Liquid crystal display driving device and electronic equipment

Abstract

The present invention discloses a liquid crystal display driving device and electronic device, relating to the field of integrated circuits. The driving device includes a voltage divider circuit, a voltage stabilizing circuit, a first switch, and a controller. The voltage divider circuit is used to divide an input voltage. The first end of the first switch is connected to the output end of the voltage divider circuit, the second end is connected to an electrode of a liquid crystal display device, and the third end is connected to an electrode of the liquid crystal display device via the voltage stabilizing circuit. The voltage stabilizing circuit is used to stabilize the output voltage of the voltage divider circuit. The controller is used to control the connection between the first end of the first switch and the second end or the third end according to changes in the input voltage. The present invention divides and stabilizes the input voltage using the voltage divider circuit and the voltage stabilizing circuit. The controller controls the switching between the voltage divider circuit and the electrode of the liquid crystal display device according to changes in the input voltage to control the voltage output to the liquid crystal display device, thereby adapting to the application of a wide operating voltage system without affecting the liquid crystal display effect.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit design, and in particular to a liquid crystal display driving device and electronic equipment. Background Art

[0002] The driving and control of liquid crystal displays is used to adjust the phase, peak value, and frequency of the potential signal applied to the electrodes of the liquid crystal display device, establish a driving electric field, and achieve the display effect of the liquid crystal display device. When driving the liquid crystal display, it is not advisable to apply a DC voltage, otherwise it will cause electrolysis of the liquid crystal and aging of the electrodes, which will greatly reduce the service life of the liquid crystal display. Therefore, the liquid crystal display must be driven by an AC voltage. Because the change in the optical properties of the liquid crystal under the action of an electric field relies on the elastic deformation of the liquid crystal as an elastic continuum, its response time is long. Therefore, the effect of the alternating driving voltage does not depend on its peak value, and the change in the liquid crystal transmittance is only related to the effective value of the applied voltage. At the same time, the effect of positive and negative voltages is the same.

[0003] Currently, the driving devices for liquid crystal displays on the market can only be controlled by applying a fixed operating voltage, which is generally 3.3V or 5V. The operating voltage is evenly divided by multiple resistors to obtain multiple driving voltages for applying to the electrodes of the liquid crystal display device. The values ​​of these driving voltages are generally fixed, so the corresponding lighting effects are also fixed. It is impossible to change the display effect of the liquid crystal display device by adjusting the operating voltage of the driving device, and its application is limited. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that liquid crystal display devices cannot adapt to the application of a wide operating voltage of the system, and to provide a liquid crystal display driving device and an electronic device.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] In a first aspect, the present invention provides a driving device for a liquid crystal display, comprising a voltage divider circuit, a voltage stabilizing circuit, a first switch, and a controller;

[0007] The voltage divider circuit is used to divide the input voltage;

[0008] The first end of the first switch is connected to the output end of the voltage divider circuit, the second end is connected to the electrode of the liquid crystal display device, and the third end is connected to the electrode of the liquid crystal display device through the voltage stabilizing circuit; the voltage stabilizing circuit is used to stabilize the output voltage of the voltage divider circuit;

[0009] The controller is configured to control the first end of the first switch to be connected to the second end or the third end according to a change in the input voltage.

[0010] Preferably, the controller is specifically used to control the first end of the first switch to be connected to the third end when the input voltage is less than a preset threshold, and to control the first end of the first switch to be connected to the second end when the input voltage is greater than or equal to the preset threshold.

[0011] Preferably, the driving device further comprises a second switch, and the voltage divider circuit comprises a first output terminal and a second output terminal, wherein the voltage output by the first output terminal is different from the voltage output by the second output terminal;

[0012] The first end of the first switch is connected to the first output end of the voltage divider circuit, and the second end of the first switch and the output end of the voltage stabilizing circuit are both connected to the first end of the second switch;

[0013] The second output terminal of the voltage divider circuit is connected to the second terminal of the second switch, and the third terminal of the second switch is connected to the electrode of the liquid crystal display device;

[0014] The controller is used to control the third end of the second switch to be connected to the first end of the second switch or the second end of the second switch according to the lighting effect.

