A driving control device and method for preventing polarization of IPS display screen

Abstract

The present invention relates to the technical field of display screen control, and in particular to a driving control device for preventing polarization of an IPS display screen. The device comprises a main control MCU, a liquid crystal voltage control circuit, a liquid crystal voltage detection circuit and an RGB control signal detection circuit. Each power supply voltage of a liquid crystal is independently controlled, and a power-on and power-off timing sequence can be controlled strictly according to a timing requirement of the main control MCU, so as to prevent polarization of the liquid crystal caused by a power-on and power-off timing error. The main control MCU monitors whether the power supply voltage of the liquid crystal is abnormal in real time. If any voltage is abnormal, other control signal outputs are immediately turned off, and the liquid crystal power supply voltage output is cut off. The main control MCU monitors the RGB control signal output in real time. Once an abnormality occurs in the RGB control signal, the main control MCU can quickly turn off the RGB signal output, and turn off the liquid crystal power supply voltage output according to the power-off timing sequence, so as to prevent polarization of the liquid crystal.

Description

Technical Field

[0001] The invention relates to the technical field of display screen control, in particular to a driving control device for preventing an IPS display screen from polarizing. Background Art

[0002] At present, the consumer market's requirements for display effects are constantly increasing, and IPS displays have excellent color performance and a wide viewing angle. Furthermore, with the advancement of technology and the improvement of production processes, the cost of IPS displays has gradually decreased, making it more competitive in price and can be widely used in various electronic devices.

[0003] However, IPS display screens have high requirements for power-on timing, power-off timing, LCD controller and power supply voltage. If the power-on and power-off timing does not meet the requirements of the driver IC, the control signal is abnormal, or the liquid crystal power supply voltage is abnormal, it is easy to cause liquid crystal polarization. At present, the driving control circuit of IPS display screens is that after the system is powered on, the liquid crystal power supply voltage is powered on synchronously, and there is no power-on and power-off timing control between the various power supply voltages of the liquid crystal. After the system is shut down, the liquid crystal power supply voltage is not turned off. When the output signal of the LCD controller is abnormal, the liquid crystal power supply voltage cannot be turned off, which causes the liquid crystal to polarize under long-term stress. Summary of the invention

[0004] The present invention aims to solve the problems in the prior art and provides a driving control device for preventing polarization of an IPS display screen. The driving control device can control the power-on timing and the power-off timing of the IPS display screen and can timely shut down the working voltage and RGB control signal of the IPS display screen, thereby avoiding polarization of liquid crystal.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions on one hand: a driving control device for preventing polarization of an IPS display screen, comprising a main control MCU, a liquid crystal voltage control circuit, a liquid crystal voltage detection circuit and an RGB control signal detection circuit;

[0006] After the external power supply provides power to the liquid crystal voltage control circuit, the main control MCU controls the liquid crystal voltage control circuit to provide four working voltages for the IPS display screen in a time sequence; the liquid crystal voltage detection circuit detects the four working voltages of the IPS display screen in real time, and transmits the detection data to the main control MCU, and the main control MCU determines whether the working voltage of the IPS display screen is abnormal according to the detection data. If an abnormality occurs, the main control MCU cuts off the working voltage of all IPS display screens and stops providing RGB control signals to the IPS display screen; the RGB control signal detection circuit is used to detect the RGB control signal provided to the IPS display screen, and transmits the detection data to the main control MCU. If an abnormality occurs in the detection result, the main control MCU shuts off the output of the RGB data signal and the RGB control signal, and cuts off the output of the liquid crystal voltage control circuit.

[0007] Preferably, the liquid crystal voltage control circuit includes a voltage supply module and a timing control module, and the voltage supply module includes a first voltage supply unit, a second voltage supply unit, a third voltage supply unit and a fourth voltage supply unit; the output ends of the first voltage supply unit, the second voltage supply unit, the third voltage supply unit and the fourth voltage supply unit are all connected to the input end of the timing control module, the main control MCU is connected to the control end of the timing control module, and the output end of the timing control module is connected to the IPS display screen;

[0008] When the IPS display screen is powered on, the main control MCU sequentially provides the fourth voltage, the first voltage, the second voltage and the third voltage to the IPS display screen through the timing control module; when the IPS display screen is powered off, the main control MCU controls the timing control module to sequentially power off the third voltage, the second voltage, the first voltage and the fourth voltage, and before powering off, the main control MCU stops providing RGB control signals and RGB data signals to the IPS display screen.

