A pulse width modulation control method, circuit, system

Abstract

This disclosure provides a control method, circuit, and system for driving an LED channel. The method includes: selecting different transformed carriers for a pulse width modulation (PWM) control signal of a target channel within multiple carrier cycles, based on multiple transformed carriers with different phases; and modulating the rising and falling edges of the PWM control signal according to the duty cycle. This disclosure, for the same target channel, disperses noise energy from different cycles across a wider frequency band, thereby reducing electromagnetic interference spikes and improving electromagnetic interference performance.

Description

Technical Field

[0001] This disclosure relates to the field of LED technology, and in particular to a pulse width modulation control method, circuit, and system. Background Technology

[0002] With the development of technology and the popularization of smart devices, LEDs are becoming increasingly important in applications such as breathing lights in smart speakers, ambient lighting in cars, and light signal displays. LEDs are typically driven using a constant current source based on pulse width modulation (PWM) control signals to achieve effects such as breathing, dimming, and color mixing.

[0003] LED brightness can be controlled by controlling the average current level through the duty cycle of the pulse width modulation control signal. However, this method is not flexible enough, and large fluctuations in the system power supply can also lead to high levels of electromagnetic interference (EMI), affecting the application. Summary of the Invention

[0004] In view of this, one of the technical problems solved by the embodiments of this disclosure is to provide a pulse width modulation control method, circuit, and system, which at least partially solves the above-mentioned defects.

[0005] In a first aspect, embodiments of this disclosure provide a pulse width modulation control method for driving an LED channel. The method includes: selecting different transformed carriers for a pulse width modulation control signal of a target channel within multiple carrier cycles based on multiple transformed carriers with different phases; and modulating the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0006] Secondly, embodiments of this disclosure provide a pulse width modulation control method for driving LED channels. The method includes: selecting different transformation carriers for pulse width modulation control signals of multiple target channels within the same carrier period based on multiple transformation carriers with different phases; and modulating the rising and falling edges of the pulse width modulation control signals according to the duty cycle.

[0007] Thirdly, embodiments of this disclosure provide a pulse width modulation control circuit for driving an LED channel. The control circuit includes: a first carrier selection circuit for selecting different transformed carriers for a target channel's pulse width modulation control signal within multiple carrier cycles based on multiple transformed carriers with different phases; and a duty cycle modulation circuit for modulating the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0008] Fourthly, embodiments of this disclosure provide a pulse width modulation control circuit for driving LED channels. The control circuit includes: a second carrier selection circuit for selecting different transformed carriers for pulse width modulation control signals of multiple target channels within the same carrier period based on multiple transformed carriers with different phases; and a duty cycle modulation circuit for modulating the rising and falling edges of the pulse width modulation control signals according to the duty cycle.

[0009] Fifthly, embodiments of this disclosure provide an LED system, including a pulse width modulation control circuit as described in any of the third or fourth aspects, and an LED lamp driven and controlled by the control circuit.

[0010] This disclosure discloses a control scheme for driving LED channels, selecting different carrier waves for the pulse width modulation control signal of one target channel, or selecting different carrier waves for the pulse width modulation control signals of multiple target channels. For the same target channel, this disclosure distributes the noise energy of multiple carrier cycles across a wider frequency band, thereby reducing electromagnetic interference spikes and improving electromagnetic interference performance. For multiple target channels, this disclosure avoids the noise generated by multiple target channels from superimposing in time, forming stronger electromagnetic interference spikes; the switching noise of each target channel is dispersed in time, reducing electromagnetic interference. Attached Figure Description

[0011] The following sections will describe some specific embodiments of the present disclosure in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic diagram of a typical control circuit for driving an LED channel; Figure 2 A schematic diagram illustrating power supply voltage fluctuations caused by edge alignment of multi-channel pulse width modulation control signals; Figure 3 This is a flowchart of a control method for driving an LED channel according to an embodiment of the present disclosure; Figure 4 This is a timing diagram illustrating the comparison between the target channel pulse width modulation control signal and the normal pulse width modulation control signal in another embodiment of this disclosure. Figure 5 A schematic diagram showing the result of performing a fast Fourier transform on the pulse width modulation control signals PWM0 and PWM1; Figure 6 This is a flowchart of a control method for driving an LED channel in another embodiment of the present disclosure; Figure 7This is a schematic diagram illustrating the principle of generating a transformed carrier and producing a corresponding pulse width modulation control signal based on the original carrier in another embodiment of the present disclosure; Figure 8 This is a timing diagram of multiple target channel pulse width modulation control signals in another embodiment of the present disclosure; Figure 9 This is a flowchart of a control method for driving an LED channel in another embodiment of the present disclosure; Figure 10 This is a schematic diagram of a multi-channel pulse width modulation control circuit in another embodiment of the present disclosure; Figure 11 This is a schematic diagram of a multi-channel pulse width modulation control circuit in another embodiment of the present disclosure. Detailed Implementation

[0012] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art should fall within the protection scope of the present invention.

