TWI543139B - Driving device for display panel - Google Patents

Description

Display panel drive

The present invention relates to a driving device, and more particularly to a driving device for a display panel.

FIG. 1 is a schematic diagram of a conventional driving device suitable for a Light Emitting Diode (LED) display panel. As shown in FIG. 1, the conventional driving device 100 includes a switching circuit 110 and a driving circuit 120. When the existing driving device 100 is to illuminate the light-emitting diode D2 in the LED display panel 101, the switching circuit 110 turns on the scan line SL2 to the ground voltage, and causes the scan lines SL1, SL3 and SL4 to float. Further, the driving circuit 120 supplies a driving current to the driving line DL1 to thereby drive the light emitting diode D2.

However, when the light-emitting diode D2 to be lit is opened, the voltage on the driving line DL1 is pulled up to a high level (for example, a power supply voltage) in response to the open circuit of the light-emitting diode D2, thereby causing The light-emitting diodes D1, D3 and D4, which are not required to be lit, appear to be briefly turned on, resulting in a slight abnormality of the light-emitting diodes D1, D3 and D4. In other words, under the driving of the existing driving device 100, the LED display panel 101 tends to be different according to the opening of the internal light-emitting diode. The situation is often bright, which in turn leads to a decrease in display quality.

The invention provides a driving device for determining whether to supply a driving current to a driving line according to state information of a light emitting diode. Thereby, it is possible to prevent the display panel from being abnormally brightened in response to the opening of the light-emitting diode, thereby improving the display quality of the display panel.

The driving device of the present invention is used to drive a display panel. The display panel includes a plurality of driving lines, a plurality of scanning lines, and a plurality of light emitting diodes, wherein the plurality of light emitting diodes are disposed at an intersection of the plurality of driving lines and the plurality of scanning lines. The plurality of scan lines are electrically connected to the plurality of scan switches, and the driving device comprises a plurality of driving circuits and a plurality of detecting circuits. The plurality of driving circuits are electrically connected to the plurality of driving lines, and provide a plurality of driving currents to the plurality of driving lines during a previous driving to drive the plurality of light emitting diodes. The plurality of detection circuits are electrically connected to the plurality of driving lines, and detect voltages on the plurality of driving lines during a previous driving period to generate a plurality of open circuit determination signals. The scan order discrimination signal corresponds to an on period of the plurality of scan switches. During the previous driving, the driving device stores the plurality of status information of the plurality of light emitting diodes according to the plurality of open circuit determining signals and the scanning order determining signal. During the current driving period, the driving device determines whether to provide the plurality of driving currents to the plurality of driving lines through the plurality of driving circuits according to the plurality of state information.

Based on the above, the driving device of the present invention can be based on the voltage on the driving line and The scanning sequence discriminates the signal to store the status information of the LED, and can determine whether to supply the driving current to the driving line connected to the LED according to the status information. Thereby, it is possible to prevent the display panel from being abnormally brightened in response to the opening of the light-emitting diode, thereby effectively improving the display quality of the display panel.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧ Existing drive unit

101‧‧‧LED display panel

110, 202‧‧‧ switch circuit

120, 211~214, 311~314‧‧‧ drive circuit

201‧‧‧ display panel

200, 300‧‧‧ drive

221~224‧‧‧Detection circuit

240, 340‧‧‧ control circuit

D1~D4, D11~D14, D21~D24, D31~D34‧‧‧Lighting diode

DL1, DL21~DL24‧‧‧ drive line

SL1~SL4, SL21~SL24‧‧‧ scan lines

21~24‧‧‧ scan switch

235~238, 341~344, 351~354‧‧‧ switch

SC21~SC24‧‧‧Switch signal

231~234, 331~334‧‧‧current source

EN21~EN24, EN31~EN34‧‧‧ control signals

DT2‧‧‧ scan order discrimination signal

VS‧‧‧Power supply voltage

S21~S24‧‧‧Open circuit judgment signal

AD31~AD34‧‧‧ adjustment signal

V3‧‧‧Adjust voltage

FIG. 1 is a schematic view of a conventional driving device suitable for a light emitting diode display panel.

