Display driving device and method for generating supply voltage thereof

Abstract

The invention provides a display driving device and a method for generating a supply voltage thereof. The display driving device comprises a control circuit and a voltage generating circuit. The control circuit judges the load state of the display driving device according to the time sequence control information and generates an index signal according to the load state. The voltage generating circuit generates a supply voltage according to a reference voltage. The voltage generating circuit raises the voltage value of the supply voltage by raising the voltage value of the reference voltage according to the index signal, or raises the working current according to the index signal.

Description

Technical Field

[0001] The present invention relates to a display driving device and a method for generating a supply voltage thereof, and in particular to a display driving device capable of performing compensation in response to a load state change and a method for generating a supply voltage thereof. Background Art

[0002] As user demands increase, the resolution and frame rate of touch displays are gradually improved. When using touch displays with high resolution and high frame rate, the digital components inside the circuit require considerable power consumption. In the prior art, the working voltage of the digital circuit is often supplied by an external circuit, thereby saving the power consumption of the digital circuit. However, this working voltage supplied by the external circuit cannot meet the power supply requirements of the display driver during the light-load and heavy-load switching. In addition, the response speed of the externally supplied working voltage will be limited by the bandwidth of the power management chip and the trace impedance of the printed circuit board, resulting in insufficient working voltage supplied to the circuit and abnormal data operations in the digital circuit. Summary of the invention

[0003] The present invention is directed to a display driving device and a method for generating a supply voltage thereof, which can reduce the jitter state of the supply voltage caused by load changes.

[0004] According to an embodiment of the present invention, a display driving device includes a control circuit and a voltage generating circuit. The control circuit determines the load state of the display driving device according to the timing control information, and generates an indicator signal according to the load state, wherein the indicator signal is used to indicate the time point when the load state rises from the first load to the second load. The voltage generating circuit is coupled to the control circuit. The voltage generating circuit generates a supply voltage according to a reference voltage. The voltage generating circuit raises the voltage value of the supply voltage by raising the voltage value of the reference voltage according to the indicator signal, or the voltage generating circuit raises the operating current according to the indicator signal.

[0005] According to an embodiment of the present invention, a method for generating a supply voltage includes: determining a load state of a display driving device according to timing control information; generating an indicator signal according to the load state, wherein the indicator signal is used to indicate a time point when the load state rises from a first load to a second load; providing a voltage generating circuit to generate a supply voltage according to a reference voltage; and according to the indicator signal, raising the voltage value of the supply voltage by raising the voltage value of the reference voltage, or, raising the operating current of the voltage generating circuit according to the indicator signal.

[0006] Based on the above, the display driving device of the present invention monitors the change of the load state of the display driving device through the control circuit, and when the load state of the display driving device is increased, by raising the voltage value of the supply voltage or raising the working current of the voltage generating circuit, the voltage drop state of the supply voltage caused by the increase of the load state can be effectively reduced, the voltage value of the supply voltage is effectively stabilized, and the working performance of the logic circuit operating based on the supply voltage is stabilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A schematic diagram showing a display driving device according to an embodiment of the present invention;

[0008] Figure 2A A schematic diagram showing an implementation of a voltage generating circuit of a display driving device according to an embodiment of the present invention;

[0009] Figure 2B A schematic diagram showing an implementation of a reference voltage generator according to an implementation of the present invention;

[0010] Figure 2C Showing the present invention Figure 2A A schematic diagram of an operation waveform of a reference voltage generator according to an embodiment;

[0011] Figure 3A A schematic diagram showing another embodiment of a voltage generating circuit of a display driving device of the present invention;

[0012] Figure 3B The present invention shown Figure 3A A schematic diagram of an operation waveform of a reference voltage generator according to an embodiment;

[0013] Figure 4 A waveform diagram showing a display driving device according to an embodiment of the present invention when performing a touch display action;

[0014] Figure 5 A schematic diagram showing a touch display according to an embodiment of the present invention;