[0009] Preferably, the first voltage providing unit includes a voltage input unit, a booster U1, a diode D2, a feedback unit and a first filtering unit, the external power supply is connected to the input end of the booster U1 through the voltage input unit, the output end of the booster U1 provides the first voltage after passing through the diode D2, the feedback unit is used to feed back the first voltage to the booster U1, and the first filtering unit is used to filter the first voltage;

[0010] The second voltage providing unit includes a switching diode D4, a capacitor C9, a resistor R10, a diode D5 and a second filtering unit. The output end of the booster U1 is connected to the input end of the switching diode D4 through the capacitor C9, one output end of the switching diode D4 outputs the second voltage after passing through the resistor R10, and the other output end of the switching diode D4 is grounded. The second filtering unit is used to filter the second voltage, and the second voltage is grounded through the diode D5; the third voltage providing unit includes a switching diode D1, a capacitor C1, a resistor R1, a diode D3 and a third filtering unit. The output end of the booster U1 is connected to the input end of the switching diode D1 through the capacitor C1, one output end of the switching diode D1 outputs the third voltage through the resistor R1, and the other output end of the switching diode D1 is connected to the first voltage. The third filtering unit is used to filter the third voltage, and the third voltage is grounded through the diode D3; the fourth voltage providing unit includes a voltage regulator U3, the input end of the voltage regulator U3 is connected to the external power supply, the enable end of the voltage regulator U3 is connected to the main control MCU, and the output end of the voltage regulator U3 outputs the fourth voltage.

[0011] Preferably, the timing control module includes a first voltage switch control unit, a second voltage switch control unit and a third voltage switch control unit;

[0012] The first voltage switch control unit includes a switch tube Q3, a switch tube Q6, a resistor R32 and a resistor R29, the main control MCU is connected to the control end of the switch tube Q6 through the resistor R32, one switch end of the switch tube Q6 is grounded, the other switch end of the switch tube Q6 is connected to the control end of the switch tube Q3 through the resistor R29, one switch end of the switch tube Q3 is connected to the first voltage, and the other switch end of the switch tube Q3 is connected to the IPS display screen; the third voltage switch control unit includes a switch tube Q2, a switch tube Q5, a resistor R31 and a resistor R28, the main control MCU is connected to the control end of the switch tube Q5 through the resistor R31, one switch end of the switch tube Q5 is grounded, the other switch end of the switch tube Q5 is connected to the control end of the switch tube Q2 through the resistor R28, and one switch end of the switch tube Q2 The second voltage switch control unit includes a switch tube Q1, a switch tube Q4, a switch tube Q7, a resistor R33, a resistor R30, a resistor R34 and a resistor R35. The main control MCU is connected to the control end of the switch tube Q7 through the resistor R33. One switch end of the switch tube Q7 is grounded. The other switch end of the switch tube Q7 is connected to the control end of the switch tube Q4 through the resistor R30. One switch end of the switch tube Q4 is connected to the external power supply through the resistor R35. The control end of the switch tube Q4 is connected to the external power supply through the resistor R34. The other switch end of the switch tube Q4 is connected to the control end of the switch tube Q1. One switch end of the switch tube Q1 is connected to the second voltage, and the other switch end of the switch tube Q1 is connected to the IPS display.

[0013] Preferably, the liquid crystal voltage detection circuit includes a first voltage detection unit, a second voltage detection unit, a third voltage detection unit and a fourth voltage detection unit;

[0014] The first voltage detection unit includes a resistor R6 and a resistor R13, the first voltage is connected to the main control MCU through the resistor R6, and one end of the resistor R6 connected to the main control MCU is grounded through the resistor R13; the third voltage detection unit includes a resistor R7 and a resistor R14, the third voltage is connected to the main control MCU through the resistor R7, and one end of the resistor R7 connected to the main control MCU is grounded through the resistor R14; the fourth voltage detection unit includes a resistor R5 and a resistor R12, the fourth voltage is connected to the main control MCU through the resistor R5, and one end of the resistor R5 connected to the main control MCU is grounded through the resistor R12; the second voltage detection unit includes an amplifier, a resistor R21, a resistor R23, a resistor R20 and a resistor R22, one input end of the amplifier is connected to an external power supply, the second voltage is connected to the other input end of the amplifier through the resistor R23, and the other input end of the amplifier is also connected to a reference voltage Vref through the resistor R21, the output end of the amplifier is connected to the main control MCU through the resistor R20, and one end of the resistor R20 connected to the main control MCU is grounded through the resistor R22.

[0015] Preferably, the RGB control signal detection circuit includes a signal amplification module and a signal shaping module, the output end of the signal amplification module is connected to the input end of the signal shaping module, the RGB control signal output by the main control MCU to the IPS display screen is input to the main control MCU after the signal amplification effect of the signal amplification module and the signal shaping effect of the signal shaping module, and the main control MCU determines whether the RGB control signal of the IPS display screen is abnormal according to the received shaped signal. When an abnormality occurs, the main control MCU shuts off the output of the RGB data signal and the RGB control signal, and cuts off the supply of the working voltage of the IPS display screen.

[0016] A second aspect of the present invention discloses a driving control method for preventing polarization of an IPS display screen, comprising the following method:

[0017] The external power supply starts supplying power, and generates a first voltage, a second voltage, a third voltage, and a fourth voltage through the liquid crystal voltage control circuit;

[0018] The main control MCU sequentially provides the fourth voltage, the first voltage, the second voltage and the third voltage to the IPS display screen through the timing control module;

[0019] The main control MCU opens the ADC detection channel and detects in real time through the liquid crystal voltage detection circuit whether the first voltage, the second voltage, the third voltage and the fourth voltage are abnormal; if the voltage detection is abnormal, the main control MCU shuts off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage; if the voltage detection is normal, the main control MCU provides RGB data signals and RGB control signals for the IPS display screen;

