TWI716152B - Dimming circuit, dimmer having the same and controller thereof - Google Patents

Abstract

A dimming circuit is provided, which may include a dynamic load and a control voltage input terminal. One end of the dynamic load may be coupled to the positive terminal of the output of a converter and the positive terminal of a main load; the other end of the dynamic load may be coupled to the negative terminal of the output of the converter and the negative terminal of the main load; the dynamic load may receive the output current from the converter. The control voltage input terminal may be coupled to a controller and receive the control voltage inputted by the controller. The first branch current, passing through the dynamic load, of the output current may be adjusted by the control voltage via the dynamic load, such that the second branch current, passing through the main load, can be changed, of the output current.

Description

Dimming circuit, dimmer with the dimming circuit and its controller

The present invention relates to a dimming circuit, especially a dimming circuit with dynamic load. The present invention also relates to a dimmer including the dimming circuit and its controller.

Existing dimmers usually dimming LED lights through converters, and currently the most commonly used dimming modes include linear dimming mode, pulse width modulation (PWM) dimming mode and hybrid dimming mode.

Please refer to Figure 1, which is a schematic diagram of the linear dimming mode of the existing dimmer. As shown in the figure, the horizontal axis represents the control command, and the vertical axis represents the brightness; the control command can be voltage or duty cycle, etc., or the control command can be a DALI protocol control command. Linear dimming mode can achieve better performance when the brightness level is between 100% and 5% of the maximum brightness. However, because the linear dimming mode is prone to stroboscopic phenomenon when the maximum brightness is less than 5% of the maximum brightness; therefore, generally speaking, the lower limit of the dimming of the linear dimming mode can only reach 1% of the maximum brightness of the LED lamp~ 5%.

Please refer to Figure 2, which is a schematic diagram of the pulse width modulation dimming mode of the existing dimmer. As shown in the figure, the horizontal axis represents the control command, and the vertical axis represents the brightness; the control command can be voltage or duty cycle, etc., or the control command can be a DALI protocol control command. Pulse width modulation dimming mode can change the brightness of LED lights by adjusting the duty cycle (such as 10%, 50%, 60% and 100% marked on the horizontal axis). However, the pulse width modulation dimming mode is prone to low ripple stroboscopic phenomenon, but it can achieve more Low dimming limit; Generally speaking, the dimming limit of pulse width modulation dimming mode can reach 0.1% of the maximum brightness of the LED lamp.

Please refer to Figure 3, which is a schematic diagram of the hybrid dimming mode of the existing dimmer. As shown in the figure, the horizontal axis represents the control command, and the vertical axis represents the brightness; the control command can be voltage or duty cycle, etc., or the control command can be a DALI protocol control command. Hybrid dimming mode integrates linear dimming mode and pulse width modulation dimming mode. It uses linear dimming in one brightness range (such as 100%~10% of maximum brightness), and uses linear dimming in another brightness range (such as maximum brightness). Within 10%~0.1%) of pulse width modulation dimming. However, the hybrid dimming mode has the advantages of both linear dimming mode and pulse width modulation dimming mode, but its lower dimming limit can only reach 0.1% of the maximum brightness of the LED lamp.

In view of the above-mentioned problems of the prior art, one of the objectives of the present invention is to provide a dimming circuit, a dimmer having the dimming circuit, and a controller thereof, so as to solve various limitations of the existing dimming technology.

According to one of the objectives of the present invention, a dimming circuit is provided, which can include a dynamic load and a control voltage input terminal. One end of the dynamic load can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the other end of the dynamic load can be connected to the negative pole of the output end of the converter and the negative pole of the main load, so that the dynamic load can receive the output of the converter Current. The control voltage input terminal can be connected to the controller and receive the control voltage output by the controller. Among them, the first branch current of the output current flowing through the dynamic load can be adjusted by the control voltage through the dynamic load to change the second branch current of the output current flowing through the main load.

In one embodiment, the dynamic load can include a resistance element and an operational amplifier. The first end of the resistance element can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the second end of the resistance element can be connected to the output of the operational amplifier. Terminal, the third terminal of the resistance element can be connected to the reverse output of the operational amplifier The input terminal is connected, the fourth terminal of the resistance element can be connected to the negative terminal of the output terminal of the converter and the negative terminal of the main load, and the control voltage input terminal can be connected to the non-inverting input terminal of the controller and the operational amplifier.

