Constant-voltage PWM (Pulse Width Modulation) dimming control multi-load LED (Light Emitting Diode) circuit

Abstract

The utility model discloses a constant voltage PWM modulation dimming control multi-load LED circuit, relates to the technical field of driving, and aims to solve the problems of inconsistent multi-lamp switch response and poor dimming compatibility, the constant voltage PWM modulation dimming control multi-load LED circuit comprises a pre-stage driving module with an input end and an output end, the input end of the pre-stage driving module is connected with an input module, and the output end of the pre-stage driving module is connected with an output module. The input module is connected with an alternating-current input signal, the output end of the pre-stage driving module outputs a constant-voltage chopping signal, the driving circuit further comprises a post-stage driving module with an input end and an output end, the input end of the post-stage driving module is connected with the output end of the pre-stage driving module, and the output end of the post-stage driving module is connected with a load; according to the constant-voltage PWM modulation dimming control multi-load LED circuit of the utility model, a plurality of lamps can be driven and controlled by the same power supply, the problem that the plurality of lamps are turned on and turned off inconsistently is solved, the dimming and color modulation functions can be realized, and various dimming modes can be compatible.

Description

Technical Field

[0001] The utility model relates to the technical field of driving, in particular to a constant voltage PWM modulation dimming control multi-load LED circuit. Background Art

[0002] With the development of LED and driver technology, there are higher requirements for driver diversity and functionality. Lamps with functions such as dimming and color adjustment have gradually replaced conventional non-dimming lamps. Currently, lamp drivers are generally divided into built-in and external, and single lamps are generally sold with independent drivers. Indoor lighting, home lighting and other places generally require 5-10 lamps to meet the lighting needs of the whole house. This requires a wall switch or dimmer to control multiple lamps. This control method has the disadvantage of inconsistent startup or shutdown of multiple lamps, making it difficult to meet the needs of large-scale lighting. In addition, existing lamps use a single dimming method, which is not only costly but also has poor compatibility.

[0003] For example, there is a Chinese patent with publication number CN204482081U, which relates to an LED lamp switch dimming and color temperature adjustment circuit, including a push button switch, a thyristor dimmer, a power supply circuit, a dimming circuit and a color temperature adjustment circuit. The push button switch is connected to the input end of the power supply circuit through the thyristor dimmer, and the power supply circuit is electrically connected to the dimming circuit and the color temperature adjustment circuit respectively. The push button switch is connected to the input end of the dimming circuit and the input end of the color temperature adjustment circuit through the power supply circuit, and the thyristor dimmer is connected to the input end of the dimming circuit through the power supply circuit. The user's various light requirements can be met by using an ordinary switch and a thyristor dimmer, which is convenient and cost-effective. However, the Chinese patent with publication number CN204482081U requires an independent dimmer for each lamp load. When one switch is used to control multiple lamps throughout the house, due to the accuracy differences of different drivers themselves, the problem of asynchronous response will occur. Utility Model Content

[0004] In order to solve the problems of inconsistent switching responses of multiple lamps and poor dimming compatibility, the utility model proposes a constant voltage PWM modulation dimming control multi-load LED circuit, which can realize the control of multiple lamps by the same power supply, solve the problem of inconsistent startup and shutdown of multiple lamps, and at the same time realize dimming and color adjustment functions, and is compatible with multiple dimming modes.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions: a constant voltage PWM modulation dimming control multi-load LED circuit,

[0006] The invention comprises a front-stage driving module having an input end and an output end, wherein the input end of the front-stage driving module is connected to an input module, the input module is connected to an AC input signal, and the output end of the front-stage driving module outputs a constant voltage chopping signal. The invention also comprises a rear-stage driving module having an input end and an output end, wherein the input end of the rear-stage driving module is connected to the output end of the front-stage driving module, and the output end of the rear-stage driving module is connected to a load.

[0007] In this technical solution, a constant-voltage PWM modulation dimming control circuit for multi-load LEDs adopts a front-stage plus back-stage drive framework, replacing the traditional constant-current drive with a constant-voltage drive. The front-stage drive module outputs chopped voltages under different dimming states, and the DC-DC unit of the back-stage drive module processes the chopped voltage. By adopting such a circuit architecture, no matter how severe the dimming waveform interference input to the front-stage drive module is, as long as the output voltage is constant, it can be optimized by the back-stage drive module, thereby achieving compatibility with different dimming modules.

