Microwave detection multi-color temperature cylinder lamp and pulse width modulation intelligent control method thereof

Abstract

The present application relates to the technical field of lighting, in particular to a microwave detection multi-color temperature down lamp and a pulse width modulation intelligent control method thereof. The pulse width modulation intelligent control method of the microwave detection multi-color temperature down lamp comprises the following steps: obtaining a target brightness of the down lamp; obtaining a color temperature demand of a user; determining a target brightness of each LED lamp bead in the down lamp according to the target brightness and the color temperature demand, wherein the color temperatures of at least two lamp beads are different; and controlling each LED lamp bead to emit light with the target brightness. The present application can realize high-precision matching of the brightness and the color temperature of the down lamp.

Description

Technical Field

[0001] This invention relates to the field of lighting technology, and in particular to a microwave-detected multicolor temperature downlight and its pulse width modulation intelligent control method. Background Technology

[0002] Currently, downlights typically use a single color temperature and fixed power light source, which can only work at a certain fixed color temperature and cannot meet the diverse needs of different scenarios and users for color temperature and brightness.

[0003] In addition, to achieve energy-saving goals, infrared and sound-sensing downlights are currently used to detect human activity and control the downlights to turn on based on that activity. However, infrared sensors have limited sensing distance and angle, are greatly affected by the environment, dust, and temperature, and the sensor head needs to be exposed, making installation inconvenient and aesthetically unappealing. Sound sensors, on the other hand, have a sensing distance that depends on the sound emitted by the object, are easily interfered with by ambient noise, and cannot be accurately triggered in certain scenarios. Summary of the Invention

[0004] In view of this, the present invention provides a microwave detection multi-color temperature downlight and its pulse width modulation intelligent control method to solve the technical problem that existing microwave detection multi-color temperature downlights cannot meet the diverse needs of different scenarios and users for color temperature and brightness.

[0005] The technical solution adopted in this invention is:

[0006] In a first aspect, the present invention provides a pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights, characterized in that the method includes the following steps:

[0007] The target brightness of the downlight is obtained, wherein the downlight has multiple LED beads, and the target brightness of the downlight is the overall brightness of the downlight;

[0008] Obtain the user's color temperature requirements;

[0009] The target brightness of each LED bead in the downlight is determined based on the target brightness and the color temperature requirement, wherein at least two LED beads have different color temperatures;

[0010] Control each LED bead to emit light at the target brightness;

[0011] In obtaining the target brightness of the downlight, the user can obtain the overall brightness required by the user through the brightness adjustment switch, the user operation interface, or the preset scene mode.

[0012] Secondly, the present invention provides a microwave detection multi-color temperature downlight, including a first LED bead, a second LED bead, and a control circuit. The first LED bead and the second LED bead have different color temperatures. The control circuit is electrically connected to the first LED bead and the second LED bead respectively. The control circuit stores computer program instructions, and when the computer program instructions are executed by the processor, the method described in the first aspect is implemented.

[0013] Beneficial effects: The microwave-detected multi-color temperature downlight and the pulse width modulation intelligent control method of the microwave-detected multi-color temperature downlight of the present invention achieve high-precision matching between downlight brightness and color temperature by mapping the overall target brightness and user color temperature requirements to the precise output values ​​of each LED bead; relying on the coordinated driving of LED beads with different color temperatures, a smooth transition between two different color temperatures can be achieved, meeting the lighting needs of multiple scenarios; the on-demand allocation of driving current avoids energy waste caused by over-driving or under-driving, and improves the energy utilization efficiency of the equipment. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0015] Figure 1 This is a flowchart illustrating the pulse width modulation intelligent control method for multi-color temperature downlights according to the present invention.

[0016] Figure 2 This is a flowchart illustrating the method for controlling the light emission of each LED bead according to the present invention.

[0017] Figure 3 This is a flowchart illustrating the method for determining the target brightness of each LED bead according to the present invention.

[0018] Figure 4 This is a flowchart illustrating the method of controlling the illumination of a downlight based on the detection results of a microwave sensor according to the present invention.

[0019] Figure 5 This is a schematic diagram of the multi-color temperature downlight control circuit of the present invention;

[0020] Figure 6 This is the functional timing logic diagram of the multi-color temperature downlight of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Where there is no conflict, embodiments of the present invention and the various features thereof can be combined with each other, all of which are within the scope of protection of the present invention.

[0022] Example 1

[0023] like Figure 1 As shown in the figure, this embodiment provides a pulse width modulation intelligent control method for multi-color temperature downlights, the method including the following steps:

[0024] S1: Obtain the target brightness of the downlight;

[0025] The target brightness refers to the brightness of the downlight as desired by the user. Since the downlight has multiple LED beads, the target brightness is the overall brightness of the downlight, not the brightness of a single LED bead. Users can obtain the desired overall brightness of the downlight through a brightness adjustment switch, a user interface, or preset scene modes. The user interface includes, but is not limited to, adjustment knobs, touch panels, remote controls, and mobile apps.

[0026] S2: Obtain the user's color temperature requirements;

[0027] In this step, the system collects the user's preferred color temperature settings, typically presented as Kelvin (K) values ​​or levels such as warm white, natural white, and cool white. This embodiment allows users to set multiple different color temperature requirements as needed.

[0028] S3: Determine the target brightness of each LED in the downlight based on the target brightness and the color temperature requirement, wherein at least two LEDs have different color temperatures;

[0029] This step distributes the overall target brightness to LED beads of different color temperatures according to the color temperature ratio. On the one hand, it uses the brightness combination of multiple LED beads to achieve the overall target brightness of the downlight. On the other hand, it uses the ratio of the brightness of different LED beads to obtain the color temperature effect required by the user.

[0030] S4: Controls each LED to emit light at the target brightness.

[0031] This step independently drives each LED to emit light, and the brightness of each LED is the target brightness determined in the previous step.

[0032] like Figure 2 As shown, in this embodiment, S4: controlling each LED bead to emit light at the target brightness further includes:

[0033] S41: Determine the target current corresponding to each LED based on the target brightness of each LED;

[0034] In this step, the electro-optical conversion characteristic curves of each LED bead (such as the relationship between brightness and driving current) can be read in advance, and the target brightness value of each bead determined in step S3 can be substituted into the curve or lookup table algorithm to calculate the driving current required to achieve the luminous flux. If the luminous efficacy changes nonlinearly with the current, the system will also combine temperature compensation and aging correction models to correct the calculation results in real time to ensure that the output current accurately and stably corresponds to the required brightness.

[0035] S42: Adjust the duty cycle of each LED chip according to the target current of each LED chip;

[0036] This step combines the target drive current value for each LED calculated in the previous step with the maximum adjustable current range and PWM frequency parameters of the drive circuit, and converts the target current into the corresponding PWM duty cycle through table lookup or calculation. Specifically, the correspondence between the duty cycle and the target current can be obtained through polynomial fitting curves. Alternatively, it can be calculated as the ratio of the target current to the maximum current. To improve accuracy, real-time compensation based on temperature or voltage fluctuations can be added so that the subsequent PWM signal can accurately output the corresponding average current.

