Control circuit, method and system for driving LED channel

Abstract

The embodiment of the invention provides a control circuit, method and system for driving an LED channel. The control circuit comprises a power supply module, a pulse width modulation control circuit and a switching circuit. The falling edge sum of a first pulse width modulation control signal in the plurality of pulse width modulation control signals is a fixed position; the rising edge of a second pulse width modulation control signal in the plurality of pulse width modulation control signals is at a fixed position; the rising edge of the second pulse width modulation control signal is in front of the falling edge of the first pulse width modulation control signal, the requirement for the loading capacity of the pulse width modulation control circuit is lowered, transient current, power supply fluctuation and electromagnetic interference are effectively reduced, and the stability and electromagnetic compatibility of the system are improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of LED technology, and in particular, to a control circuit, method, and system for driving an LED channel. Background Art

[0002] With the development of technology and the popularization of smart devices, LEDs are particularly important in applications such as smart speaker breathing lights, car atmosphere lights, and light language displays. Usually, LEDs are driven using a constant current source based on PWM to achieve effects such as breathing, dimming, and color mixing.

[0003] The brightness control of LED can be achieved by controlling the average current level through the PWM duty cycle. However, the control scheme for driving LED channels usually has the defect of high power supply load requirements. At the same time, large fluctuations in system power supply will also lead to high EMI levels, affecting applications. Summary of the invention

[0004] In view of this, one of the technical problems solved by the embodiments of the present application is to provide a control circuit, method, and system for driving an LED channel, which at least partially solve the above-mentioned defects.

[0005] In a first aspect, an embodiment of the present application provides a control circuit for driving an LED channel, the control circuit comprising: a power supply module for providing a power supply voltage; a pulse width modulation control circuit for receiving the power supply voltage provided by the power supply module and outputting a plurality of pulse width modulation control signals; a switch circuit for opening or closing according to the levels of the plurality of pulse width modulation control signals to control the lighting effects of a plurality of LED lamps; the falling edge of a first pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameters of the first LED lamp, so as to control the lighting of the first LED lamp in a periodic cycle; the rising edge of a second pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameters of the second LED lamp, so as to control the lighting of the second LED lamp in a periodic cycle; the rising edge of the second pulse width modulation control signal is before the falling edge of the first pulse width modulation control signal.

[0006] In a second aspect, an embodiment of the present application provides a control method for driving an LED channel, the control method comprising: receiving a power supply voltage provided by the power supply module, and outputting a plurality of pulse width modulation control signals; opening or closing according to the levels of the plurality of pulse width modulation control signals, and controlling the lighting effects of a plurality of LED lamps; the falling edge of a first pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameters of the first LED lamp, so as to control the lighting of the first LED lamp in a periodic cycle; the rising edge of a second pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameters of the second LED lamp, so as to control the lighting of the second LED lamp in a periodic cycle; the rising edge of the second pulse width modulation control signal is before the falling edge of the first pulse width modulation control signal.

[0007] In a third aspect, an embodiment of the present application provides an LED system, comprising the control circuit for driving the LED channel according to the first aspect and an LED lamp driven and controlled by the control circuit for driving the LED channel.

[0008] In the scheme for driving the LED channel of the embodiment of the present application, the rising edge of the second pulse width modulation control signal is before the falling edge of the first pulse width modulation control signal, and the interval between the rising edge of the second pulse width modulation control signal and the falling edge of the first pulse width modulation control signal can be set according to the magnitude of the transient current of the pulse width modulation control circuit and the fluctuation effect of the power supply voltage of the power supply module. The embodiment of the present application reduces the requirements for the load capacity of the pulse width modulation control circuit, effectively reduces transient current, power supply fluctuation and electromagnetic interference, and improves the stability and electromagnetic compatibility of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Hereinafter, some specific embodiments of the present application will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0010] Figure 1 A schematic diagram of a control circuit for driving an LED channel according to an embodiment of the present application;

[0011] Figure 2 is a schematic diagram of a pulse width modulation control signal PWMn;

[0012] Figure 3 A schematic diagram of a pulse width modulation control signal PWMn according to an embodiment of the present application;