2 is a schematic diagram of a driving device in accordance with an embodiment of the present invention.

3 is a schematic view of a driving device in accordance with another embodiment of the present invention.

2 is a schematic diagram of a driving device in accordance with an embodiment of the present invention. As shown in FIG. 2, the driving device 200 is used to drive a display panel 201. The display panel 201 can be, for example, a light emitting diode display panel. For example, the display panel 201 includes a plurality of driving lines DL21 to DL24, a plurality of scanning lines SL21 to SL24, and LEDs D11 to D14, D21 to D24, D31 to D34, and D41 to D44. The driving lines DL21 to DL24 are disposed to intersect with the scanning lines SL21 to SL24, and each of the light emitting diodes is disposed at an intersection of a driving line and a scanning line. For example, LED diode D11 settings At the intersection of the drive line DL21 and the scan line SL21. And so on, the settings of the LEDs D12~D14, D21~D24, D31~D34 and D41~D44.

In addition, the scan lines SL21 to SL24 in the display panel 201 are electrically connected to a switch circuit 202. The switch circuit 202 can turn on the scan lines SL21~SL24 one by one to the reference voltage. For example, the switch circuit 202 includes scan switches 21-24. Among them, the scan switches 21 to 24 are in one-to-one correspondence with the scan lines SL21 to SL24. In addition, each of the scan switches 21-24 is electrically connected between the corresponding scan line and the reference voltage. For example, the scan switch 21 is electrically connected between the scan line SL21 and a reference voltage (eg, a ground voltage). In operation, the switch circuit 202 can control the scan switches 21-24 according to the switching signals SC21~SC24 to scan the scan lines SL21~SL24 in the display panel 201 one by one. For example, the switch circuit 202 can turn on the scan switch 21 and turn off the remaining scan switches 22-24 to scan to the scan line SL21 in the display panel 201.

The driving device 200 includes a plurality of driving circuits 211 to 214 and a plurality of detecting circuits 221 to 224. The driving circuits 211 to 214 are in one-to-one correspondence with the driving lines DL21 to DL24, and each driving circuit is electrically connected to the corresponding driving line. For example, the drive circuit 211 includes a current source 231 and a switch 235. The first end of the current source 231 is electrically connected to the power supply voltage VS, and the switch 235 is electrically connected between the second end of the current source 231 and the driving line DL21. That is, the current source 231 is connected in series with the switch 235 between the power supply voltage VS and the drive line DL21. Similarly, the driving circuits 212-214 include current sources 232-234 and switches 236-238, and the connection architecture of the current sources 232-234 and the switches 236-238 is similar to the connection structure of the current source 231 and the switch 235.

In operation, current sources 231-234 can each generate a drive current. In addition, the driving circuits 211 to 214 can control the switches 235 to 238 according to the control signals EN21 to EN24 to determine whether to supply the driving current to the light emitting diodes on the scanned scanning line. For example, when the switch circuit 202 scans the scan line SL21 in the display panel 201, the drive circuits 211-214 may turn on some or all of the switches 235-238 to provide drive current to some or all of the drive lines DL21~DL24. . Thereby, the driving device 200 electrically connects some or all of the light-emitting diodes D11, D21, D31, and D41 electrically connected to the scanning line SL21.

The detecting circuits 221 to 224 are in one-to-one correspondence with the driving lines DL21 to DL24, and each detecting circuit is electrically connected to the corresponding driving line. In addition, the detection circuits 221 to 224 can be used to generate the open circuit determination signals S21 to S24. Specifically, during a driving period (for example, a previous driving period), the driving circuits 211 to 214 turn on the switches 235 to 238 so that the driving currents generated by the current sources 231 to 234 are supplied to the driving lines DL21 to DL24. In addition, during the previous driving period, the detecting circuits 221 to 224 detect the voltages of the driving lines DL21 to DL24, and generate open circuit determining signals S21 to S24 according to the detected voltage.