[0037] S43: Control the output current of the control circuit by outputting a pulse width modulation signal according to the duty cycle of the pulse width modulation.

[0038] In this step, the microcontroller converts the calculated PWM duty cycle into an actual digital pulse width modulation waveform. It then drives the switching transistor to connect and disconnect the LED's power supply circuit via the driver device, so that the LED receives the set current during the "on" period and stops supplying power during the "off" period. Because the frequency is high enough, the LED's light output is consistent with the average current. The control circuit can also have a built-in feedback or current detection module to monitor the average current in real time and fine-tune the PWM signal duty cycle to compensate for deviations caused by changes in power supply voltage or temperature, thereby accurately and stably achieving the target current output of each LED.

[0039] like Figure 3 As shown, in this embodiment, step S3: determining the target brightness of each LED in the downlight based on the target brightness and the color temperature requirement, wherein at least two LEDs have different color temperatures, further includes:

[0040] S31: Obtain the brightness ratio of each color temperature according to the color temperature requirements;

[0041] In this step, the system calls a pre-stored color temperature-brightness ratio mapping table or algorithm based on the obtained user color temperature requirements to convert the target color temperature value into the relative brightness ratio required by LED beads of different color temperatures, which serves as the basis for subsequent brightness allocation.

[0042] S32: Determine the target brightness of each LED bead based on the brightness ratio of each color temperature of the target brightness.

[0043] In this step, the system combines the overall target brightness value obtained in the previous step with the brightness ratio of each color temperature LED bead calculated in the previous step. By multiplying the overall brightness by its respective ratio coefficient, the system calculates the target brightness that each color temperature LED bead should output, and allocates the target brightness to the corresponding LED bead group or individual LED bead to form the input target of the subsequent drive current or PWM duty cycle. This ensures that LED beads of different color temperatures output in a coordinated manner according to a predetermined ratio, thereby achieving the overall brightness and color temperature effect set by the user.

[0044] like Figure 4 and Figure 5 As shown, in this embodiment, the method further includes:

[0045] S5: Detects whether there is human activity in the target area using a microwave sensor;

[0046] In this step, the microwave sensor periodically emits high-frequency electromagnetic waves at a preset transmission power and receives the reflected echo signal. When the Doppler frequency shift or phase change of the reflected signal exceeds the noise threshold, the controller determines that there is human activity, thereby providing a trigger basis for subsequent brightness adjustment.

[0047] S6: When human activity is detected, adjust the target brightness to the first brightness;

[0048] Upon detecting a movement signal, the system immediately updates the current overall brightness target value to the preset "first brightness" mode. In this mode, the LED lights are set to full brightness or high brightness. The system then quickly drives the LED beads to reach this brightness level by recalculating and sending the PWM duty cycle or current value to meet the lighting needs when people are active.

[0049] S7: If no further human activity is detected within the first duration after human activity is detected, adjust the target brightness to the second brightness.

[0050] After reaching the first brightness level, the system starts a timer and continuously monitors the sensor status. If no movement signal is detected within the set first duration, the area is considered to be idle. The brightness target is then switched to a lower second brightness mode, such as energy saving or night mode, and a smooth transition is achieved by adjusting the drive parameters.

[0051] S8: If no human activity is detected again during the second duration after the target brightness is adjusted to the second brightness, the downlight will be turned off.

[0052] After reaching the second brightness level, the system continues to monitor movement signals and starts the second-stage timer. If no human activity is detected within the second duration, a shutdown command is executed to reduce the LED drive current to zero and turn off the downlight, effectively reducing energy consumption when no one is present.

[0053] When adjusting brightness and color temperature simultaneously, the PWM duty cycle of the warm and cool light channels is often calculated and directly sent out independently. Because the duty cycle variation and response speed of each channel are inconsistent, the following problems can easily occur during dynamic adjustment:

[0054] Instantaneous color temperature shift: When brightness and color temperature change occur simultaneously, if the duty cycle of the warm and cool light channels is not adjusted synchronously, users may perceive a brief warm or cool color shift at a certain moment during the change process, resulting in a decline in visual experience.

[0055] Unsmooth transition: Jumping directly from the current duty cycle to the target duty cycle may cause obvious brightness jumps or flickers in the light output during the change process, especially noticeable in low-brightness scenes.

[0056] In this embodiment, step S42: determining the pulse width adjustment duty cycle corresponding to each LED bead based on the target current of each LED bead further includes:

[0057] S421: Obtain the target current of the LED beads to get the target duty cycle of each color temperature channel;

[0058] Among them, the target current refers to the expected driving current for a certain color temperature channel (such as the warm channel and the cold channel) under the given target brightness and color temperature requirements; the color temperature channel is the control channel that divides the LED combination with different related color temperatures into independent and controlled channels; the target duty cycle refers to the duty cycle command that should be output in order to achieve the target current of a certain channel within a given PWM control framework.

[0059] In practice, the target luminous flux or relative proportion of each color temperature channel can be obtained from the upstream allocation, and the target current of each channel can be calculated by combining the calibration curve of the current luminous flux duty cycle. The target duty cycle can then be calculated in reverse.

[0060] S422: Based on the difference between the target duty cycle and the current duty cycle, obtain the amount of duty cycle change that each channel needs to adjust.

[0061] Here, the target duty cycle refers to the duty cycle obtained from the previous step, used to instruct a certain color temperature channel to achieve the desired light output; the current duty cycle is the actual duty cycle of the channel when entering this step; the difference refers to the numerical difference between the target duty cycle and the current duty cycle; the duty cycle change is the adjustment amount and direction performed in subsequent stages to reduce this difference. First, the current duty cycle of each color temperature channel can be read, and the signed difference can be calculated with the corresponding target duty cycle. To reduce the impact of sampling jitter, it is preferable to take the moving average or median of the most recent control cycles for both the target and current duty cycles as a comparison benchmark, and set a dead zone threshold so that the change is zero when the absolute difference is below the threshold to avoid invalid fine-tuning. Subsequently, the signed difference is converted into the duty cycle change of the channel according to a preset proportional coefficient, and then pruned in conjunction with system constraints: including single-step upper limit, minimum resolution step size, effective duty cycle range, and directional monotonicity requirements (automatically truncated or changed to zero if the channel is close to the boundary). In multi-channel collaborative scenarios, the change amount can be uniformly shaped according to the channel weight or target ratio relationship. For example, the change amount can be scaled proportionally to maintain the feasibility of subsequent synchronous advancement. For low brightness ranges, a smaller upper limit of change amount can be selected to reduce the quantization step effect. After the above processing, the duty cycle change amount of each channel output is the normalized deviation metric used in subsequent steps.

