiment provides a technology for preventing the occurrence of an afterimage in a display panel due to abnormal light emission from each pixel. In another aspect, the present embodiment provides a technology for reducing the visibility of image noise caused by abnormal brightness.

In view of the foregoing, in one aspect, the present embodiment provides a pixel driving circuit that includes: a control circuit configured to change pixel data to a low-brightness grayscale value if a grayscale value of the pixel data is greater than a high-brightness reference value; a digital-to-analog converting circuit configured to convert the pixel data into an analog voltage; and an output circuit configured to output the analog voltage to the pixel to control the brightness of the pixel.

Another aspect, the present embodiment provides a pixel driving circuit including: a control circuit configured to compare grayscale values of pixels with a high-brightness reference value, and, if the grayscale values of N pixels (N is a natural number) exceed the high-brightness reference value, to switch its mode to a low-brightness mode; and an output circuit configured to output, to each pixel, a low-brightness analog voltage that causes each pixel to emit light at low brightness when the control circuit switches its mode to the low-brightness mode.

In another aspect, the present embodiment provides a pixel driving circuit including: a clock recovery circuit configured to recover a clock from an embedded clock signal, extract image data, and, if an abnormality is detected in the clock or the image data, generate a lock signal; a digital-to-analog converting circuit configured to convert pixel data included in the image data into analog voltages; an output circuit configured to output the analog voltages to pixels, thereby controlling brightness of the pixel; and a control circuit configured to change the pixel data or control the output circuit such that the output circuit outputs a low-brightness analog voltage that causes each pixel to emit light at low brightness if the lock signal is generated.

As described above, according to the present embodiment, it is possible to prevent an excessive driving current from flowing due to noise and to prevent burning in lines or devices due to the excessive driving current. In addition, according to the present embodiment, it is possible to prevent the occurrence of an afterimage in the display panel due to abnormal light emission from each pixel. Further, according to the present embodiment, it is possible to lower the visibility of image noise due to abnormal brightness.

