An automatic backlight control circuit

Abstract

This utility model relates to an automatic backlight control circuit, which includes a hardware interface circuit, a power supply circuit, an LCD screen driving circuit, a backlight driving circuit, a heating driving circuit, and a sampling circuit. The backlight driving circuit employs a dual-mode night vision compatible backlight source: a white LED backlight is driven during the day, while a backup OGB (orange, green, and blue) LED is driven in night vision conditions, meeting display requirements in different environments. Simultaneously, the circuit features low-temperature heating and high-temperature thermal protection functions, automatically adjusting the backlight brightness according to ambient light intensity to ensure normal operation of the LCD display under harsh flight conditions. This utility model is applicable to airborne LCD displays and other display devices requiring highly reliable backlight control.

Description

Technical Field

[0001] This utility model relates to the field of backup display and LCD screen backlight control technology, and in particular to an automatic backlight control circuit. Background Technology

[0002] Liquid crystal display (LCD) modules are the terminal display components of monitors, widely used in various display devices, especially in the aviation field, where airborne LCDs need to display various graphic and textual information in real time under harsh flight conditions. However, existing backlight driving circuits have the following shortcomings:

[0003] Poor environmental adaptability: In low-temperature environments, the backlight brightness of the LCD monitor will decrease, affecting the display effect; in high-temperature environments, the backlight driving circuit is prone to overheating and damage.

[0004] Unintelligent brightness adjustment: It cannot automatically adjust the backlight brightness according to the ambient light intensity, resulting in excessive brightness in strong light and excessive darkness in weak light, affecting visibility.

[0005] Insufficient night vision compatibility: In night flight situations, when pilots wear low-light night vision goggles, the unprocessed light source will emit infrared and near-infrared light, which will interfere with the pilot's vision and affect flight safety.

[0006] Therefore, developing a backlight automatic control circuit that can adapt to harsh environments, has automatic brightness adjustment function, and is compatible with night vision systems is of great significance for improving the performance and safety of LCD displays. Utility Model Content

[0007] The purpose of this invention is to provide an automatic backlight control circuit, thereby solving the aforementioned problems existing in the prior art.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] An automatic backlight control circuit includes:

[0010] Hardware interface circuitry, used to meet the user's electrical interface requirements;

[0011] The power processing circuit, connected to the hardware interface circuit, is used to convert the input power into various power supplies required for the module to operate.

[0012] The LCD screen driving circuit, connected to the power supply processing circuit, is used to process the RGB signals input by the user and drive the LCD screen to achieve real-time display.

[0013] A backlight driving circuit, connected to a power supply processing circuit, includes:

[0014] Two white backlight driving circuits are used to provide white LED backlight during the day;

[0015] Three OGB backlight driver circuits are used to provide backup LED backlights in night vision situations to meet night vision compatibility requirements;

[0016] A heating drive circuit, connected to a power supply processing circuit, is used to heat the display screen under low-temperature conditions.

[0017] The sampling circuit, connected to the backlight driving circuit, heating driving circuit, and LCD screen driving circuit, is used to collect analog quantities, temperature data, and the working status of internal modules, and to complete the backlight adjustment and heating function control.

[0018] In some specific embodiments, the dual-path white light backlight driving circuit includes:

[0019] The backlight chip U3 controls the output of two adjustable white light sources through PIN1 and PIN28 respectively via the dimming signals W_PWM_1 and W_PWM_2.

[0020] The W_SHDN signal controls the operating state of the device enabled by PIN26;

[0021] The built-in gate driver drives the external P-channel MOSFET to generate the first LED backlight signal W11+ and W11-, and the second LED backlight signal W22+ and W22-. W11+, W11-, W22+, and W22- are output to the connector.

[0022] In some specific embodiments, the three-channel OGB backlight driving circuit includes:

[0023] The backlight chip U4 controls the output of three adjustable orange, green and blue light sources via PIN1, PIN28 and PIN27 respectively through O_PWM, G_PWM and B_PWM dimming signals;

[0024] The OGB_SHDN signal controls the operating state of the device via PIN26;

[0025] The built-in gate driver drives the external P-channel MOSFET to generate one orange LED backlight signal O11+ and O11-, one green LED backlight signal G11+ and G11-, and one blue LED backlight signal B11+ and B11-. O11+, O11-, G11+, G11-, B11+, and B11- are output to the connector.

[0026] In some specific embodiments, the heating drive circuit includes:

[0027] The HEAT_ITO signal is used to control the switching operation of optocoupler U14 via software discrete quantity control;

[0028] The U15 optocoupler circuit is connected to the HEAT_ITO signal and is used to control the HEAT_ACQ circuit in the heating state.

[0029] In some specific embodiments, the backlight driving circuit also includes a dual-mode night vision compatible backlight, which can switch between daytime and night vision conditions to ensure the visibility of the display content in different environments.

[0030] In some specific embodiments, the sampling circuit includes a temperature sensor and a brightness sensor:

[0031] A temperature sensor, connected to the heating drive circuit, is used to monitor the operating temperature of the display screen in real time.

[0032] A brightness sensor, connected to the backlight drive circuit, is used to monitor ambient light intensity in real time.

[0033] In some specific embodiments, the backlight automatic control circuit also includes a fault detection circuit, which is connected to the LCD screen driving circuit, the backlight driving circuit and the heating driving circuit, for detecting the working status of each functional module of the display component, and reporting the fault through the BIT signal when a fault is detected.

