LED driving power supply and output control method thereof

Abstract

The application discloses an LED driving power supply and an output control method thereof. The method comprises the following steps: collecting an output current signal of an LED lamp in real time, and obtaining a ripple component time domain signal of the current through high-frequency sampling; performing narrowband FFT analysis on the ripple component time domain signal, and calculating the energy proportion of the ripple component time domain signal in a preset frequency band; generating a reference current based on a target brightness, calculating a double-channel dynamic compensation current according to the reference current, the ripple component time domain signal and the energy proportion in the preset frequency band; superimposing the double-channel dynamic compensation current to a driving signal to generate a ripple suppression current, performing smoothing processing on the ripple suppression current through multi-stage adaptive filtering, and driving the LED lamp according to the processed current signal. The application realizes high precision, high stability, low ripple, fast response and smooth output of the LED driving current, and improves the visual quality and reliability of the LED lighting product.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of LED control, in particular to an LED driving power supply and an output control method thereof. BACKGROUND

[0002] LED lighting has been widely used in various fields due to its advantages of high efficiency, long service life and environmental protection. However, the brightness of the LED is highly dependent on the accuracy and stability of the driving current. In the traditional LED driving power supply, especially in the scheme of using a switching power supply or PWM dimming, the output current inevitably contains ripples. These ripples mainly come from the power supply switching action, input voltage fluctuation, load change and circuit parasitic parameters.

[0003] The prior art usually faces the following key problems when dealing with LED driving current ripples and realizing precise constant current control: first, the traditional method often only relies on low-frequency sampling or simple average filtering to obtain current feedback, which is difficult to effectively separate and quantify the ripple components and their energy distribution in a specific frequency band, so as to accurately locate and specifically suppress the harmful ripples that have the greatest impact on visual perception (such as the human eye sensitive frequency band) or the most significant impact on LED performance. Second, the prior art mainly focuses on static or slow-changing average current error compensation, such as simple PI control, and has limited real-time and active suppression capability for dynamic ripples. The compensation based on error integration or proportional regulation has inherent response delay, which is difficult to cope with rapid changes in load or input disturbance, and is easy to cause instantaneous brightness fluctuation or flicker. Third, the fixed parameter low-pass filter introduced to suppress ripples, although it can smooth the current, will significantly reduce the system bandwidth and dynamic response speed. In the case of dimming or load mutation, it is easy to cause slow LED current establishment / shut-off, brightness tracking delay, and even overshoot / undershoot, resulting in poor current stability and ripple suppression effect under dimming. SUMMARY

[0004] In order to solve at least one of the above technical problems, the application provides an LED driving power supply and an output control method thereof.

[0005] In a first aspect, the application provides an output control method of an LED driving power supply, the method comprising:

[0006] Real-time acquisition of the output current signal of the LED lamp, high-frequency sampling to obtain the ripple component time domain signal of the current;

[0007] Performing narrowband FFT analysis on the ripple component time domain signal to calculate the energy proportion of the ripple component time domain signal in the preset frequency band;

[0008] The reference current is generated based on the target brightness, and a double-channel dynamic compensation current is calculated according to the reference current, the ripple component time domain signal, and the energy proportion in the preset frequency band.

[0009] The double-channel dynamic compensation current is superimposed on the driving signal to generate a ripple suppression current, the ripple suppression current is smoothed through multi-stage adaptive filtering, and the LED lamp is driven according to the processed current signal.

[0010] Preferably, the reference current is generated based on the target brightness, and a double-channel dynamic compensation current is calculated according to the reference current, the ripple component time domain signal, and the energy proportion in the preset frequency band.

[0011] The ripple amplitude compensation of the first channel is calculated as follows:

[0012] ;

[0013] In the formula, is the ripple amplitude compensation, is the ripple compensation gain coefficient, , is the current PWM duty cycle; is the ripple component time domain signal; is the energy proportion of the ripple component time domain signal in the preset frequency band, which is calculated by the ratio of the preset frequency band ripple energy to the full frequency band ripple energy, and the value range is [0, 1]; is the reference current, is the actual output current; represents the compensation direction, and satisfies:

[0014] ;

[0015] The trend leading compensation of the second channel is calculated as follows:

[0016] ;

[0017] In the formula, is the trend leading compensation, is the trend compensation gain coefficient, and the value range is [0.8, 1.2], is the hyperbolic tangent function, is the absolute error of the reference current and the actual output current, is the nonlinear regulation threshold, is the differential compensation weight coefficient, and , is the differential term of the error;

[0018] The double-channel dynamic compensation current is determined as follows:

[0019] ;

[0020] wherein, is a double-channel dynamic compensation current.

[0021] Preferably, the method further comprises adaptively adjusting the trend compensation gain coefficient:

[0022] ;

[0023] wherein, is a trend compensation gain coefficient, is a calibration parameter, is a current PWM duty cycle, is a natural constant.

[0024] Preferably, the method further comprises:

[0025] determining whether the current PWM duty cycle is less than a first preset value, and if the current PWM duty cycle is less than the first preset value, performing dynamic adjustment of the constant current circuit, comprising:

[0026] calculating a real-time current saturation critical value, and if the ratio of the peak value of the actual output current to the current saturation critical value exceeds a second preset value, triggering a triple protection mechanism; the triple protection mechanism comprises increasing the switching frequency, injecting a high-frequency jitter signal to disperse electromagnetic energy, and dynamically limiting the current.

[0027] Preferably, the preset frequency band is a human eye visual sensitivity frequency band, and the value range is dynamically optimized through a visual model, comprising:

[0028] dividing different human eye visual sensitivity frequency bands according to environmental brightness;

[0029] constructing a stroboscopic sensitivity function, and updating the divided human eye visual sensitivity frequency band according to the size of the stroboscopic sensitivity; wherein the stroboscopic sensitivity function is as follows:

[0030] ;

[0031] wherein, is a stroboscopic sensitivity, is a most sensitive frequency, and the default is 100 Hz, is a bandwidth factor, is a frequency, is a maximum sensitivity of the human eye.

[0032] Preferably, the method further comprises:

[0033] When it is detected that the current duty cycle is lower than a third preset value and the duration exceeds a preset length of time, switching to a hybrid dimming mode, and activating a retinal protection algorithm to limit the current ripple peak-to-peak value within a preset range; in the hybrid dimming mode, the PWM duty cycle is fixed at 0.25, and the brightness is supplemented by analog dimming.