[0015] Figure 6 A flow chart showing a method for generating a supply voltage according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0016] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0017] Please refer to Figure 1 , Figure 1A schematic diagram of a display driving device according to an embodiment of the present invention is shown. The display driving device 100 includes a control circuit 110 and a voltage generating circuit 120, which are used to drive the display to perform a touch display action. The control circuit 110 and the voltage generating circuit 120 are coupled to each other. The control circuit 110 receives display image data VDI. The control circuit 110 is used to perform timing control actions of display and touch detection of the display driving device 100. The control circuit 110 can generate timing control information corresponding to the timing control actions of display and touch detection, and judge the load state of the display driving device 100 according to the timing control information, and then generate the indicator signal FG according to the change of the load state of the display driving device 100.

[0018] In detail, in this embodiment, the display and touch detection action timing of the display driver 100 includes a vertical edge time interval, a touch detection time interval or a display time interval, wherein the vertical edge time interval includes a vertical front porch (vertical front porch, VFP) time interval and a vertical back porch (vertical back porch, VBP) time interval. In the vertical edge time interval, based on the display performing relatively few actions, the display driver 100 is in a light load state; in the touch detection time interval, based on the display performing medium-level actions, the display driver 100 is in a sub-light load state; in the display time interval, based on the display performing the most actions, the display driver 100 is in a heavy load state.

[0019] Furthermore, the control circuit 110 may generate the indicator signal FG in response to the change of the load state of the display driving device 100. When the load state of the display driving device 100 is increased, the control circuit 110 may enable the generated indicator signal FG. For example, when the load state of the display driving device 100 changes from a light load state to a sub-light load state or a heavy load state, the control circuit 110 may enable the indicator signal FG to be a logic value 1, and maintain the indicator signal FG at the logic value 1 for a period of time.

[0020] In addition, the voltage generating circuit 120 can generate the supply voltage VSUP based on a reference voltage. Furthermore, the voltage generating circuit 120 can increase the voltage value of the supply voltage VSUP by increasing the voltage value of the reference voltage in the first embodiment of the present invention according to the indicator signal FG. Alternatively, in the second embodiment of the present invention, the voltage generating circuit 120 can increase the operating current to speed up the response speed of the supply voltage VSUP according to the indicator signal FG.

[0021] In the first embodiment of the present invention, by raising the voltage value of the reference voltage, the voltage generating circuit 120 can correspondingly increase the voltage value of the generated supply voltage VSUP. In this way, the decrease of the supply voltage VSUP can be effectively suppressed in response to the increase of the load state, and the stability of the voltage value of the supply voltage VSUP can be improved.

[0022] In the second embodiment of the present invention, the voltage generating circuit 120 increases the operating current to speed up the response speed of the supply voltage VSUP. In this way, the supply voltage VSUP can be quickly adjusted in response to the increase in the load state, and the stability of the voltage value of the supply voltage VSUP can also be improved.

[0023] Incidentally, the designer may set the length of the time interval during which the indicator signal FG is maintained at the logic value 1 based on the stabilization time of the supply voltage VSUP in response to the disturbance caused by the increase in the load state, and thereby optimize the power consumption of the display driving device. Here, since the stabilization time of the supply voltage VSUP when the load state is converted from a light load to a sub-light load is greater than the stabilization time of the supply voltage VSUP when the load state is converted from a light load to a heavy load, the length of the time interval during which the indicator signal FG is maintained at the logic value 1 when the load state is converted from a light load to a sub-light load may be less than the length of the time interval during which the indicator signal FG is maintained at the logic value 1 when the load state is converted from a light load to a sub-light load.