[0020] The main control MCU sets a timer and regularly detects the RGB control signal through the RGB control signal detection circuit; if the detection is normal, the display of the IPS display screen is turned on and the backlight of the IPS display screen is turned on, and the IPS display screen starts to display normally; if the detection is abnormal, the main control MCU first turns off the output of the RGB data signal and the RGB control signal, and then turns off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage. Beneficial effects of the present invention:

[0021] 1. Each power supply voltage of the liquid crystal is independently controlled, and the power-on and power-off timing can be strictly controlled according to the timing requirements of the main control MCU to prevent the polarization of the liquid crystal caused by the power-on and power-off timing errors;

[0022] 2. The main control MCU monitors the LCD power supply voltage in real time to see if it is abnormal. If any voltage abnormality occurs, it will immediately shut down other control signal outputs and cut off the LCD power supply voltage output;

[0023] 3. The main control MCU monitors the RGB control signal output in real time. Once the RGB control signal is abnormal, the main control MCU can quickly shut down the RGB signal output and shut down the LCD power supply voltage output according to the power-off sequence to prevent the LCD from polarization;

[0024] 4. The driving control circuit has flexible control and comprehensive monitoring, which effectively avoids the liquid crystal polarization phenomenon caused by abnormal signals or voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a signal block diagram of the present invention;

[0026] Figure 2 It is a signal block diagram of the liquid crystal voltage control circuit of the present invention;

[0027] Figure 3 It is a power-on timing diagram of the present invention;

[0028] Figure 4 This is a power-off timing diagram of the present invention;

[0029] Figure 5 It is a signal block diagram of the liquid crystal voltage detection circuit of the present invention;

[0030] Figure 6 It is a signal block diagram of the RGB control signal detection circuit of the present invention;

[0031] Figure 7 A circuit schematic diagram of a first voltage providing unit of the present invention;

[0032] Figure 8 A circuit schematic diagram of a second voltage providing unit of the present invention;

[0033] Fig. 9 A circuit schematic diagram of a third voltage providing unit of the present invention;

[0034] Fig.10 A circuit schematic diagram of a fourth voltage providing unit of the present invention;

[0035] Fig.11 is a circuit schematic diagram of a first voltage switch control unit of the present invention;

[0036] Fig.12 is a circuit schematic diagram of a second voltage switch control unit of the present invention;

[0037] Fig.13 is a circuit schematic diagram of a third voltage switch control unit of the present invention;

[0038] Fig.14 is a circuit schematic diagram of a first voltage detection unit of the present invention;

[0039] Fig.15 is a circuit schematic diagram of a third voltage detection unit of the present invention;

[0040] Fig.16 is a circuit schematic diagram of a fourth voltage detection unit of the present invention;

[0041] Fig.17 is a circuit schematic diagram of a second voltage detection unit of the present invention;

[0042] Fig.18 It is a circuit principle diagram of the RGB control signal detection circuit of the present invention;

[0043] Fig.19 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings, and the contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0045] Embodiment 1:

[0046] This embodiment provides a driving control device for preventing polarization of an IPS display screen, such as Figures 1 to 18 , including a main control MCU, a liquid crystal voltage control circuit, a liquid crystal voltage detection circuit and an RGB control signal detection circuit;

[0047] After the external power supply provides power to the liquid crystal voltage control circuit, the main control MCU controls the liquid crystal voltage control circuit to provide four working voltages for the IPS display screen in a time sequence;

[0048] The liquid crystal voltage detection circuit detects the four working voltages of the IPS display screen in real time, and transmits the detection data to the main control MCU. The main control MCU determines whether the working voltage of the IPS display screen is abnormal according to the detection data. If an abnormality occurs, the main control MCU cuts off the working voltage of all IPS display screens and stops providing RGB control signals to the IPS display screen;

[0049] The RGB control signal detection circuit is used to detect the RGB control signal provided to the IPS display screen and transmit the detection data to the main control MCU. If the detection result is abnormal, the main control MCU shuts down the output of the RGB data signal and the RGB control signal, and cuts off the output of the liquid crystal voltage control circuit.

[0050] Specifically, if Figure 1 As shown, the main control MCU is a controller of the prior art, which has a built-in LCD controller and a timer, etc. In this embodiment, the power-on timing and power-off timing of the IPS display are controlled by the main control MCU, and each power supply voltage of the liquid crystal is independently controlled. The power-on and power-off timing can be controlled strictly according to the timing requirements of the main control MCU to prevent the polarization of the liquid crystal caused by the power-on and power-off timing errors.

