JP6923141B1 - PWM conversion circuit, PWM conversion method and LED dimming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PWM conversion circuit, a PWM conversion method and an LED dimming system capable of stably converting a phase control output from a phase control type dimming unit into a PWM control output. A PWM conversion circuit 3 in which a phase control output from a phase control type dimming unit 2 is input and the input phase control output is converted into a PWM control output, corresponding to the phase control output. It has a pulse waveform generation unit 30 that generates a DC pulse waveform, and a measurement unit that counts and measures the presence or absence of the pulse waveform by a measurement sampling signal over a fixed unit count time. A control processing means 6 for outputting a PWM control signal having a pulse width corresponding to the measurement result is provided based on the measurement result of the above. [Selection diagram] Fig. 1

Description

The present invention relates to a PWM conversion circuit that converts a phase control output from a phase control type dimming unit into a PWM (Pulse Width Modulation) control output, a PWM conversion method, and an LED (Light Emitting Diode) dimming system.

In the field of dimming of lighting, a phase control type dimmer that dims by applying an AC voltage to an incandescent light bulb or a halogen light bulb by a phase control method is widely used.

On the other hand, with the recent increase in the output of LEDs, lighting fixtures used indoors or outdoors using LEDs having low power consumption and long life as a light source have been developed and become widespread. Since the LED is a semiconductor that is lit by direct current, it cannot be lit directly by alternating current, and it is difficult to illuminate the LED by using a phase control type dimmer.
Therefore, in order to easily control the dimming of the LED as a light source, a method of supplying PWM control power to the LED to dimm the light is widely adopted.

By the way, for example, when replacing an incandescent light bulb or a halogen light bulb that has been dimmed with an existing phase control type dimmer with an LED light source, it takes time and effort to replace it with a new PWM signal type dimmer. There is a problem that it costs money.

Under the above circumstances, the applicant has proposed a phase control signal / PWM converter that converts a phase control signal into a PWM signal (see Patent Document 1). What is shown in Patent Document 1 outputs a PWM signal from the additive average value obtained by additively averaging the input voltage measurement over the past four periods, and is affected by the phase shift and noise of the phase control signal. This is to suppress the instability of the PWM signal and prevent the flicker of the light emitted from the LED.

Japanese Unexamined Patent Publication No. 2017-220438 Japanese Unexamined Patent Publication No. 2012-195307 JP-A-2017-76529

However, although Patent Document 1 shows that the arithmetic mean value is used, a specific method for suppressing the instability of the PWM signal is not disclosed.

The present invention has been made in view of the above problems, and provides a PWM conversion circuit, a PWM conversion method, and an LED dimming system capable of stably converting a phase control output from a phase control type dimming unit into a PWM control output. The purpose is.

The PWM conversion circuit according to the embodiment of the present invention is a PWM conversion circuit in which a phase control output from a phase control type dimming unit is input and the input phase control output is converted into a PWM control output. A number of measurement sampling signals are output by the pulse waveform generator that generates a DC pulse waveform corresponding to the output and the measurement sampling signal for the presence or absence of the pulse waveform over a fixed unit count time. It has a measuring unit that counts and measures the presence, and includes a control processing means that outputs a PWM control signal having a pulse width corresponding to the measurement result based on the measurement result of the measuring unit.
The term "output" includes a signal level output for transmitting information and a drive power level output. The meaning of the output is not interpreted in a particularly limited way.

The LED dimming system according to the embodiment of the present invention is connected to the phase control type dimming unit that outputs the phase control output, the PWM conversion circuit connected to the phase control type dimming unit, and the PWM conversion circuit. It is equipped with an LED lighting fixture.

Further, the PWM conversion method according to the embodiment of the present invention includes a PWM conversion circuit in which a phase control output from a phase control type dimming unit is input and the input phase control output is converted into a PWM control output. The step of generating a DC pulse-like waveform corresponding to the control output and the presence or absence of the pulse-like waveform are repeated for how many measurement sampling signals are output by the measurement sampling signal over a certain unit count time. Between the step in the step of repeatedly outputting the PWM control signal, which includes a step of counting and measuring and a step of repeatedly outputting a PWM control signal having a pulse width corresponding to the measurement result based on the measurement result. It is characterized in that a step of relaxing and interpolating a change in the pulse width of the PWM control signal is provided.

