KR100944494B1 - Passive matrix organic light emitting diode driving circuit and driving method - Google Patents

Abstract

The present invention discloses a PMOLED driving circuit and a driving method capable of reducing the power consumption by reducing the magnitude of the driving current and extending the life of the PMOLED. The PMO LED driving circuit includes a PWM computing device and a line driver. The PWM calculating device calculates a scale factor using current frame data, and calculates a variable current amount of a variable current device and a crystal unit connection time used to switch the variable current device using the scale factor. The line driver drives the panel by processing horizontal and vertical line information of the panel included in the frame data in response to the variable current amount and the correction unit connection time. The line driver drives two horizontal lines of the panel into one and drives them in three stages. The PMOLED driving method includes a scale factor calculation step, a variable current amount and a correction unit connection time calculation step, and a PMOLED driving step.

PMOLED, PWM, Driver Circuit, Driver, Scale Factor

Description

Passive matrix organic light emitting diode driving circuit and driving method

The present invention relates to a driving circuit and a driving method of a PMOLED, and more particularly, to a PMOLED driving circuit and a driving method capable of reducing power consumption and extending the life of the PMOLED by reducing the magnitude of the driving current.

Recently, as a new flat panel display technology, displays using organic light emitting diodes (OLEDs) have been actively studied around the world. OLED not only has excellent display characteristics but also has a simple structure and is easy to manufacture. In addition, OLEDs can be manufactured on plastic substrates as well as glass substrates, which enables the manufacture of flexible displays that are not only thin and light but also can be unfolded when needed.

OLED displays are classified into passive matrix (PM) and active matrix (AM) according to the driving method of the device. Passive OLED (PMOLED) has a simple structure that forms an organic EL pixel at the intersection of the anode and cathode, and active OLED (AMOLED) has a TFT (Thin Film Transistor) in each pixel. Since PMOLED allows the selected OLED to emit light with high luminance for a short time, the instantaneous luminance should be higher as the resolution is increased.

1 is a schematic diagram of a display implemented with PMOLED.

Referring to FIG. 1, the display is composed of m (m is an integer) rows (R, R1 to Rm) and n (n is an integer) columns (Clumn, C1 to Cn), so both are mxn (m and n are integers). OLEDs. The P-type electrode of each OLED is connected to one of the current source and the ground voltage (GND) through the corresponding switch, and the N-type electrode is also connected to the scan-off voltage (Vscanoff) and the ground voltage (GND) through the corresponding switch. Will be connected to one of The n _PMOLEDs included in one row are driven during the row scan time (T _rowscan ). When the pixels included in the subsequent rows are sequentially driven and finally driven for m rows, a single screen of the panel using _PMOLEDs is driven. The display for is completed.

The amount of current supplied from the current source shown in FIG. 1 is all the same. The N-type electrodes of the _PMOLEDs included in the row to supply the energy corresponding to the video data during the row scan time T _rowscan are connected to the ground voltage GND so that current can flow from the current source to the ground voltage GND. do. At this time, since the N-type electrodes of the PMOLEDs arranged in the other row are all connected by the scan-off voltage Vscanoff, the current path from the current source to the ground voltage GND is not formed in these PMOLEDs.

2 shows the scan time of PMOLED.

Referring to FIG. 2, since the row scan time (T _rowscan ) is required to drive n _PMOLEDs included in one row, the frame scan time (T _frame ) required to display one frame, that is, one screen is a row. It is the product of the scan time (T _rowscan ) and the total number of rows (m) (mx T _rowscan ). Increases possible to 0 (zero) units of connection time (T _PWM) from the units of the line scan time (T _rowscan) and the maximum time is the maximum multiplication of the variable parameters (PWMMAX) and the unit connection time _{(T PWM) (PWMMAX x T} PWM ) Here, the unit connection time (T _PWM ) means the minimum unit connection time when the current source supplying a constant magnitude of current (I _d ) is connected to the P-type electrode of the PMOLED, and the maximum variable variable (PWMMAX) is an integer. Here, 0 (zero), which is the shortest time, means that the P-type electrode of PMOLED is continuously connected to the ground voltage (GND) during the row scan time (T _rowscan ), so that no current is supplied from the current source, and the longest time is PMOLED. This means that the P-type electrode is continuously connected to the current source for the row scan time T _rowscan . Referring to FIG. 2, the time for connecting the current source to the P-type electrode of PMOLED can be adjusted from 0 to PWMMAX x T _PWM according to the data value of the pixel.

