Touch display device, driving signal output circuit, and driving signal output method of touch display device

Abstract

This disclosure provides a touch display device and a method and circuit for outputting drive signals thereto. Specifically, it provides a touch display device, a drive signal output circuit, and a method for outputting drive signals of the touch display device to a panel, allowing selective output of display drive signals and touch drive signals with different voltage levels.

Description

Technical Field

[0001] This disclosure relates to a touch display device, a drive signal output circuit, and a method for outputting drive signals for the touch display device. Prior Technology

[0002] With the advancement of information technology, various display devices capable of visualizing information are being developed. Liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, and plasma display panels (PDPs) are examples of display devices that have been developed or have only recently been developed. Such display devices are under development to appropriately display high-resolution images.

[0003] Recently, many display panels included in various electronic devices (e.g., mobile devices) have incorporated touch functionality. In this case, the display panel can be implemented as a flat panel display device such as a liquid crystal display (LCD), and the touch functionality can be implemented as a touch panel combined with the display panel. A touch panel refers to a transparent switch panel that has the function of operating the device or executing a program in response to the user's pressing of text, images, or icons.

[0004] Touch panels can be configured to perform capacitive touch recognition, and as an example of a touch panel implementing capacitive touch recognition, US Patent Application Publication 2009 / 0091551 discloses a "mutual capacitive touch sensing device." General touch modes have a structure independent of the display panel and are manufactured separately and combined with the display panel. As described above, the configuration of combining the touch panel and the display panel leads to various difficulties such as increased process complexity and manufacturing costs.

[0005] To address this issue, the development of devices that can share components for display and components for touch recognition is being promoted, and a representative example of such devices is the in-cell approach. The in-cell approach means implementing touch recognition by configuring touch functionality within pixels of the display panel, and various methods are being developed for this purpose. Pixels implemented using the in-cell approach can simultaneously perform both display and touch recognition functions.

[0006] When touch operation and display operation are implemented in a time-division manner in a device that provides both touch and display functions (hereinafter referred to as "touch display device"), the display drive signal Display VCOM and the touch drive signal Touch VCOM can be switched to selectively supply to the panel (e.g., a touch display panel or a touch screen panel).

[0007] When the signal amplitudes of the display drive signal and the touch drive signal are not at the same voltage level, the circuitry used to selectively supply the display drive signal and the touch drive signal to the panel (e.g., source driver and touch readout IC (SRIC)) needs to include components capable of operating over a relatively wide voltage range (e.g., high voltage (HV)). This results in a relatively large footprint and high cost due to the inclusion of components capable of operating over a relatively wide voltage range in the configuration of the touch display device. Additionally, an external power supply and internal boosting circuitry may be required to reduce the resistance of the components capable of operating over the relatively wide voltage range. Summary of the Invention

[0008] In view of the foregoing, this disclosure provides a touch display device and a drive signal output circuit, as well as a drive signal output method for the touch display device. The touch display device and drive signal output circuit include elements capable of operating within a relatively narrow voltage range (e.g., medium voltage (MV)) to selectively output display drive signals and touch drive signals with different voltage levels to a panel.

[0009] According to one embodiment of this disclosure, a drive signal output circuit is provided, comprising: a display drive signal output circuit that operates within a first voltage range, receives a display drive signal having the first voltage range via a first terminal, and outputs a first signal to a panel based on the received display drive signal during a first time period; and a touch drive signal output circuit that operates within a second voltage range, receives a touch drive signal having the second voltage range via a second terminal, and outputs a second signal based on the received touch drive signal during a second time period different from the first time period.

[0010] According to another embodiment of this disclosure, a touch display device is provided, comprising: a touch control circuit that generates a touch synchronization signal; a power management circuit that receives the touch synchronization signal from the touch control circuit and outputs a display driving signal having a first voltage range based on the received touch synchronization signal; a touch modulation circuit that receives the touch synchronization signal from the touch control circuit and outputs a touch driving signal having a second voltage range based on the received touch synchronization signal; and a driving signal output circuit that receives the display driving signal having the first voltage range from the power management circuit, receives the touch driving signal having the second voltage range from the touch modulation circuit, outputs a first signal based on the received display driving signal during a first time period, and outputs a second signal based on the received touch driving signal during a second time period different from the first time period.

[0011] According to another embodiment of this disclosure, a method for outputting a drive signal for a touch display device is provided, the method comprising: receiving a display drive signal having a first voltage range from a power management circuit; receiving a touch drive signal having a second voltage range from a touch modulation circuit; outputting a first signal to a panel based on the received display drive signal during a first time period; outputting a second signal to the panel based on the received touch drive signal during a second time period different from the first time period; and performing a discharge to prevent the application of a voltage exceeding the breakdown voltage during at least a portion of a time period during which neither the first signal nor the second signal is output.

[0012] As described above, according to one embodiment of this disclosure, although the display drive signal and the touch drive signal have different voltage levels, a multiplexer (e.g., a readout (RO) channel (CH) multiplexer (MUX)) for the drive signal output circuit can be designed using only components with a relatively narrow operating range (e.g., medium voltage (MV) components).

[0013] Therefore, a touch display device with a relatively small area can be realized by using only components with a relatively narrow operating range, which makes it possible to reduce costs due to the reduction in the number of components.

[0014] Furthermore, by using only devices with a relatively narrow operating range to design the drive signal output circuit (e.g., source driver and touch readout IC (SRIC)), a channel multiplexer (CH MUX) is not required, eliminating the need for an additional external HV power supply and internal boost circuitry. This results in a relatively small resistance value in the touch modulation IC (TMIC) and eliminates the need for a MUX for selecting the display drive signal and the touch drive signal, thus reducing the size of the TMIC. Simple Explanation of the Diagram

[0015] Figure 1 is a configuration diagram of a display device according to one embodiment.

[0016] Figure 2 is a timing diagram illustrating a method for driving a touch display device according to one embodiment.

[0017] Figure 3 is a detailed configuration diagram of a touch display device according to one embodiment.

[0018] Figure 4 is a detailed configuration diagram of a touch display device according to one embodiment.

[0019] Figure 5 is a detailed configuration diagram of the drive signal output circuit according to one embodiment.