According to the embodiment of the present invention, it is possible to provide a PWM conversion circuit, a PWM conversion method, and an LED dimming system capable of stably converting a phase control output from a phase control type dimming unit into a PWM control output.

It is a block block diagram which shows the LED dimming system which concerns on 1st Embodiment of this invention. It is a timing chart which shows the process of converting a phase-controlled waveform into a PWM control signal. It is a graph which shows the relationship between the measured value (count value) and the duty ratio (dimming ratio) of a PWM control signal. It is a flowchart which shows the measurement operation. It is a timing chart explaining the generation state of the PWM control signal when noise or flutter occurs in a phase control output. It is a graph which shows the relationship between the measured value (count value) and the duty ratio (dimming ratio) of a PWM control signal. It is explanatory drawing which shows the interpolation method of a PWM control signal. It is a graph which shows the relationship between the measured value (count value) and the duty ratio (dimming ratio) of a PWM control signal in a plurality of types of phase control type dimmers having different output ranges. It is a timing chart which shows another example of the generation method of a PWM control signal. It is a block block diagram which shows the LED dimming system which concerns on 2nd Embodiment (Example 1) of this invention. It is a block block diagram which shows the LED dimming system which concerns on the 2nd Embodiment (Example 2).

Hereinafter, the PWM conversion circuit, the PWM conversion method, and the LED dimming system according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 9. The PWM conversion circuit of the present embodiment converts the phase control signal from the phase control type dimming unit into a PWM control signal, supplies PWM control power to the lighting means (LED lighting fixture), and controls the lighting means by dimming. Is what you do.

FIG. 1 is a block configuration diagram showing an LED dimming system. As shown in FIG. 1, the LED dimming system 1 includes a phase control dimmer 2 as a phase control dimming unit, a PWM converter 3 as a PWM conversion circuit, and lighting means using an LED as a light source. The LED lighting fixture 4 and the DC power supply unit 5 are provided.

The phase control type dimmer 2 is an existing dimmer by a commercially available phase control method, and is connected to a commercial AC power supply AC to change the conduction angle of the AC voltage to generate an incandescent light bulb or a halogen light bulb by the phase control output. It is dimmable. The phase control type dimmer 2 has a body having a substantially rectangular shape on the front side, and is a wall-embedded type that is embedded in a wall surface and mounted. 21, ON / OFF switch 22 and indicator lamp 23 are provided. Rotation operation The dimming degree can be adjusted by rotating the knob 21.

The rotation operation knob 21 for dimming may be a slide type. The special operation method is not limited. Further, the phase control type dimmer 2 may be of an antiphase type.

The PWM converter 3 has a box-shaped main body, and the insulating step-down section 31, the rectifying section 32, the noise removing section 33, the control processing means 6, and the drive circuit section 34 are provided in the main body. ing.

The insulation step-down unit 31 is an isolation transformer, and drops the input voltage from the commercial AC power supply AC to, for example, about 5V. As a result, the handling of the signal inside the PWM converter 3 can be simplified, and the electrical safety can be ensured by insulating the signal.

A rectifying unit 32 is connected to the insulating step-down unit 31. The rectifying unit 32 is a full-wave rectifying circuit composed of a bridge diode, and rectifies an AC input signal from the isolated step-down unit 31 to direct current.

A noise removing unit 33 is connected to the rectifying unit 32. Specifically, the noise removing unit 33 is a photocoupler including a light emitting diode and a phototransistor. The signal rectified to direct current from the rectifying unit 32 is input to the noise removing unit 33. The input signal from the rectifying unit 32 may include noise components and waveform disturbances, and if the measurement is performed as it is, the noise components and the like may be erroneously determined as the signal to be measured, and an operation abnormality may occur. Therefore, a minute noise component that cannot drive the photocoupler is removed, and the waveform is stabilized.

