LED power supply safety control system and method with over-temperature protection function

Abstract

The invention discloses an LED power supply safety control system and method with an over-temperature protection function, particularly relates to the technical field of LED driving power supply thermal management, and aims to solve the problem of visual stroboflash induced when a traditional over-temperature protection mechanism is implemented. The temperature of a key part of a power supply is monitored in real time, and luminous flux response delay characteristics and human eye vision sensitive frequency parameters of a light source are obtained during overtemperature; calculating a light fluctuation frequency component caused by the power derating operation based on the delay parameter; analyzing dynamic visual adaptation characteristics in combination with environment illumination changes; amending to obtain a perception sensitivity equivalent frequency; when the frequency is lower than a human eye sensitive threshold value, optimizing the derating rate through closed-loop iteration to enable the derating rate to reach the standard; and finally executing power derating according to the optimization rate. Decoupling of a thermal protection process and human eye visual perception is realized, and a light source stroboflash phenomenon is eliminated while thermal safety of a power supply is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of LED drive power thermal management. More specifically, the present invention relates to an LED power supply safety control system and method with an over-temperature protection function. Background Art

[0002] LED lighting devices are widely used due to their high efficiency and energy-saving characteristics. As the core component of an LED drive power supply, when operating in a high-temperature environment, the reliability of internal electronic components faces severe challenges. To prevent permanent damage to components or even safety accidents caused by excessive temperature, modern LED drive power supplies generally integrate an over-temperature protection (OTP) function. A common protection strategy is to actively reduce the output power (i.e., implement a "derating" operation) when the temperature at a critical part of the power supply is detected to exceed a preset safety threshold, and suppress the temperature rise by reducing its own power consumption, trying to stabilize the temperature within a safe range, so as to achieve hardware protection while maintaining uninterrupted lighting. This OTP method based on power derating has become an important and widely adopted safety control means in the industry.

[0003] However, the existing over-temperature protection schemes based on the active derating mode face the following problems during implementation: If the time characteristics of the power reduction rate adjustment (i.e., the speed and law of the derating process) do not match the optoelectronic response characteristics of the LED light source it drives (such as the delay and inertia of the light flux change), it will induce specific fluctuation modes in the light source output. If this fluctuation falls into the low-frequency range that is sensitive to the perception of the human visual system, even if the power supply itself has effectively avoided the overheating risk and continuously provides lighting, it will cause uncomfortable or disturbing flicker phenomena in the application scenario (especially in occasions with strict requirements for lighting quality). Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an LED power supply safety control system and method with an over-temperature protection function to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solutions: An LED power supply safety control method with an over-temperature protection function, comprising the following steps: S1. Real-time monitor the temperature value of the critical part of the LED power supply. When the temperature value exceeds the set protection threshold, obtain the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitive frequency; S2. Calculate the light fluctuation frequency component corresponding to the current initial derating rate according to the light flux response delay time constant; S3. Detect the changing trend of the ambient light source intensity, and analyze the dynamic visual adaptation characteristics based on the changing trend of the ambient light source intensity; S4. Modify the perception sensitivity of the light fluctuation frequency component according to the dynamic visual adaptation characteristics to generate an equivalent frequency of the perception sensitivity; S5. When the equivalent frequency of the perception sensitivity is lower than the lower limit value of the human eye visual sensitivity frequency, increase the initial derating rate until the newly generated equivalent frequency of the perception sensitivity is not lower than the lower limit value of the human eye visual sensitivity frequency, and obtain the optimized derating rate; S6. Perform the output power derating operation according to the optimized derating rate.

[0006] In a preferred embodiment, the temperature value of the key part of the LED power supply is monitored in real time. When the temperature value exceeds the set protection threshold, the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency are obtained, including: Synchronously sample the junction temperature of the power switch tube and the surface temperature of the magnetic component of the LED power supply; When any sampled temperature value exceeds the set protection threshold three times in a row, it is determined that the over-temperature protection trigger condition is met; While triggering the over-temperature protection condition, obtain the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency.

[0007] In a preferred embodiment, obtaining the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency specifically includes: Obtain the LED light source package model code of the current drive circuit, query the light source characteristic mapping table pre-stored in the non-volatile memory according to the LED light source package model code, and extract the corresponding light flux response delay time constant from the light source characteristic mapping table; Read the current lighting scene classification identifier through the scene recognition interface, and retrieve the lower limit value of the human eye visual sensitivity frequency associated with the corresponding scene from the visual perception parameter database.

[0008] In a preferred embodiment, calculating the light fluctuation frequency component corresponding to the current initial derating rate according to the light flux response delay time constant includes: Read the initial derating rate stored in the microcontroller of the current drive circuit; Obtain the current valid value of the light flux response delay time constant; Establish a conversion model based on the inverse relationship between the light flux response delay time constant and the light fluctuation frequency component; Input the initial derating rate into the conversion model for calculation; Output the numerical value of the light fluctuation frequency component corresponding to the current initial derating rate.

[0009] In a preferred embodiment, the change trend of the ambient light source intensity is detected, and the dynamic visual adaptation characteristics are analyzed based on the change trend of the ambient light source intensity, including: Detecting the sequence of illuminance measurement values of the current ambient illumination light source at three consecutive sampling time points; Identifying the position order of the maximum and minimum measurement values in the illuminance sequence; Determining the change direction of the illuminance as an increasing trend or a decreasing trend according to the position order; When the change direction is an increasing trend, selecting the reference adaptation time dominated by photopic vision from the preset physiological parameter library; When the change direction is a decreasing trend, selecting the reference adaptation time dominated by scotopic vision from the preset physiological parameter library; Based on the absolute value of the illuminance change rate and the change direction combination, correcting the reference adaptation time: shortening the photopic adaptation time constant according to the change rate ratio under the increasing trend, and lengthening the scotopic adaptation time constant according to the change rate ratio under the decreasing trend; Outputting a two-channel dynamic visual adaptation characteristic set carrying directional characteristics.

[0010] In a preferred embodiment, the perception sensitivity of the light fluctuation frequency component is corrected according to the dynamic visual adaptation characteristics to generate a perception sensitivity equivalent frequency, including: Extracting the photopic adaptation time constant and the scotopic adaptation time constant from the dynamic visual adaptation characteristic parameter set; Inputting the photopic adaptation time constant into the physiological response conversion function to calculate the photopic perception gain factor; Inputting the scotopic adaptation time constant into the time integration operator to calculate the scotopic cumulative effect factor; Performing two-way frequency domain modulation on the light fluctuation frequency component; Combining the modulation results to generate a phase-continuous perception sensitivity equivalent frequency output value.

[0011] In a preferred embodiment, the two-way frequency domain modulation includes: the photopic perception gain factor acts to enhance the high-frequency response of the frequency component; the scotopic cumulative effect factor acts to suppress the low-frequency fluctuation of the frequency component.

[0012] In a preferred embodiment, when the perception sensitivity equivalent frequency is lower than the lower limit value of the human eye visual sensitive frequency, increasing the initial derating rate until the newly generated perception sensitivity equivalent frequency is not lower than the lower limit value of the human eye visual sensitive frequency to obtain an optimized derating rate, including: Establishing a comparison relationship between the current perception sensitivity equivalent frequency and the lower limit value of the human eye visual sensitive frequency; When the comparison result shows lower, setting the initial derating rate change step value; Increasing the current derating rate value according to the initial derating rate change step value; Regenerate the optical fluctuation frequency component based on the increased derating rate value; Perform a perceptual sensitivity correction operation on the regenerated optical fluctuation frequency component to generate a new perceptual sensitivity equivalent frequency; Compare the newly generated perceptual sensitivity equivalent frequency with the lower limit value of the human eye visual sensitivity frequency again; Repeat the operation loop of increasing the derating rate and regenerating the comparison; When the newly generated perceptual sensitivity equivalent frequency reaches not less than the lower limit value of the human eye visual sensitivity frequency, terminate the operation loop; Record the effective derating rate value at this time as the optimized derating rate output.

[0013] In a preferred embodiment, perform the output power derating operation according to the optimized derating rate, including: Load the value stored in the dedicated storage area for the optimized derating rate and convert it into the waveform parameters of the power control signal; Configure the driving timing sequence of the power switch tube and generate a pulse width modulation waveform according to the driving timing sequence; Transmit the pulse width modulation waveform to the gate of the power switch tube through the isolation driving circuit; Real-time monitor the change gradient of the output power and adjust the duty cycle change rate of the pulse width modulation waveform; When the deviation between the output power change gradient and the optimized derating rate exceeds the allowable range, start the duty cycle fine-tuning compensation mechanism; After confirming that the output power is stable at the target derating value, lock the current driving parameters to maintain the power output.