[0015] Preferably, the driving device further includes a monitoring circuit for monitoring changes in the input voltage, and an output end of the monitoring circuit is connected to the controller.

[0016] Preferably, the voltage stabilization circuit includes a low-dropout linear regulator;

[0017] Preferably, the voltage stabilization circuit includes a bandgap reference voltage source.

[0018] Preferably, the driving device further comprises a power supply circuit for providing the input voltage to the voltage divider circuit.

[0019] Preferably, the electrodes include target row electrodes; wherein the target row electrodes are determined according to positions of pixels to be lit in the liquid crystal display device.

[0020] Preferably, the electrodes further include a target column electrode; wherein the target column electrode is determined according to the position of the pixel to be lit in the liquid crystal display device.

[0021] Preferably, the first switch is a single-pole double-throw switch.

[0022] In a second aspect, the present invention provides an electronic device comprising the driving device as described in the first aspect.

[0023] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0024] The positive progressive effect of the present invention is that: the present invention discloses a liquid crystal display driving device and electronic equipment, which divides the input voltage through a voltage divider circuit, stabilizes the output voltage of the voltage divider circuit through a voltage stabilizing circuit, and controls the on-off switching between the voltage divider circuit and the electrodes of the liquid crystal display device according to the change of the input voltage to control the voltage output to the liquid crystal display device, thereby adapting to the application of a wide operating voltage of the system without affecting the liquid crystal display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of an implementation of a driving device for a liquid crystal display according to Example 1 of the present invention;

[0026] Figure 2 This is another schematic diagram of an implementation of the liquid crystal display driving device of Example 1 of the present invention;

[0027] Figure 3 This is a schematic structural diagram of a matrix electrode of a liquid crystal display driving device according to Example 1 of the present invention;

[0028] Figure 4 This is a schematic diagram of an effect of the driving device for liquid crystal display according to Example 1 of the present invention;

[0029] Figure 5 This is another schematic diagram of the effect of the driving device for liquid crystal display according to Example 1 of the present invention;

[0030] Figure 6 This is another schematic diagram of an implementation of the liquid crystal display driving device of Example 1 of the present invention;

[0031] Figure 7 This is another schematic diagram of an implementation of the liquid crystal display driving device of Example 1 of the present invention;

[0032] Figure 8 This is another schematic diagram showing the effect of the driving device for liquid crystal display according to embodiment 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0034] Example 1

[0035] This embodiment provides a driving device for a liquid crystal display. Figure 1 FIG. 1 is a schematic diagram of an implementation of a driving device for a liquid crystal display according to this embodiment. Figure 1 As shown, the driving device 1 includes a voltage divider circuit 11, a voltage stabilizing circuit 121, a first switch 131 and a controller 14;

[0036] The voltage divider circuit 11 is used to divide the input voltage;

[0037] The first end of the first switch 131 is connected to the output end of the voltage divider circuit 11, the second end is connected to the electrode of the liquid crystal display device 2, and the third end is connected to the electrode of the liquid crystal display device 2 through the voltage stabilizing circuit 121; the voltage stabilizing circuit 121 is used to stabilize the output voltage of the voltage divider circuit 11;

[0038] The controller 14 is configured to control the first end of the first switch 131 to be connected to the second end or the third end according to a change in the input voltage.

[0039] It should be noted that the driving of the liquid crystal display is achieved by adjusting the potential signal applied to the liquid crystal display device to establish a driving electric field, so as to achieve the display effect of the liquid crystal display device.