[0013] Figure 4A schematic diagram of another pulse width modulation control signal PWMn according to an embodiment of the present application;

[0014] Figure 5 A schematic diagram of a pulse width modulation control circuit in a control circuit for driving an LED channel according to an embodiment of the present application;

[0015] Figure 6 It is a schematic diagram of a pulse width modulation control circuit in a control circuit for driving an LED channel according to another embodiment of the present application;

[0016] Figure 7 This is a schematic diagram of a pulse width modulation control circuit in a control circuit for driving an LED channel according to yet another embodiment of the present application;

[0017] Figure 8 This is a schematic diagram of a pulse width modulation control circuit in a control circuit for driving an LED channel according to yet another embodiment of the present application;

[0018] Fig. 9 A schematic diagram of a third pulse width modulation control signal PWM3 according to an embodiment of the present application;

[0019] Fig.10 A schematic diagram of another third pulse width modulation control signal PWM3 according to an embodiment of the present application;

[0020] Fig.11 A schematic diagram of yet another third pulse width modulation control signal PWM3 according to an embodiment of the present application;

[0021] Fig.12 This is a flow chart of a control method for driving an LED channel according to an embodiment of the present application;

[0022] Fig.13 This is a flow chart of a control method for driving an LED channel according to another embodiment of the present application. DETAILED DESCRIPTION

[0023] In order 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 described clearly and in detail below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in the field based on the embodiments in the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0024] Reference is made to the accompanying drawings in the following detailed description, which form a part of the detailed description and illustrate exemplary embodiments. In addition, it is to be understood that other embodiments may be utilized and structural and / or logical changes may be made without departing from the scope of the claimed subject matter. It should also be noted that directions and references (e.g., up, down, top, bottom, etc.) may be used merely to facilitate the description of features in the accompanying drawings. Therefore, the following detailed description is not to be understood in a limiting sense, and the scope of the claimed subject matter is limited only by the appended claims and their equivalents.

[0025] In the following description, numerous details are set forth. However, it will be apparent to those skilled in the art that the embodiments herein can be practiced without these specific details. In some cases, known methods and devices are shown in block diagram form, rather than in detail, to avoid blurring the embodiments herein. References to "embodiment" or "one embodiment" or "some embodiments" throughout this specification mean that the specific features, structures, functions or characteristics described in conjunction with the embodiment are included in at least one embodiment herein. Therefore, the phrases "in an embodiment" or "in one embodiment" or "some embodiments" appearing throughout this specification do not necessarily refer to the same embodiment. In addition, in one or more embodiments, specific features, structures, functions or characteristics may be combined in any suitable manner. For example, the first embodiment may be combined with the second embodiment in any case where the specific features, structures, functions or characteristics associated with the two embodiments are not mutually exclusive.

[0026] As used in the description and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0027] The terms "coupled" and "connected" together with their derivatives may be used in this article to describe the functional or structural relationship between components. It should be understood that these terms are not intended to be synonymous with each other. On the contrary, in a particular embodiment, "connected" can be used to indicate that two or more elements are in direct physical, optical or electrical contact with each other. "Coupled" can be used to indicate that two or more elements are in direct or indirect (with other intermediate elements between them) physical or electrical contact with each other, and / or that two or more elements cooperate or interact with each other (e.g., as in a cause-and-effect relationship).

[0028] As used herein, the terms "above," "below," "between," and "on" refer to the relative position of one component or material with respect to other components or materials where such physical relationship is noteworthy. For example, in the context of materials, a material or materials disposed above or below another material may be in direct contact, or may have one or more intervening materials. Also, a material disposed between two materials or materials may be in direct contact with both layers, or may have one or more intervening layers. In contrast, a first material or material "above" a second material or material is in direct contact with the second material / materials. Similar distinctions are made in the context of component assembly.

[0029] As used throughout the description herein and in the claims, a list of items connected by the term "at least one of" or "one or more of" may mean any combination of the listed items. For example, the phrase "at least one of A, B, or C" may mean A; B; C; A and B; A and C; B and C; or A, B, and C.

