A constant current detection and control circuit for a DC-DC LED dimming power supply

Abstract

The present invention relates to the technical field of LED lighting, and provides a constant current detection control circuit and device for a DC-DC LED dimming power supply. It includes: a MOS driving module, which is used to receive a dimming control signal and generate a driving voltage; a BUCK bucking module, which is used to buck the driving voltage to generate an equivalent voltage signal; a peak current acquisition module, which is used to transmit the LED output current to an MCU processor to determine a driving pulse width correction signal; a current compensation calculation module, which is used to determine a compensation control signal according to the driving pulse width correction signal. The present invention uses an MCU as a control chip and an independent programming method, in cooperation with a corresponding peripheral acquisition circuit, to replace a driving control circuit with a BUCK driving IC as the core, so as to improve the flexibility of the BUCK driving application design without being limited by the inherent defects of the driving chip.

Description

Technical Field

[0001] The present invention relates to the field of power supply detection, and particularly to a constant current detection and control circuit for a DC-DC LED dimming power supply. Background Art

[0002] Currently, as Figure 3 shown, in the traditional LED-driven BUCK constant current control method, a constant current buck driving IC is used for control. During the process of the IC controlling the bucking of the BUCK circuit, the output current is sampled through an external resistor. The current flowing through this resistor is multiplied by the resistor to obtain an equivalent voltage, which is compared with the current equivalent voltage set by the comparator unit inside the IC, thereby forming a current closed-loop feedback loop to achieve the purpose of constant current control. Through an external control signal (PWM signal, analog voltage signal), the value of this current equivalent voltage can be changed, thereby controlling the magnitude of the output current of the BUCK circuit and achieving the purpose of adjusting the LED light output brightness by the LED power supply.

[0003] In the traditional solution, the driving current of the BUCK circuit is completely controlled by the BUCK driving IC. In the circuit application scenario, there are many limitations, and it is impossible to deal with the internal defects of the driving IC, such as low brightness step sense and output current jitter problem during fixed-point dimming, by adjusting external circuit parameters during the design process. Summary of the Invention

[0004] A constant current detection and control circuit for a DC-DC LED dimming power supply according to the present invention is used to solve the situation that the driving current of the BUCK circuit is completely controlled by the BUCK driving IC, and there are many limitations in the circuit application scenario, and it is impossible to deal with the internal defects of the driving IC, such as low brightness step sense and output current jitter problem during fixed-point dimming, by adjusting external circuit parameters during the design process.

[0005] The present invention provides a constant current detection and control circuit for a DC-DC LED dimming power supply, including:

[0006] A MOS driving module; for receiving a dimming control signal and generating a driving voltage;

[0007] A BUCK bucking module; for bucking the driving voltage to generate an LED output current;

[0008] A peak current acquisition module: for transmitting the LED output current to the MCU processor to determine a driving pulse width correction signal;

[0009] A current compensation calculation module: for determining a compensation control signal according to the driving pulse width correction signal.

[0010] Further, the peak current acquisition module includes:

[0011] A signal amplification circuit for receiving an equivalent voltage signal and converting it to a preset voltage range;

[0012] A comparator for comparing the LED output current with a desired current value and outputting a comparison signal; wherein the desired current value signal is sent by the MCU processor.

[0013] Further, the comparison signal includes a first signal and a second signal;

[0014] Wherein, when the comparison signal is the first signal, the LED output current is higher than the desired current value, and the comparator outputs a rising edge signal;

[0015] Wherein, when the comparison signal is the second signal, the LED output current is lower than the desired current value, and the comparator outputs a falling edge signal.

