JP3158700U - LED dimming device, circuit and dimming system - Google Patents

Abstract

An LED capable of using an LED light source instead of an incandescent lamp by inserting a conventional dimmer for an incandescent lamp and an LED dimmer in series between an AC power source and an LED light source device Provide a dimming system. A dimming device for an incandescent lamp is combined with a rectifier circuit, an automatic matching circuit, an analog-digital conversion circuit, and a pulse width modulation circuit to adjust the brightness of the LED light source device. An optical device is configured. The dimmer for the incandescent lamp generates a dimming signal. The matching circuit is connected to the dimmer, receives the dimming signal, performs full-wave rectification, and converts it to a matching signal having the lowest output current. The analog-digital conversion circuit is connected to the matching circuit, receives the matching signal, and converts it into a converted signal having a positive half-cycle sine wave. The pulse width modulation circuit is connected to the analog-digital conversion circuit, receives the conversion signal, and generates a pulse width modulation signal having a stable output current. Finally, the LED light source device is connected to the LED dimming device and can receive the pulse width modulation signal to adjust the brightness. [Selection] Figure 5

Description

  The present invention relates to a light control device, and more particularly to a light control device for an LED light source.

  As science and technology advance and energy saving and power saving become popular, various lighting fixtures and various new light sources are constantly evolving, for example, from conventional incandescent bulbs to the latest white LED bulbs. As the application range of these light sources expands, such as stage lighting and home lighting, various dimming devices that can adjust the level of light and darkness of light beams are also widely used. Yes. However, since the driving methods of various different light sources are different, these light control devices must be improved in order to be applied to various light sources.

  Conventional light sources such as incandescent light sources generally have a service life of over 1000 hours and are currently the most widely used light sources. This type of conventional light source is often used in household and commercial lighting. A new type of light source such as an LED (Light Emitting Diode) light source has an advantage that it has a long service life of 100,000 hours or more, can save power, and has a short reaction time. With the trend of energy saving and carbon dioxide reduction, LED light sources are also gaining popularity among the general public.

  FIG. 1 is a schematic view of a module of a light control device of a conventional light source device. The conventional light control device 1 mainly adjusts the light source luminance with respect to the conventional light source device 12, and the conventional light source device 12 generally uses an incandescent light source as its light source. The conventional light source device 12 can drive light emission by directly using an AC signal such as an AC power supply (AC power supply signal). Therefore, if a dimmer 11 is further installed between the AC power supply 10 and the conventional light source device 12, the light source luminance can be adjusted with respect to the conventional light source device 12 using the dimmer 11. Become.

  Generally speaking, the dimmer 11 can be a TRIAC (TRI for for Alternate Current) or SCR (Silicon Controlled Rectifier), and adjusts the magnitude, voltage, or phase of the input AC power supply. Thus, the purpose of adjusting the light emission luminance of the conventional light source device 12 can be achieved. Since the conventional light source device 12 is driven by directly using an AC signal, the signal output from the dimmer 11 is also an AC signal.

  FIG. 2 is a schematic view of a module of a light control device of a conventional LED light source device. The LED light source device 24 is a device using a light emitting diode (LED) as its light source. Since an LED light source can drive light emission only by a DC power source, it cannot drive light emission by directly using an AC power source (AC power source signal) like a conventional light source. Accordingly, an analog-digital conversion circuit 21 is further provided between the AC power source 10 and the LED light source device 24 so that the AC power source signal is converted into a DC power source signal so that the LED light source device 24 can be driven smoothly. Become. However, conversion circuits that are currently on the market, such as ballasts for incandescent light bulbs, do not have a power signal conversion function, and the general public directly converts incandescent light sources, which are conventional light sources, into new LED light sources. It cannot be switched.

  Further, simply driving the light emission of the LED light source device 24 cannot completely satisfy the user's demand. Therefore, a dimming function is provided in order to meet the user's demand for use at home or on the stage. It is necessary to add more. A conventional LED dimming circuit 25 is further connected to the rear (right) end of the dimmer 11 shown in FIG. 1, as shown in FIG. 24 can be dimmed. The conventional LED dimming device 2 can be configured by combining the conventional LED dimming circuit 25 and the dimmer 11, and the conventional LED dimming circuit 25 is an analog-digital (AC-DC) conversion. The circuit 21 includes a pulse width modulation circuit 22 and a pulse width modulation signal control circuit 23.

