CN107610632B - Display driving circuit, power management device, display apparatus and driving method thereof - Google Patents
Display driving circuit, power management device, display apparatus and driving method thereof Download PDFInfo
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- CN107610632B CN107610632B CN201710890449.3A CN201710890449A CN107610632B CN 107610632 B CN107610632 B CN 107610632B CN 201710890449 A CN201710890449 A CN 201710890449A CN 107610632 B CN107610632 B CN 107610632B
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Abstract
The invention discloses a display driving circuit, a power supply management device, display equipment and a driving method thereof, and belongs to the field of display. The display driving circuit comprises a power management module, the power management module has a positive voltage output end, and the display driving circuit further comprises: the first end of the capacitor is connected with the positive voltage output end; a pull-down module connected to the second terminal of the capacitor for treating the second terminal of the capacitor as a reference voltage before the display driving circuit receives the shutdown signal; and the pull-up module is connected with the second end of the capacitor and used for conducting the second end of the capacitor to the first voltage line when the display driving circuit receives a shutdown signal, and the voltage on the first voltage line is greater than the reference voltage. The invention can relieve the abnormal condition caused by the over-high descending speed of the related voltage during shutdown, and is beneficial to improving the quality and performance of the product.
Description
Technical Field
The present invention relates to the field of display, and in particular, to a display driving circuit, a power management device, a display device, and a driving method thereof.
Background
In a conventional display device, a Power Management Module (PMM) includes a voltage conversion circuit, such as a DC-DC Converter (DC-DC Converter), which is mainly used to convert a Power voltage into various voltages required by other components, such as a digital positive voltage (AVDD) required by a Timing Controller (TCON), a Gate Driver (Gate Driver) and a Source Driver (Source Driver), a Gate high Voltage (VGH) and a Gate low Voltage (VGL) required by the Gate Driver, a common Voltage (VCOM) required by a display panel, and the like. During the shutdown process of the display device, the power management module losing power supply will utilize the charge stored in the capacitor to supply power to other components for a short time, so that the relevant components complete operations such as shutdown and screen clearing.
However, in some application scenarios, the voltage drop speed at some positive voltage output terminals of the power management module may be too fast, which may easily cause the voltage obtained by the relevant components to drop below the minimum allowable voltage before the shutdown operation is completed. For example, when the pixel is turned off, the gate driver needs to output a high gate voltage to each gate line of the row under the trigger of the full-on control signal (XON) to return all the pixels to the reset state. However, the gate high voltage may drop below the minimum allowable voltage too early, which may cause some pixels not to return to the reset state completely, causing the defects of shutdown ghost.
Disclosure of Invention
The invention provides a display driving circuit, a power supply management device, a display device and a driving method thereof, which can relieve abnormal conditions caused by too high descending speed of related voltage during shutdown.
In a first aspect, the present invention provides a display driving circuit, which includes a power management module having a positive voltage output terminal, and further includes:
a capacitor, a first end of the capacitor being connected to the positive voltage output;
a pull-down module connected to the second terminal of the capacitor for treating the second terminal of the capacitor as a reference voltage before the display driving circuit receives a shutdown signal;
and the pull-up module is connected with the second end of the capacitor and is used for conducting the second end of the capacitor to a first voltage line when the display driving circuit receives a shutdown signal, and the voltage on the first voltage line is greater than the reference voltage.
In one possible implementation manner, the pull-down module and the pull-up module are both connected with a full-on control signal XON of the display driving circuit,
the pull-up module is to treat a second end of the capacitor as a reference voltage when the XON is at an inactive level, the pull-down module to turn on the second end of the capacitor to the first voltage line when the XON is at an active level.
In a possible implementation manner, the pull-down module includes a first switch element, the pull-up module includes a second switch element, and a control end of the first switch element and a control end of the second switch element are both connected to the XON;
a first end of the first switch element is connected with a second end of the capacitor, a second end of the first switch element is connected with a second voltage line, and the voltage on the second voltage line is the reference voltage;
a first end of the second switching element is connected to the first voltage line, and a second end of the second switching element is connected to a second end of the capacitor;
the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of the XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of the XON.
In a possible implementation manner, the voltage output by the positive voltage output terminal is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, and a digital high voltage AVDD output by the power management module; the reference voltage is any one of a logic low voltage VSS, a grid low voltage VGL, an analog low voltage DVSS and a digital low voltage AVSS output by the power management module; the voltage on the first voltage line is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, and a digital high voltage AVDD output by the power management module, and a positive power voltage input to the power management module.