[0016] Further, the signal amplification circuit includes: an eleventh resistor, a tenth resistor, a ninth resistor, an eighth resistor, a seventh resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, a fifth resistor, a third capacitor and a signal amplifier;

[0017] One end of the eleventh resistor is used to collect the LED output current and is connected to the positive input terminal of the signal amplifier through the seventh resistor;

[0018] The other end of the eleventh resistor is connected to the negative input terminal of the signal amplifier through the eighth resistor;

[0019] The eleventh resistor is connected in parallel with the tenth resistor and the ninth resistor;

[0020] The negative input terminal of the signal amplifier is also grounded through the fourth capacitor, and the positive input terminal of the signal amplifier is also grounded through the fifth capacitor;

[0021] The negative input terminal and the output terminal of the signal amplifier are connected in parallel with a fifth resistor, and the negative input terminal and the output terminal are also connected in parallel with a series-connected third capacitor and a sixth resistor.

[0022] Further, the PA2 terminal of the comparator is electrically connected to the output terminal of the signal amplification circuit through a fourth resistor, and the PA0 terminal of the comparator is electrically connected to the MCU processor through a second-order RC filter circuit and receives the PWM wave sent by the MCU processor, wherein the PWM wave is equivalent to the desired current value;

[0023] The output terminal of the comparator is electrically connected to the MCU processor for outputting a driving pulse width correction signal.

[0024] Further, the secondary RC filter circuit includes: a first resistor, a second resistor, and a third resistor connected in series, wherein a twelfth resistor and a first capacitor connected in series are connected in parallel to the second resistor; a second capacitor grounded is connected between the third resistor and the PA0 port of the comparator.

[0025] Further, the process of passing the LED output current through the MCU processor further includes:

[0026] Based on the LED output current interruption, generate a peak-shaped current distribution curve, and extract the signal timing and amplitude characteristics of each peak and each valley through the peak-valley algorithm;

[0027] According to the peak-shaped current distribution curve, perform LED current signal conversion, and perform VMD decomposition after conversion to determine the dispersion entropy values of each peak and each valley;

[0028] Input the dispersion entropy value and the signal timing into the first PAC model to determine whether the LED output current corresponding to the signal timing needs to be compensated;

[0029] Among them, when the LED output current corresponding to the signal timing needs to be compensated, input the dispersion entropy value and the amplitude characteristics into the second PAC model to determine the correction value of the LED output current demand corresponding to the signal timing.

[0030] Further, the determination of whether the LED output current corresponding to the signal timing needs to be compensated includes the following steps:

[0031] Input the dispersion entropy value into the first PAC model according to the signal timing to determine the nature characteristics of the LED current for each signal timing;

[0032] Based on the signal timing, calculate the fluctuation data of the LED current at different signal timings;

[0033] According to the fluctuation data and the expected current value, judge the long-range correlation of the LED current;

[0034] Among them, when the LED current belongs to the expected negative correlation, it means that the LED output current needs to be corrected;

[0035] Among them, when the LED current belongs to the expected positive correlation, it means that the LED output current does not need to be corrected;

[0036] Among them, when the LED current has no expected correlation, it means that the MOS drive module has a drive fault.

[0037] Further, the determination of whether the LED output current corresponding to the signal timing needs to be compensated further includes:

[0038] Input the LED output current and the spread entropy value at each moment into the second PAC model to determine the compensation interval of the LED output current at each moment;

[0039] Determine the adjustable curve of the LED output current according to the compensation interval;

[0040] Determine whether there is a deviation value beyond the compensation interval when the LED output current is compensated to the desired current value according to the adjustable curve and the desired current value;

[0041] Among them, when there is a deviation value, determine the moment when the deviation value appears, and determine whether the driving current of the MOS driving module is abnormal. When the driving current of the MOS driving module is abnormal, control the MOS driving module to reset;

[0042] Among them, when there is no deviation value, determine the correction value corresponding to each moment.

[0043] Furthermore, the determination of the compensation control signal includes:

[0044] Preset a desired equivalent network;

[0045] Input the driving pulse width correction signal into the desired equivalent network for equivalent calculation to determine the capacitance and inductance parameter values at each moment;

[0046] Perform fitting calculation on the capacitance and inductance parameter values at each moment and the preset constant current compensation condition to determine the fitting value corresponding to the fitting calculation;

[0047] Convert the fitting value into a compensation control signal to compensate the dimming control signal.