[0024] Please refer to Figure 2A , Figure 2A A schematic diagram showing an implementation of a voltage generating circuit of a display driving device according to an embodiment of the present invention is shown. The voltage generating circuit 200 includes an operational amplifier 210, a transistor 220, and a reference voltage generator 230. The positive input terminal of the operational amplifier 210 receives a reference voltage VREF; the negative input terminal of the operational amplifier 210 receives a feedback voltage VFB; the output terminal of the operational amplifier 210 generates a voltage GN to drive the transistor 220. The transistor 220 may be an N-type power transistor, a first terminal of which receives a power supply voltage VPP; the control terminal of the transistor 220 is coupled to the output terminal of the operational amplifier 210; and the second terminal of the transistor 220 generates a supply voltage VSUP.

[0025] It is worth noting that the feedback voltage VFB can be generated according to the supply voltage VSUP. Figure 2A In an embodiment of the present invention, the supply voltage VSUP may be directly provided to the negative input terminal of the operational amplifier 210 as the feedback voltage VFB. Under such conditions, the voltage value of the supply voltage VSUP may be equal to the reference voltage VREF.

[0026] In addition, the reference voltage generator 230 is coupled to the positive input terminal of the operational amplifier 210 and is used to provide a reference voltage VREF. The reference voltage generator 230 can receive the indicator signal FG and raise the voltage value of the reference voltage VREF from the first voltage V1 to the second voltage V2 according to the indicator signal FG. When the indicator signal FG is enabled, the voltage value of the reference voltage VREF remains equal to the second voltage.

[0027] When the voltage value of the reference voltage VREF is raised from the first voltage V1 to the second voltage V2, the voltage value of the supply voltage VSUP can also be correspondingly raised from the first voltage V1 to the second voltage V2. In this way, when the load state of the display driving device changes, the voltage value of the supply voltage VSUP can be appropriately raised in response to the change of the load state. The stabilization time of the jitter of the supply voltage VSUP can be effectively reduced to ensure that the corresponding logic circuit can operate correctly.

[0028] Please refer to Figure 2B Schematic diagram of an embodiment of a reference voltage generator according to an embodiment of the present invention is shown. The reference voltage generator 230 includes a voltage selector 231. The voltage selector 231 is used to select one of a plurality of candidate voltages V1 and V2 according to an indicator signal FG to generate a reference voltage VREF. The voltage values ​​of the candidate voltages V1 and V2 are different.

[0029] Please refer to Figure 2C The present invention shown Figure 2A A schematic diagram of the action waveform of the reference voltage generator of the embodiment. When the control circuit detects that the load state of the display driving device is about to change from a light load state to a heavy load state, the control circuit can make the generated indicator signal FG change state to an enable state of logic value 1 before an offset time ts when the load state changes. In response to the change of the indicator signal FG, the voltage value of the reference voltage VREF is appropriately raised, and a compensation mechanism is performed for the generated supply voltage VSUP.

[0030] In addition, the supply voltage VSUP in the present invention Figure 2A Under the compensation mechanism of the embodiment, the voltage jitter state is as shown in waveform C2. Without the above compensation mechanism, the voltage jitter state is as shown in waveform C1. Figure 2A Under the compensation mechanism of the embodiment, the jitter amplitude of the supply voltage VSUP is effectively limited, and the stabilization time of the voltage jitter is also effectively reduced.

[0031] Please refer to the following Figure 3A , Figure 3AA schematic diagram of another embodiment of a voltage generating circuit of a display driving device of the present invention is shown. The voltage generating circuit 300 includes an operational amplifier 310 and a transistor 320. The positive input terminal of the operational amplifier 310 receives a reference voltage VREF; the negative input terminal of the operational amplifier 310 receives a feedback voltage VFB; the output terminal of the operational amplifier 310 generates a voltage GN to drive the transistor 320. The transistor 320 can be an N-type power transistor, a first terminal of which receives a power supply voltage VPP; the control terminal of the transistor 320 is coupled to the output terminal of the operational amplifier 310; the second terminal of the transistor 320 generates a supply voltage VSUP. In this embodiment, the supply voltage VSUP generates a feedback voltage VFB through a feedback path constructed by a resistor R.