[0034] In some specific embodiments, the backlight automatic control circuit also includes a power monitoring unit connected to the power processing circuit, which is used to monitor the power status in real time and trigger a protection mechanism when the power is abnormal to ensure circuit safety.

[0035] In some specific embodiments, the backlight automatic control circuit also includes a heat dissipation unit connected to the backlight driving circuit and the heating driving circuit, used to dissipate heat from the circuit in a high-temperature environment and ensure the stable operation of the circuit.

[0036] The beneficial effects of this utility model are:

[0037] Highly adaptable to the environment:

[0038] Low-temperature heating function: In low-temperature environments, the heating drive circuit can be automatically activated to heat the display screen, ensuring that the LCD monitor can still work normally under low-temperature conditions and avoiding display delay or blurring problems caused by low temperatures.

[0039] High-temperature thermal protection function: It has a high-temperature protection mechanism. When the ambient temperature is too high, it can automatically trigger protection measures to prevent the backlight drive circuit from being damaged due to overheating and extend the service life of the circuit.

[0040] Intelligent brightness adjustment:

[0041] Automatic brightness adjustment function: The backlight brightness is automatically adjusted based on the ambient light intensity, using a brightness sensor in the sampling circuit. In bright light environments, the backlight brightness automatically increases to ensure the displayed content is clearly visible; in low light environments, the backlight brightness automatically decreases to avoid the screen being too bright and dazzling, while also reducing energy consumption.

[0042] Adaptable to different lighting conditions: It can automatically adapt to various lighting environments from low light to strong light, ensuring optimal visibility under any lighting conditions and enhancing the user's visual experience.

[0043] Night vision compatibility:

[0044] Dual-mode night vision compatible backlight: The backlight is designed for both daytime and night vision modes. During the day, a white LED backlight is used, providing high brightness and high contrast. In night vision mode, it switches to a backup OGB (orange, green, and blue) LED light. The spectral range of these colors does not conflict with the operating spectrum (630-940nm) of the low-light night vision device, avoiding interference with the pilot and ensuring flight safety.

[0045] In summary, the backlight automatic control circuit of this utility model, through innovative design and functional implementation, effectively solves the problems existing in the prior art, significantly improves the performance and reliability of LCD displays in harsh environments, and meets special requirements such as night vision compatibility, thus having broad application prospects and significant economic benefits. Attached Figure Description

[0046] Figure 1 This is a circuit block diagram of the backlight driver board of this utility model;

[0047] Figure 2 This is a schematic diagram of the white backlight driving circuit of this utility model;

[0048] Figure 3 This is a schematic diagram of the three-channel OGB backlight driving circuit of this utility model;

[0049] Figure 4 This is a schematic diagram of the screen heating circuit of this utility model. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0051] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4The backlight automatic control circuit shown includes:

[0052] Hardware interface circuitry, used to meet the user's electrical interface requirements;

[0053] The power processing circuit, connected to the hardware interface circuit, is used to convert the input power into various power supplies required for the module to operate.

[0054] The LCD screen driving circuit, connected to the power supply processing circuit, is used to process the RGB signals input by the user and drive the LCD screen to achieve real-time display.

[0055] A backlight driving circuit, connected to a power supply processing circuit, includes:

[0056] Two white backlight driving circuits are used to provide white LED backlight during the day;

[0057] Three OGB backlight driver circuits are used to provide backup LED backlights in night vision situations to meet night vision compatibility requirements;

[0058] A heating drive circuit, connected to a power supply processing circuit, is used to heat the display screen under low-temperature conditions.

[0059] The sampling circuit, connected to the backlight driving circuit, heating driving circuit, and LCD screen driving circuit, is used to collect analog quantities, temperature data, and the working status of internal modules, and to complete the backlight adjustment and heating function control.

[0060] 1. Hardware interface circuit

[0061] The hardware interface circuit serves as the bridge connecting the entire backlight automatic control circuit to external devices. Its main function is to meet the user's electrical interface requirements, ensuring a stable and reliable connection between the circuit and external power supplies, control signals, and other related equipment. Through the hardware interface circuit, external power signals, control commands, and other necessary signals can be received. Simultaneously, internal status information and fault signals can be output to external devices, enabling interaction and collaborative operation with external systems.

[0062] 2. Power supply processing circuit

[0063] The power processing circuit connects to the hardware interface circuit, and its core function is to convert the externally input power into various power supplies required for the module's operation. In practical applications, the input power may come from different power supply devices with different voltage, current, and other parameters. The power processing circuit, through a series of power conversion, voltage regulation, and filtering operations, converts the input power into a stable power supply suitable for the normal operation of various modules such as the backlight drive circuit, LCD screen drive circuit, and heating drive circuit. For example, it converts a higher voltage input power supply into a constant current source suitable for the backlight drive circuit, or a lower voltage input power supply suitable for the LCD screen drive circuit. Through the precise control and conversion of the power processing circuit, the entire backlight automatic control circuit can operate stably and efficiently, while avoiding circuit failures or performance degradation caused by power supply issues.