[0051] More specifically, the connection between the main control MCU and the liquid crystal voltage control circuit, the liquid crystal voltage detection circuit and the RGB control signal is as follows: Figures 1 to 6 As shown, when working, the liquid crystal voltage control circuit is first powered by an external power supply, and the liquid crystal voltage control circuit generates four voltages, namely the first voltage (AVDD), the second voltage (VGL), the third voltage (VGH) and the fourth voltage (VDD). When powered on, the main control MCU controls the IPS display screen to provide the fourth voltage, the first voltage, the second voltage and the third voltage in sequence through the timing control module. After powering on, the liquid crystal detection module is used to detect whether the four voltages are abnormal in real time. When an abnormality occurs, the main control MCU promptly cuts off the power supply of the IPS display screen through the timing control module, and the power-off timing is the third voltage, the second voltage, the first voltage and the fourth voltage. If the detection voltage is normal, the main control MCU starts to provide RGB control signals and RGB data signals to the IPS display screen through the LCD controller, and the RGB control signal detection circuit regularly detects whether the RGB control signal and the RGB data signal are normal. If normal, the main control MCU controls the IPS display screen to start displaying. If the detection signal is abnormal, the main control MCU promptly cuts off the provision of the RGB control signal and the RGB data signal, and disconnects the power supply voltage of the IPS display screen according to the power-off timing. Therefore, this embodiment can detect the power supply voltage and current signal of the liquid crystal in real time, and monitor the power supply of the liquid crystal and the output signal of the LCD controller. When the signal is abnormal, the power supply of the IPS display screen can be shut down in time to avoid liquid crystal polarization.

[0052] The circuit principle of the liquid crystal voltage control circuit of this embodiment is as follows: Figures 7 to 13 As shown, the liquid crystal voltage control circuit includes a voltage supply module and a timing control module, and the voltage supply module includes a first voltage supply unit, a second voltage supply unit, a third voltage supply unit and a fourth voltage supply unit; the output ends of the first voltage supply unit, the second voltage supply unit, the third voltage supply unit and the fourth voltage supply unit are all connected to the input end of the timing control module, the main control MCU is connected to the control end of the timing control module, and the output end of the timing control module is connected to the IPS display screen;

[0053] When the IPS display screen is powered on, the main control MCU sequentially provides the fourth voltage, the first voltage, the second voltage and the third voltage to the IPS display screen through the timing control module; (i.e., the power-on timing sequence is VDD->AVDD->VGL->VGH) When the IPS display screen is powered off, the main control MCU controls the timing control module to sequentially power off the third voltage, the second voltage, the first voltage and the fourth voltage, and before powering off, the main control MCU stops providing the IPS display screen with RGB control signals and RGB data signals (i.e., the power-off timing sequence is VGH->VGL->AVDD->VDD);

[0054] Among them, the circuit schematic diagram of the voltage supply module is shown in Figure Figures 7 to 10As shown, the first voltage providing unit includes a voltage input unit, a booster U1, a diode D2, a feedback unit and a first filtering unit. The external power supply is connected to the input end of the booster U1 through the voltage input unit. The output end of the booster U1 provides a first voltage after passing through the diode D2. The feedback unit is used to feed back the first voltage to the booster U1. The first filtering unit is used to filter the first voltage. The second voltage providing unit includes a switching diode D4, a capacitor C9, a resistor R10, a diode D5 and a second filtering unit. The output end of the booster U1 is connected to the input end of the switching diode D4 through the capacitor C9. One output end of the switching diode D4 outputs the second voltage after passing through the resistor R10. The other output end of the switching diode D4 is grounded. The filtering unit is used to filter the second voltage, and the second voltage is grounded through a diode D5; the third voltage providing unit includes a switching diode D1, a capacitor C1, a resistor R1, a diode D3 and a third filtering unit, the output end of the booster U1 is connected to the input end of the switching diode D1 through the capacitor C1, one output end of the switching diode D1 outputs the third voltage through the resistor R1, and the other output end of the switching diode D1 is connected to the first voltage, and the third filtering unit is used to filter the third voltage, and the third voltage is grounded through a diode D3; the fourth voltage providing unit includes a voltage stabilizer U3, the input end of the voltage stabilizer U3 is connected to an external power supply, the enable end of the voltage stabilizer U3 is connected to the main control MCU, and the output end of the voltage stabilizer U3 outputs the fourth voltage. The specific connection method is shown in the figure. Figures 7 to 13 shown.

[0055] Specifically, Figure 2 This is the block diagram of the liquid crystal voltage control circuit. Figure 3 This is the LCD voltage power-on timing diagram. Figure 4 This is the LCD voltage power-off timing diagram. The function of the LCD voltage control circuit is to control the power-on and power-off sequence of AVDD, VGH, VGL and VDD through the GPIO1~GPIO4 of the main control MCU to meet the timing requirements of the display screen. Severe timing errors may cause electrical stress to the liquid crystal molecules, resulting in display failures such as display abnormality, screen flickering, image distortion or distortion, which will lead to liquid crystal polarization. The LCD power-on timing requirements are: VDD->AVDD->VGL->VGH->RGB data / control signal. After VDD is powered on, AVDD is powered on. After AVDD is powered on, there is a delay of at least 20ms, VGL is powered on, and finally VGH is powered on. After the four voltages are stable, the MCU sends the RGB signal; the LCD power-off timing requirements are: RGB data / control signal->VGH->VGL->AVDD->VDD. The MCU first turns off the RGB signal, delays for 10ms, then turns off the VGH voltage, then turns off the VGL voltage, and then turns off the AVDD voltage. After a delay of 10ms, the VDD voltage is finally turned off.