[0040] The driving device 1 provided in this embodiment divides the input voltage applied to the driving device 1 by a voltage divider circuit 11 to obtain two output voltages for application to the electrodes of the liquid crystal display device 2. The controller 14 controls the on / off switching of a first switch between the voltage divider circuit 11 and the liquid crystal display device 2 according to changes in the input voltage, thereby selecting the desired output voltage. When the input voltage is in a low voltage state, the output voltage after voltage division and low voltage stabilization by the voltage stabilization circuit 121 is selected. The driving device 1 of this embodiment can adapt to an input voltage range of 2V to 5.5V. Without affecting the liquid crystal display effect, the desired output voltage for driving the electrodes of the liquid crystal display device 2 can be selected according to changes in the input voltage. Therefore, the driving device 1 provided in this embodiment can well adapt to applications and requirements of systems with a wide operating voltage range.

[0041] In an optional embodiment, the controller 14 is specifically used to control the first end of the first switch 131 to be connected to the third end when the input voltage is less than a preset threshold, and to control the first end of the first switch 131 to be connected to the second end when the input voltage is greater than or equal to the preset threshold.

[0042] In specific implementation, Figure 1As shown, when the controller 14 detects that the input voltage is less than a preset threshold, it controls the first end of the first switch 131 to connect to the third end. At this time, the output voltage is the voltage that has been low-voltage stabilized by the voltage stabilization circuit 121. The voltage stabilization circuit maintains it at a stable voltage, so the output voltage at this time will not decrease indefinitely as the input voltage decreases. The stable voltage is the voltage value corresponding to the output voltage when the input voltage is at the preset threshold. When the controller 14 detects that the input voltage is greater than or equal to the preset threshold, it controls the first end of the first switch 131 to connect to the second end. At this time, the output voltage is the output voltage directly connected to the electrode of the liquid crystal display device 2 through the resistor, which changes with changes in the input voltage.

[0043] In an optional embodiment, as Figure 2 As shown, the driving device further includes a second switch 132, and the voltage divider circuit 11 includes a first output terminal and a second output terminal, wherein the voltage output by the first output terminal is different from the voltage output by the second output terminal;

[0044] A first end of the first switch 131 is connected to the first output end of the voltage divider circuit 11 , and a second end of the first switch 131 and the output end of the voltage stabilizing circuit 121 are both connected to a first end of the second switch 132 ;

[0045] The second output terminal of the voltage divider circuit 11 is connected to the second terminal of the second switch 132, and the third terminal of the second switch 132 is connected to the electrode of the liquid crystal display device 2;

[0046] The controller 14 is configured to control the third end of the second switch 132 to be connected to the first end of the second switch 132 or the second end of the second switch 132 according to the lighting effect.

[0047] In a specific implementation, the output voltage at the first output terminal of the voltage divider circuit 11 is recorded as V2, and the output voltage at the second output terminal is recorded as V1. After being divided by the voltage divider circuit 11, the voltage values ​​of V1 and V2 are different. Therefore, when the third terminal of the second switch 132 is connected to the second terminal of the second switch 132, the output voltage is V1, and when the first terminal of the second switch 132 is connected to the third terminal of the second switch 132, the output voltage is V2.

[0048] The lighting effect of the liquid crystal display is proportional to the size of the driving voltage applied to the electrode. The larger the driving voltage, the brighter the lighting effect, and vice versa. The controller can select V1 or V2 to output to the electrode of the liquid crystal display device according to the lighting effect required by the liquid crystal display device.

[0049] It should be noted that Figure 3 Schematic diagram of the structure of the matrix electrode of the liquid crystal display driving device of this embodiment, which is composed of row electrodes from row 1 to row electrodes from row 1 to row electrodes from row 1 to column electrodes from column 1 to column electrodes from column 1 to column electrodes from column 1 to column electrodes from column 1 to column 1. Figure 3 As shown, a matrix structure is implemented in the fabrication and arrangement of LCD electrodes. This means that the back electrodes of a horizontal group of display pixels are connected together, known as row electrodes; while the segment electrodes of a vertical group of display pixels are connected together, known as column electrodes. Each display pixel on an LCD is uniquely identified by its row and column position.