[0013] The technical terms used in the embodiments of this disclosure will be explained below.

[0014] PWM (Pulse Width Modulation) is a technique that regulates output power by controlling pulse signals. In LED control, the PWM signal determines the average brightness of the LED.

[0015] Electromagnetic interference (EMI): The rapid switching of pulse width modulation control signals may generate electromagnetic interference, requiring filtering and shielding measures.

[0016] Power management: Ensure that the power supply for the pulse width modulation control signal can provide sufficient current while maintaining a stable voltage.

[0017] See Figure 1 Typically, LED control circuits include: The pulse width modulation control circuit 12 is used to output multiple pulse width modulation control signals.

[0018] The switching circuit 13 is used to control the lighting effect of multiple LEDs according to multiple pulse width modulation control signals.

[0019] Specifically, the control circuit also includes a power supply module 11, which provides a power supply voltage to the pulse width modulation control circuit 12.

[0020] The pulse width modulation (PWM) control circuit 12 outputs multiple PWM control signals PWM1~PWMn, where n is a positive integer greater than or equal to 2. These signals control multiple switches K1~Kn in the switching circuit 13, where n is a positive integer greater than or equal to 2. This, in turn, controls the on / off state of multiple LEDs LED1~LEDn, where n is a positive integer greater than or equal to 2. When the PWM control signal PWMn is high, switch Kn is closed, and LEDn is lit. When the PWM control signal PWMn is low, switch Kn is open, and LEDn is off. Here, n is a natural number.

[0021] Specifically, the following functions can be achieved by periodically changing the duty cycle of multiple pulse width modulation control signals.

[0022] Brightness adjustment: The average brightness of the LED light is controlled by changing the duty cycle of the pulse width modulation control signal.

[0023] Flashing effect: The flashing effect of LED lights is achieved by periodically changing the duty cycle of the pulse width modulation control signal.

[0024] Dynamic effects: By adjusting the duty cycle of different pulse width modulation control signals, complex dynamic lighting effects can be achieved, such as breathing lights and gradient lights.

[0025] The current of the LED light (LEDn) is controlled by the pulse width modulation (PWMn) control signal, which cycles periodically and changes according to the desired lighting effect. In multi-channel applications, multiple channels of PWMn need to be output simultaneously, such as... Figure 2 As shown, if the pulse width modulation control signal PWMn of multiple channels changes in one direction at the same time, the maximum transient current of the pulse width modulation control circuit 12 will be large, resulting in strong fluctuations in the power supply voltage of the power supply module 11, which in turn leads to a deterioration in the EMI index.

[0026] Furthermore, in traditional PWM modulation, if the LED pulse width (duty cycle) remains constant and the phase scheme is fixed, the PWM phase output within two adjacent carrier cycles is also fixed. This fixed phase causes the current variation to exhibit a high degree of periodicity. Spectrally, this means that energy is concentrated at specific harmonic frequency points, resulting in severe electromagnetic interference spikes. Without cross-cycle randomization, a smooth noise spectrum spread cannot be achieved, making it difficult to effectively reduce EMI performance.

[0027] See Figure 3 This disclosure provides a control method for driving an LED channel, the method comprising: Step S1: Based on multiple transform carriers with different phases, select different transform carriers for the pulse width modulation control signal of a target channel within multiple carrier cycles.

[0028] Step S2: Modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0029] The embodiments of this disclosure distribute the noise energy of multiple carrier cycles over a wider frequency band for the same target channel, thereby reducing the peak value of electromagnetic interference and improving electromagnetic interference performance.