[0064] 3. LCD screen driving circuit

[0065] The LCD screen driver circuit is connected to the power supply processing circuit. Its main function is to process the RGB signals input by the user and drive the LCD screen to achieve real-time display. In an LCD monitor, the RGB signal is the key signal that determines the displayed content, containing information such as the image's color and brightness. The LCD screen driver circuit receives a stable power supply after conversion by the power supply processing circuit, processes and amplifies the input RGB signal, and then transmits the processed signal to the LCD screen to control the pixels on the screen to emit light, thereby realizing the image display. Through precise signal processing and drive control, the LCD screen driver circuit can ensure the clarity, color accuracy, and dynamic performance of the displayed image, meeting the user's demand for high-quality display.

[0066] 4. Backlight driving circuit

[0067] The backlight driver circuit, connected to the power supply circuit, is one of the core components of the entire automatic backlight control circuit. Its main function is to provide the necessary backlight source for the LCD screen and automatically adjust the brightness and color of the backlight according to different usage environments and needs. The backlight driver circuit includes two white backlight driver circuits and three OGB backlight driver circuits.

[0068] 4.1 Dual-channel white backlight driving circuit

[0069] The dual-channel white LED backlight driver circuit is primarily used to provide a white LED backlight during the day. Under daytime or normal lighting conditions, the white LED backlight provides high brightness and high contrast, ensuring clear image display even in bright environments. This circuit is implemented through backlight chip U3, which controls PIN1 and PIN28 to output two adjustable white light sources via dimming signals W_PWM_1 and W_PWM_2 respectively. The W_SHDN signal controls the enabling device's operating state at PIN26. An internal gate driver drives an external P-channel MOSFET to generate the first LED backlight signal W11+ and W11-, and the second LED backlight signal W22+ and W22-. These signals are output to the connector, ultimately driving the white LED backlight to emit light. Through precise dimming control and stable current output, the dual-channel white LED backlight driver circuit can adjust the backlight brightness according to actual needs, achieving energy saving and optimized display effects.

[0070] 4.2 Three-channel OGB backlight driver circuit

[0071] The three-channel OGB backlight driver circuit is primarily used to provide backup LED backlights for night vision applications, ensuring compatibility with night vision requirements. During night flight or in low-light conditions, to ensure pilots can clearly see the display content while wearing low-light night vision goggles, and to avoid interfering with their operation, the backlight driver circuit switches to OGB (orange, green, and blue) backlights. Backlight chip U4 controls the output of three adjustable orange, green, and blue light sources via O_PWM, G_PWM, and B_PWM dimming signals through PIN1, PIN28, and PIN27 respectively. The OGB_SHDN signal controls the enabling device's operating state at PIN26. An internal gate driver drives an external P-channel MOSFET to generate one orange LED backlight signal (O11+ and O11-), one green LED backlight signal (G11+ and G11-), and one blue LED backlight signal (B11+ and B11-). These signals are output to the connector to drive the OGB LED backlights. The OGB backlight's color selection and brightness adjustment effectively avoid interference with low-light night vision devices, ensuring that the display content is clearly visible under night vision conditions, thus meeting the special needs of the aviation industry.

[0072] 5. Heating drive circuit

[0073] The heating drive circuit is connected to the power supply circuit, and its main function is to heat the display screen under low-temperature conditions. In low-temperature environments, the performance of the LCD can be affected, such as slower response times and reduced backlight brightness, thus impacting display quality. The heating drive circuit is controlled by the HEAT_ITO signal, which controls the switching operation of optocoupler U14 via software discrete control. Simultaneously, optocoupler circuit U15 controls the heating state of the HEAT_ACQ loop. When the ambient temperature is detected to be below a set threshold, the heating drive circuit automatically starts to heat the display screen, ensuring that the LCD can still operate normally under low-temperature conditions and avoiding display delays or blurring caused by low temperatures. Through precise temperature control and heating management, the heating drive circuit can maintain display performance while avoiding increased energy consumption and equipment damage due to overheating.

[0074] 6. Sampling Circuit

[0075] The sampling circuit is connected to the backlight drive circuit, heating drive circuit, and LCD screen drive circuit. Its main function is to collect analog signals, temperature data, and the operating status of internal modules, and to control the backlight adjustment and heating functions. The sampling circuit monitors ambient light intensity, the display's operating temperature, and the operating status of each module in real time through a series of sensors and detection circuits. For example, a brightness sensor monitors ambient light intensity, and a temperature sensor monitors the display's operating temperature. The sampling circuit transmits the collected data to the control unit, which automatically adjusts the backlight brightness and heating function based on this data. For example, in a bright light environment, the control unit increases the backlight brightness based on the data collected by the brightness sensor; in a low-temperature environment, the control unit activates the heating function based on the data collected by the temperature sensor. Through the real-time monitoring and feedback control of the sampling circuit, the automatic backlight control circuit can achieve intelligent backlight adjustment and heating management, ensuring optimal display effects and device performance under different environmental conditions.

[0076] In some specific embodiments, the dual-path white light backlight driving circuit includes:

[0077] The backlight chip U3 controls the output of two adjustable white light sources through PIN1 and PIN28 respectively via the dimming signals W_PWM_1 and W_PWM_2.

[0078] The W_SHDN signal controls the operating state of the device enabled by PIN26;

[0079] The built-in gate driver drives the external P-channel MOSFET to generate the first LED backlight signal W11+ and W11-, and the second LED backlight signal W22+ and W22-. W11+, W11-, W22+, and W22- are output to the connector.