In one embodiment, the resistance element may include two or more of a metal oxide half field effect transistor (MOSFET), a bipolar junction transistor, a semiconductor element (BJT), and a resistor.

In one embodiment, the dynamic load can include a transistor, a resistor, and an operational amplifier. The drain of the transistor can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the gate of the transistor can be connected to the output of the operational amplifier. The source of the transistor can be connected to one end of the resistor and the reverse input terminal of the operational amplifier. The other end of the resistor can be connected to the negative pole of the converter output terminal and the negative pole of the main load. The control voltage input terminal can be connected to the control The non-inverting input terminal of the amplifier and the operational amplifier are connected.

In one embodiment, the first branch current may be equal to the control voltage divided by the resistance value of the resistor.

In one embodiment, the converter may be a Buck converter, a Boost converter, a Buck-Boost converter or other similar components.

In an embodiment, the controller may be a microcontroller (MCU) or a processor.

According to one of the objectives of the present invention, a dimmer is further provided, which may include a converter and a dimming circuit. The dimming circuit can include dynamic load and control voltage input terminals. One end of the dynamic load can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the other end of the dynamic load can be connected to the negative pole of the output end of the converter and the main load. The negative pole is connected so that the dynamic load can receive the output current of the converter, and the control voltage input can be connected to the controller and receive the control voltage output by the controller. Among them, the first branch current of the output current flowing through the dynamic load can be adjusted by the control voltage to change the second branch current of the output load current.

In one embodiment, the dynamic load can include a resistance element and an operational amplifier. The first end of the resistance element can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the second end of the resistance element can be connected to the output of the operational amplifier. The third end of the resistance element can be connected to the reverse input end of the operational amplifier, the fourth end of the resistance element can be connected to the negative pole of the output end of the converter and the negative pole of the main load, and the control voltage input end can be connected to the controller Connect with the non-inverting input terminal of the operational amplifier.

In one embodiment, the resistance element may include two or more of MOSFETs, bipolar junction transistors, semiconductor elements, and resistors.

In one embodiment, the dynamic load can include a transistor, a resistor, and an operational amplifier. The drain of the transistor can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the gate of the transistor can be connected to the output of the operational amplifier. The source of the transistor can be connected to one end of the resistor and the reverse input terminal of the operational amplifier. The other end of the resistor can be connected to the negative pole of the converter output terminal and the negative pole of the main load. The control voltage input terminal can be connected to the control The non-inverting input terminal of the amplifier and the operational amplifier are connected.

In one embodiment, the first branch current may be equal to the control voltage divided by the resistance value of the resistor.

In an embodiment, the converter may be a buck converter, a boost converter, a buck-boost converter or other similar components.

In an embodiment, the controller may be a microcontroller or a processor.

According to one of the objectives of the present invention, a controller is further provided, which may include a detection circuit and a control circuit. The detection circuit can be connected with the converter to detect the output current of the converter, the first branch current of the output current can flow through the dimming circuit, and the second branch current of the output current can flow through the main load. The control circuit can be connected to the control voltage input end of the detection circuit and the dimming circuit and receive control commands. The control circuit can adjust the control voltage input to the control voltage input terminal according to the control command and the output current, so that the first branch current can be adjusted through the control voltage to change the second branch current.

In one embodiment, the dynamic load can include a resistance element and an operational amplifier. The first end of the resistance element can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the second end of the resistance element can be connected to the output of the operational amplifier. The third end of the resistance element can be connected to the reverse input end of the operational amplifier, the fourth end of the resistance element can be connected to the negative pole of the output end of the converter and the negative pole of the main load, and the control voltage input end can be connected to the control circuit Connect with the non-inverting input terminal of the operational amplifier.

In one embodiment, the resistance element may include two or more of MOSFETs, bipolar junction transistors, semiconductor elements, and resistors.

In one embodiment, the dynamic load can include a transistor, a resistor, and an operational amplifier. The drain of the transistor can be connected to the positive pole of the output terminal of the converter and the positive pole of the main load, and the gate of the transistor can be connected to the output of the operational amplifier. The source of the transistor can be connected to one end of the resistor and the reverse input terminal of the operational amplifier. The other end of the resistor can be connected to the negative pole of the converter output terminal and the negative pole of the main load. The control voltage input terminal can be connected to the control The circuit and the non-inverting input terminal of the operational amplifier are connected.