[0050] The dynamic driving method of liquid crystal display is to cyclically apply selection pulses to the row electrodes, and at the same time give corresponding selection or non-selection driving pulses to the column electrodes of all display data, so as to realize the display function of all display pixels in a row being on or off. This row scanning is carried out row by row in sequence, and the cycle period is very short, so that the LCD screen presents a stable display effect.

[0051] The electrodes on a liquid crystal display device are driven independently of each other. A driving voltage is applied simultaneously and continuously to the pixel electrode and the common electrode until the display time ends. During the display period, the driving voltage is maintained to fully drive the liquid crystal.

[0052] It should be noted that the dynamic driving waveform of the liquid crystal display (LCD) has three indicators: driving voltage (V), which is the difference (peak-to-peak value) between the segment voltage applied to the lit part and the common voltage; duty cycle (Duty), in order to reduce the hardware driving circuit of the liquid crystal display (LCD), a multi-channel drive is adopted. The driving voltage of the liquid crystal display (LCD) is an AC waveform. The duty cycle of the driving waveform of the liquid crystal display (LCD) is the ratio of the part that is higher than the threshold voltage for lighting in one cycle; bias ratio (Bias), which is the ratio of the effective value of the voltage of the non-lit pixel (non-selected point) in the liquid crystal display (LCD) to the effective value of the voltage of the lit pixel (selected point).

[0053] The driving waveform of the liquid crystal display (LCD) consists of several levels. To prevent uneven contrast, a certain voltage is still applied to the electrodes corresponding to the unlit pixels. This is important for reducing the cross-interference caused by the lit pixels and preventing uneven contrast.

[0054] Figure 4 It is the control voltage when the pixel at row electrode n and column electrode m is lit in a certain frame display. Row scanning is performed row by row. In the case of row electrode n, the row electrode is only driven for one Nth of the frame period in a certain frame. At the same time, a reverse driving voltage is applied to the column electrode m where the pixel needs to be lit, so that the voltage difference between the row electrode and the column electrode is maximized to achieve the best display effect. Figure 4 At the same time, the electrodes that do not need to light up the pixels in the same frame are still given a certain driving voltage, which is important for reducing the cross interference caused by the lit pixels and preventing uneven contrast, as shown in the gray bottom part. Figure 4The non-grey bottom part is shown.

[0055] Usually, the ratio of the effective value of the voltage of the non-lit pixel to the effective value of the voltage of the lit pixel is designed to be a constant, that is, Figure 4 As shown in the figure, v4-v1 is the effective value of the voltage of the lit pixel, and v3-v2 is the effective value of the voltage of the non-lit pixel. The ratio of the two is the bias ratio 1 / n, where n=3. However, if the operating voltage is reduced, that is, v4-v1 becomes smaller, although the driving control effect of the effective value of the voltage of the lit pixel is not affected, v3-v2 will also become smaller at this time, which may not effectively reduce the cross-interference generated by the lit pixel, and may also cause uneven display contrast. Therefore, if Figure 5 As shown, it is necessary to optimize the design of the effective value of the voltage of the non-lit pixels so that under the condition of low operating voltage, the effective value of the voltage of the non-lit pixels does not decrease infinitely with the decrease of the operating voltage, that is, to change the ratio of the effective value of the voltage of the non-lit pixels to the effective value of the voltage of the lit pixels.

[0056] It should be noted that the distribution of lit pixels and non-lit pixels on the liquid crystal display device can be pre-programmed by the controller according to the lighting effect requirements. The effective value of voltage is the difference between the driving voltage of the row electrode and the driving voltage of the column electrode on a pixel.

[0057] In an optional embodiment, as Figure 6 As shown, the driving device 1 further includes a third switch 133 and a second voltage stabilizing circuit 121 . The voltage divider circuit 11 includes a first output terminal, a second output terminal, a third output terminal and a fourth output terminal, wherein the voltages output by the four output terminals are different.