Further, the drive device 200 receives the scan order discrimination signal DT2. The scan order discrimination signal DT2 corresponds to the on period of the scan switches 21 to 24, and the scan order discrimination signal DT2 can be, for example, a clock signal. In other words, the drive device 200 can determine the period during which the scan switches 21 to 24 are turned on according to the scan order discrimination signal DT2 (that is, the scan order of the scan lines SL21 to SL24). For example, the driving device 200 can accumulate a count value according to the clock signal. In addition, when the count value is added to a fixed value At this time, it means that the switch circuit 202 will scan the next scan line. In other words, each time the count value is accumulated to a fixed value, the driving device 200 can know that the switch circuit 202 will switch to the next scan line, thereby discriminating which scan line the switch circuit 202 scans. Therefore, during the previous driving period, the driving device 200 can determine whether the LED in the display panel 201 has an open circuit according to the open circuit determination signals S21 S S24 and the scanning order discrimination signal DT2, and can determine according to the discrimination. As a result, the state information of the light-emitting diodes in the display panel 201 is stored. In addition, during the next driving period (for example, the current driving period), the driving device 200 can determine whether to provide driving current to the driving lines DL21 to DL24 through the driving circuits 211 to 214 according to the state information of the LEDs.

Taking the light-emitting diode D22 in the display panel 201 as an example, during a driving period (for example, during a previous driving period), the driving device 200 can discriminate the scanning connected to the LED D22 according to the scanning order discrimination signal DT2. Whether the line SL22 is scanned. Thereby, when the scan line SL22 is scanned, the driving device 200 can store the state information of the light-emitting diode D22 according to the open circuit determination signal S22. Moreover, during the next driving period (for example, the current driving period), the driving device 200 determines whether to provide the driving current to the driving line DL22 through the driving circuit 212 according to the stored state information of the LEDs 22 .

It is worth mentioning that in an embodiment, the driving device 200 further includes a control circuit 240. The control circuit 240 can generate control signals EN21~EN24 for controlling the driving circuits 211~214. In addition, during a driving period (eg, during a previous driving period), the control circuit 240 can be turned on by the control signals EN21~EN24. The switches 235 to 238 are such that the drive currents generated by the current sources 231 to 234 are supplied to the drive lines DL21 to DL24. Furthermore, the control circuit 240 can store the state information of the light-emitting diodes in the display panel 201 according to the open circuit determination signals S21 S S24 and the scan order discrimination signal DT2. In addition, during the next driving period (for example, the current driving period), the control circuit 240 may determine whether to provide the driving current to the driving lines DL21 to DL24 through the driving circuits 211 to 214 according to the stored state information of the LEDs.

Specifically, taking the light-emitting diode D22 in the display panel 201 as an example, during a driving period (for example, during a previous driving period), the control circuit 240 can discriminate the light-emitting diode D22 according to the scanning order discrimination signal DT2. Whether the connected scan line SL22 is scanned. Thereby, when the scan line SL22 is scanned, the control circuit 240 can store the state information of the light-emitting diode D22 according to the open circuit determination signal S22.

For example, the light-emitting diode D22 has an open circuit. Therefore, during the previous driving period, as the switch 236 is turned on, the voltage on the driving line DL22 is pulled up to the power supply voltage VS in response to the open circuit of the light emitting diode D22. It is worth mentioning that if the LED diode 22 does not open, the voltage on the driving line DL22 will be equal to the forward voltage (VF) of the LED, and the voltage will be less than the power voltage VS. . Therefore, the detecting circuit 222 can compare the voltage on the driving line DL22 with a reference voltage, for example, the reference voltage is slightly larger than the turn-on voltage of the light-emitting diode or slightly smaller than the power supply voltage VS. When the voltage on the driving line DL22 is greater than the reference voltage, the detecting circuit 222 can determine the light emitting The pole body D22 has an open circuit condition and generates an open circuit determination signal S22 having a first level. In addition, in another embodiment, when the voltage on the driving line DL22 is not greater than the reference voltage, the detecting circuit 222 can determine that the light-emitting diode D22 does not have an open circuit, and generate an open circuit judgment with the second level. Signal S22.

