Digital dimming device and method for cockpit equipment

Abstract

The invention discloses a digital dimming device for cockpit equipment. The digital dimming device comprises a main control module and a signal acquisition module which are in electric signal connection, the system is characterized in that the system further comprises a hybrid dimming drive circuit connected between the main control module and the lighting device, and dimming model data are stored in the main control module; and the main control module is used for determining a target brightness duty ratio according to an input signal of the signal acquisition module and dimming model data, and adaptively dimming according to different conditions. When the target brightness is lower than the preset duty ratio threshold value, the PWM duty ratio is forcibly locked to be a fixed value, it is guaranteed that the switching tube has enough conduction time, and the brightness is reduced by reducing the amplitude of the driving voltage. High-frequency interference caused by narrow pulses is effectively eliminated, the circuit stability is improved, meanwhile, it is ensured that a switching device always works in a stable conduction interval, and the service life of hardware is prolonged.

Description

Technical Field

[0001] This invention relates to the field of avionics technology, and in particular to a digital dimming device and method for use in the cockpit of an aircraft or helicopter. Background Technology

[0002] In an aircraft cockpit, the brightness adjustment of various instruments, panels, and indicator lights is crucial for flight safety. Currently, the dimming method for onboard equipment mainly relies on manually adjusting the PWM (Pulse Width Modulation) signal. A problem with this traditional method in practical applications is that when the pilot requires extremely low background light, i.e., a very low PWM duty cycle, the pulse width of the PWM signal becomes extremely narrow. This extremely narrow pulse is prone to generating high-frequency spike interference, which can affect other communication equipment in the cockpit. Simultaneously, the switching transistors may not be able to fully turn on or off within the extremely short conduction time. Prolonged operation in this non-linear state can lead to increased device heating, reduced efficiency, and even damage, shortening the lifespan of the entire system.

[0003] Furthermore, while some existing automatic dimming solutions can adjust brightness according to ambient light, they often lack flexible manual intervention channels. Pilots, under specific mission or personalized visual requirements, cannot make quick, seamless fine adjustments based on automatic dimming, or experience abrupt brightness fluctuations when switching between manual and automatic modes, which can distract them from flight operations.

[0004] Therefore, designing a system that can protect hardware circuits, eliminate low-frequency interference, and provide seamless switching between adaptive and manual operation is an urgent problem to be solved in avionics design. Summary of the Invention

[0005] In view of this, the present invention provides a digital dimming device and method for cockpit equipment, which solves the problem of peak interference by combining voltage regulation and PWM regulation, while providing a smooth automatic and manual switching control experience.

[0006] The technical solution adopted in this invention is: a digital dimming device for cockpit equipment, comprising a main control module and a signal acquisition module connected by electrical signals; characterized in that it further comprises a hybrid dimming drive circuit connected between the main control module and the lighting device, wherein the main control module stores dimming model data;

[0007] The main control module is used to determine the target brightness duty cycle based on the input signal from the signal acquisition module and the dimming model data.

[0008] When the target brightness duty cycle is less than or equal to the preset duty cycle threshold, the main control module outputs a PWM signal with a fixed duty cycle of the preset duty cycle threshold to the hybrid dimming drive circuit, and controls the hybrid dimming drive circuit to reduce the amplitude of the output voltage to change the brightness of the lighting device.

[0009] When the target brightness duty cycle is greater than the preset duty cycle threshold, the main control module controls the hybrid dimming drive circuit to output a voltage with a constant amplitude, and adjusts the duty cycle of the PWM signal output to the hybrid dimming drive circuit to change the brightness of the lighting device.

[0010] Furthermore, the preset duty cycle threshold is 15%.

[0011] Furthermore, the hybrid dimming drive circuit includes an adjustable power supply circuit and a switching transistor connected in series; the main control module includes a digital-to-analog converter output terminal and a pulse width modulation output terminal; the digital-to-analog converter output terminal is connected to the control terminal of the adjustable power supply circuit for adjusting the output voltage of the adjustable power supply circuit; the pulse width modulation output terminal is connected to the control terminal of the switching transistor for controlling the switching transistor's on and off states.