[0080] Two-way white light backlight driving circuit

[0081] 1. Backlight chip U3

[0082] The backlight chip U3 is the core component of the dual-channel white light backlight driver circuit. It is a dedicated constant current source driver specifically designed to drive LED backlights. This chip receives external control signals and precisely controls the output current, thereby adjusting the brightness of the LEDs.

[0083] 2. Dimming signal control

[0084] The backlight chip U3 controls its two internal output pins (PIN1 and PIN28) through two dimming signals (W_PWM_1 and W_PWM_2). These two dimming signals are pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signals, precise control of the output current can be achieved, thereby adjusting the brightness of the white LED backlight.

[0085] W_PWM_1: Controls the current output of PIN1, used to drive the first white LED backlight.

[0086] W_PWM_2: Controls the current output from PIN28, used to drive the second white LED backlight.

[0087] 3. Device enable control

[0088] The operating state of the backlight chip U3 is controlled by the W_SHDN signal. This signal is connected to pin PIN26 of the chip and is used to enable or disable the entire driver chip. When the W_SHDN signal is low, the chip is enabled and can operate normally; when the W_SHDN signal is high, the chip is disabled, stops outputting current, and thus turns off the LED backlight. This enable control mechanism can effectively reduce power consumption and shut down the circuit when backlighting is not needed, extending the lifespan of the device.

[0089] 4. Built-in gate driver

[0090] The backlight chip U3 integrates a gate driver to drive the external P-channel MOSFET. The gate driver's function is to provide sufficient drive current and voltage to ensure that the MOSFET can be turned on and off quickly and stably.

[0091] First LED backlight signal:

[0092] PIN17, PIN18, and PIN19: Drive the external P-channel MOSFET through the built-in gate driver to generate the first LED backlight signals W11+ and W11-.

[0093] W11+ and W11-: These two signals serve as the positive and negative outputs of the first LED backlight, respectively, and are connected to an external white LED.

[0094] Second LED backlight signal:

[0095] PIN13, PIN14, PIN15: Drive the external P-channel MOSFET through the built-in gate driver to generate the second LED backlight signals W22+ and W22-.

[0096] W22+ and W22-: These two signals serve as the positive and negative outputs of the second LED backlight, respectively, and are connected to an external white LED.

[0097] 5. Output to connector

[0098] The four backlight signals, W11+, W11-, W22+, and W22-, are ultimately output to the connector. The connector's function is to transmit these signals to the external LED backlight module. Through the connector, the backlight driver circuit can be easily connected to the external LED light group to achieve the backlight function.

[0099] Working principle: Dimming control:

[0100] When the system needs to adjust the backlight brightness, the backlight chip U3 adjusts the current output of PIN1 and PIN28 according to the duty cycle of the W_PWM_1 and W_PWM_2 signals.

[0101] For example, when the duty cycle of W_PWM_1 increases, the current output by PIN1 increases, and the brightness of the first white LED backlight also increases; conversely, when the duty cycle decreases, the brightness decreases.

[0102] Enable control:

[0103] When the system needs to turn off the backlight, the W_SHDN signal is set to a high level, the backlight chip U3 stops working, and the current output of all output pins (including PIN1 and PIN28) is disabled, thereby turning off all LED backlights.

[0104] When the backlight needs to be turned on, the W_SHDN signal is set to low level, the backlight chip U3 is enabled and starts to work normally, and the output current drives the LED backlight to emit light.

[0105] Drive MOSFET:

[0106] The built-in gate driver outputs drive signals through pins PIN17, PIN18, PIN19 and PIN13, PIN14, PIN15 to control the turn-on and turn-off of the external P-channel MOSFET.

[0107] When the MOSFET is turned on, current flows through the LED, causing it to emit light; when the MOSFET is turned off, the LED turns off. By precisely controlling the MOSFET's on-time, the brightness of the LED can be adjusted.

[0108] Signal output:

[0109] The W11+ and W11- signals are connected to the positive and negative terminals of the first LED backlight, and the W22+ and W22- signals are connected to the positive and negative terminals of the second LED backlight.

[0110] These signals are transmitted to the external LED light group through the connector to ensure that the backlight signal can stably and reliably drive the LED backlight to emit light.

[0111] Through the above design, the two white backlight driving circuits can achieve precise brightness adjustment, flexible enable control, and stable backlight driving function, meeting the needs of daytime display while providing an efficient and reliable backlight solution for the entire backlight automatic control circuit.

[0112] In some specific embodiments, the three-channel OGB backlight driving circuit includes:

[0113] The backlight chip U4 controls the output of three adjustable orange, green and blue light sources via PIN1, PIN28 and PIN27 respectively through O_PWM, G_PWM and B_PWM dimming signals;

[0114] The OGB_SHDN signal controls the operating state of the device via PIN26;

[0115] The built-in gate driver drives the external P-channel MOSFET to generate one orange LED backlight signal O11+ and O11-, one green LED backlight signal G11+ and G11-, and one blue LED backlight signal B11+ and B11-. O11+, O11-, G11+, G11-, B11+, and B11- are output to the connector.

[0116] Three-channel OGB backlight driver circuit

[0117] 1. Backlight chip U4

[0118] The backlight chip U4 is the core component of the three-channel OGB backlight driver circuit. It is a dedicated constant current source driver specifically designed to drive LED backlights. This chip can precisely control the output current based on the input dimming signal, thereby adjusting the brightness and color of the LEDs.