[0030] The term "circuit" or "module" may refer to one or more passive and / or active components that are arranged to cooperate with each other to provide a desired functionality. The term "signal" may refer to at least one current signal, voltage signal, or magnetic signal. The terms "substantially," "close," "approximately," "close to," and "approximately" generally refer to within + / - 10% of a target value.

[0031] The technical terms used in the embodiments of the present application are first explained below.

[0032] PWM (Pulse Width Modulation): is a technique that adjusts the output power by controlling the duty cycle of a pulse signal. In LED control, the duty cycle of the PWM signal determines the average brightness of the LED.

[0033] Duty cycle: The ratio of high level time to total cycle time.

[0034] Brightness control: The larger the duty cycle, the higher the average current of the LED and the brighter the brightness; the smaller the duty cycle, the dimmer the brightness.

[0035] Electromagnetic compatibility (EMC): The fast switching of PWM signals may generate electromagnetic interference, requiring filtering and shielding measures.

[0036] Power management: Ensures that the power supply for the PWM signal can provide enough current while maintaining a stable voltage.

[0037] The present application embodiment provides a control circuit for driving an LED channel. Figure 1 , the control circuit comprises:

[0038] The power supply module 11 is used to provide a power supply voltage.

[0039] The pulse width modulation control circuit 12 is used to receive the power supply voltage provided by the power supply module 11 and output a plurality of pulse width modulation control signals.

[0040] The switch circuit 13 is used to open or close according to the levels of multiple pulse width modulation control signals to control the lighting effects of multiple LED lamps.

[0041] Specifically, the pulse width modulation control circuit 12 outputs a plurality of pulse width modulation control signals PWM1-PWMn (n=1, 2, 3, ...n) to control a plurality of switches K1-Kn (n=1, 2, 3, ...n) in the switch circuit 13, thereby controlling the on and off of a plurality of LED lamps LED1-LEDn (n=1, 2, 3, ...n). When the pulse width modulation control signal PWMn is at a high level, the switch Kn is closed, and the LED lamp LEDn is lit. When the pulse width modulation control signal PWMn is at a low level, the switch Kn is opened, and the LED lamp LEDn is extinguished. Wherein, n is a natural number.

[0042] The current of LED lamp LEDn is controlled by the average duty cycle of pulse width modulation control signal PWMn. The pulse width modulation control signal PWMn presents a periodic cycle, and the duty cycle changes according to the lighting effect. When multi-channel applications are used, it is necessary to output multi-channel pulse width modulation control signals PWMn at the same time, such as Figure 2 As shown, if the edges of the pulse width modulation control signals PWMn of multiple channels change in one direction at the same time, the maximum transient current of the pulse width modulation control circuit 12 will be relatively large, and the power supply load requirements of the pulse width modulation control circuit 12 will be relatively high. At the same time, the power supply voltage of the power supply module 11 will fluctuate strongly, thereby causing the EMI index to deteriorate.

[0043] In the embodiment of the present application, the falling edge of the first pulse width modulation control signal PWM1 among the multiple pulse width modulation control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameters of the first LED lamp LED1, so as to control the on and off of the first LED lamp LED1 in a periodic cycle.

[0044] Specifically, when the first pulse width modulation control signal PWM1 is at a high level, the switch K1 is closed, and the first LED lamp LED1 is lit; when the first pulse width modulation control signal PWM1 is at a low level, the switch K1 is opened, and the first LED lamp LED1 is extinguished. The extinguishing edge of the first LED lamp LED1 (the falling edge of the first pulse width modulation control signal PWM1) is a fixed position, and the lighting edge of the first LED lamp LED1 (the rising edge of the first pulse width modulation control signal PWM1) changes according to the duty cycle corresponding to the lighting effect parameter, so as to control the on and off of the first LED lamp LED1 in a periodic cycle.

[0045] Specifically, by periodically changing the duty cycle of PWM1, the following functions can be achieved.

[0046] Brightness adjustment: Control the average brightness of LED1 by changing the duty cycle.

[0047] Flashing effect: By periodically changing the duty cycle, the flashing effect of LED1 is achieved.

[0048] Dynamic effects: According to different lighting effect parameters, complex dynamic lighting effects can be achieved, such as breathing lights, gradient lights, etc.