[0012] Furthermore, the signal acquisition module includes a light sensor and a rotary encoder with a push-button switch;

[0013] When the main control module detects the closed signal of the push switch, it switches between adaptive dimming mode and manual dimming mode.

[0014] In the adaptive dimming state, the main control module determines the reference brightness based on the signal from the light sensor, and adjusts the reference brightness based on the signal from the rotary encoder;

[0015] In the manual dimming mode, the main control module directly determines the target brightness duty cycle based on the signal from the rotary encoder.

[0016] Furthermore, when the main control module switches from the adaptive dimming state to the manual dimming state, it reads the current brightness value and sets it as the initial adjustment value for the manual dimming state.

[0017] Furthermore, the main control module is a PSoC chip, which integrates a processor system and programmable logic; the signals acquired by the signal acquisition module are processed by the analog-to-digital converter inside the PSoC chip.

[0018] Furthermore, the main control module is also connected to an RS422 bus interface and a memory; the main control module receives externally input model data through the RS422 bus interface and writes it into the memory; the main control module reads the dimming model data from the memory during power-on initialization.

[0019] A method for digital dimming of cockpit equipment, characterized by comprising the following steps:

[0020] S1, Input signal of the acquisition module;

[0021] S2. Based on the stored dimming model data, map the input signal to the target brightness duty cycle;

[0022] S3. Compare the target brightness duty cycle with a preset duty cycle threshold; if the target brightness duty cycle is less than or equal to the preset duty cycle threshold, then the duty cycle of the output PWM signal is fixed at the preset duty cycle threshold, and the voltage amplitude driving the lighting device is adjusted; if the target brightness duty cycle is greater than the preset duty cycle threshold, then the voltage amplitude driving the lighting device is kept constant, and the duty cycle of the output PWM signal is adjusted.

[0023] The beneficial effects of this invention are: by setting the target brightness below a preset duty cycle threshold, the PWM duty cycle is forcibly locked to a fixed value, ensuring sufficient conduction time for the switching transistor. Furthermore, the brightness is reduced by decreasing the driving voltage amplitude. This effectively eliminates high-frequency interference caused by narrow pulses, improves circuit stability, and ensures that the switching device always operates within a stable conduction range, extending the lifespan of the hardware.

[0024] The moment the system switches from adaptive dimming to manual dimming, the main control module automatically reads the current actual brightness value and sets it as the initial value for manual adjustment. This design ensures a smooth transition during mode switching, reducing the distraction to the pilot's attention. Furthermore, the adaptive dimming mode of this invention not only automatically adjusts brightness according to ambient light but also retains the fine-tuning function of the knob. This allows the pilot to manually intervene at a reference brightness level, reducing the burden of frequent operations while meeting personalized visual needs in specific scenarios. Attached Figure Description

[0025] Figure 1 This is a hardware principle block diagram of the present invention;

[0026] Figure 2 This is the control logic flowchart for adaptive dimming mode;

[0027] Figure 3 This is the control logic flowchart for manual dimming mode;

[0028] Figure 4 This is a circuit connection diagram for the dimming model injection function. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1As shown, this embodiment provides a digital dimming device for cockpit equipment, including a main control module, a signal acquisition module, a hybrid dimming drive circuit, a lighting device, and a communication storage unit. In this embodiment, the main control module uses a PSoC chip. The PSoC chip integrates a microprocessor core (MCU), a programmable digital logic FPGA, an analog-to-digital converter (ADC), and a digital-to-analog converter (DAC). The main control module, as the core processing unit, is electrically connected to the signal acquisition module, the hybrid dimming drive circuit, the RS422 bus interface, and the memory. It should be noted that the lighting device is an LED panel or instrument backlight, etc.