[0020] Figure 6 is a detailed configuration diagram of a drive signal output circuit according to one embodiment.

[0021] Figures 7A and 7B are detailed configuration diagrams of a voltage level converter according to one embodiment.

[0022] Figure 8 is a detailed configuration diagram of a drive signal output circuit according to one embodiment.

[0023] Figure 9 is a timing diagram illustrating a method for driving a touch display device according to one embodiment.

[0024] Figures 10A, 10B, 10C, 10D, 10E, and 10F are diagrams illustrating the operation of a drive signal output circuit at various time points according to one embodiment.

[0025] Figure 11 is a flowchart illustrating a method of operating a touch display device according to one embodiment. Implementation

[0026] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terminology used in this specification and claims is not limited to its common or dictionary meaning and should be interpreted as conforming to the meaning and concepts of the technical matters covered by this disclosure.

[0027] The configurations shown in the embodiments described in this specification and the accompanying drawings are preferred embodiments of this disclosure and do not represent all the technical ideas of this disclosure, such that various equivalents and modified examples that can replace the preferred embodiments may exist at the time of filing this application.

[0028] A touch display device according to one embodiment can perform display and touch recognition in a time-division manner, and may include a configuration in which display elements and touch recognition elements are shared in an embedded cell manner; however, this embodiment is not limited to a time-division method or an intra-cell method. For example, a touch display device according to an embodiment described below can be implemented in an on-cell method of an external method or an embedded method.

[0029] According to various embodiments, display and touch recognition of a touch display device can be implemented in separate operations. Here, display means representing a desired image by driving the pixels of the display panel, and touch recognition means recognizing the touch position on the display panel. Furthermore, a time-division method means alternating between display and touch recognition in different time domains.

[0030] Specifically, in the time-division method, display and touch recognition can be implemented by alternating operations on a frame-by-frame basis to form the image. That is, display and touch recognition can be performed alternately corresponding to multiple frames forming the image. Furthermore, in the time-division method, touch recognition can be implemented by performing it two or more times within each frame forming the image.

[0031] The intra-unit approach means that pixels in the display panel can be displayed and touch-recognized, and the components shared for this purpose can be components capable of providing capacitance for touch recognition, and can at least include connection points of the components. An example of a connection point could be a node COM for applying a common voltage, but is not limited to this, and various components can be used as connection points depending on the manufacturer's intention.

[0032] Referring to FIG1, one embodiment of this disclosure may include a timing controller (T-CON) 10, a source driver 12 (or display driver circuitry), a gate driver 14, a touch driver circuitry 16, and a panel 18. According to one embodiment, as shown in FIG3, which will be described later, the source driver 12 and the touch driver circuitry 16 may be configured as a single drive signal output circuit (e.g., a source driver and a touch readout IC (SRIC)).

[0033] The timing controller 10 is configured to provide display control signals to the source driver 12 and the gate driver 14 to perform display and touch recognition in a time-division manner, and is configured to provide touch control signals to the touch driving circuit 16.

[0034] The timing controller 10 can output display control signals including control signals such as source control signals, gate control signals, clock pulses, horizontal synchronization signals or vertical synchronization signals and switching signals SW.

[0035] The source driver 12 is configured to receive a source control signal included in the display control signal, generate a source drive signal corresponding to the source control signal, and provide the generated source drive signal to the pixels of the panel 18. The source driver 12 typically includes a latch, a digital-to-analog converter, and an output buffer, with buffer 20 in FIG. 1 corresponding to the output buffer. Here, the latch stores data according to the source control signal and provides the data to the digital-to-analog converter, and the digital-to-analog converter outputs an analog signal of a voltage corresponding to the input data. The output buffer sends the output of the digital-to-analog converter as a source drive signal to the pixels of the panel 18 via the source line SL.

[0036] Gate driver 14 receives a gate control signal included in the display control signal, generates a gate drive signal corresponding to the gate control signal, and provides the gate drive signal to the pixels of panel 18. Gate driver 14 typically includes an input buffer, a shift register, a voltage level converter, and an output buffer, and buffer 30 in FIG1 corresponds to the output buffer.

[0037] The input buffer receives the gate control signal and outputs it to the shift register. The shift register controls the generation of scan pulses (which are gate signals sent by the input buffer) sequentially in rows of panel 18. The voltage level converter changes the output voltage level of the shift register to a voltage level that enables the thin-film transistor (TFT) composed of switches M to be turned on and off. The output buffer changes the signal output from the voltage level converter to drive the gate line GL with an RC load and outputs the signal as a gate drive signal.

[0038] Switches 22 and 32 may be formed on source line SL and gate line GL respectively connected to buffer 20 forming the output terminal of source driver 12 and buffer 30 forming the output terminal of gate driver 14, and switches 22 and 32 may be configured to be included in the elements of source driver 12 and gate driver 14, or may be configured to be included in the elements of panel 18.

[0039] Switches 22 and 32 can be floated or turned on according to the switch signal SW output from the timing controller 10. When floating, switches 22 and 32 can prevent the source drive signal and gate drive signal from being sent to the source line SL and gate line GL. Conversely, when turned on, switches 22 and 32 send the source drive signal output from the source driver 12 and the gate drive signal output from the gate driver 14 to the source line SL and gate line GL, respectively.

[0040] Panel 18 includes a plurality of pixels formed at the intersection of source line SL and gate line GL, and each pixel includes a switch M and a liquid crystal element CL connected to the switch M. The switch M of each pixel is configured to switch the source drive signal sent from the source driver 12 via the source line SL using a gate drive signal sent from the gate driver 14 via the gate line GL, and send the switched source drive signal to the liquid crystal element CL.

[0041] The liquid crystal element CL has an optical shutter function that controls light transmission by controlling the twist of the internal liquid crystal according to the voltage applied to electrodes formed at both ends, and a capacitor is arranged between the electrodes. One side of the liquid crystal element CL is connected to a switch M, and a source drive signal sent from the switch M is applied to the liquid crystal element CL, while the other side is connected to a node COM with a common voltage applied. With this configuration, the liquid crystal element CL can be driven according to the state of the source drive signal based on the common voltage applied to the node COM.