As the resolution of the PMOLED panel increases, the number of rows (m) and the number of columns (n) increase, but the frame scan time (T _frame ) cannot be increased due to flicker and should be reduced. Here, the flicker phenomenon is a phenomenon in which the flicker of light is felt by the user because the intensity of light emitted from the panel screen is not constant and changes periodically with time.

Scanning time is reduced, but to achieve the same brightness as before, the amount of current supplied from the current source must be increased, which is not only the power consumed by PMOLED, The drawback is the rapid increase in power consumed by devices other than PMOLED. Increasing power consumption can also lead to a reduction in the lifetime of power-consuming devices.

The technical problem to be solved by the present invention is to provide a PMO LED drive circuit which enables the use of a high resolution and high capacity PMO LED panel by reducing power consumption and thus increasing the lifetime of the PMO LED.

Another technical problem to be solved by the present invention is to provide a PMO LED driving method which enables the use of a high resolution and high capacity PMO LED panel by reducing power consumption and thus increasing the lifetime of the PMO LED.

The PMOLED driving circuit according to the present invention for achieving the above technical problem includes a PWM operation device and a line driver. The PWM calculating device calculates a scale factor using current frame data, and calculates a variable current amount of a variable current device and a crystal unit connection time used to switch the variable current device using the scale factor. The line driver drives the panel by processing horizontal and vertical line information of the panel included in the frame data in response to the variable current amount and the correction unit connection time. The line driver drives two horizontal lines of the panel into one and drives them in three stages.

According to another aspect of the present invention, there is provided a PMOLED driving method including a scale factor calculation step, a variable current amount and correction unit connection time calculation step, and a PMOLED driving step. The scale factor calculation step calculates a scale factor using current frame data. In the calculating of the variable current amount and the correction unit connection time, the correction unit connection time is used to determine the time when the variable current amount supplied by the variable current and the variable current amount are supplied to the PMOLED using the scale factor. The PMOLED driving step drives the panel in units of two lines by using the variable current amount, the crystal unit connection time, and the frame data. Each of the two panel lines is driven in three steps.

The present invention has the advantage of enabling the use of a high resolution and large capacity PMOLED panel by reducing power consumption and thus increasing the lifetime of the PMOLED.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 illustrates the amount of scan time and current that illustrates the concept of the present invention.

The _{uppermost part} of FIG. 3 shows each row scan time T _rowscan scanning m rows included in one screen, that is, the frame scan time T _frame . The 4th, 5th, m- _2th and mth row scan times T _rowscan have the maximum scan time, but the row scan times T _rowscan of the remaining rows have a scan time less than the maximum row scan time. Therefore, there is a long and short time gap between each row scan time (T _rowscan ). This time interval is an operation standby time in which no operation is performed. In the present invention, this time interval is used to increase the time that the current is supplied instead of reducing the magnitude of the current supplied from the current source. To supply current. In this case, it is natural that the life of the PMOLED is increased compared to the PMOLED using the conventional driving method by decreasing the magnitude of the current.

In the center of FIG. 3, each row scan time shown in the upper portion is closely adhered to each other to easily distinguish the margin time T _s , which is the total time interval included in the frame scan time T _frame . At this time, if the magnitude (Id) of the current supplied from the current source is the same as in the conventional case, it can be seen that the time equal to a certain spare time T _s of the frame scan time T _frame is discarded.

The lower part of FIG. 3 shows that the current Id 'supplied from the current source is increased by using the margin time T _s , and the row scan time is increased to apply to each PMOLED instead of reducing (Id>Id'). Explain the concept of equalizing energy. The increase in row scan time means that the width of each pulse signal representing the scan time is longer than the corresponding pulse signal representing the row scan time shown in the upper and center portions of FIG.