[0014] On the other hand, the present invention provides an LED power supply safety control system with an over-temperature protection function, including the following modules: A parameter acquisition module, used to real-time monitor the temperature value of the key parts of the LED power supply. When the temperature value exceeds the set protection threshold, obtain the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency; A component calculation module, used to calculate the optical fluctuation frequency component corresponding to the current initial derating rate according to the optical flux response delay time constant; An adaptation analysis module, used to detect the change trend of the ambient light source intensity and analyze the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity; A perception correction module, used to perform a perception sensitivity correction on the optical fluctuation frequency component according to the dynamic visual adaptation characteristics to generate a perception sensitivity equivalent frequency; A rate optimization module, used to increase the initial derating rate until the newly generated perception sensitivity equivalent frequency is not less than the lower limit value of the human eye visual sensitivity frequency when the perception sensitivity equivalent frequency is lower than the lower limit value of the human eye visual sensitivity frequency, so as to obtain the optimized derating rate; The derating execution module is used to perform the output power derating operation according to the optimized derating rate.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. By establishing a deep coupling mechanism between the optoelectronic response characteristics of the light source and the human eye visual perception model, the stroboscopic problem in traditional LED power supply over-temperature protection is solved. By dynamically mapping the light flux response delay parameter into frequency components and combining the visual adaptation characteristics driven by ambient light for perception correction, an equivalent frequency evaluation model sensitive to the human eye vision is constructed, realizing the precise matching between the power reduction process and the stroboscopic characteristics of the light source, and ensuring that the light fluctuation generated by the derating operation is always higher than the human eye sensitive threshold. On the premise of maintaining the thermal safety protection ability, the interference of the light source output fluctuation on visual work is significantly reduced, especially suitable for places sensitive to visual quality such as surgical lighting and precision laboratories, improving the comfort and usability of lighting.

[0016] 2. Adopt a closed-loop optimization architecture to dynamically adjust the derating trajectory: By comparing the equivalent frequency with the human eye sensitive threshold in real time, adaptively optimize the power adjustment rate, and achieve the best balance between the power supply thermal time constant and the visual perception boundary, which can not only quickly suppress the temperature rise, but also avoid the protection delay caused by excessive derating. It not only ensures the thermal safety margin of electronic components, but also ensures the stability of the light environment, realizing the collaborative optimization of hardware reliability and visual comfort. Description of the Drawings

[0017] Figure 1 is a flowchart of the LED power supply safety control method with over-temperature protection function of the present invention; Figure 2 is a schematic structural diagram of the LED power supply safety control system with over-temperature protection function of the present invention. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Embodiment 1: Figure 1 The LED power supply safety control method with over-temperature protection function of the present invention is given, which includes the following steps: S1. Real-time monitor the temperature value of the key parts of the LED power supply. When the temperature value exceeds the set protection threshold, obtain the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitive frequency; S2. Calculate the light fluctuation frequency component corresponding to the current initial derating rate according to the light flux response delay time constant; S3. Detect the change trend of the ambient light source intensity, and analyze the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity; S4. Perform perception sensitivity correction on the light fluctuation frequency component according to the dynamic visual adaptation characteristics to generate a perception sensitivity equivalent frequency; S5. When the perception sensitivity equivalent frequency is lower than the lower limit value of the human eye visual sensitive frequency, increase the initial derating rate until the newly generated perception sensitivity equivalent frequency is not lower than the lower limit value of the human eye visual sensitive frequency to obtain an optimized derating rate; S6. Perform the output power derating operation according to the optimized derating rate.

[0020] S1. Monitor the temperature value of the key parts of the LED power supply in real time. When the temperature value exceeds the set protection threshold, obtain the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitive frequency. The specific implementation is as follows: The real-time monitoring of the temperature value of the key parts of the LED power supply is specifically realized in the following way: The thermistor diode integrated inside the metal oxide semiconductor field effect transistor chip is used to monitor the semiconductor junction temperature. The inverse relationship between the forward voltage drop of the diode and the temperature is converted into an analog voltage signal of 0 to 5 volts through an application-specific integrated circuit. This signal is connected to the 12-bit analog-to-digital converter channel built into the microcontroller and sampled at a rate of once every 10 milliseconds. The sampled value is converted into a Celsius temperature value through a linear interpolation formula, and the temperature conversion coefficient is 0.5 degrees Celsius per millivolt. The surface temperature of the transformer core is monitored by a negative temperature coefficient thermistor device encapsulated with epoxy resin. Its nominal resistance value at 25 degrees Celsius is 10 kΩ, and the thermistor constant is -3950 / °C. The thermistor is connected as one arm of a Wheatstone bridge circuit. The differential voltage output by the bridge is amplified 20 times by an instrumentation amplifier and then sent to the analog-to-digital converter. The sampling timing of the two temperature acquisition channels is controlled by the general timer module of the microcontroller. The timer is configured in the up-counter mode. When the count value reaches 1000, a start signal for analog-to-digital conversion is triggered to ensure that the sampling interval error is less than 1%.

[0021] When the sampled value of the power switch tube junction temperature or the surface temperature of the magnetic component exceeds the preset threshold of 135 degrees Celsius continuously for 3 times, it is determined that the over-temperature protection trigger condition is met. This determination is executed by two independent 8-bit shift registers: the sampled value of the power switch tube temperature is stored in the first shift register, and the temperature of the magnetic component is stored in the second shift register. After each sampling, the value is compared with the threshold. When it is higher than the threshold, a digital 1 is shifted into the lowest bit of the corresponding shift register, otherwise a digital 0 is shifted in. When the lowest 3 bits of any register are all digital 1s, the corresponding flag bit of the over-temperature protection status register is immediately set. This flag bit is implemented by a set-priority flip-flop, and the response delay of the status change is less than 100 nanoseconds.

[0022] While the over-temperature protection status flag is set, the parameter acquisition operation is started. The 6-character package model code stored in the 1024-bit electrically erasable programmable read-only memory on the light-emitting diode light source substrate is read through the serial peripheral interface bus. The encoding format conforms to the alphanumeric specification defined by the International Electrotechnical Commission Standard 62203. This code is used as a query key value to access the light source characteristic mapping table stored in Block 0 of the serial flash memory. The mapping table data structure is a fixed-length record type, and each record contains a 16-byte encoded string and a 4-byte floating-point time constant value. The method for obtaining the luminous flux response delay time constant is as follows: During the production test stage of the light-emitting diode, a step excitation that jumps from 10% to 90% of the nominal current is applied using a programmable current source. At the same time, the output voltage waveform of the high-speed photodiode is collected at a sampling rate of 1,000,000 times per second. The time interval during which the output voltage rises from 10% of the steady-state value to 90% of the steady-state value is calculated, and this time value is multiplied by a thermoelectric conversion coefficient of 0.85 and used as the stored value in the mapping table. This coefficient is obtained by calibrating the difference in response times at ambient temperatures of 25°C and 85°C.

[0023] The scene classification identifier is obtained through a dual-path mechanism: The physical path detects the state combination of a 4-way DIP switch. The on / off state of each switch corresponds to a 1-bit binary value. When the switch is grounded, the reading is 0, and when it is connected to a 3.3V power supply, the reading is 1. The 4-bit combination forms an integer identification code from 0 to 15. The electrical path analyzes the standard identifier field of the controller area network bus data frame and takes the data from bits 18 to 21 of the extended identifier to form the scene identification code. The identification code is used as an index key to query the visual perception parameter database stored in the electrically erasable programmable read-only memory. The database organizes data records using a balanced binary tree structure. Each record contains a 4-byte scene identification code and a 4-byte single-precision floating-point frequency parameter. The method for setting the lower limit value of the human eye's visual sensitivity frequency is as follows: First, refer to the standard luminousness function curve published by the International Commission on Illumination to obtain the reference value of the critical flicker frequency under the light adaptation state in the curve. Then, a dynamic margin is added to the reference value. The dynamic margin is increased by 2.0 Hz for the operating room scene, 1.0 Hz for the road lighting scene, and 3.0 Hz for the cinema scene. The principle of setting the dynamic margin is based on the visual task accuracy requirements of different scenes. The operating room scene requires high visual recognition accuracy, so a larger margin is set.