In one embodiment, the first branch current may be equal to the control voltage divided by the resistance value of the resistor.

In an embodiment, the converter may be a buck converter, a boost converter, a buck-boost converter or other similar components, and the controller may be a microcontroller, a processor or other similar components element.

In summary, according to the dimming circuit of the present invention, the dimmer having the dimming circuit and the controller thereof, it can have one or more of the following advantages:

(1) In one embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to implement a special dynamic load dimming mode, so that the lower limit of the dimmer can reach the LED The brightness of 0.01% or lower of the maximum brightness of the lamp effectively improves the performance of the dimmer and improves the stability of the converter at low brightness.

(2) In one embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to implement a special dynamic load dimming mode, so that the adjacent dimming levels of the dimmer The interval between the LED lights can reach 0.01% of the maximum brightness of the LED lamp, so a more linear and delicate dimming effect can be achieved, which effectively improves the efficiency of the dimmer.

(3) In one embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which implements a special dynamic load dimming mode, so it will not produce stroboscopic and low-ripple stroboscopic phenomena, so it can further Improved the efficiency of the dimmer.

(4) In an embodiment of the present invention, the dimmer can use the dynamic load in different dimming modes, including linear dimming mode, pulse width dimming mode, and linear and pulse width integrated dimming mode, thereby complying with different dimming modes. Therefore, the application is more extensive.

(5) In an embodiment of the present invention, the dynamic load dimming circuit of the dimmer can be realized by a simple circuit, so the desired effect can be achieved without a significant increase in cost, which is of great commercial value.

1: dimmer

11: converter

12: Dimming circuit

2: Controller

21: Detection circuit

22: Control circuit

DL: dynamic load

Ra: resistance element

P1: The first end of the resistance element

P2: The second end of the resistance element

P3: The third terminal of the resistance element

P4: The fourth terminal of the resistance element

M: Transistor

R: resistance

AP: operational amplifier

T: Control voltage input terminal

C+: The positive pole of the output terminal of the converter

C-: The negative pole of the output terminal of the converter

L: main load

L+: Positive pole of main load

L-: negative pole of main load

Vc: control voltage

Vin: input voltage

Io: output current

I1: First branch current

I2: Second branch current

Dm: control command

Figure 1 is a schematic diagram of the linear dimming mode of the existing dimmer.

Figure 2 is a schematic diagram of the pulse width modulation dimming mode of the existing dimmer.

Figure 3 is a schematic diagram of the hybrid dimming mode of the existing dimmer.

Figure 4 is a circuit diagram of a dimmer according to an embodiment of the present invention.

Figure 5 is a circuit diagram of a dimming circuit according to an embodiment of the present invention.

Figure 6 is a circuit diagram of a dimming circuit according to an embodiment of the present invention.

Figure 7 is a schematic diagram of a hybrid dimming mode integrating dynamic load dimming mode according to an embodiment of the present invention.

The following will describe embodiments of the dimming circuit according to the present invention, the dimmer having the dimming circuit, and the controller thereof with reference to related drawings. For clarity and convenience of the description of the drawings, the components in the drawings are The size and proportion may be exaggerated or reduced. In the following description and/or the scope of the patent application, when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or an intervening element may be present; and when referring to an element When "directly connected" or "directly coupled" to another element, there is no intervening element, and other words used to describe the relationship between elements or layers should be interpreted in the same way. To facilitate understanding, the same elements in the following embodiments are described with the same symbols.

Please refer to FIG. 4, which is a circuit diagram of a dimmer according to an embodiment of the present invention. As shown in the figure, the dimmer 1 may include a converter 11 and a dimming circuit 12. The converter 11 is connected to the detection circuit 21 of the controller 2, and the dimming circuit 12 is connected to the control circuit 22 of the controller 2. In an embodiment, the controller 22 may be a microcontroller (MCU), a processor or other similar elements.

The input terminal of the converter 11 receives the input voltage Vin and generates an output current Io. In an embodiment, the converter 11 may be a Buck converter, a Boost converter, a Buck-Boost converter or other similar components; The input voltage Vin can be a DC input voltage or an AC input voltage.