  The dimmer 11 of the conventional LED dimmer 2 is connected to the AC power supply 10, receives the AC power supply signal of the AC power supply 10, adjusts the current, voltage, or phase of the AC power supply 10, and outputs the dimming signal. Form. The analog-digital conversion circuit 21 is connected to the dimmer 11, receives the dimming signal from the dimmer 11, performs alternating current and direct current conversion, and forms a direct current conversion signal. The pulse width modulation circuit 22 is connected to the analog-digital conversion circuit 21 and the pulse width modulation signal control circuit 23, and receives the conversion signal of the analog-digital conversion circuit 21 and the pulse width modulation control signal of the pulse width modulation signal control circuit 23. Thus, a pulse width modulation signal is formed. Finally, the conventional LED light source device 24 is connected to the pulse width modulation circuit 22 and receives the pulse width modulation signal to drive the light emission of the LED light source device 24. The pulse width modulation circuit 22 is generally a DC-DC conversion pulse width modulation circuit 22, which receives a DC conversion signal to obtain a reference voltage level of the conversion signal output, and a pulse width modulation signal control circuit 23. The pulse width modulation control signal is received and used as a reference operation cycle for conversion signal output.

  FIG. 3 is a schematic diagram of signals in a light control device of a conventional LED light source device. Normally, the AC power supply signal of the AC power supply 10 is a sine wave or a cosine wave. Here, a sine wave will be described as an example. As shown in FIGS. 2 and 3, the dimmer 11 receives the AC power supply signal of the AC power supply 10, and the user can generate the dimming signal by adjusting the dimmer 11. Generally speaking, the dimmer 11 can be divided into types such as voltage adjustment, current adjustment, or phase adjustment of the AC power supply signal. Here, the dimmer 11 that adjusts the phase is taken as an example. To. The dimming signal that the dimmer 11 receives and generates the AC power supply signal of the AC power supply 10 is a sine wave waveform in which the 1/4 cycle is a positive half cycle and a negative half cycle. The analog-digital conversion circuit 21 receives this dimming signal, and generates a conversion signal having a DC voltage after the rectification, transformation, and regulator of the analog-digital conversion circuit 21. The pulse width modulation circuit 22 receives this conversion signal and combines the pulse width modulation control signal transmitted from the pulse width modulation signal control circuit 23 to generate a pulse width modulation signal. The LED light source device 24 receives this pulse width modulation signal and drives the light emission of the LED light source. The pulse width modulation circuit 22 can adjust the light emission luminance of the LED light source device 24 by adjusting the voltage level or the duty cycle of the pulse width modulation signal.

  In the conventional LED light source device 24, the conventional LED dimming device 2 can be formed by combining the dimmer 11 that is generally well seen with the conventional dimming circuit 25, and generates a pulse width modulation signal. Thus, the LED light source device 24 can be driven. However, if the conduction angle adjusted by the user with respect to the dimmer 11 is too small, the current value of the dimming signal generated from the dimmer 11 of a different manufacturer brand or different standard becomes too small. When the digital conversion circuit 21 receives a dimming signal lower than the critical value of the operating current, the conversion signal output from the analog-digital conversion circuit 21 becomes unstable. Alternatively, when the current value of the conversion signal received by the pulse width modulation circuit 22 is lower than the critical value of the operating current of the pulse width modulation circuit 22, the pulse width modulation signal output from the pulse width modulation circuit 22 becomes an irregular signal. Become. This irregular conversion signal or pulse width modulation signal causes a situation in which the LED light source device 24 blinks or cannot be lit. In addition, the conventional DC-DC conversion pulse width modulation circuit 22 does not have a transformer conversion coil and thus does not have an isolation effect, and the conventional LED light source device 24 is likely to have a leakage problem.

  An object of the present invention is to provide an LED dimming device capable of dimming an LED light source device by using a conventional dimmer and the LED dimming device of the present invention and promoting industrial improvement. There is.