[0042] According to various embodiments, a node COM can form a connection point for touch recognition, and a constant voltage provided from the touch driving circuit 16 can be applied to the node COM. Here, the constant voltage can correspond to a touch driving signal TDS provided from the touch driving circuit 16. The touch driving signal TDS includes a driving signal and a sensing signal, and the driving signal can be defined as a constant voltage applied to the node COM forming the connection point, and the sensing signal can be defined as a signal corresponding to the voltage change of the connection point according to touch. That is, the touch driving signal TDS according to various embodiments can include a driving signal and a sensing signal, wherein the driving signal is a constant voltage for driving the touch, and the sensing signal is a signal change sensed according to the touch. In various embodiments, a common voltage for display and a constant voltage for touch recognition (e.g., the touch driving signal TDS) can be applied alternately to the node COM.

[0043] The touch driving circuit 16 is configured to receive a touch control signal provided by the timing controller 10 and provide a touch driving signal TDS to the connection point of the pixel (i.e., the node COM of the pixel) according to the touch control signal.

[0044] In the above configuration, the liquid crystal in panel 18 includes pixels arranged in multiple columns and rows. Source driver 12 is configured to output source drive signals for each row of pixels, and gate driver 14 is configured to output gate drive signals for each column of pixels. Then, touch drive circuit 16 can be configured to provide touch drive signals TDS to the nodes COM of each row or column of pixels.

[0045] The embodiment of Figure 1 described above can be driven in a time-division manner by alternately assigning display and touch recognition to the continuous time domain as shown in Figure 2.

[0046] First, the timing controller 10 provides source control signals and gate control signals to the source driver 12 and gate driver 14, respectively, for display purposes. The timing controller 10 provides touch control signals to the touch driving circuit 16 to control the output of the touch driving signal TDS to not be activated in the time domain set for the display period.

[0047] In Figure 2, time T1 is the time point when the display state enters the touch recognition state, and time T2 is the time point when the touch recognition state enters the display state.

[0048] When the set time for representing the image has elapsed, the timing controller 10 performs control for touch recognition. That is, the timing controller 10 floats the source line SL and gate line GL connected to the pixel by floating switches 22 and 32 to perform touch recognition. One end of the liquid crystal element CL is floated by the control of switches 22 and 32 of the timing controller 10.

[0049] Then, the timing controller 10 activates the output of the touch drive signal TDS by providing a touch control signal to the touch drive circuit 16 for touch recognition. Under the control of the timing controller 10, the touch drive signal TDS with a constant voltage is applied to the node COM of each pixel.

[0050] In the above configuration, the timing controller 10 switches 22 and 32 to the floating state at a time point T11 that is earlier than time T1 (the time point when it is set to enter the touch recognition state from the display state), or at a time point T12 that is later than time T1.

[0051] The timing controller 10 can simultaneously or sequentially float the switch 22 on the source line SL and the switch 32 on the gate line GL. When the timing controller 10 floats the switches 22 and 32 sequentially, it can first float the switch 22 on the source line SL at time T11, and then float the switch 32 on the gate line GL at time T12. Conversely, the timing controller 10 can first float the switch 32 on the gate line GL at time T11, and then float the switch 22 on the source line SL at time T12. Here, the time period between T11 and T12 can be set as the floating period.

[0052] When the source drive signal and gate drive signal are applied to the source line SL and gate line GL respectively for display, considering the node COM connected to one side of the liquid crystal element CL, parasitic capacitances C1 formed in parallel with the liquid crystal element CL, parasitic capacitance C2 between the liquid crystal element CL and the gate line GL, parasitic capacitance C3 between the node COM with applied common voltage and the source line SL, and parasitic capacitance C4 between the node COM with applied common voltage and the gate line GL may occur. However, when the source line SL and gate line GL are floated for touch recognition, considering the node COM connected to one side of the liquid crystal element CL, parasitic capacitances in the pixel may not form.

[0053] Figure 3 is a detailed configuration diagram of a touch display device according to one embodiment. Referring to Figure 3, the touch display device may include a touch control circuit 310 (touch microcontroller unit (MCU)), a power management circuit 320 (power management IC (PMIC)), a touch modulation circuit 330 (touch modulation IC (TMIC)), a drive signal output circuit 340 (e.g., a source driver and a touch readout IC (SRIC)), and a panel 350. The drive signal output circuit 340 may include the functions of the source driver 12 and the touch drive circuit 16 described above with reference to Figure 1.

[0054] According to one embodiment, the touch control circuit 310 may provide a synchronization signal to the power management circuit 320, the touch modulation circuit 330, and the drive signal output circuit 340. The synchronization signal may include a synchronization signal for distinguishing between display periods and touch sensing periods, and may be referred to as a display synchronization signal or a touch synchronization signal. The touch control circuit 310 may be configured to include at least some of the functions of the timing controller 10 shown in FIG. 1, or may be replaced by the timing controller 10.

[0055] According to one embodiment, the power management circuit 320 can receive a synchronization signal (e.g., a touch synchronization signal) from the touch control circuit 310 and output a display drive signal Display VCOM based on the received synchronization signal. For example, the display drive signal may have a voltage of -1V.

[0056] According to one embodiment, the touch modulation circuit 330 may include a touch drive signal generator 331 and a first multiplexer 332. The touch modulation circuit 330 can generate a touch drive signal Touch VCOM by receiving a synchronization signal from the touch control circuit 310 and modulating the received synchronization signal. For example, the touch drive signal generator 331 can generate the touch drive signal based on a synchronization signal (e.g., a touch synchronization signal) received from the touch control circuit 310. According to one embodiment, the touch drive signal can be configured in the form of pulses having a voltage range of 1V to 4V. The first multiplexer 332 of the touch modulation circuit 330 receives the touch drive signal output from the touch drive signal generator 331 and the display drive signal output from the power management circuit 320, and selectively outputs one of the touch drive signal and the display drive signal. For example, the first multiplexer 332 can selectively output either the input display drive signal or the touch drive signal based on the synchronization signal provided from the touch control circuit 310. For example, during a display operation period for displaying an image on panel 350, the first multiplexer 332 may output a display drive signal, and during a touch sensing operation period for sensing a touch from panel 350, the first multiplexer 332 may output a touch drive signal. The display drive signal or touch drive signal output from the first multiplexer 332 of the touch modulation circuit 330 may be sent to the drive signal output circuit 340. The touch modulation circuit 330 may be configured to include at least some of the functions of the touch drive circuit 16 shown in FIG. 1, or may be replaced by the touch drive circuit 16.