[0030] See Figure 4 For example, a comparison diagram of the pulse width modulation control signal PWM1 and the pulse width modulation control signal PWM0 of the target channel is shown. A schematic diagram illustrating how the pulse width modulation control signal PWM1 and the pulse width modulation control signal PWM0 improve electromagnetic interference is shown below. Figure 5 As shown. Figure 5 In this context, FFT_UNI is the result of performing a Fast Fourier Transform (FFT) on the pulse width modulation control signal PWM0. Figure 5 In the figure, FFT_RAN represents the result of performing a Fast Fourier Transform (FFT) on the pulse width modulation (PWM) control signal PWM1. The dominant frequency of the PWM0 control signal is 247.5 kHz, with a relatively high energy of -24 dB. The energy of the PWM1 control signal at its dominant frequency is dispersed; at the same frequency, the energy is -39 dB, indicating that the energy is concentrated near the dominant frequency. This reduction in the energy of the PWM1 control signal at its dominant frequency improves its electromagnetic interference performance.

[0031] Specifically, the multiple carrier cycles in this embodiment include at least two carrier cycles. If multiple carrier cycles exist, selecting different transformed carriers for at least two of the multiple carrier cycles can reduce the energy at the main frequency and improve electromagnetic interference performance. If each of the multiple carrier cycles selects a different transformed carrier, further reduction of the energy at the main frequency and improvement of electromagnetic interference performance can be achieved.

[0032] Specifically, in this embodiment, the multiple phase-differentiated carriers include at least two phase-differentiated carriers. The number of carriers can be the same as the number of carrier periods in the target channel, thereby selecting different carriers for each carrier period. Alternatively, the number of carriers can be less than the number of carrier periods in the target channel, ensuring that only a portion of the multiple carrier periods are selected with different carriers. For example, different carriers can be selected for five adjacent carrier periods. This reduces the complexity of carrier modulation and meets the needs of various application scenarios. When the number of carrier periods is greater than the number of carriers, the carrier periods can be grouped according to the number of carriers. For example, if the number of carriers is N, N consecutive carrier periods can be grouped together, with each carrier period in each group having a different phase of the corresponding carrier. That is, the number of carrier periods can be an integer multiple of the number of carriers, or it can be a non-integer multiple. In this case, the number of carrier periods in the last group is less than the number of carriers. Furthermore, the last period in the first group of two adjacent groups of carrier periods and the first period in the second group of carrier periods can be set to have different phases.

[0033] In some specific implementations of the embodiments disclosed herein, see [link to relevant documentation]. Figure 6 The method also includes: Step S3: Based on multiple transform carriers with different phases, select different transform carriers for the pulse width modulation control signals of multiple target channels within the same carrier period.

[0034] The embodiments disclosed herein avoid the noise generated by multiple target channels from superimposing on each other in time, forming a stronger electromagnetic interference spike. The switching noise of multiple target channels is dispersed in time, reducing electromagnetic interference.

[0035] In some specific implementations of the embodiments of this disclosure, the carrier transformation is selected based on a random number sequence or a pseudo-random number sequence.

[0036] Pseudo-random number sequences enable smoother noise spectrum spreading and effectively reduce spectrum concentration. This pseudo-randomization process evenly distributes noise energy from different periods across a wider frequency band, significantly reducing electromagnetic interference (EMI) spikes. In this way, the system not only reduces the periodicity of individual LEDs within adjacent periods but also disrupts the synchronicity of current changes among multi-target channel LEDs, resulting in smoother current fluctuations in both time and space, effectively improving the system's electromagnetic compatibility performance.

[0037] Specifically, embodiments of this disclosure utilize linear feedback shift registers to generate pseudo-random number sequences. Sequences generated using linear feedback shift registers exhibit uniform distribution over long periods, providing a low-cost and easily implemented digital randomization scheme in circuit design, replacing those complex or limited-effective fixed-delay schemes.

[0038] In some specific implementations of the embodiments of this disclosure, the generation of multiple transform carriers with different phases includes: Using different positions of the original carrier counting period as reference points, the count values ​​of the original carrier are processed to generate multiple transformed carriers with different phases.

[0039] The original carrier count is incremented from 0 to 2m-1 within the carrier period, where m is an integer greater than 3.

[0040] Multiple transformed carriers with different phases can be pre-stored or generated as needed based on the original carriers.

[0041] Specifically, the number of carrier waves corresponds to the number of pulse width control signals, thereby ensuring that different pulse width control signals are assigned to different carrier waves as much as possible. This further avoids the synchronization of current changes between multiple LED channels, making the current fluctuations smoother in both time and space, and effectively improving the electromagnetic compatibility performance of the system.