[0048] The beneficial effects of the present invention are as follows:

[0049] The MCU of the present invention can accurately collect the actual output current magnitude, make a correct judgment according to the result of comparison with the desired output current magnitude, and can correctly control the on and off of the BUCK driving waveform to achieve the purpose of constant output current.

[0050] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification, or be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures specifically pointed out in the written specification and the drawings.

[0051] The technical solutions of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0052] The accompanying drawings are used to provide a further understanding of the present invention and form a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention.

[0053] In the accompanying drawings:

[0054] Figure 1 It is a composition diagram of a constant - current detection and control circuit for a DC - DC LED dimming power supply in an embodiment of the present invention;

[0055] Figure 2 It is the peak - current acquisition circuit corresponding to the peak - current acquisition module in an embodiment of the present invention;

[0056] Figure 3 It is a traditional circuit composition diagram of a constant - current detection and control circuit for a DC - DC LED dimming power supply in an embodiment of the present invention. Detailed implementation manners

[0057] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0058] As Figure 1 shown, this embodiment provides a constant - current detection and control circuit for a DC - DC LED dimming power supply, which is characterized by including:

[0059] A MOS driving module; used to receive a dimming control signal and generate a driving voltage;

[0060] A BUCK buck - down module; used to perform buck - down processing on the driving voltage to generate an LED output current;

[0061] A peak - current acquisition module: used to transmit the LED output current to the MCU processor to determine a driving pulse - width correction signal;

[0062] A current compensation calculation module: used to determine a compensation control signal according to the driving pulse - width correction signal.

[0063] The principle of the above - mentioned technical solution is as follows:

[0064] The present invention proposes to use an MCU as the control chip and an independent programming method, in cooperation with the corresponding peripheral acquisition circuit, to replace the driving control circuit with a BUCK driving IC as the core, so as to improve the flexibility of the BUCK driving application design and not be limited by the inherent defects of the driving chip.

[0065] In the actual implementation process, the MOS drive module is used to receive the dimming control signal and generate the drive voltage for dimming control drive. The BUCK buck module uses the constant-current buck control method to output the LED output current for dimming control. The peak current acquisition module of the present invention will collect the LED output current, and the collected current is processed by the MCU to determine whether there is a dimming deviation. If there is a dimming deviation, the corresponding drive pulse width correction signal will be output, and then for the drive pulse width correction signal, the compensation signal is determined through the current compensation calculation module. That is: the constant-current control method adopted will output the current signal, which is converted into a voltage signal through the peak current acquisition module and transmitted to the MCU, and through the collected voltage signal, the MCU corrects the drive pulse width in real time.

[0066] The beneficial effects of the above technical solutions are as follows:

[0067] The DC-DC digital dimming power supply device introduced in the present invention changes the method of using a BUCK drive IC as a current control device in the existing solution, and instead selects to monitor the output current change through the MCU. The advantage of the above method is that it can realize the drive and constant-current control of the BUCK circuit through MCU programming without relying on the BUCK drive IC.

[0068] As an embodiment of the present invention: the peak current acquisition module includes:

[0069] A signal amplification circuit for receiving the equivalent voltage signal and converting it to a preset voltage range;

[0070] A comparator for comparing the LED output current with the desired current value and outputting a comparison signal; among them, the desired current value signal is sent by the MCU processor.

[0071] The principle of the above technical solution is as follows:

[0072] In the peak current acquisition module of the present invention, the signal amplification circuit is used for signal acquisition to determine whether the equivalent voltage signal corresponding to the LED output current is within the preset voltage range. The comparator is used to compare the LED output current with the desired current value to determine whether compensation is required.