Such an insulating step-down unit 31, a rectifying unit 32, and a noise removing unit 33 constitute a pulse-shaped waveform generating unit 30 that generates a DC pulse-shaped waveform. The pulse waveform generation unit 30 generates an output waveform corresponding to the phase control output from the phase control dimmer 3, and the elements constituting the special pulse waveform generation unit 30 are limited. is not it.

A control processing means 6 is connected to the noise removing unit 33. As the control processing means 6, a microcomputer (hereinafter, referred to as “microcomputer”) that executes overall control by software is used.

The microcomputer which is the control processing means 6 is roughly composed of a CPU 61 having a calculation unit, a processing unit, a determination unit, a control unit and a counting unit, ROM 62 and RAM 63 which are storage means, and input / output control means. ing. The microcomputer calculates and processes the input signal from the noise removing unit 33 corresponding to the phase control output, converts it into a PWM control signal, and outputs it to the drive circuit unit 34.

A drive circuit unit 34, a setting change unit 64, a discrimination switch 65, and a selection switch 66 are connected to the input / output control means of the control processing means 6. The setting change unit 64 includes a jumper wire, and by switching the connection, the PWM control signal is subjected to gamma correction processing according to the characteristics of the LED of the LED lighting fixture 4, and the PWM control signal is output as a linear output. It can be selectively switched to a logarithmic output. The discrimination switch 65 can switch the PWM control signal between positive logic and negative logic according to the type of the LED lighting fixture 4 by its operation.

Since the output range of the selection switch 66 differs depending on the phase control type dimmer 2 to be applied, as will be described in detail later, the output range of the phase control type dimmer 2 and the output on the PWM converter 3 side Used for consistency.

The drive circuit unit 34 has a power amplification function, receives a DC output from the DC power supply unit 5, receives a PWM control signal output from the control processing means 6, and receives an LED lighting fixture in response to the PWM control signal. The lighting of the LED of 4 is controlled. The drive circuit unit 34 has a switching element such as an FET, and the switching element is turned ON / OFF in response to an input of a PWM control signal to control the conduction time ratio (duty ratio) of the current flowing from the drive circuit unit 34 to the LED. And dimming. In this embodiment, 4095 gradation dimming is possible from 100% lighting to about 0% by control by the PWM control signal. The tone can be appropriately selected.

The PWM converter 3 as described above is connected to the phase control dimmer 2 via the load interface unit 7. The load interface unit 7 includes a load device. The load device is, for example, a bleeder resistor connected in parallel to the PWM converter 3. Depending on the phase control type dimmer 2, the PWM converter 3 may not operate normally because it does not have a sufficient capacity. Therefore, a load device having an appropriate resistance value is interposed. A plurality of bleeder resistors may be connected and adjusted.

Further, an LED lighting fixture 4 is connected to the output side of the PWM converter 3. The LED lighting fixture 4 is, for example, a lighting fixture installed in a living room. It has a plurality of LEDs 41 mounted on a substrate as a light source, and irradiates the living room with light emitted from the LEDs 41 whose lighting is controlled by PWM control. As the LED 41, a white LED having a light bulb color, a neutral white color, a daylight color, or the like is used. Further, although a surface mount type (SMD) LED package is used for the LED, a COB (chip on board) type in which the LED is directly mounted on the board may be used, and the mounting method is particularly limited. It is not something that will be done. The LED 41 is not limited to a white light emitting color, and an LED 41 that emits red, green, or blue light can be used.
The DC power supply unit 5 receives, for example, a commercial AC power source to generate a DC output, and supplies electric power to the LED lighting fixture 4 through the drive circuit unit 34.

Next, the operation of the LED dimming system will be described with reference to FIGS. 2 to 9. 2 to 5 show a method of generating a PWM control signal, FIGS. 6 and 7 show an interpolation method of a PWM control signal, and FIG. 8 shows an example of a phase control type dimmer having a different output range. ing. Further, FIG. 9 shows another example in the method of generating the PWM control signal. The operation of the LED dimming system 1 is mainly executed by the software of the control processing means 6.