[0042] For example, see Figure 7 The original carrier CAR0 generates multiple transformed carriers CAR1~CARn with different phases, where n is an integer greater than 2.

[0043] The original carrier count increments from 0 to 2m-1 within the carrier period, where m is an integer greater than 3. Figure 7 Taking m=8 as an example, the counting range is 0~2m-1 (i.e., 255), with a total of 256 points, which is the resolution of an 8-bit pulse width control signal.

[0044] Using the position at 1 / 2 of the original carrier counting period as the reference point, the values ​​in the complete counting period are split into odd and even segments to obtain a symmetrical waveform consisting of a monotonically decreasing segment and a monotonically increasing segment. The monotonically decreasing segment and the monotonically increasing segment are mirror symmetrical with respect to the reference point, and the count value of the symmetrical waveform reaches a minimum value at the reference point, thus obtaining the transformed carrier CAR1.

[0045] Using the 1 / 4 mark of the original carrier counting period as a reference point, the first half of the original carrier counting period is divided into odd and even values ​​on both sides, resulting in a symmetrical waveform composed of a monotonically decreasing segment and a monotonically increasing segment, both using the 1 / 4 mark of the original carrier counting period as a reference point. The monotonically decreasing and increasing segments are mirror images of the 1 / 4 mark of the original carrier counting period, and the count value of the symmetrical waveform reaches a minimum at the 1 / 4 mark of the original carrier counting period. Using the 1 / 4 mark of the original carrier counting period as a reference point, the second half of the original carrier counting period is kept consistent with the original carrier. The first and second halves are then combined to obtain the transformed carrier CAR2.

[0046] Using the 1 / 8 mark of the original carrier counting period as a reference point, the first half of the original carrier counting period is divided into odd and even values ​​on both sides, resulting in a symmetrical waveform composed of a monotonically decreasing segment and a monotonically increasing segment, both using the 1 / 8 mark of the original carrier counting period as the reference point. The monotonically decreasing and increasing segments are mirror images of the 1 / 8 mark of the original carrier counting period, and the count value of the symmetrical waveform reaches a minimum at the 1 / 8 mark of the original carrier counting period. Using the 1 / 8 mark of the original carrier counting period as a reference point, the second half of the original carrier counting period is kept consistent with the original carrier. The first and second halves are then combined to obtain the transformed carrier CAR3.

[0047] Using the 3 / 4 mark of the original carrier counting period as a reference point, the values ​​in the latter half of the original carrier counting period are processed by dividing the data into odd and even values ​​on both sides, resulting in a symmetrical waveform composed of a monotonically decreasing segment and a monotonically increasing segment, both using the 3 / 4 mark of the original carrier counting period as a reference point. The monotonically decreasing and increasing segments are mirror images of the 3 / 4 mark of the original carrier counting period, and the count value of the symmetrical waveform reaches a minimum at the 3 / 4 mark of the original carrier counting period. Using the 3 / 4 mark of the original carrier counting period as a reference point, the first half of the original carrier counting period is reversed. The reversed first half is then combined with the processed second half to obtain the transformed carrier CAR4.

[0048] Using the 7 / 8 mark of the original carrier counting period as a reference point, the values ​​of the latter half of the original carrier counting period are processed by dividing the data into odd and even values ​​on both sides, resulting in a symmetrical waveform composed of a monotonically decreasing segment and a monotonically increasing segment, both using the 7 / 8 mark of the original carrier counting period as the reference point. The monotonically decreasing and increasing segments are mirror images of the 7 / 8 mark of the original carrier counting period, and the count value of the symmetrical waveform reaches a minimum at the 7 / 8 mark of the original carrier counting period. Using the 7 / 8 mark of the original carrier counting period as a reference point, the first half of the original carrier counting period is reversed. The reversed first half is then combined with the processed second half to obtain the transformed carrier CAR5.

[0049] This disclosure embodiment modulates the original carrier to generate multiple transformed carriers with different phases for the pulse width modulation (PWM) control signal to select. This allows for the selection of different transformed carriers for the PWM control signal of the target channel within multiple carrier cycles, and / or the selection of different transformed carriers for the PWM control signals of multiple target channels within the same carrier cycle. Furthermore, this disclosure embodiment uniformly distributes the noise energy of a target channel across a wider frequency band in different cycles, thereby significantly reducing electromagnetic interference (EMI) spikes. This disclosure embodiment also reduces the periodicity of a single target channel within adjacent cycles, as well as the synchronicity of current changes among multiple target channels, resulting in smoother current fluctuations in both time and space, effectively improving the system's electromagnetic compatibility performance.