In a second aspect, the present invention also provides a power management device for a display apparatus, the power management device having a positive voltage output terminal, the power management device comprising:
a capacitor, a first end of the capacitor being connected to the positive voltage output;
a pull-down module connected to the second end of the capacitor to handle the second end of the capacitor as a reference voltage before the display device is powered off;
and the pull-up module is connected with the second end of the capacitor and used for conducting the second end of the capacitor to a first voltage line when the display device is powered off, and the voltage on the first voltage line is greater than the reference voltage.
In one possible implementation, the pull-down module and the pull-up module are both connected to a fully-on control signal XON of the display device, the pull-up module is configured to treat the second end of the capacitor as a reference voltage when XON is at an inactive level, and the pull-down module is configured to turn on the second end of the capacitor to the first voltage line when XON is at an active level.
In a possible implementation manner, the pull-down module includes a first switching element, the pull-up module includes a second switching element, and a control terminal of the first switching element and a control terminal of the second switching element are both connected to the XON;
the first end of the first switch element is connected with the second end of the capacitor, the second end of the first switch element is connected with a second voltage line, and the voltage on the second voltage line is the reference voltage;
a first terminal of the second switching element is connected to the first voltage line, and a second terminal of the second switching element is connected to a second terminal of the capacitor;
the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of the XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of the XON.
In a possible implementation manner, the voltage output by the positive voltage output terminal is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD and a digital high voltage AVDD output by the power management device; the reference voltage is any one of logic low voltage VSS, grid low voltage VGL, analog low voltage DVSS and digital low voltage AVSS output by the power management device; the voltage on the first voltage line is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, a digital high voltage AVDD, and a positive power voltage input to the power management module, which are output by the power management device.
In a third aspect, the present invention also provides a display device comprising the display driving circuit of any one of the above, or the power management apparatus of any one of the above.
In a fourth aspect, the present invention also provides a driving method of a display device, the display device including a power management module and a capacitor, the power management module having a positive voltage output terminal, a first terminal of the capacitor being connected to the positive voltage output terminal, the driving method including:
treating a second end of the capacitor as a first reference voltage before the display device is powered off;
when the display device is turned off, conducting a second end of the capacitor to a first voltage line, wherein the voltage on the first voltage line is greater than the first reference voltage.
According to the technical scheme, based on the arrangement of the capacitor and the level control at the second end of the capacitor, the voltage at the positive voltage output end can be instantly raised by utilizing the characteristics of the capacitor when the power-off device is powered off, so that the time for the voltage at the positive voltage output end to be reduced to the minimum allowable voltage can be prolonged, the transistor with the grid connected with the voltage can be rapidly discharged in a short time, the smooth operation of related operations when the power-off device is powered off is facilitated, the abnormal condition caused by the excessively high reduction speed of the voltage when the power-off device is powered off is relieved, the defects of shutdown ghost shadow and the like are favorably eliminated, and the quality and the performance of a product are improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and reasonable variations of the drawings are also covered in the protection scope of the present invention.
Fig. 1 is a block diagram of a display driving circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a display driving circuit according to another embodiment of the present invention;
fig. 3 is a block diagram of a power management device according to another embodiment of the present invention;
fig. 4 is a flowchart illustrating a driving method of a display device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention. Unless defined otherwise, technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and the like, herein does not denote any order, quantity, or importance, but rather the terms "first," "second," and the like are used to distinguish one element from another. The word "comprising" or similar words is intended to mean that the elements or items listed before the word encompass the elements or items listed after the word and their equivalents, without excluding other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, and the connections may be direct or indirect.
Fig. 1 is a block diagram of a display driving circuit according to an embodiment of the present invention. Referring to fig. 1, the display driving circuit includes a power management module 11 and a capacitor C1, wherein the power management module 11 has a positive voltage output terminal 11a, and a first terminal (upper terminal in fig. 1) of the capacitor C1 is connected to the positive voltage output terminal 11 a. In addition, the display driving circuit further includes a pull-down module 12 and a pull-up module 13. The pull-down module 12 and the pull-up module 13 are both connected to the second end (the lower end in fig. 1) of the capacitor C1, the pull-down module 12 is configured to treat the second end of the capacitor C1 as a reference voltage before the display driving circuit receives the shutdown signal, and the pull-up module 13 is configured to conduct the second end of the capacitor C1 to a first voltage line when the display driving circuit receives the shutdown signal, where a voltage on the first voltage line is greater than the reference voltage.
