Display system and display driving apparatus thereof

A display driving apparatus includes an internal reference voltage generation circuit configured to generate and provide an internal reference voltage; a sensing circuit configured to simultaneously sense pixel signals provided from pixels of a display panel and the internal reference voltage, and output a reference voltage sensing signal generated by sensing of the internal reference voltage and pixel sensing signals generated by sensing of the pixel signals; and an output circuit configured to sequentially select the reference voltage sensing signal and the pixel sensing signals, convert the pixel sensing signals into pixel data, convert the reference voltage sensing signal into reference data, and transmits the pixel data and the reference data.

BACKGROUND

1. Technical Field

Various embodiments generally relate to a display system, and more particularly, to a display system and a display driving apparatus which sense pixel signals of pixels of a display panel and transmit pixel data corresponding to the pixel signals.

2. Related Art

A display system includes a display panel, a driver and a timing controller.

The driver converts digital display data, provided from the timing controller, into an analog source driving signal, and provides the analog source driving signal to the display panel. The driver is configured by one chip.

The display system may include a plurality of drivers in consideration of the size and resolution of the display panel.

The display panel may have a characteristic deviation between pixels. The characteristic deviation should be corrected. To this end, the driver is configured to generate pixel data corresponding to pixel signals generated by sensing pixel characteristics of pixels and provide the pixel data to the timing controller.

The pixel data provided from the driver to the timing controller may include not only the pixel characteristics but also driver characteristics including electrical characteristics of the driver itself. Therefore, the unnecessary driver characteristics need to be excluded from the pixel data provided to the timing controller.

The gains and offsets of internal circuits of the driver may vary by variations in power supply voltage, temperature, etc., and due to this fact, the driver characteristics may vary. Variations in driver characteristics also need to be excluded from the pixel data.

To this end, the driver may be configured to receive a reference voltage from the outside, generate reference data by sensing the reference voltage and transmit the reference data to the timing controller, and the timing controller may be configured to correct the driver characteristics, that is, errors, included in the pixel data provided from the driver, by the reference data.

However, this method requires that a component for providing the reference voltage to the driver from the outside be added. Therefore, there is a problem in that the manufacturing cost increases.

Also, the above method has a problem in that external noise is introduced into the driver through a path which provides the reference voltage to the inside of the driver from the outside.

SUMMARY

Various embodiments are directed to a display system and a display driving apparatus thereof in which a driver generates an internal reference voltage and reference data for correcting pixel data is generated using the internal reference voltage, thereby capable of reducing the manufacturing cost.

Also, various embodiments are directed to a display system and a display driving apparatus thereof in which reference data for correcting pixel data is generated using a reference voltage generated inside a driver, thereby capable of decreasing introduction of external noise into the driver.

Further, various embodiments are directed to a display system and a display driving apparatus thereof in which an internal reference voltage or an external reference voltage may be selected according to necessity to generate reference data for correcting pixel data, thereby capable of being actively adapted for a system environment.

In addition, various embodiments are directed to a display system and a display driving apparatus thereof in which, in order to generate reference data for correcting pixel data, a master driver uses an internal reference voltage and a slave driver shares the internal reference voltage of the master driver, thereby capable of reducing the manufacturing cost and decreasing introduction of external noise.

In an embodiment, a display driving apparatus may include: an internal reference voltage generation circuit configured to generate and provide an internal reference voltage; a sensing circuit configured to simultaneously sense pixel signals provided from pixels of a display panel and the internal reference voltage, and output a reference voltage sensing signal generated by sensing of the internal reference voltage and pixel sensing signals generated by sensing of the pixel signals; and an output circuit configured to sequentially select the reference voltage sensing signal and the pixel sensing signals, convert the pixel sensing signals into pixel data, convert the reference voltage sensing signal into reference data, and transmit the pixel data and the reference data.

In an embodiment, a display driving apparatus may include: an internal reference voltage generation circuit configured to generate and provide an internal reference voltage; a selection circuit configured to provide a reference voltage by selecting one of an external reference voltage provided from the outside reference voltage and the internal reference voltage; a sensing circuit configured to simultaneously sense pixel signals provided from pixels of a display panel and the reference voltage, and output a reference voltage sensing signal generated by sensing of the reference voltage and pixel sensing signals generated by sensing of the pixel signals; and an output circuit configured to sequentially select the reference voltage sensing signal and the pixel sensing signals, convert the pixel sensing signals into pixel data, convert the reference voltage sensing signal into reference data, and transmit the pixel data and the reference data.