[0119] 2. Dimming signal control

[0120] The backlight chip U4 controls its three internal output pins (PIN1, PIN28, PIN27) through three dimming signals (O_PWM, G_PWM, B_PWM) to adjust the brightness of three different colored LED light sources.

[0121] O_PWM: Controls the current output of PIN1, used to drive the orange LED backlight.

[0122] G_PWM: Controls the current output from PIN28, used to drive the green LED backlight.

[0123] B_PWM: Controls the current output from PIN27, used to drive the blue LED backlight.

[0124] These dimming signals are pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signal, precise control of the output current can be achieved, thereby adjusting the brightness of the corresponding color LED backlight.

[0125] 3. Device enable control

[0126] The operating state of the backlight chip U4 is controlled by the OGB_SHDN signal. This signal is connected to pin PIN26 of the chip and is used to enable or disable the entire driver chip. When the OGB_SHDN signal is low, the chip is enabled and can operate normally; when the OGB_SHDN signal is high, the chip is disabled, stops outputting current, and thus turns off all LED backlights. This enable control mechanism can effectively reduce power consumption and shut down the circuit when backlighting is not needed, extending the lifespan of the device.

[0127] 4. Built-in gate driver

[0128] The backlight chip U4 integrates a gate driver to drive the external P-channel MOSFET. The gate driver's function is to provide sufficient drive current and voltage to ensure that the MOSFET can be turned on and off quickly and stably.

[0129] Orange LED backlight signal:

[0130] PIN22, PIN23, PIN24: Drive an external P-channel MOSFET through a built-in gate driver to generate an orange LED backlight signal O11+ and O11-.

[0131] O11+ and O11-: These two signals are used as the positive and negative outputs of the orange LED backlight, respectively, and are connected to the external orange LED light.

[0132] Green LED backlight signal:

[0133] PIN17, PIN18, PIN19: Drive an external P-channel MOSFET through the built-in gate driver to generate a green LED backlight signal G11+ and G11-.

[0134] G11+ and G11-: These two signals are used as the positive and negative outputs of the green LED backlight, respectively, and are connected to the external green LED light.

[0135] Blue LED backlight signal:

[0136] PIN13, PIN14, PIN15: Drive an external P-channel MOSFET through the built-in gate driver to generate a blue LED backlight signal B11+ and B11-.

[0137] B11+ and B11-: These two signals are used as the positive and negative outputs of the blue LED backlight, respectively, and are connected to the external blue LED light.

[0138] 5. Output to connector

[0139] The six backlight signals, O11+, O11-, G11+, G11-, B11+, and B11-, are ultimately output to the connector. The connector's function is to transmit these signals to the external LED backlight module. Through the connector, the backlight driver circuit can be easily connected to the external LED light group to achieve the backlight function.

[0140] Working principle

[0141] Dimming control:

[0142] When the system needs to adjust the backlight brightness, the backlight chip U4 adjusts the current output of PIN1, PIN28 and PIN27 according to the duty cycle of the O_PWM, G_PWM and B_PWM signals.

[0143] For example, when the duty cycle of O_PWM increases, the current output by PIN1 increases, and the brightness of the orange LED backlight also increases; conversely, when the duty cycle decreases, the brightness decreases. The brightness adjustment principle for the green and blue LED backlights is the same.

[0144] Enable control:

[0145] When the system needs to turn off the backlight, the OGB_SHDN signal is set to a high level, the backlight chip U4 stops working, and the current output of all output pins (including PIN1, PIN28 and PIN27) is disabled, thereby turning off all LED backlights.

[0146] When the backlight needs to be turned on, the OGB_SHDN signal is set to low level, the backlight chip U4 is enabled and starts to work normally, and the output current drives the LED backlight to emit light.

[0147] Drive MOSFET:

[0148] The built-in gate driver outputs drive signals through pins PIN22, PIN23, PIN24, PIN17, PIN18, PIN19, PIN13, PIN14, and PIN15 to control the on and off states of the external P-channel MOSFET.

[0149] When the MOSFET is turned on, current flows through the LED, causing it to emit light; when the MOSFET is turned off, the LED turns off. By precisely controlling the MOSFET's on-time, the brightness of the LED can be adjusted.

[0150] Signal output:

[0151] The O11+ and O11- signals are connected to the positive and negative terminals of the orange LED backlight, the G11+ and G11- signals are connected to the positive and negative terminals of the green LED backlight, and the B11+ and B11- signals are connected to the positive and negative terminals of the blue LED backlight.

[0152] These signals are transmitted to the external LED light group through the connector to ensure that the backlight signal can stably and reliably drive the LED backlight to emit light.

[0153] Night vision compatibility

[0154] The design of the three-channel OGB backlight driver circuit takes night vision compatibility into account. In night flight or low-light environments, when pilots wear low-light night vision goggles, untreated light sources emit infrared and near-infrared light, interfering with their vision. By using orange, green, and blue LED backlights, the spectral range of these colors does not conflict with the operating spectrum (630-940nm) of low-light night vision goggles, thus avoiding interference with the pilot and ensuring flight safety.