It should be understood that the power management module 11 may have more than one output terminal for outputting high-level voltage, and the positive voltage output terminal 11a may be any one output terminal in an application scenario where an abnormal condition is caused due to an excessively fast decrease speed of the output terminal voltage during shutdown. Of course, for an application scenario where there are a plurality of such output terminals, a set of capacitor, pull-down module, and pull-up module may be respectively disposed corresponding to each of the output terminals according to the solution of the embodiment of the present invention, and the solution may not be limited thereto.
It should also be understood that "shutdown" described herein refers to a process in which the display unit is turned to a non-operating state when the power supply is lost, and the above-described process in which the display driving circuit receives the shutdown signal may be, for example, a process in which the display driving circuit detects that the positive power supply voltage value at the power supply port drops to a shutdown determination threshold (a defined value set for determining whether the power supply port is powered off), may also be, for example, a process in which the display driving circuit receives a shutdown instruction from the outside, and may not be limited thereto.
It should also be understood that, based on the characteristics of the capacitor C1 itself, when the voltage of the second end of the capacitor C1 jumps from the above-mentioned reference voltage to the voltage on the first voltage line, the jumped voltage difference value is also reflected at the first end of the capacitor C1, i.e., the voltage at the positive voltage output terminal 11a jumps upward by the same voltage difference value, i.e., the voltage at the positive voltage output terminal 11a is raised instantaneously at the moment of turning on the second end of the capacitor C1 to the first voltage line.
In one example, the reference voltage is set to 0V, the standard value of the voltage on the first voltage line during normal operation is set to +15V, and the voltage on the first voltage line during shutdown gradually decreases from +15V to about 0V, but the voltage on the first voltage line is always higher than the reference voltage. The standard value of the voltage output by the positive voltage output terminal 11a during normal operation is set to +10V, and the voltage output by the positive voltage output terminal 11a during shutdown gradually decreases from +10V to about 0V. Thus, assuming that the voltage on the first voltage line is +12V at the moment when the pull-up module 13 turns on the second end of the capacitor C1 to the first voltage line, and the voltage output by the positive voltage output terminal 11a is +8V at that moment, since the voltage of the second end of the capacitor C1 jumps from 0V to +12V at that moment, the voltage at the first end of the capacitor C1, that is, the positive voltage output terminal 11a jumps from +8V to +20V based on the characteristics of the capacitor C1 itself.
It is also understood that, after the voltage at the positive voltage output terminal 11a is raised, the source-drain current of the N-type transistors whose gates are connected to this voltage can be increased, thereby accelerating the discharge speed of these N-type transistors, so that the operation depending on the discharge of these N-type transistors can be completed more quickly. Moreover, since the capacitor C1 can function to maintain the potential difference between the first terminal and the second terminal by the stored electric charges, the time during which the voltage at the positive voltage output terminal 11a falls to the minimum allowable voltage after being raised will be extended, so that the operation performed depending on the voltage has an upper limit value capable of a larger processing time.
In one example, the Gate high voltage VGH (Gate voltage for turning on the thin film transistor) output by the power management module 11 to the Gate Driver (Gate Driver) achieves the lift from +13V to +25V at shutdown by the cooperation of the capacitor C1, the pull-down module 12 and the pull-up module 13 through the above process. Therefore, the gate driver can transmit +25V VGH to the N-type transistor in each pixel through the gate line, so that the N-type transistors can rapidly complete the release of residual charges on the pixel electrode of each pixel with larger source-drain current, and the operation of eliminating the residual image during shutdown is completed more rapidly. Moreover, the time for which VGH drops from +25V to +3V, which is the minimum allowable voltage, under the action of the capacitor C1 is significantly longer than the time for which VGH drops from +13V to +3V without the capacitor C1, so that the operation of eliminating the afterimage can have a larger processing time upper limit value, and the residual charge on the pixel electrode of each pixel can be more thoroughly discharged, thereby achieving a better effect of eliminating the afterimage.
