Display driving circuit

Abstract

The invention provides a display driving circuit, and in the display driving circuit, a first operational amplifier is provided with a first input end, a second input end and a first output end. The first input terminal is coupled to the first input switch and the second input terminal is coupled to a first output terminal outputting a first output signal. The second operational amplifier is provided with a third input end, a fourth input end and a second output end. The third input terminal is coupled to the second input switch and the fourth input terminal is coupled to a second output terminal outputting a second output signal. The first output circuit is coupled to the first output end of the first operational amplifier and is used for selectively outputting a first output signal to the display panel through the first channel or the second channel. The second output circuit is coupled to the second output end of the second operational amplifier and is used for selectively outputting a second output signal to the display panel through the first channel or the second channel.

Description

Technical Field

[0001] The present invention relates to a display, and in particular to a display driving circuit. Background Art

[0002] like Figure 1 As shown, in order for the display panel PL with a touch function to receive a good touch signal, the display driving circuit 1 needs to output a common driving signal VCOM to the display panel PL through a switch, and make the display panel PL generate the same common driving signal VCOM.

[0003] However, if the co-drive signal VCOM only drives the resistor-capacitor (RC) load of the data line of the entire display panel PL through the switch located after the first operational amplifier OA1 and the second operational amplifier OA2, its driving capability is obviously insufficient to cause the co-drive signal VCOM to be distorted, resulting in some distortion when the display panel PL receives the touch signal, which needs further improvement. Summary of the invention

[0004] Therefore, the present invention proposes a display driving circuit to effectively solve the above problems encountered in the prior art.

[0005] A preferred specific embodiment according to the present invention is a display driving circuit. In this embodiment, the display driving circuit is coupled to a display panel. The display driving circuit includes a first input switch, a first operational amplifier, a second input switch, a second operational amplifier, a first output circuit and a second output circuit. The first input switch is coupled to a common drive signal. The first operational amplifier corresponds to a first channel and has a first input terminal, a second input terminal and a first output terminal. The first input terminal is coupled to the first input switch and the second input terminal is coupled to the first output terminal. The first output terminal outputs a first output signal. The second input switch is coupled to a common drive signal. The second operational amplifier corresponds to a second channel and has a third input terminal, a fourth input terminal and a second output terminal. The third input terminal is coupled to the second input switch and the fourth input terminal is coupled to the second output terminal. The second output terminal outputs a second output signal. The first output circuit is coupled to the first output terminal of the first operational amplifier, and is used to selectively output the first output signal to the display panel through the first channel or the second channel. The second output circuit is coupled to the second output terminal of the second operational amplifier, and is used to selectively output the second output signal to the display panel through the first channel or the second channel.

[0006] In one embodiment, the display driving circuit further includes a buffer having a fifth input terminal, a sixth input terminal and a third output terminal. The fifth input terminal is coupled to the same drive signal and the sixth input terminal is coupled to the third output terminal. The third output terminal is coupled to and outputs the same drive signal to one end of the first input switch and the second input switch.

[0007] In one embodiment, when the co-driving signal is positive, the first input switch is turned on and the second input switch is turned off, so that the first input terminal of the first operational amplifier receives the co-driving signal.

[0008] In one embodiment, when the co-driving signal is of negative polarity, the second input switch is turned on and the first input switch is turned off, so that the third input terminal of the second operational amplifier receives the co-driving signal.

[0009] In one embodiment, the first output circuit includes a first output switch, a second output switch, a third output switch and a fourth output switch, the first output switch and the second output switch are connected in series between the first output terminal and the first channel of the first operational amplifier, and the third output switch and the fourth output switch are connected in series between the first output terminal and the second channel of the first operational amplifier.

[0010] In one embodiment, when the first output switch and the second output switch are turned on, the first output signal outputted by the first output terminal of the first operational amplifier is transmitted to the display panel through the first channel.

[0011] In one embodiment, when the third output switch and the fourth output switch are turned on, the first output signal outputted by the first output terminal of the first operational amplifier is transmitted to the display panel through the second channel.