[0056] Furthermore, the timing control module is as follows Figures 10 to 13 As shown, it includes a first voltage switch control unit, a second voltage switch control unit and a third voltage switch control unit;

[0057] The first voltage switch control unit includes a switch tube Q3, a switch tube Q6, a resistor R32 and a resistor R29, the main control MCU is connected to the control end of the switch tube Q6 through the resistor R32, one switch end of the switch tube Q6 is grounded, the other switch end of the switch tube Q6 is connected to the control end of the switch tube Q3 through the resistor R29, one switch end of the switch tube Q3 is connected to the first voltage, and the other switch end of the switch tube Q3 is connected to the IPS display screen;

[0058] The third voltage switch control unit includes a switch tube Q2, a switch tube Q5, a resistor R31 and a resistor R28, the main control MCU is connected to the control end of the switch tube Q5 through the resistor R31, a switch end of the switch tube Q5 is grounded, the other switch end of the switch tube Q5 is connected to the control end of the switch tube Q2 through the resistor R28, a switch end of the switch tube Q2 is connected to the third voltage, and the other switch end of the switch tube Q2 is connected to the IPS display screen;

[0059] The second voltage switch control unit includes a switch tube Q1, a switch tube Q4, a switch tube Q7, a resistor R33, a resistor R30, a resistor R34 and a resistor R35. The main control MCU is connected to the control end of the switch tube Q7 through the resistor R33. A switch end of the switch tube Q7 is grounded. The other switch end of the switch tube Q7 is connected to the control end of the switch tube Q4 through the resistor R30. A switch end of the switch tube Q4 is connected to an external power supply through the resistor R35. The control end of the switch tube Q4 is connected to the external power supply through the resistor R34. The other switch end of the switch tube Q4 is connected to the control end of the switch tube Q1. A switch end of the switch tube Q1 is connected to the second voltage. The other switch end of the switch tube Q1 is connected to the IPS display screen. The specific circuit schematic diagram of the timing control module is as follows: Fig.10 Paper to Fig.13 shown.

[0060] Specifically, the working principle of the first voltage switch control unit is: when the first voltage needs to be provided or disconnected for the IPS display, the main control MCU controls the conduction of the switch tube Q6 through the port GPIO3, and then controls the conduction of the switch tube Q3 to achieve the provision and disconnection of the first voltage. The second and third voltages are the same, and will not be described here. The fourth voltage controls whether the voltage regulator U3 outputs voltage through GPIO4, thereby controlling the output of the fourth voltage.

[0061] The liquid crystal voltage detection circuit of this embodiment is as follows Figures 14 to 17As shown, it includes a first voltage detection unit, a second voltage detection unit, a third voltage detection unit and a fourth voltage detection unit;

[0062] The first voltage detection unit includes a resistor R6 and a resistor R13, the first voltage is connected to the main control MCU through the resistor R6, and one end of the resistor R6 connected to the main control MCU is grounded through the resistor R13;

[0063] The third voltage detection unit includes a resistor R7 and a resistor R14, the third voltage is connected to the main control MCU through the resistor R7, and one end of the resistor R7 connected to the main control MCU is grounded through the resistor R14;

[0064] The fourth voltage detection unit includes a resistor R5 and a resistor R12, the fourth voltage is connected to the main control MCU through the resistor R5, and one end of the resistor R5 connected to the main control MCU is grounded through the resistor R12;

[0065] The second voltage detection unit includes an amplifier, a resistor R21, a resistor R23, a resistor R20 and a resistor R22, one input end of the amplifier is connected to an external power supply, the second voltage is connected to another input end of the amplifier through the resistor R23, the other input end of the amplifier is also connected to a reference voltage Vref through the resistor R21, the output end of the amplifier is connected to the main control MCU through the resistor R20, and one end of the resistor R20 connected to the main control MCU is grounded through the resistor R22.

[0066] Specifically, the specific connection principle of the liquid crystal voltage detection circuit is as follows: Figures 14 to 17 As shown, the first voltage, the second voltage, the third voltage and the fourth voltage after voltage division are transmitted to the main control MCU in real time by voltage division, and the main control MCU determines whether there is an abnormality, so that the main control MCU can power off or shut down immediately to protect the liquid crystal in time. In this embodiment, ADC1 to ADC4 detect the voltages of VDD, AVDD, VGH and VGL respectively, and monitor the changes of each power supply voltage in real time. The voltage conversion formula is as follows:

[0067] VDD voltage = Vadc1x(R5+R12) / R12 = Vadc1x2;

[0068] AVDD voltage = Vadc2x(R6+R13) / R13 = Vadc2x6;

[0069] VGH voltage = Vadc3x(R7+R14) / R14 = Vadc2x11;

[0070] VGL voltage = 9.6-2*Vadc4; VREF = 9.6V.

[0071] The RGB control signal detection circuit of this embodiment includes a signal amplification module and a signal shaping module. The output end of the signal amplification module is connected to the input end of the signal shaping module. The RGB control signal output by the main control MCU to the IPS display screen is input to the main control MCU after the signal amplification effect of the signal amplification module and the signal shaping effect of the signal shaping module. The main control MCU determines whether the RGB control signal of the IPS display screen is abnormal based on the received shaped signal. When an abnormality occurs, the main control MCU shuts off the output of the RGB data signal and the RGB control signal, and cuts off the supply of the working voltage of the IPS display screen.