Based on the arrangement of the capacitor and the level control performed at the second end of the capacitor, the embodiment of the invention can utilize the characteristics of the capacitor to raise the voltage at the positive voltage output end instantaneously when the power supply is shut down, thereby not only prolonging the time for the voltage at the positive voltage output end to drop to the minimum allowable voltage, but also enabling the transistor with the grid connected with the voltage to discharge rapidly in a short time, being beneficial to smooth operation during the shutdown, relieving abnormal conditions caused by the too fast voltage drop speed during the shutdown, being beneficial to eliminating the defects of shutdown ghost and the like, and improving the quality and the performance of products.
Fig. 2 is a schematic structural diagram of a display driving circuit according to another embodiment of the present invention. Referring to fig. 2, in the display driving circuit of the present embodiment, based on the structure shown in fig. 1, the pull-down module 12 and the pull-up module 13 are both connected to the full-on control signal XON of the display driving circuit. The full-on control signal XON of the display driving circuit is converted from an inactive level to an active level when the display driving circuit is turned off, so as to act on the gate driver to enable all the gate lines to output a signal of the gate high voltage VGH. It should be noted that the active level and the inactive level in this document refer to two different pre-configured voltage ranges (both based on the common terminal voltage) for a specific circuit node, respectively. In one example, the active level of all circuit nodes is a high level in the digital circuit in which they are located. In yet another example, the active levels of all circuit nodes are low levels in the digital circuit in which they are located. Of course, the manner of setting with respect to the active level and the inactive level may not be limited to the above example. In the display driving circuit shown in fig. 2, XON is generated by the power management module 11, that is, for example, it may be a voltage signal output by a corresponding voltage converter in the power management module 11 (in other implementations, XON may also be generated by other circuit parts of the display driving circuit, and may not be limited thereto).
Based on the connection with XON, the pull-down module 12 is further configured to treat the second end of the capacitor C1 as the reference voltage when XON is at the inactive level, and the pull-up module 13 is further configured to turn on the second end of the capacitor C1 to the first voltage line when XON is at the active level. That is, the present embodiment utilizes the characteristic that XON will go from the inactive level to the active level when shutdown, and uses it as a trigger signal for the related operations of the pull-down module 12 and the pull-up module 13, so as to implement the above-mentioned process of raising the voltage at the positive voltage output terminal instantaneously. In other possible implementations, the related operations of the pull-down module 12 and the pull-up module 13 may also be triggered based on signals other than XON, and the trigger signals of the two may be different. For example, the pull-down module 12 may be triggered to stop the operation of setting the second end of the capacitor C1 as the reference voltage by using a voltage signal that momentarily drops below the gate high voltage VGH at shutdown, a circuit module may be provided for detecting the positive power supply voltage input to the power management module 11 to trigger the operation of the pull-up module 13 to turn on the second end of the capacitor C1 to the first voltage line when the positive power supply voltage drops to a shutdown determination threshold, and the present invention is not limited to the above exemplary implementation.
Referring to fig. 2, the pull-down module 12 in this embodiment includes a first switch element, the pull-up module 13 includes a second switch element, and a control terminal of the first switch element and a control terminal of the second switch element are both connected to the fully-on control signal XON. The first end of the first switch element is connected to the second end of the capacitor C1, the second end of the first switch element is connected to a second voltage line, and a voltage on the second voltage line is a common terminal voltage serving as the reference voltage. A first end of the second switching element is connected to a first voltage line, a second end of the second switching element is connected to a second end of the capacitor C1, and a voltage on the first voltage line is a logic high voltage VDD output by the power management module 11. In the setting of the turn-on condition, the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of XON.
In one example, the active level of XON is low, the inactive level of XON is high, the first switching element in the pull-down module 12 shown in fig. 2 is implemented by an N-type thin film transistor, and the second switching element in the pull-up module 13 is implemented by a P-type thin film transistor. Thus, the first switching element may be turned on in a period in which XON is at a high level before the shutdown, and the second end of the capacitor C1 may be set to the reference voltage on the second voltage line by the source-drain current flowing from the second end of the capacitor C1 to the second voltage line; the second switching element may be turned on during a period in which XON is low when the thin film transistor is turned off, and the second terminal of the capacitor C1 may be turned on to the logic high voltage VDD on the first voltage line by using a switching characteristic of the thin film transistor.