The LED dimming system 1 converts the phase control signal from the phase control dimmer 2 into a PWM control signal by the PWM converter 3, supplies PWM control power to the LED lighting fixture 4, and causes the LED lighting fixture 4 to operate. Lighting control.
(Method of generating PWM control signal)

A basic method for generating a PWM control signal will be described. FIG. 2 is a timing chart showing the process of converting a phase-controlled waveform into a PWM control signal, and FIG. 3 shows a relationship between a measured value (count value) and a duty ratio (dimming ratio) of the PWM control signal. FIG. 4 is a flowchart showing a measurement operation.

In FIG. 2, FIG. 2A is an output waveform after the phase control input transmitted from the phase control type dimmer 2 is stepped down by the isolation transformer of the isolation step-down unit 31, and is a phase-controlled AC waveform. Is. For example, it shows a state in which the conduction angle changes with the dimming operation and the dimming degree is changed to 50%, 60%, and 70%.
FIG. 2B shows a DC output waveform after being rectified by the bridge diode of the rectifying unit 32.

FIG. 2C shows the state of the input waveform in which the output waveform after rectification is input to the photocoupler of the is-removing unit 33. The operating voltage is set for the photocoupler, and the low voltage part that cannot drive the photocoupler is cut to eliminate the influence of minute noise components, and the output waveform of the photocoupler is DC as shown in FIG. 2 (d). The waveform is stabilized as a pulsed waveform of.

In the present embodiment, the presence or absence of the output waveform shown in FIG. 2D corresponding to the phase control output from the phase control type dimmer 3 is measured. Specifically, the ON (Hight) state in which this output waveform is output is measured by the ON / OFF measurement sampling signal. The measurement sampling signal is a signal output at intervals of 10 μs (microseconds), and the ON state of the output waveform is counted by the measurement sampling signal. That is, it counts according to how many measurement sampling signals are output during the ON state of the output waveform. The measurement method will be described in detail below according to the figure.
<Calculation of cumulative movement 1>

(1) When the initial luminous intensity is 50%, 5000 samples (5000 times) of measurement sampling signals are output in 50 ms (milliseconds). During this 50 ms period, the measurement sampling signal of 2400 samples is output during the ON state of the output waveform, and it is calculated as 2400 counts (count (1)). The count value according to the luminous intensity of the phase control type dimmer 2 at the start time is 2400 counts.

(2) When the next dimming intensity is 60%, the measurement sampling signal of 2900 samples is output during the ON state of the output waveform for 50 ms, and it is calculated as 2900 counts (count (2)). ..

(3) When the count (2) is completed, the count values of 10000 samples (10000 times) in the 100 ms period (“unit count time”) of the count (1) and the count (2) are totaled and calculated as 5300 counts. Determine the total number of movements (total number of movements 1).
(4) A PWM control signal having a pulse width based on a duty ratio of dimming intensity corresponding to 5300 counts of the cumulative movement 1 is output from the control processing means 6.
<Calculation of cumulative movement 2>

(1) When the dimming intensity is 70%, the measurement sampling signal of 3400 samples is output during the period of the ON state of the output waveform for 50 ms, and it is calculated as 3400 counts (count (3)).

(2) When the count (3) is completed, the count values of 10000 samples (10000 times) in the 100 ms period (“unit count time”) of the count (2) and the count (3) during the immediately preceding 50 ms are totaled. Calculate as 6300 counts and determine the total movement (total movement 2).
(3) Then, the PWM control signal of the pulse width according to the duty ratio of the dimming degree corresponding to the total movement of 6300 counts is output from the control processing means 6.
<Calculation of cumulative movement 3>

In the same manner as described above, the count values of 10000 samples (10000 times) in the 100 ms period (“unit count time”) of count (3) and count (4) are totaled and calculated as 7150 counts to determine the total movement (1). The control processing means 6 outputs a PWM control signal of the pulse width according to the duty ratio of the dimming degree corresponding to the total movement 3) and the total movement 7150 counts. After that, the same measurement operation is repeatedly executed.

In the measurement method for generating the PWM control signal as described above, the presence / absence of the pulsed waveform is counted by the measurement sampling signal over a fixed unit count time in the counting unit as the measurement unit of the control processing means 6. Based on the count result of the count unit, the PWM control signal of the pulse width according to the duty ratio of the dimming degree corresponding to the count result is output.