[0012] In one embodiment, the second output circuit includes a fifth output switch, a sixth output switch, a seventh output switch and an eighth output switch, the fifth output switch and the sixth output switch are connected in series between the second output terminal of the second operational amplifier and the first channel, and the seventh output switch and the eighth output switch are connected in series between the second output terminal of the second operational amplifier and the second channel.

[0013] In one embodiment, when the fifth output switch and the sixth output switch are turned on, the second output signal outputted by the second output terminal of the second operational amplifier is transmitted to the display panel through the first channel.

[0014] In one embodiment, when the seventh output switch and the eighth output switch are turned on, the second output signal outputted by the second output terminal of the second operational amplifier is transmitted to the display panel through the second channel.

[0015] In one embodiment, the co-driving signal is an alternating current common voltage.

[0016] Compared with the prior art, when the display driving circuit of the present invention operates in the touch time, the co-driving signal provided by the internal circuit of the source driver IC is output from the output end of the buffer through the switch to the operational amplifier of the channel, and then output to the display panel through the operational amplifier of the channel. Since the operational amplifier of the channel alone drives the multiple data lines on the display panel, its driving capability is sufficient, so the co-driving signal will not be distorted and the display panel will not be distorted when receiving the touch signal, effectively overcoming the problems encountered by the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a traditional display driving circuit.

[0018] Figure 2 FIG. 4 is a schematic diagram of a display driving circuit in a preferred embodiment of the present invention.

[0019] Figure 3 The timing diagram shows that the scanning time of the display driving circuit is divided into display time and touch time.

[0020] Figure 4 The diagram is a schematic diagram of a first operational amplifier outputting a first output signal to a first output circuit when a first input switch is turned on and a second input switch is turned off.

[0021] Figure 5A and Figure 5B They are schematic diagrams of the first output circuit outputting the first output signal to the display panel through the first channel or the second channel.

[0022] Figure 6 The diagram is a schematic diagram of the second operational amplifier outputting the second output signal to the second output circuit when the first input switch is turned off and the second input switch is turned on.

[0023] Fig. 7A and Figure 7B Schematic diagrams of the second output circuit outputting the second output signal to the display panel through the first channel or the second channel respectively.

[0024] Figure 8 This is the timing diagram of the same drive signal.

[0025] Fig. 9 They are Figure 1 The same drive signal output to the panel is Figure 2 Timing diagram of the same-drive signal output to the panel compared to the same-drive signal at the source.

[0026] Description of main component symbols:

[0027] 1…Display driver circuit

[0028] 2…Display driver circuit

[0029] 20…First output circuit

[0030] 22...Second output circuit

[0031] V1…first voltage

[0032] V2…Second voltage

[0033] N1…first node

[0034] N2…Second node

[0035] BF…Buffer

[0036] OP1…First operational amplifier

[0037] OP2…Second operational amplifier

[0038] E1…First output

[0039] E2…Second output

[0040] E3…The third output

[0041] PL…Display Panel

[0042] SWA…First input switch

[0043] SWB…Second input switch

[0044] SW1…First output switch

[0045] SW2…Second output switch

[0046] SW3…The third output switch

[0047] SW4…Fourth output switch

[0048] SW5…Fifth output switch

[0049] SW6…Sixth output switch

[0050] SW7…The seventh output switch

[0051] SW8…8th output switch

[0052] CH1… Channel 1

[0053] CH2…Second channel

[0054] VA…First output signal

[0055] VB...Second output signal

[0056] VCOM…same drive signal

[0057] VC1...same drive signal

[0058] VC2...same drive signal

[0059] t1~t3…first time~third time

[0060] TS…Scan time

[0061] TD…Show time

[0062] TT…Touch Time DETAILED DESCRIPTION

[0063] A preferred embodiment of the present invention is a display driving circuit. In this embodiment, the display driving circuit is coupled to a display panel to drive the display panel to display an image. The display driving circuit can be a general display driving chip or a touch and drive integrated chip (TDDI), but is not limited thereto. There is no specific limitation on the type of display panel, which can be a liquid crystal display panel or a light emitting diode display panel, but is not limited thereto.