[0057] According to one embodiment, the drive signal output circuit 340 may include a touch analog front end (AFE) 341, a high voltage (HV) level converter 342, and a second multiplexer 343. According to one embodiment, the HV level converter 342 of the drive signal output circuit 340 may receive a synchronization signal from the touch control circuit 310 and supply a VDD signal to the second multiplexer 343 based on the received synchronization signal. For example, since the signals input to the second multiplexer 343 include a display drive signal of a first voltage range and a touch drive signal of a second voltage range, the HV level converter 342 may supply an HV voltage level signal HVDD (e.g., 17V) to the second multiplexer 343.

[0058] The second multiplexer 343 of the drive signal output circuit 340 can selectively output a display drive signal within a first voltage range or a touch drive signal within a second voltage range based on the HV voltage level signal HVDD supplied from the HV voltage level converter 342. Additionally, the second multiplexer 343 may include a channel multiplexer and can selectively output drive signals for each channel corresponding to each pixel of the panel 350. In the embodiments described later, the function of the second multiplexer 343 selectively outputting drive signals for each channel will be omitted. For example, during a display operation period for displaying an image on the panel 350, the second multiplexer 343 can output a display drive signal to the panel 350, and during a touch sensing operation period for sensing a touch from the panel 350, the second multiplexer 343 can output a touch drive signal to the panel 350. According to one embodiment, during the touch sensing operation period, the second multiplexer 343 can receive a signal sensed from the panel 350 and supply that signal to the touch AFE 341. The touch AFE 341 can determine whether a touch has been performed based on signals sensed from the panel 350. The method by which the touch AFE 341 determines whether a touch has been performed can use known technologies, so its detailed description will be omitted.

[0059] According to one embodiment, since the second multiplexer 343 receives a display drive signal of a first voltage range (e.g., -1V) and a touch drive signal of a second voltage range (e.g., 1V to 4V) together via a single terminal, the second multiplexer 343 can be configured using elements capable of operating within a voltage range (e.g., HV (high voltage)) that includes both the first and second voltage ranges. For example, since the second multiplexer 343 includes HV elements, the cost and area of ​​the second multiplexer 343 may increase.

[0060] Figure 5 is a detailed configuration diagram of a drive signal output circuit according to one embodiment. Referring to Figure 5, the drive signal output circuit 340 may include an HV voltage level converter 342 and a second multiplexer 343. As described above, since the HV voltage level converter 342 needs to output HVDD (e.g., 17V), it may include an HV element. The second multiplexer 343 may include an HV element to simultaneously process a display drive signal within a first voltage range (e.g., -1V) and a touch drive signal within a second voltage range (e.g., 1V to 4V). For example, the second multiplexer 343 may include a first switch SW1 for outputting a touch drive signal and a second switch SW2 for outputting a display drive signal. The first switch may include a P-type transistor (e.g., a P-type metal-oxide-semiconductor field-effect transistor (MOSFET)) and an N-type transistor (e.g., an N-type MOSFET) connected in parallel with the P-type transistor. The second switch may include a P-type transistor and an N-type transistor connected in parallel with the P-type transistor. For example, the P-type or N-type transistors constituting the first or second switch can be configured using HV elements.

[0061] Figure 4 is a detailed configuration diagram of a touch display device according to one embodiment. Referring to Figure 4, the touch display device includes a touch control circuit 310 (e.g., a touch MCU (microcontroller unit)), a power management circuit 320 (e.g., a power management IC (PMIC)), a touch modulation circuit 430 (e.g., a touch modulation IC (TMIC)), a drive signal output circuit 440 (e.g., a source driver and a touch readout IC (SRIC)), and a panel 350. The drive signal output circuit 440 may include the functions of the source driver 12 and the touch drive circuit 16 described above with reference to Figure 1.

[0062] According to one embodiment, the touch control circuit 310 may provide a synchronization signal to the power management circuit 320, the touch modulation circuit 430, and the drive signal output circuit 440. The synchronization signal may include a synchronization signal for distinguishing between display periods and touch sensing periods, and may be referred to as a display synchronization signal or a touch synchronization signal. The touch control circuit 310 may be configured to include at least some of the functions of the timing controller 10 shown in FIG. 1, or may be replaced by the timing controller 10.

[0063] According to one embodiment, the power management circuit 320 can receive a synchronization signal (e.g., a touch synchronization signal) from the touch control circuit 310 and output a display drive signal Display VCOM based on the received synchronization signal. For example, the display drive signal may have a voltage of -1V.

[0064] According to one embodiment, the touch modulation circuit 430 may include a touch drive signal generator 431. The touch modulation circuit 430 can generate a touch drive signal Touch VCOM by receiving a synchronization signal from the touch control circuit 310 and modulating the signal based on the received synchronization signal. For example, the touch drive signal generator 431 can generate the touch drive signal based on a synchronization signal (e.g., a touch synchronization signal) received from the touch control circuit 310. According to one embodiment, the touch drive signal can be configured in the form of pulses having a voltage range of 1V to 4V. The touch drive signal output from the touch drive signal generator 431 of the touch modulation circuit 430 can be sent to a drive signal output circuit 440. The touch modulation circuit 430 can be configured to include at least some of the functions of the touch drive circuit 16 shown in FIG. 1, or can be replaced by the touch drive circuit 16.

[0065] According to one embodiment, the drive signal output circuit 440 may include a touch analog front end (AFE) 441, a medium voltage (MV) level converter 442, and a multiplexer 443. According to one embodiment, the MV level converter 442 of the drive signal output circuit 440 may receive a synchronization signal from the touch control circuit 310 and supply a VDD signal to the multiplexer 443 based on the received synchronization signal. For example, the signal input to the multiplexer 443 may include a display drive signal within a first voltage range and a touch drive signal within a second voltage range, and the MV level converter 442 may supply the multiplexer 443 with an MV voltage level signal PVDD (e.g., 6V) or NVDD (e.g., -6V).

