Voltage detection circuit and display device

Abstract

The utility model discloses a kind of voltage detection circuit and display device, voltage detection circuit includes adjusting unit and voltage comparison unit, wherein, the input end of the adjusting unit is connected to the input end and / or output end of display driving chip in the display device, and / or be connected to the power input end and / or power output end of light source driving chip in the display device, for obtaining the input voltage and / or output voltage of the display driving chip, and / or, obtain the power input voltage and / or output voltage of the light source driving chip, and make the input voltage and / or output voltage of the obtained adaptation the working voltage of the voltage comparison unit;The input end of the voltage comparison unit is connected the output end of the adjusting unit, for detecting whether the input voltage and / or output voltage obtained by the adjusting unit is overvoltage / undervoltage, and the output end of the voltage comparison unit is as the output end of the voltage detection circuit.

Description

Technical Field

[0001] This utility model relates to the field of display technology, and more specifically to a voltage detection circuit and display device. Background Technology

[0002] Liquid crystal display (LCD) devices include LCD (Liquid Crystal Display) modules and backlight modules that provide light to the LCD modules to display images. They are used in smart devices such as smart medical devices, smart home appliances, and autonomous vehicles, allowing users to interact with the device's central control system. However, during the use of smart devices, LCD devices may experience screen blackouts due to abnormal voltage (such as overvoltage or undervoltage), affecting device operation and potentially causing serious safety accidents such as fires or electric shocks. Utility Model Content

[0003] This utility model provides a voltage detection circuit and display device to automatically detect whether the voltage of the display device is abnormal, thereby solving the technical problem that abnormal voltage affects the operation of existing liquid crystal display devices.

[0004] To solve the above-mentioned technical problems, according to one aspect of the present invention, a voltage detection circuit is provided, applied to a display device. The voltage detection circuit includes an adjustment unit and a voltage comparison unit, wherein... The input terminal of the adjustment unit is connected to the input terminal and / or output terminal of the display driver chip in the display device, and / or connected to the power input terminal and / or power output terminal of the light source driver chip in the display device, for obtaining the input voltage and / or output voltage of the display driver chip, and / or obtaining the power input voltage and / or output voltage of the light source driver chip, and adapting the obtained input voltage and / or output voltage to the operating voltage of the voltage comparison unit; The input terminal of the voltage comparison unit is connected to the output terminal of the adjustment unit, and is used to detect whether the input voltage and / or output voltage obtained by the adjustment unit is over-voltage or under-voltage. The output terminal of the voltage comparison unit serves as the output terminal of the voltage detection circuit.

[0005] To solve the above-mentioned technical problems, according to another aspect of the present invention, a display device is also provided, comprising a display module, a light source module, an MCU, and the aforementioned voltage detection circuit, wherein... The display module includes a display screen and a display driver chip, wherein the display driver chip is used to drive the display screen to display images; The light source module includes a light source display module and a light source driver chip. The light source driver chip is used to adjust the brightness of the light source display module according to the dimming signal from the MCU. The input terminal of the voltage detection circuit is connected to the input terminal and / or output terminal of the display driver chip, and / or to the power input terminal and / or power output terminal of the light source driver chip, for detecting whether the input voltage / output voltage of the display driver chip and / or the power input voltage / output voltage of the light source driver chip are over-voltage / under-voltage.

[0006] Compared with the prior art, the voltage detection circuit of this utility model is equipped with an adjustment unit and a voltage comparison unit. The adjustment unit can be connected to the input and / or output terminals of the display driver chip and / or the light source driver chip in the display device to obtain the input voltage and / or output voltage of the display driver chip and / or the light source driver chip, and adapt the obtained input voltage and / or output voltage to the working voltage of the voltage comparison unit. The voltage comparison unit detects whether the input voltage and output voltage of the display driver chip and / or the power input voltage or output voltage of the light source driver chip are over-voltage or under-voltage, thereby realizing the automatic detection of various abnormal voltages of the display device. This allows users to intervene in a timely manner, thereby avoiding the impact of abnormal voltage on the operation of the equipment. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the circuit block of the voltage detection circuit provided in this embodiment of the present invention.