[0062] S423: Select the color temperature channel with the largest duty cycle change as the reference adjustment channel;

[0063] The color temperature channel with the largest duty cycle change is selected as the benchmark adjustment channel. The aim is to use the channel with the "largest gap" as a reference to unify the progress rhythm of other channels. This establishes a time and amplitude benchmark for synchronous adjustment, avoiding proportional drift caused by multiple channels acting independently, and ensuring that subsequent channels progress around the same rhythm, with the duty cycle gradually converging towards the target.

[0064] S424: Based on the difference between the current target brightness and the preset brightness threshold, obtain the single-step adjustment amount and transition time of the reference adjustment channel;

[0065] Specifically, when the target brightness is lower than the brightness threshold, the single-step adjustment amount is positively correlated with the difference, and the transition time is negatively correlated with the difference; when the target brightness is higher than or equal to the brightness threshold, the single-step adjustment amount is negatively correlated with the difference, and the transition time is positively correlated with the difference.

[0066] Specifically, based on the difference between the current target brightness and the preset brightness threshold, the single-step adjustment amount and transition time of the reference adjustment channel are obtained, and a correlation is set for two different ranges: when the target brightness is below the threshold, the larger the difference, the larger the single-step adjustment amount and the shorter the transition time, which is used to maintain fine detail without excessive sluggishness in the low-brightness area; when the target brightness is above or equal to the threshold, the larger the difference, the smaller the single-step adjustment amount and the longer the transition time, which is used to control the propulsion intensity and rhythm in the high-brightness area. Through this segmented relationship, paired parameters of amplitude and duration are provided for subsequent synchronous adjustments.

[0067] S425: Based on the duty cycle change of the reference adjustment channel, combined with the single-step adjustment amount and transition time, determine the synchronous adjustment step size of all the color temperature channels;

[0068] Based on the duty cycle change of the baseline adjustment channel, combined with the single-step adjustment amount and transition time, the synchronization adjustment step size of all color temperature channels is determined. Using the single-step advancement of the baseline channel as the benchmark amount, the step size of the remaining channels is calculated according to the target ratio or predetermined synchronization rules, so that each channel advances at a consistent pace in each stage; for the channel that reaches the target or boundary first, the step size is automatically reduced to zero, while other channels continue to execute, thereby maintaining consistent advancement and boundary safety as a whole.

[0069] S426: Based on the synchronous adjustment step size and the duty cycle change of each color temperature channel, a phased duty cycle change sequence is obtained. The phased duty cycle change sequence includes several adjustment stages executed sequentially. Each adjustment stage includes at least the target duty cycle of the channel and the stage execution time for that stage.

[0070] S427: During the transition period, the current duty cycle is adjusted according to the phased duty cycle change sequence.

[0071] Based on the synchronous adjustment step size and the duty cycle change of each color temperature channel, a phased duty cycle change sequence is obtained. This sequence consists of several sequentially executed adjustment stages, each stage containing at least the target duty cycle of the channel and the stage execution duration (or number of execution cycles). The sequence is used to reasonably divide the total change into several stages of the transition time, so that the duty cycle gradually transitions from the current value to the target value: First, the length matches the time, the total duration of the sequence is consistent with the transition time, and the last stage absorbs the margin; second, the synchronization rule is followed, each channel advances in any stage according to the same proportion of the synchronization step size or according to a predetermined proportion, avoiding proportional shifts caused by inconsistent channel order; third, monotonicity and boundaries are maintained, each channel maintains monotonically increasing / decreasing in the sequence, and the stage target duty cycle is limited to an effective range, if it exceeds the boundary, it is truncated and supplemented in the end segment or the next sequence; fourth, quantization and precision are matched, the stage target is quantized according to control granularity, and the margin formed by quantization error is evenly distributed or pre-allocated in subsequent stages.

[0072] This embodiment selects the color temperature channel with the largest duty cycle change as the benchmark, determines the synchronization adjustment step size of all channels based on the benchmark channel, and then further divides the total change into a phased duty cycle change sequence executed in chronological order, clarifying the target duty cycle and execution time for each stage for the two channels. The direct effect of this is that the cold and warm channels advance simultaneously at a unified pace throughout the entire transition process, and the proportional relationship between channels is constrained to near the target relationship in each stage, eliminating the phenomenon of one channel being fast at first and then slowing down while another channel lags behind.

[0073] Furthermore, this scheme no longer directly jumps to the target duty cycle. Instead, it adaptively obtains the single-step adjustment amount and transition time based on the difference between the target brightness and the threshold. In the low-brightness region, it automatically selects a smaller single-step adjustment amount and a longer transition time, while in the high-brightness region, it selects a larger single-step adjustment amount and a shorter transition time, thus setting an appropriate granularity and rhythm from the source. Subsequently, the total change is decomposed into a phased sequence using this granularity, ensuring that the increase or decrease of the duty cycle in each phase has monotonicity and boundary constraints. Quantization and margin absorption are performed according to the control granularity to avoid the step-like effect caused by quantization residuals.

[0074] In this embodiment, step S427: adjusting the current duty cycle according to the phased duty cycle change sequence during the transition time includes:

[0075] S4271: During the transition time, the current duty cycle is adjusted sequentially according to the phased duty cycle change sequence;

[0076] The transition time refers to the overall control time window allocated from the current state to the target state; the phased duty cycle change sequence is a set of target duty cycles arranged chronologically and executed segment by segment; the current duty cycle is the actual output of the controller or the quantized duty cycle before the execution of this phase. According to the phase sequence, the controller loads the target duty cycle of the channel and the phase execution duration at the beginning of each phase, and advances the duty cycle according to the synchronous step size, applying monotonicity, upper / lower limits, and quantization granularity constraints during this process. If a channel reaches the boundary or target first, the phase step size of that channel is immediately frozen, while the remaining channels continue to advance according to the phase rhythm. This ensures that the duty cycle trajectory has a continuous, monotonic, and boundary-constrained execution path, avoiding control disturbances caused by one-time jumps, and providing a reproducible phase benchmark for subsequent deviation evaluation.

[0077] S4272: After each stage, based on the deviation between the actual duty cycle and the target duty cycle of that stage, a compensation adjustment amount is obtained to correct the cumulative error and the proportional offset.

[0078] The target duty cycle for a stage refers to the channel duty cycle expected to be achieved in that stage. The actual duty cycle is the duty cycle that the controller truly activates or quantizes at the end of the stage. Deviation is the difference between the two. Cumulative error is the systematic deviation formed by the superposition of multiple stages. Proportional offset is used to characterize the deviation of the channel ratio (corresponding to color temperature ratio) from the target. At the end of each stage, the controller collects the actual duty cycle of each channel and compares it with the target duty cycle for each channel to obtain the deviation. At the same time, it calculates the difference between the channel ratio and the target ratio as the proportional offset. Then, based on preset thresholds and weights, the two types of deviations are combined into a compensation adjustment amount. Noise reduction processing, minimum effective step size, and direction constraints can be superimposed to ensure that the compensation amount can correct deviations without disrupting the predetermined monotonic progression. This allows the execution error of each stage to be immediately closed-loop into an executable compensation instruction, suppressing error accumulation and maintaining the stability of the channel ratio.