[0008] The present invention is further configured as follows: the front-stage driving module includes a constant voltage driving unit and a PWM chopping modulation unit, the input end of the constant voltage driving unit is connected to the input module, and the output ends of the constant voltage driving unit and the PWM chopping modulation unit are both connected to the rear-stage driving module.

[0009] In this technical solution, the constant voltage drive unit performs constant voltage processing on the incoming AC power and outputs a constant DC voltage; the PWM chopping modulation unit controls the output voltage by chopping and modulating the input signal, and the front-stage drive module realizes the conversion of AC power to constant voltage DC power through the constant voltage drive unit and the PWM chopping modulation unit, and outputs a constant voltage chopping signal.

[0010] The present invention is further configured as follows: the post-stage driving module includes a microcontroller provided with an input detection pin and a color temperature detection pin, the input end of the microcontroller is connected to a color temperature switching unit and a voltage monitoring unit, the output end of the microcontroller is connected to a DC-DC unit, and the DC-DC unit is connected to a load.

[0011] In this technical solution, the voltage monitoring unit can monitor the voltage of the input DC-DC unit and transmit it to the microcontroller; the color temperature switching module includes a dip switch and several resistors, which can realize the selection and switching of different color temperatures.

[0012] The present invention is further configured as follows: the DC-DC unit includes two DC-DC circuits connected in parallel, and the two DC-DC circuits are respectively connected to a high color temperature load and a low color temperature load.

[0013] In this technical solution, the DC-DC unit includes two DC-DC circuits in parallel, a DC-DC chip is provided in the DC-DC circuit, the output ends of the two DC-DC circuits are respectively connected to a high color temperature load and a low color temperature load, and the DC-DC unit of the subsequent drive module can process the chopped voltage.

[0014] The present invention is further configured as follows: the input of the microcontroller is a constant voltage chopping signal, and the output is two complementary PWM signals, and the two complementary PWM signals are transmitted to the DC-DC unit.

[0015] In this technical solution, the micro control unit receives the constant voltage chopping signal output by the front-stage driving module, and calculates the percentage of the total output current according to the voltage output by the voltage monitoring unit, thereby realizing the dimming function.

[0016] The present invention is further configured as follows: the color temperature switching unit includes at least one dip switch, and the dip switch is connected to a plurality of resistors.

[0017] In this technical solution, the color temperature switching module includes a dip switch and several resistors, which can realize the selection and switching of different color temperatures.

[0018] The present invention is further configured as follows: the input module includes a rectifier unit and at least one dimmer, and the rectifier unit is connected to the front-stage driver module.

[0019] In this technical solution, the input module includes a rectifier unit and at least one dimmer. This utility model's constant-voltage PWM modulation dimming control circuit for multi-load LEDs is compatible with Triac dimming, 0-10V dimming, and Triac & 0-10V dimming. It supports achieving different dimming modes by simply replacing the dimmer in the input module and adjusting the circuit connections, allowing users to select the desired mode based on their needs.

[0020] The present invention is further configured such that: the input module includes a Triac dimmer, the AC input signal is input to the Triac dimmer, and the input end of the constant voltage driving unit of the pre-stage driving module is connected to the Triac dimmer.

[0021] In this technical solution, when Triac dimming is adopted, the input module includes a rectifier unit and a Triac dimmer. The AC power is input to the rectifier unit through the Triac dimmer, and then the rectified dimming signal is input to the pre-stage driver module.

[0022] The present invention is further configured as follows: the input module includes a 0-10V dimmer, and the input end of the PWM chopping modulation unit of the front-stage driving module is connected to the 0-10V dimmer.

[0023] In this technical solution, when 0-10V dimming is used, the input module includes a rectifier unit and a 0-10V dimmer. The AC power is directly input into the rectifier unit, and then the rectified signal is input into the front-stage driver module. The 0-10V dimmer outputs an analog voltage signal of 0 to 10V to the front-stage driver module.

[0024] The present invention is further configured such that: the output voltage of the pre-stage driver module is less than 60V.

[0025] In this technical solution, the output voltage of the constant voltage driving unit of the front-stage driving module is a low voltage below 60V, which provides a low-voltage environment for lamp assembly and improves assembly safety.