[0050] For example, see Figure 8 The first pulse width modulation control signal PWM1 selects a different carrier CAR1 in the first carrier period, a different carrier CAR2 in the second carrier period, and a different carrier CAR5 in the third carrier period, based on a pseudo-random number sequence generated by a random number generator. This allows for the selection of different carriers for the first pulse width modulation control signal PWM1 in different carrier periods. This selection, which changes continuously with the pseudo-random number sequence, achieves a smoother noise spectrum spread and reduces electromagnetic interference.

[0051] See Figure 8 Within the second carrier cycle, the first pulse width modulation control signal PWM1 to the fifth pulse width modulation control signal PWM5 correspond to the transform carriers CAR2, CAR4, CAR5, CAR3, and CAR1, respectively. That is, within the same carrier cycle, different transform carriers (CAR2, CAR4, CAR5, CAR3, and CAR1) are selected for the first pulse width modulation control signal PWM1 to the fifth pulse width modulation control signal PWM5 to control the different positions of the first pulse width modulation control signal PWM1 to the fifth pulse width modulation control signal PWM5.

[0052] Different LED lights have different carrier phases even within the same carrier cycle, such as... Figure 8 During the second carrier cycle, PWM1~PWM5 correspond to the carrier transformations CAR2, CAR4, CAR5, CAR3, and CAR1 respectively, which further reduces the synchronicity and spectral concentration of current changes, thereby reducing the electromagnetic interference generated.

[0053] This disclosure also provides a control method for driving LED channels; see [link to relevant documentation]. Figure 9 The method includes: Step S3: Based on multiple transformed carriers with different phases, select different transformed carriers for the pulse width modulation control signals of multiple target channels within the same carrier period.

[0054] Step S4: Modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0055] The embodiments disclosed herein avoid the noise generated by multiple target channels from superimposing on each other in time, forming a stronger electromagnetic interference spike. The switching noise of multiple target channels is dispersed in time, reducing electromagnetic interference.

[0056] The carrier wave is selected based on a random number sequence or a pseudo-random number sequence.

[0057] Pseudo-random number sequences enable smoother noise spectrum spreading and effectively reduce spectrum concentration. This pseudo-randomization process evenly distributes noise energy from different periods across a wider frequency band, significantly reducing electromagnetic interference (EMI) spikes. In this way, the system not only reduces the periodicity of individual LEDs within adjacent periods but also disrupts the synchronicity of current changes among multi-target channel LEDs, resulting in smoother current fluctuations in both time and space, effectively improving the system's electromagnetic compatibility performance.

[0058] Specifically, embodiments of this disclosure utilize linear feedback shift registers to generate pseudo-random number sequences. Sequences generated using linear feedback shift registers exhibit uniform distribution over long periods, providing a low-cost and easily implemented digital randomization scheme in circuit design, replacing those complex or limited-effective fixed-delay schemes.

[0059] In some specific implementations of the embodiments of this disclosure, the generation of multiple transform carriers with different phases includes: Using different positions of the original carrier counting period as reference points, the count values ​​of the original carrier are processed to generate multiple transformed carriers with different phases.

[0060] The original carrier count is incremented from 0 to 2m-1 within the carrier period, where m is an integer greater than 3.

[0061] Multiple transformed carriers with different phases can be pre-stored or generated as needed based on the original carriers.

[0062] Specifically, the number of carrier waves corresponds to the number of pulse width control signals, thereby ensuring that different pulse width control signals are assigned to different carrier waves as much as possible. This further avoids the synchronization of current changes between multiple LED channels, making the current fluctuations smoother in both time and space, and effectively improving the electromagnetic compatibility performance of the system.

[0063] In some specific implementations of the embodiments of this disclosure, multiple pulse width modulation control signals are used to drive and control direct-drive lamps and matrix LED lamp systems, which can effectively reduce electromagnetic interference.

[0064] For the methods described above, please refer to [link / reference]. Figure 10 This disclosure also provides a pulse width modulation control circuit for driving an LED channel. The control circuit 10 includes: The first carrier selection circuit 101 is used to select different transformed carriers for the pulse width modulation control signal of a target channel within multiple carrier cycles based on multiple transformed carriers with different phases.