[0032] and Figure 2A The implementation method is different. In this implementation method, the voltage value of the reference voltage VREF may not be adjusted according to the indicator signal FG. In addition, the operational amplifier 310 has a bias current source IB, wherein the bias current source IB is used to determine the operating current provided by the voltage generating circuit 300. The bias current source IB is controlled by the indicator signal FB. When the indicator signal FB is in a disabled state, the bias current source IB generates a relatively low bias current and enables the voltage generating circuit 300 to provide a relatively low operating current. At this time, the current value of the bias current provided by the bias current source IB can be set to meet the requirements of light load use. When the indicator signal FB is in an enabled state, the bias current source IB can generate a relatively high bias current and enable the voltage generating circuit 300 to provide a relatively high operating current.

[0033] That is, when the display driving device enters a non-light load state, the voltage generating circuit 300 can improve the response speed of the generated supply voltage VSUP by providing a relatively high operating current.

[0034] Please refer to Figure 3B The present invention shown Figure 3A Schematic diagram of the action waveform of the reference voltage generator of the embodiment. When the control circuit detects that the load state of the display driving device is to be converted from a light load state to a heavy load state, the control circuit can make the generated indicator signal FG transition to an enable state of logic value 1 before an offset time ts when the load state is converted. Corresponding to the transition of the indicator signal FG, the bias current IB1 generated by the bias current source IB can be appropriately increased by an offset value dI, and a compensation mechanism is performed for the response speed of the generated supply voltage VSUP.

[0035] In addition, the supply voltage VSUP in the present invention Figure 3AUnder the compensation mechanism of the embodiment, the voltage jitter state is as shown in waveform C3. Without the above compensation mechanism, the voltage jitter state is as shown in waveform C1. Here, it can be clearly found that in the present invention Figure 3A Under the compensation mechanism of the embodiment, based on the response speed of increasing the supply voltage VSUP, the jitter amplitude of the supply voltage VSUP is effectively limited, and the stabilization time of the voltage jitter is also effectively reduced.

[0036] Please refer to Figure 4 , Figure 4 The waveform diagram of the display driving device of an embodiment of the present invention when performing a touch display action is shown. Among them, when the vertical synchronization signal Vsync is a relatively high voltage value, it can represent that the touch display is in the vertical front time interval VFP or the vertical back time interval VBP. Correspondingly, the control circuit can determine whether the display driving device is in the vertical edge time interval PT, the touch detection time interval TT or the display time interval DT according to the timing control information TSHD. Among them, when the display driving device is in the vertical edge time interval PT, its load state is a light load state LL1; when the display driving device is in the touch detection time interval TT, its load state is a second light load state LL2; and when the display driving device is in the display time interval DT, its load state is a heavy load state HL.

[0037] The control circuit further generates an indicator signal FG according to the load state of the display driving device. The indicator signal FG may have different information corresponding to the display driving device switching from the vertical edge time interval PT to the display time interval DT, or switching from the touch detection time interval TT to the display time interval DT. The indicator signal FG may contain information on voltage or current changes (or information on simultaneous changes in voltage and current) corresponding to different load state changes and information on the maintenance time. The voltage generating circuit in the display driving device may also execute the following when the indicator signal FG is enabled: Figure 2A or Figure 3A The compensation action proposed in the embodiment can improve the jitter state of the supply voltage VSUP. Among them, waveform C41 is the waveform of the supply voltage VSUP without performing the compensation action of the embodiment of the present invention; waveform C42 is the waveform of the supply voltage VSUP with performing the compensation action of the embodiment of the present invention. It can be seen that by performing the compensation action of the embodiment of the present invention, Figure 2A or Figure 3A The compensation action proposed in the embodiment can significantly improve the voltage stability of the supply voltage VSUP.