[0066] The drive signal output circuit 440 can receive a display drive signal with a first voltage range (e.g., -1V) output from the power management circuit 320 via a first terminal, and a touch drive signal with a second voltage range (e.g., 1V to 4V) output from the touch modulation circuit 430 via a second terminal separate from the first terminal. The display drive signal received via the first terminal and the touch drive signal received via the second terminal can be input to the multiplexer 443 respectively.

[0067] According to one embodiment, multiplexer 443 can selectively output a display drive signal within a first voltage range or a touch drive signal within a second voltage range based on the MV voltage level signal PVDD or NVDD supplied from MV voltage level converter 442. Additionally, multiplexer 443 may include a channel multiplexer and can selectively output drive signals for each channel corresponding to each pixel of panel 350. In the embodiments described later, the function of multiplexer 443 selectively outputting drive signals for each channel will be omitted. For example, during a display operation period for displaying an image on panel 350, multiplexer 443 can output a display drive signal to panel 350, and during a touch sensing operation period for sensing a touch from panel 350, multiplexer 443 can output a touch drive signal to panel 350. According to one embodiment, during a touch sensing operation period, multiplexer 443 can receive signals sensed from panel 350 and supply the input signals to touch AFE 441. Touch AFE 441 can determine whether a touch has occurred based on the signals sensed from panel 350. Since the method for determining whether a touch has occurred by touching AFE 441 can use known techniques, its detailed description will be omitted.

[0068] According to an embodiment, the multiplexer 443 can receive a display drive signal of a first voltage range (e.g., -1V) and a touch drive signal of a second voltage range (e.g., 1V to 4V) via individual terminals, and can selectively output the display drive signal and the touch drive signal based on the MV voltage level signal PVDD (e.g., 6V) or NVDD (e.g., -6V) provided from the MV voltage level converter 442.

[0069] According to one embodiment, the multiplexer 443 may include separate circuitry (e.g., display drive signal output circuitry and touch drive signal output circuitry) for processing display drive signals and touch drive signals. Each of these circuits may be configured using an MV element having a relatively narrower voltage range than the HV element. For example, by processing signals of a first voltage range and signals of a second voltage range via separate circuitry, the multiplexer 443 may be configured using elements capable of operating in medium voltage MV.

[0070] Figure 6 is a detailed configuration diagram of a drive signal output circuit according to one embodiment. Referring to Figure 6, the drive signal output circuit 440 may include a first MV voltage level converter 442a, a second MV voltage level converter 442b, and a multiplexer 443. The first MV voltage level converter 442a may receive a logic signal (e.g., a 1.2V signal) to output a PVDD (e.g., a 6V) signal, and the second MV voltage level converter 442b may receive a logic signal (e.g., a 1.2V signal) to output an NVDD (e.g., a -6V) signal. An exemplary detailed circuit 610 of the first MV voltage level converter 442a and the second MV voltage level converter 442b will be described with reference to Figures 7A and 7B.

[0071] Figures 7A and 7B are detailed configuration diagrams of a voltage level converter according to one embodiment. Referring to Figure 7A, the first MV voltage level converter 610a may include a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, and a sixth switch SW6. The first switch SW1, the second switch SW2, and the sixth switch SW6 may include P-type transistors (e.g., P-type metal-oxide-semiconductor field-effect transistors (MOSFETs)). The third switch SW3, the fourth switch SW4, and the fifth switch SW5 may include N-type transistors (e.g., N-type MOSFETs).

[0072] According to one embodiment, when a PVDD voltage is applied to the gate terminal of the first switch SW1 and the gate terminal of the second switch SW2 is grounded, no current flows between the first switch SW1 and the second switch SW2. When the gate terminals of the fourth switch SW4 and the fifth switch SW5 are grounded, current flows through the fourth switch SW4 and the fifth switch SW5. Based on the above operation, an NVDD voltage can be applied to the output terminal connected between the second switch SW2 and the fourth switch SW4.

[0073] Referring to Figure 7B, the second MV voltage level converter 610b may include a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, and a sixth switch SW6. The first switch SW1, the second switch SW2, and the sixth switch SW6 may include P-type transistors (e.g., P-type metal-oxide-semiconductor field-effect transistors (MOSFETs)). The third switch SW3, the fourth switch SW4, and the fifth switch SW5 may include N-type transistors (e.g., N-type MOSFETs).

[0074] According to one embodiment, when the gate terminals of the first switch SW1 and the second switch SW2 are grounded, current flows through the first switch SW1 and the second switch SW2. When the gate terminal of the fourth switch SW4 is grounded and the NVDD voltage is applied to the gate terminal of the fifth switch SW5, no current flows through the fourth switch SW4 and the fifth switch SW5. Based on the above operation, the PVDD voltage can be applied to the output terminal connected between the second switch SW2 and the fourth switch SW4.

[0075] According to one embodiment, the first MV voltage level converter 610a and the second MV voltage level converter 610b of Figures 7A and 7B can be configured as identical circuits to switch and output PVDD and NVDD signals, or they can be configured as separate circuits to output NVDD and PVDD signals. The PVDD and NVDD signals output from the MV voltage level converter 442 can also be supplied as VDD signals for controlling the gates of the individual transistors included in the multiplexer 443.

[0076] As described above, because the MV voltage level converter 442 requires outputs PVDD (e.g., 6V) and NVDD (e.g., -6V), the MV voltage level converter 442 may include MV elements. According to the above configuration, the MV voltage level converter 442 may also exclude additional external HV power supplies and internal boost circuitry.

[0077] Figure 8 is a detailed configuration diagram of a drive signal output circuit according to one embodiment. Referring to Figure 8, the multiplexer 443 of the drive signal output circuit 440 may include a first switch SW1, a second switch SW2, and a third switch SW3, wherein the first switch SW1 is used to receive a touch drive signal Touch VCOM having a second voltage range (e.g., 1V to 4V), the second switch SW2 (connected in series with the first switch) is used to receive the touch drive signal from the first switch and output the second signal to the panel 350, and the third switch SW3 is connected between the first switch and the second switch. The first switch SW1, the second switch SW2, and the third switch SW3 may be referred to as the touch drive signal output circuit. The third switch SW3 may be controlled to discharge to prevent voltages exceeding the breakdown voltage from being applied to the first switch SW1 or the second switch SW2 for at least a portion of the time period when the second signal is not output by the second switch SW2. The operation of the touch drive signal output circuit will be described later with reference to Figures 9 and 10.