An LED dimming device provided by an embodiment of the present invention is connected to an AC power source, receives an AC power signal, and generates a dimming signal based on the AC power signal (dimming angle);
A rectifier circuit connected to the dimmer, receiving the dimming signal, rectifying the dimming signal and generating a rectified signal;
The matching signal is connected to the dimmer, receives the rectified signal, generates a matching signal based on the rectified signal, the matching signal has the same waveform as the rectified signal, and the matching signal has a minimum output current value A matching circuit in which the minimum output current value is an output current value of a conduction angle greater than 0 degrees;
An analog-to-digital conversion circuit connected to the matching circuit, receiving the matching signal, performing signal conversion on the matching signal, and forming a converted signal having a positive half-cycle sine wave;
Connected to the analog-digital conversion circuit, receives the conversion signal, generates a pulse width modulation signal based on the conversion signal, and transmits the pulse width modulation signal to the LED light source device to emit light from the LED light source device. And a pulse width modulation circuit to be driven.

An LED dimming device provided by an embodiment of the present invention is a dimmer that is connected to an AC power source, receives an AC power signal, and generates a dimming signal based on a dimming angle (AC power signal);
An LED dimming device including an LED dimming circuit connected to the dimmer and generating a pulse width modulation signal based on the dimming signal,
The LED dimming device is connected to the LED dimming circuit, drives an LED light source based on the pulse width modulation signal,
The LED dimming circuit is
Connected to the dimmer, receives the dimming signal of the dimmer, converts the dimming signal into a matching signal, and the matching signal has a minimum output current value, and the minimum output current value Is a matching circuit that is fixed to an output current value with a conduction angle greater than 0 degrees;
An analog-to-digital conversion circuit connected to the matching circuit, receiving the matching signal, converting the matching signal, and forming a converted signal having a positive half-cycle sinusoidal waveform;
A pulse width modulation circuit connected to the analog-digital conversion circuit, receiving the conversion signal, and generating a pulse width modulation signal based on the conversion signal.

  The LED dimming circuit of the present invention can solve the above-described problems, such as avoiding leakage of the LED light source device.

It is the schematic of the module of the light control apparatus of the conventional light source device. It is the schematic of the module of the light control apparatus of the conventional LED light source device. It is the schematic of the signal of the light control apparatus of the conventional LED light source device. It is the schematic of the system module of the LED light control apparatus of Example 1 of this invention. It is the schematic of the signal of the LED light control apparatus of Example 1 of this invention. It is the schematic of the system module of the LED light control apparatus of Example 2 of this invention. It is the schematic of the signal of the LED light control apparatus of Example 2 of this invention.

  In order that the features and technical contents of the present invention may be further understood, a detailed description of the present invention will be given below with reference to the accompanying drawings.

  FIG. 4 is a schematic diagram of a system module of the LED light control device according to the first embodiment of the present invention. The LED dimmer 3 includes a dimmer 11, a rectifier circuit 41, an automatic matching circuit (matching circuit) 42, an analog-digital (AC-DC) conversion circuit 21, and a pulse width modulation circuit 43.

  The dimmer 11 is connected to the AC power supply 10 and receives an AC power supply signal, adjusts the current, voltage, or phase of the AC power supply signal of the AC power supply 10 to form a dimming signal. In this embodiment, the dimmer 11 that changes the phase of the AC power supply signal is taken as an example. The rectifier circuit 41 is connected to the dimmer 11 to receive the dimming signal, rectifies the dimming signal, and generates a rectified signal.

  The automatic matching circuit 42 is connected to the rectifier circuit 41, receives the rectified signal, performs signal matching with the rectified signal, and generates a matching signal. The analog-digital conversion circuit 21 is connected to the matching circuit 42, receives the matching signal, performs AC / DC conversion, and forms a DC conversion signal.

  The pulse width modulation circuit 43 is connected to the analog-digital conversion circuit 21 and receives the conversion signal of the analog-digital conversion circuit 21, and forms a pulse width modulation signal based on the voltage level and the operation cycle of the conversion signal. Finally, the LED dimming device 3 drives the LED light source device 24 by generating this pulse width modulation signal.

  Since the rectifier circuit 41 can be integrated with the dimmer 11 or the matching circuit 42, the matching circuit 42 can receive the rectified dimming signal, It is also possible to directly receive and rectify within the matching circuit 42. The rectifier circuit 41, the matching circuit 42, the analog-digital conversion circuit 21, and the pulse width modulation circuit 43 can be combined to form the LED dimming circuit 40. Alternatively, the dimmer 11 can be a TRIAC or SCR dimmer.