Therefore, the LED dimming system 1 PWMs the phase control signal from the phase control dimmer 2 whose dimming degree is adjusted by rotating the rotation operation knob 21 of the phase control dimmer 2. The converter 3 converts it into a PWM control signal, supplies PWM control power to the LED lighting fixture 4, and controls the lighting of the LED lighting fixture 4. Therefore, it is possible to reduce the influence of noise and the like on the LED lighting fixture 4 and accurately adjust the dimming and control the lighting.

In addition, the unit count time is partially (1/2) duplicated. Specifically, for example, in the calculation of the total movement 2, the period of the count (2) in the calculation of the total movement 1 is set in duplicate, and the count value is used in duplicate as the calculation information. There is. By overlapping the unit count times in this way, it is possible to alleviate the degree of change between the count value of the cumulative movement 1 and the count value of the cumulative movement 2, and suppress the flicker of lighting of the LED lighting fixture 4. can do.

In the present embodiment, the period (100 ms) that is the base for calculating the cumulative movement is set as the "unit count time", and since the measurement operation is repeated, a plurality of unit count times are repeatedly set. ..

Next, the relationship between the cumulative movement count value and the output of the PWM control signal will be described with reference to FIG. FIG. 3 is a graph in which 0 to 10000 samples of the measurement sampling signal are allocated to the output of the PWM control signal from 0 to 100%. The horizontal axis shows the count value of the output waveform in the ON state, and the vertical axis shows the output (duty ratio) of the PWM control signal.

The control processing means 6 has a data table regarding the relationship between the count value of the cumulative movement and the output of the PWM control signal. Therefore, when the count value of the cumulative movement 1 is 5300 counts, the PWM control signal having a pulse width of 53% of the duty ratio is output from the control processing means 6, and when the count value of the cumulative movement 2 is 6300 counts, the duty ratio is 63%. The PWM control signal having a pulse width of 71.5% is output from the control processing means 6, and when the count value of the cumulative movement 3 is 7150 counts, the PWM control signal having a pulse width of 71.5% is output from the control processing means 6. ..

For example, the change from lighting the LED 41 by a PWM control signal having a duty ratio of 53% in the cumulative movement 1 to lighting the LED 41 by a PWM control signal having a duty ratio of 63% in the cumulative movement 2 is changed. , The brightness of the light changes suddenly, which may cause a feeling of flicker. In the present embodiment, in order to eliminate such inconvenience, as described later, when updating from the output by the total movement 1 to the output by the total movement 2 and shifting, the change of the PWM control signal is relaxed and interpolated. The period is set.

Next, the outline of the flow of the method of generating the PWM control signal will be described with reference to FIG. If the PWM control signal of the embodiment can be generated, the content and order of each processing step can be changed.

When the start-up of the LED dimming system 1 is started, the measurement sampling signal is output at intervals of 10 μs (step S1). Next, it is determined whether or not there is a pulsed waveform output from the photocoupler, that is, whether or not it is ON (step S2). When the pulsed waveform is ON, the measurement sampling signal is counted (step S3), and it is determined whether or not 5000 samples of the measurement sampling signal are output during 50 ms (step S4). On the other hand, when the pulse waveform is not ON but OFF in step S2, the determination in step S4 is performed without counting in step S3.

If 5000 samples of the measurement sampling signal are output in step S4, it is determined whether or not the count (1) is the first time (step S5), and if the count (1) is the count value of the count (1). Is stored in the storage means (step S6).

Further, if it is not the first count (1) in step S5, it is determined whether or not it is the second count (2) (step S7), and if it is the count (2), the count (2) is determined. The count value is stored in the storage means (step S8). Next, the count value of the count (2) is added to the count value of the count (1) (count (1) value + count (2) value) to calculate the cumulative movement 1 (step S9). Subsequently, the total movement 1 is determined (step S10), and the PWM control signal corresponding to the total movement 1 is output (step S11).