[0065] Duty cycle modulation circuit 102 is used to modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0066] The embodiments of this disclosure distribute noise energy of different periods over a wider frequency band for the same target channel, thereby reducing the peak value of electromagnetic interference and improving electromagnetic interference performance.

[0067] For the methods described above, please refer to [link / reference]. Figure 11 This disclosure also provides a pulse width modulation control circuit 11 for driving an LED channel. The control circuit 11 includes: The second carrier selection circuit 103 is used to select different transformed carriers for the pulse width modulation control signals of multiple target channels within the same carrier period, based on multiple transformed carriers with different phases.

[0068] Duty cycle modulation circuit 102 is used to modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

[0069] The embodiments disclosed herein avoid the superposition of noise generated by different target channels over time, which would form a stronger electromagnetic interference spike. The switching noise of each target channel is dispersed over time, thereby reducing electromagnetic interference.

[0070] This disclosure also provides an LED system, including any of the above-described control circuits for driving LED channels and an LED lamp driven and controlled by the control circuit for the driven LED channel.

[0071] This disclosure embodiment, for the same target channel, disperses noise energy of different periods across a wider frequency band, thereby reducing the peak value of electromagnetic interference and improving electromagnetic interference performance. Alternatively, for multiple target channels, this disclosure embodiment avoids the noise generated by different target channels from superimposing in time to form stronger electromagnetic interference peaks; the switching noise of each target channel is dispersed in time, reducing electromagnetic interference.

[0072] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments disclosed herein.

[0073] This disclosure describes embodiments, but is not intended to limit them. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure. Therefore, all equivalent technical solutions also fall within the scope of this disclosure. The patent protection scope of this disclosure should be defined by the claims.

Claims

1. A pulse width modulation control method for driving an LED channel, characterized by, The method includes: Based on multiple transform carriers with different phases, different transform carriers are selected for the pulse width modulation control signal of a target channel within multiple carrier cycles; The rising and falling edges of the pulse width modulation control signal are modulated according to the duty cycle.

2. The control method according to claim 1, characterized by, The method further includes: Based on multiple transformed carriers with different phases, different transformed carriers are selected for the pulse width modulation control signals of multiple target channels within the same carrier period.

3. The control method according to claim 1 or 2, characterized by, The transformation carrier is selected based on a random number sequence or a pseudo-random number sequence.

4. The control method according to claim 1, characterized by, The generation of the multiple phase-differentiated transform carriers includes: Using different positions of the original carrier counting period as reference points, the counting values ​​of the original carrier are processed to generate multiple transformed carriers with different phases; The original carrier count is incremented from 0 to 2m-1 within the carrier period, where m is an integer greater than 3.

5. A pulse width modulation control method for driving an LED channel, characterized by, The method includes: Based on multiple transformed carriers with different phases, different transformed carriers are selected for the pulse width modulation control signals of multiple target channels within the same carrier period; The rising and falling edges of the pulse width modulation control signal are modulated according to the duty cycle.

6. The control method according to claim 5, characterized in that, The method further includes: Based on multiple transform carriers with different phases, different transform carriers are selected for the pulse width modulation control signal of a target channel within multiple carrier cycles.

7. The control method according to claim 5 or 6, characterized in that, The transformation carrier is selected based on a random number sequence or a pseudo-random number sequence.

8. The control method according to claim 5, characterized by, The generation of the multiple phase-differentiated transform carriers includes: Using different positions of the original carrier counting period as reference points, the counting values ​​of the original carrier are processed to generate multiple transformed carriers with different phases; The original carrier count is incremented from 0 to 2m-1 within the carrier period, where m is an integer greater than 3.

9. A pulse width modulation control circuit for driving an LED channel, the control circuit comprising: The first carrier selection circuit is used to select different transformed carriers for the pulse width modulation control signal of a target channel within multiple carrier cycles based on multiple transformed carriers with different phases. A duty cycle modulation circuit is used to modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

10. A pulse width modulation control circuit for driving an LED channel, the control circuit comprising: The second carrier selection circuit is used to select different transformed carriers for the pulse width modulation control signals of multiple target channels within the same carrier period, based on multiple transformed carriers with different phases. A duty cycle modulation circuit is used to modulate the rising and falling edges of the pulse width modulation control signal according to the duty cycle.

11. An LED system comprising the pulse width modulation control circuit of any one of claims 9 or 10 and an LED lamp driven and controlled by the control circuit.

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