[0024] The exception handling mechanism includes the following hierarchical design: When an unregistered encapsulated model code is detected, the preset global default value of 1.5 milliseconds is automatically called as the optical flux response delay time constant, which is determined by the median of the parameters of 50 common light-emitting diode models; when the scene identification code verification is incorrect, the default frequency value corresponding to the road lighting scene of 8.0 Hz is forcibly adopted; when the read operation of the non-volatile memory returns a verification error, it is automatically retried 3 times and then switched to the same logical address in the backup storage area to read data; the hardware watchdog timer is set to a timeout period of 500 milliseconds, and a system reset signal is triggered when the timer overflows. The memory access verification uses the cyclic redundancy check algorithm, with the generating polynomial being hexadecimal 11021 (decimal 69665) and the check bit width being 16 bits.

[0025] Hardware implementation verification method for key technical parameters: The temperature monitoring accuracy is calibrated using a first-class standard platinum resistance thermometer in a constant temperature bath, and the maximum error within the working temperature range of -40°C to 125°C is ±2.5°C; the optical flux delay time is measured by generating a drive current with a 2.5-microsecond rising edge using a programmable current source, and is verified using a 200-MHz bandwidth optical probe in cooperation with a high-speed oscilloscope, with the deviation between the measured data and the stored value being less than 3%; the scene parameter retrieval delay is measured using a logic analyzer to measure the timestamps of the controller area network bus data frame transmission and reception, with a maximum response delay of 110 microseconds; the memory reliability test is to continuously read and write 10,000 times at an ambient temperature of 85°C, and the bit error rate is lower than 1×10 -9 . The system reset function is verified by artificially injecting a register lock-up fault, and the system automatically resumes operation within 499 milliseconds after the fault injection.

[0026] S2. Calculate the optical fluctuation frequency component corresponding to the current initial derating rate according to the optical flux response delay time constant. The specific implementation is as follows: The acquisition mechanism of the initial derating rate is executed through the direct memory access channel of the microcontroller. This parameter is stored in a dedicated register at the hexadecimal address 0x7E08 in the memory mapping area. The register uses a 32-bit fixed-point number format: the upper 16 bits store the integer part, and the lower 16 bits store the fractional part. When the system detects that the over-temperature protection trigger condition is established, the firmware starts a direct memory access transfer, configured in single transfer mode and setting the data width to four bytes. The original value read needs to be multiplied by the coefficient 0.001 to convert it into the actual derating rate value. The setting of this coefficient is determined according to the power supply rated power range: for a 100-watt level power supply, 0.001 is used, and for a 200-watt level, 0.0005 is used. The conversion operation is completed in the arithmetic logic unit and takes no more than 500 nanoseconds.

[0027] The extraction process of the optical flux response delay time constant is based on the package model code obtained from the previous steps. The system sends a query instruction to the serial flash memory through a four-wire serial peripheral interface, and the clock frequency is configured to 15 megahertz. The instruction frame contains a six-byte encoded string and a two-byte check code, and the check algorithm uses cyclic redundancy check with a polynomial of 0x11021. The flash memory performs a sequential search operation in the light source characteristic mapping table starting from the address 0x1000, and each record occupies 20 bytes of storage space. After successful matching, a four-byte single-precision floating-point number is extracted from the 12-byte offset address of the record as the valid constant. This value needs to pass a numerical range check before being loaded into the processor to ensure it is in the range of 0.1 to 10.0 milliseconds.

[0028] The construction method of the conversion model is based on the principle of the dynamic response of the light source. The determination of the reference conversion coefficient (k) is achieved through laboratory measurements: ten typical LED package models are selected, a programmable current source is used to apply a step change in the rated current from 10% to 90%, and the optical flux rise curve is recorded at a sampling interval of 500 nanoseconds. The time taken to rise from 10% to 90% of the steady-state value is calculated as the delay constant (τ), and at the same time, the fundamental frequency component (f) of the output light fluctuation is captured using a spectrum analyzer. The τ·f product values of multiple groups of data are statistically analyzed, and the median of the fifth to fifteenth data after sorting all the product values is taken, and then this median is multiplied by a constant factor of 3.1416 as the final reference conversion coefficient. When the system is initialized, the reference conversion coefficient is written into the read-only configuration area, and the address range is from 0x2000 to 0x2003.

[0029] The calculation operations are executed in a strict sequence in the floating-point processing unit: in the first step, the optical flux response delay time constant is loaded into the floating-point register FP0; in the second step, the reference conversion coefficient is loaded into the register FP1; in the third step, the division operation FP1 / FP0 is performed, and the result is stored in the intermediate register TMP; in the fourth step, the initial derating rate is loaded into the register FP2; in the fifth step, the division operation TMP / FP2 is performed, and the result is stored in the target register DST. Each arithmetic operation uses the IEEE 754 single-precision floating-point standard, and the rounding mode is set to round to the nearest even number. The hardware overflow monitoring is enabled during the calculation process, and a floating-point exception interrupt is triggered when it is detected that the exponent part exceeds 126.

[0030] Perform triple validity verification before outputting the calculation result: The first level checks whether the value is within the range of 0.1 to 1000.0 Hz; the second level confirms that the value sign is positive; the third level verifies that the value precision reaches 23 significant figures in binary. The verified data is written to the memory buffer area from 0x3000 to 0x3FFF, and the data format is stored in four-byte alignment. At the same time, update the third bit flag at address 0x5002 in the status register. If the verification fails, the system enables an alternative solution: call the default frequency value of 5.0 Hz stored at address 0x4004 as the output and record the event code 0xE1 in the error log.

[0031] The exception handling system includes a hierarchical fault tolerance mechanism. Coping strategies when parameters are invalid: When the optical flux response delay time constant is less than 0.1 ms, automatically switch to 1.2 ms; when it is greater than 10.0 ms, switch to 8.0 ms; when the initial derating rate is 0.0 per second, use 0.5 per second instead. The fault counter records the number of operation exceptions at address 0x6000, and activates the safe mode after reaching the three-time threshold. In the safe mode, the system bypasses the calculation process and directly outputs a fixed value of 10.0 Hz. All exception events are recorded in real time to the non-volatile memory log area, and each log occupies 16 bytes: 4-byte timestamp (in milliseconds), 4-byte error code, and 8-byte additional information.

[0032] The hardware resource configuration requirements are clear: The calculation process needs to run on a microcontroller equipped with a hardware floating-point unit, and the minimum main frequency requirement is 30 MHz. The memory allocation requirements are: 8 bytes for the input parameter area, 8 bytes for the intermediate calculation area, and 4 bytes for the output area. The real-time performance index is monitored by a hardware timer, and the total calculation time limit is 200 microseconds, including: 50 microseconds for the parameter loading stage, 100 microseconds for the division operation stage, and 50 microseconds for the verification output stage. Temperature adaptability measures include: Relax the calculation time limit to 240 microseconds at an ambient temperature of -40°C, and reduce the memory access frequency by 20% at a high temperature of 85°C.

[0033] The verification test plan establishes a complete benchmark framework: The test platform includes a programmable parameter injection module, which supports combined test vectors of the input optical flux response delay time constant (0.5 - 5.0 ms) and the initial derating rate (2 - 10 per second). Use a 500MHz bandwidth oscilloscope to monitor the key nodes of the calculation process: Monitor the input parameter loading status of the address bus signal; analyze the intermediate results of the data bus; detect the error status of the floating-point exception pin. The accuracy verification method is to compare the theoretical calculation value with the system output value, and the allowable deviation is set to ±5%. The long-term reliability test is performed in a temperature cycling chamber: 2000 temperature cycles from -40°C to 85°C, with a temperature change rate of 5°C / minute each time, and the test lasts for 500 hours in total. The test result requires an error rate of less than 0.01%.

[0034] All units are represented in international standards: time in ms (millisecond), frequency in Hz (Hertz), and rate in % / s (percent per second). Numerical representation rules: for values with an integer part exceeding three digits, commas are added every three digits (e.g., 1,000), and floating-point numbers are retained to three significant figures. Physical constants used in the calculation process are accurate to four decimal places, where the value of pi is taken as 3.1416 and the base of the natural logarithm is taken as 2.7183. The time performance indicators for core operations are: the longest parameter loading time is 42 microseconds, the average division operation time is 92 microseconds, and the minimum result output time is 38 microseconds. System recovery time indicators: soft error recovery is less than 10 microseconds, and hard reset recovery is less than 1 millisecond.