[0073] As an embodiment of the present invention: the comparison signal, the comparison signal includes a first signal and a second signal;

[0074] Among them, when the comparison signal is the first signal, the LED output current is higher than the desired current value, and the comparator outputs a rising edge signal;

[0075] Among them, when the comparison signal is the second signal, the LED output current is lower than the desired current value, and the comparator outputs a falling edge signal.

[0076] The principle of the above technical solution is as follows:

[0077] In the specific implementation of the present invention, compensation display is performed through current signals, and the rising edge and falling edge signals can clearly display the specific compensation values.

[0078] As an embodiment of the present invention: The signal amplification circuit includes: the eleventh resistor R11, the tenth resistor R10, the ninth resistor R9, the eighth resistor R8, the seventh resistor R7, the sixth resistor R6, the fourth capacitor C4, the fifth capacitor C5, the fifth resistor R5, the third capacitor C3, and the signal amplifier ARI;

[0079] One end of the eleventh resistor R11 is used to collect the LED output current and is connected to the positive input terminal of the signal amplifier ARI through the seventh resistor R7;

[0080] The other end of the eleventh resistor R11 is connected to the negative input terminal of the signal amplifier ARI through the eighth resistor R8;

[0081] The eleventh resistor R11 is connected in parallel with the tenth resistor R10 and the ninth resistor R9;

[0082] The negative input terminal of the signal amplifier ARI is also grounded through the fourth capacitor C4, and the positive input terminal of the signal amplifier ARI is also grounded through the fifth capacitor C5;

[0083] The negative input terminal and the output terminal of the signal amplifier ARI are connected in parallel with the fifth resistor R5, and the negative input terminal and the output terminal are also connected in parallel with the series-connected third capacitor C3 and sixth resistor R6.

[0084] The principle of the above technical solution is as follows:

[0085] As Figure 2 shown, the current acquisition input terminal is CUR_FEEDBACK (right end). After the current flows through this, it is converted into a voltage signal through the eleventh resistor R11, the tenth resistor R10, and the ninth resistor R9. Since the output current of the LED power supply is generally in mA, after flowing through three Ω-level sampling resistors, the converted equivalent voltage is in mV. Therefore, signal amplification processing is required. The operational amplifier AR1 is used to amplify the collected current signal to a voltage range that is easier for the single-chip microcomputer to recognize. Therefore, an amplification factor of 11 times is adopted. The amplified signal enters the negative terminal of the comparator.

[0086] As an embodiment of the present invention: The PA2 terminal of the comparator U1 is electrically connected to the output terminal of the signal amplification circuit through the fourth resistor R4. The PA0 terminal of the comparator U1 is electrically connected to the MCU processor through a two-stage RC filter circuit and receives the PWM wave emitted by the MCU processor, where the PWM wave is equivalent to the desired current value.

[0087] The output terminal of the comparator U1 is electrically connected to the MCU processor and is used to output a driving pulse width correction signal.

[0088] The principle of the above technical solution is as follows:

[0089] In the present invention, the positive terminal of the comparator U1 is connected to the PWM wave (PWM2) emitted by the MCU and equivalent to the desired current value.

[0090] As an embodiment of the present invention: The two-stage RC filter circuit includes: a series of first resistor R1, second resistor R2, and third resistor R3. Among them, the second resistor R2 is in parallel with a series of twelfth resistor R12 and first capacitor R1; a second capacitor C2 grounded is connected between the third resistor R3 and the PA0 port of the comparator U1.

[0091] The principle of the above technical solution is as follows:

[0092] In the present invention, after the PWM2 signal passes through the two-stage RC filter circuit, the PWM wave is converted into a DC signal, and this DC signal is equivalent to the voltage signal converted from the desired current value and is connected to the positive terminal of the comparator. The comparator will generate a rising edge or falling edge signal at the output terminal by comparing the magnitudes of the feedback current and the desired current.