Therefore, when the common terminal voltage on the second voltage line as the reference voltage is regarded as 0V of the reference voltage, the capacitor C1, the pull-down module 12 and the pull-up module 13 can change the gate high voltage VGH output by the power management module 11 into the sum of the gate high voltage VGH and the logic high voltage VDD when the power supply is shut down, that is, the voltage at the positive voltage output terminal is raised instantaneously when the power supply is shut down according to the characteristics of the capacitor in the manner described above, so that the embodiment can not only prolong the time for the voltage at the positive voltage output terminal to fall to the minimum allowable voltage, but also can enable the transistor with the gate connected to the voltage to discharge quickly in a short time, thereby facilitating smooth operation during shutdown, alleviating abnormal conditions caused by the excessively fast voltage falling speed during shutdown, facilitating elimination of defects such as shutdown ghost and the like, and improving the quality and performance of the product.
It should be understood that, in the embodiment of the present invention, in addition to the gate high voltage VGH output by the power management module 11, the voltage output by the positive voltage output terminal 11a may be any one of a logic high voltage VDD, an analog high voltage DVDD, and a digital high voltage AVDD output by the power management module 11, for example.
It should also be understood that, in the embodiment of the present invention, in addition to the logic high voltage VDD output by the power management module 11, the voltage on the first voltage line may also be any one of a gate high voltage VGH, an analog high voltage DVDD, and a digital high voltage AVDD output by the power management module 11, and a positive power voltage input to the power management module, for example.
It should also be understood that, in the embodiment of the present invention, the reference voltage may be, for example, any one of a logic low voltage VSS, a gate low voltage VGL, an analog low voltage DVSS, and a digital low voltage AVSS output by the power management module 11, in addition to the common terminal voltage.
Based on the reference voltage and the voltage on the first voltage line set in different manners, the voltage amplitude at which the voltage output by the positive voltage output terminal 11a can be raised when the power supply is turned off may be different, and may be selected according to application requirements when implemented. Of course, the selection of the relevant voltages may not be limited to the above manner.
Fig. 3 is a block diagram of a power management device according to another embodiment of the present invention. Referring to fig. 3, the present embodiment provides a power management apparatus 11 'for a display device, the power management apparatus 11' having a positive voltage output terminal 11', the power management apparatus 11' comprising:
a capacitor C1, wherein a first terminal of the capacitor C1 is connected with the positive voltage output terminal 11' a;
a pull-down module 12 connected to a second terminal of the capacitor C1 for handling the second terminal of the capacitor C1 as a reference voltage before the display device is turned off;
and a pull-up module 13 connected to the second end of the capacitor C1, and configured to conduct the second end of the capacitor C1 to a first voltage line when the display device is turned off, where a voltage on the first voltage line is greater than the reference voltage.
It should be noted that the display device in the embodiment of the present invention may be: the Power Management apparatus in the embodiment of the present invention may be any type of Power Management Module (PMM) in a display device, such as a display panel, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, and so on. On this basis, it should be understood that the above-mentioned before the display apparatus is turned off refers to before the display apparatus or the component having the display function therein is turned into the non-operating state when the power supply is lost, and the above-mentioned when the display apparatus is turned off refers to a period of time during which a process in which the display apparatus or the component having the display function therein is turned into the non-operating state when the power supply is lost is occurring.
In one example, the pull-down module and the pull-up module are both connected to a fully-on control signal XON of the display device, the pull-up module is configured to treat a second end of the capacitor as a reference voltage when XON is at an inactive level, and the pull-down module is configured to turn on the second end of the capacitor to the first voltage line when XON is at an active level.
In one example, the pull-down module comprises a first switching element, the pull-up module comprises a second switching element, and a control terminal of the first switching element and a control terminal of the second switching element are both connected to the XON; a first end of the first switch element is connected with a second end of the capacitor, a second end of the first switch element is connected with a second voltage line, and the voltage on the second voltage line is the reference voltage; a first end of the second switching element is connected to the first voltage line, and a second end of the second switching element is connected to a second end of the capacitor; the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of the XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of the XON.
In one example, the voltage output by the positive voltage output terminal is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD and a digital high voltage AVDD output by the power management device; the reference voltage is any one of a logic low voltage VSS, a grid low voltage VGL, an analog low voltage DVSS and a digital low voltage AVSS output by the power management device; the voltage on the first voltage line is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, a digital high voltage AVDD, and a positive power voltage input to the power management module, which are output by the power management device.