[0026] The beneficial effects of the utility model are:

[0027] (1) The front-stage driver module uses a constant voltage drive instead of a constant current circuit, so that the same drive can drive multiple loads, effectively avoiding the problem of inconsistent dimming of multiple lamps;

[0028] (2) The dimmer acts on the constant voltage circuit and controls the output through the PWM chopping of the front-stage driver module. The rear-stage driver module receives the same modulated chopping voltage for conversion, achieving compatibility with different dimming modules;

[0029] (3) The constant voltage drive unit outputs a low voltage below 60V, which creates a low-voltage environment during lamp assembly and can greatly improve assembly safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a circuit module block diagram of a Triac dimming mode of a constant voltage PWM modulation dimming control multi-load LED circuit of the utility model.

[0031] Figure 2 This is a circuit module block diagram of a 0-10V dimming mode of a constant voltage PWM modulation dimming control multi-load LED circuit of the utility model.

[0032] Figure 3 This is a circuit module block diagram of a constant voltage PWM modulation dimming control multi-load LED circuit Triac & 0-10V dimming mode of the utility model.

[0033] Figure 4 This is a schematic diagram of a post-stage driver module for a constant voltage PWM modulation dimming control multi-load LED circuit of the utility model. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific implementation method described here is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a constant voltage PWM modulation dimming control multi-load LED circuit, which can use the same driver to simultaneously control multiple load lamps, preventing the inconsistency of multiple lamps turning on or off time caused by each lamp being equipped with an independent driver, and is compatible with multiple dimming modes.

[0037] like Figure 1 As shown, a constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment includes three modules: an input module, a front-stage driving module and a rear-stage driving module. These three modules are described in detail below.

[0038] The input module is the front-end module of a constant voltage PWM modulation dimming control multi-load LED circuit in this embodiment. It can be directly connected to the mains network. The input module can support AC power in the full voltage range of 100V to 347V as voltage input, and perform the most preliminary processing on the AC voltage to provide input signals for the next-level module.

[0039] The input module includes a rectifier unit and at least one dimmer. Because the constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment is compatible with multiple dimming modes, including Triac dimming, 0-10V dimming, and Triac & 0-10V dimming, it can support different dimming modes by simply replacing the dimmer in the input module and adjusting the circuit connections, allowing users to select different dimming modes based on their actual needs.

[0040] A constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment adopts Triac dimming mode. The circuit logic diagram is shown in FIG. Figure 1 .

[0041] In this embodiment, the input module includes a rectifier unit and a Triac dimmer. The AC power is input to the rectifier unit through the Triac dimmer, and the rectified dimming signal is then input to the pre-stage driver module.

[0042] The front-stage driving module performs constant voltage and modulation processing on the dimming signal. The front-stage driving module includes a constant voltage driving unit and a PWM chopping modulation unit, and the constant voltage driving unit and the PWM chopping modulation unit are connected in parallel.

[0043] In this embodiment, the dimming signal is directly input into the constant voltage drive unit in the first branch and is input into the PWM chopping modulation unit via a diode in the second branch. The constant voltage drive unit and the PWM chopping modulation unit are grounded respectively. The front-stage drive module is also provided with a field effect tube. The output end of the constant voltage drive unit is connected to the drain of the field effect tube, the output end of the PWM chopping modulation unit is connected to the gate of the field effect tube, and the source of the field effect tube is connected to the post-stage drive module.

[0044] The constant voltage drive unit processes the incoming AC power at a constant voltage and outputs a constant DC voltage; the PWM chopping modulation unit controls the output voltage by chopping and modulating the input signal, and the front-stage drive module realizes the conversion of AC power to constant voltage DC power.

[0045] The rear driver module includes a voltage monitoring unit, a color temperature switching unit, a micro control unit and a DC-DC unit. The circuit schematic diagram of the rear driver module is shown in the figure. Figure 4 .

[0046] The voltage monitoring unit can monitor the voltage of the input DC-DC unit and transmit it to the microcontroller.

[0047] like Figure 4 As shown, the color temperature switching module includes a dip switch and several resistors, which can realize the selection and switching of different color temperatures.

[0048] The microcontrol unit includes a microcontroller having a color temperature detection pin and an input detection pin. It can be understood that the microcontroller can be a single-chip microcomputer (MCU) of various models. The microcontroller includes at least two input pins, namely, a color temperature detection pin and an input detection pin, and two output pins.

[0049] The DC-DC unit includes two parallel DC-DC circuits, each of which is provided with a DC-DC chip. The output ends of the two DC-DC circuits are connected to a high color temperature load and a low color temperature load respectively.