In an embodiment, a display system may include: a master driver configured to generate an internal reference voltage and output the internal reference voltage; and a slave driver configured to receive the internal reference voltage of the master driver, wherein the master driver generates the internal reference voltage, simultaneously senses first pixel signals provided from first pixels of a display panel and the internal reference voltage, converts a first reference voltage sensing signal generated by sensing of the internal reference voltage into first reference data, converts first pixel sensing signals generated by sensing of first pixel signals into first pixel data, and transmits the first reference data and the first pixel data, and wherein the slave driver receives the internal reference voltage, simultaneously senses second pixel signals provided from second pixels of the display panel and the internal reference voltage, converts a second reference voltage sensing signal generated by sensing of the internal reference voltage into second reference data, converts second pixel sensing signals generated by sensing of second pixel signals into second pixel data, and transmits the second reference data and the second pixel data.

According to the embodiments of the present disclosure, an internal reference voltage may be generated inside a driver, and reference data generated by sensing characteristics of the driver using the internal reference voltage may be generated and transmitted.

Therefore, according to the embodiments of the present disclosure, a component for providing an external reference voltage is not needed, and it is not necessary to form a channel for providing the external reference voltage to the inside of the driver. As a result, according to the embodiments of the present disclosure, the manufacturing cost may be reduced, and introduction of external noise may be decreased.

Also, according to the embodiments of the present disclosure, in order to generate reference data for correcting pixel data, an internal reference voltage or an external reference voltage may be selected according to necessity. Therefore, according to the embodiments of the present disclosure, it is possible to be actively adapted to a system environment.

Further, according to the embodiments of the present disclosure, in order to generate reference data for correcting pixel data, an internal reference voltage generated by a master driver among a plurality of drivers may be shared with a slave driver among the plurality of drivers. Therefore, according to the embodiments of the present disclosure, a mismatch in internal reference voltage between drivers may be eliminated, the manufacturing cost may be reduced, and introduction of external noise may be decreased.

DETAILED DESCRIPTION

The present disclosure discloses a display driving apparatus which, in order to eliminate characteristic deviations among pixels of a display panel, outputs pixel data by sensing pixel signals and outputs reference data by sensing an internal reference voltage. Also, the present disclosure discloses a display system including the display driving apparatus described above.

In the present disclosure, the display driving apparatus may be understood as corresponding to a driver to be described later which provides a source driving signal to the display panel in correspondence to display data of a timing controller, and may be configured by one chip.

The above-described display driving apparatus of the present disclosure may have driver characteristics including its own electrical characteristics. The driver characteristics of the display driving apparatus may vary as the gains and offsets of internal circuits vary by variations in power supply voltage, temperature, etc.

The reference data may be used to exclude the driver characteristics from the pixel data, and the pixel data may be used to compensate display data so as to eliminate characteristic deviations among the pixels.

As illustrated inFIG.1, a display system in accordance with an embodiment of the present disclosure includes a display panel100, a timing controller10and a plurality of drivers20,22and24.

The display panel100may be exemplified as using an organic light emitting diode (OLED) panel.

The display panel100includes a pixel array (not illustrated) in which pixels (not illustrated) are arranged in the form of a matrix. For example, the pixel array may include R (red) pixels, G (green) pixels and B (blue) pixels for implementation of colors, and may further include W (white) pixels for luminance.

Each pixel may include a light emitting element (not illustrated) and a pixel circuit (not illustrated). The pixel circuit is configured to supply a current, corresponding to a source driving signal D of the drivers20,22and24, to the light emitting device. To this end, the pixel circuit may include a driving transistor which provides the current, corresponding to the source driving signal D, to the light emitting element.

Each pixel may have pixel characteristics such as an electrical characteristic deviation of the driving transistor and a degradation deviation of the light emitting element with the lapse of time. As a result, the respective pixels may non-uniformly emit light due to pixel characteristics.

The pixel circuit of each pixel may further include a circuit for sensing pixel characteristics, and may be configured to provide a pixel signal P corresponding to the pixel characteristics.

The pixel signal P may be provided to one of the drivers20,22and24corresponding to the pixel. Each of the drivers20,22and24is configured to provide sensing data PS, including pixel data corresponding to the pixel signal P, to the timing controller10.