[0008] Figure 2 This is a schematic diagram of the specific circuit structure of the first adjustment circuit in the voltage detection circuit provided in this embodiment of the utility model.

[0009] Figure 3 This is a schematic diagram of the specific circuit structure of the reference adjustment circuit in the voltage detection circuit provided in this embodiment of the utility model.

[0010] Figure 4 This is a schematic diagram of the specific circuit structure of the voltage comparison unit and alarm circuit in the voltage detection circuit provided in this embodiment of the utility model.

[0011] Figure 5 This is a schematic circuit block diagram of the liquid crystal display device provided in an embodiment of the present invention.

[0012] Figure 6 This is a schematic diagram of the specific circuit structure of the MCU in the liquid crystal display device provided in this embodiment of the utility model.

[0013] Reference numerals: 10-Voltage detection circuit; 11-Adjustment unit; 111-First adjustment circuit; 12-Voltage comparison unit; 13-Alarm circuit; 14-Reference adjustment circuit; 30-LCD module; 31-Liquid crystal display screen; 32-LCD driver chip; 40-Backlight module; 41-Backlight display module; 42-Backlight driver chip. Detailed Implementation

[0014] To enable those skilled in the art to more clearly understand the purpose, technical solution and advantages of this utility model, the present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0015] Reference Figures 1 to 4 , Figures 1 to 4 A specific embodiment of the voltage detection circuit 10 of this utility model is shown. The voltage detection circuit 10 of this utility model can be applied to display devices such as liquid crystal display devices, self-emissive display devices, and electronic paper devices. The display driver chip of the display device can drive LED display, LCD display, or electronic paper display, and the light source driver chip can drive front light or back light display. In the embodiment shown in the accompanying drawings, the voltage detection circuit 10 includes an adjustment unit 11 and a voltage comparison unit 12. The input terminal of the adjustment unit 11 serves as the input terminal of the voltage detection circuit 10, receiving the voltage being detected. Specifically, the input terminal of the adjustment unit 11 can be connected to the input and / or output terminal of the display driver chip in the display device, and / or to the power input and / or power output terminal of the light source driver chip, for acquiring the input voltage and / or output voltage of the display driver chip, and / or acquiring the power input voltage and / or power output voltage of the light source driver chip, and adapting the acquired input voltage and / or output voltage to the operating voltage of the voltage comparison unit 12. The input terminal of the voltage comparison unit 12 is connected to the output terminal of the adjustment unit 11, for detecting whether the input voltage and / or output voltage acquired by the adjustment unit 11 is over-voltage or under-voltage. The output terminal of the voltage comparison unit 12 can serve as the output terminal of the voltage detection circuit 10, and can be connected to the MCU of the display device. When an abnormal voltage is detected, it outputs an abnormal signal to the display device to alert the user that the voltage is abnormal. Based on the above design, in this embodiment, the voltage detection circuit 10 can detect the input voltage and output voltage of the display driver chip and / or the power input voltage and power output voltage of the light source driver chip, thereby realizing the automatic detection of various abnormal voltages of the display device, which can prompt the user to intervene in a timely manner, thereby avoiding the impact on the operation of the equipment due to abnormal voltage of the display device.

[0016] In some embodiments, the adjustment unit 11 includes a plurality of first adjustment circuits 111. The input terminal of each first adjustment circuit 111 is connected to the input / output terminal of the display driver chip or the power input / output terminal of the light source driver chip, and is used to acquire the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip, and adjust it to a set voltage by stepping down the voltage. The output terminal of the first adjustment circuit 111 is connected to the input terminal of the voltage comparison unit 12. Based on this design, the first adjustment circuit 111 performs step-down adjustment on the acquired input voltage / output voltage of the display driver chip 32 or the power input voltage / output voltage of the light source driver chip to adapt it to the input operating voltage of the voltage comparison unit 12.