The dimming circuit 12 includes a dynamic load DL and a control voltage input terminal T. One end of the dynamic load DL is connected to the positive pole C+ of the output terminal of the converter 11 and the positive pole L+ of the main load L (such as LED lights), and the other end of the dynamic load DL is connected to the negative pole C- of the output terminal of the converter 11 and the main load L The negative L-connection. The control voltage input terminal T is connected to the controller 2 and receives the control voltage Vc output by the controller 2.

It can be seen from the figure that when the output current Io flows through one end of the dynamic load DL, it will be divided into a first branch current I1 and a second branch current I2. The first branch current I1 flows through the dynamic load DL, and the second branch current I2 flows through the main load L to drive the main load L.

The detection circuit 21 of the controller 2 detects the output current Io of the converter 11. The control circuit 22 of the controller 2 receives the control command Dm, and adjusts the control voltage Vc input to the control voltage input terminal T according to the control command Dm and the output current Io. Through the above-mentioned circuit design, the first branch current I1 can be adjusted through the control voltage Vc to change the second branch current I2 driving the main load L to dimming the main load L.

Since the dimmer 1 can adjust the second branch current I2 driving the main load L through the dynamic load DL of the dimming circuit 12, this dynamic load dimming mode enables the lower limit of the dimmer 1 to reach the maximum brightness of the LED lamp 0.01% of the dimmer, the performance of the dimmer 1 is significantly improved, and the stability of the converter 11 at low brightness can be significantly increased.

In addition, this dynamic load dimming mode can also enable the interval between adjacent dimming levels of the dimmer 1 to reach 0.01% of the maximum brightness of the LED lamp, so it can achieve a more linear and delicate dimming effect. The efficiency of the dimmer 1 is greatly improved. In addition, this dynamic load dimming mode does not produce stroboscopic and low-ripple stroboscopic phenomena, so it can further improve the performance of the dimmer.

Of course, the above is only an example. The circuit structure of the dimmer 1 of this embodiment and the coordination of its components can be changed according to actual needs, and the present invention is not limited thereto.

Please refer to FIG. 5, which is a circuit diagram of a dimming circuit according to an embodiment of the present invention. As shown in the figure, the dimming circuit 12 may include a dynamic load DL and a control voltage input terminal T.

The dynamic load DL includes a resistance element Ra and an operational amplifier AP. The first terminal P1 of the resistance element Ra is connected to the positive electrode C+ of the output terminal of the converter and the positive electrode L+ of the main load; the second terminal P2 of the resistance element Ra is connected to the output terminal of the operational amplifier AP; the third terminal P3 of the resistance element Ra Connect with the reverse input terminal of the operational amplifier AP; the fourth terminal P4 of the resistance element Ra is connected with the negative C- of the output terminal of the converter and the negative L- of the main load. In one embodiment, the resistance element Ra may include two or more of a metal oxide half field effect transistor (MOSFET), a bipolar junction transistor (BJT), a semiconductor element, and a resistor.

The control voltage input terminal T is connected to the non-inverting input terminal of the control circuit 22 and the operational amplifier AP, and receives the control voltage Vc input by the controller.

Similarly, when the output current Io flows through one end of the dynamic load DL, it will be divided into a first branch current I1 and a second branch current I2. The first branch current I1 flows through the resistance element Ra, and the second branch current I2 flows through the main load L to drive the main load L. Through the above-mentioned circuit design and the above-mentioned circuit design, the first branch current I1 can be adjusted through the control voltage Vc to change the second branch current I2 driving the main load L to dimming the main load L.

Of course, the above are only examples. The circuit structure of the dimming circuit 12 and the coordination relationship of its components in this embodiment can be changed according to actual needs, and the present invention is not limited thereto.

Please refer to FIG. 6, which is a circuit diagram of a dimming circuit according to an embodiment of the present invention. As shown in the figure, the dimming circuit 12 may include a dynamic load DL and a control voltage input terminal T.