)를 의미한다. 이렇게 정의된 스케일팩터를 이용하여 가변전류기로부터 공급받는 전류량 및 상기 전류를 해당 PMOLED에 흐르게 하는 시간을 결정한다. 여기서 PWM 클럭은 단위연결시간(T_PWM)에 곱해지는 가변변수의 수에 대응되며 최대가변변수(PWMMAX)에 할당된 수가 최대 PWM 클럭개수가 된다. 따라서 최대가변변수(PWMMAX)가 255라면 최대 PWM 클럭개수도 255가 된다. 최대가변변수(PWMMAX)가 적용된 화소(picture element)는 최대의 밝기를 디스플레이하게 될 것이다. In the present invention, in order to utilize the spare time T _s shown in FIG. 3, a scale factor is defined and used. The scale factor is a ratio of the maximum number of PWM clocks (N _total ) used to implement one screen and the maximum number of PWM clocks (N ' _total ) for processing the frame data (

) Means. The scale factor thus defined is used to determine the amount of current supplied from the variable current device and the time for the current to flow in the PMOLED. Here, the PWM clock corresponds to the number of variable variables multiplied by the unit connection time (T _PWM ), and the number assigned to the maximum variable variable (PWMMAX) becomes the maximum number of PWM clocks. Therefore, if the maximum variable variable (PWMMAX) is 255, the maximum number of PWM clocks is also 255. The picture element to which the maximum variable variable PWM is applied will display the maximum brightness.

4 shows a modified unit connection time T ' _PWM corresponding to an increased row scan time.

Referring to FIG. 4, it can be seen that the modified unit connection time (T ' _PWM ) is increased compared to the conventional unit connection time (T _PWM ) shown in FIG. 2 (T' _PWM > T _PWM ). This is because the extra time T _s was discarded in the crystal unit connection time T ' _PWM .

As already mentioned in the description of FIGS. 3 and 4, in the present invention, the free time T _s is calculated for each frame, the calculated free time T _s is converted into a scale factor, and then the variable current source. Adjust the amount of current supplied from the line and the row scan time to receive the current from the variable current source. The spare time T _s can be obtained by preprocessing each frame data. Therefore, in order to apply the present invention, a variable current source capable of varying the value of the output current must be used, not a fixed current source that supplies a fixed current value.

5 shows a 4 x 4 pixel array.

Referring to FIG. 5, assuming that the brightness of a pixel can be varied from 0 to 255 steps, 1024 (= 4 × 256) PWM clocks will be required to implement the total brightness that can be expressed in four rows. Here, 255 becomes the above-mentioned maximum variable variable (PWMMAX), so the number of PWM clocks is 256. However, as a result of preprocessing the current frame data, assuming that the brightness of the second pixel is the largest at 100 in the first row and the brightness at the largest brightness in the second to fourth rows is 200, 150, and 250, respectively. To achieve brightness, 700 (= 100 + 200 + 150 + 250) PWM clocks are required. As already defined, the scale factor is about 0.7 (700/1020), which is the ratio of the number of PWM clocks corresponding to the maximum brightness that can be realized and the number of PWM clocks corresponding to the total brightness of PMOLED of each row included in the current frame data. do.

The PMOLED driving circuit according to the present invention calculates the amount of current that can be reduced and the scan time that can be increased by using the scale factor obtained from the above calculation. As described above, in the present invention, in addition to utilizing the modified scan time by using the spare time T _s , two rows (horizontal lines) are not performed as a single row unit even when driving a pixel, that is, a PMOLED. ) Into one and run for three steps.

First, prior to a detailed description of the present invention, an S matrix to be used in the following description is defined.

Suppose that one screen of data to be displayed in PMOLED is a matrix of size m ㅧ n and each element is d _{i, j} . The element s _{i, j} of the new S matrix is defined as in Equation 1. . Where variables i and j denote rows and columns, respectively.

The reason why min is used for the S determinant is that the calculation is performed based on a small value among the elements included in the S matrix. This part will be described in detail below.

6 illustrates a three-step PMOLED driving method according to the present invention.

Referring to FIG. 6, two PMOLEDs included in the j column of the i-row of the new S matrix during the three-step driving process show currents flowing from the variable current source to the PMOLED. Although there are n columns in the i row, PMOLED disposed in the j column, one of them, will be described for convenience of description.

Here, assuming that the variable i is an odd number, data (d _{i, j} , d _{i + 1, j} ) are three driving stages (P _all , P _o ,) in the two PMOLEDs above and below one bundle. Divided by P _e ).