[0017] Specifically, such as Figure 2 As shown, each of the first adjustment circuits 111 includes a first digitally adjustable resistor U1. The input terminal of the first digitally adjustable resistor U1 is connected to the input / output terminal of the display driver chip or the power input / output terminal of the light source driver chip. The output terminal of the first digitally adjustable resistor U1 is connected to the voltage comparison unit 12. The control terminal of the first digitally adjustable resistor U1 is used to receive a resistance adjustment signal. The first digitally adjustable resistor U1 can adjust its resistance value according to the resistance adjustment signal, thereby flexibly adjusting the voltage after the detected voltage (i.e., the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip) is stepped down. Understandably, in some other embodiments, the first adjustment circuit 111 can also be implemented by a fixed resistor voltage divider circuit, which is suitable for voltage reduction adjustment of a fixed voltage value. In other embodiments, the number of first adjustment circuits 111 can be one, and the number of first digital adjustable resistors U1 in the first adjustment circuit 111 can be multiple, so as to realize the detection of multiple abnormal voltages. Alternatively, if only the detection of one abnormal voltage is required, the number of first digital adjustable resistors U1 can also be set to one. That is, the number of first adjustment circuits 111 and first digital adjustable resistors U1 can be set according to actual needs.

[0018] In this invention, the number of voltage comparison units 12 is set according to the number of first adjustment circuits 111 or the number of first digital adjustable resistors U1. In this embodiment, multiple voltage comparison units 12 are provided corresponding to multiple first adjustment circuits 111. Figure 1 and Figure 4In some embodiments, the voltage comparison unit 12 includes a first voltage comparison circuit and a second voltage comparison circuit. The input terminal of the first voltage comparison circuit is connected to the output terminal of the first digitally adjustable resistor U1, and is used to compare whether the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is greater than their respective overvoltage reference voltages, and outputs an overvoltage signal when either voltage is greater than its overvoltage reference voltage. The input terminal of the second voltage comparison circuit is also connected to the output terminal of the first digitally adjustable resistor U1, and is used to compare whether the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is less than their respective undervoltage reference voltages, and outputs an undervoltage signal when either voltage is less than its undervoltage reference voltage. In this invention, the first voltage comparison circuit and the second voltage comparison circuit can be implemented by an operational amplifier. Preferably, a dual-channel operational amplifier U2 can be used to implement the functions of the first voltage comparison circuit and the second voltage comparison circuit, for example, as shown in the figure. Figure 4 As shown, a dual-channel operational amplifier of model SGM8745 is selected. Understandably, one input terminal of the first voltage comparator circuit and the second voltage comparator circuit (pins 6 and 3 of the dual-channel operational amplifier U2 of model SGM8745) are both connected to the output terminal of the first digital adjustable resistor U1, and the other input terminal (pins 5 and 2 of the dual-channel operational amplifier U2) receives the overvoltage reference voltage and the undervoltage reference voltage, respectively.

[0019] Furthermore, in this embodiment, the voltage detection circuit 10 further includes a reference adjustment circuit 14. The input and output terminals of the reference adjustment circuit 14 are respectively connected to the reference power supply VCC and the input terminal of the voltage comparison unit 12. It is used to adjust and match the reference voltages (i.e., overvoltage reference voltage and undervoltage reference voltage) at the overvoltage and undervoltage points of the voltage detection circuit 10, and transmit the reference voltages at the overvoltage and undervoltage points to the voltage comparison unit 12. Specifically, as... Figure 3As shown, the reference adjustment circuit 14 includes a second digitally adjustable resistor U5. The input terminal of the second digitally adjustable resistor U5 is connected to the reference power supply VCC, and the output terminal of the second digitally adjustable resistor U5 is connected to pins 5 and 2 of a dual-channel operational amplifier of model SGM8745 to provide overvoltage and undervoltage reference voltages to the voltage comparison unit 12, respectively. The control terminal of the second digitally adjustable resistor U5 can receive a resistance adjustment signal. The second digitally adjustable resistor U5 adjusts its resistance value according to the resistance adjustment signal, thereby adjusting the reference voltage value. Based on the above design, the overvoltage point and undervoltage point are matched by a resistor voltage divider, and the overvoltage point (i.e., the overvoltage reference voltage) and undervoltage point (i.e., the undervoltage reference voltage) can be adjusted according to actual needs. It is understood that in some other embodiments, the reference adjustment circuit 14 can also be implemented by a fixed resistor voltage divider circuit, which is suitable for step-down adjustment of a fixed reference voltage value.

