阅读说明：本技术 有机发光二极管显示装置和操作其的方法 (Organic light emitting diode display device and method of operating the same ) 是由 金均浩 权祥颜 慎容震 白俊锡 于 2021-04-01 设计创作，主要内容包括：提供了有机发光二极管(OLED)显示装置和操作其的方法。所述OLED显示装置包括具有多个像素行的显示面板和驱动显示面板的面板驱动器。面板驱动器包括：确定电路,从多个像素行中选择一个像素行,基于一个像素行的输入图像数据确定负载数据,并且确定与负载数据对应的目标迁移率数据；感测电路,通过对一个像素行执行迁移率感测操作来产生与包括在一个像素行中的多个像素的驱动晶体管的迁移率值对应的迁移率感测数据；以及电流控制电路,将迁移率感测数据和目标迁移率数据进行比较以产生结果,并且根据结果调整流过显示面板的面板电流。(An Organic Light Emitting Diode (OLED) display device and a method of operating the same are provided. The OLED display device includes a display panel having a plurality of pixel rows and a panel driver driving the display panel. The panel driver includes: a determination circuit that selects one pixel row from the plurality of pixel rows, determines load data based on input image data of the one pixel row, and determines target mobility data corresponding to the load data; a sensing circuit generating mobility sensing data corresponding to mobility values of driving transistors of a plurality of pixels included in one pixel row by performing a mobility sensing operation on the one pixel row; and a current control circuit comparing the mobility sensing data and the target mobility data to generate a result, and adjusting a panel current flowing through the display panel according to the result.)

1. An organic light emitting diode display device, comprising:

a display panel including a plurality of pixel rows and a panel driver configured to drive the display panel, the panel driver comprising:

a determination circuit configured to select one pixel row from the plurality of pixel rows, determine load data based on input image data of the selected one pixel row, and determine target mobility data corresponding to the load data;

a sensing circuit configured to generate mobility sensing data corresponding to mobility values of driving transistors of a plurality of pixels included in the selected one pixel row by performing a mobility sensing operation on the selected one pixel row; and

a current control circuit configured to compare the mobility sensing data and the target mobility data to generate a result, and adjust a panel current flowing through the display panel according to the result.

2. The organic light emitting diode display device according to claim 1, wherein the determination circuit calculates a plurality of pixel row load data of the plurality of pixel rows based on the input image data of the plurality of pixel rows, and selects the one pixel row having the largest pixel row load data among the plurality of pixel row load data of the plurality of pixel rows.

3. The organic light emitting diode display device of claim 1, wherein the selected one pixel row is an uppermost pixel row or a lowermost pixel row among the plurality of pixel rows.

4. The organic light emitting diode display device according to claim 1, wherein the determination circuit sequentially selects the plurality of pixel rows such that selection of the one pixel row is changed every frame period.

5. The organic light emitting diode display device of claim 1, wherein the determination circuit calculates the load data by dividing the input image data of the selected one pixel row by maximum image data of the one pixel row.

6. The organic light emitting diode display device of claim 1, wherein the determination circuit determines the target mobility data as maximum target mobility data corresponding to reference load data when the load data is greater than or equal to the reference load data.

7. The organic light emitting diode display device of claim 1, wherein the current control circuit decreases the panel current when the mobility sensing data is greater than the target mobility data and increases the panel current when the mobility sensing data is less than the target mobility data.

8. The organic light emitting diode display device according to any one of claims 1 to 7, wherein the panel driver further comprises:

an overcurrent protection circuit configured to stop an operation of the organic light emitting diode display device when the mobility sensing data is greater than the target mobility data by more than a turn-off reference amount during a plurality of frame periods corresponding to a turn-off reference time.

9. A method of operating an organic light emitting diode display device comprising a display panel having a plurality of rows of pixels, the method comprising:

selecting a pixel row from the plurality of pixel rows;

determining load data based on the input image data of the selected one pixel row;

determining target mobility data corresponding to the load data;

generating mobility sensing data by performing a mobility sensing operation on the selected one pixel row, the mobility sensing data corresponding to mobility values of driving transistors of a plurality of pixels included in the one pixel row;

comparing the mobility sensing data and the target mobility data to produce a result; and

adjusting a panel current flowing through the display panel according to the result.

10. An organic light emitting diode display device, comprising:

a display panel including a plurality of pixel rows, a plurality of data lines, and a plurality of sensing lines, wherein each pixel row includes a plurality of pixels, and each pixel is connected to a corresponding data line of the plurality of data lines and a corresponding sensing line of the plurality of sensing lines; and

a panel driver configured to drive the display panel,

wherein the panel driver is configured to: outputting data voltages to the plurality of data lines during an active period of a frame period, and sensing voltages from the plurality of sensing lines during a sensing period of the frame period,

wherein the panel driver is configured to: determining a sense voltage variation from the sense voltage received from one of the plurality of pixel rows, determining mobility data from the sense voltage variation, comparing the mobility data to a target value to produce a result, and adjusting a panel current of the display panel based on the result.

Technical Field

Exemplary embodiments of the inventive concept relate to a display apparatus, and more particularly, to an Organic Light Emitting Diode (OLED) display apparatus and a method of operating the OLED display apparatus.

Background

A display device such as an Organic Light Emitting Diode (OLED) display device includes a display panel having a plurality of pixels for displaying an image. The current flowing in the pixel during the operation of the OLED display device may be referred to as a panel current. If the panel current is controlled not to exceed a predetermined maximum current, power consumption can be reduced. The controlling of the panel current includes sensing a value of the panel current. For example, the panel current may be sensed by using a series resistor connected in series with the display panel. However, since a series resistor having a very large resistance value is required to sense the panel current, the cost and power consumption of the OLED display device are greatly increased due to the series resistor.

Disclosure of Invention

At least one exemplary embodiment of the present disclosure provides an Organic Light Emitting Diode (OLED) display device capable of controlling a panel current without a series resistor for sensing the panel current.

At least one exemplary embodiment of the present disclosure provides a method of operating an OLED display device capable of controlling a panel current without a series resistor for sensing the panel current.

According to an exemplary embodiment of the disclosure, there is provided an OLED display device having a display panel including a plurality of pixel rows and a panel driver configured to drive the display panel. The panel driver includes: a determination circuit configured to select one pixel row from the plurality of pixel rows, determine load data based on input image data of the one pixel row, and determine target mobility data corresponding to the load data; a sensing circuit configured to generate mobility sensing data by performing a mobility sensing operation on the one pixel row, the mobility sensing data corresponding to mobility values of driving transistors of a plurality of pixels included in the one pixel row; and a current control circuit configured to compare the mobility sensing data and the target mobility data to generate a result, and adjust a panel current flowing through the display panel according to the result.

In an exemplary embodiment, the determination circuit calculates a plurality of pixel row load data of the plurality of pixel rows based on the input image data of the plurality of pixel rows, and selects the one pixel row having the largest pixel row load data among the plurality of pixel row load data of the plurality of pixel rows.