[0078] According to one embodiment, the first switch SW1 may include a P-type transistor and an N-type transistor connected in parallel with the P-type transistor. The second switch SW2 may include a P-type transistor and an N-type transistor connected in parallel with the P-type transistor. The third switch SW3 may include an N-type transistor.

[0079] According to an embodiment, the multiplexer 443 of the drive signal output circuit 440 may include a fourth switch SW4, a fifth switch SW5, and a sixth switch SW6. The fourth switch SW4 receives a display drive signal Display VCOM having a first voltage range (e.g., -1V). The fifth switch SW5 (connected in series with the fourth switch) receives the display drive signal from the fourth switch and outputs the first signal to the panel 350. The sixth switch SW6 is connected between the fourth switch SW4 and the fifth switch SW5. The fourth switch SW4, the fifth switch SW5, and the sixth switch SW6 may also be referred to as the display drive signal output circuit. The sixth switch SW6 can be controlled to discharge, preventing the application of a voltage exceeding the breakdown voltage to the fourth switch SW4 or the fifth switch SW5 during at least a portion of the time when the first signal is not output via the fifth switch SW5. The operation of the display drive signal output circuit will be described later with reference to Figures 9 and 10.

[0080] According to one embodiment, the fourth switch SW4 may include a P-type transistor and an N-type transistor connected in parallel with the P-type transistor. The fifth switch SW5 may include a P-type transistor and an N-type transistor connected in parallel with the P-type transistor. The sixth switch SW6 may include a P-type transistor.

[0081] The operation of the multiplexer 443 included in the drive signal output circuit 440 will be described in detail below with reference to Figures 9 and 10.

[0082] Figure 9 is a timing diagram illustrating a method of driving a touch display device according to one embodiment. Referring to Figure 9, the touch display may operate in display mode during time period "a", and in touch sensing mode during time periods "b", "c", "d", "e" and "f".

[0083] According to one embodiment, multiplexer 443 may output a display drive signal (e.g., -1V) during time period "a" and a toggle-shifted touch drive signal (e.g., 1V to 4V) during time period "d". Additionally, multiplexer 443 may be grounded during time periods "b", "c", "e", and "f", thus not outputting a signal. In the following description, for ease of description, time period "a" may be referred to as the display period, time periods "b" and "e" may be referred to as the ground (GND) discharge period, time periods "c" and "f" may be referred to as the floating period, and time period "d" may be referred to as the touch sensing period.

[0084] According to one embodiment, the multiplexer 443 can be controlled to operate as shown in FIG10A during time period "a", as shown in FIG10B during time period "b", as shown in FIG10C during time period "c", as shown in FIG10D during time period "d", as shown in FIG10E during time period "e", and as shown in FIG10F during time period "f".

[0085] For example, the multiplexer 443 of Figure 8 can be controlled such that voltages as shown in Table 1 are applied to the gate terminals of the first switch SW1, the second switch SW2, and the third switch SW3 included in the multiplexer 443.

[0086] [Table 1] model Time period SW1 (PMOS / NMOS) SW2 (PMOS / NMOS) SW3 (PMOS / NMOS) Output status Display mode a PVDD / GND GND / NVDD PVDD VCOM is displayed. Touch sensing mode b PVDD / GND GND / NVDD PVDD GND discharge c PVDD / GND GND / NVDD PVDD float d [GND / PVDD] [GND / PVDD] [GND] Touch VCOM e PVDD / GND GND / PVDD PVDD GND discharge f PVDD / GND GND / NVDD PVDD float

[0087] Additionally, the multiplexer 443 in Figure 8 can be controlled such that the voltages shown in Table 2 are applied to the gate terminals of the fourth switch SW4, the fifth switch SW5, and the sixth switch SW6 included in the multiplexer 443.

[0088] [Table 2] model Time period SW4 (PMOS / NMOS) SW5 (PMOS / NMOS) SW6 (PMOS / NMOS) Output status Display mode a [NVDD / GND] [NVDD / GND] [GND] VCOM is displayed. Touch sensing mode b GND / NVDD NVDD / GND NVDD GND discharge c GND / NVDD PVDD / GND NVDD float d GND / NVDD PVDD / GND NVDD Touch VCOM e GND / NVDD PVDD / GND NVDD GND discharge f GND / NVDD PVDD / GND NVDD float

[0089] The operations of Figures 10A through 10F will be described below with reference to Figures 9, 1, and 2. Referring to Figure 10A, the multiplexer 443 can output a display drive signal during time period "a". For example, during time period "a", a PVDD voltage is applied to the gate terminal of the P-type transistor of the first switch SW1, the gate terminal of the N-type transistor is grounded, the gate terminal of the P-type transistor of the second switch SW2 is grounded, and an NVDD voltage is applied to the gate terminal of the N-type transistor, such that no current flows through the first switch SW1 and the second switch SW2. The PVDD voltage can be applied to the gate terminal of the third switch SW3.

[0090] Additionally, during time period "a", the NVDD voltage is applied to the gate terminals of the P-type transistors of the fourth switch SW4 and the fifth switch SW5, and the gate terminals of the N-type transistors are grounded to allow current to flow through the fourth switch SW4 and the fifth switch SW5. Therefore, the multiplexer 443 can output a display drive signal (e.g., a -1V voltage signal).

[0091] Referring to Figure 10B, the multiplexer 443 can perform a discharge operation on the display drive signal during time period "b". For example, during time period "b", the gate terminal of the P-type transistor of the fourth switch SW4 switches from NVDD voltage to ground, applies NVDD voltage to the gate terminal of the N-type transistor which is in the ground state, and applies NVDD voltage to the gate terminal of the sixth switch SW6, so that current flows from the fifth switch SW5 through the ground GND of the sixth switch SW6 to discharge the display drive signal.

[0092] Referring to Figure 10C, the multiplexer 443 can remain in a floating state during time period "c". For example, during time period "c", the voltage applied to the gate terminal of the P-type transistor of the fifth switch SW5 changes from NVDD voltage to PVDD voltage, so that no current flows through the fourth switch SW4 and the fifth switch SW5 to maintain the floating state.

