Patent Application
20210027690
The present disclosure claims the priority to Chinese Patent Application No. 201811342325.2, filed Nov. 12, 2018 with the National Intellectual Property Administration and entitled “CONTROL CIRCUIT, DISPLAY APPARATUS, AND CONTROL METHOD FOR CONTROL CIRCUIT”, the entirety of which is hereby incorporated herein by reference.
The present disclosure relates to the field of display technology, and more particularly relates to a control circuit, a display apparatus, and a control method for a control circuit.
Charge stored in a display panel is discharged when the display apparatus is turned off. The bigger the size of the display apparatus is, the longer the time duration required for the electric discharge. A longer time duration for the electric discharge brings about a more obvious persistence of image on the display panel. To avoid the persistence of image, the charge stored in the display panel needs to be discharged more rapidly when the display apparatus is turned off.
In the display apparatus, a power supply chip receives an input voltage of 12V. In turn, the power supply chip outputs a main voltage VAA to a source driver and a gamma correction circuit, outputs a digital logic voltage VDD to the source driver circuit, the gamma correction circuit and a timing control circuit, and outputs a turn-on voltage VGH and a turn-off voltage VGL to a gate driver.
When the display is turned off, the 12V voltage input to the power supply chip drops down to a low voltage protection level of the power supply chip, making the power supply chip out of operation. At the same time, the VAA, VDD, VGH, and VGL are powered down, among which the VDD is discharged fastest, while the VAA and VGH are discharged slowest.
It is found that how soon the VAA discharges has a great influence on the persistence of image. The faster the VAA is discharged, the less obvious the persistence of image is. To restrain the persistence of image, a ground resistance may be arranged at each power supply node in the power supply circuit to accelerate the electric discharge of the charge in the display panel. The smaller the resistance is, the faster the electric discharge rate is. However, the ground resistance would increase power consumption of the whole system.
The present disclosure is to provide a control circuit, a display apparatus, and a control method for the control circuit, aiming to reduce the persistence of image when the display apparatus is turned off.
In one aspect, the present disclosure provides a control circuit, including:
In another aspect, the present disclosure provides a display apparatus, including: a display panel, a circuit board and a control circuit, the circuit board is connected with the display panel, the control circuit is arranged on the circuit board; and the control circuit includes:
In still another aspect, the present disclosure provides a control method for a control circuit, the control circuit including a first power input end and a second power input end that are connected to a power supply, a voltage control circuit, a voltage detection circuit, a switch circuit, and a discharging circuit; where the control method includes:
In the present disclosure, the voltage control circuit generates the reference voltage signal, and then outputs the reference voltage signal to the first input end of the voltage detection circuit. The voltage signal output by the second power input end is input to the second input end of the voltage detection circuit. The voltage detection circuit outputs the corresponding voltage detection signal to the switch circuit, so as to control the switch circuit to be on or off. Since the switch circuit is connected in series with the discharging circuit, the discharging circuit is allowed to implement electric discharge when the switch circuit is on, so as to reduce the persistence of image. In addition, the discharging circuit would not implement electric discharge when the switch circuit is off, so as to reduce the system power consumption.
In order to illustrate the technical solution in the embodiments of the present disclosure or the prior art more clearly, brief description would be made below to the drawings required in the embodiments of the present disclosure or the prior art. Obviously, the drawings in the following description are merely some of the embodiments of the present disclosure, and those skilled in the art could obtain other drawings according to the structures shown in the drawings without any creative efforts.
The realizing of the aim, functional characteristics and advantages of the present disclosure are further described in detail with reference to the accompanying drawings and the embodiments.
The technical solutions in the embodiments of the present disclosure will be described clearly and completely combining the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all of them. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work shall belong to the protection scope of the present disclosure.
It should be understand that, all directional indications (such as “upper”, “lower”, “left”, “right”, “front”, “back” . . . ) in the embodiments of the present disclosure are only used to explain the relative positional relationship, motion, and the like, between components in a certain posture. If the particular posture changes, the directional indication changes accordingly.
In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or to imply the number of indicated technical features. Thus, the features defined with “first” and “second” may comprise or imply at least one of these features. In the description of the present disclosure, “a plurality of” means two or more than two, unless specified otherwise.
In order to reduce the persistence of vision when the display apparatus is turned off, the control circuit according to the present disclosure may be integrated in the source driver, or be integrated in the gamma correction circuit P-Gamma IC. By integrating the control circuit according to the present disclosure in the source driver and/or the gamma correction circuit P-Gamma IC, the persistence of vision can be effectively reduced when the display apparatus is turned off.