[0049] In the embodiment of the present application, the rising edge of the second pulse width modulation control signal PWM2 among the multiple pulse width modulation control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameters of the second LED lamp LED2, so as to control the on and off of the second LED lamp LED2 in a periodic cycle.

[0050] Specifically, when the second pulse width modulation control signal PWM2 is at a high level, the switch K2 is closed and LED2 is lit; when the second pulse width modulation control signal PWM2 is at a low level, the switch K2 is opened and the second LED lamp LED2 is turned off. The lighting edge of the second LED lamp LED2 (the rising edge of the second pulse width modulation control signal PWM2) is a fixed position, and the lighting edge of the second LED lamp LED2 (the falling edge of the second pulse width modulation control signal PWM2) changes according to the duty cycle corresponding to the lighting effect parameter, so as to control the lighting of the second LED lamp LED2 in a periodic cycle.

[0051] In the embodiment of the present application, the rising edge of the second pulse width modulation control signal PWM2 is before the falling edge of the first pulse width modulation control signal PWM1, and the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1 can be set according to the size of the transient current of the pulse width modulation control circuit and the fluctuation effect of the power supply voltage VDD of the power supply module.

[0052] Specifically, see Figure 3 and Figure 4 , the embodiment of the present application optimizes the circuit performance by adjusting the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1. The smaller the value of the interval Td, the smaller the fluctuation of the power supply voltage VDD. At this node, the larger the transient current of the pulse width modulation control circuit, the higher the power supply load capacity required for the pulse width modulation control circuit, but the better the power supply voltage fluctuation offset effect of the power supply module 11. The embodiment of the present application meets the requirements of the size of the transient current of the pulse width modulation control circuit and the fluctuation effect of the power supply voltage VDD of the power supply module by setting the interval Td.

[0053] In some specific implementations of the embodiments of this application, see Figure 5 The pulse width modulation control circuit 12 includes: a first pulse width signal generating circuit 121, used to generate a first pulse width modulation control signal PWM1 according to a periodic first clock signal Clk1. A second pulse width signal generating circuit 122, used to generate a second pulse width modulation control signal PWM2 according to the periodic first clock signal Clk1.

[0054] The first pulse width signal generating circuit 121 includes: a pre-circuit 1211 for generating a pre-first pulse width modulation control signal PWM1_pre according to a first clock signal; and a delay sub-circuit 1212 for obtaining a first pulse width modulation control signal PWM1 according to the pre-first pulse width modulation control signal.

[0055] The interval between the rising edge of the second pulse width modulation control signal and the falling edge of the first pulse width modulation control signal is adjusted by the delay value of the delay subcircuit.

[0056] Specifically, see Figure 6 , the pre-amplifier sub-circuit 1211 comprises:

[0057] The first trigger DFF1 is configured to be triggered by the periodic first clock signal Clk1 to output a pre-set first pulse width modulation control signal PWM1_pre.

[0058] The delay subcircuit 1212 includes:

[0059] The first buffer Buffer1 is used for receiving the pre-placed first pulse width modulation control signal PWM1_pre, and obtaining the first pulse width modulation control signal PWM1 after delay.

[0060] The second pulse width signal generating circuit 122 comprises:

[0061] The second trigger DFF2 is configured to be triggered by the first clock signal Clk1 to output a second pulse width modulation control signal PWM2.

[0062] The interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1 is adjusted by the delay value of the first buffer Buffer1.

[0063] In the embodiment of the present application, precise control of the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1 is achieved through a specific circuit design. The synchronization of the pre-first pulse width modulation control signal PWM1_pre and the first clock signal Clk1 is ensured through the first trigger DFF1, providing a stable input signal for the subsequent first buffer Buffer1. The first buffer Buffer1 can improve the rising and falling edge characteristics of the signal, not only providing a flexible delay adjustment capability, but also improving the integrity of the signal and optimizing the timing.

[0064] In some other specific implementations of the embodiments of the present application, see Figure 7 , the pre-amplifier sub-circuit 1211 comprises:

[0065] The third flip-flop DFF3 is configured to be triggered by the periodic first clock signal Clk1 to output a pre-set first pulse width modulation control signal PWM1_pre.