[0093] Referring to Figure 10D, the multiplexer 443 can output a touch drive signal and sense a touch signal during the time period "d". For example, during the time period "d", current flows through the first switch SW1 and the second switch SW2 because the gate terminals of the P-type transistors of the first switch SW1 and the second switch SW2 are grounded, and a PVDD voltage is applied to the gate terminals of the N-type transistors. The gate terminal of the third switch SW3 can be grounded. Therefore, the multiplexer 443 can output a transitional touch drive signal (e.g., a voltage signal from 1V to 4V).

[0094] Referring to Figure 10E, the multiplexer 443 can perform a discharge operation on the touch drive signal during time period "e". For example, during time period "e", a PVDD voltage is applied to the gate terminal of the P-type transistor of the first switch SW1 which is in a grounded state, and the gate terminal of the N-type transistor switches from the state of applying the PVDD voltage to the grounded state. The PVDD voltage is also applied to the gate terminal of the third switch SW3 which is in a grounded state, so that current can flow from the second switch SW2 through the ground GND of the first switch SW1 to discharge the touch drive signal.

[0095] Referring to Figure 10F, the multiplexer 443 can remain in a floating state during the time period "f". For example, during the time period "f", the voltage applied to the gate terminal of the N-type transistor of the second switch SW2 changes from PVDD voltage to NVDD voltage, and no current flows through the second switch SW2 and the third switch SW3 to maintain the floating state.

[0096] Figure 11 is a flowchart illustrating a method of operating a touch display device according to one embodiment. Referring to Figure 11, in the touch display device, the power management circuit outputs a display drive signal (step S1110) based on a synchronization signal (e.g., a display synchronization signal or a touch synchronization signal) received from the touch control circuit. The display drive signal may have a first voltage range (e.g., -1V).

[0097] Additionally, in the touch display device, the touch modulation circuit outputs a touch drive signal based on a synchronization signal (e.g., a display synchronization signal or a touch synchronization signal) received by the touch control circuit (step S1120). The touch drive signal may have a second voltage range (e.g., 1V to 4V).

[0098] In the touch display device, the drive signal output circuit receives the display drive signal from the power management circuit and the touch drive signal from the touch modulation circuit (step S1130).

[0099] In a touch display device, the drive signal output circuit outputs a first signal based on the display drive signal during a first time period (step S1140).

[0100] In the touch display device, the drive signal output circuit outputs a second signal based on the touch drive signal during the second time period (step S1150).

[0101] Cross-references to related applications

[0102] This application claims priority to Korean Patent Application No. 10-2021-0102895, filed on August 5, 2021, the entire contents of which are incorporated herein by reference.

[0103] 10: Timing Controller 12: Source driver, display driver circuit 14: Gate Driver 16: Touch driving circuit 18: Panel 20: Buffer 22: Switch 30: Buffer 32: Switch 310: Touch control circuit 320: Power Management Circuit 330: Touch modulation circuit 331: Touch drive signal generator 332: First Multiplexer 340: Drive signal output circuit 341: Touch Analog Front-end 342: High Voltage Level Converter 343: Second Multiplexer 350: Panel 430: Touch modulation circuit 431: Touch drive signal generator 440: Drive signal output circuit 441: Touch Analog Front-end 442: Medium Voltage Level Converter 442a: First MV voltage level converter 442b: Second MV voltage level converter 443: Multiplexer 610: Circuit 610a: First MV voltage level converter 610b: Second MV voltage level converter a: Time period b: Time period c: Time period C1: Parasitic capacitance C2: Parasitic capacitance C3: Parasitic capacitance C4: Parasitic capacitance CL: Liquid Crystal Element COM: Node d: Time period e: Time period f: Time period GL: Gate line GND: Grounding HVDD: Signal M: Switch NVDD: MV voltage level signal PMIC: Power Management IC PVDD: MV voltage level signal S1110: Steps S1120: Steps S1130: Steps S1140: Steps S1150: Steps SL: Source Line SRIC: Source Driver and Touch Reader IC SW: Switch signal SW1: First switch SW2: Second switch SW3: Third switch SW4: Fourth Switch SW5: Fifth Switch SW6: Sixth Switch T1: Time T2: Time T11: Time point, time T12: Time point, time T21: Time point, time T22: Time point, time TDS: Touch drive signal TMIC: Touch Modulation IC

Claims

1. A drive signal output circuit, comprising: A display driving signal output circuit operates within a first voltage range, receives a display driving signal having the first voltage range via a first terminal, and outputs a first signal to the panel based on the received display driving signal during a first time period; a touch driving signal output circuit operates within a second voltage range, receives a touch driving signal having the second voltage range via a second terminal, and outputs a second signal based on the received touch driving signal during a second time period different from the first time period; and a voltage level converter, wherein the voltage level converter is configured to: receive a logic signal having a predetermined voltage, convert the logic signal into a voltage having the first voltage range, and output the converted logic signal having the first voltage range to the display driving signal output circuit to selectively output the display driving signal to the panel according to the voltage having the first voltage range; and receive the logic signal, convert the logic signal into a voltage having the second voltage range, and output the converted logic signal having the second voltage range to the touch driving signal output circuit to selectively output the touch driving signal to the panel according to the voltage having the second voltage range. The logic signal after conversion in the first voltage range and the logic signal after conversion in the second voltage range are processed separately in the display driving signal output circuit and the touch driving signal output circuit, respectively, in independent signal paths that do not share the first voltage range and the second voltage range.

2. The drive signal output circuit according to claim 1 receives a touch synchronization signal from a touch control circuit, and selectively outputs the first signal or the second signal based on the received touch synchronization signal.

3. The drive signal output circuit according to claim 1, wherein, The touch drive signal output circuit includes: a first switch for receiving a touch drive signal having the second voltage range; a second switch connected in series with the first switch for receiving the touch drive signal from the first switch and outputting the second signal to the panel; and a third switch connected between the first switch and the second switch, wherein the third switch is controlled to discharge to prevent a voltage exceeding the breakdown voltage from being applied to the first switch or the second switch for at least some time periods when the second signal is not output by the second switch.