[0064] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the display driving circuit 2 in this embodiment. Figure 2 As shown, the display driving circuit 2 includes a buffer BF, a first input switch SWA, a second input switch SWB, a first operational amplifier OP1, a second operational amplifier OP2, a first output circuit 20 and a second output circuit 22.

[0065] The buffer BF has a fifth input terminal +, a sixth input terminal - and a third output terminal E3. The fifth input terminal + is coupled to the common drive signal VCOM and the sixth input terminal - is coupled to the third output terminal E3. The third output terminal E3 is coupled to and outputs the common drive signal VCOM to one end of the first input switch SWA and the second input switch SWB. In practical applications, the common drive signal VCOM can be an alternating current common voltage (AC VCOM) provided by the internal circuit of the source driver IC, but is not limited thereto.

[0066] The first operational amplifier OP1 has a first input terminal +, a second input terminal - and a first output terminal E1. The first input terminal + is coupled to the first input switch SWA and the second input terminal - is coupled to the first output terminal E1. The first output terminal E1 outputs a first output signal VA. The first input switch SWA is coupled to the same drive signal VCOM.

[0067] The second operational amplifier OP2 has a third input terminal +, a fourth input terminal - and a second output terminal E2. The third input terminal + is coupled to the second input switch SWB and the fourth input terminal - is coupled to the second output terminal E2. The second output terminal E2 outputs a second output signal VB. The second input switch SWB is coupled to the same drive signal VCOM.

[0068] The first output circuit 20 is coupled to the first output terminal E1 of the first operational amplifier OP1, and is used to selectively output the first output signal VA to the display panel PL through the first channel CH1 or the second channel CH2. In this embodiment, the first output circuit 20 includes a first output switch SW1, a second output switch SW2, a third output switch SW3, and a fourth output switch SW4. The first output switch SW1 and the second output switch SW2 are connected in series between the first output terminal E1 of the first operational amplifier OP1 and the first channel CH1, and the third output switch SW3 and the fourth output switch SW4 are connected in series between the first output terminal E1 of the first operational amplifier OP1 and the second channel CH2.

[0069] The second output circuit 22 is coupled to the second output terminal E2 of the second operational amplifier OP2, and is used to selectively output the second output signal VB to the display panel PL through the first channel CH1 or the second channel CH2. In this embodiment, the second output circuit 22 includes a fifth output switch SW5, a sixth output switch SW6, a seventh output switch SW7, and an eighth output switch SW8. The fifth output switch SW5 and the sixth output switch SW6 are connected in series between the second output terminal E2 of the second operational amplifier OP2 and the first channel CH1, and the seventh output switch SW7 and the eighth output switch SW8 are connected in series between the second output terminal E2 of the second operational amplifier OP2 and the second channel CH2.

[0070] Please refer to Figure 3 , Figure 3 The timing diagram shows that the scanning time of the display driving circuit is divided into display time and touch time. Figure 3 As shown, the scanning time TS of the display driving circuit 2 is from the first time t1 to the third time t3, wherein the first time t1 to the second time t2 is the display time TD for driving the display panel PL to display the picture, and the second time t2 to the third time t3 is the touch time TT for touch sensing of the display panel PL, but not limited to this.

[0071] In this embodiment, the co-driving signal VCOM is provided within the touch time TT. The co-driving signal VCOM is an AC common voltage and can be a positive polarity or a negative polarity signal without any specific limitation.

[0072] Please refer to Figure 4 , Figure 4 The diagram is a schematic diagram of a first operational amplifier outputting a first output signal to a first output circuit when a first input switch is turned on and a second input switch is turned off.