In an exemplary embodiment, the one pixel row selected is an uppermost pixel row or a lowermost pixel row among the plurality of pixel rows.

In an exemplary embodiment, the determination circuit sequentially selects the plurality of pixel rows such that the selection of the one pixel row is changed every frame period.

In an exemplary embodiment, the determination circuit calculates the load data by dividing the input image data of the one pixel row by the maximum image data of the one pixel row.

In an exemplary embodiment, the determination circuit determines the target mobility data as maximum target mobility data corresponding to the reference load data when the load data is greater than or equal to the reference load data.

In an exemplary embodiment, the determination circuit includes a memory device configured to store a plurality of target mobility values corresponding to a plurality of load values, respectively, and determines target mobility data corresponding to the load data by using the memory device.

In an exemplary embodiment, the determination circuit determines two load values adjacent to a load value represented by the load data among the plurality of load values, obtains two target mobility values corresponding to the two load values among the plurality of target mobility values from the memory device, and interpolates the target mobility data from the two target mobility values.

In an exemplary embodiment, the plurality of target mobility values stored in the memory device are measured by using a sensing circuit before performing an aging process of the display panel.

In an exemplary embodiment, in a sensing period of each frame period, a panel driver applies a reference voltage to a plurality of pixels included in the one pixel row, senses a sensing voltage variation of a plurality of sensing lines coupled to the plurality of pixels during a sensing time within the sensing period by using a sensing circuit, and generates mobility sensing data based on the sensing voltage variation.

In an exemplary embodiment, the current control circuit reduces the panel current when the mobility sensing data is greater than the target mobility data, and increases the panel current when the mobility sensing data is less than the target mobility data.

In an exemplary embodiment, the current control circuit generates the output image data supplied to the data driver included in the panel driver by reducing the input image data of the plurality of pixel rows such that the data voltage applied to the plurality of pixel rows is reduced when the mobility sensing data is greater than the target mobility data. When the mobility sensing data is less than the target mobility data, the current control circuit generates output image data supplied to the data driver by increasing input image data of the plurality of pixel rows such that data voltages applied to the plurality of pixel rows are increased.

In an exemplary embodiment, the panel driver further includes an overcurrent protection circuit configured to: stopping an operation of the OLED display device when mobility sensing data is greater than target mobility data by more than a turn-off reference amount during a plurality of frame periods corresponding to a turn-off reference time.

According to a disclosed exemplary embodiment, there is provided a method of operating an OLED display device including a display panel having a plurality of pixel rows. In the method: selecting a pixel row from the plurality of pixel rows; determining load data based on the input image data of the one pixel row; determining target mobility data corresponding to the load data; generating mobility sensing data by performing a mobility sensing operation on the one pixel row, the mobility sensing data corresponding to mobility values of driving transistors of a plurality of pixels included in the one pixel row; comparing the mobility sensing data and the target mobility data to generate a result; and adjusting a panel current flowing through the display panel according to the result.

In an exemplary embodiment, to select the one pixel row, a plurality of pixel row loading data of the plurality of pixel rows is calculated based on input image data of the plurality of pixel rows, and the one pixel row having a largest pixel row loading data among the plurality of pixel row loading data of the plurality of pixel rows is selected.

In an exemplary embodiment, in order to select the one pixel row, an uppermost pixel row or a lowermost pixel row among the plurality of pixel rows is selected.

In an exemplary embodiment, to select the one pixel row, the plurality of pixel rows are sequentially selected such that the selection of the one pixel row is changed every frame period.

In an exemplary embodiment, to adjust the panel current, the panel current is decreased when the mobility sensing data is greater than the target mobility data, and the panel current is increased when the mobility sensing data is less than the target mobility data.

In an exemplary embodiment, in order to reduce the panel current, the data voltage applied to the plurality of pixel rows is reduced. In order to increase the panel current, the data voltage applied to the plurality of pixel rows is increased.

In an exemplary embodiment, when the mobility sensing data is greater than the target mobility data by more than the turn-off reference amount during a plurality of frame periods corresponding to the turn-off reference time, the operation of the OLED display device is stopped.

According to the disclosed exemplary embodiments, an Organic Light Emitting Diode (OLED) display device including a display panel and a panel driver is provided. The display panel includes a plurality of pixel rows, a plurality of data lines, and a plurality of sensing lines. Each pixel row includes a plurality of pixels, each pixel connected to a corresponding data line of the plurality of data lines and a corresponding sense line of the plurality of sense lines. The panel driver is configured to drive the display panel. The panel driver is configured to output a data voltage to the plurality of data lines during an active period of a frame period, and sense a sensing voltage from the plurality of sensing lines during a sensing period of the frame period. The panel driver is configured to determine a sense voltage variation from a sense voltage received from one of the plurality of pixel rows, determine mobility data from the sense voltage variation, compare the mobility data to a target value to produce a result, and adjust a panel current of the display panel based on the result.

In an embodiment, the panel driver includes a current control circuit configured to stop an operation of the OLED display device when the mobility data exceeds the target value by more than a reference amount for more than N frame periods, where N is at least 1.

In an embodiment, the panel driver increases the panel current when the mobility data exceeds a target value and the temperature of the display panel is greater than a threshold value.

As described above, in an OLED display device and a method of operating the same according to at least one disclosed exemplary embodiment, one pixel row is selected from a plurality of pixel rows, load data is determined based on input image data for the selected one pixel row, target mobility data corresponding to the load data is determined, mobility sensing data is generated by performing a mobility sensing operation on the one pixel row, and a panel current is adjusted by comparing the mobility sensing data and the target mobility data. Accordingly, the OLED display device can control the panel current by using the mobility sensing data without a series resistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device can be reduced.

Further, in an OLED display device and a method of operating the OLED display device according to at least one exemplary embodiment of the disclosure, an overcurrent protection operation may be performed using mobility sensing data.

Drawings

The disclosed exemplary embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 1 is a block diagram illustrating an Organic Light Emitting Diode (OLED) display device according to an exemplary disclosed embodiment.

Fig. 2 is a diagram showing an example of target mobility data according to load data.

Fig. 3 is a diagram for describing an example of a target mobility storage block.

Fig. 4 is a diagram showing a data driver and a display panel for describing an example of a mobility sensing operation.

Fig. 5 is a timing diagram for describing an example of the mobility sensing operation.

Fig. 6 is a graph showing an example of the mobility of the driving transistor according to temperature.

Fig. 7 is a flowchart illustrating a method of operating an OLED display device according to an exemplary embodiment of the disclosure.

Fig. 8 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 7.

Fig. 9 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment.

Fig. 10 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 9.

Fig. 11 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment.

Fig. 12 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 11.

Fig. 13 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment.

Fig. 14 is a block diagram illustrating an electronic device including an OLED display device according to an exemplary disclosed embodiment.

Detailed Description

Hereinafter, exemplary embodiments of the inventive concept will be explained in detail with reference to the accompanying drawings.