The dynamic load DL includes a transistor M, a resistor R and an operational amplifier AP; in this embodiment, the transistor M is a metal oxide semi-field effect transistor. The drain of the transistor M is connected to the positive pole C+ of the output terminal of the converter and the positive pole L+ of the main load; the gate of the transistor M is connected to the output terminal of the operational amplifier AP; The source of the crystal M is connected to one end of the resistor R and the reverse input end of the operational amplifier AP; the other end of the resistor R is connected to the negative C- of the output end of the converter, the negative L- of the main load and the control voltage input T .

The control voltage input terminal T is connected to the non-inverting input terminal of the operational amplifier AP and receives the control voltage Vc input by the controller.

Similarly, when the output current Io flows through one end of the dynamic load DL, it will be divided into a first branch current I1 and a second branch current I2. The first branch current I1 flows through the resistance element Ra, and the second branch current I2 flows through the main load L to drive the main load L. The first branch current I1 can be expressed by the following formula (1): I1=Vc/R................................ ....................................(1)

It can be seen from equation (1) that the first branch current I1 is equal to the control voltage Vc divided by the resistance value of the resistor R. For example, if the resistance value of the resistor R is 1kΩ and the control voltage Vc is 0~3.3V, the first branch current I1 is 0~3.3mA.

Through the above-mentioned circuit design, the first branch current I1 can be adjusted through the control voltage Vc to change the second branch current I2 driving the main load L to dimming the main load L.

Of course, the above are only examples. The circuit structure of the dimming circuit 12 and the coordination relationship of its components in this embodiment can be changed according to actual needs, and the present invention is not limited thereto.

It is worth mentioning that the lower dimming limit of the existing linear dimming mode can only reach 1%~5% of the maximum brightness of the LED lamp, while the existing pulse width modulation (PWM) dimming mode and hybrid dimming mode The lower limit of dimming is only 0.1% of the maximum brightness of the LED lamp, so the performance of the linear dimming mode and the pulse width modulation dimming mode can no longer meet the needs of practical applications. On the contrary, according to the embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to implement a special dynamic load dimming mode, so that the lower limit of the dimmer can reach the LED lamp. 0.01% of the maximum brightness Or lower brightness effectively improves the performance of the dimmer and improves the stability of the converter at low brightness.

Furthermore, according to an embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to perform a special dynamic load dimming mode, so that the adjacent dimming levels of the dimmer The interval can reach 0.01% of the maximum brightness of the LED light, so a more linear and delicate dimming effect can be achieved, which effectively improves the efficiency of the dimmer.

In addition, the existing linear dimming mode and pulse width modulation dimming mode are prone to stroboscopic and low-ripple stroboscopic phenomena respectively, which seriously affect the performance of the dimmer. On the contrary, according to the embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which can perform a special dynamic load dimming mode, so it will not produce stroboscopic and low-ripple stroboscopic phenomena, so it can further Improved the efficiency of the dimmer.

In addition, according to the embodiment of the present invention, the dynamic load dimming circuit of the dimmer can be realized by a simple circuit, so the desired effect can be achieved without a substantial increase in cost, which is of great commercial value.

Please refer to FIG. 7, which is a schematic diagram of a hybrid dimming mode integrated with a dynamic load dimming mode according to an embodiment of the present invention. As shown in the figure, the horizontal axis represents the control command, and the vertical axis represents the brightness; the control command can be voltage or duty cycle, etc., or the control command can be a DALI protocol control command. The dynamic load dimming mode can be integrated with one or both of the linear dimming mode and the pulse width modulation dimming mode to meet different requirements. In this embodiment, the dimmer adopts linear dimming mode when the brightness level is between 100% and 10% of the maximum brightness, and uses pulse width modulation modulation when the brightness level is between 10% and 3% of the maximum brightness. Light mode, and the dynamic load dimming mode is used when the brightness level is between 3% and 0.01% of the maximum brightness. The brightness threshold of the dynamic load dimming mode can be changed according to actual needs; For example, in another embodiment, the brightness threshold of the dynamic load dimming mode may be 0.1%, 0.5%, 6%, or 10% of the maximum brightness.

It can be seen from the above that in this embodiment, the dimmer can use the dynamic load in different dimming modes, including linear dimming mode, pulse width dimming mode, and linear and pulse width integrated dimming mode, thereby complying with different dimming modes. Demand, so the application is more extensive.