[0066] The delay subcircuit 1212 includes:

[0067] The fourth trigger DFF4 is used for receiving the first pulse width modulation control signal PWM1_pre at the D terminal, and is triggered by the first clock signal Clk1 of the same source to delay the first pulse width modulation control signal PWM1_pre and output the first pulse width modulation control signal PWM1.

[0068] The second pulse width signal generating circuit 122 comprises:

[0069] The fifth flip-flop DFF5 is configured to be triggered by the first clock signal Clk1 to output a second pulse width modulation control signal PWM2.

[0070] An interval Td between a rising edge of the second PWM control signal PWM2 and a falling edge of the first PWM control signal PWM1 is determined by a propagation delay between the third flip-flop DFF3 and the fourth flip-flop DFF4 and a period of the first clock signal Clk1 .

[0071] The embodiment of the present application determines the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1 by the propagation delay between the third trigger DFF3 and the fourth trigger DFF4, and the period of the first clock signal Clk1. The circuit design of the embodiment of the present application can accurately control the interval between the two PWM signals, avoid overlap or conflict between the signals, and ensure the stability and consistency of the signals. The periodic triggering of the clock signal in the embodiment of the present application makes the generation of the PWM signal more accurate, and reduces false triggering caused by signal jitter or noise. The embodiment of the present application uses a simple circuit design to achieve the generation and control of the PWM signal, avoids complex circuit design, reduces the complexity of the circuit, and reduces hardware costs.

[0072] In some specific implementations of the embodiments of the present application, see Figure 8 , the pre-amplifier sub-circuit 1211 comprises:

[0073] The sixth flip-flop DFF6 is configured to be triggered by the periodic first clock signal and output a pre-set first pulse width modulation control signal.

[0074] The delay subcircuit 1212 includes:

[0075] The second buffer Buffer2 is used to receive the first clock signal and obtain the buffered first clock signal after delay.

[0076] The inverter INV is used for receiving the buffered first clock and obtaining the reverse buffered first clock signal after inversion.

[0077] The NAND logic circuit is used for receiving the reverse buffered first clock signal and performing a NAND logic operation on the first clock signal to obtain a second clock signal.

[0078] The seventh trigger DFF7 is used to receive the first pulse width modulation control signal at the D terminal and is triggered by the second clock signal to delay the first pulse width modulation control signal and output the first pulse width modulation control signal.

[0079] The second pulse width signal generating circuit 122 comprises:

[0080] The eighth trigger DFF8 is configured to be triggered by the first clock signal and output a second pulse width modulation control signal.

[0081] The interval between the rising edge of the second PWM control signal and the falling edge of the first PWM control signal is determined by the propagation delay between the sixth flip-flop DFF6 and the seventh flip-flop DFF7 and the delay of the second buffer Buffer2, the inverter INV, and the NAND logic circuit.

[0082] The embodiment of the present application can accurately control the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1 through the propagation delay between multiple delay elements (such as the second buffer Buffer2, the inverter INV, and the NAND logic circuit) and the trigger. This design can achieve high-precision time control and is suitable for application scenarios with strict timing requirements.

[0083] It is worth noting that the circuit for generating the interval Td between the rising edge of the second pulse width modulation control signal and the falling edge of the first pulse width modulation control signal in the embodiment of the present application is not limited to Figures 5 to 7 As shown, any circuit that can realize the generation of the interval Td is within the protection scope of this application.

[0084] In some further specific implementations of the embodiments of the present application, the center position of the third pulse width modulation control signal PWM3 among the multiple pulse width modulation control signals is at a fixed position within the pulse width modulation control period, and the rising edge and falling edge of the third pulse width modulation control signal PWM3 change according to the duty cycle corresponding to the lighting effect parameters of the third LED lamp, so as to control the lighting of the third LED lamp in a periodic cycle.