[0093] In the specific implementation process:

[0094] If the actually feedback current value exceeds the desired output current value, the output result of the comparator changes from low level to high level, generating a rising edge signal. On the contrary, if the actual current value is lower than the desired output current value, the output result of the comparator will change from high level to low level, generating a falling edge signal. After receiving the rising edge and falling edge signals, the single-chip microcomputer can perform corresponding opening or closing operations on the output drive.

[0095] If it is detected that the output current at the current moment is higher than the desired current, after the comparator generates a rising edge signal and the single-chip microcomputer detects the rising edge, the drive signal will be closed in advance and restored in the next cycle to reduce the current and achieve the purpose of keeping the feedback current always within a small error range band of the desired current and achieving a constant current.

[0096] As an embodiment of the present invention: passing the LED output current through the MCU processor further includes:

[0097] Based on the LED output current interruption, generating a peak-shaped current distribution curve, and extracting the signal timing and amplitude characteristics of each peak and each valley through the peak-valley algorithm;

[0098] According to the peak-shaped current distribution curve, performing LED current signal conversion, and performing VMD decomposition after conversion to determine the dispersion entropy values of each peak and each valley;

[0099] Inputting the dispersion entropy value and the signal timing into the first PAC model to determine whether the LED output current corresponding to the signal timing needs to be compensated;

[0100] Wherein, when the LED output current corresponding to the signal timing needs to be compensated, inputting the dispersion entropy value and the amplitude characteristics into the second PAC model to determine the correction value of the LED output current demand corresponding to the signal timing.

[0101] The principle of the above technical solution is as follows:

[0102] The present invention includes four steps. First is the generation of the peak-shaped current distribution curve: The LED output current is monitored by the MCU processor, and a series of peak-shaped current distributions will be generated when the LED output current occurs. These peak-shaped currents are caused by the operation of the LED dimming control signal during the voltage control process, and each peak and valley represents a current pulse.

[0103] Then, there is the peak-valley algorithm. Through the peak-valley algorithm, the signal timing (i.e., the time points when the peaks and valleys appear) and amplitude characteristics (i.e., the magnitudes of the peaks and valleys) of each peak and valley can be extracted.

[0104] Subsequently, LED current signal conversion and VMD decomposition. The peak-shaped current distribution curve is converted into a format suitable for analysis, and then the variational mode decomposition (VMD) technique is used to decompose the current signal. VMD can decompose the complex current signal into multiple intrinsic mode functions (IMFs), and each IMF represents the current fluctuations of different frequency components. Through VMD decomposition, the dispersion entropy values of each peak and valley are determined, which reflects the complexity and randomness of the current signal.

[0105] Finally, there is the PAC model judgment: The first PAC model is used to determine whether the LED output current corresponding to the signal timing needs to be compensated. The PAC model is based on the theory of probabilistic approximate correctness and can determine with high probability whether the model is accurate. If the first PAC model determines that compensation is required, then the second PAC model is used to determine the specific correction value. The second PAC model takes into account the dispersion entropy value and the amplitude characteristics to more accurately estimate the required correction value.

[0106] In the specific implementation process:

[0107] The MCU processor monitors the LED output current in real time, records the current data when detecting output current interruption, and generates a peak-shaped current distribution curve: when the LED output current is interrupted, a peak-shaped current distribution curve is generated. For example, a spike may be generated in the current waveform each time the LED is switched on or off. Using the peak-valley algorithm, 10 spikes and the corresponding valleys are extracted, and their occurrence times and current amplitudes are recorded. The current signal is converted into a format suitable for VMD processing and decomposed to obtain 5 IMFs. Each IMF is analyzed, and the dispersion entropy value is extracted. For example, the dispersion entropy value of the first IMF is 0.8. The signal timing and the dispersion entropy value are input into the first PAC model, and the model determines that the current of the third spike needs to be compensated. The dispersion entropy value and amplitude characteristics of the third spike are input into the second PAC model, and the model outputs a correction value of +50 mA. The LED drive current is adjusted according to the correction value to compensate for the detected current fluctuations and ensure the stability of the brightness and dimming effect of the LED strip.