In other words, during the previous driving period, the control circuit 240 can determine that the light-emitting diode D22 is an open circuit according to the open circuit determination signal S22 having the first level and the scanning order discrimination signal DT2, and store the light-emitting diode according to the storage. D22 is the status information of the open circuit. Thereby, during the current driving period, the state information of the stored LEDs 22 can display the LEDs 22 as an open circuit. At this time, the control circuit 240 will not pass the switch 236 through the control signal EN22, so that the drive circuit 212 does not supply the drive current to the drive line DL22. Since the drive circuit 212 does not supply the drive current to the drive line DL22, the voltage on the drive line DL22 will not be pulled up to the supply voltage VS. Thereby, the voltages at the anodes of the light-emitting diodes D21, D23, and D24 can be relatively lowered, thereby reducing the abnormal conduction of the light-emitting diodes D21, D23, and D24. In this way, the display panel 201 can be prevented from being abnormally brightened in response to the opening of the light-emitting diode D22, and the display quality of the display panel 201 can be effectively improved.

Further, taking the light-emitting diode D12 in the display panel 201 as an example, the light-emitting diode D12 does not have an open circuit. Therefore, the driving circuit 211 can supply the driving current to the driving line DL21 during a previous driving period, so that the detecting circuit 221 determines that the light-emitting diode D12 does not open according to the voltage on the driving line DL22 and the scanning order discrimination signal DT2. Causing the control circuit 240 to store the light emitting diode Body D12 is a normal status message. On the other hand, during the current driving period, the status information of the stored light-emitting diode D12 will show that the light-emitting diode D12 is not open. At this time, the control circuit 240 turns on the switch 235 through the control signal EN21 to cause the drive circuit 211 to supply the drive current to the drive line DL21.

Although the embodiment of FIG. 2 exemplifies the implementation of the driver circuit, it is not intended to limit the invention. For example, FIG. 3 is a schematic diagram of a driving apparatus according to another embodiment of the present invention. Among them, the driving device 300 listed in FIG. 3 is similar to the driving device 200 listed in FIG. 2 .

The main difference between the embodiment of FIG. 3 and FIG. 2 is that the control circuit 340 in the driving device 300 of FIG. 3 controls the driving circuits 311 to 314 by using the control signals EN31~EN34 and the adjustment signals AD31~AD34, and the driving circuit 311~ 314 includes current sources 331-334, switches 341-344, and switches 351-354. Taking the driving circuit 311 as an example, the first end of the current source 331 is electrically connected to the power supply voltage VS. The switch 341 is electrically connected between the second end of the current source 331 and the driving line DL21, and the switch 341 is controlled by the control signal EN31. The switch 351 is electrically connected between the driving line DL21 and the adjustment voltage V3, and the switch 351 is controlled by the adjustment signal AD31. And so on, the connection structure of the current source 332~334, the switch 342~344 and the switch 352~354.

Taking the light-emitting diode D22 in the display panel 201 as an example, during a driving period (for example, during a previous driving period), the control circuit 340 turns on the switch 342 by using the control signal EN32, and does not turn on the switch 352 by using the adjusting signal AD32. . Thereby, the drive circuit 312 will provide a drive current to the drive line DL22. Moreover, the detecting circuit 222 detects the voltage on the driving line DL22 and generates according to the voltage. Open circuit determination signal S22. Thereby, the control circuit 340 can store the state information of the light-emitting diode D22 according to the open circuit determination signal S22 and the scanning order discrimination signal DT2. In the embodiment of FIG. 3, since the light-emitting diode D22 has an open circuit, the detecting circuit 222 generates an open circuit determining signal S22 having a first level, thereby causing the control circuit 340 to store the light-emitting diode D22 as an open circuit. Status information.