[0034] Preferably, the smoothing of the ripple suppression current by the multi-stage adaptive filter comprises:

[0035] According to the current dimming duty cycle The filter cutoff frequency is selected as:

[0036] ;

[0037] In the formula, is the filter cutoff frequency, is the attenuation coefficient, and , The current is the PWM duty cycle, is a natural constant; , The minimum cutoff frequency and the maximum cutoff frequency are respectively;

[0038] The switchable capacitor array is used to dynamically adjust the LC filter parameters to match the cutoff frequency.

[0039] Preferably, the switchable capacitor array includes a first capacitor, a second capacitor, and a third capacitor;

[0040] The ratio of the second capacitor to the first capacitor is equal to the ratio of the third capacitor to the second capacitor.

[0041] When the filter cutoff frequency is greater than 10KHz, the first capacitor is enabled;

[0042] When the filter cutoff frequency is greater than 1KHz and less than or equal to 10KHz, the first capacitor and the second capacitor are enabled;

[0043] When the filter cutoff frequency is less than or equal to 1KHz, the first capacitor, the second capacitor, and the third capacitor are enabled.

[0044] In a second aspect, the application also provides an LED driving power supply suitable for the output control method of the LED driving power supply according to any one of the first aspect, comprising:

[0045] A high-frequency sampling module is configured to obtain a ripple component time-domain signal of the current by high-frequency sampling;

[0046] A dynamic compensation engine is configured to calculate a double-channel dynamic compensation current according to the ripple component time-domain signal.

[0047] A control chip is configured to superimpose the dual-channel dynamic compensation current on the driving signal to generate a ripple suppression current.

[0048] An adaptive filter bank including a magnetic bead filter and a switchable capacitor array is configured to smooth the ripple suppression current by multi-stage adaptive filtering to drive the LED lamp.

[0049] Compared with the prior art, the application has the following beneficial effects:

[0050] 1) The application acquires the current ripple component time domain signal by high-frequency sampling, and calculates the energy proportion in the preset key frequency band, such as the human eye sensitive frequency band or the vicinity of the circuit resonance frequency point, by narrowband FFT analysis, thereby solving the problems of insufficient ripple detection precision and lack of frequency domain targeting, and providing a basis for accurate compensation.

[0051] 2) The application proposes a dual-channel dynamic compensation current mechanism. For the first channel ripple amplitude compensation, the real-time extracted ripple component time domain signal and the energy proportion in the preset frequency band are directly used as the compensation amount basis. The introduction of the energy proportion ensures that the compensation is targeted at the harmful ripple energy in the key frequency band. The compensation gain coefficient makes the compensation effect enhanced at deep dimming, effectively overcoming the problem of ripple suppression at low duty cycle. Meanwhile, the compensation polarity is dynamically adjusted according to the current error direction, ensuring the correct compensation direction. For the second channel trend leading compensation, the differential term of the error is introduced to predict the trend of the current change in advance, the absolute error is nonlinearly smoothed and limited by a hyperbolic tangent function, and the differential compensation weight coefficient and the adjustment threshold are combined, which can provide fast response when the error is large, and can avoid overshoot and oscillation when the error is close to the target, thereby significantly improving the dynamic response speed and stability of the system.

[0052] 3) After the dual-channel compensation current is superimposed, the generated ripple suppression current is smoothed by multi-stage adaptive filtering. This filtering method can dynamically adjust the filtering parameters according to the current working conditions such as the compensation amount and the ripple frequency characteristics, effectively filter out high-frequency burrs and noise, and at the same time, maximize the retention of system bandwidth and dynamic response capability, thereby solving the problem of response lag caused by fixed filtering. By accurately suppressing specific frequency bands, especially the human eye sensitive frequency band ripple and quickly tracking the target current, the visible flicker and brightness fluctuation of the LED light source are significantly reduced, and the visual comfort is greatly improved. The more stable and smaller ripple driving current also helps to prolong the service life of the LED and maintain the light color consistency.

[0053] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, but not limiting the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background, the drawings needed to be used in the embodiments of the present application or the background will be described below.

[0055] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments consistent with the present disclosure and serve to explain the technical solutions of the present disclosure together with the specification.

[0056] Figure 1 A flowchart of an output control method of an LED driving power supply provided by the embodiment of the present application;

[0057] Figure 2 A flowchart of a triple mechanism protection provided by the embodiment of the present application;

[0058] Figure 3 A structural diagram of an LED driving power supply provided by the embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to enable personnel in the technical field to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0060] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily mutually exclusive of other embodiments. It is explicitly understood that the embodiments described herein can be combined with each other.

[0061] Please refer to Figure 1 , Figure 1 A flowchart of an output control method of an LED driving power supply provided by the embodiment of the present application. As shown in Figure 1 , the method comprises:

[0062] S10, real-time acquisition of an output current signal of an LED lamp, high-frequency sampling is used to obtain a ripple component time-domain signal of the current;

[0063] S20, performing narrowband FFT analysis on the ripple component time-domain signal, and calculating an energy proportion of the ripple component time-domain signal in a preset frequency band;

[0064] S30, generating a reference current based on the target brightness, and calculating a double-channel dynamic compensation current according to the reference current, the ripple component time domain signal, and the energy proportion in the preset frequency band;

[0065] S40, superimposing the double-channel dynamic compensation current to the driving signal to generate a ripple suppression current, smoothing the ripple suppression current through multi-stage adaptive filtering, and driving the LED lamp according to the processed current signal.

[0066] In the field of LED driving power supply, the traditional output control method mainly focuses on "stabilizing the average current", and the core idea is to compare the average output current of the LED with the reference current corresponding to the target brightness, generate a compensation signal to adjust the driving current, and suppress the current fluctuation. The specific method is to use low frequency such as 50Hz-1kHz to sample the average current, and generate compensation through PI regulator to adjust the driving signal; or to smooth the current ripple through capacitor filtering or fixed parameter low pass filter to reduce the output fluctuation. However, the above methods have some defects: 1) only focusing on the average current, ignoring the high frequency component of the current ripple, which may cause high frequency flicker of LED light invisible to human eye but affecting camera shooting or long-term visual fatigue. 2) The fixed parameter filter or compensation algorithm cannot adapt to load change or input voltage fluctuation, and cannot adjust in real time when the ripple energy proportion changes, resulting in decrease of brightness stability. 3) The ripple energy of specific frequency band such as interference frequency band of sensitive equipment is not quantified, which is difficult to suppress specifically and may cause electromagnetic compatibility problem. Therefore, the present embodiment proposes a closed-loop control idea of "based on ripple component time domain analysis + double-channel dynamic compensation + multi-stage adaptive filtering" to solve the above problems, aiming at the defects of "heavy average, light ripple, lack of dynamics, and no targeting" of the prior art.