[0050] It should be noted that the load may be a plurality of electrically connected LED lamps. In this embodiment, the load is 10 LED lamps connected in series.

[0051] The microcontroller unit receives the constant voltage chopping signal output by the front-stage driver module and calculates the percentage of the total output current according to the voltage output by the voltage monitoring unit, thereby realizing the dimming function.

[0052] The microcontrol unit can detect the color temperature information output by the color temperature switching unit to the color temperature detection pin, and allocate different PWM duty cycles to the two DC-DC circuits according to the color temperature information to realize the color adjustment function.

[0053] Due to the poor compatibility of different dimmers, different dimmers require different driving circuits to process different dimming signals differently. It is difficult to make different dimming methods compatible together. This results in different drivers requiring the purchase of different matching dimming devices, causing great inconvenience to users.

[0054] A constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment adopts a front-stage plus back-stage driving framework. The front-stage driving module outputs a chopped voltage under different dimming states, and the DC-DC unit of the back-stage driving module processes the chopped voltage. By adopting this circuit architecture, no matter how severe the dimming waveform interference input to the front-stage driving module is, as long as the output voltage is constant, it can be optimized by the back-stage driving module, thereby achieving compatibility with different dimming modules.

[0055] Example 2

[0056] This embodiment provides a constant voltage PWM modulation dimming control multi-load LED circuit, which can use the same driver to simultaneously control multiple load lamps, preventing the inconsistency of multiple lamps turning on or off time caused by each lamp being equipped with an independent driver, and is compatible with multiple dimming modes.

[0057] like Figure 1 As shown, a constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment includes three modules: an input module, a front-stage driving module and a rear-stage driving module. These three modules are described in detail below.

[0058] The input module is the front-end module of a constant voltage PWM modulation dimming control multi-load LED circuit in this embodiment. It can be directly connected to the mains network. The input module can support AC power in the full voltage range of 100V to 347V as voltage input, and perform the most preliminary processing on the AC voltage to provide input signals for the next-level module.

[0059] The input module includes a rectifier unit and at least one dimmer. Because the constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment is compatible with multiple dimming modes, including Triac dimming, 0-10V dimming, and Triac & 0-10V dimming, it can support different dimming modes by simply replacing the dimmer in the input module and adjusting the circuit connections, allowing users to select different dimming modes based on their actual needs.

[0060] A constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment adopts 0-10V dimming mode. The circuit logic diagram is shown in FIG. Figure 2 .

[0061] In this embodiment, the input module includes a rectifier unit and a 0-10V dimmer. The AC power is directly input into the rectifier unit, and the rectified signal is then input into the front-stage driver module. The 0-10V dimmer outputs an analog voltage signal of 0 to 10V to the front-stage driver module.

[0062] The front-stage driving module performs constant voltage and modulation processing on the dimming signal, and the front-stage driving module includes a constant voltage driving unit and a PWM chopping modulation unit.

[0063] In this embodiment, the rectified signal is directly input into the constant voltage drive unit, the 0-10V dimmer outputs an analog voltage signal of 0 to 10V to the PWM chopping modulation unit, the constant voltage drive unit and the PWM chopping modulation unit are grounded respectively, and the front-stage drive module is also provided with a field effect tube, the output end of the constant voltage drive unit is connected to the drain of the field effect tube, the output end of the PWM chopping modulation unit is connected to the gate of the field effect tube, and the source of the field effect tube is connected to the post-stage drive module.

[0064] The constant voltage drive unit processes the incoming AC power at a constant voltage and outputs a constant DC voltage; the PWM chopping modulation unit controls the output voltage by chopping and modulating the input signal, and the front-stage drive module realizes the conversion of AC power to constant voltage DC power.

[0065] The rear driver module includes a voltage monitoring unit, a color temperature switching unit, a micro control unit and a DC-DC unit. The circuit schematic diagram of the rear driver module is shown in the figure. Figure 4 .

[0066] The voltage monitoring unit can monitor the voltage of the input DC-DC unit and transmit it to the microcontroller.

[0067] like Figure 4 As shown, the color temperature switching module includes a dip switch and several resistors, which can realize the selection and switching of different color temperatures.

[0068] The microcontrol unit includes a microcontroller having a color temperature detection pin and an input detection pin. It can be understood that the microcontroller can be a single-chip microcomputer (MCU) of various models. The microcontroller includes at least two input pins, namely, a color temperature detection pin and an input detection pin, and two output pins.