[0085] Specifically, when the third pulse width modulation control signal PWM3 is at a high level, the switch K3 is closed, and the third LED lamp LED3 is lit; when the third pulse width modulation control signal PWM3 is at a low level, the switch K3 is opened, and the third LED lamp LED3 is extinguished. The center position of the third pulse width modulation control signal PWM3 is at a fixed position within the pulse width modulation control cycle. The extinguishing edge of the third LED lamp LED3 (the falling edge of the third pulse width modulation control signal PWM3) and the lighting edge of the third LED lamp LED3 (the rising edge of the third pulse width modulation control signal PWM3) change according to the duty cycle corresponding to the lighting effect parameter, so as to control the on and off of the third LED lamp LED3 in a periodic cycle.

[0086] The embodiment of the present application achieves precise control and flexible adjustment of LED 3 by dynamically adjusting the positions of the rising edge and the falling edge of the third pulse width modulation control signal PWM3. At the same time, the embodiment of the present application also reduces the system power supply fluctuation caused by the third pulse width modulation control signal PWM3 and the problem of excessively high load requirements on the pulse width modulation control circuit by fixing the center position of the high level of the third pulse width modulation control signal PWM3.

[0087] Specifically, the center position of the third pulse width modulation control signal PWM3 is at a fixed position within the pulse width modulation control period, including the following situations:

[0088] The center position of the third pulse width modulation control signal PWM3 is fixed at the center position of the pulse width modulation control period, such as Fig. 9 shown.

[0089] The center position of the third pulse width modulation control signal PWM3 is fixed at the falling edge position of the first pulse width modulation control signal PWM1. Fig.10 shown.

[0090] The center position of the third pulse width modulation control signal PWM3 is fixed at the position of the rising edge of the second pulse width modulation control signal PWM2. Fig.11 shown.

[0091] It is worth noting that the fixed position of the center position of the third pulse width modulation control signal PWM3 in the pulse width modulation control period of the embodiment of the present application is not limited to Figures 9 to 11 As shown, any fixed position that can realize the center position of the third pulse width modulation control signal PWM3 within the pulse width modulation control period is within the protection scope of the present application.

[0092] Corresponding to the above circuit, the present application also provides a control method for driving an LED channel, see Fig.12 , the control method comprises:

[0093] Step S1: receiving a power supply voltage provided by a power supply module and outputting a plurality of pulse width modulation control signals.

[0094] Step S2: opening or closing the plurality of LED lamps according to the levels of the plurality of pulse width modulation control signals to control the lighting effects of the plurality of LED lamps.

[0095] Among them, the falling edge of the first PWM control signal among the multiple PWM control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameter of the first LED lamp, so as to control the on and off of the first LED lamp in a periodic cycle.

[0096] The rising edge of the second PWM control signal among the multiple PWM control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameter of the second LED lamp, so as to control the on and off of the second LED lamp in a periodic cycle.

[0097] The rising edge of the second PWM control signal is before the falling edge of the first PWM control signal.

[0098] The embodiment of the present application optimizes the circuit performance by adjusting the interval Td between the rising edge of the second pulse width modulation control signal PWM2 and the falling edge of the first pulse width modulation control signal PWM1. The smaller the value of the interval Td, the smaller the fluctuation of the power supply voltage VDD. At this node, the larger the transient current of the pulse width modulation control circuit, the higher the power supply load capacity required for the pulse width modulation control circuit, but the better the supply voltage fluctuation offset effect of the power supply module 11. The embodiment of the present application satisfies the requirements of the size of the transient current of the pulse width modulation control circuit and the fluctuation effect of the power supply voltage VDD of the power supply module by setting the interval Td.

[0099] In some specific implementations of the embodiments of this application, see Fig.13 , the method further comprises:

[0100] Step S3: The center position of the third PWM control signal among the multiple PWM control signals is at a fixed position within the PWM control period, and the rising edge and falling edge of the third PWM control signal change according to the duty cycle corresponding to the lighting effect parameters of the third LED lamp, so as to control the on and off of the third LED lamp in a periodic cycle.

[0101] The embodiment of the present application achieves precise control and flexible adjustment of LED 3 by dynamically adjusting the positions of the rising edge and the falling edge of the third pulse width modulation control signal PWM3. At the same time, the embodiment of the present application also reduces the system power supply fluctuation caused by the third pulse width modulation control signal PWM3 and the problem of excessively high load requirements on the pulse width modulation control circuit by fixing the center position of the high level of the third pulse width modulation control signal PWM3.