[0108] As an embodiment of the present invention: judging whether the LED output current corresponding to the signal timing needs to be compensated includes the following steps:

[0109] Input the dispersion entropy value into the first PAC model according to the signal timing to determine the nature characteristics of the LED current at each signal timing;

[0110] Based on the signal timing, calculate the fluctuation data of the LED current at different signal timings;

[0111] According to the fluctuation data and the expected current value, judge the long-range correlation of the LED current;

[0112] Among them, when the LED current belongs to the expected negative correlation, it means that the LED output current needs to be corrected;

[0113] Among them, when the LED current belongs to the expected positive correlation, it means that the LED output current does not need to be corrected;

[0114] Among them, when the LED current has no expected correlation, it means that the MOS drive module has a driving fault.

[0115] The principle of the above technical solution is as follows:

[0116] In the process of the present invention determining whether compensation is required by inputting the dispersion entropy value into the first PAC model, the dispersion entropy value is a quantitative index of signal complexity and randomness. The dispersion entropy value is input into the first PAC model according to the signal time series, and the model will analyze the characteristics of the LED current nature at each signal time series, such as stability, volatility, etc. Calculate the LED current fluctuation data, which is based on the signal time series and calculates the fluctuation data of the LED current at different time series. This involves analyzing the change amplitude and frequency of the current signal to understand the stability of the current. Judge the long-range correlation of the LED current, and the long-range correlation refers to the correlation of the signal at different time scales. By comparing the fluctuation data and the expected current value, the long-range correlation of the LED current can be judged. Expected negative correlation, which means that if the change of the LED current is negatively correlated with the expected current value, that is, the current fluctuation causes the brightness to be lower than the expected value, then correction is required. Expected positive correlation, which means that if the change of the LED current is positively correlated with the expected current value, that is, the current fluctuation does not affect the brightness stability, then correction is not required. No expected correlation, which means that if there is no correlation between the LED current and the expected current value, it may indicate a driving failure in the MOS driving module.

[0117] In the specific implementation process:

[0118] Step 1: The MCU processor collects the LED output current data and calculates the dispersion entropy values at 10 different signal time series points.

[0119] Step 2: Input these 10 dispersion entropy values into the first PAC model according to the signal time series, and the model analyzes the current nature characteristics at each time series point.

[0120] Step 3: Based on the signal time series, calculate the current fluctuation data at each time series point. For example, the current fluctuation at the fifth time series point is ±20 mA.

[0121] Step 4: Compare the fluctuation data with the expected current value (assumed to be 500 mA), and it is found that the current fluctuation at the fifth time series point causes the actual current to be lower than 500 mA, showing a negative correlation.

[0122] The current fluctuation at the third time series point is positively correlated with the expected current value, and the fluctuation does not affect the brightness stability.

[0123] The current fluctuation at the eighth time series point has no correlation with the expected current value, which may indicate a failure in the MOS driving module.

[0124] Step 5: For the fifth time series point, since the LED current belongs to the expected negative correlation, it is judged that the LED output current needs to be corrected. The correction value may be +20 mA to compensate for the fluctuation.

[0125] For the third time series point, since the LED current belongs to the expected positive correlation, no correction is required.

[0126] For the eighth timing point, since there is no expected correlation in the LED current, the system issues a warning indicating to check the MOS drive module.

[0127] As an embodiment of the present invention: determining whether the LED output current corresponding to the signal timing needs to be compensated further includes:

[0128] Input the LED output current and the scatter entropy value at each moment into the second PAC model to determine the compensation interval of the LED output current at each moment;

[0129] Determine the adjustable curve of the LED output current according to the compensation interval;

[0130] Determine whether there is a deviation value beyond the compensation interval when compensating the LED output current to the desired current value according to the adjustable curve and the desired current value;

[0131] Wherein, when there is a deviation value, determine the moment when the deviation value appears, and determine whether the drive current of the MOS drive module is abnormal. When the drive current of the MOS drive module is abnormal, control the MOS drive module to reset;

[0132] Wherein, when there is no deviation value, determine the correction value corresponding to each moment.