  The dimmer 11 is a conventional dimmer, which has different standards from many manufacturer brands, and the dimming signals generated from the different conduction angles of the various dimmers 11 and their output current values are all the same. Not necessarily. Therefore, since the dimmer 11 cannot generate a dimming signal having the same standard, the conventional LED dimming circuit 25 shown in FIG. Unless the signal is adjusted, the LED light source device 24 cannot be adjusted well.

  In contrast, the first embodiment of the present invention uses the automatic matching circuit 42 to perform full-wave rectification on the dimming signal based on the change of the dimming signal of the dimmer 11. Furthermore, when the dimmer 11 has a relatively low conduction angle, for example, when the conduction angle is lower than 20 degrees, the matching circuit 42 fixes the output current. For example, by fixing the output current value when the conduction angle is 20 degrees, the matching signal can have the lowest output current value. Thereby, the analog-digital conversion circuit 21 or the pulse width modulation circuit 43 receives the matching signal having the minimum operating current, and the analog-digital conversion circuit 21 or the pulse width modulation circuit 43 can be kept in a normal operation state. It becomes like this. The matching circuit 42 can automatically adjust the output current value of the dimming signal generated from all kinds of dimmers 11, so that the dimmer 11 of any manufacturer brand or any standard can be used. Can be applied.

  The automatic matching circuit 42 can be any type of matching circuit. The automatic matching circuit 42 mainly performs dimming by adjusting and adjusting the dimming signal using a combination of a voltage unit (not shown), a control unit (not shown), and a current unit (not shown). The device 11 can output a matching signal having the lowest operating current in all phases and all operating voltages, and the analog-digital conversion circuit 21 and the pulse width modulation circuit 43 connected to the matching circuit 42 operate normally. It can be carried out. Thereby, the LED light source device 24 can adjust the brightness | luminance normally.

  In addition, in the first embodiment of the present invention, the pulse width modulation circuit 43 of the LED dimming circuit 40 is an AC / DC pulse width modulation circuit 43, which uses a conversion signal generated from the analog-digital conversion circuit 21. A corresponding pulse width modulated signal can be generated. That is, the pulse width modulation circuit 43 sets the period of the conversion signal as the reference operation period of the pulse width modulation signal, and sets the waveform change of the conversion signal as the reference output voltage of the pulse width modulation signal. Further, this type of AC-DC conversion pulse width modulation circuit 43 includes a transformer coil circuit, and thus has an isolation function. That is, the change in the signal at the front end of the pulse width modulation circuit 43 and the pulse width modulation signal generated from the rear end have an isolation effect, so that the LED light source device 24 can be prevented from leaking current.

  It should be noted that in the first embodiment of the present invention, the pulse width modulation signal output from the pulse width modulation circuit 43 of the LED dimming circuit 40 is a pulse width modulation signal having a high voltage and a predetermined current. is there. Since the output voltage of the pulse width modulation signal is higher than the drive voltage of the LED light source device 24, the LED light emitting diode of the LED light source device 24 can be completely activated. Moreover, since the pulse width modulation signal outputs a predetermined current, the LED light emitting diode of the LED light source device 24 can have a stable emission spectrum. Therefore, the light control device 40 according to the first embodiment of the present invention has a function of stably driving the LED light source device 24 and can avoid drift of the emission spectrum of the LED light source due to unstable current.

  FIG. 5 is a schematic diagram of signals of the LED dimming device according to the first embodiment of the present invention. The AC power supply signal of the AC power supply 10 is generally a sine wave or cosine wave, and in this embodiment, a sine wave is taken as an example. Further, the dimmer 11 of the present embodiment takes the dimmer 11 for phase adjustment as an example.

  As shown in FIGS. 4 and 5, the dimmer 11 is connected to the AC power supply 10, receives the AC power supply signal, adjusts the phase of the AC power supply signal, and the quarter cycle is positive. A dimming signal having a sinusoidal waveform in a half cycle and a negative half cycle is generated. The rectifier circuit 41 is connected to the dimmer 11, receives the dimming signal, rectifies the signal, converts the negative half-cycle signal into a positive half-cycle signal, and generates a rectified signal.