In the first driving step P _{all ,} energy S _{i, j} corresponding to data having a smaller brightness among two data d _{i, j} , d _{i + 1, j} associated with two PMOLEDs is It is delivered simultaneously to two PMOLEDs. That is, two data Data to size is to be transmitted to the PMOLED at the bottom of the data (d _{i, j)} to be transmitted to the PMOLED at the top of (d _{i, j,} d _{i + 1, j)} (d _{i + 1, j} ) is smaller than the size (d _{i, j} <d _{i + 1, j} ), the energy corresponding to the data (d _{i, j} ) to be transmitted to the upper PMOLED first driving step (P _all ) in common to the bottom and top PMOLEDs. Therefore, the term min is used in Equation 1. At this time, since the energy corresponding to the brightness of the relatively small size has already been transmitted, it is necessary to supply more current to the PMOLED to deliver the energy corresponding to the data (d _{i, j} ) representing the brightness of the relatively smaller size. Disappear. At this time, the two variable current sources I ' _j1 and I' _j2 are combined in parallel to supply twice the current that can be supplied by one variable current source to the P-type electrodes of the two PMOLEDs, and the N-type electrode is grounded. It is connected to the voltage GND.

In the second driving stage (P _o ), only one PMOLED of two PMOLEDs is selectively applied, and the energy already supplied in the first driving stage (P _all ) among the energy corresponding to the brightness to be ultimately supplied to the PMOLED Supply a current to compensate for the difference (d _{i, j} - _{Si, j} ). 6 illustrates a case in which an additional current is supplied to the PMOLED located above. At this time, the first switch SW _j1 is opened so that the first current source I ' _j1 does not affect the operation of the circuit any more, but since the second switch SW _j2 is shorted, the other current source I ' _j2 ) continues to supply current. At this time, the upper PMOLED N-type electrode is connected to the ground voltage GND to transfer the current supplied from the second current source I ' _j2 to the element, but the lower-side PMOLED N-type electrode has the scan-off voltage Vscanoff. Because it is connected to, no further current flows through the PMOLED below.

In the third driving stage (P _e ), the energy corresponding to the brightness that is ultimately to be supplied to the other PMOLED of the two PMOLEDs from the energy already supplied in the first driving stage (P _all ) (d _{i + 1 , j} -S _{i, j} ) to supply current. 6 illustrates a case where an additional current is supplied to the PMOLED below. At this time, the two, as in the second driving step (P _o), the first current source (I _'j1) is not so adversely affect the further operation is opened, and one of the current source (I' _j2) will continue the supply of electric current do. At this time, the lower PMOLED is connected to the ground voltage GND and the N-type electrode transfers the current supplied from the second current source I ' _j2 to the element, but the N-type electrode of the upper PMOLED is the scan-off voltage Vscanoff. Because no more current flows through the PMOLED above.

In the above description, for convenience of description, two _PMOLEDs included in two rows are described as being driven, but in practice, 2n _PMOLEDs included in two rows are simultaneously driven within a row scan time T _rowscan .

If all of the energy corresponding to all of the data (d _{i, j} ) to be transferred to the upper PMOLED in the first driving stage (P _all ) is transferred in common, in a later stage, it is necessary to supply further current to the upper PMOLED. There is no need to supply the current corresponding to the energy corresponding to the difference between the brightness data already transmitted and the data to be ultimately transmitted only to the PMOLED below.

)는 수학식 2와 같이 표시할 수 있다. Maximum number of PWM clocks to process the current frame data (

) May be expressed as in Equation 2.

The first term on the right side of the equation is the total number of PWM clocks used in the first driving stage (P _all ), and the second term is the PWM clock used in the second and third driving stages (P _o , P _e ). Will be the total number.

Since the product of the unit connection time (T _PWM ) and the number of PWM clocks (N _t = mx PWMMAX) must be constant, the modified unit connection time (T ' _PWM ) according to the present invention and the variable current (I' _d ) flowing in the PMOLED at this time. May be expressed as in Equation 3.

)감소한 새로운 전류량(I'_d)을 공급하는 가변전류원을 이용하여 각 화소를 구동한다. Referring to Equation 3, compared to the conventional amount of current I _d , the ratio of the number of PWM clocks, that is, the scale factor (

Each pixel is driven by using a variable current source that supplies a reduced new current amount I ' _d .

At this time, the number of PWM clocks in each of the three driving stages (Pall, Po, Pe) is max (s _{i, 1} , ..., s _{i, n} ) and max (d _{i, 1} -s _, respectively, as shown in FIG. _{i, 1} , ..., d _{i, n} -s _{i, n} ), max (d _{i + 1,1} -s _{i + 1,1} , ..., d _{i + 1, n} -s _{i + 1, n} ) do.