[0020] like Figure 2 As shown, in this embodiment, the first digital adjustable resistor U1 can be a single-channel digital adjustable resistor of the AD5272 series. Its resistor R4 and the adjustable resistor form a resistor divider circuit to achieve adjustable resistance. Figure 3 As shown, the second digital adjustable resistor U5 can be a dual-channel digital adjustable resistor of the AD5272 series. Its resistor R2, together with the adjustable resistor and resistor R3, forms a resistor voltage divider circuit with two output terminals. The two output terminals output the overvoltage reference voltage H_LEVEL and the undervoltage reference voltage L_LEVEL, respectively.

[0021] In some embodiments, the voltage detection circuit 10 further includes an alarm circuit 13. The input terminal of the alarm circuit 13 is connected to the output terminal of the voltage comparison unit 12. The output terminal of the alarm circuit 13 serves as the output terminal of the voltage detection circuit 10 and can be connected to the MCU of the display device. It is used to output an abnormal alarm signal when the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is over-voltage / under-voltage.

[0022] Preferably, such as Figure 4 As shown, in this embodiment, the alarm circuit 13 is composed of logic gate circuits, including NAND gate U3. The two input terminals of NAND gate U3 receive overvoltage signals and undervoltage signals from the two output terminals of dual-channel operational amplifier U2, respectively. When the dual-channel operational amplifier U2 outputs low-level overvoltage signals and undervoltage signals, NAND gate U3 outputs a high-level abnormal alarm signal to the MCU of the display device, which can then display prompts through the display module, enabling the user to take corresponding risk avoidance actions.

[0023] When the voltage detection circuit 10 in this embodiment is working, the reference power supply VCC input is stepped down by the second digital adjustable resistor U5 and then outputs an overvoltage reference voltage H_LEVEL and an undervoltage reference voltage L_LEVEL to one input of the two comparators in the dual-channel operational amplifier U2. When the detected voltage VGH is input, it is stepped down by the first digital adjustable resistor U1 and outputs a stepped-down voltage VGH_IN to the other input of the two comparators in the dual-channel operational amplifier U2. If the stepped-down voltage VGH_IN is greater than the undervoltage reference voltage L_LEVEL and less than the overvoltage reference voltage H_LEVEL, then the detected voltage VGH is normal, and the dual-channel operation is complete. The operational amplifier U2 outputs high-level VGH_L and VGH_H to the NAND gate U3, and the NAND gate U3 outputs a low-level ERR signal to the display device's MCU. If the step-down voltage VGH_IN is less than the undervoltage reference voltage L_LEVEL or greater than the overvoltage reference voltage H_LEVEL, then the detected voltage VGH is undervoltage or overvoltage. The dual-channel operational amplifier U2 outputs low-level VGH_L and VGH_H to the NAND gate U3, and the NAND gate U3 outputs a high-level ERR signal to the display device's MCU, causing the MCU to drive the display module of the display device to provide an abnormal indication (the level signals are shown in Table 1 below). Table 1 In the table, the voltages under test 1, 2, 3, and 4 represent the input voltage, output voltage, power input voltage, and power output voltage of the display driver chip, respectively. H indicates the voltage under test is greater than its overvoltage reference voltage; L indicates it is less than its undervoltage reference voltage; O indicates it is less than its overvoltage reference voltage but greater than its undervoltage reference voltage; and X indicates the voltage under test is arbitrary, meaning it can be within the range of the undervoltage and overvoltage reference voltages, or greater than or less than the undervoltage reference voltage. It can be seen that when any voltage under test is greater than its overvoltage reference voltage or less than its undervoltage reference voltage, a high-level abnormal alarm signal is output to alert the user of a voltage abnormality.