[0079] S4273: Incorporate the compensation adjustment amount into the phased duty cycle change sequence of the next stage;

[0080] Integrating refers to converting the compensation adjustment into an additional step size or target correction in the next stage sequence; the next stage sequence is the set of subsequent stage targets that have not yet been executed. Before generating the next stage sequence, the controller first reads the compensation adjustment: when the deviation is large, the compensation is preferentially allocated to the beginning of the sequence to accelerate regression; when the deviation is small, the compensation is evenly allocated to each segment to maintain smoothness; then, the stage target duty cycle and stage duration are recalculated, and boundary, quantization, and synchronization rules are applied, compressing or extending the single-segment step size as necessary to keep the total transition time unchanged. This embodiment can integrate compensation with the execution rhythm at the planning level, making the correction predictable, reproducible, and without disrupting the synchronization relationship, thereby reducing oscillations and shortening the convergence path.

[0081] S4274: When the deviation between the actual duty cycle and the corresponding target duty cycle of each color temperature channel does not exceed the preset threshold, or the number of stages executed reaches the preset maximum value, the current adjustment process is determined to have converged, and the final duty cycle parameter is output.

[0082] The preset threshold is used to determine the acceptable deviation range between the channel and the target; the maximum number of stages is used to limit the longest execution rounds; convergence refers to the state of reaching the stopping condition; the final duty cycle parameter is the stable control instruction output to the PWM signal generation module. After each stage, the controller judges the absolute deviation and proportional offset of each channel: if all do not exceed the threshold, convergence is considered; if the threshold is not reached but the stage count has reached the maximum value, the current duty cycle is fixed according to the principle of the smallest most recent error; when any condition is met, the final duty cycle parameter is locked and issued, ending the current round of adjustment, and key parameters are recorded for subsequent adaptive tuning.

[0083] In this embodiment, step S425: determining the synchronous adjustment step size for all color temperature channels based on the duty cycle change of the reference adjustment channel, combined with the single-step adjustment amount and the transition time, includes:

[0084] S4251: Determine the single-step advance amount of the reference adjustment channel based on the duty cycle change, single-step adjustment amount, and transition time.

[0085] The reference adjustment channel refers to the channel selected as the reference for adjustment rhythm among multiple color temperature channels. It is usually the channel with the largest change amplitude or the highest weight in visual perception, such as the warm white channel or cool white channel. The duty cycle change refers to the difference between the target duty cycle and the current duty cycle, reflecting the adjustment range required for that channel. The single-step adjustment amount is the minimum duty cycle increment that can be changed within one PWM control cycle or logic control step. In practice, the duty cycle change amount can be divided by the total number of steps within the transition time to obtain the theoretical advance amount per step, which is then rounded or quantized according to the granularity limit of the single-step adjustment amount. This method ensures that the change rhythm of the reference channel is consistent with the preset time, avoiding abrupt changes caused by excessively rapid changes while ensuring that adjustment delays are not caused by excessively small step sizes.

[0086] S4252: Using the single-step advance amount of the reference adjustment channel as the reference amount, determine the synchronization adjustment step size of the remaining color temperature channels according to the target ratio relationship or preset synchronization rules.

[0087] The target proportional relationship refers to the proportional relationship of brightness or color temperature changes between different channels, usually derived from target light and color coordinate calculations or color temperature mixing formulas. Preset synchronization rules may include strategies such as proportional advancement, weighted advancement, or priority for specific color gamuts. The system uses the single-step advancement amount of the reference channel as a reference, calculates the advancement amount of other channels according to a proportional coefficient, and makes corrections based on the resolution, quantization rules, and limiting conditions of each channel. This ensures that the adjustment direction and magnitude of each channel are coordinated at each step, thereby maintaining overall light and color consistency during the transition process.

[0088] S4253: Control each color temperature channel to advance brightness or color temperature changes at each stage with a consistent rhythm according to the synchronous adjustment step size described above.

[0089] Consistent timing refers to multiple channels synchronously executing adjustment actions in each control cycle, ensuring the synchronicity of the change process. In practice, a unified timer interrupt can be set within the PWM modulation controller or digital driver chip. Within the interrupt callback, the duty cycle registers of each channel are updated simultaneously, with the updated value equal to the current duty cycle plus the corresponding channel's synchronous adjustment step size. In this way, all channels complete one adjustment step at the same time, resulting in a visually smooth and coordinated transition effect.

[0090] S4254: Detects the current status of each color temperature channel. When any channel reaches the target value or the allowable boundary value first, the adjustment step size of that channel is set to zero.

[0091] Boundary values ​​refer to the maximum or minimum duty cycle allowed by the system, such as 0% and 100%, used to prevent exceeding these limits. After each stage, the system reads the current duty cycle of each channel and compares it with the target duty cycle. If the difference is within the threshold range or has reached the boundary value, the adjustment step size of that channel is set to 0, while the step size of other channels is maintained. This avoids unnecessary calculations and control actions while ensuring safety and color accuracy, thus improving system stability and response efficiency.

[0092] In this embodiment, step 426: Based on the synchronous adjustment step size and the duty cycle change of each color temperature channel, a phased duty cycle change sequence is obtained. The phased duty cycle change sequence includes several adjustment stages executed sequentially. Each adjustment stage includes at least the target duty cycle of the channel in that stage and the stage execution duration, including:

[0093] S4261: Based on the synchronous adjustment step size and the duty cycle change of each color temperature channel, determine the total change required for each color temperature channel to transition from the current duty cycle to the target duty cycle;

[0094] The synchronization adjustment step size refers to the smallest increment or decrement unit used to synchronously advance the duty cycle changes of multiple color temperature channels within the same time frame, such as a duty cycle of 0.5% or 1%. The total change represents the overall difference required for a color temperature channel to transition from its current duty cycle value to its target duty cycle value. In practice, the system first reads the difference between the current duty cycle and the target duty cycle, combines it with the previously determined synchronization adjustment step size, calculates the total number of steps or the total change amplitude required for each channel, and stores the results in the adjustment parameter table. This ensures that the adjustment range and stepping rhythm of each channel are based on precise quantitative calculations, avoiding channel inconsistencies caused by inaccurate estimations.

[0095] S4262: Divide the total change into several sequentially executed adjustment phases within a preset transition time to obtain a phased duty cycle change sequence, wherein each adjustment phase includes at least the channel target duty cycle and the phase execution duration or number of execution cycles for that phase.