[0038] Please refer to the following Figure 5 , Figure 5A schematic diagram of a touch display according to an embodiment of the present invention is shown. The touch display 500 includes a control circuit 510, an analog circuit 501, and a panel 540. The control circuit 510 may be a digital circuit, including a data receiving circuit 511, a memory 512, an operation circuit 513, a timing controller 514, and a command buffer 515. The data receiving circuit 511 is used to receive display image data VDI, and store the received display image data VDI in the memory 512. The data receiving circuit 511 is, for example, a Mobile Industry Processor Interface (MIPI) circuit. The memory 512 may be any form of graphic RAM (GRAM).

[0039] The operation circuit 513 is used to read the display data from the memory 512 and perform operation operations on the display data, such as decompression of the display data. The timing control circuit 514 generates a plurality of operation commands according to the timing control information, and can store the operation commands in the command buffer 515 and generate the indicator signal FG. In addition, the timing control circuit 514 can send a read command RD to the memory 512, and read the display data in the memory 512 to the operation circuit 513.

[0040] The analog circuit 501 includes a driver 530 and a voltage generating circuit 520. The voltage generating circuit 520 can be coupled to the command buffer 515 to receive the indicator signal FG. The implementation details of the voltage generating circuit 520 have been described in detail in the aforementioned embodiments and implementation methods, and will not be repeated here. The driver 530 is used to sequentially drive the panel 540 according to the display data that has been sorted provided by the timing control circuit 514. The panel 540 can be a display panel or an integrated touch display panel.

[0041] In this embodiment, the supply voltage generated by the voltage generating circuit 520 can be used as the working power supply of each component in the control circuit 510. When the touch display 500 is in the display time interval, all circuit components (including the data receiving circuit 511, the memory 512, the operation circuit 513, the timing controller 514, the command buffer 515 and other peripheral circuits) need to operate, and the power consumption of the control circuit 510 is a heavy load (100%). In the touch detection time interval, the data receiving circuit 511 needs to perform the action of transferring the display image data VDI to the memory 512, and the power consumption of the control circuit 510 is a sub-light load (about 20%). In the vertical edge time interval, the data receiving circuit 511 does not perform the receiving action of the display image data VDI, and the control circuit 510 is a light load (about 5%).

[0042] Please refer to Figure 6 , Figure 6 A flow chart of a method for generating a supply voltage according to an embodiment of the present invention is shown. In step S610, a voltage generating circuit generates a supply voltage according to a reference voltage. In step S620, a load state of a display driving device is determined according to timing control information. In step S630, an indicator signal is generated according to the load state, wherein the indicator signal is used to indicate a time point when the load state rises from a first load to a second load. In step S640, the voltage value of the supply voltage can be raised by raising the voltage value of the reference voltage according to the indicator signal, or the operating current of the voltage generating circuit can be raised according to the indicator signal.

[0043] The implementation methods and implementation details of the above steps are described in detail in the aforementioned embodiments and implementation methods, and will not be elaborated here.

[0044] In summary, in the display driving device of the present invention, the control circuit determines the change of the load state of the display driving device through the action process of the touch display. Moreover, when the load state of the display driving device is increased, the voltage generating circuit can effectively reduce the state of the supply voltage decreasing due to the increase of the load state by raising the voltage value of the supply voltage or the response speed of the raised supply voltage in real time, effectively stabilize the voltage value of the supply voltage, and stabilize the working performance of the logic circuit operating based on the supply voltage.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display driving device, comprising: A control circuit, which determines a load state of the display driving device according to the timing control information, and generates an indicator signal according to the load state, wherein the indicator signal is used to indicate a time point when the load state is increased; as well as The voltage generating circuit is coupled to the control circuit to generate a supply voltage according to a reference voltage. The voltage generating circuit raises the voltage value of the supply voltage by raising the voltage value of the reference voltage according to the indicator signal, or the voltage generating circuit raises the operating current according to the indicator signal.

2. The display driving device according to claim 1, wherein the voltage generating circuit comprises: an operational amplifier having a positive input terminal for receiving the reference voltage, and a negative input terminal for receiving a feedback voltage generated according to the supply voltage; as well as The transistor has a first terminal receiving a power supply voltage, an output terminal of the transistor generating the supply voltage, and a control terminal of the transistor coupled to the output terminal of the operational amplifier.