Fig. 1 is a block diagram illustrating an Organic Light Emitting Diode (OLED) display device according to an exemplary disclosed embodiment, fig. 2 is a diagram illustrating an example of target mobility data according to load data, fig. 3 is a diagram for describing an example of a target mobility storage block (e.g., a memory device), fig. 4 is a diagram illustrating a data driver and a display panel for describing an example of a mobility sensing operation, fig. 5 is a timing diagram for describing an example of a mobility sensing operation, and fig. 6 is a diagram illustrating an example of mobility of a driving transistor according to temperature.

Referring to fig. 1, an OLED display device 100 according to the disclosed exemplary embodiment includes a display panel 110 including a plurality of pixel rows (e.g., PXR1, PXR2, … …, PXRN) and a panel driver 120 (e.g., driver circuit) driving the display panel 110. In an exemplary embodiment, the panel driver 120 includes a scan driver 130 (e.g., a driver circuit) that supplies the first scan signal SS1 and the second scan signal SS2 to the plurality of pixel rows, a data driver 140 (e.g., a driver circuit) that supplies the data voltage DV to the plurality of pixel rows, a sensing circuit 160 that senses driving characteristics of driving transistors of the plurality of pixel rows, and a controller 170 (e.g., a control circuit) that controls the operation of the OLED display device 100.

The display panel 110 includes a plurality of pixel rows PXR1, PXR2, … …, PXRN each including a plurality of pixels PX. In an exemplary embodiment, each pixel PX of a given pixel row receives the same first scan signal SS1 and the same second scan signal SS 2. In an embodiment, the display panel 110 further includes a plurality of first scan lines (or gate lines) for transmitting the first scan signal SS1, a plurality of second scan lines for transmitting the second scan signal SS2, a plurality of data lines DL, and a plurality of sensing lines SL. In an exemplary embodiment, each pixel PX includes an Organic Light Emitting Diode (OLED), and the display panel 110 is an OLED panel.

For example, as shown in fig. 4, each pixel PX includes a storage capacitor CST, a first switching transistor ST1, a second switching transistor ST2, a driving transistor DT, and an organic light emitting diode EL. The first switching transistor ST1 couples the data line DL to a first electrode of the storage capacitor CST in response to the first scan signal SS1, and the second switching transistor ST2 couples the sensing line SL to a second electrode of the storage capacitor CST in response to the second scan signal SS 2. The storage capacitor CST may store the data voltage DV transmitted through the data line DL. The driving transistor DT generates a driving current based on the data voltage DV stored in the storage capacitor CST. The organic light emitting diode EL emits light based on the driving current generated by the driving transistor DT. Fig. 4 illustrates a pixel PX of the OLED display device 100 according to an exemplary embodiment of the inventive concept. However, the pixel PX is not limited to the example shown in fig. 4. For example, the pixel PX may include a different number of transistors from those shown in fig. 4.

The scan driver 130 generates a first scan signal SS1 and a second scan signal SS2 based on the scan control signal SCTRL received from the controller 170. The scan driver 130 may sequentially supply the first scan signal SS1 to the plurality of pixels PX by pixel row, and may sequentially supply the second scan signal SS2 to the plurality of pixels PX by pixel row. In some exemplary embodiments, the scan control signal SCTRL includes a scan start signal and a scan clock signal, but is not limited thereto. In some exemplary embodiments, the scan driver 130 may be integrated or formed in a peripheral region of the display panel 110. In other exemplary embodiments, the scan driver 130 may be implemented with one or more integrated circuits.

The data driver 140 generates the data voltage DV based on the output image data ODAT and the data control signal DCTRL received from the controller 170, and supplies the data voltage DV to the plurality of pixels PX. In some exemplary embodiments, the data control signal DCTRL includes a horizontal start signal and a load signal, but is not limited thereto. In an exemplary embodiment, the data driver 140 includes an output buffer circuit 150 that outputs the data voltage DV to the data line DL. In some exemplary embodiments, the output buffer circuit 150 sequentially supplies the data voltage DV to the plurality of pixel rows PXR1, PXR2, … …, PXRN through the data line DL in the active period of the frame period, and supplies the reference voltage VREF for the mobility sensing operation to a selected pixel row among the plurality of pixel rows PXR1, PXR2, … …, PXRN through the data line DL and the sensing line SL in the vertical blank period or sensing period of the frame period. In some example embodiments, the data driver 140 may be implemented with one or more integrated circuits. In other exemplary embodiments, the data driver 140 and the controller 170 may be implemented with a single integrated circuit, which may be referred to as a timing controller embedded data driver (TED).

The sensing circuit 160 receives a sensing voltage SV from the plurality of pixels PX through the plurality of sensing lines SL and generates sensing data corresponding to the sensing voltage SV. In some exemplary embodiments, the sensing data includes mobility sensing data MSD corresponding to mobility values of the driving transistors DT of the plurality of pixels PX. Further, in some exemplary embodiments, the sensing data further includes threshold voltage sensing data representing threshold voltage values of the driving transistors DT of the plurality of pixels PX. For example, as shown in fig. 4, for each channel CH, the sensing circuit 160 includes a sensing capacitor SC coupled to the channel CH and an analog-to-digital converter ADC for converting the sensing voltage SV into sensing data. However, the sensing circuit 160 is not limited to the manner depicted in FIG. 4. In some exemplary embodiments, as shown in fig. 1, the sensing circuit 160 is included in the data driver 140. However, the location of the sensing circuit 160 is not limited to the example of fig. 1. For example, the sensing circuit 160 may be implemented with a separate integrated circuit or may be included in the controller 170.

The controller 170, for example, a Timing Controller (TCON), receives input image data IDAT and a control signal CTRL. The input image data IDAT and the control signal CTRL may be received from an external host (e.g., a Graphics Processing Unit (GPU), a graphics card, etc.). In some exemplary embodiments, the control signal CTRL includes a vertical synchronization signal, a horizontal synchronization signal, an input data enable signal, and a main clock signal, but is not limited thereto. The controller 170 generates output image data ODAT, a data control signal DCTRL, and a scan control signal SCTRL based on the input image data IDAT and the control signal CTRL. The controller 170 may control the operation of the data driver 140 by supplying the output image data ODAT and the data control signal DCTRL to the data driver 140, and may control the operation of the scan driver 130 by supplying the scan control signal SCTRL to the scan driver 130.

In the OLED display device 100 according to the disclosed exemplary embodiment, the panel driver 120 selects one pixel row from among the plurality of pixel rows PXR1, PXR2, … …, PXRN, determines load data based on the input image data IDAT of the selected one pixel row, determines target mobility data TMD corresponding to the load data, generates mobility sensing data MSD by performing a mobility sensing operation on the selected one pixel row, compares the mobility sensing data MSD with the target mobility data TMD, and may adjust a panel current flowing through the display panel 110 based on the result of the comparison. In an exemplary embodiment, the panel current is a sum of driving currents flowing in the corresponding pixels PX due to the line receiving the first power supply voltage ELVDD and the line receiving the second power supply voltage ELVSS. However, the panel current is not limited to the sum, and may be calculated in another manner. Accordingly, in the OLED display device 100 according to the disclosed exemplary embodiment, the panel driver 120 controls the panel current by using the mobility sensing data MSD without a series resistor for sensing the panel current. In the disclosed exemplary embodiment, the panel driver 120 further includes a target mobility determination block 180 (e.g., a determination circuit) and a current control block 190 (e.g., a current control circuit). In some exemplary embodiments, as shown in fig. 1, the target mobility determination block 180 and the current control block 190 are included in the controller 170, but the locations of the target mobility determination block 180 and the current control block 190 are not limited to the example of fig. 1.