[0035] Dynamic update mechanism for the reference conversion coefficient: The coefficient calibration process can be re-executed through the system maintenance interface. After the new coefficient is calculated, it is written to the address segment of the backup storage area at 0x8000. Before writing, two independent calculation validations are required. After verification is consistent, a storage area switching operation is performed: update the memory address mapping table, and redirect the addresses from 0x2000 to 0x2003 to the new data area. The update process needs to be completed before the next over-temperature protection trigger. The system records the update log and saves the previous version of the coefficient as a rollback copy. Operators can set an automatic update cycle from three months to one year to ensure that the coefficient matches the aging characteristics of the light source.

[0036] S3. Detect the change trend of the ambient light source intensity, and analyze the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity. The specific implementation is as follows: The illuminance measurement of the ambient lighting source is performed by three groups of photoelectric sensing units arranged on the device monitoring surface. Each group of units includes a photodiode and a current-voltage conversion circuit. The three units are arranged in a ring at a 120-degree angle and are synchronously triggered for sampling every 10 milliseconds. The sampling timing is controlled by the rising edge of channel 1 of the microcontroller timer 3. The analog voltage output by each sensing unit is quantized to an integer value in the range of 0 - 4095 by a 12-bit analog-to-digital converter, and this value is linearly mapped to the actual illuminance value in the range of 0 - 100,000 lux. The data at three consecutive sampling time points form a time series and are stored in the buffer. The buffer management adopts a first-in, first-out strategy: new data overwrites the oldest data, always keeping the most recent three sampling data sets.

[0037] The process for identifying the extreme value positions in the illuminance sequence is as follows: Load the measured values at three time points in the buffer into the comparator array. The first comparator compares the numerical values of time stamps t0 and t1 and outputs the index mark of the larger value; the second comparator compares t1 and t2; the third comparator finally determines the position indexes of the global maximum and minimum values. The position index is defined as the time point serial number (0 represents t0, 1 represents t1, 2 represents t2), and the index value is stored in bits [7:6] of the processor's status register. This operation takes no more than 200 nanoseconds to ensure real-time performance.

[0038] The change direction determination is based on the positional logical relationship between the maximum value and the minimum value: when the maximum value index is equal to 2 and the minimum value index is equal to 0, an increasing trend is marked; when the maximum value index is equal to 0 and the minimum value index is equal to 2, a decreasing trend is marked. The determination result is stored in status register bit [5], and the change of the status of this bit triggers the subsequent parameter selection operation in real time. In scenes with drastic light fluctuations (such as lightning), the system enables a noise suppression mechanism: when the change in the difference between adjacent time points exceeds 50%, the judgment is postponed and re-analyzed in the next sampling period.

[0039] When an increasing trend is detected, access the photopic vision parameter area pre-set in a specific address range of the serial flash memory chip. This area stores the physiologically verified photopic vision reference adaptation time constant, the source of which is based on the cone cell response data in the International Commission on Illumination (CIE) Publication 200:2011 standard. The reference constant value is initially set to 140 milliseconds (standard value at 25°C), and the storage format is single-precision floating-point. The selection operation is completed by sending a read command to the physical address 0x5000 of the chip through the Serial Peripheral Interface (SPI) bus, and the data transfer rate is 20 Mbps.

[0040] When a decreasing trend is detected, access the scotopic vision parameter area starting from the address 0x6000 of the same storage chip. The scotopic vision reference constant is taken from the study of the rod cell recovery characteristics in the CIE standard, and the reference value is set to 1800 milliseconds. The read command format includes an 8-bit operation code and a 24-bit address field, and the 32-bit data returned by the chip is directly loaded into the floating-point register of the processor. In a high-temperature environment (>70°C), the system automatically activates the temperature compensation function: the read value is multiplied by a temperature attenuation factor, and the attenuation coefficient decreases by 0.1% for every 1°C increase.

[0041] The steps for calculating the illuminance change rate and correcting the reference time are as follows: First, calculate the absolute value of the maximum illuminance change within three time points (i.e., the difference between the maximum value and the minimum value). Divide the absolute value of the change by the sampling time window of 20 milliseconds (the total span of three sampling points with an interval of 10 milliseconds) to obtain the absolute value of the change rate (unit: kLux / s). The correction rule is implemented as follows: for an increasing trend, the calculation formula for the light adaptation time constant is "reference value minus (change rate multiplied by the proportionality factor)", and the proportionality factor is fixed at 0.04 ms·s / kLux; for a decreasing trend, the calculation formula for the dark adaptation time constant is "reference value plus (change rate multiplied by the proportionality factor)", and the proportionality factor is 0.06 ms·s / kLux. The theoretical basis for the proportionality factor is the Alpern visual pigment bleaching and recovery curve model, and it is calibrated by combining clinical visual perception experimental data during implementation.

[0042] The dual-channel feature set output stage creates a data structure containing two fields: Field 1 stores the corrected light adaptation time constant (in milliseconds), and Field 2 stores the corrected dark adaptation time constant (in milliseconds). The data structure is written to the shared memory area at addresses 0x2000 - 0x2007 and stored in little-endian format. The write operation triggers a hardware interrupt, and the interrupt service routine reads and validates the data validity. In extreme light environments (>100,000 lux), the system forcibly enables parameter clipping protection: the light adaptation time is not less than 50 milliseconds, and the dark adaptation time does not exceed 3000 milliseconds.

[0043] The dynamic adaptation feature exception handling architecture includes three layers of fault tolerance: The first layer, when an abnormal illuminance sensor signal is detected (the same sampling value for 3 consecutive times), uses the previous valid parameter set; the second layer, when accessing the non-volatile memory fails, loads the firmware backup parameters (light adaptation 120 milliseconds, dark adaptation 2000 milliseconds); the third layer, when the proportional calculation overflows, forcibly outputs according to the boundary values. All abnormal events record error logs, and the log entries include a timestamp accurate to microseconds and an error type code.

[0044] The physiological parameter verification scheme is built based on a medical optical detection platform: Use a standard light source generator to simulate the change process of illuminance from 10 to 10,000 lux, and synchronously record the electroretinogram response of volunteers with a high-speed eye tracker. Optic nerve conduction delay data is obtained by testing 50 healthy subjects, where the light adaptation time range is 120 - 160 milliseconds for photopic vision and 1500 - 2200 milliseconds for scotopic vision. The deviation requirement between the output parameters of this system and the clinical test results is controlled within 15%, and it is verified through 200 sets of comparative tests.

[0045] Explanation of the core parameter setting principle: The selection of the photopic vision benchmark of 140 milliseconds is based on the median time of cone cell photochemical activation; the scotopic vision benchmark of 1800 milliseconds is based on the rhodopsin regeneration kinetic constant. The method for determining the proportionality factor is: Measure the critical flicker frequency at different change rates on a light intensity gradient test platform, and inversely deduce the optimal proportionality coefficients of 0.04 and 0.06 in combination with the pupil diameter change model. The temperature compensation coefficient is formulated based on the relationship model between the semiconductor carrier mobility and temperature.

[0046] The hardware platform configuration requirements are: a processor with a floating-point unit (main frequency ≥50 MHz) is required, and 12KB of memory is allocated for data processing. The timing indicators are measured by a logic analyzer: the full process from sampling to trend determination ≤250 μs, and the temperature compensation calculation ≤50 μs. Environmental adaptability requirements: At an ambient temperature of -40°C, a +20% margin adjustment of the reference value needs to be enabled; at a high temperature of 85°C, a 90% attenuation coefficient is used.

[0047] All numerical units strictly adopt international symbols: time in ms, illuminance in klx, and rate of change in klx / s. Parameter recording rule: Floating-point numbers are retained with three significant figures, and the order of structure fields is fixed with light adaptation first and dark adaptation second. The calibration period is set to perform full-automatic calibration every 30 days: Input a gradient signal of 500 klx / s through a standard light source, verify the deviation degree of the output time constant of the system, and automatically update the proportional factor and save the calibration record when the deviation exceeds 5%.

[0048] S4. Perceive and correct the sensitivity of the light fluctuation frequency component according to the dynamic visual adaptation characteristics to generate an equivalent frequency of perceived sensitivity. The specific implementation is as follows: The operation process of extracting the light adaptation time constant and dark adaptation time constant from the dynamic visual adaptation characteristic parameter set is as follows: The microcontroller directly accesses the 8-byte storage area starting from memory address 0x2000. The first 4 bytes of this area store the light adaptation time constant, with the data format being IEEE754 single-precision floating-point number and the unit being ms; the last 4 bytes store the dark adaptation time constant, with the same format and unit. After the data is read, integrity verification is performed: Verify whether the numerical range conforms to the valid intervals of 50 ms to 500 ms (light adaptation) and 500 ms to 3000 ms (dark adaptation). The verification algorithm uses cyclic redundancy check calculation, and the generating polynomial is represented in hexadecimal notation as 0x11021. When the data exceeds the valid range, it is automatically replaced with the default value stored at address 0xFF00 (100 ms for light adaptation and 2000 ms for dark adaptation), and at the same time, the exception code 0x01 is recorded in the non-volatile memory.