[0096] The preset transition time refers to the total execution duration allocated by the system for the current adjustment process, such as 2 seconds or 1 minute. The phased duty cycle change sequence divides the total change into multiple phases, each with its own target duty cycle and execution duration. The purpose of this step is to make the adjustment process smoother and more controllable through a segmented approach, while also providing intervention points for real-time detection and error correction. In implementation, the control module divides the entire process into several consecutive phases based on the total change and transition time, combined with the expected number of execution cycles for each phase, and assigns a target duty cycle and duration to each phase. This segmented processing allows the system to perform state detection and strategy adjustment during phase transitions, avoiding sudden brightness changes caused by large, one-time changes. This improves visual smoothness and the naturalness of color temperature transitions.

[0097] S4263: In the phased duty cycle change sequence, each color temperature channel is controlled to advance in any phase according to the same proportion of the synchronous adjustment step size or a preset proportion.

[0098] Proportional advancement means that each channel advances in a consistent manner according to the same adjustment step size ratio within the same stage; preset ratio allows for differentiated advancement based on spectral distribution, color rendering requirements, or other predefined strategies. The purpose of this step is to maintain a stable brightness and color temperature relationship across multiple channels during phased adjustments, preventing overall color shift due to a channel advancing too quickly or too slowly. When executing a certain stage, the controller multiplies the advancement step size of the reference channel by the corresponding proportional coefficient and applies it to each channel, ensuring that the adjustment range of different channels in that stage conforms to the set proportional rules. This ensures consistent optical output across color temperature channels, making it particularly suitable for multi-channel LED systems in scenarios requiring high color mixing accuracy.

[0099] S4264: Constrain the duty cycle of each color temperature channel to either increase or decrease monotonically within each stage.

[0100] When generating the phased change sequence, the system sets a direction flag for each channel, for example, only allowing the duty cycle to increase or decrease in that phase. If real-time detection detects a trend reversal, the update of that channel is temporarily suspended until the next phase. This ensures the predictability of changes in each phase and the stability of the output. Its beneficial effects include reducing the risk of brightness flicker or color temperature jumps and improving the smoothness of the control process.

[0101] S4265: Quantize the target duty cycle of each stage according to the control granularity, and evenly distribute the surplus formed by the quantization error to the subsequent stages or distribute it to the previous stage in advance.

[0102] Control granularity refers to the smallest unit of duty cycle change that the system can precisely control when outputting a PWM signal, such as 0.1% or 0.5%. Quantization error is the deviation that occurs when rounding the target duty cycle to the control granularity. The purpose of this step is to prevent significant shifts in color temperature or brightness by evenly distributing the quantization error. When the target duty cycle at a certain stage has a margin after quantization, this margin is recorded and allocated to subsequent stages according to the strategy, or allocated in advance in the early stages, to ensure that the total error at final convergence is zero. This embodiment improves the accuracy and consistency of adjustment, especially in high-precision dimming or color temperature control, and can effectively eliminate color shift and brightness errors caused by PWM resolution limitations.

[0103] S4266: During execution, the phased duty cycle change sequence is updated based on real-time detection results or external instructions.

[0104] The real-time detection results include current, voltage, and brightness sensor data, as well as ambient light parameters. External commands can come from user operation, host computer control, or automated scene systems. The purpose of this step is to retain dynamic intervention capability during the adjustment process, enabling the system to adjust its strategy in real time according to unexpected situations or optimization needs. In implementation, the control module detects sensor feedback and control commands within each stage execution cycle. When a change in the target is detected (such as external scene switching, manual user adjustment, excessively high temperature, etc.), the phased change sequence is recalculated and the subsequent execution plan is replaced. This embodiment can improve the system's flexibility and adaptability, ensuring that color temperature and brightness adjustments not only meet the preset transition effect but also respond promptly to external changes, thereby improving the overall level of intelligence.

[0105] This embodiment provides the following two modes to switch the target brightness based on the detection results of human activity:

[0106] When the first mode is used, step S6: adjusting the target brightness to a first brightness when human activity is detected includes adjusting the output level signal of the control current to a high level signal. Step S7: adjusting the target brightness to a second brightness if no human activity is detected again within the first duration after the initial detection includes adjusting the output level signal of the control current to a low level signal. In this step, when the microcontroller receives a human movement signal from the microwave sensor, it switches the output level of the control circuit from low to high, causing the drive current to quickly reach the preset first brightness. If no human movement signal is received again before the end of the first duration, the microcontroller switches the output level back to low, causing the drive current to decrease to the preset second brightness.

[0107] In this embodiment, updating the phased duty cycle change sequence based on real-time detection results or external instructions during execution includes:

[0108] The current control mode is determined based on real-time detection results and external commands;

[0109] This step combines results such as whether someone is present or not, activity intensity, and distance to the downlights with user commands, and maps them to control modes such as fast response, comfortable transition, nighttime micro-motion retention, and energy saving according to priority, serving as a guide for subsequent parameter updates.

[0110] Based on the current control mode, a target transition time is set to obtain a new transition time; the transition time is shortened for rapid response, extended for comfortable transition and nighttime micro-motion, and extended for energy saving; the transition time directly constrains the subsequent stage segmentation and step size upper limit.

[0111] Based on the intensity and distance of human activity, step length weight is determined to obtain step length weight level;

[0112] In practice, high-activity or short-distance activities are given a larger step size weight; low-activity activities are given a medium weight; minor movements or long-distance activities are given a smaller weight; and when no one is around, the weight is slightly smaller to facilitate energy saving and smoothing.

[0113] Based on the step size weight level and the new transition time, a new synchronization step size is set to obtain the synchronization adjustment step size. Within the time constraint, the executable single-step advancement amount is calculated; the larger the weight and the shorter the time, the larger the step size; ensuring that each color temperature channel still advances according to the synchronization or preset ratio.

[0114] Based on the target brightness and color temperature from external instructions, an unconstrained sequence of stage targets is obtained; the final target is decomposed into the channel target duty cycle of each stage, forming a basic list to provide input for subsequent clipping and error processing.

[0115] Based on the preset perception threshold and monotonic change constraint, single-step amplitude constraint is applied to obtain a constrained stage target sequence.

[0116] If a single step change in a certain stage exceeds the threshold acceptable to the human eye, it will automatically be subdivided into more small steps or the pace will be slowed down; at the same time, it will maintain the monotony of only increasing or only decreasing to avoid visual jumps and flickering.

[0117] Based on the current cumulative error and the new transition time, a time compression determination is made to obtain a time compression flag. When the error is large and the time is insufficient for natural digestion, the flag is set to open a channel for accelerated convergence when necessary. If it can be digested naturally, no compression is performed.

[0118] Based on the time compression flag and step size weight level, the stage beat is adjusted to obtain the compressed stage number and stage duration table; when set, the number of stages is reduced or the duration of each stage is shortened, and the single step advance is appropriately amplified; when not set, the original beat is maintained; monotonicity and anti-flicker constraints are always observed.