4. The drive signal output circuit according to claim 3, wherein, The first switch includes a P-type transistor and an N-type transistor connected in parallel with the P-type transistor, and the second switch includes a P-type transistor and an N-type transistor connected in parallel with the P-type transistor.

5. The drive signal output circuit according to claim 3, wherein, The third switch includes an N-type transistor.

6. The drive signal output circuit according to claim 1, wherein, The display drive signal output circuit includes: a fourth switch for receiving a display drive signal having the first voltage range; a fifth switch connected in series with the fourth switch for receiving the display drive signal from the fourth switch and outputting the first signal to the panel; and a sixth switch connected between the fourth switch and the fifth switch, wherein the sixth switch is controlled to discharge to prevent voltage exceeding the breakdown voltage from being applied to the fourth switch and the fifth switch for at least some time periods when the first signal is not output by the fifth switch.

7. The drive signal output circuit according to claim 6, wherein, The fourth switch includes a P-type transistor and an N-type transistor connected in parallel with the P-type transistor, and the fifth switch includes a P-type transistor and an N-type transistor connected in parallel with the P-type transistor.

8. The drive signal output circuit according to claim 6, wherein, The sixth switch includes a P-type transistor.

9. A touch display device, comprising: The touch control circuit generates a touch synchronization signal; A power management circuit receives the touch synchronization signal from the touch control circuit and outputs a display drive signal having a first voltage range based on the received touch synchronization signal; a touch modulation circuit receives the touch synchronization signal from the touch control circuit and outputs a touch drive signal having a second voltage range based on the received touch synchronization signal; and a drive signal output circuit receives the display drive signal having the first voltage range from the power management circuit, receives the touch drive signal having the second voltage range from the touch modulation circuit, outputs a first signal based on the received display drive signal during a first time period, and outputs a second signal based on the received touch drive signal during a second time period different from the first time period, wherein the drive signal output circuit includes a voltage level converter; wherein the voltage level converter is configured to: The system receives a logic signal having a predetermined voltage, converts the logic signal into a voltage having a first voltage range, and outputs the converted logic signal having the first voltage range to the drive signal output circuit to selectively output the display drive signal to the panel according to the voltage having the first voltage range; and receives the logic signal, converts the logic signal into a voltage having a second voltage range, and outputs the converted logic signal having the second voltage range to the drive signal output circuit to selectively output the touch drive signal to the panel according to the voltage having the second voltage range, wherein the converted logic signal in the first voltage range and the converted logic signal in the second voltage range are separate and processed in the drive signal output circuit in independent signal paths that do not share the first voltage range and the second voltage range.

10. The touch display device according to claim 9, wherein, The drive signal output circuit receives the touch synchronization signal from the touch control circuit, and selectively outputs the first signal or the second signal based on the received touch synchronization signal.

11. The touch display device according to claim 9, wherein, The drive signal output circuit receives a display drive signal with the first voltage range output from the power management circuit via a first terminal, and receives a touch drive signal with the second voltage range output from the touch modulation circuit via a second terminal.

12. The touch display device according to claim 11, wherein, The drive signal output circuit includes: a display drive signal output circuit that operates within a first voltage range, receives a display drive signal having the first voltage range, and outputs the first signal to the panel based on the touch synchronization signal; and a touch drive signal output circuit that operates within a second voltage range, receives a touch drive signal having the second voltage range, and outputs the second signal to the panel based on the touch synchronization signal.

13. The touch display device according to claim 12, wherein, The touch drive signal output circuit includes: a first switch for receiving a touch drive signal having the second voltage range; a second switch connected in series with the first switch for receiving the touch drive signal from the first switch and outputting the second signal to the panel; and a third switch connected between the first switch and the second switch, wherein the third switch is controlled to discharge to prevent a voltage exceeding the breakdown voltage from being applied to the first switch or the second switch for at least some time periods when the second signal is not output by the second switch.

14. The touch display device according to claim 13, wherein, The second voltage range includes 1V to 4V.

15. The touch display device according to claim 12, wherein, The display drive signal output circuit includes: a fourth switch for receiving a display drive signal having the first voltage range; a fifth switch connected in series with the fourth switch for receiving the display drive signal from the fourth switch and outputting the first signal to the panel; and a sixth switch connected between the fourth switch and the fifth switch, wherein the sixth switch is controlled to discharge to prevent voltage exceeding the breakdown voltage from being applied to the fourth switch and the fifth switch for at least some time periods when the first signal is not output by the fifth switch.

16. The touch display device according to claim 15, wherein, The first voltage range includes -1V.

17. A method for outputting a driving signal for a touch display device, the method comprising: Receive a display drive signal with a first voltage range from the power management circuit; Receive a touch drive signal with a second voltage range from the touch modulation circuit; The process includes: outputting a first signal to a panel based on a received display driving signal during a first time period; outputting a second signal to the panel based on a received touch driving signal during a second time period different from the first time period; and performing a discharge to prevent the application of a voltage exceeding the breakdown voltage during at least some time periods when neither the first signal nor the second signal is output. Specifically, outputting the first signal to the panel based on the received display driving signal during the first time period includes: receiving a logic signal having a predetermined voltage; converting the logic signal into a voltage having a first voltage range; and outputting the converted logic signal having the first voltage range to a multiplexer to selectively output the display driving signal to the panel according to the voltage having the first voltage range. Similarly, outputting the second signal to the panel based on the received touch driving signal during the second time period includes: receiving the logic signal; converting the logic signal into a voltage having a second voltage range; and outputting the converted logic signal having the second voltage range to the multiplexer to selectively output the touch driving signal to the panel according to the voltage having the second voltage range. The logic signal after conversion in the first voltage range and the logic signal after conversion in the second voltage range are processed separately in the multiplexer in independent signal paths that are not used together in the first voltage range and the second voltage range.

18. The drive signal output method according to claim 17, wherein, The system receives a touch synchronization signal from the touch control circuit and selectively outputs either the first signal or the second signal based on the received touch synchronization signal.

19. The drive signal output method according to claim 17 further includes: A second switch connected in series with the first switch outputs a touch drive signal received from the first switch to the panel. A third switch connected between the first switch and the second switch is controlled to discharge such that a voltage exceeding the breakdown voltage is not applied to the first switch or the second switch for at least some time periods when the second signal is not output via the second switch.

Images