Referring to
In this embodiment, the voltage control circuit 10 outputs a corresponding reference voltage signal to the voltage detection circuit 20 according to a received voltage signal input by the first power input end. The voltage control circuit 10 may be a voltage regulator, or other kinds of circuits known in the related art, which is not limited herein.
In this embodiment, the voltage detection circuit 20 outputs a corresponding voltage detection signal to the switch circuit 30 when the received voltage signal input by the second power input end drops down to the reference voltage signal, so as to control the switch circuit 30 to be on. The voltage detection circuit 20 may be a circuit of sampling resistor voltage dividing detection, voltage comparator or Hall sensor and so on, which is not limited herein.
In this embodiment, the switch circuit 30 has ON and OFF states, which may be realized by using various transistor components, such as an insulated field effect transistor, a triode, and a composite switch circuit composed of a plurality of transistors, which is not limited herein.
In this embodiment, the discharging circuit 40 is configured to discharge when the switch circuit 30 is on. The discharging circuit 40 may be a resistor, a diode, or a combined discharging circuit of a resistor and a diode.
As an example, the control circuit integrated within the source driving circuit is described. In the present disclosure, the voltage control circuit 10 generates the corresponding reference voltage signal according to the received main voltage VAA input by the first power input end. In practice, the main voltage VAA needs to be boosted and then input to the source driving circuit. The voltage input to the source driving circuit may be 15V to 18V. The reference voltage signal is input to the first input end of the voltage detection circuit 20, and the digital logic voltage VDD input by the second power input end is input to the second input end of the voltage detection circuit 20. The digital logic voltage VDD may be 3.3V, and may also be determined according to actual needs. When the display apparatus is turned off, the main voltage VAA input by the first power input end and the digital logic voltage VDD input by the second power input end start to drop down. When the digital logic voltage VDD drops below the reference voltage signal, the voltage detection circuit 20 outputs a corresponding voltage detection signal, such as a high-level voltage detection signal, to the switch circuit 30 to control the switch circuit 30 to be on. The switch circuit 30 is connected in series with the discharging circuit 40, thus, the discharging circuit 40 and the first power input end are in a closed-circuit state, when the switch circuit 30 is on. In this case, the main voltage VAA is rapidly discharged through the discharging circuit 40. When the display apparatus is in normal operation, since the reference voltage signal input to the voltage detection circuit 20 is smaller than the digital logic voltage VDD, the switch circuit 30 is off, and accordingly the discharging circuit 40 and the first power input end are in an open-circuit state. In this case, the main voltage VAA cannot be discharged through the discharging circuit 40. By this way, the persistence of image can be effectively reduced, and also the power consumption of the system can be avoided from increasing.
In an embodiment, referring to
Specifically, the voltage control circuit 10 receives the voltage signal input by the first power input end, namely a main voltage VAA, and outputs the corresponding reference voltage signal to the voltage detection circuit 20. The voltage control circuit 10 outputs the fixed reference voltage signal to the voltage detection circuit 20 before the main voltage VAA input by the first power input end is larger than a stabilizing voltage of the Zener diode D1. In practice, the voltage signal input by the second power input end, namely a digital logic voltage VDD, may be 3.3V, and the magnitude of the reference voltage signal may be determined according to the stabilizing voltage of the selected Zener diode D1. The stabilizing voltage of the Zener diode D1 may be 3/5 to 4/5 of the digital logic voltage VDD, or lower than the digital logic voltage VDD, such as a 2.7V. The stabilizing voltage of the Zener diode cannot be too low to ensure that there is plenty of time for the main voltage VAA to be discharged through the discharging circuit 40 when the display apparatus is turned off. And by arranging the first resistor R1 between the Zener diode D1 and the first power input end, it can prevent the Zener diode D1 from stabilizing the main voltage VAA to the stabilizing voltage of the Zener diode D1.