[0072] Specifically, the RGB control signal detection circuit is as follows: Figure 6 and 18 As shown, the frequency of RGB control signals such as PCLK, HSYNC, VSYNC and DEN is detected by Schmitt trigger. Once the control signal output by LCD controller is abnormal, the main control MCU will quickly cut off the supply of LCD power supply voltage. Among them, PCLK, HSYNC, VSYNC and DEN are RGB control signals output by LCD controller, and T1_PCLK, T2_HSYNC, T3_VSYNC and T4_DEN are connected to T1~T4 timers of main control MCU respectively. Main control MCU monitors whether the RGB control signal (PCLK / HSYNC / VSYNC / DEN) output by LCD controller is normal in real time. Once a signal is abnormal, the output of RGB data signal and other control signals will be turned off immediately, and the supply of external voltage (AVDD / VGH / VGL / VDD) will be cut off to avoid polarization of liquid crystal.

[0073] In this embodiment, each power supply voltage of the liquid crystal is controlled independently, and the power-on and power-off timing can be controlled strictly according to the timing requirements of the main control MCU to prevent the polarization of the liquid crystal caused by the power-on and power-off timing errors; the main control MCU monitors the power supply voltage of the liquid crystal in real time to see if it is abnormal. If any voltage abnormality occurs, other control signal outputs are turned off immediately and the liquid crystal power supply voltage output is cut off; the main control MCU monitors the RGB control signal output in real time. Once the RGB control signal is abnormal, the main control MCU can quickly turn off the RGB signal output and turn off the liquid crystal power supply voltage output according to the power-off timing to prevent the liquid crystal from polarizing; the drive control circuit has flexible control and comprehensive monitoring, which effectively avoids the liquid crystal polarization caused by abnormal signals or voltage.

[0074] Embodiment 2:

[0075] This embodiment provides a driving control method to prevent polarization of an IPS display screen. Fig.19 , including the following methods:

[0076] S1, the external power supply starts to supply power, and the liquid crystal voltage control circuit generates a first voltage, a second voltage, a third voltage and a fourth voltage;

[0077] S2, the main control MCU provides the IPS display screen with a fourth voltage, a first voltage, a second voltage and a third voltage in sequence through the timing control module;

[0078] S3, the main control MCU turns on the ADC detection channel, and detects in real time through the liquid crystal voltage detection circuit whether the first voltage, the second voltage, the third voltage and the fourth voltage are abnormal; if the voltage detection is abnormal, the main control MCU shuts off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage; if the voltage detection is normal, the main control MCU provides RGB data signals and RGB control signals for the IPS display;

[0079] S4, the main control MCU has a built-in timer, and regularly detects the RGB control signal through the RGB control signal detection circuit; if the detection is normal, the display of the IPS display screen and the backlight of the IPS display screen are turned on, and the IPS display screen starts to display normally; if the detection is abnormal, the main control MCU first turns off the output of the RGB data signal and the RGB control signal, and then turns off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage.

[0080] The specific working principle of this embodiment is:

[0081] After power-on, the main control MCU strictly follows the timing requirements of the LCD driver IC, and controls the power-on timing of the LCD power supply voltage AVDD, VGH, VGL and VDD voltage through GPIO1~GPIO4. The LCD controller sends RGB data signals and RGB control signals to the display screen respectively. After the display screen is turned on, the main control MCU monitors the LCD voltage AVDD, VGH, VGL and VDD in real time through ADC1~ADC4 to see if they are abnormal, and detects whether the RGB control signal (PCLK / HSYNC / VSYNC / DEN) is abnormal through the timer. Once the main control MCU detects that a certain voltage of the LCD is abnormal, the main control MCU immediately cuts off the supply of other voltages and turns off the output of the LCD controller to prevent the LCD from polarizing under abnormal voltage; in another case, once the main control MCU detects that a certain RGB control signal is abnormal, it immediately turns off all the LCD power supply voltages and turns off the data output of the LCD controller to prevent the LCD from polarizing under abnormal control signal conditions.

[0082] Among them, the working principle of the liquid crystal voltage control circuit is:

[0083] Figure 2 This is the block diagram of the liquid crystal voltage control circuit. Figure 2 This is the LCD voltage power-on timing diagram. Figure 3 The LCD voltage power-off timing diagram. The LCD voltage control circuit is used to control the power-on and power-off sequence of AVDD, VGH, VGL and VDD through GPIO1~GPIO4 of MCU to meet the timing requirements of the driver IC. Severe timing errors may cause electrical stress to the LCD driver chip or related control chip, resulting in display failures such as display abnormality, screen flickering, image distortion or distortion, and thus cause LCD polarization.

[0084] LCD power-on timing requirements: VDD->AVDD->VGL->VGH->RGB data / control signal;

[0085] LCD power-off timing requirements: RGB data / control signal->VGH->VGL->AVDD->VDD.