[0119] Based on the control granularity, the target sequence is quantized to obtain the quantized stage target and quantization error margin; the stage target is aligned to the discrete level of the control granularity to generate an executable target; the quantization difference is used as the margin for the next allocation step.

[0120] Based on human activity and step length weight levels, the direction of residual allocation is determined to obtain the allocation direction;

[0121] When there is high activity or close proximity, the first segment is prioritized to approach the target more quickly; when there is low activity or no one is around, the second segment is spread out or subdivided throughout to smooth energy saving; when there is slight movement at night, subdivision is prioritized to reduce disturbance.

[0122] Based on the allocation direction and the execution duration of each stage, the remaining capacity is allocated to obtain the corrected stage target sequence;

[0123] Distribute surplus capacity to stages that are less noticeable or require faster acceleration; prioritize stages with longer execution times or lower visual sensitivity to allocate surplus capacity; ensure that the advancement rhythm of multiple channels is consistent or follows a preset ratio in the same stage.

[0124] Based on the current execution progress and the PWM cycle boundary, a seamless switch is performed to obtain the new sequence's enabled status.

[0125] The transition is made at either the stage boundary or the full cycle boundary. If the starting point of the new sequence differs significantly from the current state, a very short buffer stage is inserted before switching to ensure a continuous and stable visual experience.

[0126] S6: Adjusting the target brightness to a first brightness when human activity is detected includes adjusting the duty cycle of the pulse width modulation (PWM) signal of the control current to a first duty cycle. S7: If no further human activity is detected within a first duration after the initial detection, adjusting the target brightness to a second brightness includes adjusting the duty cycle of the PWM signal of the control current to a second duty cycle. When human activity is detected, the target brightness is adjusted to the first brightness by adjusting the duty cycle of the PWM signal of the control current to the first duty cycle. If no further human activity is detected within the first duration, the target brightness is adjusted to the second brightness, and the duty cycle of the PWM signal is adjusted accordingly to the second duty cycle. This ensures that the system dynamically adjusts the brightness based on human movement.

[0127] In this embodiment, the quantization processing of the target duty cycle at each stage according to the control granularity, and the uniform distribution of the surplus formed by the quantization error to subsequent stages or the advance distribution to the earlier stages, further includes:

[0128] The margin is weighted and allocated based on the execution time of each stage, the range of human visual sensitivity, and the priority of the color temperature channel.

[0129] Margin refers to the total duty cycle error caused by rounding after quantization; execution time is the estimated running time for this stage; visual sensitivity range is the range in which the human eye is more sensitive to changes in color temperature / brightness. Channel priority is a level classified according to the impact of different color temperature channels on overall light effect and color reproduction.

[0130] After quantification, the duration of each stage, whether it falls within the human eye's sensitive range, and the importance of each channel are calculated. Different weights are then assigned to these factors. Error margins are allocated based on these weights; for example, stages with longer execution times receive more weight, while high-priority channels receive less. This results in a differentiated allocation scheme, rather than a simple average distribution. In this way, users can barely perceive abrupt changes in brightness or color temperature, improving visual comfort, while errors are absorbed more effectively, preventing concentrated spikes later on.

[0131] The actual duty cycle of each color temperature channel is collected and compared with the target duty cycle to obtain the single-stage error of each channel and accumulate them to form the cumulative error;

[0132] Single-stage error refers to the difference between the actual output duty cycle and the target duty cycle at the end of a certain stage; cumulative error is the overall deviation formed by gradually accumulating the errors of multiple stages.

[0133] At the end of each stage, the system reads the actual duty cycle of each channel, which can be obtained through the driver chip register or current detection circuit. This data is then compared with the target value to calculate the difference for each channel. These differences are then gradually accumulated to obtain the total error. If the error remains small, the original sequence continues to execute; if it accumulates, it provides a basis for triggering subsequent reallocation. This embodiment can identify potential offset risks early on, avoiding noticeable color temperature or brightness changes in the final stage.

[0134] When the cumulative error exceeds the error threshold, the total change for the remaining stages is recalculated.

[0135] Error threshold refers to the pre-set allowable error range of the system. There are usually two levels: a small threshold for normal compensation and a large threshold requiring global recalculation. The system determines whether the cumulative error exceeds the preset large threshold; if so, it immediately enters the redistribution mode. In this mode, it first calculates the total amount of adjustment still needed for each channel, as well as the remaining transition time, and then, combined with the user-defined response mode (fast mode or comfortable mode), decides whether to shorten the number of stages, increase the adjustment magnitude, or change the adjustment rhythm.

[0136] Based on the remaining transition time and the magnitude of the cumulative error, the target duty cycle and corresponding adjustment step size of each color temperature channel are dynamically adjusted to generate a new phased duty cycle change sequence.

[0137] Replanning sequence refers to generating a completely new set of stage adjustment steps based on new calculation results to replace the original plan. The system first calculates how much difference is needed for each channel to reach the target state from the current state, and then decomposes these differences into new adjustment steps based on the remaining time. If the remaining time is tight, the adjustment step size is increased or the duration of each stage is shortened; if time is relatively ample, the number of stages can be increased to break down the adjustment process into finer steps and make the transition smoother. All of these are recombined into a new staged table and activated at the start of the next stage, thus ensuring that even with large errors, the transition can be completed within a range that is imperceptible or only slightly noticeable to the user.

[0138] In the new phased duty cycle change sequence, the cumulative error is allocated by means of compensation based on the proportion of the remaining change, priority channel compensation, or dynamic time compression.

[0139] Error allocation strategies refer to how to distribute accumulated errors across different channels and stages during the replanning process. Common methods include: allocating according to the proportion of remaining adjustment, prioritizing compensation for certain critical channels, or forcing convergence through time compression. If the error in a particular channel is found to be significantly dominant, more correction can be allocated to that channel; if the error distribution across all channels is relatively uniform, allocation can be based on the proportion of remaining change; if the system detects insufficient remaining time, time compression can be used to accelerate the adjustment speed without causing flicker. Specifically, this includes:

[0140] When the cumulative error exceeds the preset threshold and the remaining transition time is insufficient to complete the original sequence adjustment, dynamic time compression is triggered.

[0141] Obtain the remaining duty cycle difference and remaining transition time for each color temperature channel;

[0142] Reduce the number of remaining stages in the original sequence and shorten the execution time of each stage;

[0143] The single-step adjustment range of each stage is increased accordingly, so that each color temperature channel can reach the target duty cycle within the compressed stage;

[0144] During execution, the direction of single-step adjustment is constrained to be monotonically increasing or monotonically decreasing, and the magnitude of single-step adjustment is limited to not exceeding a preset perception threshold.

[0145] During execution, the direction of single-step adjustment is constrained to be monotonically increasing or monotonically decreasing, and the magnitude of single-step adjustment is limited to not exceeding a preset perception threshold.