[0058] In specific implementation, Figure 6 As shown, the first end 131 of the first switch 131 is connected to the first output end of the voltage divider circuit 11, the second end of the first switch 131 and the output end of the voltage stabilizing circuit 121 are both connected to the first input end of the second switch 132; the second output end of the voltage divider circuit 11 is connected to the second input end of the second switch 132; the first end of the third switch 133 is connected to the third output end of the voltage divider circuit 11, the second end of the third switch 133 is connected to the third input end of the second switch 132, and the third end of the third switch 133 is connected to the fourth input end of the second switch 132 through the second voltage stabilizing circuit 121; the output end of the second switch 132 is connected to the electrode of the liquid crystal display device 2.

[0059] The controller 14 controls the output end of the second switch 132 to be connected to the first input end, the second input end, the third input end or the fourth input end of the second switch 132 according to the lighting effect, thereby selecting the required output voltage for controlling the lighting effect of the liquid crystal display device 2.

[0060] Figure 7 FIG. 1 is a schematic diagram showing an implementation of a driving device for a liquid crystal display according to the present invention. Figure 7 As shown, the controller 14 monitors the input voltage and implements voltage division control of the four output voltages v1 to v4 through the voltage divider circuit 11 and the voltage stabilizing circuits 121 and 122, and then selects the required output voltage according to the required lighting effect and inputs it to the row electrodes and column electrodes of the liquid crystal display device 2 to drive the liquid crystal display device 2 and realize the display function of the liquid crystal display device.

[0061] like Figure 8 As shown, when controller 14 detects a low operating voltage condition, i.e., when the input voltage drops to a preset threshold, the voltage stabilization circuit maintains the voltages of V2 and V3 at the set values, and their output potential signals do not change with the input voltage. The output potential signals of V1 and V4 can change with the operating voltage. Conversely, when the input voltage is higher than the preset threshold, voltage divider circuit 11 typically divides the voltages of V1 to V4 equally through resistors, and their output potential signals can change with the operating voltage, thereby achieving a better display effect in a wide input voltage system solution.

[0062] It should be noted that the output terminals of the voltage divider circuit 11 of this embodiment are not limited to one output terminal, two output terminals or four output terminals as described in the above examples, and the specific number of output terminals can be determined according to actual needs.

[0063] In an optional embodiment, the driving device 1 further includes a monitoring circuit for monitoring changes in the input voltage, and an output end of the monitoring circuit is connected to the controller.

[0064] The monitoring circuit can be used to monitor changes in the input voltage and send the monitored signal to the controller 14 in real time. The controller 14 controls the required output voltage to be input to the electrodes of the liquid crystal display device 2 according to the changes in the received input voltage.

[0065] In an optional implementation, the voltage stabilization circuit includes a low-dropout linear regulator.

[0066] A low dropout regulator (LDO) uses a transistor or field-effect transistor operating in its saturation region to subtract excess voltage from the applied input voltage to produce a regulated output voltage. This voltage is maintained within 100mV of its rated value, which is the minimum difference between the input and output voltages required. LDOs offer low quiescent current and low noise, making them an ideal choice for systems with close input and output voltages, achieving high efficiency.

[0067] In an optional embodiment, the voltage stabilization circuit includes a bandgap reference voltage source.

[0068] The basic principle of a bandgap voltage reference is to use the positive temperature drift of a resistor's voltage drop to compensate for the negative temperature drift of a transistor's emitter junction's forward voltage drop, thereby achieving zero temperature drift. Because it doesn't use a Zener diode operating in reverse breakdown, it achieves extremely low noise voltage. Bandgap voltage references also feature low quiescent current, a narrow supply voltage range, and excellent long-term stability, making them suitable for low-power applications.

[0069] In an optional embodiment, the driving device 1 further includes a power supply circuit for providing an input voltage to the voltage divider circuit.

[0070] Specifically, the input voltage applied by the power supply circuit to the driving device 1 is in the range of 2V to 5.5V, so the output voltage values ​​after voltage division by the voltage divider circuit 11 are all within the range of the input voltage.