[0067] Specifically, in step S10, a high-frequency sampling module such as an ADC with a sampling rate of 10MHz is used to collect the output current in real time, and the average current component is subtracted from the total current through a subtracter to obtain the time domain signal of the pure ripple component, which contains high-frequency fluctuation information. The high-frequency sampling is much higher than the switching frequency, which can completely preserve the time domain characteristics of the ripple such as peak value, frequency and phase, providing original data for subsequent frequency domain analysis. If the sampling rate is insufficient, the ripple component will be distorted and the high-frequency fluctuation cannot be accurately reflected. By extracting the pure ripple component, the interference of the average current on the ripple analysis is avoided, and the total current is directly used for adjustment in the traditional method, the ripple signal is covered by the average amount and cannot be processed separately.

[0068] In step S20, narrowband FFT analysis is first performed, and the ripple component time domain signal is subjected to fast Fourier transform, but only focuses on a preset frequency band, such as 10 kHz-500 kHz, which is set according to the LED application scenario, such as the camera shooting needs to suppress 20 kHz-100 kHz, and the frequency spectrum leakage is reduced by adding a window function. The ripple energy ratio in the preset frequency band to the total ripple energy is calculated to quantify the ripple influence of the frequency band. The narrowband FFT analysis can accurately locate the frequency band that needs to be suppressed, avoiding the dynamic response delay caused by full-band filtering. If no narrowband analysis is performed, blindly suppressing the full-band ripple will increase the algorithm complexity and may filter useful signals. The energy ratio can reflect the “harmfulness” of the ripple in a specific frequency band, such as when the ratio exceeds 30%, it may cause flicker, providing a quantitative basis for the dynamic adjustment of the subsequent compensation amount. The traditional method has no energy quantification, and the compensation amount is a fixed value, which cannot adapt to the change of the ripple.

[0069] In step S30, the reference current is generated by table lookup or linear conversion according to the target brightness set by the user, such as the PWM dimming signal, which is used to reflect the average brightness demand.

[0070] In the traditional method, the current compensation method is mostly single-channel static compensation or single-dimensional dynamic compensation, which is specifically manifested as calculating the compensation amount based on a fixed ripple model, and the compensation parameter remains unchanged during system operation. For example, the compensation capacitance / inductance parameter is preset through a hardware filtering circuit, or the ripple compensation formula is fixed in the software, and only the ripple of the known frequency band is offset with a fixed amplitude. Another is to dynamically adjust only one dimension of the amplitude or trend of the ripple: if the amplitude is focused on, the instantaneous value of the ripple component is detected in real time, and the compensation current is generated through PI control to offset the amplitude fluctuation of the current ripple; if the trend is focused on, the compensation amount is adjusted to track the long-term trend according to the error accumulation of the reference current and the actual current, but the energy distribution difference of the ripple in the specific frequency band is ignored.

[0071] However, the above compensation methods have poor adaptability, response lag, insufficient precision and other problems, and cannot cope with the ripple frequency band drift caused by complex working conditions such as input voltage fluctuation, LED load aging, and environmental temperature change. Fixed parameters or single-dimensional adjustment will lead to insufficient compensation or overcompensation. Based only on the current or historical error adjustment, the response to the sudden change of the ripple such as the introduction of new frequency band ripple by high-frequency interference is slow, and compensation delay is easy to occur. Ignoring the energy ratio difference of the ripple in different frequency bands, such as the different effects of low-frequency ripple and high-frequency ripple on LED brightness, single compensation cannot consider multiple frequency band ripple suppression, resulting in high residual ripple of the output current and affecting the stability of the LED brightness.

[0072] ​In the embodiment, when calculating the double-channel dynamic compensation current, the ripple amplitude compensation of the first channel is calculated first, the specific frequency band ripple is inhibited, the compensation amplitude is dynamically calculated based on the energy proportion of the ripple component in the preset frequency band, the current PWM duty cycle and the time domain signal of the ripple component. For example: if the energy proportion of a certain frequency band is high, the compensation weight of the frequency band is preferentially enhanced, and the compensation response speed is adjusted in combination with the PWM duty cycle to avoid switch noise interference. In this way, the main energy of the current ripple can be immediately offset, and the high-frequency noise introduced by the switching power supply can be accurately suppressed. Then the trend lead compensation of the second channel is calculated, which is used to track the reference current trend. According to the absolute error of the reference current and the actual output current, the trend compensation gain coefficient, the lead compensation amount is calculated. For example: when the reference current suddenly increases due to the brightness adjustment instruction, the trend is predicted by the absolute error, and the compensation current is output in advance to avoid the "brightness lag" caused by the response delay. In this way, long-term trend deviation can be eliminated, and lead response can be achieved for LED load changes or reference current adjustment.

[0073] Therefore, through double-channel compensation, the first channel quickly offsets the high-frequency and burst ripple energy to avoid brightness flicker, and the second channel anticipates the reference current trend to avoid current drift caused by load changes. Through the "energy proportion" parameter to identify the main frequency band of the ripple, the amplitude compensation is more targeted, and the problem of poor adaptability of the prior art to frequency band drift is solved.

[0074] In step S40, the drive signal is superimposed with the double-channel compensation current to obtain a current signal with preliminarily suppressed ripple, the ripple suppression current is smoothed through multi-stage adaptive filtering, and the LED lamp is driven according to the processed current signal. The multi-stage filtering avoids the problem of "over-smoothing leading to slow response" or "insufficient suppression leading to ripple residue" of single filtering, and the adaptive parameter ensures optimal filtering effect at all times under different working conditions. The processed current signal not only meets the average brightness demand, but also greatly reduces the energy proportion of the preset frequency band, realizes "no flicker and high stability" of LED light emission, and reduces the risk of EMC interference.