In an embodiment, referring to
Specifically, the non-inverting input end of the voltage comparator U1 receives the reference voltage signal output by the voltage control circuit 10, and the inverting input end of the voltage comparator U1 receives the digital logic voltage VDD output by the second power input end. The voltage comparator U1 outputs a high level if the voltage input to the non-inverting input end is greater than the voltage input to the inverting input end, otherwise the voltage comparator U1 outputs a low level. When the display apparatus is in normal operation, the digital logic voltage VDD is higher than the reference voltage signal. At this time, the voltage comparator U1 outputs a low-level voltage detection signal which acts on the switch circuit 30 to turn off the switch circuit 30. When the display apparatus is turned off, the digital logic voltage VDD starts to drop, and when the digital logic voltage drops below the reference voltage signal, the voltage comparator U1 outputs a high-level voltage detection signal, so as to control the switch circuit 30 to be on. Therefore, the voltage detection signal output from the voltage detection circuit 20 can be used to control the switch circuit to be on or off.
In an embodiment, referring to
Specifically, when the display apparatus is in normal operation, the digital logic voltage VDD input to the voltage detection circuit 20 is greater than the reference voltage signal, and the voltage detection circuit 20 outputs the low-level voltage detection signal to the gate of the N-MOS transistor, so as to control N-MOS transistor to be off. Since the discharging circuit 40 is connected in series with the switch circuit 30, at this time, the discharging circuit 40 and the first power input end are in the open-circuit state. When the display apparatus is turned off, the digital logic voltage VDD starts to drop. And when the digital logic voltage VDD is lower than the reference voltage signal, the voltage detection circuit 20 outputs the high-level voltage detection signal to the gate of the N-MOS transistor, so as to control the N-MOS transistor to be on. At this time, the first power input end and the discharging circuit 40 are in the closed-circuit state. By controlling the switch circuit 30 to be on and off, it is possible to control that whether the discharging circuit 40 is connected to the first power input end to be discharged.
In an embodiment, referring to
Specifically, the second resistor R2 is connected in series with the switch circuit 30. The switch circuit 30 is off when the display apparatus is in normal operation. At this time, the second resistor R2 is in open-circuit connection with the first power input end, and no current flows through the second resistor R2. Therefore, when the display apparatus is in normal operation, the second resistor R2 does not discharge, which would not increase power consumption in the system. And the switch circuit 30 is switched to the on state from the off state when the display apparatus is turned off. At this time, the second resistor R2 is closed-circuit connection with the first power input end, and the main voltage VAA can be discharged through the second resistor R2. By this way, the persistence of vision can be effectively reduced, also an increase in the system power consumption due to addition of the control circuit can be avoided.
The present disclosure also provides a display apparatus. The display apparatus includes a display panel, a circuit board and a control circuit as described above. The circuit board is connected to the display panel, and the control circuit is arranged on the circuit board. The specific structure of the control circuit can be referred to the above embodiments, which are not detailed herein. It can be understood that, since the display apparatus according to the present disclosure includes the above control circuit, the embodiments thereof include all the technical solutions of all the embodiments of the control circuit, and identical technical effects can also be achieved, thus are not detailed herein.
In this embodiment, the display apparatus may be one that includes a display panel, such as a television, a tablet, or a mobile phone.
The present disclosure also provides a control method of the control circuit. Referring to
Optionally, step S2 includes:
The structure of the control circuit is as shown in
Specifically, the main voltage VAA input by the first power input end is regulated by the Zener diode D1 after being through the first resistor R1, so as to obtain the reference voltage signal. The reference voltage signal is output to the non-inverting input end of the voltage comparator U1, and the digital logic voltage VDD input by the second power input end is output to the inverting input end of the voltage comparator U1. When the display apparatus is in normal operation, the digital logic voltage VDD is greater than the reference voltage signal, and the voltage comparator U1 outputs a low-level voltage detection signal to the gate of the N-MOS transistor, at which time the N-MOS transistor is turned off, and no current flows through the second resistor R2. Current flows through. When the display apparatus is turned off, the main voltage VAA and the digital logic voltage VDD start to decrease. Since the digital logic voltage VDD drops faster than the main voltage VAA, when the digital logic voltage VDD drops below the reference voltage signal, the voltage comparator U1 outputs a high-level voltage detection signal to the gate of the N-MOS transistor, at which time the N-MOS transistor is turned on, and the main voltage VAA is discharged through the second resistor R2. In the present disclosure, speeding up the discharge of the main voltage VAA reduces the persistence of vision effectively.
The foregoing are only illustrative embodiments in accordance with the present disclosure and therefore not intended to limit the patentable scope of the present disclosure. Any equivalent structure or flow transformations that are made taking advantage of the specification and accompanying drawings of the disclosure and any direct or indirect applications thereof in other related technical fields are within the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811342325.2 | Nov 2018 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2018/122163 | 12/19/2018 | WO | 00 |