In the embodiment, the target mobility determination block 180 selects one pixel row on which the mobility sensing operation is to be performed from among the plurality of pixel rows PXR1, PXR2, … …, PXRN. In some exemplary embodiments, the target mobility determination block 180 calculates a plurality of pixel row load data of the plurality of pixel rows PXR1, PXR2, … …, PXRN based on the input image data IDAT of the plurality of pixel rows PXR1, PXR2, … …, PXRN, and selects one pixel row having the largest pixel row load data among the plurality of pixel row load data of the plurality of pixel rows PXR1, PXR2, … …, PXRN, as described below with reference to fig. 7 and 8. In other exemplary embodiments, the target mobility determination block 180 selects the uppermost pixel row PXR1 or the lowermost pixel row PXRN among the plurality of pixel rows PXR1, PXR2, … …, PXRN, as described below with reference to fig. 9 and 10. In other exemplary embodiments, as described below with reference to fig. 11 and 12, the target mobility determination block 180 sequentially selects the plurality of pixel rows PXR1, PXR2, … …, PXRN such that the selection of the one pixel row is changed every frame period. For example, the first pixel row PXR1 may be a pixel row selected during the first frame period, the second pixel row PXR2 may be a pixel row selected during the second frame period, and so on.

In an embodiment, the target mobility determination block 180 determines the load data based on the input image data IDAT of the selected one pixel row. In some exemplary embodiments, the target mobility determination block 180 calculates the load data by dividing the input image data IDAT of the selected one pixel row by the maximum image data of the selected one pixel row. For example, the load data may be calculated by dividing an average value or a sum of pixel data included in the input image data IDAT of one pixel row by an average value or a sum of pixel data included in the maximum image data. Here, the maximum image data may be line image data (or image data of one pixel line) including pixel data having a maximum gray level (e.g., 255 gray levels). For example, in the case where all the pixel data of the input image data IDAT of a selected one pixel row represents the maximum gray level, the target mobility determination block 180 generates the load data representing about 100% or exactly 100%. In another example, in the case where all the pixel data of the input image data IDAT of a selected one pixel row represents an intermediate gray level (e.g., 128 gray levels), the target mobility determination block 180 generates load data representing about 50% or exactly 50%. In yet another example, in a case where half of the pixel data of the input image data IDAT of the selected one pixel row represents the maximum gray level and the remaining half of the pixel data of the input image data IDAT of the selected one pixel row represents the minimum gray level (e.g., 0 gray level), the target mobility determination block 180 generates the load data representing about 50% or exactly 50%. In an exemplary embodiment, the gray levels of each pixel PX of a given pixel row are added together to produce a sum, the sum is divided by the number of pixels PX in the given pixel row to produce an average, and the average is divided by the maximum gray level to produce load data for the given pixel row.

The target mobility determination block 180 determines the target mobility data TMD corresponding to the load data. In some exemplary embodiments, as shown in fig. 2, in the case where the load data is smaller than the reference load data RLD (for example, representing about 30%), the target mobility determination block 180 causes the target mobility data TMD to increase as the load data increases. In an exemplary embodiment, the target mobility determination block 180 sets the target mobility data TMD to the maximum target mobility data MTMD corresponding to the reference load data RLD in the case where the load data is greater than or equal to the reference load data RLD. In this case, since the target mobility data TMD is limited to the maximum target mobility data MTMD, the panel current flowing through the display panel 110 is not excessively increased, and the power consumption of the OLED display device 100 may be reduced.

In some exemplary embodiments, as shown in fig. 1 and 3, the target mobility determination block 180 includes a target mobility storage block 185 (e.g., a memory device) storing a plurality of target mobility values TMD1, TMD2, TMD3, TMD4, and TMD5, the plurality of target mobility values TMD1, TMD2, TMD3, TMD4, and TMD5 corresponding to a plurality of load values, for example, about 1%, about 5%, about 10%, about 20%, and about 30%, respectively. The target mobility determining block 180 may determine the target mobility data TMD corresponding to the load data by using the target mobility storage block 185. For example, in the case where the load data represents a load value of about 10%, the target mobility determination block 180 may obtain a target mobility value TMD3 corresponding to the load value of about 10% from the target mobility storage block 185, and may generate the target mobility data TMD having the target mobility value TMD 3. Further, in some exemplary embodiments, the target mobility determination block 180 determines two load values adjacent to the load value represented by the load data among the plurality of load values, obtains two target mobility values corresponding to the two load values among the plurality of target mobility values TMD1, TMD2, TMD3, TMD4, and TMD5 from the target mobility storage block 185, and interpolates the target mobility data TMD from the two target mobility values. For example, in the case where the load data represents a load value of about 15%, the target mobility determining block 180 obtains two target mobility values TMD2 and TMD3 corresponding to two load values of about 10% and about 20% from the target mobility storage block 185, linearly interpolates the interpolated target mobility values from the two target mobility values TMD2 and TMD3, and generates the target mobility data TMD having the linearly interpolated target mobility values. Further, in some exemplary embodiments, an aging process of providing an aging signal (e.g., including the scan signals SS1 and SS2 and the data voltage DV) to the display panel 110 to enable the plurality of pixels PX to emit light may be performed to improve stability and reliability of the OLED display device 100 before the OLED display device 100 is sold, and the plurality of target mobility values TMD1, TMD2, TMD3, TMD4, and TMD5 stored in the target mobility storage block 185 may be mobility values (e.g., an average or sum of the mobility values) of the driving transistors DT included in any one pixel row measured by using the sensing circuit 160 before the aging process of the display panel 110 is performed. Accordingly, the plurality of target mobility values TMD1, TMD2, TMD3, TMD4, and TMD5 stored in the target mobility storage block 185 may correspond to the initial mobility characteristics of the driving transistor DT, but is not limited thereto.