[0133] The principle of the above technical solution is as follows:

[0134] In the process of the present invention judging the current demand compensation value through the second PAC model,

[0135] First, input the LED output current and the scatter entropy value at each moment into the second PAC model. The model will analyze these data to determine the possible compensation interval of the LED output current at each moment. The compensation interval refers to the range within which the current can be adjusted without affecting the performance and lifespan of the LED.

[0136] Then, according to the compensation interval, draw the adjustable curve of the LED output current. This curve represents the limit within which the LED output current can be adjusted within the compensation interval.

[0137] Subsequently, compare the adjustable curve with the desired current value to determine whether there is a deviation value beyond the compensation interval. The deviation value refers to the difference between the actual current value and the desired current value, and this difference exceeds the compensation interval defined by the adjustable curve.

[0138] Among them, if there is a deviation value, the system will determine the moment when the deviation value appears and further check whether the drive current of the MOS drive module is abnormal. If it is detected that the drive current of the MOS drive module is abnormal, the system will control the MOS drive module to reset to eliminate the abnormal state.

[0139] Among them, if there is no ambiguous value, the system will determine the correction value corresponding to each moment according to the adjustable curve to adjust the LED output current so that it conforms to the desired current value.

[0140] As an embodiment of the present invention: the determining the compensation control signal includes:

[0141] Preset a desired equivalent network;

[0142] Input the driving pulse width correction signal into the desired equivalent network for equivalent calculation to determine the capacitance and inductance parameter values at each moment;

[0143] Perform fitting calculation on the capacitance and inductance parameter values at each moment and the preset constant current compensation conditions to determine the fitting value corresponding to the fitting calculation;

[0144] Convert the fitting value into a compensation control signal to compensate the dimming control signal.

[0145] The principle of the above technical solution is as follows: The method for determining the compensation control signal is further supplemented, which includes presetting a desired equivalent network, determining the capacitance and inductance parameter values at each moment through equivalent calculation of the driving pulse width correction signal, and performing fitting calculation on these values and the preset constant current compensation conditions to determine the corresponding fitting value. Then convert this fitting value into a compensation control signal and compensate the dimming control signal. This can not only make the current compensation more accurate, but also ensure the real-time performance and accuracy of the compensation control, and further improve the performance and reliability of the system.

[0146] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. A constant current detection control circuit for a DC-DC LED dimming power supply, characterized in that: include: MOS driver module; Used to receive dimming control signals and generate driving voltages; BUCK step-down module; Used to step down the driving voltage to generate LED output current; Peak current acquisition module: used to transmit the LED output current to the MCU processor to determine the drive pulse width correction signal; The step of transmitting the LED output current to the MCU processor further includes: Based on the LED output interruption, a peak current distribution curve is generated, and the signal timing and amplitude characteristics of each peak and each valley are extracted through the peak-valley algorithm; wherein the peak and valley are the current pulses corresponding to the spikes in the peak current distribution curve at each switch; According to the peak current distribution curve, the LED current signal is converted, and VMD decomposition is performed after the conversion to determine the distribution entropy value of each peak value and each valley value; Inputting the spread entropy value and the signal timing into the first PAC model to determine whether the LED output current corresponding to the signal timing needs to be compensated; When the LED output current corresponding to the signal timing needs to be compensated, the spread entropy value and the amplitude characteristic are input into the second PAC model to determine the required correction value of the LED output current corresponding to the signal timing; Current compensation calculation module: used to determine the compensation control signal according to the drive pulse width correction signal.

2. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 1, characterized in that: The peak current acquisition module comprises: A signal amplifying circuit, used for receiving an equivalent voltage signal and converting it into a preset voltage range; The comparator U1 is used to compare the LED output current with the expected current value and output a comparison signal; wherein the expected current value signal is sent by the MCU processor.

3. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 2, characterized in that: The comparison signal includes a first signal and a second signal; Wherein, when the comparison signal is the first signal, the LED output current is higher than the expected current value, and the comparator outputs a rising edge signal; When the comparison signal is the second signal, the LED output current is lower than the expected current value, and the comparator outputs a falling edge signal.

4. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 2, characterized in that: The signal amplifying circuit includes: an eleventh resistor R11, a tenth resistor R10, a ninth resistor R9, an eighth resistor R8, a seventh resistor R7, a sixth resistor R6, a fourth capacitor C4, a fifth capacitor C5, a fifth resistor R5, a third capacitor C3 and a signal amplifier ARI; One end of the eleventh resistor R11 is used to collect the LED output current, and is connected to the positive input end of the signal amplifier ARI through the seventh resistor R7; The other end of the eleventh resistor R11 is connected to the negative input end of the signal amplifier ARI through the eighth resistor R8; The eleventh resistor R11 is connected in parallel with the tenth resistor R10 and the ninth resistor R9; The negative input terminal of the signal amplifier ARI is also grounded via a fourth capacitor C4, and the positive input terminal of the signal amplifier ARI is also grounded via a fifth capacitor C5; A fifth resistor R5 is connected in parallel between the negative input terminal and the output terminal of the signal amplifier ARI, and a third capacitor C3 and a sixth resistor R6 connected in series are also connected in parallel between the negative input terminal and the output terminal.

5. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 2, characterized in that: The PA2 terminal of the comparator U1 is electrically connected to the output terminal of the signal amplification circuit through the fourth resistor R4, and the PA0 terminal of the comparator U1 is electrically connected to the MCU processor through the secondary RC filter circuit, and receives the PWM wave sent by the MCU processor, wherein the PWM wave is equivalent to the expected current value; The output end of the comparator U1 is electrically connected to the MCU processor for outputting a driving pulse width correction signal.

6. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 5, characterized in that: The secondary RC filter circuit includes: a first resistor R1, a second resistor R2 and a third resistor R3 connected in series, wherein the second resistor R2 is connected in parallel with a twelfth resistor R12 and a first capacitor R1 connected in series; a grounded second capacitor C2 is connected between the third resistor R3 and the PA0 port of the comparator U1.

7. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 1, characterized in that: The step of judging whether the LED output current corresponding to the signal timing needs to be compensated comprises the following steps: Inputting the spread entropy value into the first PAC model according to the signal timing sequence to determine the property characteristics of the LED current of each signal timing sequence; Based on the signal timing, calculate the fluctuation data of LED current at different signal timings; Determine the long-range correlation of LED current based on fluctuation data and expected current value; Among them, when the LED current belongs to the expected negative correlation, it means that the LED output current needs to be corrected; Among them, when the LED current belongs to the expected positive correlation, it means that the LED output current does not need to be corrected; Among them, when the LED current has no expected correlation, it means that the MOS driver module is driving fault.

8. A constant current detection control circuit for a DC-DC LED dimming power supply as claimed in claim 7, characterized in that: The step of determining whether the LED output current corresponding to the signal timing needs to be compensated further includes: Inputting the LED output current and the spread entropy value at each moment into the second PAC model to determine the compensation interval of the LED output current at each moment; According to the compensation interval, determine the adjustable curve of LED output current; According to the adjustable curve and the expected current value, determine whether the LED output current compensation is an expected current value that exceeds the compensation interval; Wherein, when there is an ambiguous value, the time when the ambiguous value occurs is determined, and whether the driving current of the MOS driving module is abnormal is determined, and when the driving current of the MOS driving module is abnormal, the MOS driving module is controlled to reset; When there is no ambiguity, the correction value corresponding to each moment is determined.

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