Pixel characteristics of the pixels may be compensated for by the timing controller10.

The timing controller10is configured to receive display data from an external source, provide display data DS configured as packets to the plurality of drivers20,22and24and receive the sensing data PS from each of the drivers20,22and24.

According to the embodiment of the present disclosure, the sensing data PS includes pixel data and reference data. The pixel data corresponds to the pixel signal P generated by sensing each pixel to compensate for pixel characteristics, and the reference data is to correct errors of the pixel data caused by the driver characteristics of each of the drivers20,22and24. Detailed description of the pixel data and the reference data will be made later with reference toFIG.2.

The timing controller10may receive the sensing data PS of each of the drivers20,22and24, may correct driver characteristics, that is, errors, included in the pixel data, by the reference data, and may compensate display data of each of the drivers20,22and24by the error-corrected pixel data, thereby compensating for pixel characteristics.

That is to say, the timing controller10may compensate the display data, received from the external source, by using the sensing data PS, and may provide compensated display data DS.

Each of the plurality of drivers20,22and24is configured by one chip.

In order for display, each of the drivers20,22and24is configured to receive the digital display data DS provided from the timing controller10, generate the analog source driving signal D corresponding to the display data DS, and provide the source driving signal D to each of the pixels of the display panel100.

In order to compensate for pixel characteristics of the pixels, each of the drivers20,22and24is configured to receive the pixel signal P generated by sensing the pixel characteristics of each of the pixels of the display panel100, and generate the pixel data corresponding to the pixel signal P.

Further, each of the drivers20,22and24is configured to generate the reference data for driver characteristics, by using an internal reference voltage.

Each of the drivers20,22and24is configured to provide the sensing data PS, including the pixel data and the reference data generated as described above, to the timing controller10.

Each of the drivers20,22and24will be described below with reference toFIG.2.FIG.2representatively illustrates the driver20, and it may be understood that the drivers22and24have the same structure as the driver20ofFIG.2.

The driver20ofFIG.2is illustrated as including components which receive the pixel signal P, generate the pixel data and the reference data and transmit the sensing data PS including the pixel data and the reference data. For the sake of convenience in explanation, in the driver20, the illustration of components which convert the display data DS into the source driving signal D will be omitted.

Referring toFIG.2, the driver20includes a sensing circuit30, an internal reference voltage generation circuit34and an output circuit36.

The internal reference voltage generation circuit34may generate and provide an internal reference voltage Vri, and may be configured using a general circuit which generates a bandgap reference voltage. For example, the internal reference voltage generation circuit34may generate and output the internal reference voltage Vri of a preset level by using the bandgap reference voltage.

The sensing circuit30is configured to receive the pixel signal P from each of the pixels of the display panel100, receive the internal reference voltage Vri from the internal reference voltage generation circuit34and output a reference voltage sensing signal and a pixel sensing signal.

The pixel signal P may be understood as including a plurality of pixel signals, that is, pixel signals P<1>, P<2>, . . . , <Pn>, received from a plurality of pixels corresponding to the driver20.

The sensing circuit30simultaneously senses the plurality of pixel signals P<1>, P<2>, . . . , <Pn>, provided from the plurality of pixels of the display panel100, and the internal reference voltage Vri. By the sensing, the sensing circuit30simultaneously generates pixel sensing signals corresponding to the plurality of pixel signals P<1>, P<2>, . . . , <Pn> and a reference voltage sensing signal corresponding to the internal reference voltage Vri. The sensing circuit30is configured to provide the reference voltage sensing signal and the pixel sensing signals which are simultaneously generated, to a selection circuit37of the output circuit36.

To this end, the sensing circuit30may include a pixel sensing circuit31and a reference voltage sensing circuit32.

The pixel sensing circuit31may sample and hold pixel signals for sensing the pixel signals, and may include switches SWp for sampling and capacitors Cp for holding.

The pixel signals are sampled during a time when the switches SWp are turned on, and the sampled pixel signals are stored and held in the capacitors Cp. Pixel sensing signals which are generated as voltages are held in the capacitors Cp may be provided to the selection circuit37.