  The automatic matching circuit 42 is connected to the rectifier circuit 41, receives the rectified signal, performs full-wave rectification, and generates a waveform having a positive half-cycle sine wave. This matching signal has the same operating frequency and the same maximum voltage output level as the rectified signal. In addition, this matching signal has the lowest output current value. For example, when the dimmer 11 is adjusted to a conduction angle lower than 20 degrees, the output current value is fixed to the current value of the conduction angle of 20 degrees, so that the analog-digital conversion circuit 21 and the pulse width modulation at the rear end are fixed. It can be ensured that the circuit 43 receives the matching signal or the conversion signal having the lowest operating current value. The minimum output current value is higher than the minimum operating current value of the analog-digital conversion circuit 21 or the pulse width modulation circuit 43.

  The analog-digital conversion circuit 21 is connected to the automatic matching circuit 42, receives the matching signal, and a half cycle is a positive half by a transformer element (not shown) and a rectifier element (not shown) inside. A conversion signal having a sine wave waveform with a period is output. The conversion signal and the matching signal have the same operating period and the same maximum output voltage level. The pulse width modulation circuit 43 is connected to the analog-digital conversion circuit 21 to receive the conversion signal, and generates a pulse width modulation signal based on the maximum output voltage level and the operation cycle of the conversion signal. This pulse width modulation signal has a high voltage and a predetermined output current. The high voltage is higher than the operating voltage of the LED light source device 24, and the predetermined output current stabilizes the emission chromaticity generated from the LED light source device 24, and the emission spectrum drift of the LED light source device 24 can be avoided.

  Therefore, in the LED dimming device 3 according to the first embodiment of the present invention, when the dimmer 11 has the maximum conduction angle, the dimming signal of the dimmer 11 has a complete sine wave waveform. The rectifier circuit 41 generates a rectified signal by converting the negative half cycle of the dimming signal into a positive half cycle. The matching circuit 42 and the analog-digital conversion circuit 21 generate a matching signal and a conversion signal having the same waveform as the dimming signal, and finally the waveform of the pulse width modulation signal output from the pulse width modulation circuit 43 is a DC output voltage. Get closer. On the contrary, if the conduction angle of the dimming signal output from the dimmer 11 is reduced, the ratio of the sine wave waveform in the dimming signal waveform of FIG. The ratio of the operation period of the conversion signal is also reduced accordingly, and the ratio of the operation period of the pulse width modulation signal is also reduced. The matching signal and the conversion signal maintain a sinusoidal waveform in which a half cycle is a positive half cycle.

  FIG. 6 is a schematic diagram of a system module of the LED light control device according to the second embodiment of the present invention. FIG. 7 is a schematic diagram of signals of the LED dimming device according to the second embodiment of the present invention. The LED dimming device 4 according to the second embodiment of the present invention is almost the same as the LED dimming device 3 in FIG. 4 in the main elements and the connection relationship thereof, but the LED dimming device 4 includes a pulse width modulation circuit 43 and A predetermined current drive circuit (constant current drive circuit) 61 connected to the LED light source device 24 is further included. That is, the LED dimming circuit 60 includes a rectifier circuit 41, a matching circuit 42, an analog-digital conversion circuit 21, a pulse width modulation circuit 43, and a predetermined current drive circuit 61.

  The predetermined current drive circuit 61 is a circuit that can output a predetermined current, and can adjust the output current value of the predetermined current drive signal in FIG. 7 based on the pulse width modulation signal of the pulse width modulation circuit 43. it can. When the operation cycle ratio of the pulse width modulation signal is high, the predetermined current drive circuit 61 outputs a predetermined current drive signal having a relatively high output current value, and when the operation cycle ratio of the pulse width modulation signal is low, the predetermined current drive circuit 61 61 outputs a predetermined current drive signal having a relatively low output current value. Therefore, the predetermined current drive circuit 61 can output different current values based on the operation cycle ratio of the pulse width modulation signal, and the LED light source device 24 can emit the light emission luminance based on the different output current values of the predetermined current drive signal. Will be able to adjust. The predetermined current drive signal in FIG. 7 output from the predetermined current drive circuit 61 is a signal having a predetermined current and a high voltage. In addition, since the high voltage of the predetermined current drive signal is higher than the operating voltage of the LED light source device 24, the emission spectrum drift of the LED light source device 24 can be avoided. Further, it is possible to avoid the problem of blinking due to the switching of the pulse width modulation signal of the pulse width modulation circuit 43.

  The LED dimming device 4 according to the second embodiment of the present invention is particularly applied to the LED light source device 24 that provides a short-distance light source such as a desk lamp, and the pulse width modulation signal of the pulse width modulation circuit 43 is thereby applied. Flashing due to the cause can be avoided, and the discomfort of the eyes due to the flashing of the LED light source when the user uses this light source is eliminated.