In summary, according to the embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to perform a special dynamic load dimming mode, so that the lower limit of the dimmer can reach The brightness of 0.01% or lower of the maximum brightness of the LED lamp effectively improves the efficiency of the dimmer and can improve the stability of the converter at low brightness.

Furthermore, according to an embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which has a special circuit design to perform a special dynamic load dimming mode, so that the adjacent dimming levels of the dimmer The interval can reach 0.01% of the maximum brightness of the LED light, so a more linear and delicate dimming effect can be achieved, which effectively improves the efficiency of the dimmer.

In addition, according to the embodiment of the present invention, the dimmer includes a dimming circuit with a dynamic load, which implements a special dynamic load dimming mode, so it will not produce stroboscopic and low-ripple stroboscopic phenomena, so it can further improve The effectiveness of the dimmer.

In addition, according to the embodiment of the present invention, the dimmer can use the dynamic load in different dimming modes, including linear dimming mode, pulse width dimming mode, and linear and pulse width integrated dimming mode, thereby meeting different needs , So the application is more extensive.

Furthermore, according to the embodiment of the present invention, the dimming circuit of the dynamic load of the dimmer can be realized through a simple circuit, so the desired effect can be achieved without a substantial increase in cost, which is of great commercial value.

It can be seen that the present invention has indeed achieved the desired enhancement effect by breaking through the previous technology, and it is not easy to think about by those who are familiar with the art. Its progressiveness and practicability have clearly met the requirements for patent application. Yan has filed a patent application in accordance with the law, and I implore your office to approve this invention patent application to encourage creativity and make it easy.

The above description is only illustrative, and not restrictive. Any other equivalent modifications or alterations that do not depart from the spirit and scope of the present invention should be included in the scope of the attached patent application.

1: dimmer

11: converter

12: Dimming circuit

2: Controller

21: Detection circuit

22: Control circuit

DL: dynamic load

T: Control voltage input terminal

C+: The positive pole of the output terminal of the converter

C-: The negative pole of the output terminal of the converter

L: main load

L+: Positive pole of main load

L-: negative pole of main load

Vc: control voltage

Vin: input voltage

Io: output current

I1: First branch current

I2: Second branch current

Dm: control command

Claims (20)