In the first driving stage (Pall), since the current flows to the two PMOLEDs separately, the current flowing through each PMOLED is supplied to the PMOLED by dividing the total current supplied from the variable current source in half so that the switch is set with one more variable current source. Use the sum of the currents output from the two current sources.

7 is a block diagram of a PMOLED driving circuit according to the present invention.

Referring to FIG. 7, the PMOLED driving circuit 700 includes a PWM operation unit 710 and a line driver 720.

The PWM operation unit 710 calculates the scale factor S / F using the current frame data and uses the scale factor S / F to determine the variable current amount I _{'d of} the variable current device and the variable current device. Compute the crystal unit connection time (T ' _PWM ) used to switch.

)인 스케일팩터(S/F)를 연산한다. 전류량 연산장치(712)는 스케일팩터(

)와 기본 전류량(I_d)의 곱(I_d x

)으로 결정되는 가변전류량(I'_d)을 연 산한다. 단위연결시간 연산장치(713)는 기본 단위연결시간(T_PWM)을 스케일팩터(

)로 나눈 값(T_PWM x

)으로 결정되는 수정단위연결시간(T'_PWM)을 연산한다. The PWM calculator 710 includes a scale factor calculator 711, a current amount calculator 712, and a unit connection time calculator 713. The scale factor calculator 711 is a ratio of the maximum number of PWM clocks (N _total ) of one screen and the maximum number of PWM clocks (N ' _total ) for processing current frame data (

Calculate the scale factor (S / F). Current amount calculator 712 is a scale factor (

) And the product of the primary current (I _d), (I _d x

Calculate the variable amount of current (I ' _d ) determined by. The unit connection time calculation unit 713 calculates the basic unit connection time (T _PWM ) and scale factor (

Divided by) (T _PWM x

Calculate the crystal unit connection time (T ' _PWM ) determined by).

6 and 7, the line driver 720 is a horizontal line (row) and a vertical line of the panel included in the frame data in response to the variable current amount I ' _d and the correction unit connection time T' _PWM . The first variable current (I ' _j1 ), the second variable current (I' _j2 ), the first switch (SW _j1 ) and the first to drive the panel by processing the line (column) information to drive the vertical line 2 switches SW _j2 are provided.

One terminal of the first variable current device I ' _j1 and one terminal of the second variable current device I' _j2 are connected to a power supply terminal to generate a current of the variable current amount I ' _d , respectively. The switch SW _j1 connects the other terminal of the first variable current device I ' _j1 and the other terminal of the second variable current device I' _j2 , and the second switch SW _j2 is connected to the first terminal. One of the other terminal of the switch SW _j1 and the ground voltage GND may be selected and connected to the P-type electrode of the PMOLED.

A first switch (SW _j1) has three driving stages _{(P all, P o, P} e) first driving step (P _all) in the turn-on (Turn on) and the other two driving stages (P _o, P _e) of In turn, all are turned off, and the second switch SW _j2 is turned on in _all three driving stages P _all , P _o , and P _e . The length of time to be turned on is determined using the crystal unit connection time (T ' _PWM ) and the frame data. Although the signal controlling the two switches SW _j1 and SW _j2 is not shown in consideration of the complexity of the drawing, the control of the switch will not be a problem as described above.

The line driver 720 is one of the essential features of the present invention by driving two horizontal lines (rows) of the panel into three driving stages (P _all , P _o , P _e ). 6 is described in the description.

8 is a signal flow diagram for a PMOLED driving method according to the present invention.

Referring to FIG. 8, the PMOLED driving method 800 includes a scale factor calculating step S810, a variable current amount and correction unit connection time calculating step S820, and a PMOLED driving step S930.

In the scale factor calculation step S810, a scale factor S / F for processing the current frame data is calculated, and a maximum PWM clock count N ′ _t for processing the current frame data is calculated. And calculating the scale factor S / F which is a ratio of the maximum PWM clock number N _t of one screen and the maximum PWM clock number N ′ _t for processing the current frame data (812). It is provided. Here, the maximum number of PWM clocks of one screen is a product of the number of horizontal lines of the panel and the maximum number of PWM clocks used to implement the pixel of maximum brightness, which is used for one horizontal line, and the maximum PWM clock for processing the frame data. The number is the sum of the maximum number of PWM clocks needed to implement the brightest pixel of each horizontal line.