[0031] The hybrid dimming drive circuit is connected between the main control module and the lighting device in series. The hybrid dimming drive circuit includes an adjustable power supply circuit and a switching transistor. The control terminal of the adjustable power supply circuit is connected to the analog-to-digital converter output of the main control module. The main control module adjusts the output voltage amplitude of the adjustable power supply circuit by outputting an analog voltage signal or a PWM signal. The switching transistor is connected in series with the adjustable power supply circuit. The switching transistor can be a MOSFET, and its control terminal is connected to the pulse width modulation output of the main control module. The main control module controls the rapid on / off switching of the switching transistor by outputting a high-frequency PWM signal. The power supply voltage of the lighting device is determined by the adjustable power supply circuit, while the on / off time of the lighting device is determined by the switching transistor. Together, they achieve hybrid adjustment of the lighting device's brightness.

[0032] The signal acquisition module includes a light sensor and a rotary encoder. The light sensor collects ambient light intensity signals within the cockpit and transmits this analog signal to the analog-to-digital converter in the main control module. In this embodiment, a rotary encoder with a push-button switch is selected. Its output includes two signals: one is a pulse signal reflecting the rotation direction and angle of the knob; the other is a switch signal reflecting whether the knob is pressed.

[0033] The communication storage unit includes a memory and an RS422 bus interface. In this embodiment, a Flash memory is used, connected to the main control module, to store dimming model data and configuration parameters. The RS422 bus interface is used to connect to external ground maintenance equipment to achieve bidirectional data transmission.

[0034] like Figure 4As shown, since different aircraft models or mission scenarios have different requirements for dimming curves, the device designed in this invention supports external injection of dimming models. The main control module receives dimming model data packets sent by an external host computer via an RS422 bus interface. The main control module writes the received data into the Flash memory. During the initialization of each device startup, the main control module reads the latest dimming model data from the Flash memory and establishes a mapping relationship between signal and brightness accordingly. Through the RS422 interface and Flash memory settings, maintenance personnel can update the dimming curve simply by externally storing data without disassembling the device or modifying the code. This allows the same hardware device to flexibly adapt to different aircraft models, mission environments, or the visual preferences of different pilots, greatly reducing the maintenance cost and upgrade complexity of the equipment.

[0035] The main control module internally stores dimming model data, which defines the mapping relationship between the input signal (ambient light or the knob value of the photoelectric encoder) and the output target brightness. In this embodiment, the PSoC chip, acting as the main control module, executes hybrid dimming logic based on the input signal from the signal acquisition module and the dimming model data, such as... Figure 2 As shown, the specific steps are as follows:

[0036] First, the main control module collects the input signals from the signal acquisition module in real time, and calculates the target brightness duty cycle that the lighting device should achieve at the current moment based on the dimming model data.

[0037] Next, the main control module compares the calculated target brightness duty cycle with a preset duty cycle threshold. In this embodiment, the preset duty cycle threshold is set to 15%.

[0038] Third, when the target brightness duty cycle is ≤15%, in order to avoid the PWM pulse width being too narrow, the main control module locks the duty cycle of the PWM signal, making its output fixed at 15%. At this time, further reduction of the brightness of the lighting device is no longer adjusted by shortening the PWM pulse time, but by the main control module adjusting the output terminal of the digital-to-analog converter to control the adjustable power supply circuit to reduce the amplitude of the output voltage.

[0039] When the target brightness duty cycle is greater than 15%, the main control module controls the adjustable power supply circuit to output a constant rated voltage. At this time, the change in the brightness of the lighting device is achieved entirely by adjusting the duty cycle of the PWM signal output to the switching transistor.

[0040] Through the above-described steps, this invention solves the problems of electromagnetic interference and device instability in PWM dimming under low duty cycle.

[0041] This embodiment can also switch between adaptive dimming and manual dimming modes to meet the personalized visual needs of operators, as detailed below:

[0042] like Figure 3 As shown, when the device proposed in this embodiment defaults to adaptive dimming mode upon startup, or switches to this mode, the main control module executes the following process: It reads the ambient light signal from the light sensor and determines the reference brightness based on the dimming model data. Simultaneously, it monitors the rotation signal of the rotary encoder. If rotation is detected, the rotation amount is superimposed on the reference brightness, and the final target brightness duty cycle is calculated. This achieves fine-tuning functionality based on automatic dimming.