Similarly, if it is not the second count (2) in step S7, it is determined whether or not it is the third count (3) (step S12), and if it is the count (3), the count (3). The count value of is stored in the storage means (step S13). The count value of the count (3) is added to the count value of the count (2) (count (2) value + count (3) value) to calculate the cumulative movement 2 (step S14). The total movement 2 is determined (step S15), and the PWM control signal corresponding to the total movement 2 is output (step S16). After that, the same steps are repeatedly executed.

Next, a schematic PWM control signal generation state when noise or fluttering occurs in the phase control output will be described with reference to FIG. FIG. 5 is a timing chart corresponding to FIG. 2, and the description overlapping with FIG. 2 will be omitted.

As shown in FIG. 5A, the AC waveform of the phase-controlled output is changed to, for example, 50%, 48%, 52%, 45%, 55% of the dimming intensity as the output by changing the conduction angle. ing. The average output during this period is 50%. Here, noise is generated in the waveform of the initial output of 50%.

However, the operating voltage of the photocoupler is set, the low voltage part that cannot drive the photocoupler is cut, and only the high voltage part is taken out, and the output waveform of the photocoupler is a direct current as shown in FIG. 5 (d). It is output as a stable pulsed waveform.

Therefore, during the ON state of the pulsed waveform, the measurement sampling signal of 2400 samples is output, and the count value is calculated to be 2400 counts. Therefore, even when noise or fluttering occurs, the count value is the same as when the output is 50% without noise, and the output becomes 50% and stabilizes.
(Interpolation method of PWM control signal)

A method of interpolating the PWM control signal will be described with reference to FIGS. 6 and 7. FIG. 6 is a graph in which 0 to 10000 samples of the measurement sampling signal are allocated to the output of the PWM control signal from 0 to 100%. The horizontal axis shows the count value of the output waveform in the ON state, and the vertical axis shows the output (duty ratio) of the PWM control signal. In this example, the case where the count value of the start value is 2400 counts and the count value of the cumulative movement 1 is 5400 counts is illustrated.

In this case, the output of the PWM control signal is updated and changed from 24% to 54%, but when updating to this output and shifting, the change in the PWM control signal is mitigated, that is, the duty of the PWM control signal. The ratio (pulse width) is gradually changed from 24% to 54% to set an interpolation period in which the change in the pulse width of the PWM control signal is relaxed and interpolated. Interpolation avoids abrupt changes in the output of the PWM control signal and makes changes slowly.

Specifically, as shown in FIG. 7, the update from the output 24% (start value) of the PWM control signal to the output 54% (total movement 1 value) is set for an interpolation period of 50 ms, and gradually during this period. Will be done. Between the output of the start value of 24% and the cumulative movement of 1 value of 54%, the output of the PWM control signal is updated at 10 equal intervals so as to gradually change every 5 ms (5 ms × 10 = 50 ms).

That is, the interpolation period is set between the output of the start value and the output of the cumulative movement 1, and during this period, the output is interpolated so as to gradually approach the output of the cumulative movement 1 from the output of the start value. Therefore, the output of the PWM control signal is updated within the interpolation period, and this update process ends when the next cumulative movement value is output.

Although the interpolation in the relationship between the output of the start value and the output of the total movement total value has been described, the same interpolation processing is performed in the relationship between the output of the total movement total value and the output of the total movement total value.

Therefore, between the output of the PWM control signal corresponding to the count value of the cumulative movement 1 described in FIGS. 2 and 3 to the output of the PWM control signal corresponding to the count value of the cumulative movement 2, and the count value of the cumulative movement 2. Interference is performed between the output of the corresponding PWM control signal and the output of the PWM control signal corresponding to the count value of the cumulative movement 3, and the interpolation is continuously performed when the next PWM control signal is updated.

As shown again with reference to FIG. 2, in the relationship between the count timing and the interpolation, at the same time as the start of the count (3), the interpolation is performed from the start value to the total movement value at 10 equal intervals every 5 ms. (Output 24% → 53%, 1 interval 2.9%), At the same time as the start of count (4), interpolation is performed from the total movement 1 value to the total movement 2 value at 10 equal intervals every 5 ms (output 53). % → 63%, 1 interval 1%).
Since interpolation is performed when the output of the PWM control signal is updated as described above, it can be expected that the change in the brightness of the light is alleviated and the flicker feeling is suppressed.