[0146] The preset perception threshold refers to the minimum range of change that a user's naked eye can perceive during the adjustment of lighting brightness or color temperature. Adjustments below this threshold are usually not noticeably perceived by the human eye, while adjustments exceeding this threshold may cause abrupt changes or flickering.

[0147] By introducing a dynamic time compression mechanism into the phased duty cycle change sequence, when the accumulated error is too large and the remaining transition time is insufficient, the execution time of subsequent stages can be proactively shortened and the single-step adjustment amplitude increased, enabling each color temperature channel to quickly converge to the target value within a limited time. This approach avoids the problem of insufficient transition time leading to incomplete adjustment in traditional solutions, ensuring the accuracy of the final output of brightness and color temperature. Simultaneously, by constraining the monotonicity of the single-step adjustment direction and limiting the perception threshold of the single-step amplitude, abrupt changes in luminous efficacy and visually perceptible flickering are avoided. This ensures both rapid response and visual comfort, significantly improving the system's stability and user experience in complex application scenarios.

[0148] The original sequence is overwritten with the new phased duty cycle change sequence and enabled during the next phase of execution.

[0149] During the switching process, the system selects an appropriate time point, such as the end of a PWM cycle, to avoid mid-process abrupt changes. It also checks if the starting point of the old and new sequences differs significantly from the current actual value; if so, a transition phase is inserted for buffering. Furthermore, the system retains a backup of the original sequence to allow for rollback in case of switching failure. This embodiment, by introducing quantization error weighting, staged error detection, cumulative error judgment, and global replanning mechanisms during the phased duty cycle adjustment process, achieves closed-loop control from local compensation to global optimization. This not only ensures the smoothness and eye comfort of multi-color temperature downlights during brightness and color temperature transitions but also allows for timely correction when errors accumulate or the environment changes, ensuring accurate convergence of the final adjustment result.

[0150] Example 2

[0151] This embodiment provides a multi-color temperature downlight, including a first LED bead, a second LED bead, and a control circuit. The first LED bead and the second LED bead have different color temperatures. The control circuit is electrically connected to the first LED bead and the second LED bead respectively. The control circuit stores computer program instructions, and when the computer program instructions are executed by the processor, the method described in the first aspect is implemented.

[0152] The control circuit includes a filter sub-circuit, a signal amplification sub-circuit, and a microcontroller. The filter sub-circuit is electrically connected to the microwave sensor, the signal amplification sub-circuit is electrically connected to the filter sub-circuit, the microcontroller is electrically connected to the signal amplification sub-circuit, and the microcontroller is electrically connected to the first LED bead and the second LED bead respectively.

[0153] This embodiment uses LED beads with different color temperatures for color temperature control. The control circuit can control the brightness ratio of LED beads with different color temperatures so that the color temperature of the downlight meets the user's needs.

[0154] like Figure 6 As shown, the multi-color temperature downlight in this embodiment also includes a microwave induction control module, which is electrically connected to the control circuit. This embodiment integrates a microwave sensor on top of the existing multi-color temperature LED and control circuit. This sensor is connected to the control circuit via an electrical interface and can detect human activity in the environment in real time and transmit signals to the controller to trigger automatic dimming or switching on / off functions. Because microwave induction technology not only has a long sensing distance, large angle, and strong anti-interference capability, but is also unaffected by light, it can achieve more precise and stable intelligent induction control.

[0155] In this embodiment, the microwave sensor is integrated into the lamp panel of the multi-color temperature downlight, and its antenna layout has been optimized to ensure sensing range and sensitivity.

[0156] The control circuit for the downlight with microwave induction function for color temperature adjustment in this embodiment also includes a power drive circuit, a dimming and color temperature adjustment control circuit, and a microwave induction control module. The power drive circuit adopts a flyback switching power supply architecture, obtains energy from the AC mains input terminal, and provides a stable low-voltage DC power supply for the dimming and color temperature adjustment control circuit and the microwave induction control module.

[0157] The power drive circuit includes:

[0158] AC input and surge suppression unit;

[0159] The L terminal of the AC input terminal CON1 of the AC input and surge suppression unit is connected to one end of the current-limiting resistor R5, and the other end of R5 is connected to one of the AC input terminals of the rectifier bridge BR1 (MB6S); the N terminal of CON1 is directly connected to the other AC input terminal of BR1. The two ends of the varistor ER1 are connected in parallel across the two ends of R5 to absorb and protect against mains overvoltage.

[0160] Rectifier and filter unit;

[0161] The positive DC output terminal of the rectifier filter unit BR1 is connected to one end of the high-voltage filter capacitor C2 and one end of the inductor L1; the negative DC output terminal of BR1 serves as the power ground and is connected to the other end of C2. The other end of L1 is connected to one end of capacitor C3, and the other end of C3 is grounded; the filter branch formed by L1 and C3 in parallel is output to the switching power supply control unit.

[0162] Switching power supply control unit;

[0163] The high-voltage input pin of the high-voltage flyback switching power supply control chip U1 (BP3525XX) in the switching power supply control unit is connected to the node of L1 and C3. One end of its startup capacitor C1 is connected to the startup pin of U1, and the other end is grounded. The sensing resistor R1 is connected in series in the switching circuit of U1 to sample the current signal. The output pin of U1 is connected to one end of the primary winding of the transformer, and the other end of the primary winding returns to the high-voltage DC positive terminal, thus forming the energy conversion circuit of the flyback power supply.

[0164] Secondary rectification and output filtering unit;

[0165] In the secondary rectification and output filtering unit, one end of the transformer's secondary winding is connected to the anode of the high-frequency rectifier diode D2 (ES1J), and the cathode of D2 is connected to one end of the inductor L2. The other end of L2 serves as the output positive terminal and is connected to one end of the filter capacitor C5, with the other end of C5 grounded. The cathode of diode D3 (ES1J) is connected to the output terminal of L2, while its anode is grounded to prevent reverse current surges. The output positive terminal is also connected to a filter capacitor C4, with the other end of C4 grounded to further smooth the output voltage.

[0166] Output terminal;

[0167] The output terminal VOUT has its V terminal connected to the output terminal of L2, its G terminal connected to the power ground, and its O terminal as the signal interface terminal, connected to the signal input terminal of the control circuit. This low-voltage DC positive terminal is simultaneously connected to the power input terminals of both the dimming and color temperature control circuit and the microwave induction control module, while the negative terminal shares a common ground.

[0168] In this embodiment, the dimming and color temperature control circuit includes a PWM dimming unit and a dual-color temperature LED driving unit. The PWM dimming unit outputs two PWM signals from a microcontroller (MCU), which are respectively connected to the control terminals of the cool white LED driving branch and the warm white LED driving branch. By adjusting the PWM duty cycle, the driving current ratio of the two types of LEDs is changed, achieving continuous adjustment of the color temperature between approximately 2700K and 6500K, while simultaneously controlling the overall brightness. The control terminals of the cool white LED driving branch and the warm white LED driving branch are electrically connected to the first LED and the second LED, respectively.