[0075] Therefore, the above embodiment quantizes the energy proportion of the ripple in the preset frequency band through high-frequency sampling and narrowband FFT analysis, realizes "visual" analysis of the ripple, introduces time-domain and frequency-domain analysis of the ripple component into LED drive control, proposes "preset frequency band energy proportion" as the compensation basis, and realizes targeted suppression. In combination with the reference current, the real-time ripple signal and the frequency band energy proportion, the double-channel compensation current is generated, and in combination with the multi-stage adaptive filtering, the contradiction between "stably average brightness" and "suppressing high-frequency ripple" is solved, and the dynamic performance is superior to the traditional fixed algorithm. From "passive filtering" to "active analysis + dynamic compensation" closed-loop control, the brightness stability and anti-interference ability of the LED are improved.

[0076] In one embodiment, the reference current is generated based on the target brightness, and a double-channel dynamic compensation current is calculated according to the reference current, the ripple component time domain signal, and the energy proportion in the preset frequency band, including:

[0077] The ripple amplitude compensation of the first channel is calculated as follows:

[0078] ;

[0079] In the formula, is the ripple amplitude compensation, is the ripple compensation gain coefficient, , is the current PWM duty cycle; is the ripple component time domain signal; is the energy proportion of the ripple component time domain signal in the preset frequency band, which is calculated by the ratio of the preset frequency band ripple energy to the full frequency band ripple energy, and the value range is [0, 1]; is the reference current, is the actual output current; represents the compensation direction, and satisfies:

[0080] ;

[0081] In the above formula, is the ripple compensation gain coefficient, which is inversely proportional to the duty cycle . In the switching power supply, the inductor current ripple amplitude is proportional to , and the ripple is maximum when . The inverse ratio of design can dynamically adapt to the change of ripple amplitude. is the energy proportion of the ripple component time domain signal in the preset frequency band, which is calculated by the ratio of the preset frequency band ripple energy to the full frequency band ripple energy, for example, the energy proportion of the human eye sensitive frequency band 80Hz-200Hz is collected, and selective noise suppression is realized. For example, high-frequency switching noise ≈1, and low-frequency interference ≈0. The compensation polarity is determined according to the current error direction, so as to ensure that the compensation current always counteracts the error. is the absolute value of the ripple time domain signal, which provides a compensation reference.

[0082] The trend lead compensation of the second channel is calculated as follows:

[0083] ;

[0084] In the formula, is the trend lead compensation, This is the trend compensation gain coefficient, with a value range of [0.8, 1.2]. It is the hyperbolic tangent function. This represents the absolute error between the reference current and the actual output current. For non-linear adjustment threshold, Let be the differential compensation weight coefficient, and , This is the differential term of the error;

[0085] Determine the dual-channel dynamic compensation current:

[0086] ;

[0087] In the formula, It provides dual-channel dynamic compensation current.

[0088] In the above formula, The absolute error of the current is nonlinearly smoothed. When the numerator is much smaller than the denominator, the result is approximately linear; when the numerator is much larger than the denominator, the result is saturated to ±1 to avoid overcompensation under large errors. The introduced error differential term is used to predict the current change trend. For example, when the load suddenly increases... The compensation current is increased in advance. This is used to adjust the compensation intensity to adapt to different operating conditions. Finally, it integrates real-time ripple suppression and dynamic trend prediction to form a composite compensation.

[0089] To facilitate understanding, the following explanation uses a specific example of the Buck converter's operation:

[0090] Assume the Buck converter has an input voltage of 12V, an output voltage of 5V, and a switching frequency of 500kHz;

[0091] Ripple compensation channel: Duty cycle D = 5 / 12 = 0.42 ;

[0092] Ripple analysis: measured Energy percentage in the 500kHz band ;

[0093] Direction determination: , , ;

[0094] Output compensation: ;

[0095] Trend Compensation Channel: Parameters ;

[0096] Dynamic process: sudden load increase leads to from become ;

[0097] tanh term: ;

[0098] Output compensation: ;

[0099] Therefore, the total compensation is , which quickly offsets the error and suppresses the ripple.

[0100] The double-channel dynamic compensation current mode provided by the embodiment has the first channel ripple amplitude compensation The first channel is directed to compensate for the switching frequency ripple, which can reduce the output current THD by more than 30%; the second channel is trend leading compensation The differential term predicts the load change direction, which shortens the response time of the step load by more than 40%; The compensation is stable at different duty cycles, The function avoids overshoot under large error and improves robustness. Through the cooperation of the double channels, the output current ripple is reduced and the load state recovery time is shortened in the wide duty cycle range and high dynamic load scenarios, through time-frequency domain joint analysis and nonlinear predictive control, the contradiction between ripple suppression and dynamic response in the switching power supply is solved.

[0101] In a preferred embodiment, the method further comprises self-adapting the trend compensation gain coefficient:

[0102] ;

[0103] In the formula, is the trend compensation gain coefficient, is the calibration parameter, is the current PWM duty cycle, is a natural constant.

[0104] Generally speaking, if a fixed There may be the following defects: large ripple noise interferes with the trend compensation signal, resulting in overshoot; when D approaches 0 or 1, the system nonlinearity is enhanced, and a single gain cannot balance speed and stability. When increases, tends to When the ripple is large, the trend compensation is enhanced to resist the response lag caused by noise interference, and when decreases, tends to 0, which can ensure that small ripples avoid excessive compensation and cause oscillation. When the duty cycle tends to 0 or 1, the system gain nonlinearity changes sharply, and the real-time correction Maintain the stability of the whole working area. The adaptive adjustment scheme breaks through the speed-stability contradiction of traditional fixed gain by coupling the design of ripple amplitude exponential mapping and duty cycle linear compensation, and realizes self-optimization of all working conditions with 3 parameters, which is significantly better than complex adaptive algorithms.

[0105] Referring to Figure 2 In one embodiment, the method further comprises:

[0106] determining whether the current PWM duty cycle is less than a first preset value, and if the current PWM duty cycle is less than the first preset value, performing dynamic adjustment of the constant current circuit, including:

[0107] calculating a real-time current saturation critical value, and if the ratio of the peak value of the actual output current to the current saturation critical value exceeds a second preset value, triggering a triple protection mechanism; the triple protection mechanism includes increasing the switching frequency, injecting a high-frequency dithering signal to disperse electromagnetic energy, and dynamically limiting the current.