[0102] Specifically, the center position of the third pulse width modulation control signal PWM3 is at a fixed position within the pulse width modulation control period, including the following situations:

[0103] The center position of the third pulse width modulation control signal PWM3 is fixed at the center position of the pulse width modulation control period, such as Fig. 9 shown.

[0104] The center position of the third pulse width modulation control signal PWM3 is fixed at the falling edge position of the first pulse width modulation control signal PWM1. Fig.10 shown.

[0105] The center position of the third pulse width modulation control signal PWM3 is fixed at the position of the rising edge of the second pulse width modulation control signal PWM2. Fig.11 shown.

[0106] It is worth noting that the fixed position of the center position of the third pulse width modulation control signal PWM3 in the pulse width modulation control period of the embodiment of the present application is not limited to Figures 8 to 10As shown, any fixed position that can realize the center position of the third pulse width modulation control signal PWM3 within the pulse width modulation control period is within the protection scope of the present application.

[0107] The present application also provides an LED system, including any one of the above control circuits for driving LED channels and an LED lamp driven and controlled by any one of the above control circuits for driving LED channels.

[0108] The embodiment of the present application achieves precise control and flexible adjustment of LED 3 by dynamically adjusting the positions of the rising edge and the falling edge of the third pulse width modulation control signal PWM3. At the same time, the embodiment of the present application also reduces the system power supply fluctuation caused by the third pulse width modulation control signal PWM3 and the problem of excessively high load requirements on the pulse width modulation control circuit by fixing the center position of the high level of the third pulse width modulation control signal PWM3.

[0109] Those of ordinary skill in the art will appreciate that the units and method steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0110] The embodiments of the present application are described but not limited thereto. Ordinary technicians in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be defined by the claims.

Claims

1. A control circuit for driving an LED channel, the control circuit comprising: A power supply module, used for providing a power supply voltage; A pulse width modulation control circuit, used for receiving the power supply voltage provided by the power supply module and outputting a plurality of pulse width modulation control signals; A switch circuit, used to open or close according to the levels of the plurality of pulse width modulation control signals to control the lighting effects of the plurality of LED lamps; The falling edge of the first pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameter of the first LED lamp, so as to control the on and off of the first LED lamp in a periodic cycle; The rising edge of the second pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameter of the second LED lamp, so as to control the on and off of the second LED lamp in a periodic cycle; A rising edge of the second pulse width modulation control signal is before a falling edge of the first pulse width modulation control signal.

2. The control circuit according to claim 1, characterized in that: The pulse width modulation control circuit comprises: A first pulse width signal generating circuit, used for generating the first pulse width modulation control signal according to a periodic first clock signal; A second pulse width signal generating circuit, used for generating the second pulse width modulation control signal according to the periodic first clock signal; Wherein, the first pulse width signal generating circuit comprises: A preamplifier sub-circuit, configured to generate a preamplifier first pulse width modulation control signal according to the first clock signal; A delay subcircuit, used for obtaining the first pulse width modulation control signal according to the pre-placed first pulse width modulation control signal; The interval between the rising edge of the second pulse width modulation control signal and the falling edge of the first pulse width modulation control signal is adjusted by the delay value of the delay sub-circuit.

3. The control circuit according to claim 2, characterized in that: The front sub-circuit comprises: A first trigger, configured to be triggered by a periodic first clock signal and output a first pulse width modulation control signal; The delay subcircuit comprises: A first buffer, used for receiving the pre-set first pulse width modulation control signal, and obtaining the first pulse width modulation control signal after a delay; The second pulse width signal generating circuit comprises: A second trigger, configured to be triggered by the first clock signal and output a second pulse width modulation control signal; The interval between the rising edge of the second pulse width modulation control signal and the falling edge of the first pulse width modulation control signal is adjusted by the delay value of the first buffer.