[0169] The power input terminal of the microwave sensing control module is connected to the output terminal VOUT, and the signal output terminal is connected to the sensing input pin of the MCU. The microwave sensing module adopts a 5.8GHz transmit-receive structure. When human activity is detected, it outputs a high-level signal to drive the MCU to control the PWM output, thereby lighting up the LED. After a preset time of no human presence, the MCU stops the PWM output and turns off the LED, realizing automated energy-saving control.

[0170] The above is a detailed description of the pulse width modulation intelligent control method for multi-color temperature downlights provided in the embodiments of the present invention.

[0171] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0172] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the required tasks. The programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0173] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0174] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights, characterized in that, The method includes the following steps: The target brightness of the downlight is obtained, wherein the downlight has multiple LED beads, and the target brightness of the downlight is the overall brightness of the downlight; Obtain the user's color temperature requirements; The target brightness of each LED bead in the downlight is determined based on the target brightness and the color temperature requirement, wherein at least two LED beads have different color temperatures; Control each LED bead to emit light at the target brightness; In obtaining the target brightness of the downlight, the user can obtain the overall brightness required by the user through the brightness adjustment switch, the user operation interface, or the preset scene mode; The step of determining the pulse width adjustment duty cycle for each LED based on the target current for each LED also includes: Obtain the target current of the LED beads to get the target duty cycle of each color temperature channel; Based on the difference between the target duty cycle and the current duty cycle, the amount of duty cycle change that each channel needs to adjust is obtained; The color temperature channel with the largest duty cycle change is selected as the baseline adjustment channel; Based on the difference between the current target brightness and the preset brightness threshold, the single-step adjustment amount and transition time of the reference adjustment channel are obtained; Based on the duty cycle change of the baseline adjustment channel, combined with the single-step adjustment amount and transition time, the synchronous adjustment step size of all the color temperature channels is determined. Based on the synchronous adjustment step size and the duty cycle change of each color temperature channel, a phased duty cycle change sequence is obtained. The phased duty cycle change sequence includes several adjustment stages executed sequentially. Each adjustment stage includes at least the target duty cycle of the channel in that stage and the stage execution time. During the transition period, the current duty cycle is adjusted according to the phased duty cycle change sequence; The step of determining the synchronous adjustment step size for all color temperature channels, based on the duty cycle change of the reference adjustment channel and combined with the single-step adjustment amount and transition time, includes: The single-step advance amount of the reference adjustment channel is determined based on the change in duty cycle of the reference adjustment channel, the single-step adjustment amount, and the transition time. Using the single-step advance amount of the aforementioned reference adjustment channel as the reference amount, the synchronization adjustment step size of the remaining color temperature channels is determined according to the target proportional relationship or preset synchronization rules. Control each color temperature channel to advance brightness or color temperature changes at each stage in a consistent rhythm according to the synchronous adjustment step size described above. The current status of each color temperature channel is detected. When any channel reaches the target value or the allowable boundary value first, the adjustment step size of that channel is set to zero. The method further includes: The microwave sensor detects whether there is human movement in the target area. The microwave sensor periodically emits high-frequency electromagnetic waves at a preset transmission power and receives the reflected echo signal. When human movement is detected, adjust the target brightness to the highest level. If no further human movement is detected within the first duration after human movement is detected, the target brightness will be adjusted to the second brightness. If no human movement is detected again during the second duration after the target brightness is adjusted to the second brightness, the downlight will be turned off.

2. The pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights according to claim 1, characterized in that, The step of adjusting the target brightness to the first brightness when human movement is detected includes adjusting the output level signal of the control current to a high level signal. The step of adjusting the target brightness to the second brightness if no human movement is detected again within the first duration after human movement is detected includes adjusting the output level signal of the control current to a low level signal.

3. The pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights according to claim 1, characterized in that, The step of adjusting the target brightness to a first brightness when human movement is detected includes adjusting the duty cycle of the pulse width modulation signal of the control current to a first duty cycle. The step of adjusting the target brightness to a second brightness if no human movement is detected again within a first duration after human movement is detected includes adjusting the duty cycle of the pulse width modulation signal of the control current to a second duty cycle.

4. The pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights according to claim 1, characterized in that, The method of controlling each LED to emit light at a target brightness also includes: Determine the target current for each LED bead based on its target brightness. The pulse width modulation duty cycle of each LED is determined based on the target current of each LED. The output current of the circuit is controlled by the pulse width modulation signal output according to the pulse width modulation duty cycle.

5. The pulse width modulation intelligent control method for microwave detection of multi-color temperature downlights according to claim 1, characterized in that, The step of adjusting the current duty cycle during the transition time according to the phased duty cycle change sequence further includes: During the transition period, the current duty cycle is adjusted sequentially according to the phased duty cycle change sequence; After each stage, the compensation adjustment amount used to correct the cumulative error and proportional offset is obtained based on the deviation between the actual duty cycle and the target duty cycle of that stage. The compensation adjustment amount is incorporated into the phased duty cycle change sequence of the next stage; When the deviation between the actual duty cycle and the corresponding target duty cycle of each color temperature channel does not exceed the preset threshold, or when the number of stages executed reaches the preset maximum value, the current adjustment process is determined to have converged, and the final duty cycle parameter is output.

6. A microwave detection system for multi-color temperature downlights, characterized in that, The device includes a first LED, a second LED, a control circuit, and a microwave sensor. The first and second LEDs have different color temperatures. The control circuit is electrically connected to both the first and second LEDs. The microwave sensor is electrically connected to the control circuit. The control circuit stores computer program instructions, which, when executed by a processor, implement the method as described in any one of claims 1-5.

7. The microwave detection multicolor temperature downlight according to claim 6, characterized in that, The control circuit includes a power drive circuit, which includes an AC input and surge suppression unit. The L terminal of the AC input terminal CON1 of the AC input and surge suppression unit is connected to one end of the current limiting resistor R5, and the other end of R5 is connected to one of the AC input terminals of the rectifier bridge BR1. The N terminal of CON1 is directly connected to the other AC input terminal of BR1. The two ends of the varistor ER1 are connected in parallel to the two ends of R5. The power drive circuit also includes a rectification and filtering unit. The positive DC output terminal of the rectification and filtering unit is connected to one end of the high-voltage filter capacitor C2 and one end of the inductor L1. The negative DC output terminal of the rectification and filtering unit serves as the power ground and is connected to the other end of C2. The other end of the inductor L1 is connected to one end of the capacitor C3, and the other end of C3 is grounded. The filter branch formed by the parallel connection of inductor L1 and capacitor C3 is output to the switching power supply control unit.

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