In the calculating of the variable current amount and the correction unit connection time (S820), the correction unit connection time used to determine the variable current amount supplied by the variable current and the time when the variable current amount is supplied to the PMOLED is calculated using a scale factor. Multiplying the scale factor by the base current amount to calculate the variable current amount (821) and dividing the basic unit connection time by the scale factor to calculate the correction unit connection time (822).

The PMOLED driving step (S930) drives the panel in three steps by two lines by using a variable current amount, crystal unit connection time, and frame data, and is disposed above and below a vertical line corresponding to two horizontal lines. A first step 833 of supplying the two PMOLEDs with a current corresponding to a relatively low brightness among the brightnesses allocated to the two PMOLEDs, the brightness assigned to one PMOLED of the two PMOLEDs arranged up and down, and the A second step 834 of further supplying a current corresponding to the difference in brightness selected in the first step to the one PMOLED; and the brightness assigned to the other PMOLED of the two PMOLEDs arranged up and down and the first step The third step 835 is further provided to supply the current corresponding to the difference in brightness selected by the remaining PMOLED.

Referring to FIG. 6, in the first step 833, the current is supplied from the at least two current sources to the corresponding PMOLED, and in the remaining two steps 834 and 835, the current is supplied from the one current source to the corresponding PMOLED. Able to know.

Since the steps 831, 832, and 836 using the variable i in the third driving step 835 are commonly used in a signal flow chart, description thereof is omitted here.

In the above, the two consecutive horizontal lines (rows) are grouped together and driven, and the process of sequentially proceeding from the first row to the last row of the PMOLED panel has been described. However, the present invention can be extended to drive two or more rows together.

The PMOLED driving circuit and the driving method according to the present invention reduce the number of PWM clocks used to drive the entire screen by simultaneously driving two or more rows while utilizing the spare time that has conventionally been discarded. It reduces the magnitude of the drive current by the ratio and increases the connection time for connecting the variable current source to the PMOLED. Even if the size of the driving current is reduced, the switching time is increased by a reduced ratio, and thus the energy stored in the PMOLED is the same as in the conventional case. However, the life of the circuit is increased because the impact of the reduced current on the components of the circuit is greatly reduced. In particular, since the energy delivered to the parasitic element is proportional to the magnitude of the current, there is an advantage that the use efficiency of the consumed power is also increased.

In the above description, the technical idea of the present invention has been described with the accompanying drawings, which illustrate exemplary embodiments of the present invention by way of example and do not limit the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

1 is a schematic diagram of a display implemented with PMOLED.

2 shows the scan time of PMOLED.

3 illustrates the amount of scan time and current that illustrates the concept of the present invention.

4 shows a modified unit connection time T ' _PWM corresponding to an increased row scan time.

5 shows a 4 by 4 pixel array.

6 illustrates a three-step PMOLED driving method according to the present invention.

7 is a block diagram of a PMOLED driving circuit according to the present invention.

8 is a signal flow diagram for a PMOLED driving method according to the present invention.

Claims (8)

The scale factor S / F is calculated using the maximum number of PWM clocks N ' _total for processing the current frame data, and the variable current amount I' of the variable current device is calculated using the scale factor S / F. _d ) and a PWM operation unit (710) for calculating a crystal unit connection time (T ' _PWM ) used to switch the variable current; And And a line driver 720 for processing the horizontal and vertical line information of the panel included in the frame data in response to the variable current amount I _'d and the modification unit connection time T ' _PWM . , The line driver 720 drives the first horizontal line (i row, i is an integer) and the second horizontal line (i + 1 row, i is an integer) of the panel. The sum of the variable current amounts I _'d generated by the first variable current I ' _j1 and the second variable current I' _j2 respectively driving the vertical line is the first horizontal line i. i is an integer) and a first driving step (Pall) for supplying to the second horizontal line (i + 1 row, i is an integer), A second driving step of supplying the variable current amount I _'d generated by the second variable current device I ' _j2 for driving the vertical line to the first horizontal line (row i, i is an integer) P _o ) and A third drive for supplying the variable current amount I _'d generated by the second variable current device I ' _j2 driving the vertical line to the second horizontal line (i + 1 row, i is an integer) PMOLED driving circuit comprising the step (P _e ). The method of claim 1, wherein the PWM operation unit 710, The ratio of the maximum number of PWM clocks (N _total ) of one screen and the maximum number of PWM clocks (N ' _total ) for processing the frame data (

A scale factor calculator 711 for calculating the scale factor S / F; The scale factor (