[0086] Working principle of LCD voltage detection circuit:

[0087] Figure 5 This is a block diagram of the liquid crystal voltage detection circuit. The function of the liquid crystal voltage detection circuit is: the main control MCU monitors the liquid crystal power supply voltage AVDD, VGH, VGL and VDD in real time to see if they are abnormal. Once an abnormal voltage occurs, the main control MCU will immediately cut off the external power supply voltage of the liquid crystal and close the data output of the LCD controller to prevent the liquid crystal from polarizing due to electrical stress caused by abnormal power supply voltage.

[0088] Working principle of RGB control signal detection circuit:

[0089] Figure 6 This module is an RGB control signal detection circuit. The main control MCU monitors in real time whether the RGB control signals (PCLK / HSYNC / VSYNC / DEN) output by the LCD controller are normal. Once a signal is abnormal, the output of the RGB data signal and other control signals will be shut down immediately, and the supply of external voltage (AVDD / VGH / VGL / VDD) will be cut off to avoid polarization of the liquid crystal.

[0090] The purpose of this embodiment is to provide a driving control device and method for preventing the polarization of an IPS display screen, aiming to improve the stability and reliability of an IPS display screen and prevent the polarization of liquid crystal under abnormal signals. Each power supply voltage of the liquid crystal is independently controlled, and the power-on and power-off timing can be strictly controlled according to the timing requirements of the main control MCU to prevent the polarization of the liquid crystal caused by the power-on and power-off timing errors; the main control MCU monitors the power supply voltage of the liquid crystal in real time to see if it is abnormal. If any voltage abnormality occurs, other control signal outputs are immediately turned off and the liquid crystal power supply voltage output is cut off; the main control MCU monitors the RGB control signal output in real time. Once the RGB control signal is abnormal, the main control MCU can quickly turn off the RGB signal output and turn off the liquid crystal power supply voltage output according to the power-off timing to prevent the liquid crystal from polarizing; the driving control circuit is flexible in control and comprehensive in monitoring, effectively avoiding the polarization of the liquid crystal caused by abnormal signals or voltages.

[0091] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A driving control device for preventing polarization of an IPS display screen, characterized in that: It includes a main control MCU, a liquid crystal voltage control circuit, a liquid crystal voltage detection circuit and an RGB control signal detection circuit; After the external power supply provides power to the liquid crystal voltage control circuit, the main control MCU controls the liquid crystal voltage control circuit to provide four working voltages to the IPS display screen in a time sequence; The liquid crystal voltage detection circuit detects the four working voltages of the IPS display screen in real time, and transmits the detection data to the main control MCU. The main control MCU determines whether the working voltage of the IPS display screen is abnormal according to the detection data. If an abnormality occurs, the main control MCU cuts off the working voltage of all IPS display screens and stops providing RGB control signals to the IPS display screen; The RGB control signal detection circuit is used to detect the RGB control signal provided to the IPS display screen, and transmit the detection data to the main control MCU. If the detection result is abnormal, the main control MCU shuts down the output of the RGB data signal and the RGB control signal, and cuts off the output of the liquid crystal voltage control circuit; The liquid crystal voltage control circuit includes a voltage supply module and a timing control module, and the voltage supply module includes a first voltage supply unit, a second voltage supply unit, a third voltage supply unit and a fourth voltage supply unit; the output ends of the first voltage supply unit, the second voltage supply unit, the third voltage supply unit and the fourth voltage supply unit are all connected to the input end of the timing control module, the main control MCU is connected to the control end of the timing control module, and the output end of the timing control module is connected to the IPS display screen; When the IPS display screen is powered on, the main control MCU sequentially provides the IPS display screen with a fourth voltage, a first voltage, a second voltage and a third voltage through the timing control module; When the IPS display screen is powered off, the main control MCU controls the timing control module to sequentially power off the third voltage, the second voltage, the first voltage and the fourth voltage, and before powering off, the main control MCU stops providing RGB control signals and RGB data signals to the IPS display screen.

2. A driving control device for preventing polarization of an IPS display screen according to claim 1, characterized in that: The first voltage providing unit includes a voltage input unit, a booster U1, a diode D2, a feedback unit and a first filtering unit, the external power supply is connected to the input end of the booster U1 through the voltage input unit, the output end of the booster U1 provides a first voltage after passing through the diode D2, the feedback unit is used to feed back the first voltage to the booster U1, and the first filtering unit is used to filter the first voltage; The second voltage providing unit includes a switching diode D4, a capacitor C9, a resistor R10, a diode D5 and a second filtering unit. The output end of the booster U1 is connected to the input end of the switching diode D4 through the capacitor C9. One output end of the switching diode D4 outputs the second voltage after passing through the resistor R10. The other output end of the switching diode D4 is grounded. The second filtering unit is used to filter the second voltage, and the second voltage is grounded through the diode D5. The third voltage providing unit includes a switching diode D1, a capacitor C1, a resistor R1, a diode D3 and a third filtering unit. The output end of the booster U1 is connected to the input end of the switching diode D1 through the capacitor C1, one output end of the switching diode D1 outputs the third voltage through the resistor R1, and the other output end of the switching diode D1 is connected to the first voltage. The third filtering unit is used to filter the third voltage, and the third voltage is grounded through the diode D3; The fourth voltage providing unit includes a voltage stabilizer U3, an input end of the voltage stabilizer U3 is connected to an external power supply, an enable end of the voltage stabilizer U3 is connected to the main control MCU, and an output end of the voltage stabilizer U3 outputs a fourth voltage.