It should be understood that, for the display driving circuit shown in fig. 1, the capacitor C1, the pull-down module 12 and the pull-up module 13 are circuit structures independent of the power management module 11. For the display device in which the power management module 11' shown in fig. 3 is located, the capacitor C1, the pull-down module 12 and the pull-up module 13 are circuit structures integrated inside the power management module. Therefore, the power management apparatus 11' of the present embodiment can be implemented with reference to any one of the implementations of the display driving circuit described above, and is not limited thereto. It should also be understood that in addition to the implementation of the display Driver circuit shown in fig. 1, the capacitor C1, the pull-down module 12, and the pull-up module 13 may be disposed among components within the display Driver circuit in any component distribution manner, for example, the capacitor and the pull-up module may be disposed in a power management module, and the pull-down module may be disposed in a Gate Driver (Gate Driver); or the capacitor, the pull-down module and the pull-up module are all arranged in a Timing Controller (TCON). Of course, the arrangement positions of the capacitor C1, the pull-down module 12, and the pull-up module 13 may not be limited to the above manner.
Based on the same inventive concept, still another embodiment of the present invention provides a display apparatus including the display driving circuit of any one of the above or the power management device of any one of the above. The display device in the embodiment of the present invention may be: any product or component with a display function, such as a display panel, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like. Based on the beneficial effects obtained by the display driving circuit or the power management device, the display equipment can also obtain the same or corresponding beneficial effects.
Fig. 4 is a flowchart illustrating a driving method of a display device according to an embodiment of the present invention. In this embodiment, the display device includes a power management module and a capacitor, where the power management module has a positive voltage output terminal, and a first terminal of the capacitor is connected to the positive voltage output terminal. Referring to fig. 4, the driving method of the present embodiment includes:
It should be understood that the working process of any one of the display driving circuits or the power management apparatus can be regarded as an example of an implementation manner of the driving method, and therefore, specific process examples of the steps can be referred to above, and are not described herein again.
Based on the arrangement of the capacitor and the level control performed at the second end of the capacitor, the embodiment of the invention can utilize the characteristics of the capacitor to raise the voltage at the positive voltage output end instantaneously when the power supply is shut down, thereby not only prolonging the time for the voltage at the positive voltage output end to drop to the minimum allowable voltage, but also enabling the transistor with the grid connected with the voltage to discharge rapidly in a short time, being beneficial to smooth operation during the shutdown, relieving abnormal conditions caused by the too fast voltage drop speed during the shutdown, being beneficial to eliminating the defects of shutdown ghost and the like, and improving the quality and the performance of products.
In addition, for any of the above Power Management modules or Power Management devices, a Power Management chip (PMIC) may be included inside the PMIC, and a voltage converter such as a Low Dropout Regulator (LDO) may be included inside the PMIC to obtain a required portion of voltage or signal (e.g., a logic high voltage VDD, an analog high voltage DVDD, an on/off control signal XON, etc.) based on the input Power voltage; furthermore, the power management chip may be provided with, for example, a charge pump (charge pump) outside the power management chip, so that another required voltage or signal (for example, a gate high voltage VGH or the like) is realized by an external circuit structure.
The above description is only exemplary of the present invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A display driver circuit comprising a power management module having a positive voltage output, the display driver circuit further comprising:
a capacitor, a first end of the capacitor being connected to the positive voltage output;
a pull-down module connected to the second terminal of the capacitor for handling the second terminal of the capacitor as a reference voltage before the display driving circuit receives a shutdown signal;
the pull-up module is connected with the second end of the capacitor and used for conducting the second end of the capacitor to a first voltage line when the display driving circuit receives a shutdown signal, and the voltage on the first voltage line is greater than the reference voltage;
wherein the pull-down module and the pull-up module are both connected to a fully-on control signal XON of the display driving circuit, the XON being a signal that changes from an inactive level to an active level when turned off, the pull-up module being configured to treat a second end of the capacitor as a reference voltage when the XON is an inactive level, the pull-down module being configured to turn on the second end of the capacitor to the first voltage line when the XON is an active level; the pull-down module comprises a first switch element, the pull-up module comprises a second switch element, and a control end of the first switch element and a control end of the second switch element are both connected with the XON;
a first end of the first switch element is connected with a second end of the capacitor, a second end of the first switch element is connected with a second voltage line, and the voltage on the second voltage line is the reference voltage;
a first end of the second switching element is connected to the first voltage line, and a second end of the second switching element is connected to a second end of the capacitor;
the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of the XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of the XON.