[0049] The calculation process of converting the light adaptation time constant to the photopic perception gain factor is executed in a dedicated circuit: First, load the input value into the floating-point arithmetic unit register. The conversion function is defined as "2.0 divided by the sum of 1 and the value of the negative power of the natural constant e to the power of 0.00001 times the light adaptation time constant". The natural constant e takes the fixed value of 2.71828. The calculation result is temporarily stored in the cache register. The environmental temperature correction reads the temperature sensor data in real time, applies a correction factor of 1.0 at the reference temperature of 25 °C, and increases the correction amount by 0.005 for each 1 °C increase. The final gain factor is limited between 0.8 and 1.8, and the boundary value clamping mechanism is enabled when it exceeds the range.

[0050] The processing steps of the dark adaptation time constant input time integrator are as follows: The time integrator configures the discrete integration step size to 50 ms. The calculation process is as follows: The total time is equally divided into several segments according to the step size, and for each segment, the integration operation "e to the power of negative t divided by the dark adaptation time constant times the step size parameter" is performed, where t represents the starting time of that time segment. The integration results of each segment are accumulated to obtain the scotopic cumulative effect factor. When the dark adaptation time constant exceeds 2000 ms, the hardware accelerator (implemented based on the CORDIC algorithm) is automatically enabled to ensure that the calculation period does not exceed 500 ms. The calculation result is stored at the memory address 0x3000 in the format of a single-precision floating-point number.

[0051] The two-way frequency domain modulation operation is implemented according to the following procedure: The optical fluctuation frequency components are respectively input into two independent processing channels. The high-frequency enhancement channel applies a second-order Butterworth filter, and the gain parameter of this filter is set to the current photopic perception gain factor value, and the cut-off frequency is fixed at 15 Hz. The low-frequency suppression channel applies an infinite impulse response filter, and the filter coefficient is set to the scotopic cumulative effect factor multiplied by 0.01, and the stopband frequency is set to 3 Hz. The output signals of the two channels are input into a complex signal synthesizer: the signal of the high-frequency channel is connected to the real part input terminal, and the signal of the low-frequency channel is connected to the imaginary part input terminal. The complex signal synthesizer outputs a complex-form signal to the buffer address 0x4000.

[0052] The final stage of generating the equivalent frequency of perceptual sensitivity is executed as follows: Read the complex signal from the buffer and calculate the modulus value of this complex number (the square root of the sum of the squares of the real part and the imaginary part). The modulus value calculation process uses the Newton iteration method and iterates three times to meet the accuracy requirements. The phase continuity detector compares the angle change amount between the current output and the previous output. When the angle difference exceeds 0.5 radians, five-point linear interpolation smoothing processing is enabled: Linear interpolation is performed within a continuous five-sampling-point window, and the interpolation step size is set to 0.1 radians. The final result is quantized to three significant figures and stored at the memory address 0x5000. The phase continuity monitoring data is recorded in the monitoring register at the address 0x5010, and the 3rd bit represents the phase anomaly state.

[0053] The technical verification plan is implemented according to the following standards: Use a programmable signal generator to input a 10 Hz standard optical fluctuation frequency. Test three scenario combinations: The expected output of scenario combination 1 (light adaptation 130 ms / dark adaptation 1500 ms) is 13.5 Hz ± 0.5 Hz; the expected output of scenario combination 2 (light adaptation 500 ms / dark adaptation 2300 ms) is 7.2 Hz ± 0.3 Hz; the expected output of scenario combination 3 (light adaptation 100 ms / dark adaptation 1800 ms) is 11.8 Hz ± 0.4 Hz. The verification device uses a 200 MHz bandwidth oscilloscope, and the probe is connected to the output terminal of the complex signal synthesizer. The test requires that the phase jump is less than 0.1 radians for three consecutive measurements.

[0054] Description of the basis for setting core parameters: The cut-off frequency of the Butterworth filter at 15 Hz is set according to the ISO 13489 standard of the International Organization for Standardization. The value of the natural constant e, which is 2.71828, is defined using the standard mathematical constant library. The five-point linear interpolation step size of 0.1 radian is determined according to the minimum phase resolution requirement of the Shannon sampling theorem. The temperature correction coefficient with an adjustment of 0.005 per °C is sourced from the experimental data of the temperature drift of the optoelectronic conversion device.

[0055] Exception handling executes a three-order strategy: In the first order, when the input parameters exceed the limit, they are forcibly replaced with the default value combination stored at address 0xFF00. In the second order, timeout monitoring is processed: When the light adaptation conversion exceeds 100 μs or the dark adaptation integration exceeds 500 ms, the hardware watchdog reset is triggered. In the third order, after the phase anomaly accumulates three times, the historical average value output mode is automatically switched (taking the average of the previous ten valid outputs). All exception events record log entries: Each log occupies 16 bytes (4-byte timestamp + 4-byte error code + 8-byte additional information).

[0056] Verification platform configuration requirements: The main control chip needs to have a floating-point unit (such as the ARM Cortex-M4F architecture), and the main frequency is not less than 50 MHz. The minimum memory allocation is 30 bytes: 8 bytes for input parameters, 12 bytes for intermediate variables, and 10 bytes for output data. Execution time limit constraint: The entire process is completed within 300 μs, including 80 μs for gain calculation, 120 μs for integral operation, 50 μs for frequency domain modulation, and 50 μs for output generation.

[0057] Calibration and maintenance procedures: Perform online calibration every 90 days. Input a standard 10 Hz test signal through the maintenance interface, and capture the output waveform using a storage oscilloscope. Automatically adjust the five-point interpolation parameters according to the phase continuity index (less than 0.1 radian jump). Before writing the new parameters, perform a dual-region verification: The data in the backup region and the main region must be consistent before they can take effect. The calibration record includes the old parameters, new parameters, verification values, and timestamps.

[0058] Production test standard: Run the test sequence continuously for 48 hours in a high-temperature environment of 85 °C. Record a set of output data every 2 hours, and the frequency fluctuation range is required to be less than 0.2 Hz. The passing rate requirement for the phase continuity index is more than 99%. The final test report includes the temperature curve, frequency output curve, and phase jump histogram data.

[0059] S5. When the equivalent frequency of the perception sensitivity is lower than the lower limit value of the human eye's visual sensitivity frequency, increase the initial derating rate until the newly generated equivalent frequency of the perception sensitivity is not lower than the lower limit value of the human eye's visual sensitivity frequency, and obtain the optimized derating rate. The specific implementation is as follows: The implementation process of establishing the comparison relationship between the current perceived sensitivity equivalent frequency and the lower limit value of the human eye visual sensitivity frequency is as follows: The microcontroller directly reads the perceived sensitivity equivalent frequency value from the memory address 0x5000. This value is stored in floating-point format with the unit of Hz. At the same time, the lower limit value of the human eye visual sensitivity frequency is loaded from the address 0xA000. The two values are transmitted to the hardware comparator unit for differential mode operation: specifically, calculate the difference between the perceived sensitivity equivalent frequency minus the lower limit value of the human eye visual sensitivity frequency. When the difference is less than -0.01 Hz, the comparator outputs a low-level signal; otherwise, it outputs a high-level signal. This level state is mapped to the 7th bit of the system status register: a bit value of 0 indicates below the threshold, and a bit value of 1 indicates meeting the requirements. The state change triggers a 3-level priority interrupt request through the interrupt controller and is responded to by the interrupt service program within 5 μs.

[0060] The operation process of setting the initial derating rate change step value is as follows: Under the condition that the 7th bit of the status register is 0, the processor accesses the step configuration table starting from the flash address 0x8000. Each row record of this configuration table contains 5 fields: the power level range is 0 - 200W, the reference rate unit is % / s, the minimum step value, the maximum step value, and the adaptive coefficient range is 0.01 - 0.1. The actual output power value obtained by the power detection circuit is used to match the closest power level row record. The calculation process uses the formula: final step value = minimum step value + adaptive coefficient × (reference rate - current rate). The calculation result is written into the dedicated register at the address 0x7000 in 16-bit fixed-point number format with a precision of 0.001% / s.