[0069] The DC-DC unit includes two parallel DC-DC circuits, each of which is provided with a DC-DC chip. The output ends of the two DC-DC circuits are connected to a high color temperature load and a low color temperature load respectively.

[0070] It should be noted that the load may be a plurality of electrically connected LED lamps. In this embodiment, the load is 10 LED lamps connected in series.

[0071] The microcontroller unit receives the constant voltage chopping signal output by the front-stage driver module and calculates the percentage of the total output current according to the voltage output by the voltage monitoring unit, thereby realizing the dimming function.

[0072] The microcontrol unit can detect the color temperature information output by the color temperature switching unit to the color temperature detection pin, and allocate different PWM duty cycles to the two DC-DC circuits according to the color temperature information to realize the color adjustment function.

[0073] Due to the poor compatibility of different dimmers, different dimmers require different driving circuits to process different dimming signals differently. It is difficult to make different dimming methods compatible together. This results in different drivers requiring the purchase of different matching dimming devices, causing great inconvenience to users.

[0074] A constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment adopts a front-stage plus back-stage driving framework. The front-stage driving module outputs a chopped voltage under different dimming states, and the DC-DC unit of the back-stage driving module processes the chopped voltage. By adopting this circuit architecture, no matter how severe the dimming waveform interference input to the front-stage driving module is, as long as the output voltage is constant, it can be optimized by the back-stage driving module, thereby achieving compatibility with different dimming modules.

[0075] Example 3

[0076] This embodiment provides a constant voltage PWM modulation dimming control multi-load LED circuit, which can use the same driver to simultaneously control multiple load lamps, preventing the inconsistency of multiple lamps turning on or off time caused by each lamp being equipped with an independent driver, and is compatible with multiple dimming modes.

[0077] like Figure 1 As shown, a constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment includes three modules: an input module, a front-stage driving module and a rear-stage driving module. These three modules are described in detail below.

[0078] The input module is the front-end module of a constant voltage PWM modulation dimming control multi-load LED circuit in this embodiment. It can be directly connected to the mains network. The input module can support AC power in the full voltage range of 100V to 347V as voltage input, and perform the most preliminary processing on the AC voltage to provide input signals for the next-level module.

[0079] The input module includes a rectifier unit and at least one dimmer. Because the constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment is compatible with multiple dimming modes, including Triac dimming, 0-10V dimming, and Triac & 0-10V dimming, it can support different dimming modes by simply replacing the dimmer in the input module and adjusting the circuit connections, allowing users to select different dimming modes based on their actual needs.

[0080] A constant voltage PWM modulation dimming control multi-load LED circuit of this embodiment adopts Triac&0-10V dimming mode. The circuit logic diagram is shown in FIG. Figure 3 .

[0081] In this embodiment, the input module includes a rectifier unit, a Triac dimmer, and a 0-10V dimmer. AC power is input to the Triac dimmer, and the rectified dimming signal is input to the pre-stage driver module. The 0-10V dimmer outputs an analog voltage signal of 0 to 10V to the pre-stage driver module.

[0082] The front-stage driving module performs constant voltage and modulation processing on the dimming signal. The front-stage driving module includes a constant voltage driving unit and a PWM chopping modulation unit, and the constant voltage driving unit and the PWM chopping modulation unit are connected in parallel.

[0083] In this embodiment, the rectified dimming signal is directly input into the constant voltage drive unit in the first branch and is input into the PWM chopping modulation unit via a diode in the second branch. The 0-10V dimmer outputs an analog voltage signal of 0 to 10V to the PWM chopping modulation unit. The constant voltage drive unit and the PWM chopping modulation unit are grounded respectively. The front-stage drive module is also provided with a field effect transistor. The output end of the constant voltage drive unit is connected to the drain of the field effect transistor, the output end of the PWM chopping modulation unit is connected to the gate of the field effect transistor, and the source of the field effect transistor is connected to the post-stage drive module.

[0084] The constant voltage drive unit processes the incoming AC power at a constant voltage and outputs a constant DC voltage; the PWM chopping modulation unit controls the output voltage by chopping and modulating the input signal, and the front-stage drive module realizes the conversion of AC power to constant voltage DC power.

[0085] The rear driver module includes a voltage monitoring unit, a color temperature switching unit, a micro control unit and a DC-DC unit. The circuit schematic diagram of the rear driver module is shown in the figure. Figure 4 .