A dimming circuit comprising: a dynamic load, one end of which is connected to the positive pole of the output terminal of a converter and the positive pole of a main load, and the other end is connected to the negative pole of the output terminal of the converter and the negative pole of the main load , Enabling the dynamic load to receive an output current of the converter; and a control voltage input terminal connected to a controller and receiving a control voltage output by the controller, the control voltage being generated by the controller according to a control command ; Wherein, the first branch current of the output current flowing through the dynamic load is adjusted through the control voltage to change the second branch current of the output current flowing through the main load. The dimming circuit described in item 1 of the scope of patent application, wherein the dynamic load includes a resistance element and an operational amplifier, and the first end of the resistance element is connected to the positive pole of the output terminal of the converter and the positive pole of the main load , The second end of the resistance element is connected to the output end of the operational amplifier, the third end of the resistance element is connected to the reverse input end of the operational amplifier, and the fourth end of the resistance element is connected to the output end of the converter The negative pole is connected to the negative pole of the main load, and the control voltage input terminal is connected to the non-inverting input terminal of the controller and the operational amplifier. The dimming circuit according to the second item of the scope of patent application, wherein the resistance element includes two or more of a metal oxide half field effect transistor, a bipolar junction transistor, a semiconductor element and a resistor. The dimming circuit described in item 1 of the scope of patent application, wherein the dynamic load includes a transistor, a resistor and an operational amplifier, the drain of the transistor and the positive pole of the output terminal of the converter and the main load Positive connection, the gate of the transistor is connected to the output of the operational amplifier, the source of the transistor is connected to one end of the resistor and the reverse input of the operational amplifier, and the other end of the resistor Connected with the negative pole of the output terminal of the converter and the negative pole of the main load, the control voltage input terminal is connected with the non-inverting input terminal of the controller and the operational amplifier. The dimming circuit described in item 4 of the scope of patent application, wherein the first branch current is equal to the control voltage divided by the resistance value of the resistor. The dimming circuit as described in item 1 of the scope of patent application, wherein the converter is a buck converter, a boost converter or a buck-boost converter. In the dimming circuit described in item 1 of the scope of patent application, the controller is a microcontroller or a processor. A dimmer comprising: a converter; and a dimming circuit comprising a dynamic load and a control voltage input terminal, one terminal of the dynamic load and the positive pole of the output terminal of the converter and the positive pole of a main load The other end of the dynamic load is connected to the negative pole of the output terminal of the converter and the negative pole of the main load, so that the dynamic load receives an output current of the converter, and the control voltage input terminal is connected to a controller and receives The controller outputs a control voltage, the control voltage is generated by the controller according to a control command; wherein, the output current flowing through the dynamic load a first branch current is adjusted by the control voltage to change the output current flow A second branch current through one of the main loads. The dimmer described in item 8 of the scope of patent application, wherein the dynamic load includes a resistance element and an operational amplifier, and the first end of the resistance element is connected to the positive pole of the output terminal of the converter and the positive pole of the main load , The second end of the resistance element is connected to the output end of the operational amplifier, the third end of the resistance element is connected to the inverting input end of the operational amplifier, and the fourth end of the resistance element is connected to the converter The negative pole of the output terminal of the inverter is connected to the negative pole of the main load, and the control voltage input terminal is connected to the non-inverting input terminal of the controller and the operational amplifier. According to the dimmer described in claim 9, wherein the resistance element includes two or more of a metal oxide half field effect transistor, a bipolar junction transistor, a semiconductor element and a resistor. The dimmer described in item 8 of the scope of patent application, wherein the dynamic load includes a transistor, a resistor and an operational amplifier, the drain of the transistor and the positive pole of the output terminal of the converter and the main load The anode is connected, the gate of the transistor is connected to the output terminal of the operational amplifier, the source of the transistor is connected to one end of the resistor and the reverse input terminal of the operational amplifier, and the other end of the resistor is connected to the converter's The negative terminal of the output terminal is connected with the negative terminal of the main load, and the control voltage input terminal is connected with the non-inverting input terminal of the controller and the operational amplifier. The dimmer described in claim 11, wherein the first branch current is equal to the control voltage divided by the resistance value of the resistor. The dimmer described in item 8 of the scope of patent application, wherein the converter is a buck converter, a boost converter or a buck-boost converter. The dimmer described in item 8 of the scope of patent application, wherein the controller is a microcontroller or a processor. A controller includes: a detection circuit connected to a converter to detect an output current of the converter, a first branch current of the output current flows through a dimming circuit, and the output current is A second branch current flows through a main load; and a control circuit is connected to the detection circuit and a control voltage input end of the dimming circuit, and receives a control command; Wherein, the control circuit adjusts a control voltage input to the control voltage input terminal according to the control command and the output current, so that the first branch current is adjusted through the control voltage to change the second branch current. The controller described in item 15 of the scope of patent application, wherein the dynamic load includes a resistive element and an operational amplifier, and the first end of the resistive element is connected to the positive pole of the output terminal of the converter and the positive pole of the main load, The second end of the resistance element is connected to the output end of the operational amplifier, the third end of the resistance element is connected to the reverse input end of the operational amplifier, and the fourth end of the resistance element is connected to the negative electrode of the output end of the converter It is connected to the negative pole of the main load, and the control voltage input terminal is connected to the non-inverting input terminal of the control circuit and the operational amplifier. The controller described in claim 16, wherein the resistance element includes two or more of a metal oxide half field effect transistor, a bipolar junction transistor, a semiconductor element and a resistor. The controller described in item 15 of the scope of patent application, wherein the dynamic load includes a transistor, a resistor and an operational amplifier, the drain of the transistor and the positive pole of the output terminal of the converter and the positive pole of the main load Connected, the gate of the transistor is connected to the output of the operational amplifier, the source of the transistor is connected to one end of the resistor and the inverting input of the operational amplifier, and the other end of the resistor is connected to the output of the converter The negative terminal of the terminal is connected to the negative terminal of the main load, and the control voltage input terminal is connected to the non-inverting input terminal of the control circuit and the operational amplifier. The controller described in item 18 of the scope of patent application, wherein the first branch current is equal to the control voltage divided by the resistance value of the resistor. The controller described in item 15 of the scope of patent application, wherein the converter is a buck converter, a boost converter or a buck-boost converter, and the controller is a microcontroller or a processor.

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