) And the product of the primary current (I _d), (I _d x

A current amount calculating device (712) for calculating the variable current amount (I _'d ) determined by; And The basic unit connection time (T _PWM ) is calculated using the scale factor (

Divided by) (T _PWM x

And a unit connection time calculating device (713) for calculating the modified unit connection time (T ' _PWM ), which is determined by?). The method of claim 1, wherein the line driver 720, A first variable current (I ' _j1 ), a second variable current (I' _j2 ), a first switch (SW _j1 ) and a second switch (SW _j2 ) for driving the vertical line, One terminal of the first variable current device I ' _j1 and one terminal of the second variable current device I' _j2 are connected to a power supply terminal to generate a current of a variable current amount I ' _d , respectively. The first switch SW _j1 connects the other terminal of the first variable current device I ' _j1 and the other terminal of the second variable current device I' _j2 , The second switch SW _j2 selects one of the other terminal and the ground voltage GND of the first switch SW _j1 and connects it to the P-type electrode of the PMOLED. The method of claim 3, The first switch SW _j1 is turned on in the first driving step Pall, and is turned off in both the second driving step _Po and the third driving step _Pe . Said second switch (SW _j2) is turned on in the first driving step (Pall), the second driving step (P _o) and the third driving stage (P _e), The length of the turn-on time PMOLED driving circuit, characterized in that determined using the crystal unit connection time (T ' _PWM ) and the frame data. A scale factor calculation step S810 of calculating a scale factor using a maximum number of PWM clocks N ' _total for processing current frame data; A variable current amount and crystal unit connection time calculation step (S820) for calculating a crystal unit connection time used to determine the variable current amount supplied by the variable current device and the time when the variable current amount is supplied to the PMOLED using the scale factor; And And a PMOLED driving step (S930) for driving the panel in units of two lines by using the variable current amount, the modification unit connection time, and the frame data. Each of the two panel lines drives a first horizontal line (i row, i is an integer) and a second horizontal line (i + 1 row, i is an integer) of the panel. The sum of the variable current amounts I _'d generated by the first variable current I ' _j1 and the second variable current I' _j2 respectively driving the vertical line is the first horizontal line i. i is an integer) and a first driving step (Pall) for supplying to the second horizontal line (i + 1 row, i is an integer), A second driving step of supplying the variable current amount I _'d generated by the second variable current device I ' _j2 for driving the vertical line to the first horizontal line (row i, i is an integer) P _o ) and A third drive for supplying the variable current amount I _'d generated by the second variable current device I ' _j2 driving the vertical line to the second horizontal line (i + 1 row, i is an integer) PMOLED driving method comprising the step (P _e ) is driven. The method of claim 5, wherein the scale factor calculation step 810, Calculating a maximum PWM clock number (N _'t) for processing the current frame data 811; And Calculating the scale factor S / F which is the ratio of the maximum number of PWM clocks N _{t on} one screen and the maximum number of PWM clocks N ' _t for processing the current frame data (812); The variable current amount and correction unit connection time calculation step (S820), Calculating (821) the variable current amount by multiplying the scale factor by a base current amount; And Calculating a corrected unit connection time by dividing a basic unit connection time by the scale factor; The maximum number of PWM clocks on one screen is the product of the number of horizontal lines of the panel and one horizontal line, and is the product of the maximum number of PWM clocks required to implement the pixel of maximum brightness. The maximum number of PWM clocks for processing the frame data is the sum of the maximum number of PWM clocks required to implement the brightest pixel of each horizontal line, PMOLED driving method. The method of claim 5, wherein the third step of the PMOLED driving step (S830), A first step (833) of supplying current to the two PMOLEDs corresponding to the lower brightness among the brightnesses assigned to the two PMOLEDs disposed above and below the vertical lines respectively corresponding to the two horizontal lines; A second step (834) of further supplying a current corresponding to a difference between the brightness assigned to one PMOLED of the two PMOLEDs arranged up and down and the brightness selected in the first step, to the one PMOLED; And And a third step 835 of supplying a current corresponding to the difference between the brightness allocated to the other PMOLED among the two PMOLEDs arranged up and down and the brightness selected in the first step to the other PMOLED. PMOLED driving method, characterized in that. The method of claim 7, wherein In the first step 833, the current is supplied to the corresponding PMOLED from at least two current sources, and in the remaining two steps 834 and 835, the current is supplied from the one current source to the corresponding PMOLED. .

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