[0024] Understandably, in some other embodiments, the voltage detection circuit 10 may further include a controller that implements the function of the alarm circuit 13, replacing the alarm circuit 13. One output terminal of the controller serves as the output terminal of the voltage detection circuit 10, and can be directly connected to the display module of the display device. This controller is used to provide a warning when overvoltage / undervoltage is detected in the input / output voltage of the LCD driver chip 32 or the power input / output voltage of the light source driver chip. Based on this design, the voltage detection circuit 10 can send an abnormal alarm signal to the MCU of the display device via the alarm circuit 13, so that the MCU processes the abnormal alarm signal and provides a warning through the display module. Alternatively, a separate controller can be configured within the voltage detection circuit 10 to generate and process an abnormal alarm signal when the voltage is abnormal, directly driving the display module to provide a warning. Furthermore, the controller can also receive resistance adjustment signals from external clients and transmit them to the first adjustment circuit 111 and the reference adjustment circuit 14.

[0025] Reference Figures 5 to 6 , Figures 5 to 6 A specific embodiment of the liquid crystal display device of this utility model is shown. In the embodiment shown in the accompanying drawings, the liquid crystal display device includes an LCD module 30, a backlight module 40, an MCU U4, and a voltage detection circuit 10. The LCD module 30 includes a liquid crystal display screen 31 and an LCD driver chip 32, the latter driving the liquid crystal display screen 31 to display images. The backlight module 40 includes a backlight display module 41 and a light source driver chip 42, the latter adjusting the brightness of the backlight display module 41 according to a dimming signal from the MCU U4. The input terminals of multiple first adjustment circuits 111 in the voltage detection circuit 10 are respectively connected to the input and output terminals of the LCD driver chip 32 and the power input and output terminals of the light source driver chip 42. The first adjustment circuits 111 and the voltage comparison unit 12 cooperate to detect whether the input and output voltages of the LCD driver chip 32 and the power input and output voltages of the light source driver chip 42 are over-voltage or under-voltage. If any voltage is over-voltage or under-voltage, the alarm circuit 13 in the voltage detection circuit 10 outputs an abnormal alarm signal to the MCU. When an abnormal voltage is detected, MCU U4 can also control the LCD display device to enter BIST (Built-In Self-Test) mode or OSD (On-Screen Display) mode via LCD driver chip 32. That is, MCU U4 judges the received abnormal alarm signal. When the abnormal alarm signal is high, it controls the LCD display device to enter BIST mode or OSD mode, thereby prompting the user that the voltage is abnormal.

[0026] In this embodiment, the resistance adjustment signal received by the first digitally adjustable resistor U1 in the first adjustment circuit 111 and the second digitally adjustable resistor U5 in the reference adjustment circuit 14 can be provided by the MCU U4 through the I2C interface. In some other embodiments, the resistance adjustment signal can be directly provided by an external client. It is understood that the voltage detection circuit of this invention can also be applied to other display devices, such as AMOLED and electronic paper.

[0027] It is understood that the liquid crystal display device of this utility model is provided with a voltage detection circuit 10, which can be used to detect whether the input voltage and output voltage of the LCD driver chip 32 and the power input voltage and output voltage of the light source driver chip 42 are over-voltage / under-voltage. Thus, when the liquid crystal display device is applied to a smart device, it can detect whether the voltage of the liquid crystal display device is abnormal in a timely manner, and prompt the user to intervene in a timely manner when the voltage is abnormal.

[0028] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Those skilled in the art can make various equivalent changes and improvements based on the above embodiments. All equivalent changes or modifications made within the scope of the claims should fall within the protection scope of the present utility model.

Claims

1. A voltage detection circuit, applied to a display device, characterized in that, The voltage detection circuit includes an adjustment unit and a voltage comparison unit, wherein... The input terminal of the adjustment unit is connected to the input terminal and / or output terminal of the display driver chip in the display device, and / or connected to the power input terminal and / or power output terminal of the light source driver chip in the display device, for obtaining the input voltage and / or output voltage of the display driver chip, and / or obtaining the power input voltage and / or output voltage of the light source driver chip, and adapting the obtained input voltage and / or output voltage to the operating voltage of the voltage comparison unit; The input terminal of the voltage comparison unit is connected to the output terminal of the adjustment unit, and is used to detect whether the input voltage and / or output voltage obtained by the adjustment unit is over-voltage or under-voltage. The output terminal of the voltage comparison unit serves as the output terminal of the voltage detection circuit.