[0155] Through the above design, the three-channel OGB backlight driver circuit can achieve precise brightness adjustment, flexible enable control, and stable backlight driving function, meeting the requirements of night vision compatibility while providing an efficient and reliable backlight solution for the entire backlight automatic control circuit.

[0156] In some specific embodiments, the heating drive circuit includes:

[0157] The HEAT_ITO signal is used to control the switching operation of optocoupler U14 via software discrete quantity control;

[0158] The U15 optocoupler circuit is connected to the HEAT_ITO signal and is used to control the HEAT_ACQ circuit in the heating state.

[0159] 1. HEAT_ITO signal and optocoupler U14

[0160] HEAT_ITO signal: This is a software discrete control signal used to control the switching operation of the heating drive circuit. Through discrete signals generated by software logic, HEAT_ITO can precisely control the start and stop of the heating circuit.

[0161] Optocoupler U14: Optocoupler U14 is an optocoupler used for signal isolation and transmission. The HEAT_ITO signal is isolated through optocoupler U14 to ensure the stability and safety of the control signal. When the HEAT_ITO signal is high, optocoupler U14 is turned on, triggering the heating circuit; when the signal is low, optocoupler U14 is turned off, and the heating circuit is turned off.

[0162] 2. U15 optocoupler circuit and HEAT_ACQ loop

[0163] U15 Optocoupler Circuit: The U15 optocoupler circuit is connected to the HEAT_ITO signal and is used to monitor the heating status. It detects the operating status of the heating circuit through optocoupler and feeds the status information back to the control system.

[0164] HEAT_ACQ loop: This is a heating status feedback loop used to monitor the heating circuit's normal operation in real time. When the heating circuit starts, the HEAT_ACQ loop detects the heating signal and transmits the status information to the control system via the U15 optocoupler, ensuring the reliability and safety of the heating process.

[0165] In some specific embodiments, the backlight driving circuit also includes a dual-mode night vision compatible backlight, which can switch between daytime and night vision conditions to ensure the visibility of the display content in different environments.

[0166] 1. Daytime mode

[0167] During daytime or under normal lighting conditions, the backlight driving circuit switches to a white LED backlight. The white LED backlight provides high brightness and high contrast, ensuring that the LCD screen can clearly display images even in bright environments.

[0168] 2. Night Vision Mode

[0169] In night flight or low-light environments, the backlight drive circuit switches to a backup OGB (orange, green, and blue) LED backlight. The spectral range of these colors does not conflict with the operating spectrum (630-940nm) of the low-light night vision device, avoiding interference with the pilot and ensuring flight safety. Through the dual-mode backlight design, the display content remains clearly visible in both daytime and nighttime conditions, meeting visibility requirements in different environments.

[0170] In some specific embodiments, the sampling circuit includes a temperature sensor and a brightness sensor:

[0171] A temperature sensor, connected to the heating drive circuit, is used to monitor the operating temperature of the display screen in real time.

[0172] A brightness sensor, connected to the backlight drive circuit, is used to monitor ambient light intensity in real time.

[0173] 1. Temperature sensor

[0174] Connection relationship: The temperature sensor is connected to the heating drive circuit.

[0175] Function Description: The temperature sensor is used to monitor the operating temperature of the display screen in real time. It converts temperature information into an electrical signal and transmits it to the control system. The control system automatically adjusts the operating status of the heating circuit based on the temperature data, ensuring that the display screen can operate normally in low-temperature environments while preventing equipment damage due to excessive heat.

[0176] 2. Brightness sensor

[0177] Connection relationship: The brightness sensor is connected to the backlight driving circuit.

[0178] Function Description: The brightness sensor monitors ambient light intensity in real time. It converts light intensity information into electrical signals and transmits them to the control system. The control system automatically adjusts the backlight brightness based on the light intensity data, ensuring that the displayed content is clearly visible in bright light environments and soft and non-glaring in low light environments, thereby improving the visibility of the display screen under different lighting conditions.

[0179] In some specific embodiments, the backlight automatic control circuit also includes a fault detection circuit, which is connected to the LCD screen driving circuit, the backlight driving circuit and the heating driving circuit, for detecting the working status of each functional module of the display component, and reporting the fault through the BIT signal when a fault is detected.

[0180] The fault detection circuit is used to detect the operating status of each functional module of the display component. It monitors parameters such as current and voltage in the circuit to determine in real time whether each module is functioning correctly. When a fault is detected, the fault detection circuit reports the fault information via a BIT signal, notifying maintenance personnel to handle the issue promptly and ensuring the stable operation of the system.

[0181] In some specific embodiments, the backlight automatic control circuit also includes a power monitoring unit connected to the power processing circuit, which is used to monitor the power status in real time and trigger a protection mechanism when the power is abnormal to ensure circuit safety.

[0182] The power monitoring unit is used to monitor the power supply status in real time. It can detect parameters such as voltage and current to ensure the stability and reliability of the power supply. When the power supply is abnormal (such as excessively high or low voltage or excessive current), the power monitoring unit will trigger the protection mechanism, cut off the power supply or enter protection mode to prevent the circuit from being damaged due to power problems and ensure the safe operation of the entire backlight automatic control circuit.

[0183] In some specific embodiments, the backlight automatic control circuit also includes a heat dissipation unit connected to the backlight driving circuit and the heating driving circuit, used to dissipate heat from the circuit in a high-temperature environment and ensure the stable operation of the circuit.