3. The display driving device according to claim 2, wherein the voltage generating circuit further comprises: The reference voltage generator is coupled between the control circuit and the positive input terminal of the operational amplifier, and increases the reference voltage from a first voltage value to a second voltage value according to the indicator signal. 4 . The display driving device according to claim 3 , wherein the reference voltage generator comprises a voltage selector for selecting one of a plurality of candidate voltages according to the indicator signal to generate the reference voltage, wherein the voltage values ​​of the plurality of candidate voltages are different. 5 . The display driving device according to claim 2 , wherein at a time point when the load state is increased, a voltage value of the feedback voltage is smaller than a voltage value of the supply voltage. 6 . The display driving device according to claim 2 , wherein the operational amplifier increases a bias current according to the indicator signal, and the bias current is used to adjust the operating current.

7. The display driving device according to claim 1, wherein the timing control information indicates that the touch display is a vertical edge time interval, a touch detection time interval or a display time interval, wherein: The vertical edge time interval corresponds to a light load state, the touch detection time interval corresponds to a second light load state, and the display time interval corresponds to a heavy load state. 8 . The display driving device according to claim 7 , wherein the control circuit enables the indicator signal in response to the sub-light load state and the heavy load state. 9 . The display driving device according to claim 8 , wherein an enabling time interval of the indicator signal is earlier than a corresponding occurrence time offset time of the sub-light load state or the heavy load state. 10 . The display driving device according to claim 7 , wherein the control circuit sets the maintenance time information of the enable state in the indicator signal according to the change of the load state. 11 . The display driving device according to claim 7 , wherein the control circuit sets voltage and / or current change information in the indicator signal according to a change in the load state.

12. The display driving device according to claim 1, wherein the control circuit comprises: A data receiving circuit receives display image data; A memory, storing the display image data and outputting the display data according to the read flag; an operation circuit, which reads the display data from the memory and performs an operation on the display data; A timing control circuit generates a plurality of operation commands according to the timing control information; as well as The command buffer stores the plurality of operation commands and outputs the indicator signal.

13. A method for generating a supply voltage, comprising: determining a load state of a display driving device according to the timing control information; generating an indicator signal according to the load state, wherein the indicator signal is used to indicate a time point at which the load state is increased; Providing a voltage generating circuit to generate a supply voltage according to a reference voltage; as well as According to the indicator signal, the voltage value of the supply voltage is increased by increasing the voltage value of the reference voltage, or, according to the indicator signal, the operating current of the voltage generating circuit is increased.

14. The method for generating a supply voltage according to claim 13, further comprising: The reference voltage is increased from a first voltage value to a second voltage value according to the indicator signal.

15. The method for generating a supply voltage according to claim 13, further comprising: adjusting the bias current higher according to the indicator signal; as well as The operating current of the supply voltage generating circuit is adjusted according to the bias current.

16. The method for generating a supply voltage according to claim 13, wherein the timing control information indicates that the touch display is a vertical edge time interval, a touch detection time interval or a display time interval, wherein the vertical edge time interval corresponds to a light load state, the touch detection time interval corresponds to a sub-light load state, and the display time interval corresponds to a heavy load state.

17. The method for generating a supply voltage according to claim 16, further comprising: The indicator signal is enabled corresponding to the sub-light load state and the heavy load state.

18. The method for generating a supply voltage according to claim 17, further comprising: The enabling time interval of the indicator signal is made earlier than the corresponding occurrence time offset time of the sub-light load state or the heavy load state.

19. The method for generating a supply voltage according to claim 16, further comprising: According to the change of the load state, the maintenance time information of the indicator signal to the enabled state is set.

20. The method for generating a supply voltage according to claim 16, further comprising: The voltage and / or current change information in the indicator signal is set according to the change of the load state.

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