3. The driving control device for preventing polarization of an IPS display screen according to claim 1, characterized in that: The timing control module includes a first voltage switch control unit, a second voltage switch control unit and a third voltage switch control unit; The first voltage switch control unit includes a switch tube Q3, a switch tube Q6, a resistor R32 and a resistor R29, the main control MCU is connected to the control end of the switch tube Q6 through the resistor R32, one switch end of the switch tube Q6 is grounded, the other switch end of the switch tube Q6 is connected to the control end of the switch tube Q3 through the resistor R29, one switch end of the switch tube Q3 is connected to the first voltage, and the other switch end of the switch tube Q3 is connected to the IPS display screen; The third voltage switch control unit includes a switch tube Q2, a switch tube Q5, a resistor R31 and a resistor R28, the main control MCU is connected to the control end of the switch tube Q5 through the resistor R31, a switch end of the switch tube Q5 is grounded, the other switch end of the switch tube Q5 is connected to the control end of the switch tube Q2 through the resistor R28, a switch end of the switch tube Q2 is connected to the third voltage, and the other switch end of the switch tube Q2 is connected to the IPS display screen; The second voltage switch control unit includes a switch tube Q1, a switch tube Q4, a switch tube Q7, a resistor R33, a resistor R30, a resistor R34 and a resistor R35. The main control MCU is connected to the control end of the switch tube Q7 through the resistor R33. A switch end of the switch tube Q7 is grounded. The other switch end of the switch tube Q7 is connected to the control end of the switch tube Q4 through the resistor R30. A switch end of the switch tube Q4 is connected to an external power supply through the resistor R35. The control end of the switch tube Q4 is connected to the external power supply through the resistor R34. The other switch end of the switch tube Q4 is connected to the control end of the switch tube Q1. A switch end of the switch tube Q1 is connected to the second voltage, and the other switch end of the switch tube Q1 is connected to the IPS display screen.

4. The driving control device for preventing polarization of an IPS display screen according to claim 1, characterized in that: The liquid crystal voltage detection circuit includes a first voltage detection unit, a second voltage detection unit, a third voltage detection unit and a fourth voltage detection unit; The first voltage detection unit includes a resistor R6 and a resistor R13, the first voltage is connected to the main control MCU through the resistor R6, and one end of the resistor R6 connected to the main control MCU is grounded through the resistor R13; The third voltage detection unit includes a resistor R7 and a resistor R14, the third voltage is connected to the main control MCU through the resistor R7, and one end of the resistor R7 connected to the main control MCU is grounded through the resistor R14; The fourth voltage detection unit includes a resistor R5 and a resistor R12, the fourth voltage is connected to the main control MCU through the resistor R5, and one end of the resistor R5 connected to the main control MCU is grounded through the resistor R12; The second voltage detection unit includes an amplifier, a resistor R21, a resistor R23, a resistor R20 and a resistor R22, one input end of the amplifier is connected to an external power supply, the second voltage is connected to another input end of the amplifier through the resistor R23, the other input end of the amplifier is also connected to a reference voltage Vref through the resistor R21, the output end of the amplifier is connected to the main control MCU through the resistor R20, and one end of the resistor R20 connected to the main control MCU is grounded through the resistor R22.

5. The driving control device for preventing polarization of an IPS display screen according to claim 1, characterized in that: The RGB control signal detection circuit includes a signal amplification module and a signal shaping module. The output end of the signal amplification module is connected to the input end of the signal shaping module. The RGB control signal output by the main control MCU to the IPS display screen is input to the main control MCU after the signal amplification effect of the signal amplification module and the signal shaping effect of the signal shaping module. The main control MCU determines whether the RGB control signal of the IPS display screen is abnormal according to the received shaped signal. When an abnormality occurs, the main control MCU shuts off the output of the RGB data signal and the RGB control signal, and cuts off the supply of the working voltage of the IPS display screen.

6. A driving control method for preventing polarization of an IPS display screen, applied to the driving control device for preventing polarization of an IPS display screen according to any one of claims 1 to 5, characterized in that: The following steps are involved: The external power supply starts supplying power, and generates a first voltage, a second voltage, a third voltage, and a fourth voltage through the liquid crystal voltage control circuit; The main control MCU sequentially provides the fourth voltage, the first voltage, the second voltage and the third voltage to the IPS display screen through the timing control module; The main control MCU turns on the ADC detection channel and detects in real time through the liquid crystal voltage detection circuit whether the first voltage, the second voltage, the third voltage and the fourth voltage are abnormal; If the voltage detection is abnormal, the main control MCU shuts off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage; if the voltage detection is normal, the main control MCU provides RGB data signals and RGB control signals to the IPS display; The main control MCU sets a timer and periodically detects the RGB control signal through the RGB control signal detection circuit; if the detection is normal, the display of the IPS display screen and the backlight of the IPS display screen are turned on, and the IPS display screen starts to display normally; if the detection is abnormal, the main control MCU first turns off the output of the RGB data signal and the RGB control signal, and then turns off the provision of the first voltage, the second voltage, the third voltage and the fourth voltage.

Images