[0184] A heat dissipation unit is used to cool circuits in high-temperature environments. It dissipates heat generated during circuit operation through heat sinks, fans, or other cooling devices, ensuring stable operation even at high temperatures. The design of the heat dissipation unit effectively reduces circuit temperature, extends equipment lifespan, and improves system reliability.

[0185] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0186] like Figure 1 As shown, the backlight driver board is mainly divided into six parts: hardware interface circuit, power processing circuit, control circuit, LCD screen driver circuit, backlight driver circuit, heating driver circuit, and sampling circuit. The backlight driver board design must meet the user's electrical interface and power requirements, including adapting to the user's power consumption and characteristic requirements, converting it into various power supplies required for module operation; processing the RGB signals input by the user to drive the LCD screen for real-time display; collecting analog signals, temperature data, and internal module operating status to complete backlight adjustment and low-temperature display heating functions; and detecting various functions of the display components and driving the BIT signal to report faults. Simultaneously, a dual-mode night vision compatible backlight is designed, driving a white LED backlight during the day and a backup LED light in night vision conditions. This light is an OGB (orange, green, and blue) design, ensuring clear visibility of the display content under both night vision and naked-eye conditions.

[0187] like Figure 2 As shown, the design of the two-channel white backlight driving circuit is as follows:

[0188] The backlight chip U3 is a dedicated constant current source driver. The W_PWM_1 and W_PWM_2 dimming signals control PIN1 and PIN28 respectively to output two adjustable white light sources. The W_SHDN signal controls the enabling state of PIN26. PIN17, PIN18, and PIN19 drive an external P-channel MOSFET through an internal gate driver to generate the first LED backlight signal W11+ and W11-. PIN13, PIN14, and PIN15 drive an external P-channel MOSFET through an internal gate driver to generate the second LED backlight signal W22+ and W22-. W11+, W11-, W22+, and W22- are output to the connector.

[0189] like Figure 3 As shown, the design of the three-channel OGB backlight driver circuit is as follows:

[0190] The backlight chip U4 is a dedicated constant current source driver. The O_PWM, G_PWM, and B_PWM dimming signals control PIN1, PIN28, and PIN27 to output three adjustable orange, green, and blue light sources respectively. The OGB_SHDN signal controls the enabling state of PIN26. PIN22, PIN23, and PIN24 drive an external P-channel MOSFET through an internal gate driver to generate one orange LED backlight signal (O11+ and O11-). PIN17, PIN18, and PIN19 drive an external P-channel MOSFET through an internal gate driver to generate one green LED backlight signal (G11+ and G11-). PIN13, PIN14, and PIN15 drive an external P-channel MOSFET through an internal gate driver to generate a second blue LED backlight signal (B11+ and B11-). The remaining circuitry is configured according to the intended use. O11+, O11-, G11+, G11-, B11+, and B11- are output to the connector.

[0191] like Figure 4 As shown, the screen heating circuit design is as follows:

[0192] HEAT_ITO is a software discrete control optocoupler U14 that performs switching operations, while the HEAT_ACQ loop of the heating state is controlled by optocoupler circuit U15.

[0193] The present invention has been described in detail above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

[0194] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0195] 1. Strong environmental adaptability

[0196] Low-temperature heating function: Through the heating drive circuit, the heating function can be automatically activated in low-temperature environments to ensure that the LCD screen can still work normally under low-temperature conditions and avoid display delay or blurring problems caused by low temperature.

[0197] High-temperature thermal protection function: The power monitoring unit can monitor the power status in real time and trigger the protection mechanism when the power is abnormal or the temperature is too high, to prevent the backlight drive circuit from being damaged due to overheating and extend the service life of the circuit.

[0198] 2. Intelligent brightness adjustment

[0199] Automatic brightness adjustment function: The brightness sensor in the sampling circuit can monitor the ambient light intensity in real time and automatically adjust the backlight brightness according to the light intensity. In strong light environment, the backlight brightness is automatically increased to ensure that the displayed content is clearly visible; in low light environment, the backlight brightness is automatically reduced to avoid the screen being too bright and dazzling, while also reducing energy consumption.

[0200] Adaptable to different lighting conditions: It can automatically adapt to various lighting environments from low light to strong light, ensuring optimal visibility under any lighting conditions and enhancing the user's visual experience.

[0201] 3. Night vision compatibility

[0202] Dual-mode night vision compatible backlight: The backlight is designed for both daytime and night vision modes. During the day, a white LED backlight is used, providing high brightness and high contrast. In night vision mode, it switches to a backup OGB (orange, green, and blue) LED light. The spectral range of these colors does not conflict with the operating spectrum (630-940nm) of the low-light night vision device, avoiding interference with the pilot and ensuring flight safety.

[0203] Meeting night flight requirements: In night flight environments, when pilots wear low-light night vision goggles, the content on the display screen remains clearly visible and will not interfere with the pilot's vision, effectively improving the display effect and flight safety during night flights.

[0204] 4. High reliability

[0205] Fault detection and alarm: The fault detection circuit can monitor the working status of each functional module of the display component in real time, and report it through the BIT signal when a fault is detected, so as to facilitate timely discovery and handling of problems and ensure the stable operation of the system.

[0206] Power monitoring and protection: The power monitoring unit can monitor the power status in real time and trigger the protection mechanism when the power is abnormal to prevent circuit damage caused by power problems, thereby further improving the reliability of the system.