[0061] The execution steps for increasing the derating rate value are as follows: First, read the current derating rate value from the address 0x6000 in single-precision floating-point format. Then, obtain the step value from the address 0x7000. Perform an addition operation in the floating-point arithmetic unit: new rate value = current rate + step value. The calculation result is temporarily stored in the buffer area at the address 0x7100. Then, perform a boundary validity check: when the new rate value > 30% / s, it is forced to be set to 30%; when < 1% / s, it is set to 1%. The data passing the check will be updated to the derating rate storage location at the address 0x6000. The entire process is monitored by the hardware timer, and if it takes more than 50 μs, a timeout alarm will be triggered.

[0062] The operation of regenerating the optical fluctuation frequency component is strictly performed according to Step 2: The input parameters obtain the optical flux response delay time constant in milliseconds from address 0x2004, and obtain the new derating rate value in % / s from address 0x6000. The calculation process defined in Step 2 of the original method is fully executed: access the preset conversion model → calculate based on the inverse relationship → output the optical fluctuation frequency component to the storage location at address 0x3000. This process enables a 200 μs timeout protection mechanism and uses a dedicated hardware coprocessor to ensure real-time requirements. The newly generated component value directly overwrites the previous result, and historical data is not retained.

[0063] The operation of generating a new equivalent frequency of perceptual sensitivity fully reuses Step 4: The input parameters include the optical fluctuation frequency component at address 0x3000, the light adaptation time constant at address 0x2008, and the dark adaptation time constant at address 0x200C. It is strictly executed according to the process defined in Method Step 4: extract parameters → calculate the gain factor and integral effect factor → perform two-way frequency domain modulation → generate a phase-continuous output. The result data is written to the newly allocated buffer at address 0x5100. All exception handling mechanisms of the original Method Step 4 are inherited, and all error events are recorded in the independent log partition at address 0xF000 segment. The single-operation time limit is restricted to 300 μs.

[0064] The closed-loop control process of the second comparison is as follows: Read the new equivalent frequency value of perceptual sensitivity from address 0x5100 and input it into the comparator unit together with the lower limit value at address 0xA000. The same differential algorithm as the initial comparison is adopted: it is determined that optimization is still required when the new value - lower limit value < -0.01 Hz. The system incorporates a debounce mechanism design: It is required that the comparison results are all low for 3 consecutive times to confirm the status. The status register bit 7 is updated in real time, and the status change edge re-triggers the interrupt request loop. At the same time, the value of the loop counter at address 0x7200 is automatically incremented by 1.

[0065] The execution procedure configuration of the operation loop is as follows: The system sets an upper limit of 5.0 loop times. Each loop contains sequential operations: judge the status register bit → calculate the step value → increase the rate → regenerate the component → generate a new equivalent frequency → perform the second comparison. The overall time consumption of a single loop is controlled within 1000 μs and is monitored by the watchdog timer throughout the process. When the loop count reaches 5.0 times, all operations are forcibly terminated regardless of the current status result. In a low-temperature environment of -40 °C, the single-loop time limit is relaxed to 1200 μs.

[0066] The control strategy for terminating the operation loop is as follows: when the 7th bit of the status register becomes 1, the loop control unit executes the termination sequence: first, freeze the loop counter at address 0x7200; then disable the function of the status register update circuit; finally, clear all relevant interrupt flags. At the same time, send a ready signal to the power management unit. In a high-temperature environment of 85°C, an operation delay compensation of 50 ns is added. The system records the effective number of loops in the log storage area at address 0x8100.

[0067] The final operation for outputting the optimized derating rate is: read the final derating rate value from address 0x6000, and after format conversion, write it into the optimized rate storage area at address 0x8000. The data is stored in single-precision floating-point format, retaining 3 significant figures. Update the 0th bit of the global status register to high level, indicating that the optimization process is completed. Perform secondary data verification before output: confirm that the value is within the valid range of 1% - 30%, otherwise enable the closest boundary value for replacement. The final result is transmitted to the power execution standby via the control bus.

[0068] The exception handling framework includes three levels of protection: the primary protection forces the output of a preset value of 10% / s when the loop count reaches the upper limit of 5.0 times; the intermediate protection skips the current iteration when the single-loop timeout is 1000 μs; the advanced protection switches to the golden section method optimization when 5 exceptions are continuously triggered within 10 minutes. All exceptions are recorded in the partition at address 0xF000, and each log occupies 16 bytes of storage space: 4-byte timestamp + 4-byte error code + 8-byte snapshot of key parameters.

[0069] The specific technical verification plan is as follows: build a test platform and set the initial equivalent frequency to 8 Hz and the lower limit of human eye sensitivity to 10 Hz. Use a 200 MHz logic analyzer to monitor the whole process: record the changes in the rate value and equivalent frequency value of each loop. Verify the core indicators: reach the target above 10 Hz within 3 - 4 loops; the final rate falls within the range of 15% - 25% / s. Perform a temperature cycle test: continuously cycle 10 times from -40°C to 25°C to 85°C, confirm that the function is normal and the maximum number of loops ≤ 6 times. The success rate index requires that more than 99% of the tests pass.

[0070] The basis for parameter setting is as follows: the adaptive coefficient of 0.05 is calibrated by the gradient descent method: the optimal value is measured at the 100 W power point experiment. The loop upper limit of 5.0 times is based on the worst-case test result: a 3 Hz gap requires 5 iterations to complete. The 1% rate lower limit ensures that the power supply never enters the sleep state. The 3-time determination in the anti-shake mechanism is determined based on the test data of the signal stability time.

[0071] The production test protocol stipulates that full-range verification is performed during the product aging test stage: set the initial equivalent frequency in the range of 6Hz to 9.9Hz, with a step of 0.1Hz for test points. Each test point is executed for 100 cycles: the pass rate requirement is >99%; the average number of iterations is 3.5 times; the maximum derating rate is ≤27% / s. Finally, a test report is generated, including a convergence curve distribution map and abnormal event statistics.

[0072] Implementation of the resource monitoring mechanism: The resource counter works throughout the loop process: the clock consumption per iteration is ≤20,000 cycles; the memory increment is controlled within 16B; the peak processor load is 70%. When the high-temperature environment is >85°C, the time limit constraint is relaxed by 20%. The watchdog timer is set to a reset cycle of 3ms, fully covering the worst-case operation duration of 5ms.

[0073] S6. Perform the output power derating operation according to the optimized derating rate. The specific implementation is as follows: The operation process of loading the value stored in the dedicated storage area for the optimized derating rate and converting it into the waveform parameter of the power control signal is as follows: The processor accesses the optimized derating rate value at the address 0x8000. This value is stored in the single-precision floating-point format, with the unit of % / s. The read value is input into the waveform parameter generation unit, and the core of this unit adopts a 32-bit computing architecture. The conversion algorithm is defined as: the duty cycle change rate = the optimized derating rate × the power conversion coefficient. The power conversion coefficient is determined according to the power supply topology: 0.01 for the buck converter circuit, 0.008 for the boost converter circuit, and 0.009 for the buck-boost converter circuit. The calculation result is converted into a 16-bit pulse width modulation control parameter, where the high 8 bits store the initial duty cycle value, and the low 8 bits store the change step value. The parameter set is written to the register address 0x9000 in the format of a two-byte data packet.

[0074] The specific process of configuring the driving timing sequence of the power switch tube is as follows: Read the pulse width modulation control parameter from the address 0x9000 and decompose it into two independent variables: the initial duty cycle and the change step value. The driving timing sequence is designed as a four-stage structure: stage 1 sets the dead time to 50ns; stage 2 configures the maximum conduction time to 2μs; stage 3 defines the minimum turn-off time to 300ns; stage 4 programs the change step cycle to 10μs. The timing parameters are stored in the area of the dedicated timer configuration register addresses 0x9200 - 0x9203. After the configuration takes effect, the hardware pulse width modulation generator automatically generates a waveform according to the timing sequence, and the output base frequency is set to 100kHz ± 100Hz.

[0075] The implementation path for transmitting the pulse-width modulation waveform to the gate of the power switch tube through the isolation drive circuit is as follows: The pulse-width modulation waveform output pin is connected to the input side of the high-speed optocoupler isolator, and an industrial standard model high-speed optocoupler device is selected. The output side of the isolator drives the push-pull amplifier circuit, and the push-pull metal-oxide-semiconductor field-effect transistor adopts a dual-tube complementary structure. The gate drive resistor is configured as 10 Ω, the rise time control target is within 80 ns, and the fall time control target is within 60 ns. The drive power is monitored in real time through a 0.5 Ω sampling resistor. When the drive current exceeds the preset threshold, the overcurrent protection interrupt is immediately triggered, and the interrupt priority is set to level 2.