In an embodiment, the sensing circuit 160 generates the mobility sensing data MSD corresponding to the mobility value (e.g., an average or sum of the mobility values) of the driving transistors DT of the plurality of pixels PX included in the selected one pixel row by performing a mobility sensing operation on the selected one pixel row. For example, as shown in fig. 4 and 5, for each channel CH, the data driver 140 may further include a first switch SW1 for selectively coupling the output buffer circuit 150 and the channel CH, a second switch SW2 for selectively coupling the sensing circuit 160 and the channel CH, a third switch SW3 for selectively coupling the channel CH and the data line DL, a fourth switch SW4 for selectively coupling the channel CH and the sensing line SL, and a fifth switch SW5 for selectively coupling the sensing line SL and the line of the second reference voltage VREF 2. In order to perform a mobility sensing operation on each pixel PX included in a selected one of the pixel rows, the data driver 140 may respectively supply first and second reference voltages VREF1 and VREF2 to first and second electrodes of the storage capacitor CST as the reference voltage VREF, and may detect a change in the voltage V _ SL of the sensing line SL or a change in the sensing voltage SV during a desired or predetermined sensing time ST by using the sensing circuit 160.

For example, as shown in fig. 5, a mobility sensing operation for a selected one pixel row may be performed in a sensing period SP of each frame period. In some exemplary embodiments, the sensing period SP of each frame period corresponds to the vertical blank period VBP between the active periods. In an embodiment, the sensing period SP includes a first period P1, a second period P2, and a third period P3, the reference voltage VREF is applied to the plurality of pixels PX included in the selected one pixel row in the first period P1, the plurality of pixels PX are coupled to the sensing circuit 160 through the plurality of sensing lines SL in the second period P2, and the third period P3 includes a sensing time ST in which mobility characteristics of the driving transistors DT of the plurality of pixels PX are sensed. In an embodiment, the third period P3 is longer than the first period P1 or the second period P2. In the embodiment, the third period P3 is longer than the sum of the first period P1 and the second period P2.

In the first period P1, the first switch SW1 is turned on, the second switch SW2 is turned off, the third switch SW3 is turned on, the fourth switch SW4 is turned off, and the fifth switch SW5 is turned on. Accordingly, each channel CH may be coupled to the output buffer circuit 150 and the data line DL, and the second reference voltage VREF2 may be applied to the sensing line SL. Further, the first scan signal SS1 having a turn-on level may be applied, the second scan signal SS2 having a turn-on level may be applied, and the output buffer circuit 150 may output the first reference voltage VREF1 as the voltage DL _ V of the data line DL. Accordingly, the first switching transistor ST1 is turned on, and the first reference voltage VREF1 is applied to the first electrode of the storage capacitor CST. In addition, the second switching transistor ST2 is turned on, and the second reference voltage VREF2 is applied to the second electrode of the storage capacitor CST. Accordingly, the storage capacitor CST stores a voltage difference between the first reference voltage VREF1 and the second reference voltage VREF2 as the reference voltage VREF.

In the second period P2, the first switch SW1 is turned off, the second switch SW2 is turned on, the third switch SW3 is turned off, the fourth switch SW4 is turned on, and the fifth switch SW5 is maintained in an on state. Thus, each channel CH may be coupled to sensing circuitry 160 and sense line SL.

In the third period P3, the fifth switch SW5 is turned off. Accordingly, the second reference voltage VREF2 is not applied to the sensing line SL, and the voltage V _ SL or the sensing voltage SV of the sensing line SL is gradually increased from the initial voltage V0 to the second voltage V2 through the turned-on driving transistor DT based on the voltage difference between the first reference voltage VREF1 and the second reference voltage VREF2 stored in the storage capacitor CST. In an embodiment, the initial voltage V0 corresponds to the second reference voltage VREF2, and the second voltage V2 is a lower voltage than the first reference voltage VREF 1. In an example, the first reference voltage VREF1 is about 5V and the second reference voltage VREF2 is about 2V. However, the first and second reference voltages VREF1 and VREF2 are not limited to these values. The sensing circuit 160 may detect a change in the voltage V _ SL of the sensing line SL or a change in the sensing voltage SV during the sensing time ST. For example, the sensing circuit 160 may measure the first voltage V1 as the voltage V _ SL of the sensing line SL at a first time point T1, may measure the second voltage V2 as the voltage V _ SL of the sensing line SL at a second time point T2 after the sensing time ST from the first time point T1, and may generate the mobility sensing data MSD based on a change in the sensing voltage SV or a voltage difference between the first voltage V1 and the second voltage V2. In some exemplary embodiments, the sensing circuit 160 generates the mobility sensing data MSD by using the following equation 1, I ═ C × (V2-V1)/(T2-T1) (equation 1).

In equation 1, V1 is a first voltage, V2 is a second voltage, T1 is a first time point, T2 is a second time point, C is the capacitance of sensing capacitor SC (and the parasitic capacitor of sensing line SL), and I is the current of sensing line SL. The current I of the sensing line SL may correspond to the mobility of the driving transistor DT, and thus, the sensing circuit 160 may generate mobility sensing data MSD representing the current I of the sensing line SL calculated using equation 1 above.

In an exemplary embodiment, in the sensing period SP of each frame period, the panel driver 120 applies the reference voltage VREF to the plurality of pixels PX included in the selected one pixel row, detects a sensing voltage variation of the plurality of sensing lines SL coupled to the plurality of pixels PX during the sensing time ST within the sensing period SP by using the sensing circuit 160, and generates the mobility sensing data MSD based on the sensing voltage variation. Although fig. 4 illustrates an example of each pixel PX of the display panel 110 and the data driver 140 performing the mobility sensing operation, the configuration of the data driver 140 and the pixels PX according to the exemplary embodiment is not limited to the example of fig. 4. Further, although fig. 5 illustrates an example of timings of switches, signals, and voltages for describing a mobility sensing operation, the mobility sensing operation of the OLED display device 100 according to an exemplary embodiment is not limited to the example of fig. 5.

Referring again to fig. 1, the current control block 190 compares the mobility sensing data MSD and the target mobility data TMD, and may adjust a panel current flowing through the display panel 110 according to a result of the comparison of the mobility sensing data MSD and the target mobility data TMD. In an exemplary embodiment, the current control block 190 reduces the panel current when the mobility sensing data MSD is greater than the target mobility data TMD and increases the panel current when the mobility sensing data MSD is less than the target mobility data TMD. In some example embodiments, in the case where the mobility sensing data MSD is greater than the target mobility data TMD, the current control block 190 may generate the output image data ODAT provided to the data driver 140 by reducing the input image data IDAT of the plurality of pixel rows PXR1, PXR2, … …, PXRN such that the data voltage DV applied to the plurality of pixel rows PXR1, PXR2, … …, PXRN is reduced. For example, the current control block 190 may generate the output image data ODAT by multiplying the pixel data included in the input image data IDAT by a coefficient smaller than 1. For example, the coefficient may be a value greater than 0 and less than 1. Accordingly, the data voltage DV applied to the plurality of pixels PX may be reduced based on the output image data ODAT generated by reducing the input image data IDAT, and the driving current or the panel current of the driving transistors DT of the plurality of pixels PX may be reduced based on the reduced data voltage DV. Further, in the case where the mobility sensing data MSD is smaller than the target mobility data TMD, the current control block 190 may generate the output image data ODAT supplied to the data driver 140 by increasing the input image data IDAT of the plurality of pixel rows PXR1, PXR2, … …, PXRN such that the data voltage DV applied to the plurality of pixel rows PXR1, PXR2, … …, PXRN is increased. For example, the current control block 190 may generate the output image data ODAT by multiplying the pixel data included in the input image data IDAT by a coefficient greater than 1. Accordingly, the data voltage DV applied to the plurality of pixels PX may be increased based on the output image data ODAT generated by increasing the input image data IDAT, and the driving current or the panel current of the driving transistors DT of the plurality of pixels PX may be increased based on the increased data voltage DV.