  The above-described embodiments are merely for explaining the technical idea and features of the present invention, and are intended to allow those skilled in the art to understand and implement the present invention. It does not limit the patent scope. Accordingly, improvements or modifications having various similar effects without departing from the spirit of the present invention shall be included in the following claims.

DESCRIPTION OF SYMBOLS 1 Conventional light control device 2 Conventional LED light control device 3, 4 LED light control device 10 AC power supply 11 Light control device 12 Conventional light source device 21 Analog-digital (AC-DC) conversion circuit 22, 43 Pulse width modulation circuit 23 Pulse width modulation signal control circuit 24 LED light source device 25 Conventional LED dimming circuit 40, 60 LED dimming circuit 41 Rectifier circuit 42 Matching circuit 61 Predetermined current driving circuit (constant current driving circuit)

Claims (5)

A dimmer connected to an AC power source, receiving an AC power signal and generating a dimming signal based on the AC power signal;
A rectifier circuit connected to the dimmer, receiving the dimming signal, rectifying the dimming signal and generating a rectified signal;
Connected to the rectifier circuit, receives the rectified signal, matches the signal to the rectified signal to generate a matched signal, the matched signal has the same waveform as the rectified signal, and the matched signal is A matching circuit having a minimum output current value, wherein the minimum output current value is an output current value of a conduction angle greater than 0 degrees;
An analog-to-digital conversion circuit connected to the matching circuit, receiving the matching signal, performing signal conversion on the matching signal, and forming a converted signal having a positive half-cycle sine wave;
Connected to the analog-digital conversion circuit, receives the conversion signal, generates a pulse width modulation signal based on the conversion signal, and transmits the pulse width modulation signal to the LED light source device to emit light from the LED light source device. And a pulse width modulation circuit to be driven.   The matching circuit performs full-wave rectification on the rectified signal to generate the matching signal, and the matching signal has the same operation cycle and the same maximum output voltage level as the rectified signal, and the minimum output current value Is higher than the minimum operating current value of the analog-to-digital conversion circuit or the pulse width modulation circuit, the conversion signal has the same operating period and the same maximum output voltage level as the matching signal, and the pulse width modulation signal is The LED light control device according to claim 1, wherein the LED light control device has an output voltage level higher than a drive voltage of the LED light source device and a predetermined output current value. Furthermore, a predetermined current driving circuit connected to the pulse width modulation circuit and the LED light source device,
The predetermined current drive circuit receives the pulse width modulation signal, outputs a predetermined current drive signal, drives the LED light source device, and based on the operation cycle proportion of the pulse width modulation signal, the predetermined current drive signal The LED light control device according to claim 1, wherein the current value of the LED is adjusted. Connected to a dimmer, receives the dimming signal of the dimmer and converts the dimming signal into a matching signal, the matching signal has a minimum output current value, and the minimum output current value is 0 degrees A matching circuit fixed to an output current value of a larger conduction angle;
An analog-to-digital conversion circuit connected to the matching circuit, receiving the matching signal, performing signal conversion on the matching signal, and forming a converted signal having a positive half-cycle sine wave;
An LED dimming circuit comprising: a pulse width modulation circuit connected to the analog-digital conversion circuit, receiving the conversion signal and generating a pulse width modulation signal based on the conversion signal. A dimmer that is connected to an AC power supply, receives an AC power supply signal, and generates a dimming signal based on a dimming angle;
An LED dimming device including an LED dimming circuit connected to the dimmer and generating a pulse width modulation signal based on the dimming signal;
The LED dimming device is connected to the LED dimming circuit, drives an LED light source based on the pulse width modulation signal,
The LED dimming circuit is
Connected to the dimmer, receives the dimming signal of the dimmer, converts the dimming signal into a matching signal, and the matching signal has a minimum output current value, and the minimum output current A matching circuit whose value is fixed to an output current value of a conduction angle greater than 0 degrees;
An analog-to-digital conversion circuit connected to the matching circuit, receiving the matching signal, converting the matching signal, and forming a converted signal having a positive half-cycle sinusoidal waveform;
An LED dimming device comprising: a pulse width modulation circuit connected to the analog-digital conversion circuit, receiving the conversion signal, and generating the pulse width modulation signal based on the conversion signal.

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