[0076] The monitoring mechanism for real-time monitoring of the change gradient of the output power is as follows: The output bus voltage is sampled through a resistor voltage division circuit, and the typical voltage division ratio is set to 51:1; the output current is detected through a magnetic balance Hall effect sensor. The collected data is transmitted to the processor at a sampling frequency of 10 kHz, and the real-time power is calculated using the basic formula of instantaneous voltage value × instantaneous current value. The change gradient is calculated using the three-point difference method: (the current power value - the power value 3 ms ago) ÷ 3 ms time interval. The gradient calculation result is stored in the dedicated storage location at address 0x9300, with the unit of mW / ms. This value is updated every 100 μs.

[0077] The control logic for adjusting the duty cycle change rate of the pulse-width modulation waveform is as follows: Read the current output power change gradient value and compare it with the optimized derating rate target value (mW / ms) after unit conversion. When the actual gradient value < 90% of the target value, increase the duty cycle change step value by 10%; when the actual gradient value > 110% of the target value, decrease the duty cycle change step value by 10%. The adjustment signal is implemented by writing to register address 0x9210, which is mapped to the dynamic step register of the pulse-width modulation generator. The adjustment operation is required to be completed within 5 μs, and the hardware automatically maintains the waveform phase continuity.

[0078] The processing rule when the deviation between the output power change gradient and the optimized derating rate exceeds the allowable range is as follows: The allowable range is set to the ±15% interval of the optimized derating rate target value. When exceeding this range, activate the three-level fine-tuning compensation mechanism: The first-level compensation adjusts the duty cycle step value by 20%; the second-level compensation modifies the timing parameter to extend the period by 10 μs; the third-level compensation reduces the pulse-width modulation frequency to 80 kHz. The compensation rules are stored in the lookup table starting address 0x9400, and a higher-level compensation is enabled for every 5% increase in the deviation. The compensation signal is transmitted to the control core through interrupt priority 4.

[0079] The implementation details of the startup duty cycle fine-tuning compensation mechanism are as follows: The compensation unit reads the current deviation value and calculates the compensation amount = deviation value × 0.8 coefficient. The compensation operation sequence is: First, multiply the duty cycle change step value by 1.2 coefficient; then delay for 50 μs to monitor the system response; finally, evaluate whether the gradient value after compensation is improved. The evaluation result is stored in the monitoring area at address 0x9500 for decision-making on whether to enable more advanced compensation. The compensation mechanism is limited to a maximum of 3 levels, and when exceeding 3 levels, the system alarm state is automatically triggered.

[0080] The stable determination condition after confirming that the output power is stable at the target derating value is: the change range of 50 consecutive power sampling values ≤ ±2%; at the same time, the power gradient value remains < 5% of the optimized derating rate for 100 ms. The stable state is monitored by a dedicated comparator, and the output pin is connected to the 5th bit of the system status register. When this bit jumps from low level to high level, it indicates that the system enters the stable state.

[0081] The last operation to lock the current drive parameters to maintain power output is: The lock sequence performs three atomic operations: freeze the pulse width modulation timer configuration register; disable the dynamic step adjustment function; fix the output drive parameters to the non-volatile storage area address 0x9800. The locked state continuously monitors environmental changes: When it is detected that the environmental temperature changes by more than ±10°C or the input voltage fluctuates by more than ±15%, the lock is automatically released and recalibrated. During the locked period, the power fluctuation control index requires a maximum value ≤ ±1.5%.

[0082] The fine-tuning compensation exception handling process is as follows: When the gradient improvement rate < 20% after a single compensation operation, record the compensation failure event code 0xB1; when the compensation fails to meet the expected effect for 3 consecutive times, switch to the alternate compensation table address 0x9900; after 10 cumulative compensation failures, activate the safety mode to fix the output at 60% of the rated power. All exception events are written into the ring log cache address space from 0x9A00 to 0x9AFF, and each log record contains 16 bytes of information.

[0083] The specific implementation of the technical verification test plan: Set the initial power to 100W and the optimized derating rate to 10% / s on the programmable electronic load test bench. Use a four-channel oscilloscope to monitor key nodes: Channel 1 tracks the gate drive waveform; Channel 2 captures the output power gradient; Channel 3 records the duty cycle change curve. The core test index requirements are: power gradient tracking error ≤ ±5%; compensation response time < 80 μs; stable state establishment time < 500 ms; steady-state power fluctuation ≤ 1.5%. In the high-temperature 85°C test environment, the index is allowed to be relaxed to a tracking error ≤ ±8%.

[0084] Compensation parameter setting basis description: The first-level compensation coefficient of 0.8 is determined by load step response experiment: optimized in 30% to 70% load mutation test. The three-level compensation mechanism design is based on the thermal response characteristics of the power switch tube: the first level corresponds to the electrical response stage, the second level corresponds to the heat transfer delay stage, and the third level corresponds to the structural heat capacity saturation stage. The allowable deviation range of ±15% is formulated according to the international standard for dynamic response of switching power supplies.

[0085] The production test specification is clear: each finished product performs 3 groups of derating test sequences: Group 1 optimization rate 10% / s; Group 2 20% / s; Group 3 5% / s. Each group of tests measures 5 key parameters: initial overshoot ≤8%; stabilization time <600ms; gradient error ≤7%; compensation trigger times <4; steady-state error ≤2%. Unqualified products will activate the maintenance code 0xC1 and return to the compensation parameter calibration process for re-calibration.

[0086] Hardware resource monitoring requirements: During the drive parameter locking period, the system resource utilization rate is 30%, of which the pulse width modulation generator accounts for 15%, the monitoring circuit accounts for 10%, and the compensation unit accounts for 5%. Within the input voltage range of 180V to 240V, the dynamic adjustment function consumes 2.5mJ of energy for a single operation. The heat dissipation design meets the most severe working conditions: When the load is continuously reduced at 90%, the junction temperature of the metal oxide semiconductor field effect transistor is <110℃.

[0087] This embodiment dynamically models the light and dark adaptation characteristics of the human eye retina as a programmable time parameter, and designs a dual-channel visual perception path to handle the gain and integral effects respectively; at the control strategy level, the power derating process is converted into an equivalent frequency optimization problem, and the power adjustment trajectory is constrained in real time through a closed-loop iteration mechanism of the equivalent frequency of the perception sensitivity, so as to achieve a light output transition that is not perceptible to the human eye; at the system integration level, a dynamic visual adaptation characteristic parameter set is set as a cross-domain control center, so that the light source response characteristics and the power supply power adjustment produce a synergistic coupling effect. Specifically in the execution link, the state judgment method based on the sequence extreme position overcomes the lag of the simple amplitude judgment criterion; the physiological sensitive frequency threshold is converted into a real-time optimization criterion for the derating rate, breaking through the path dependence of the traditional over-temperature protection on the temperature threshold; in the power execution stage, a gradient tracking compensation architecture is pioneered to solve the stability control problem of the variable rate derating process. This cross-domain collaborative mechanism that integrates visual physiological models, adaptive frequency optimization and power closed-loop control eliminates flicker perception while ensuring thermal safety goals.

[0088] Embodiment 2: Figure 2 The structural schematic diagram of the LED power supply safety control system with over-temperature protection function of the present invention is given. The LED power supply safety control system with over-temperature protection function includes the following modules: A parameter acquisition module, which is used to monitor the temperature value of the key parts of the LED power supply in real time. When the temperature value exceeds the set protection threshold, it acquires the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency. A component calculation module, which is used to calculate the optical fluctuation frequency component corresponding to the current initial derating rate according to the optical flux response delay time constant. An adaptation analysis module, which is used to detect the change trend of the ambient light source intensity and analyze the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity. A perception correction module, which is used to correct the perception sensitivity of the optical fluctuation frequency component according to the dynamic visual adaptation characteristics to generate an equivalent frequency of perception sensitivity. A rate optimization module, which is used to increase the initial derating rate until the newly generated equivalent frequency of perception sensitivity is not lower than the lower limit value of the human eye visual sensitivity frequency when the equivalent frequency of perception sensitivity is lower than the lower limit value of the human eye visual sensitivity frequency, so as to obtain an optimized derating rate. A derating execution module, which is used to perform the output power derating operation according to the optimized derating rate.