[0073] like Figure 4As shown, when the co-driving signal VCOM is positive, the first input switch SWA is turned on and the second input switch SWB is turned off, so that the first input terminal + of the first operational amplifier OP1 receives the co-driving signal VCOM and the output terminal E1 of the first operational amplifier OP1 outputs the first output signal VA to the first output circuit 20.

[0074] Please refer to Figure 5A and Figure 5B , Figure 5A and Figure 5B They are schematic diagrams of the first output circuit outputting the first output signal to the display panel through the first channel or the second channel.

[0075] like Figure 5A As shown, when the first output switch SW1 and the second output switch SW2 connected in series in the first output circuit 20 are turned on and the third output switch SW3 and the fourth output switch SW4 connected in series are turned off, the first output signal VA outputted by the first output terminal E1 of the first operational amplifier OP1 is transmitted to the display panel PL through the first channel CH1.

[0076] like Figure 5B As shown, when the third output switch SW3 and the fourth output switch SW4 connected in series in the first output circuit 20 are turned on and the first output switch SW1 and the second output switch SW2 connected in series are turned off, the first output signal VA outputted by the first output terminal E1 of the first operational amplifier OP1 is transmitted to the display panel PL through the second channel CH2.

[0077] Please refer to Figure 6 , Figure 6 The diagram is a schematic diagram of the second operational amplifier outputting the second output signal to the second output circuit when the first input switch is turned off and the second input switch is turned on.

[0078] like Figure 6 As shown, when the co-driving signal VCOM is negative, the second input switch SWB is turned on and the first input switch SWA is turned off, so that the third input terminal + of the second operational amplifier OP2 receives the co-driving signal VCOM and the output terminal E2 of the second operational amplifier OP2 outputs the second output signal VB to the second output circuit 22.

[0079] Please refer to Fig. 7A and Figure 7B , Fig. 7A and Figure 7B Schematic diagrams of the second output circuit outputting the second output signal to the display panel through the first channel or the second channel respectively.

[0080] like Fig. 7AAs shown, when the fifth output switch SW5 and the sixth output switch SW6 connected in series in the second output circuit 22 are turned on, the second output signal VB outputted by the second output terminal E2 of the second operational amplifier OP2 is transmitted to the display panel PL through the first channel CH1.

[0081] like Figure 7B As shown, when the seventh output switch SW7 and the eighth output switch SW8 connected in series in the second output circuit 22 are turned on, the second output signal VB outputted by the second output terminal E2 of the second operational amplifier OP2 is transmitted to the display panel PL through the second channel CH2.

[0082] Please also refer to Figure 8 , Figure 8 is the timing diagram of the same drive signal. Figure 8 As shown, before the first time t1, the co-drive signal VCOM maintains a low level; at the first time t1, the co-drive signal VCOM changes from a low level to a high level; during the first time t1 to the second time t2, the co-drive signal VCOM maintains a high level; at the second time t2, the co-drive signal VCOM changes from a high level to a low level.

[0083] Please also refer to Fig. 9 , Fig. 9 They are Figure 1 The same drive signal output to the panel is Figure 2 The same drive signal output to the panel is compared with Figure 8 The source of the same drive signal timing diagram.

[0084] like Fig. 9 As shown, assuming Figure 1 The same drive signal output to the panel PL is VC1 and Figure 2 The same driving signal output to the panel PL is VC2. At the first time t1, Figure 2 The speed at which the same drive signal VC2 output to the panel PL changes from a low level to a high level is faster than that of the prior art. Figure 1 The speed at which the same driving signal VC1 output to the panel PL changes from a low level to a high level is faster, that is, Figure 2 The same drive signal VC2 output to the panel PL will be higher than that of the prior art. Figure 1 The same drive signal VC1 output to the panel PL is closer to Figure 8 The source of the same drive signal VCOM.

[0085] Similarly, at the second time t2, Figure 2 The speed ratio of the same drive signal VC2 output to the panel PL from high level to low level is Figure 1 The speed at which the same drive signal VC1 output to the panel PL changes from a high level to a low level is faster, that is, Figure 2The same drive signal VC2 output to the panel PL will be Figure 1 The same drive signal VC1 output to the panel PL is closer to Figure 8 The source of the same drive signal VCOM.