The pixel sensing circuit31is configured to simultaneously select the plurality of pixel signals P<1>, P<2>, . . . , <Pn>, simultaneously perform the sampling and holding of the plurality of pixel signals P<1>, P<2>, . . . , <Pn> and simultaneously output the pixel sensing signals which are generated by the sampling and holding of the plurality of pixel signals P<1>, P<2>, . . . , <Pn>.

The reference voltage sensing circuit32may sample and hold the internal reference voltage Vri for sensing the internal reference voltage Vri, and may include a switch SWr for sampling and a capacitor Cr for holding.

The internal reference voltage Vri is sampled during a time when the switch SWr is turned on, and the sampled internal reference voltage Vri is stored and held in the capacitor Cr. A reference voltage sensing signal which is generated as a voltage is held in the capacitor Cr may be provided to the selection circuit37.

The pixel sensing circuit31and the reference voltage sensing circuit32simultaneously sample the plurality of pixel signals P<1>, P<2>, . . . , <Pn> and the internal reference voltage Vri. In other words, the pixel sensing signals and the reference voltage sensing signal may be generated by being simultaneously sampled and held. Although a control signal for controlling a sampling time point is not illustrated inFIG.2, the control signal may be provided from the timing controller10. In this case, the control signal may be provided to the switches SWp of the pixel sensing circuit31for sampling the plurality of pixel signals P<1>, P<2>, . . . , <Pn> and the switch SWr of the reference voltage sensing circuit32for sampling the internal reference voltage Vri, in such a way to have the same phase.

By the above description, the pixel sensing circuit31and the reference voltage sensing circuit32are configured to simultaneously sample and hold the plurality of pixel signals P<1>, P<2>, . . . , <Pn> and the internal reference voltage Vri and simultaneously output the pixel sensing signals and the reference voltage sensing signal generated by the sampling and holding.

The output circuit36is configured to sequentially select the reference voltage sensing signal and the pixel sensing signals of the sensing circuit30which are simultaneously received, convert the pixel sensing signals into pixel data, convert the reference voltage sensing signal into reference data, and transmit sensing data PS including the pixel data and the reference data.

To this end, the output circuit36may include the selection circuit37and an analog-to-digital converter (ADC)38.

The selection circuit37may be configured by a multiplexer, and sequentially selects the reference voltage sensing signal and the pixel sensing signals of the sensing circuit30which are simultaneously received, and provides the sequentially selected reference voltage sensing signal and pixel sensing signals to the analog-to-digital converter (ADC)38. The selection circuit37may perform the selection operation by a control signal for sequentially selecting the reference voltage sensing signal and the pixel sensing signals, and illustration and detailed description of the control signal are be omitted.

The analog-to-digital converter38converts the reference voltage sensing signal provided from the selection circuit37into the reference data, and converts the pixel sensing signals provided from the selection circuit37into the pixel data. The analog-to-digital converter38transmits the sensing data PS including the sequentially converted reference data and pixel data.

In the embodiment of the present disclosure implemented as illustrated inFIGS.1and2, an internal reference voltage may be generated in each of the drivers22,24and26, and reference data generated by sensing characteristics of the driver using the internal reference voltage may be generated and transmitted.

Therefore, according to the embodiment of the present disclosure, a component for providing an external reference voltage is not needed, and it is not necessary to form a channel for providing the external reference voltage to the inside of the driver. Accordingly, the manufacturing cost may be reduced, and the introduction of external noise may be decreased.

Meanwhile, as illustrated inFIGS.3to5, embodiments of the present disclosure may be configured to, in order to generate reference data for correcting pixel data, select an internal reference voltage or an external reference voltage according to necessity.

An embodiment ofFIG.3is configured such that an external reference voltage Vre is provided to the drivers20,22and24. The configuration of the embodiment ofFIG.3is the same as that ofFIG.1except that the external reference voltage Vre is provided to the drivers20,22and24, and thus, repeated description thereof will be omitted.

The driver20ofFIG.3may be configured to select the internal reference voltage Vri as illustrated inFIG.4or select the external reference voltage Vre as illustrated inFIG.5. The drivers20,22and24ofFIG.3have the same structure. Therefore, the configuration of the driver20will be representatively described below with reference toFIGS.4and5, and the structures of the drivers22and24may be understood by referring toFIGS.4and5.

Referring toFIG.4, the driver20includes a selection circuit40, and the selection circuit40is configured to select one of the external reference voltage Vre provided from the outside reference voltage and the internal reference voltage Vri and provide the selected one as a reference voltage to the reference voltage sensing circuit32of the sensing circuit30.