Furthermore, during the next driving period (eg, during the current driving period), the status information of the stored LEDs 22 will show that the LEDs 22 are open. At this time, the control circuit 340 turns on the switch 342 and the switch 352 by using the control signal EN32 and the adjustment signal AD32, so that the driving circuit 312 does not supply the driving current to the driving line DL22. Further, as the switch 342 and the switch 352 are turned on, the voltage on the drive line DL22 will be adjusted to the adjustment voltage V3. The adjustment voltage V3 is smaller than the cut-in voltage of the light-emitting diode. In other words, as the switch 342 and the switch 352 are turned on, the voltage on the drive line DL22 will not be pulled up to the power supply voltage VS. Thereby, the voltages at the anodes of the light-emitting diodes D21, D23, and D24 can be relatively lowered, thereby reducing the abnormal conduction of the light-emitting diodes D21, D23, and D24. In this way, the display panel 201 can be prevented from being abnormally brightened in response to the opening of the light-emitting diode D22, and the display quality of the display panel 201 can be effectively improved.

It should be noted that in another embodiment, the driving circuit 312 can also stop supplying the driving current and adjust the voltage on the driving line DL22 to the adjustment voltage V3 by the non-conduction of the switch 342 and the conduction of the switch 352. That is, in another embodiment, when the status information of the stored light-emitting diode D22 is displayed during the current driving period When the light-emitting diode D22 is open circuit, the control circuit 340 can turn on the switch 342 by using the control signal EN32, and turn on the switch 352 by using the adjustment signal AD32. Thereby, the driving circuit 312 will not supply the driving current to the driving line DL22, and the voltage on the driving line DL22 will be adjusted to the adjustment voltage V3, so that the display panel 201 can be prevented from being abnormally brightened in response to the opening of the light-emitting diode D22. Case.

Further, taking the light-emitting diode D12 in the display panel 201 as an example, the light-emitting diode D12 does not have an open circuit. Therefore, the driving circuit 311 can supply the driving current to the driving line DL21 during a previous driving period, so that the detecting circuit 221 determines that the light-emitting diode D12 does not open according to the voltage on the driving line DL21 and the scanning order discrimination signal DT2. The control circuit 240 is caused to store the state information of the light-emitting diode D12 as normal. On the other hand, during the current driving period, the status information of the stored light-emitting diode D12 will show that the light-emitting diode D12 is not open. At this time, the control circuit 340 turns on the switch 341 to not turn on the switch 351, so that the drive circuit 311 supplies the drive current to the drive line DL21. The detailed description of the embodiment of Fig. 3 is included in the above embodiment, and therefore will not be described herein.

In summary, the driving device of the present invention can generate an open circuit determining signal according to the voltage on the driving line, and can determine whether the light emitting diode in the display panel has an open circuit according to the open circuit determining signal, thereby storing the light emitting diode. Status information. In addition, the driving device can determine whether to provide a driving current to the driving line through the driving circuit according to the state information of the LED. Thereby, it is possible to prevent the display panel from being abnormally brightened in response to the opening of the light-emitting diode, thereby effectively improving the display quality of the display panel.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