[0071] In an optional embodiment, the electrode includes a target row electrode; wherein the target row electrode is determined according to the position of the pixel to be illuminated in the liquid crystal display device.

[0072] Each display pixel on a liquid crystal display device is uniquely determined by the position of its row electrode and column electrode.

[0073] In an optional embodiment, the electrode further includes a target column electrode; wherein the target column electrode is determined according to the position of the pixel to be illuminated in the liquid crystal display device.

[0074] In an optional embodiment, the first switch is a single-pole double-throw switch;

[0075] The second switch is a multiplexer, such as a multiplexer with four inputs and a single output; the third switch is a single-pole double-throw switch.

[0076] This embodiment provides a liquid crystal display driving device, which divides the input voltage through a voltage divider circuit, and stabilizes the output voltage of the voltage divider circuit through a voltage stabilization circuit. A controller controls the on-off switching between the voltage divider circuit and the electrodes of the liquid crystal display device according to changes in the input voltage to control the voltage output to the liquid crystal display device, thereby adapting to the application of a wide operating voltage of the system without affecting the liquid crystal display effect.

[0077] Example 2

[0078] This embodiment provides an electronic device, including the driving device described in Embodiment 1.

[0079] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A driving device for a liquid crystal display, characterized in that: It includes a voltage dividing circuit, a voltage stabilizing circuit, a first switch and a controller; The voltage divider circuit is used to divide the input voltage; The first end of the first switch is connected to the output end of the voltage divider circuit, the second end is connected to the electrode of the liquid crystal display device, and the third end is connected to the electrode of the liquid crystal display device through the voltage stabilizing circuit; the voltage stabilizing circuit is used to stabilize the output voltage of the voltage divider circuit; The controller is configured to control the first end of the first switch to be connected to the second end or the third end according to a change in the input voltage; The driving device further includes a second switch, and the voltage divider circuit includes a first output terminal and a second output terminal, wherein the voltage output by the first output terminal is different from the voltage output by the second output terminal; The first end of the first switch is connected to the first output end of the voltage divider circuit, and the second end of the first switch and the output end of the voltage stabilizing circuit are both connected to the first end of the second switch; The second output terminal of the voltage divider circuit is connected to the second terminal of the second switch, and the third terminal of the second switch is connected to the electrode of the liquid crystal display device; The controller is used to control the third end of the second switch to be connected to the first end of the second switch or the second end of the second switch according to the lighting effect.

2. The liquid crystal display driving device according to claim 1, wherein: The controller is specifically configured to control the first end of the first switch to be connected to the third end when the input voltage is less than a preset threshold, and to control the first end of the first switch to be connected to the second end when the input voltage is greater than or equal to the preset threshold.

3. The driving device for liquid crystal display according to claim 1, wherein: The driving device further includes a monitoring circuit for monitoring changes in the input voltage, and an output end of the monitoring circuit is connected to the controller.

4. The liquid crystal display driving device according to claim 1, wherein: The voltage stabilizing circuit includes a low voltage dropout linear regulator; And / or, the voltage stabilization circuit includes a bandgap reference voltage source.

5. The liquid crystal display driving device according to claim 1, wherein: The driving device further includes a power supply circuit for providing the input voltage to the voltage divider circuit.

6. The driving device for liquid crystal display according to claim 1, wherein: The electrodes include target row electrodes; wherein the target row electrodes are determined according to positions of pixels to be lit in the liquid crystal display device.

7. The liquid crystal display driving device according to claim 1, wherein: The electrodes further include a target column electrode; wherein the target column electrode is determined according to the position of the pixel to be lit in the liquid crystal display device.

8. The liquid crystal display driving device according to claim 1, wherein: The first switch is a single-pole double-throw switch.

9. An electronic device, characterized in that: The drive device comprises the drive device according to any one of claims 1 to 8.

Images