The driver20ofFIGS.4and5has the same structure as the driver20ofFIG.2except that the driver20ofFIGS.4and5receives the external reference voltage Vre and includes the selection circuit40. Thus, description for the detailed configuration and operation of the driver20ofFIGS.4and5will be omitted.

The selection circuit40may be understood as including a multiplexer.

The selection circuit40may receive a selection control signal Cs which is provided from the timing controller10, and may select the internal reference voltage Vri or the external reference voltage Vre depending on the state of the selection control signal Cs.

Namely, for example, when the selection control signal Cs is provided as a logic high, the selection circuit40may select the internal reference voltage Vri and provide the internal reference voltage Vri as a reference voltage to the reference voltage sensing circuit32of the sensing circuit30, as illustrated inFIG.4. When the selection control signal Cs is provided as a logic low, the selection circuit40may select the external reference voltage Vre and provide the external reference voltage Vre as a reference voltage to the reference voltage sensing circuit32of the sensing circuit30, as illustrated inFIG.5.

The reference voltage sensing circuit32receives one of the external reference voltage Vre and the internal reference voltage Vri as a reference voltage, samples and holds the reference voltage, and outputs a reference voltage sensing signal generated by the sampling and holding.

The sampling and holding of the pixel signal sensing circuit31and the sampling and holding of the reference voltage of the reference voltage sensing circuit32are the same as those in the operation of the driver20ofFIG.2, and thus, repeated description will be omitted.

The operation of the output circuit36is also the same as that in the operation of the driver20ofFIG.2, and thus, repeated description will be omitted.

The embodiment ofFIGS.3to5may, in order to generate reference data for correcting pixel data, select the internal reference voltage Vri or the external reference voltage Vre according to necessity. Therefore, the embodiment of the present disclosure may be actively adapted to a system environment.

Meanwhile, as illustrated inFIGS.6to8, an embodiment of the present disclosure may be configured to share an internal reference voltage generated by a master driver among a plurality of drivers with a slave driver among the plurality of drivers.

InFIG.6, the driver20is set as a master driver, and the drivers22and24are set as slave drivers. Hereinafter, the driver20is referred to as a master driver, and the drivers22and24are referred to as slave drivers.

The embodiment ofFIG.6is configured such that the master driver20provides the internal reference voltage Vri to the slave drivers22and24. The embodiment ofFIG.6is the same as that ofFIG.1except that the master driver20provides the internal reference voltage Vri to the slave drivers22and24, and thus, repeated description thereof will be omitted.

The master driver20may be configured as illustrated inFIG.7, and each of the slave drivers22and24may be configured as illustrated inFIG.8.

The master driver20ofFIG.7is different from the driver20ofFIG.2in that the master driver20ofFIG.7provides the internal reference voltage Vri of the internal reference voltage generation circuit34to the slave drivers22and24. Except for this, the master driver20ofFIG.7has the same structure as the driver20ofFIG.2. Therefore, repeated description for the detailed configuration of the master driver20ofFIG.7will be omitted.

The slave driver22ofFIG.8is different from the driver20ofFIG.2in that the slave driver22ofFIG.8does not have the internal reference voltage generation circuit34and the internal reference voltage Vri of the master driver20is provided to the reference voltage sensing circuit32. Except for this, the slave driver22ofFIG.8has the same structure as the driver20ofFIG.2. Therefore, repeated description for the detailed configuration of the slave driver22ofFIG.8will be omitted.

According to the embodiment ofFIGS.6to8, the master driver20generates reference data by sensing driver characteristics using the internal reference voltage Vri. Each of the slave drivers22and24generates reference data by sensing driver characteristics by using the internal reference voltage Vri of the master driver20.

The configuration ofFIGS.6to8shares the internal reference voltage Vri of the master driver20, and thus, it is possible to solve the problem caused due to the mismatch of the internal reference voltage Vri among the drivers20,22and24.

In the configuration ofFIGS.6to8, each of the slave drivers22and24does not include the internal reference voltage generation circuit34, and thus, in correspondence thereto, may have an advantage in terms of chip size.

Therefore, according to the embodiment of the present disclosure implemented as illustrated inFIGS.6to8, the manufacturing cost may be reduced, and introduction of external noise may be decreased.