If the temperature of the display panel 110 increases, the luminance or panel current of the display panel 110 may increase. In addition, if the luminance or the panel current of the display panel 110 increases, the temperature of the display panel 110 may increase. Accordingly, the brightness or the panel current of the display panel 110 may be proportional to the temperature of the display panel 110. Fig. 6 shows an example of the mobility (on a logarithmic scale) of each driving transistor DT according to the temperature (on a logarithmic scale) of the display panel 110. As shown in fig. 6 (e.g., the left half of fig. 6), in the impurity diffusion region 200 having a relatively low temperature, the mobility of the driving transistor DT increases as the temperature of the display panel 110 increases. Accordingly, not only the panel current but also the mobility of the driving transistor DT may be proportional to the temperature of the display panel 110, and thus, the mobility of the driving transistor DT may be proportional to the panel current and the panel temperature. Accordingly, in the OLED display device 100 according to the disclosed exemplary embodiment, even if the present panel current is directly sensed without using a series resistor coupled to the display panel 110, the present panel current may be inferred from the mobility sensing data MSD representing the mobility of the driving transistor DT. Further, in order to enable the mobility sensing data MSD corresponding to the present panel current to become the target mobility data TMD corresponding to the target panel current, the OLED display device 100 may adjust the panel current by adjusting the data voltage DV. Accordingly, the OLED display device 100 may control the panel current to be substantially constant with respect to substantially the same load data. Accordingly, the OLED display device 100 can perform a constant current control operation without a series resistor. However, as shown in fig. 6 (e.g., the right half of fig. 6), in the lattice scattering region having a relatively high temperature, the mobility of the driving transistor DT decreases as the temperature of the display panel 110 increases. In the disclosed exemplary embodiment, in the case where the driving transistor DT of the display panel 110 has mobility characteristics in a lattice scattering region, the panel driver 120 increases the panel current when the mobility sensing data MSD is greater than the target mobility data TMD and decreases the panel current when the mobility sensing data MSD is less than the target mobility data TMD.

The constant current control operation may be performed by sensing the current panel current using a series resistor coupled to the display panel 110. The panel current may be controlled by comparing the present panel current with a constant target panel current. However, in this case, a series resistor having a high resistance is required to sense the panel current, and thus, the cost of manufacturing the OLED display device may increase. In addition, the power consumption of the OLED display device may increase due to the series resistor. However, as described above, in the OLED display device 100 according to the disclosed exemplary embodiment, the panel current is controlled by using the mobility sensing data MSD without a series transistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 100 may be reduced.

In the disclosed exemplary embodiment, the panel driver 120 further includes an overcurrent protection circuit 195 for detecting an overcurrent of the display panel 110 and for stopping the operation of the OLED display device 100. In an embodiment, when the mobility sensing data MSD reaches more than the target mobility data TMD than the turn-off reference amount during a plurality of frame periods (e.g., 60 frame periods) corresponding to the turn-off reference time, the overcurrent protection circuit 195 determines that an overcurrent occurs in the display panel 110 and stops the operation of the OLED display device 100. For example, if the overcurrent protection circuit 195 determines that the mobility sensing data MSD exceeds the target amount by more than the reference amount within a certain number of frame periods, the current control block 190, the controller 170, or the panel driver 120 may perform an operation to reduce the overcurrent. For example, the operations may include: the controller 170 no longer outputs the output image data ODAT; the controller 170 provides a scan control signal SCTRL informing the scan driver 130 not to activate any scan signal; or the panel driver 120 blocks power to the data driver 140, the scan driver 130, and/or the display panel 110. In some exemplary embodiments, as shown in fig. 1, the overcurrent protection circuit 195 may be included in the controller 170 or the current control block 190, but the location of the overcurrent protection circuit 195 is not limited to the example of fig. 1.

When the series resistor is included in the OLED display device, it is determined that an overcurrent occurs when a present panel current sensed using the series resistor is greater than a reference panel current that is constant regardless of load data. However, when the series resistor is used in a case where the load data represents a low load, an overcurrent may not be detected. However, in the OLED display device 100 according to the disclosed exemplary embodiment, since the overcurrent is detected by using the mobility sensing data MSD and the target mobility data TMD corresponding to the load data, the overcurrent can be accurately detected even if the load data represents a low load.

As described above, in the OLED display device 100 according to the disclosed exemplary embodiment, the panel driver 120 selects one pixel row from among the plurality of pixel rows PXR1, PXR2, … …, PXRN, determines load data based on the input image data IDAT of the selected one pixel row, determines target mobility data TMD corresponding to the load data, generates mobility sensing data MSD by performing a mobility sensing operation on the selected one pixel row, and adjusts a panel current by comparing the mobility sensing data MSD with the target mobility data TMD. Accordingly, in the OLED display device 100 according to the disclosed exemplary embodiment, the panel driver 120 controls the panel current by using the mobility sensing data MSD without a series resistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 100 may be reduced. Further, in the OLED display device 100 according to the disclosed exemplary embodiment, the panel driver 120 performs an overcurrent protection operation by using the mobility sensing data MSD. Therefore, in the OLED display device 100 according to the disclosed exemplary embodiment, the overcurrent protection operation may be normally performed even if the load data represents a low load.

Fig. 7 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment, and fig. 8 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 7.

Referring to fig. 1 and 7, in a method of operating an OLED display device 100 including a display panel 110 having a plurality of pixel rows PXR1, PXR2, … …, PXRN, a target mobility determination block 180 selects one pixel row from the plurality of pixel rows PXR1, PXR2, … …, PXRN (S310). In an exemplary embodiment, the target mobility determination block 180 calculates a plurality of pixel row load data of the plurality of pixel rows PXR1, PXR2, … …, PXRN based on the input image data IDAT of the plurality of pixel rows PXR1, PXR2, … …, PXRN (S320), and selects one pixel row having the largest pixel row load data among the plurality of pixel row load data of the plurality of pixel rows PXR1, PXR2, … …, PXRN (S330). For example, the target mobility determination block 180 may calculate a first load value of the first pixel row PXR1 from the input image data of only the first pixel row PXR1, calculate a second load value of the second pixel row PXR2 from the input image data of only the second pixel row PXR2, and if the first load value is higher than the second load value and other load values calculated for the remaining pixel rows, the target mobility determination block 180 may select the first pixel row PXR 1.