[0108] In this embodiment, Dth1 is the duty cycle preset threshold, and the typical value is 0.1-0.2; Kth2 is the current peak safety factor, and the typical value is 0.8-0.9; the current saturation critical value is Isat.

[0109] First, calculate the size of Isat:

[0110] ;

[0111] In the formula, is the saturation magnetic flux density of the magnetic core, is the effective cross-sectional area of the magnetic core, is the effective cross-sectional area of the inductor, is the inductance, is the real-time magnetic core temperature, obtained by NTC; is the maximum allowable operating temperature of the magnetic core. The term can correct the saturation current derating at high temperature in real time.

[0112] When the triple protection mechanism is triggered:

[0113] 1) Increase the switching frequency:

[0114] ;

[0115] In the formula, are the frequencies after and before adjustment respectively, is the frequency adjustment coefficient, default 0.2-0.5, is the ratio of the peak value of the actual output current to the current saturation critical value.

[0116] 2) Inject a high-frequency dithering signal:

[0117] The injection signal size is 2 to 5 times The energy is dispersed to different frequency bands to avoid exceeding a single frequency point.

[0118] 3) Dynamic current limiting:

[0119] The dynamic threshold size is The product of the safety factor and , the decay rate, is a natural constant, is time.

[0120] The traditional method usually uses a fixed current threshold that cannot adapt to the temperature / aging-induced drift. Simply increasing the frequency can cause EMI of the new frequency point to exceed the standard, and the current limiting response is usually a hard shutdown, which can cause voltage collapse. In this embodiment, magnetic saturation prevention precision can be improved, real-time calculation and temperature parameters are associated to solve the problem of excessive or insufficient margin in traditional solutions. High-frequency dithering injection reduces EMI peaks by 10 dB without adding additional filters, achieving EMI and efficiency co-optimization; exponential decay current limiting avoids output voltage drop, and finally realizes three-dimensional optimization of safety boundaries, efficiency, and EMI in low-duty-cycle, high-power-density application scenarios, providing core protection for high-reliability power systems.

[0121] In LED lighting / display systems, low-frequency ripple current-induced flicker can cause:

[0122] Visual fatigue: the human eye is most sensitive to the 80-300Hz frequency band;

[0123] Health risks: epilepsy patients are prone to symptoms when exposed to 15-70Hz flashes;

[0124] If a fixed frequency band compensation is used, such as 100-500Hz, it cannot adapt to changes in environmental brightness, such as a decrease in sensitive frequency bands in dark environments. Directly using full-band suppression can increase system power consumption by more than 20%, i.e., no difference between high-frequency compensation and amplification. Therefore, this embodiment will combine environmental brightness classification and establish a sensitive frequency band mapping, and dynamically adjust the size of the preset frequency band according to the flicker sensitivity function.

[0125] Preferably, in one embodiment, the preset frequency band is the human eye's visual sensitivity frequency band, and the value range is dynamically optimized by a visual model, including:

[0126] Different human eye visual sensitivity frequency bands are divided according to environmental brightness;

[0127] A flicker sensitivity function is constructed to update the divided human eye visual sensitivity frequency band according to the flicker sensitivity; wherein the flicker sensitivity function is as follows:​

[0128] ;

[0129] wherein, is the stroboscopic sensitivity, is the most sensitive frequency, which is 100Hz by default, is the bandwidth factor, is the frequency, is the maximum sensitivity of the human eye.

[0130] Table 1 Relationship between ambient brightness and sensitive frequency band of human eye

[0131]

[0132] According to Table 1, under different ambient brightness, the corresponding sensitive frequency band of the human eye is different, for example, when the ambient brightness is dark, the most sensitive frequency band is also low, and as the brightness increases, the most sensitive frequency band will also increase.

[0133] In order to dynamically update the compensation frequency band, first, the light intensity value is collected in real time by the brightness sensor, and then the curve is calculated, the frequency point energy is requested, after the frequency band is scanned from 50 to 1000Hz, the frequency point energy is returned, and is sent, and the minimum frequency value and the maximum frequency value are dynamically adjusted by the compensator, so as to update the value range of the preset frequency band. For example, for different scenes, the traditional method will adopt a fixed frequency band, while the present scheme can provide different dynamic frequency bands for different scenes. The sensitive frequency band suppression effect is significantly improved. Therefore, by the method of the embodiment, the human eye vision model is embedded into the control system through the function, which realizes the priority suppression of low-frequency ripple in dark environment and focuses on high-frequency ripple in bright environment; and the dynamic contraction of the compensation frequency band can reduce the invalid high-frequency compensation current.

[0134] In one embodiment, the method further comprises:

[0135] When it is detected that the current duty cycle is lower than the third preset value and the duration exceeds the preset time length, the mixed dimming mode is switched to, and the retinal protection algorithm is activated to limit the current ripple peak-to-peak value in the preset range; in the mixed dimming mode, the PWM duty cycle is fixed at 0.25, and the brightness is supplemented by analog dimming.

[0136] In low-frequency PWM, when D < 0.1, the switching period is lengthened, and the ripple frequency enters the sensitive area of the human eye. If pure PWM dimming is used, high flicker problems will occur when D < 0.1, and if pure analog dimming is used, although the flicker risk is reduced to some extent, the LED color coordinate drift problem will occur. Therefore, the embodiment adopts a hybrid dimming mode. In the hybrid dimming process, the PWM duty cycle is first set to 0.25, and then analog dimming compensation is performed, including first determining the brightness target value mapping, determining the actual output according to the PWM contribution value (weight 0.25) and the analog dimming contribution (weight 0.75), and adjusting the analog current. Then, a double-channel hybrid calibration is adopted. The LED color coordinates are monitored in real time by the RGB sensor, and the analog current is dynamically corrected to make the color coordinate offset meet the conditions.

[0137] In addition, the retina protection algorithm can be performed in two aspects, one is to limit the peak-to-peak value of the ripple to be less than a threshold, and the other is to use a dynamic suppression method, including injecting an inverse ripple current to offset the original ripple to achieve feedforward compensation, adjusting the PWM slope compensation in real time to achieve PID adaptive adjustment, and adding a virtual resistance at the LC resonance point. Through hybrid dimming, the 0.25 duty cycle can lock the ripple fundamental frequency to the safe area, and through analog dimming compensation, the low brightness range can be expanded without color drift. Through the retina protection algorithm, the peak-to-peak value of the ripple can be compressed, and through exponential decay limiting, the visual cells can be protected from strong stimulation.