[0207] 5. Energy saving and high efficiency

[0208] Intelligent power management: The power processing circuit can dynamically adjust the power output according to actual needs, avoiding unnecessary energy consumption. It automatically reduces power consumption during low-brightness periods, achieving energy savings.

[0209] Optimized circuit design: Through efficient hardware interface circuits and optimized backlight drive circuit design, the circuit is designed to have a high energy efficiency ratio during operation, thereby reducing overall energy consumption.

[0210] 6. Easy to integrate and expand

[0211] Standardized interface design: The hardware interface circuit adopts a standardized design, which can be easily integrated with existing display devices and systems without complicated adaptation work.

[0212] Scalability: The circuit design has good scalability and can be expanded in terms of functionality according to different application scenarios and needs, such as adding more backlight modes or integrating with other intelligent display systems.

[0213] 7. Real-time monitoring and feedback

[0214] Temperature monitoring: The temperature sensor in the sampling circuit can monitor the operating temperature of the display screen in real time and feed the data back to the control system to ensure precise control of the heating function.

[0215] Brightness monitoring: The brightness sensor can monitor the ambient light intensity in real time and feed the data back to the control system to realize automatic adjustment of the backlight brightness.

[0216] 8. Heat dissipation management

[0217] Heat dissipation unit: Connected to the backlight drive circuit and heating drive circuit, the heat dissipation unit can dissipate heat from the circuits in high-temperature environments, ensuring stable operation. Effective heat dissipation management extends the lifespan of the equipment and improves system reliability.

[0218] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A backlight automatic control circuit, characterized by comprising: include: Hardware interface circuitry, used to meet the user's electrical interface requirements; The power processing circuit, connected to the hardware interface circuit, is used to convert the input power into various power supplies required for the module to operate. The LCD screen driving circuit, connected to the power supply processing circuit, is used to process the RGB signals input by the user and drive the LCD screen to achieve real-time display. A backlight driving circuit, connected to a power supply processing circuit, includes: Two white backlight driving circuits are used to provide white LED backlight during the day; Three-channel OGB backlight driver circuits are used to provide backup LED backlights in night vision situations to meet night vision compatibility requirements; A heating drive circuit, connected to a power supply processing circuit, is used to heat the display screen under low-temperature conditions. The sampling circuit, connected to the backlight driving circuit, heating driving circuit, and LCD screen driving circuit, is used to collect analog quantities, temperature data, and the working status of internal modules, and to complete the backlight adjustment and heating function control.

2. The automatic backlight control circuit according to claim 1, wherein The two-channel white light backlight driving circuit includes: The backlight chip U3 controls the output of two adjustable white light sources through PIN1 and PIN28 respectively via the dimming signals W_PWM_1 and W_PWM_2. The W_SHDN signal controls the operating state of the device enabled by PIN26; The built-in gate driver drives the external P-channel MOSFET to generate the first LED backlight signal W11+ and W11-, and the second LED backlight signal W22+ and W22-, which are output to the connector.

3. The automatic backlight control circuit of claim 1, wherein The three-channel OGB backlight driving circuit includes: The backlight chip U4 controls the output of three adjustable orange, green and blue light sources via PIN1, PIN28 and PIN27 respectively through O_PWM, G_PWM and B_PWM dimming signals; The OGB_SHDN signal controls the operating state of the device via PIN26; The built-in gate driver drives the external P-channel MOSFET to generate one orange LED backlight signal O11+ and O11-, one green LED backlight signal G11+ and G11-, and one blue LED backlight signal B11+ and B11-. The O11+, O11-, G11+, G11-, B11+, and B11- signals are output to the connector.

4. The automatic backlight control circuit of claim 1, wherein, The heating drive circuit includes: The HEAT_ITO signal is used to control the switching operation of optocoupler U14 via software discrete quantity control; The U15 optocoupler circuit is connected to the HEAT_ITO signal and is used to control the HEAT_ACQ circuit in the heating state.

5. The backlight automatic control circuit according to claim 1, characterized in that, The backlight driving circuit also includes a dual-mode night vision compatible backlight, which can switch between daytime and night vision conditions to ensure the visibility of the display content in different environments.

6. The automatic backlight control circuit of claim 1, wherein, The sampling circuit includes a temperature sensor and a brightness sensor: A temperature sensor, connected to the heating drive circuit, is used to monitor the operating temperature of the display screen in real time. A brightness sensor, connected to the backlight drive circuit, is used to monitor ambient light intensity in real time.

7. The automatic backlight control circuit of claim 1, wherein, The backlight automatic control circuit also includes a fault detection circuit, which is connected to the LCD screen driving circuit, the backlight driving circuit and the heating driving circuit. It is used to detect the working status of each functional module of the display component and report it through the BIT signal when a fault is detected.

8. The automatic backlight control circuit of claim 1, wherein, The backlight automatic control circuit also includes a power monitoring unit connected to the power processing circuit, which is used to monitor the power status in real time and trigger a protection mechanism when the power is abnormal to ensure circuit safety.

9. The automatic backlight control circuit of claim 1, wherein, The backlight automatic control circuit also includes a heat dissipation unit connected to the backlight driving circuit and the heating driving circuit, which is used to dissipate heat from the circuit in a high-temperature environment to ensure the stable operation of the circuit.

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