For example, as shown in fig. 8, the input image data IDAT corresponding to one frame period may include a plurality of pixel rows PXR1, PXR2, … …, a plurality of row image data LIDAT1, LIDAT2, … …, LIDATN of the PXRN, and the target mobility determination block 180 may calculate a plurality of pixel rows PXR1, PXR2, … …, a plurality of pixel row load data PXRLOAD1, PXRLOAD2, … …, PXRLOADN of the PXRN based on the plurality of row image data LIDAT1, LIDAT2, … …, LIDATN of the plurality of pixel rows PXR1, PXR2, … …, PXRN, respectively. For example, the target mobility determination block 180 may calculate each pixel row load data (e.g., PXRLOAD1) by dividing an average or sum of pixel data included in corresponding row image data (e.g., LIDAT1) by an average or sum of maximum image data or maximum row image data of one pixel row. Further, the target mobility determination block 180 may determine the largest pixel row load data among the plurality of pixel row load data PXRLOAD1, PXRLOAD2, … …, PXRLOADN, and may select one pixel row having the largest pixel row load data among the plurality of pixel rows PXR1, PXR2, … …, PXRN.

The target mobility determination block 180 may determine the payload data based on the input image data IDAT of the selected one pixel row (S340). For example, since one pixel row having the largest pixel row load data is selected, the target mobility determination block 180 may determine the largest pixel row load data among the plurality of pixel row load data PXRLOAD1, PXRLOAD2, … …, PXRLOADN as load data.

The target mobility determination block 180 determines the target mobility data TMD corresponding to the load data (S350). In an exemplary embodiment, in the case where the load data is less than the reference load data (e.g., RLD in fig. 2), the target mobility data TMD determined by the target mobility determining block 180 increases as the load data increases, and in the case where the load data is greater than or equal to the reference load data, the target mobility data TMD determined by the target mobility determining block 180 is determined as the maximum target mobility data (e.g., MTMD in fig. 2) corresponding to the reference load data.

The sensing circuit 160 generates mobility sensing data MSD corresponding to mobility values of driving transistors of a plurality of pixels included in the selected one pixel row by performing a mobility sensing operation on the selected one pixel row (S360).

The current control block 190 compares the mobility sensing data MSD and the target mobility data TMD (S370), and may adjust a panel current flowing through the display panel 110 according to the result of the comparison of the mobility sensing data MSD and the target mobility data TMD (S380). In the disclosed exemplary embodiment, the current control block 190 reduces the panel current when the mobility sensing data MSD is greater than the target mobility data TMD, and the current control block 190 increases the panel current when the mobility sensing data MSD is less than the target mobility data TMD. For example, to reduce the panel current, the current control block 190 may generate the output image data ODAT by reducing the magnitude of the input image data IDAT, and the data voltage DV applied to the plurality of pixel rows PXR1, PXR2, … …, PXRN is reduced based on the output image data ODAT. Further, in order to increase the panel current, the current control block 190 may generate the output image data ODAT by increasing the magnitude of the input image data IDAT, and the data voltage DV applied to the plurality of pixel rows PXR1, PXR2, … …, PXRN may be increased based on the output image data ODAT. Accordingly, in the method of operating the OLED display device 100 according to the disclosed exemplary embodiment, the panel current may be controlled by using the mobility sensing data MSD without a series transistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 100 may be reduced.

Fig. 9 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment, and fig. 10 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 9.

Referring to fig. 1 and 9, in a method of operating an OLED display device 100 including a display panel 110 having a plurality of pixel rows PXR1, PXR2, … …, PXRN, a target mobility determination block 180 selects an uppermost pixel row PXR1 (or a lowermost pixel row PXRN) from among the plurality of pixel rows PXR1, PXR2, … …, PXRN (S410). In some exemplary embodiments, as shown in fig. 10, the display panel 110 includes a power wiring 115 having a mesh structure to supply a first power supply voltage ELVDD (e.g., a high power supply voltage) to the plurality of pixels PX. The power wiring 115 is supplied with the first power supply voltage ELVDD at an upper portion and/or a lower portion. Accordingly, the temperature variation and/or the panel current variation of the uppermost pixel row PXR1 (or the lowermost pixel row PXRN) positioned corresponding to the upper portion (or the lower portion) of the power wiring 115 may be larger than those of the other pixel rows (e.g., PXR2, … …, etc.). Accordingly, the target mobility determination block 180 may select the uppermost pixel row PXR1 (or the lowermost pixel row PXRN) having the largest temperature variation and/or the largest panel current variation as one pixel row on which the mobility sensing operation is to be performed.

The target mobility determination block 180 determines the payload data based on the input image data IDAT of the uppermost pixel row PXR1 (or the lowermost pixel row PXRN) (S440), and determines the target mobility data TMD corresponding to the payload data (S450). The sensing circuit 160 generates mobility sensing data MSD by performing a mobility sensing operation on the uppermost pixel row PXR1 (or the lowermost pixel row PXRN) (S460). The current control block 190 compares the mobility sensing data MSD and the target mobility data TMD (S470), and may adjust a panel current flowing through the display panel 110 according to a result of the comparison of the mobility sensing data MSD and the target mobility data TMD (S480). Accordingly, in the method of operating the OLED display device 100 according to the disclosed exemplary embodiment, the panel current may be controlled by using the mobility sensing data MSD without a series resistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 100 may be reduced.

Fig. 11 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment, and fig. 12 is a diagram for describing an example of selecting one pixel row on which a mobility sensing operation is performed in the method of fig. 11.

Referring to fig. 1 and 11, in a method of operating an OLED display device 100 including a display panel 110 having a plurality of pixel rows PXR1, PXR2, … …, PXRN, a target mobility determination block 180 sequentially selects the plurality of pixel rows PXR1, PXR2, … …, PXRN such that selection of one pixel row on which a mobility sensing operation is to be performed is changed per frame period (S510). For example, as shown in fig. 12, each of the frame periods FP1, FP2, … …, FPN may include a vertical blank period VBP and an active period AP, and the panel driver 120 may perform a mobility sensing operation on one pixel row during a sensing period SP corresponding to the vertical blank period VBP. In an embodiment, all pixel rows of the display panel 110 sequentially receive corresponding data voltages during a single frame period. For example, during part of the frame period, only some of the pixel rows receive the data voltages. In an embodiment, a given pixel row receives a data voltage during the active period AP of a frame period and does not receive a data voltage during the vertical blank period VBP of the frame period. Also, the panel driver 120 may perform a mobility sensing operation on the first pixel row PXR1 in the sensing period SP of the first frame period FP1, and may perform a mobility sensing operation on the second pixel row PXR2 in the sensing period SP of the second frame period FP 2. In this way, the panel driver 120 may perform a mobility sensing operation on the nth pixel row PXRN in the sensing period SP of the nth frame period FPN, where N is an integer greater than 1. Accordingly, the target mobility determination block 180 may select N pixel rows PXR1, PXR2, … …, PXRN in N frame periods FP1, FP2, … …, FPN, respectively. In the N +1 th frame period, the first pixel row PXR1 may be selected again.