[0086] Compared with the prior art, when the display driving circuit of the present invention operates in the touch time, the co-driving signal provided by the internal circuit of the source driver IC is output from the output end of the buffer through the switch to the operational amplifier of the channel, and then output to the display panel through the operational amplifier of the channel. Since the operational amplifier of the channel alone drives the multiple data lines on the display panel, its driving capability is sufficient, so the co-driving signal will not be distorted and the display panel will not be distorted when receiving the touch signal, effectively overcoming the problems encountered by the prior art.

Claims

1. A display driving circuit coupled to a display panel, characterized in that: The display driving circuit comprises: A first input switch coupled to a common drive signal; A first operational amplifier having a first input terminal, a second input terminal and a first output terminal, wherein the first input terminal is coupled to the first input switch and the second input terminal is coupled to the first output terminal, and the first output terminal outputs a first output signal; A second input switch coupled to the same drive signal; A second operational amplifier having a third input terminal, a fourth input terminal and a second output terminal, wherein the third input terminal is coupled to the second input switch and the fourth input terminal is coupled to the second output terminal, and the second output terminal outputs a second output signal; A first output circuit, coupled to the first output terminal of the first operational amplifier, for selectively outputting the first output signal to the display panel through the first channel or the second channel; and The second output circuit is coupled to the second output terminal of the second operational amplifier and is used for selectively outputting the second output signal to the display panel through the first channel or the second channel.

2. The display driving circuit according to claim 1, characterized in that: Also includes: The buffer has a fifth input terminal, a sixth input terminal and a third output terminal, wherein the fifth input terminal is coupled to the same drive signal and the sixth input terminal is coupled to the third output terminal, and the third output terminal is coupled to and outputs the same drive signal to one end of the first input switch and the second input switch.

3. The display driving circuit according to claim 2, characterized in that: When the co-driving signal is positive, the first input switch is turned on and the second input switch is turned off, so that the first input terminal of the first operational amplifier receives the co-driving signal.

4. The display driving circuit according to claim 2, wherein: When the co-driving signal is of negative polarity, the second input switch is turned on and the first input switch is turned off, so that the third input terminal of the second operational amplifier receives the co-driving signal.

5. The display driving circuit according to claim 1, wherein: The first output circuit includes a first output switch, a second output switch, a third output switch and a fourth output switch. The first output switch and the second output switch are connected in series between the first output end of the first operational amplifier and the first channel, and the third output switch and the fourth output switch are connected in series between the first output end of the first operational amplifier and the second channel.

6. The display driving circuit according to claim 5, characterized in that: When the first output switch and the second output switch are turned on, the first output signal outputted by the first output terminal of the first operational amplifier is transmitted to the display panel through the first channel.

7. The display driving circuit according to claim 5, characterized in that: When the third output switch and the fourth output switch are turned on, the first output signal outputted by the first output terminal of the first operational amplifier is transmitted to the display panel through the second channel.

8. The display driving circuit according to claim 1, wherein: The second output circuit includes a fifth output switch, a sixth output switch, a seventh output switch and an eighth output switch, the fifth output switch and the sixth output switch are connected in series between the second output end of the second operational amplifier and the first channel, and the seventh output switch and the eighth output switch are connected in series between the second output end of the second operational amplifier and the second channel.

9. The display driving circuit according to claim 8, characterized in that: When the fifth output switch and the sixth output switch are turned on, the second output signal outputted by the second output terminal of the second operational amplifier is transmitted to the display panel through the first channel.

10. The display driving circuit according to claim 8, characterized in that: When the seventh output switch and the eighth output switch are turned on, the second output signal outputted by the second output terminal of the second operational amplifier is transmitted to the display panel through the second channel.

11. The display driving circuit according to claim 1, characterized in that: The co-driving signal is an AC common voltage.

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