[0086] The voltage monitoring unit can monitor the voltage of the input DC-DC unit and transmit it to the microcontroller.

[0087] like Figure 4As shown, the color temperature switching module includes a dip switch and several resistors, which can realize the selection and switching of different color temperatures.

[0088] The microcontrol unit includes a microcontroller having a color temperature detection pin and an input detection pin. It can be understood that the microcontroller can be a single-chip microcomputer (MCU) of various models. The microcontroller includes at least two input pins, namely, a color temperature detection pin and an input detection pin, and two output pins.

[0089] The DC-DC unit includes two parallel DC-DC circuits, each of which is provided with a DC-DC chip. The output ends of the two DC-DC circuits are connected to a high color temperature load and a low color temperature load respectively.

[0090] It should be noted that the load may be a plurality of electrically connected LED lamps. In this embodiment, the load is 10 LED lamps connected in series.

[0091] The microcontroller unit receives the constant voltage chopping signal output by the front-stage driver module and calculates the percentage of the total output current according to the voltage output by the voltage monitoring unit, thereby realizing the dimming function.

[0092] The microcontrol unit can detect the color temperature information output by the color temperature switching unit to the color temperature detection pin, and allocate different PWM duty cycles to the two DC-DC circuits according to the color temperature information to realize the color adjustment function.

[0093] Due to the poor compatibility of different dimmers, different dimmers require different driving circuits to process different dimming signals differently. It is difficult to make different dimming methods compatible together. This results in different drivers requiring the purchase of different matching dimming devices, causing great inconvenience to users.

[0094] A constant-voltage PWM modulation dimming control circuit for multi-load LEDs in this embodiment adopts a front-stage plus back-stage driving framework. The front-stage driving module outputs a chopped voltage under different dimming states, and the DC-DC unit of the back-stage driving module processes the chopped voltage. By adopting this circuit architecture, no matter how severe the dimming waveform interference input to the front-stage driving module is, as long as the output voltage is constant, it can be optimized by the back-stage driving module, thereby achieving compatibility with different dimming modules.

Claims

1. A constant voltage PWM modulation dimming control multi-load LED circuit, characterized in that: include: A front-stage driving module having an input end and an output end, wherein the input end of the front-stage driving module is connected to the input module, the input module is connected to an AC input signal, and the output end of the front-stage driving module outputs a constant voltage chopping signal; and a rear-stage driving module having an input end and an output end, wherein the input end of the rear-stage driving module is connected to the output end of the front-stage driving module, and the output end of the rear-stage driving module is connected to a load.

2. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 1, characterized in that: The front-stage driving module includes a constant voltage driving unit and a PWM chopping modulation unit. The input end of the constant voltage driving unit is connected to the input module, and the output ends of the constant voltage driving unit and the PWM chopping modulation unit are both connected to the rear-stage driving module.

3. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 1, characterized in that: The post-stage driving module includes a microcontroller provided with an input detection pin and a color temperature detection pin, the input end of the microcontroller is connected to a color temperature switching unit and a voltage monitoring unit, the output end of the microcontroller is connected to a DC-DC unit, and the DC-DC unit is connected to a load.

4. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 3, characterized in that: The DC-DC unit includes two DC-DC circuits connected in parallel, and the two DC-DC circuits are respectively connected to a high color temperature load and a low color temperature load.

5. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 3, characterized in that: The input of the microcontroller is a constant voltage chopping signal, and the output is two complementary PWM signals, and the two complementary PWM signals are transmitted to the DC-DC unit.

6. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 3, characterized in that: The color temperature switching unit includes at least one dip switch, and the dip switch is connected to a plurality of resistors.

7. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 1, characterized in that: The input module includes at least one dimmer and a rectifier unit, and the rectifier unit is connected to the front-stage driving module.

8. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 2, characterized in that: The input module includes a Triac dimmer connected to the input end of the constant voltage driving unit, and the AC input signal is input to the Triac dimmer.

9. The constant voltage PWM modulation dimming control multi-load LED circuit according to claim 2, characterized in that: The input module includes a 0-10V dimmer connected to the input end of the PWM chopping modulation unit.

10. A constant voltage PWM modulation dimming control multi-load LED circuit according to any one of claims 1 to 9, characterized in that: The output voltage of the pre-stage driver module is less than 60V.

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