The target mobility determining block 180 determines the load data based on the input image data IDAT of the selected one pixel row (S540), and determines the target mobility data TMD corresponding to the load data (S550). The sensing circuit 160 generates mobility sensing data MSD by performing a mobility sensing operation on the selected one pixel row (S560). The current control block 190 compares the mobility sensing data MSD and the target mobility data TMD (S570), and may adjust a panel current flowing through the display panel 110 according to the result of the comparison of the mobility sensing data MSD and the target mobility data TMD (S580). In an exemplary embodiment, the current control block 190 adjusts the panel current in the next frame period (e.g., FP2) based on the result of the comparison in each frame period (e.g., FP 1). For example, the result of the comparison of the previous frame period may be used to adjust the panel current in the next frame period. In an exemplary embodiment, the current control block 190 adjusts the panel current in the next frame period or the N +1 th frame period based on the sum of the results of the comparisons in the N frame periods FP1, FP2, … …, FPN. For example, if N is 2 (i.e., based on the sum of the results of the comparisons in the two frame periods), a first comparison is performed for the first pixel row PXR1 during the first frame period FP1, a second comparison is performed for the second pixel row PXR2 during the second frame period FP2, and the sum of the results of the first and second comparisons is used to adjust the panel current during the third frame period. Further, the current control block 190 may adjust the panel current in the N +2 th frame period based on the sum of the results of the comparisons in the second frame period FP2 to the N +1 th frame period. For example, if N remains 2, a third comparison is performed for a third pixel row during a third frame period, and the sum of the results of the second comparison and the third comparison is used to adjust the panel current during a fourth frame period. Accordingly, in the method of operating the OLED display device 100 according to an exemplary embodiment, the panel current may be controlled by using the mobility sensing data MSD without a series transistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 100 may be reduced.

Fig. 13 is a flowchart illustrating a method of operating an OLED display device according to an exemplary disclosed embodiment.

Referring to fig. 1 and 13, in a method of operating an OLED display device 100 including a display panel 110 having a plurality of pixel rows PXR1, PXR2, … …, PXRN, a target mobility determination block 180 selects one pixel row to which a mobility sensing operation is to be performed from among the plurality of pixel rows PXR1, PXR2, … …, PXRN (S610), determines load data based on input image data IDAT of the selected one pixel row (S640), and determines target mobility data TMD corresponding to the load data (S650). The sensing circuit 160 generates mobility sensing data MSD by performing a mobility sensing operation on the selected one pixel row (S660). The current control block 190 compares the mobility sensing data MSD and the target mobility data TMD (S670). The overcurrent protection circuit 195 included in the current control block 190 selectively stops the operation of the OLED display device 100 according to whether the difference between the mobility sensing data MSD and the target mobility data TMD satisfies the turn-off reference time and the turn-off reference amount (S680 and S685). For example, if the difference is within a certain range for a certain amount of time, the operation of the OLED display device 100 is stopped. In the case where the difference between the mobility sensing data MSD and the target mobility data TMD does not satisfy the turn-off reference time and the turn-off reference amount (S680: no), the operation of the OLED display device 100 is not stopped. The current control block 190 adjusts the panel current flowing through the display panel 110 according to the result of the comparison of the mobility sensing data MSD and the target mobility data TMD (S690).

In the case where the difference between the mobility sensing data MSD and the target mobility data TMD satisfies the close reference time and the close reference amount (S680: yes) or in the case where the mobility sensing data MSD is greater than the target mobility data TMD by more than the close reference amount during a plurality of frame periods (e.g., 60 frame periods) corresponding to the close reference time, the overcurrent protection circuit 195 determines that an overcurrent occurs in the display panel 110 and stops the operation of the OLED display device 100 (S685). Therefore, in the OLED display device 100 according to the disclosed exemplary embodiment, since the overcurrent is detected by using the mobility sensing data MSD, the overcurrent can be accurately detected even though the load data represents a low load, and the overcurrent protection operation of the overcurrent protection circuit 195 can be normally performed.

Fig. 14 is a block diagram illustrating an electronic device including an OLED display device according to an exemplary disclosed embodiment.

Referring to fig. 14, an electronic device 1100 includes a processor 1110, a memory device 1120, a storage device 1130, an input/output (I/O) device 1140, a power supply 1150, and an OLED display device 1160. The electronic device 1100 may also include a number of ports for communicating with video cards, sound cards, memory cards, Universal Serial Bus (USB) devices, other electrical devices, and the like.

Processor 1110 may perform various computing functions or tasks. The processor 1110 may be an Application Processor (AP), a microprocessor, a Central Processing Unit (CPU), or the like. The processor 1110 may be coupled to other components via an address bus, a control bus, a data bus, and the like. Further, in some example embodiments, the processor 1110 may also be coupled to an expansion bus, such as a Peripheral Component Interconnect (PCI) bus.

The memory device 1120 may store data for operation of the electronic device 1100. For example, the memory device 1120 may include at least one non-volatile memory device, such as an Erasable Programmable Read Only Memory (EPROM) device, an Electrically Erasable Programmable Read Only Memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a Resistive Random Access Memory (RRAM) device, a Nano Floating Gate Memory (NFGM) device, a polymer random access memory (popram) device, a Magnetic Random Access Memory (MRAM) device, a Ferroelectric Random Access Memory (FRAM) device, etc., and/or at least one volatile memory device, such as a Dynamic Random Access Memory (DRAM) device, a Static Random Access Memory (SRAM) device, a mobile dynamic random access memory (mobile DRAM) device, etc.

The storage device 1130 may be a Solid State Drive (SSD) device, a Hard Disk Drive (HDD) device, a CD-ROM device, or the like. The I/O devices 1140 may be input devices (such as keyboards, keypads, mice, touch screens, etc.) and output devices (such as printers, speakers, etc.). The power supply 1150 may provide power for the operation of the electronic device 1100. OLED display device 1160 may be coupled to the other components by a bus or other communication link.

In the OLED display device 1160 according to the disclosed exemplary embodiment, one pixel row is selected from a plurality of pixel rows, load data is determined based on input image data of the selected one pixel row, target mobility data corresponding to the load data is determined, mobility sensing data is generated by performing a mobility sensing operation on the selected one pixel row, and a panel current may be adjusted by comparing the mobility sensing data and the target mobility data. Accordingly, the OLED display device 1160 may control the panel current by using the mobility sensing data without a series resistor for sensing the panel current, and thus, the cost and power consumption of the OLED display device 1160 may be reduced. Also, in some exemplary embodiments, the OLED display device 1160 may perform an overcurrent protection operation by using the mobility sensing data.

The inventive concept can be applied to any electronic device 1100 including the OLED display device 1160. For example, the inventive concept may be applied to a Television (TV), a digital TV, a 3D TV, a smart phone, a wearable electronic device, a tablet computer, a mobile phone, a Personal Computer (PC), a home appliance, a laptop computer, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), a digital camera, a music player, a portable game controller, a navigation device, and the like.

Although a few exemplary embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings. Accordingly, all such modifications are intended to be included within the scope of the present inventive concept.