[0138] In one embodiment, the ripple suppression current is smoothed by multi-stage adaptive filtering, including:

[0139] According to the current dimming duty cycle Select the filter cutoff frequency:

[0140] ;

[0141] In the formula, is the filter cutoff frequency, is the attenuation coefficient, and , is the current PWM duty cycle, is the natural constant; , are the minimum cutoff frequency and the maximum cutoff frequency, respectively;

[0142] A switchable capacitor array is used to dynamically adjust the LC filter parameters to match the cutoff frequency.

[0143] The typical value of is 200-500 Hz, with a safety margin to avoid oscillation caused by filter phase shift. The current build-up time < 100 μs needs to be ensured at more than 10 times the PWM frequency, The rapid pressure drop is ensured when D < 0.3, The greater, the lower the brightness The closer .

[0144] If the traditional LC filter adopts a fixed cutoff frequency, it will face a dilemma: when the PWM duty cycle D is small (low brightness), if the cutoff frequency is too high, the filter cannot effectively filter out low-frequency ripples, resulting in large current fluctuations and light flickering; if the cutoff frequency is too low, although the ripple suppression effect is good, when the duty cycle changes rapidly, the current build-up time is too long, which will cause response lag, and even cause system oscillation due to too large phase shift. When D is large (high brightness), if the cutoff frequency is too low, it will limit the rapid establishment of current and cannot meet the dynamic needs of high-frequency PWM.

[0145] The principle of this scheme is based on the correlation between PWM duty cycle and filtering requirements: low duty cycle requires stronger low-frequency filtering capability (low cutoff frequency), and high duty cycle requires faster dynamic response (high cutoff frequency). Through the formula , adaptive adjustment of the cutoff frequency is realized, where The exponential characteristic is the key when , the value of is large, and the exponential term decays rapidly, making rapidly close to to ensure strong filtering at low brightness; when increases, the value decreases, and the exponential term tends to 1, close to to meet the fast response at high brightness. The value of further optimizes the filtering characteristics in the low brightness range, The greater, the lower the duty cycle drops more rapidly, and enters the strong filtering state earlier.

[0146] To determine the size of , mainly through two parts: one is to calculate the target cutoff frequency according to the real-time PWM duty cycle D through the above formula; the other is to use a switchable capacitor array to dynamically adjust the capacitance value of the LC filter. When the inductance L is fixed, by switching different capacitance values C, the cutoff frequency can be changed, so that the actual cutoff frequency matches the calculated . At the same time, the preferred value is 200-500 Hz, with a safety margin to avoid system oscillation due to too large filter phase shift;Higher than 10 times of PWM frequency, ensure the current build-up time less than 100us, meet the high frequency dynamic response requirement. In low brightness, Close to the low frequency ripple can be effectively suppressed, avoiding the light flicker; in high brightness, Close , ensure the current quickly build-up, fast response without lag; through adjustment can flexibly optimize the filter characteristics in low brightness interval, adapt to different scene requirements; at the same time, the design of switchable capacitor array makes the filter parameter adjustment convenient, compatible with wide range PWM dimming, finally realize low ripple, fast response in full brightness range, and high system stability, no risk of oscillation.

[0147] In one embodiment, the switchable capacitor array includes a first capacitor, a second capacitor and a third capacitor;

[0148] Wherein, the ratio of the second capacitor to the first capacitor is equal to the ratio of the third capacitor to the second capacitor;

[0149] When the filter cutoff frequency is greater than 10KHz, the first capacitor is enabled;

[0150] When the filter cutoff frequency is greater than 1KHz and less than or equal to 10KHz, the first capacitor and the second capacitor are enabled;

[0151] When the filter cutoff frequency is less than or equal to 1KHz, the first capacitor, the second capacitor and the third capacitor are enabled.

[0152] The embodiment adopts a switchable capacitor array, in order to make the cutoff frequency of the LC filter accurately match the requirements of different intervals in multi-stage adaptive filtering, realize the dynamic switching of filter parameters through stepwise adjustment of capacitor value, solve the problem that fixed capacitor value cannot cover wide range cutoff frequency adjustment, at the same time, simplify the control logic and reduce the hardware cost.

[0153] If a single capacitor or capacitor combination with irregular ratio is adopted, either it is difficult to cover the wide range cutoff frequency adjustment from to , or it will cause the cutoff frequency to jump too much when the capacitor is switched, causing current fluctuation or response mutation. When there is a geometric relationship between capacitors, the cutoff frequency can be adjusted in geometric steps through combination switching, which is more consistent with the characteristics of continuous change with duty cycle D, avoiding performance fluctuations caused by parameter mutation.

[0154] First, determine the capacitor ratio, according to to The range calculation capacitor ratio, for example, if Need more than 10KHz, the middle interval is 1KHz-10KHz, low interval is less than or equal to 1KHz, through the capacitor ratio design to make the three kinds of combination of cut-off frequency just cover the three intervals. Hardware using switchable capacitor array, through the MOS tube and other switching devices control C1, C2, C3 access state: when >10KHz, only close the switch of C1, the total capacitance is C1; when 1KHz ≤10KHz, close the switch of C1 and C2, the total capacitance is C1+C2; when ≤1KHz, close the switch of the three capacitors at the same time, the total capacitance is C1+C2+C3. Control logic according to the real-time calculation Value, trigger the corresponding switch combination, realize the dynamic switching of capacitor value.

[0155] Through this embodiment, first, through the stepped capacitor switching, precise matching of different interval cut-off frequency requirements, avoid single capacitor in the performance of the wide range of light; Second, the equal ratio capacitor design makes the cut-off frequency switching smooth, reduces the current fluctuation or response shock caused by parameter mutation; Third, only three capacitors can cover high, medium and low frequency intervals, while ensuring performance, simplify the hardware structure, reduce the cost; Four, with the adaptive cut-off frequency algorithm before, further improve the ripple suppression effect and dynamic response speed in the full brightness range, through the low cut-off frequency of multiple capacitor combination in low brightness, ensure small ripple, no flicker, through the single capacitor to realize the high cut-off frequency in high brightness, ensure fast response, no lag.

[0156] In summary, the method provided by the embodiments of the present application can at least achieve the following effects:

[0157] 1) The present application obtains the current ripple component time domain signal through high frequency sampling, and uses narrowband FFT analysis to calculate the energy proportion in the preset key frequency band, such as the human eye sensitive frequency band or the circuit resonance point, solves the problems of insufficient ripple detection precision and lack of frequency domain pertinence, and provides a basis for accurate compensation.