4. The control circuit according to claim 2, characterized in that: The front sub-circuit comprises: A third trigger, configured to be triggered by the periodic first clock signal and output a first pulse width modulation control signal; The delay subcircuit comprises: a fourth trigger, configured to receive the first pulse width modulation control signal at the D terminal, and be triggered by the first clock signal of the same source, delay the first pulse width modulation control signal, and output the first pulse width modulation control signal; The second pulse width signal generating circuit comprises: a fifth trigger, configured to be triggered by the first clock signal and output a second pulse width modulation control signal; An interval between a rising edge of the second PWM control signal and a falling edge of the first PWM control signal is determined by a propagation delay between the third flip-flop and the fourth flip-flop and a period of the first clock signal.

5. The control circuit according to claim 2, characterized in that: The front sub-circuit comprises: a sixth trigger, configured to be triggered by the periodic first clock signal and output a first pulse width modulation control signal; The delay subcircuit comprises: A second buffer, used for receiving the first clock signal and obtaining a buffered first clock signal after delay; An inverter, configured to receive the buffered first clock and obtain a reverse buffered first clock signal after inverting the clock; A NAND logic circuit, used for receiving the reverse buffered first clock signal and performing a NAND logic operation on the first clock signal to obtain a second clock signal; a seventh trigger, configured to receive the first pulse width modulation control signal at the D terminal, and be triggered by the second clock signal to delay the first pulse width modulation control signal and output the first pulse width modulation control signal; The second pulse width signal generating circuit comprises: an eighth trigger, configured to be triggered by the first clock signal and output a second pulse width modulation control signal; The interval between the rising edge of the second PWM control signal and the falling edge of the first PWM control signal is determined by the propagation delay between the sixth flip-flop and the seventh flip-flop and the delay of the second buffer, the inverter, and the NAND logic circuit.

6. The control circuit according to claim 1, characterized in that: The center position of the third pulse width modulation control signal among the multiple pulse width modulation control signals is at a fixed position within the pulse width modulation control period, and the rising edge and the falling edge of the third pulse width modulation control signal change according to the duty cycle corresponding to the lighting effect parameters of the third LED lamp, so as to control the lighting of the third LED lamp in a periodic cycle.

7. The control circuit according to claim 6, characterized in that: The center position of the third pulse width modulation control signal is a fixed position within the pulse width modulation control period, including: The center position of the third pulse width modulation control signal is fixed at the center position of the pulse width modulation control period; or, The center position of the third pulse width modulation control signal is fixed at the position of the falling edge of the first pulse width modulation control signal; or, The center position of the third pulse width modulation control signal is fixed at the position of the rising edge of the second pulse width modulation control signal.

8. A control method for driving an LED channel, the control method comprising: Receive the power supply voltage provided by the power supply module and output a plurality of pulse width modulation control signals; Opening or closing the plurality of LED lamps according to the levels of the plurality of pulse width modulation control signals to control the lighting effects of the plurality of LED lamps; The falling edge of the first pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the rising edge changes according to the duty cycle corresponding to the lighting effect parameter of the first LED lamp, so as to control the on and off of the first LED lamp in a periodic cycle; The rising edge of the second pulse width modulation control signal among the plurality of pulse width modulation control signals is a fixed position, and the falling edge changes according to the duty cycle corresponding to the lighting effect parameter of the second LED lamp, so as to control the on and off of the second LED lamp in a periodic cycle; A rising edge of the second pulse width modulation control signal is before a falling edge of the first pulse width modulation control signal.

9. The control method according to claim 8, characterized in that: The center position of the third pulse width modulation control signal among the multiple pulse width modulation control signals is at a fixed position within the pulse width modulation control period, and the rising edge and the falling edge of the third pulse width modulation control signal change according to the duty cycle corresponding to the lighting effect parameters of the third LED lamp, so as to control the lighting of the third LED lamp in a periodic cycle.

10. The control method according to claim 9, characterized in that: The center position of the third pulse width modulation control signal is a fixed position within the pulse width modulation control period, including: The center position of the third pulse width modulation control signal is fixed at the center position of the pulse width modulation control period; or, The center position of the third pulse width modulation control signal is fixed at the position of the falling edge of the first pulse width modulation control signal; or, The center position of the third pulse width modulation control signal is fixed at the position of the rising edge of the second pulse width modulation control signal.

11. An LED system, comprising the control circuit for driving an LED channel according to any one of claims 1 to 7 and an LED lamp driven and controlled by the control circuit for driving the LED channel.

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