[0043] To achieve seamless switching between adaptive and manual modes, the main control module monitors the rotary encoder's push-button switch signal in real time. Upon detecting a push-button action, the mode is switched, and at the instant of the switch, the main control module reads the current brightness value and sets it as the initial adjustment value for manual dimming. This ensures that the brightness of the lighting device remains constant during the switch from adaptive to manual mode, preventing sudden changes in brightness from interfering with the pilot's vision.

[0044] After entering manual dimming mode, the main control module ignores the signal from the light sensor. The target brightness duty cycle is directly adjusted based on the rotation direction and angle of the rotary encoder, increasing or decreasing from the initial value mentioned above.

Claims

1. A digital dimming device for cockpit equipment, comprising a main control module and a signal acquisition module connected by electrical signals; characterized in that, It also includes a hybrid dimming drive circuit connected between the main control module and the lighting device, wherein the main control module stores dimming model data; The main control module is used to determine the target brightness duty cycle based on the input signal from the signal acquisition module and the dimming model data. When the target brightness duty cycle is less than or equal to the preset duty cycle threshold, the main control module outputs a PWM signal with a fixed duty cycle of the preset duty cycle threshold to the hybrid dimming drive circuit, and controls the hybrid dimming drive circuit to reduce the amplitude of the output voltage to change the brightness of the lighting device. When the target brightness duty cycle is greater than the preset duty cycle threshold, the main control module controls the hybrid dimming drive circuit to output a voltage with a constant amplitude, and adjusts the duty cycle of the PWM signal output to the hybrid dimming drive circuit to change the brightness of the lighting device.

2. The cockpit equipment digital dimming device according to claim 1, characterized in that, The preset duty cycle threshold is 15%.

3. The cockpit equipment digital dimming device according to claim 1, characterized in that, The hybrid dimming drive circuit includes an adjustable power supply circuit and a switching transistor connected in series; the main control module includes a digital-to-analog converter output terminal and a pulse width modulation output terminal; the digital-to-analog converter output terminal is connected to the control terminal of the adjustable power supply circuit for adjusting the output voltage of the adjustable power supply circuit; the pulse width modulation output terminal is connected to the control terminal of the switching transistor for controlling the switching transistor's on and off states.

4. The cockpit equipment digital dimming device according to claim 1, characterized in that, The signal acquisition module includes a light sensor and a rotary encoder with a push-button switch; When the main control module detects the closed signal of the push switch, it switches between adaptive dimming mode and manual dimming mode. In the adaptive dimming state, the main control module determines the reference brightness based on the signal from the light sensor, and adjusts the reference brightness based on the signal from the rotary encoder; In the manual dimming mode, the main control module directly determines the target brightness duty cycle based on the signal from the rotary encoder.

5. The cockpit equipment digital dimming device according to claim 4, characterized in that, When the main control module switches from the adaptive dimming state to the manual dimming state, it reads the current brightness value and sets it as the initial adjustment value for the manual dimming state.

6. The cockpit equipment digital dimming device according to claim 1, characterized in that, The main control module is a PSoC chip, which integrates a processor system and programmable logic; the signals acquired by the signal acquisition module are processed by the analog-to-digital converter inside the PSoC chip.

7. The cockpit equipment digital dimming device according to claim 1, characterized in that, The main control module is also connected to an RS422 bus interface and a memory; the main control module receives externally input model data through the RS422 bus interface and writes it into the memory; the main control module reads the dimming model data from the memory during power-on initialization.

8. A digital dimming method for cockpit equipment, applied to the apparatus as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1, Input signal of the acquisition module; S2. Based on the stored dimming model data, map the input signal to the target brightness duty cycle; S3. Compare the target brightness duty cycle with a preset duty cycle threshold; If the target brightness duty cycle is less than or equal to the preset duty cycle threshold, the duty cycle of the output PWM signal is fixed to the preset duty cycle threshold, and the voltage amplitude driving the lighting device is adjusted. If the target brightness duty cycle is greater than the preset duty cycle threshold, the voltage amplitude driving the lighting device is kept constant, and the duty cycle of the output PWM signal is adjusted.

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