[0158] 2) This application proposes a dual-channel dynamic current compensation mechanism. For the first channel ripple amplitude compensation, the real-time extracted ripple component time-domain signal and its energy proportion in the preset frequency band are directly used as the basis for the compensation amount. Introducing the energy proportion ensures that the compensation targets the harmful ripple energy in the key frequency band. The compensation gain coefficient enhances the compensation effect during deep dimming, effectively overcoming the problem of ripple suppression at low duty cycles. At the same time, the compensation polarity is dynamically adjusted according to the direction of the current error to ensure the correct compensation direction. For the second channel trend advance compensation, the differential term of the error is introduced to predict the current change trend in advance. The absolute error is nonlinearly smoothed and limited by the hyperbolic tangent function. Combined with the differential compensation weight coefficient and adjustment threshold, it can provide a fast response when the error is large, and avoid overshoot and oscillation when the error is close to the target, significantly improving the dynamic response speed and stability of the system.

[0159] 3) This application superimposes the dual-channel compensation currents and smooths the generated ripple suppression current through multi-level adaptive filtering. This filtering method can dynamically adjust the filtering parameters according to the current operating conditions, such as the magnitude of the compensation and the ripple frequency characteristics. While effectively filtering out high-frequency glitches and noise, it maximizes the preservation of system bandwidth and dynamic response capabilities, solving the problem of response lag caused by fixed filtering. By precisely suppressing ripple in specific frequency bands, especially those sensitive to the human eye, and rapidly tracking the target current, the visible flicker and brightness fluctuations of the LED light source are significantly reduced, greatly improving visual comfort. A more stable driving current with lower ripple also helps extend the lifespan of the LED and maintain color consistency.

[0160] To facilitate understanding of the output control method provided in this application, the following will illustrate it using two specific scenarios:

[0161] Scenario 1: Compensation against sudden interference in surgical shadowless lamp scenarios:

[0162] When operating room lights are turned on or off by electrosurgical equipment such as high-frequency electrosurgical units, the sudden change in grid voltage causes millisecond-level spike ripples in the LED current. Traditional PID control cannot suppress such sudden changes due to response delay, resulting in flickering in the surgical field.

[0163] In this scenario, based on the existing high-frequency sampling provided in the above embodiments, a power grid voltage gradient detection circuit is added to calculate the first derivative of the power grid voltage with respect to time in real time. If it is determined to be a start-up or shutdown event of the electrosurgical equipment, an anti-sudden event mode is triggered. At this time, the first channel is enhanced, and the ripple compensation gain coefficient can be optimized to satisfy:

[0164] ;

[0165] in, This is a sudden disturbance factor; when the first derivative of the grid voltage with respect to time is greater than 0, 1 otherwise.

[0166] When burst interference is detected, the LC filter cutoff frequency temporarily raised to 2 , realized by the aforementioned full-parallel capacitor array, sacrificing part of the smoothness for millisecond-level response speed; after the interference ends, the adaptive filter parameters are restored, and the transient light fluctuation is compensated by the retina protection algorithm. In this way, the peak-to-peak value of the LED ripple during the start-stop of the electrosurgical equipment will be reduced, and the response delay will be shortened, avoiding the risk of stroboscopic effect in the surgical field of view.

[0167] Scenario two, dynamic spot stability control of stage follow spot:

[0168] When the stage follow spot moves quickly, the current ripple in the low duty cycle range of PWM dimming is perceived by the human eye as spot jitter, and the existing technology cannot solve the brightness lag caused by motion acceleration.

[0169] In this scenario, the real-time motion acceleration of the lamp can be obtained, and a motion-brightness coupling model is constructed: the acceleration is mapped to a trend compensation gain coefficient:

[0170] ;

[0171] In the formula, is the maximum design acceleration, is the value calculated under the method provided in the foregoing embodiment.

[0172] In addition, dynamic optimization can also be performed on hybrid dimming, which can reduce the perception of spot jitter and improve brightness lag by considering motion characteristics, meeting the high-speed follow light demand.

[0173] Referring to Figure 3 In one embodiment, the present application also provides an LED driving power supply suitable for the output control method of the LED driving power supply according to any one of the first aspect, comprising:

[0174] A high-frequency sampling module 100 is configured to obtain a ripple component time domain signal of the current by high-frequency sampling;

[0175] A dynamic compensation engine 200 is configured to calculate a double-channel dynamic compensation current according to the ripple component time domain signal;

[0176] A control chip 300 is configured to superimpose the double-channel dynamic compensation current on the driving signal to generate a ripple suppression current;

[0177] An adaptive filter bank 400 including a magnetic bead filter and a switchable capacitor array is configured to perform smoothing processing on the ripple suppression current by multi-stage adaptive filtering to drive the LED lamp.​

[0178] In the high-frequency sampling module 100, the current sampling circuit collects the output current signal of the LED lamp set in real time, and after removing the noise through the signal conditioning circuit, inputs the high-frequency sampling module. The high-frequency sampling module performs oversampling on the current signal through the high-speed ADC to obtain the original time-domain signal containing high-frequency ripple. The average current component extracted through the sliding window algorithm is subtracted from the original signal to obtain the pure ripple component time-domain signal, which is output to the dynamic compensation engine and the narrowband FFT analysis unit.

[0179] The dynamic compensation engine 200 inputs parameters including the ripple component time-domain signal, the preset frequency band energy proportion, the reference current, the absolute error of the actual output current and the reference current, and the current PWM duty cycle. Through the calculation of the ripple amplitude compensation of the first channel and the trend advance compensation of the second channel respectively, the problem of insufficient precision of traditional single-channel compensation is solved through the synergy of “immediate amplitude suppression + trend advance adjustment”.

[0180] The control chip 300 is used for receiving the original driving signal and the double-channel dynamic compensation current, superimposing the compensation current on the original driving signal to generate a ripple suppression current, outputting the ripple suppression current to the adaptive filter bank, and feeding back the current PWM duty cycle to the dynamic compensation engine in real time. Real-time fusion of compensation current and driving signal is realized to provide optimized current signal for subsequent filtering.