2. The display driving circuit according to claim 1, wherein the voltage outputted by the positive voltage output terminal is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, and a digital high voltage AVDD outputted by the power management module; the reference voltage is any one of logic low voltage VSS, grid low voltage VGL, analog low voltage DVSS and digital low voltage AVSS output by the power management module; the voltage on the first voltage line is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, and a digital high voltage AVDD output by the power management module, and a positive power voltage input to the power management module.
3. A power management device for a display device, the power management device having a positive voltage output, the power management device comprising:
a capacitor, a first end of the capacitor being connected to the positive voltage output;
a pull-down module connected to the second end of the capacitor to handle the second end of the capacitor as a reference voltage before the display device is powered off;
a pull-up module connected to a second end of the capacitor, for conducting the second end of the capacitor to a first voltage line when the display device is turned off, a voltage on the first voltage line being greater than the reference voltage;
the pull-down module and the pull-up module are both connected to a fully-on control signal XON of the display device, the XON is a signal converted from an inactive level to an active level when the display device is turned off, the pull-up module is configured to treat a second end of the capacitor as a reference voltage when the XON is at the inactive level, and the pull-down module is configured to turn on the second end of the capacitor to the first voltage line when the XON is at the active level; the pull-down module comprises a first switch element, the pull-up module comprises a second switch element, and a control end of the first switch element and a control end of the second switch element are both connected with the XON;
a first end of the first switch element is connected with a second end of the capacitor, a second end of the first switch element is connected with a second voltage line, and the voltage on the second voltage line is the reference voltage;
a first end of the second switching element is connected to the first voltage line, and a second end of the second switching element is connected to a second end of the capacitor;
the first switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an inactive level of the XON, and the second switching element is configured to conduct between the first terminal and the second terminal when the control terminal is at an active level of the XON.
4. The power management device according to claim 3, wherein the voltage outputted by the positive voltage output terminal is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD and a digital high voltage AVDD outputted by the power management device; the reference voltage is any one of logic low voltage VSS, grid low voltage VGL, analog low voltage DVSS and digital low voltage AVSS output by the power management device; the voltage on the first voltage line is any one of a logic high voltage VDD, a gate high voltage VGH, an analog high voltage DVDD, a digital high voltage AVDD, and a positive power voltage input to the power management device, which are output by the power management device.
5. A display device comprising a display driver circuit as claimed in claim 1 or 2, or a power management apparatus as claimed in any one of claims 3 or 4.
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| CN201710890449.3A CN107610632B (en) | 2017-09-27 | 2017-09-27 | Display driving circuit, power management device, display apparatus and driving method thereof |
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| CN201710890449.3A CN107610632B (en) | 2017-09-27 | 2017-09-27 | Display driving circuit, power management device, display apparatus and driving method thereof |
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| CN110838272B (en) * | 2018-08-15 | 2021-07-09 | 合肥捷达微电子有限公司 | Power supply detection circuit and liquid crystal display device |
| CN109036322B (en) * | 2018-09-26 | 2023-11-03 | 北京集创北方科技股份有限公司 | Input buffer, control method, driving device and display device |
| CN109326258B (en) * | 2018-11-21 | 2021-11-12 | 合肥鑫晟光电科技有限公司 | Shift register unit and display panel |
| CN110289841A (en) * | 2019-07-03 | 2019-09-27 | 苏州源特半导体科技有限公司 | A kind of ladder driving circuit |
| CN110516607B (en) * | 2019-08-28 | 2022-08-05 | 京东方科技集团股份有限公司 | Fingerprint identification structure, fingerprint identification display device and driving method |
| JP7371455B2 (en) * | 2019-11-21 | 2023-10-31 | セイコーエプソン株式会社 | Drive circuit, display module, and moving object |
| JP2021117303A (en) * | 2020-01-23 | 2021-08-10 | シャープ株式会社 | Control device, control method, and display device |
| CN113707071B (en) * | 2021-08-31 | 2024-01-12 | Tcl华星光电技术有限公司 | Reference voltage generating circuit and display device |
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