[0089] The calculations involved in the embodiments are all dimensionless numerical calculations. The preset parameters and threshold selections in the calculations are set by those skilled in the art according to the actual situation.

[0090] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product.

[0091] Those of ordinary skill in the art can realize that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and invention constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0092] In addition, the functional modules in each embodiment of the present application can be integrated into one processing module, or each module can exist physically alone, or two or more modules can be integrated into one module.

[0093] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the devices or modules can be in an electrical, mechanical, or other form.

[0094] As described above, this is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0095] Finally: The above description is only the preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A safety control method for an LED power supply with an over-temperature protection function, characterized in that, It includes the following steps: S1. Monitor the temperature value of the key parts of the LED power supply in real time. When the temperature value exceeds the set protection threshold, obtain the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency; S2. Calculate the optical fluctuation frequency component corresponding to the current initial derating rate according to the optical flux response delay time constant; S3. Detect the change trend of the ambient light source intensity, and analyze the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity; S4. Correct the perception sensitivity of the optical fluctuation frequency component according to the dynamic visual adaptation characteristics to generate the equivalent frequency of the perception sensitivity; S5. When the equivalent frequency of the perception sensitivity is lower than the lower limit value of the human eye visual sensitivity frequency, increase the initial derating rate until the newly generated equivalent frequency of the perception sensitivity is not lower than the lower limit value of the human eye visual sensitivity frequency, and obtain the optimized derating rate; S6. Perform the output power derating operation according to the optimized derating rate.

2. The LED power supply safety control method with over-temperature protection function according to claim 1, characterized in that, Monitoring the temperature value of the key parts of the LED power supply in real time. When the temperature value exceeds the set protection threshold, obtaining the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency includes: Synchronously sample the junction temperature of the power switch tube and the surface temperature of the magnetic component of the LED power supply; When any sampled temperature value exceeds the set protection threshold three times in a row, it is determined that the over-temperature protection trigger condition is met; While triggering the over-temperature protection condition, obtain the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency.

3. The LED power supply safety control method with over-temperature protection function according to claim 2, characterized in that, Obtaining the pre-stored optical flux response delay time constant and the lower limit value of the human eye visual sensitivity frequency specifically includes: Obtain the LED light source package model code of the current drive circuit, query the light source characteristic mapping table pre-stored in the non-volatile memory according to the LED light source package model code, and extract the corresponding optical flux response delay time constant from the light source characteristic mapping table; Read the current lighting scene classification identifier through the scene recognition interface, and retrieve the lower limit value of the human eye visual sensitivity frequency associated with the corresponding scene from the visual perception parameter database according to the lighting scene classification identifier.

4. The LED power supply safety control method with over-temperature protection function according to claim 1, wherein, Calculating the optical fluctuation frequency component corresponding to the current initial derating rate according to the optical flux response delay time constant includes: Read the initial derating rate stored in the microcontroller of the current drive circuit; Obtain the current effective value of the optical flux response delay time constant; Establish a conversion model based on the inverse relationship between the optical flux response delay time constant and the optical fluctuation frequency component; Input the initial derating rate into the conversion model for operation; Output the optical fluctuation frequency component value corresponding to the current initial derating rate.

5. The LED power supply safety control method with over-temperature protection function according to claim 1, characterized in that, Detecting the change trend of the ambient light source intensity, and analyzing the dynamic visual adaptation characteristics based on the change trend of the ambient light source intensity includes: Detect the illuminance measurement value sequence of the current ambient lighting light source at three consecutive sampling time points; Identify the position order of the maximum measurement value and the minimum measurement value in the illuminance sequence; Determine the illuminance change direction as an increasing trend or a decreasing trend according to the position order; When the change direction is an increasing trend, select the benchmark adaptation time dominated by photopic vision from the pre-set physiological parameter library; When the change direction is a decreasing trend, select the benchmark adaptation time dominated by scotopic vision from the pre-set physiological parameter library; Based on the combination of the absolute value of the illumination change rate and the change direction to correct the reference adaptation time: shorten the light adaptation time constant according to the change rate ratio under the increasing trend, and extend the dark adaptation time constant according to the change rate ratio under the decreasing trend; Output a two-channel dynamic visual adaptation characteristic set carrying directional features.

6. The LED power supply safety control method with over-temperature protection function according to claim 1, characterized in that, Perform perception sensitivity correction on the light fluctuation frequency components according to the dynamic visual adaptation characteristics to generate an equivalent frequency of perception sensitivity, including: Extract the light adaptation time constant and the dark adaptation time constant from the dynamic visual adaptation characteristic parameter set; Input the light adaptation time constant into the physiological response conversion function to calculate the photopic perception gain factor; Input the dark adaptation time constant into the time integration operator to calculate the scotopic cumulative effect factor; Perform two-way frequency domain modulation on the light fluctuation frequency components; Combine the modulation results to generate a phase-continuous equivalent frequency output value of perception sensitivity.

7. The LED power supply safety control method with over-temperature protection function according to claim 6, characterized in that, The two-way frequency domain modulation includes: the photopic perception gain factor acts to enhance the high-frequency response of the frequency components; the scotopic cumulative effect factor acts to suppress the low-frequency fluctuations of the frequency components.

8. The LED power supply safety control method with over-temperature protection function according to claim 1, characterized in that When the equivalent frequency of perception sensitivity is lower than the lower limit value of the human eye visual sensitive frequency, increase the initial derating rate until the newly generated equivalent frequency of perception sensitivity is not lower than the lower limit value of the human eye visual sensitive frequency, including: Establish a comparison relationship between the current equivalent frequency of perception sensitivity and the lower limit value of the human eye visual sensitive frequency; When the comparison result shows that it is lower, set the initial derating rate change step value; Increase the current derating rate value according to the initial derating rate change step value; Regenerate the light fluctuation frequency components based on the increased derating rate value; Perform perception sensitivity correction operation on the regenerated light fluctuation frequency components to generate a new equivalent frequency of perception sensitivity; Compare the newly generated equivalent frequency of perception sensitivity with the lower limit value of the human eye visual sensitive frequency again; Repeat the operation cycle of increasing the derating rate and regenerating and comparing; When the newly generated equivalent frequency of perception sensitivity reaches not lower than the lower limit value of the human eye visual sensitive frequency, terminate the operation cycle; Record the effective derating rate value at this time as the output of the optimized derating rate.

9. The LED power supply safety control method with over-temperature protection function according to claim 1, wherein, Perform the output power derating operation according to the optimized derating rate, including: Load the value stored in the dedicated storage area of the optimized derating rate and convert it into the waveform parameters of the power control signal; Configure the driving timing sequence of the power switch tube and generate a pulse width modulation waveform according to the driving timing sequence; Transmit the pulse width modulation waveform to the gate of the power switch tube through the isolation driving circuit; Monitor the change gradient of the output power in real time and adjust the duty cycle change rate of the pulse width modulation waveform; When the deviation between the output power change gradient and the optimized derating rate exceeds the allowable range, start the duty cycle fine-tuning compensation mechanism; After confirming that the output power is stable at the target derating value, lock the current driving parameters to maintain the power output.

10. An LED power supply safety control system with an over-temperature protection function, which is used to implement the LED power supply safety control method with an over-temperature protection function described in any one of claims 1-9, characterized in that, Include the following modules: The parameter acquisition module is used to monitor the temperature value of the key parts of the LED power supply in real time. When the temperature value exceeds the set protection threshold, obtain the pre-stored light flux response delay time constant and the lower limit value of the human eye visual sensitive frequency; The component calculation module is used to calculate the light fluctuation frequency components corresponding to the current initial derating rate according to the light flux response delay time constant; An adaptation analysis module, which is used to detect the change trend of the environmental light source intensity and analyze the dynamic visual adaptation characteristics based on the change trend of the environmental light source intensity; A perception correction module, which is used to correct the perception sensitivity of the light fluctuation frequency component according to the dynamic visual adaptation characteristics and generate an equivalent frequency of perception sensitivity; A rate optimization module, which is used to increase the initial derating rate until the newly generated equivalent frequency of perception sensitivity is not lower than the lower limit value of the human eye visual sensitivity frequency when the equivalent frequency of perception sensitivity is lower than the lower limit value of the human eye visual sensitivity frequency, so as to obtain an optimized derating rate; A derating execution module, which is used to perform an output power derating operation according to the optimized derating rate.

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