[0181] The adaptive filter bank 400 includes a magnetic bead filter, which uses high-impedance magnetic beads to provide resistive attenuation for high-frequency ripple above 100 kHz. A switchable capacitor array is composed of a plurality of ceramic capacitors with different capacitance values and MOS tube switches, and the number of capacitors connected is controlled by the control chip. The first stage is magnetic bead filtering, and the ripple suppression current is first filtered by the magnetic bead filter to preliminarily attenuate high-frequency ripple, especially switch frequency harmonics, reducing the burden of subsequent capacitor filtering. The second stage is a switchable capacitor array, and the control chip dynamically switches the capacitance value of the capacitor array according to the energy proportion output by the narrowband FFT analysis unit. For example, when the energy proportion of high-frequency ripple is large, a larger capacitance is connected to enhance filtering; when the proportion is small, the capacitance is reduced to improve the dynamic response. Combining the high-frequency suppression capability of the magnetic bead and the dynamic adjustability of the capacitor array, the “high-frequency precise filtering + response speed adaptation” is realized to solve the contradiction of “insufficient suppression” or “response lag” of traditional fixed filtering.

[0182] The above is all the embodiments disclosed in the present application, and those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software mode depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

Claims

1. An output control method for an LED driver power supply, characterized in that, The method includes: The output current signal of the LED lamp is acquired in real time, and the time-domain signal of the current ripple component is obtained through high-frequency sampling. Perform narrowband FFT analysis on the ripple component time-domain signal to calculate the energy proportion of the ripple component time-domain signal in the preset frequency band; A reference current is generated based on the target brightness. The dual-channel dynamic compensation current is calculated based on the reference current, the ripple component time-domain signal, and the energy percentage in a preset frequency band, including: Calculate the ripple amplitude compensation for the first channel: ； In the formula, For ripple amplitude compensation, This is the ripple compensation gain coefficient. , This represents the current PWM duty cycle. The ripple component is the time-domain signal. The energy proportion of the ripple component time-domain signal in the preset frequency band is calculated by the ratio of the ripple energy in the preset frequency band to the ripple energy in the full frequency band, with a value range of [0,1]. As the reference current, This refers to the actual output current. Indicates the direction of compensation, satisfying: ； Calculate the trend lead compensation for the second channel: ； In the formula, To compensate for the trend ahead of time, This is the trend compensation gain coefficient, with a value range of [0.8, 1.2]. It is the hyperbolic tangent function. This represents the absolute error between the reference current and the actual output current. For non-linear adjustment threshold, Let be the differential compensation weight coefficient, and , This is the differential term of the error; Determine the dual-channel dynamic compensation current: ； In the formula, Dual-channel dynamic current compensation; The dual-channel dynamic compensation current is superimposed on the drive signal to generate ripple suppression current. The ripple suppression current is smoothed by multi-level adaptive filtering, and the LED is driven according to the processed current signal.

2. The output control method for an LED driver power supply according to claim 1, characterized in that, The method further includes adaptive adjustment of the trend compensation gain coefficient: ； In the formula, This is the trend compensation gain coefficient. For calibration parameters, This represents the current PWM duty cycle. It is a natural constant.

3. The output control method for an LED driver power supply according to claim 1, characterized in that, The method further includes: Determine if the current PWM duty cycle is less than a first preset value. If the current PWM duty cycle is less than the first preset value, perform dynamic adjustment of the constant current circuit, including: Calculate the real-time current saturation threshold. If the ratio of the peak value of the actual output current to the current saturation threshold exceeds the second preset value, a triple protection mechanism is triggered. The triple protection mechanism includes increasing the switching frequency, injecting a high-frequency jitter signal to disperse electromagnetic energy, and dynamic current limiting.

4. The output control method for an LED driver power supply according to claim 1, characterized in that, The preset frequency band is a frequency band sensitive to human vision, and its value range is dynamically optimized through a visual model, including: Different frequency bands that are sensitive to human vision are divided according to ambient brightness; A flicker sensitivity function is constructed, and the pre-defined human visual sensitivity frequency bands are updated based on the magnitude of the flicker sensitivity. The flicker sensitivity function is as follows: ； In the formula, For flicker sensitivity, The most sensitive frequency, the default is 100Hz. For bandwidth factor, For frequency, The human eye has the greatest sensitivity.

5. The output control method for an LED driver power supply according to claim 1, characterized in that, The method further includes: When the current duty cycle is detected to be lower than the third preset value and the duration exceeds the preset duration, the system switches to hybrid dimming mode and activates the retinal protection algorithm to limit the peak value of the current ripple within the preset range. In the hybrid dimming mode, the PWM duty cycle is fixed at 0.25 and the brightness is supplemented by analog dimming.

6. The output control method for an LED driver power supply according to claim 1, characterized in that, The smoothing of ripple suppression current through multi-level adaptive filtering includes: Based on the current dimming duty cycle Select the filter cutoff frequency: ； In the formula, This is the filter cutoff frequency. The attenuation coefficient is, and , The current duty cycle is PWM. It is a natural constant; , These are the minimum cutoff frequency and the maximum cutoff frequency, respectively. A switchable capacitor array is used to dynamically adjust the parameters of the LC filter to match the cutoff frequency.

7. The output control method for an LED driver power supply according to claim 6, characterized in that, The switchable capacitor array includes a first capacitor, a second capacitor, and a third capacitor; The ratio of the second capacitor to the first capacitor is equal to the ratio of the third capacitor to the second capacitor. When the filter cutoff frequency When the frequency is greater than 10kHz, the first capacitor is activated; When the filter cutoff frequency When the frequency is greater than 1kHz and less than or equal to 10kHz, the first and second capacitors are activated. When the filter cutoff frequency When the frequency is less than or equal to 1kHz, the first capacitor, the second capacitor, and the third capacitor are activated.

8. An LED driver power supply, applicable to the output control method of the LED driver power supply as described in any one of claims 1-7, characterized in that, include: The high-frequency sampling module is used to acquire the time-domain signal of the ripple component of the current through high-frequency sampling. The dynamic compensation engine is used to calculate the dual-channel dynamic compensation current based on the time-domain signal of the ripple component. The control chip is used to superimpose the dual-channel dynamic compensation current onto the drive signal to generate ripple suppression current. An adaptive filter bank, including a ferrite bead filter and a switchable capacitor array, is used to smooth ripple suppression current through multi-stage adaptive filtering to drive LED lights.

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