2. The voltage detection circuit as described in claim 1, characterized in that, The adjustment unit includes at least one first adjustment circuit. The input terminal of the first adjustment circuit is connected to the input terminal and / or output terminal of the display driver chip, and / or connected to the power input terminal and / or power output terminal of the light source driver chip. It is used to obtain the input voltage and / or output voltage of the display driver chip, and / or obtain the power input voltage and / or output voltage of the light source driver chip, and perform voltage reduction adjustment to a set voltage. The output terminal of the first adjustment circuit is connected to the input terminal of the voltage comparison unit.

3. The voltage detection circuit as described in claim 2, characterized in that, The first adjustment circuit includes at least one first digital adjustable resistor. The input terminal of each first digital adjustable resistor is connected to the input / output terminal of the display driver chip or the power input / output terminal of the light source driver chip. The output terminal of the first digital adjustable resistor is connected to the voltage comparison unit. The control terminal of the first digital adjustable resistor is used to receive a resistance adjustment signal. The first digital adjustable resistor adjusts its internal resistance according to the resistance adjustment signal.

4. The voltage detection circuit as described in claim 3, characterized in that, The adjustment unit includes a first adjustment circuit, and the first adjustment circuit includes a plurality of the first digitally adjustable resistors; or The adjustment unit includes a plurality of the first adjustment circuits, each of the adjustment circuits including at least one first digitally adjustable resistor; or The adjustment unit includes a first adjustment circuit, and the adjustment circuit includes a first digitally adjustable resistor.

5. The voltage detection circuit as described in claim 1, characterized in that, The voltage detection circuit further includes a reference adjustment circuit. The input and output terminals of the reference adjustment circuit are respectively connected to a reference power supply and an input terminal of the voltage comparison unit. The reference adjustment circuit is used to adjust the reference voltage at the overvoltage and undervoltage points of the voltage detection circuit and transmit the reference voltage at the overvoltage and undervoltage points to the voltage comparison unit.

6. The voltage detection circuit as described in claim 5, characterized in that, The reference adjustment circuit includes a second digital adjustable resistor. The input and output terminals of the second digital adjustable resistor are respectively connected to the reference power supply and the voltage comparison unit. The control terminal of the second digital adjustable resistor is used to receive the resistance adjustment signal.

7. The voltage detection circuit as described in claim 1, characterized in that, The voltage comparison unit includes: The first voltage comparison circuit has its input terminal connected to the output terminal of the adjustment unit. It is used to compare whether the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is greater than the overvoltage reference voltage, and outputs an overvoltage signal when it is greater than the overvoltage reference voltage. The second voltage comparison circuit has its input terminal connected to the output terminal of the adjustment unit. It is used to compare whether the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is less than the undervoltage reference voltage, and outputs an undervoltage signal when it is less than the undervoltage reference voltage.

8. The voltage detection circuit as described in claim 1, characterized in that, The voltage detection circuit also includes an alarm circuit. The input terminal of the alarm circuit is connected to the output terminal of the voltage comparison unit. The output terminal of the alarm circuit serves as the output terminal of the voltage detection circuit and is used to output an abnormal alarm signal when the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is over-voltage / under-voltage.

9. The voltage detection circuit as described in any one of claims 1-7, characterized in that, The voltage detection circuit also includes a controller. The output terminal of the voltage comparison unit is connected to the controller. One output terminal of the controller serves as the output terminal of the voltage detection circuit and is connected to the display driver chip. This is used to provide a prompt when the input voltage / output voltage of the display driver chip or the power input voltage / output voltage of the light source driver chip is detected to be over-voltage / under-voltage.

10. A display device, characterized in that, It includes a display module, a light source module, an MCU, and the voltage detection circuit according to any one of claims 1-9, wherein, The display module includes a display screen and a display driver chip, wherein the display driver chip is used to drive the display screen to display images; The light source module includes a light source display module and a light source driver chip. The light source driver chip is used to adjust the brightness of the light source display module according to the dimming signal from the MCU. The input terminal of the voltage detection circuit is connected to the input terminal and / or output terminal of the display driver chip, and / or to the power input terminal and / or power output terminal of the light source driver chip, for detecting whether the input voltage / output voltage of the display driver chip and / or the power input voltage / output voltage of the light source driver chip are over-voltage / under-voltage.

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