200‧‧‧ drive

211~214‧‧‧ drive circuit

221~224‧‧‧Detection circuit

231~234‧‧‧current source

235~238‧‧‧Switch

240‧‧‧Control circuit

201‧‧‧ display panel

202‧‧‧Switch circuit

21~24‧‧‧ scan switch

D11~D14, D21~D24, D31~D34, D41~D44‧‧‧Lighting diode

DL21~DL24‧‧‧ drive line

SL21~SL24‧‧‧ scan line

DT2‧‧‧ scan order discrimination signal

VS‧‧‧Power supply voltage

S21~S24‧‧‧Open circuit judgment signal

SC21~SC24‧‧‧Switch signal

EN21~EN24‧‧‧Control signal

Claims (9)

a driving device for driving a display panel, the display panel includes a plurality of driving lines, a plurality of scanning lines and a plurality of light emitting diodes, wherein the light emitting diodes are disposed on the driving lines and the scanning lines In the interlaced manner, the scan lines are electrically connected to the plurality of scan switches, and the driving device comprises: a plurality of driving circuits electrically connected to the driving lines, and providing a plurality of driving currents to the driving during a previous driving a line for driving the light emitting diodes; a plurality of detecting circuits electrically connected to the driving lines, and detecting voltages on the driving lines during the previous driving to generate a plurality of open circuit determining signals; a scanning sequence discriminating signal corresponding to the opening period of the scan switches; during the previous driving, the driving device stores the plurality of state information of the light emitting diodes according to the open circuit determining signals and the scanning order discriminating signals, and During a current driving period, the driving device determines whether to provide the driving currents to the driving lines through the driving circuits according to the state information. The driving device of claim 1, wherein when a first state information of the state information is displayed during the current driving period, a first light emitting diode of the light emitting diodes is open a first driving circuit of the driving circuits does not provide a first driving current of the driving currents to a first driving line of the driving lines electrically connected to the first LEDs. The first state information provides the first driving circuit to the first driving line when the first driving diode is in an open state during the current driving period. The driving device of claim 2, wherein the first driving The circuit includes: a current source, the first end of which is electrically connected to a power supply voltage; and a switch electrically connected between the second end of the current source and the first driving line, wherein the first state information is When the current driving period indicates that the first LED is not open, the first driving circuit turns on the switch, and when the first state information shows that the first LED is an open circuit during the current driving, the The first drive circuit does not turn on the switch. The driving device of claim 2, wherein the first driving circuit comprises: a current source, the first end of which is electrically connected to a power supply voltage; and a first switch electrically connected to the current source Between the two ends and the first driving line; and a second switch electrically connected between the first driving line and an adjustment voltage, wherein the first state information is displayed during the current driving period When the LED is not open, the first driving circuit turns on the first switch and does not turn on the second switch. When the first state information indicates that the first LED is open during the current driving period, The first driving circuit turns on the first switch and the second switch. The driving device of claim 2, wherein the first driving circuit comprises: a current source, the first end of which is electrically connected to a power supply voltage; and a first switch electrically connected to the current source Between the two ends and the first drive line; a second switch electrically connected between the first driving line and an adjustment voltage, wherein when the first state information indicates that the first LED is not open during the current driving, the first The driving circuit turns on the first switch and does not turn on the second switch. When the first state information indicates that the first light emitting diode is open during the current driving, the first driving circuit does not turn on the first switch and The second switch is turned on. The driving device of claim 4 or 5, wherein the adjustment voltage is less than the all-in voltage of the light-emitting diodes. The driving device of claim 1, wherein the scanning order discrimination signal can be a clock signal. The driving device of claim 1, further comprising: a control circuit, during the previous driving, controlling the driving circuits to cause the driving circuits to supply the driving currents to the driving lines, and according to The open circuit determination signals and the scan order discrimination signals store the state information of the light emitting diodes, and during the current driving, determine, according to the state information, whether to provide the driving currents through the driving circuits to the Some drive lines. The driving device of claim 8, wherein when a first state information of the state information is displayed during the current driving period, a first light emitting diode of the light emitting diodes is open The control circuit controls a first one of the driving circuits, so that the first driving circuit does not provide a first driving current of the driving currents to the driving lines to electrically connect the first light a first driving line of the diode, when the first state information is displayed during the current driving When the first light emitting diode is not open, the control circuit controls the first driving circuit to cause the first driving circuit to supply the first driving current to the first driving line.