The output interval of the measurement sampling signal described above is 1 μs (microseconds) to 2 ms (milliseconds), and each period of count (1), count (2), count (3) ... count (n) is 20 ms ( It is preferable to set the unit count time to 40 ms (milliseconds) to 2 s (seconds) and the interpolation period to 10 μs (microseconds) to 500 ms (milliseconds).

In the PWM conversion method using the PWM conversion circuit described above, the phase control output from the phase control type dimmer 2 as the phase control type dimming unit is input, and the input phase control output is converted into the PWM control output. A PWM converter 3 as a PWM conversion circuit is provided, and a step of generating a DC pulse-like waveform corresponding to the phase control output and the presence or absence of the pulse-like waveform are measured over a fixed unit count time. The step in the step of repeatedly outputting the PWM control signal, including a step of repeatedly counting and measuring with a sampling signal and a step of repeatedly outputting a PWM control signal having a pulse width corresponding to the measurement result based on the measurement result. Between the steps, a step of relaxing and interpolating the change in the pulse width of the PWM control signal is provided.
(Phase control dimmer with different output range)

Next, an example of a phase control type dimmer having a different output range will be described with reference to FIG. FIG. 8 shows the relationship between the count value (count number) of the ON state by the measurement sampling signal and the output of the PWM control signal in a plurality of types of phase control type dimmers having different output ranges. The horizontal axis shows the count value of the output waveform in the ON state, and the vertical axis shows the output (duty ratio) of the PWM control signal.

Three types of phase control dimmers, dimmer A, dimmer B, and dimmer C, were prepared. Generally, the output range (dimming range) differs depending on the type of dimmer, and it is necessary to ensure consistency between the output range of the dimmer and the output on the PWM converter side. Therefore, the minimum and maximum values of the count values in the ON state of the output waveform were investigated. The dimmer A has a minimum value of 256 counts and a maximum value of 7,000 counts, the dimmer B has a minimum value of 1122 counts and a maximum value of 6700 counts, and the dimmer C has a minimum value of 5000 counts and a maximum value of 7600 counts. In FIG. 8, based on this result, the minimum value and the maximum value of the count value of each dimmer are connected by a straight line.

Therefore, by setting the relationship between the count value of the ON state of the output waveform and the output of the PWM control signal according to each dimmer, it is possible to perform dimming by PWM control according to each dimmer.

The specific setting is to rotate the rotation operation knob 21 as the operation unit for dimming the phase control type dimmer 2 shown in FIG. 1 and turn on the selection switch 66 when the maximum phase output is obtained. This is done by turning off the selection switch 66 when the minimum phase output is set. By this operation, the count value when the maximum phase output is set and the count value when the minimum phase output is set can be stored in the storage means of the control processing means 6.

Further, when the maximum phase output is set, the ON / OFF switch 22 of the phase control dimmer 2 is turned ON-OFF twice within 5 seconds, and then turned ON / OFF when the minimum phase output is set within 1 minute. By turning the OFF switch 22 on and off twice within 5 seconds, the count value when the maximum phase output is set and the count value when the minimum phase output is set are stored in the storage means of the control processing means 6. You may do so.

Further, the type may be selected by the selection switch 66 according to the output range of the phase control dimmer 2. In this case, it is preferable to use a rotary type switch for the selection switch 66.
(Another example of how to generate a PWM control signal)
Another example of the method of generating the PWM control signal will be described with reference to FIG. FIG. 9 is a timing chart showing an extracted portion corresponding to a part of FIG.
FIG. 9D shows the output waveform of the photocoupler and shows the relationship with the unit count time for calculating the cumulative movement.

In this example, the unit count times do not overlap. As described above, it is preferable that a part of the unit count time is set in duplicate, but it is not always necessary to overlap. Even if they do not overlap, the presence or absence of pulsed waveforms is counted over a unit count time, so it can be expected that the LED lighting fixture 4 will be dimmed accurately and controlled to be lit by reducing the effects of noise and the like. ..
Further, a predetermined time interval may be provided between the unit count time (cumulative movement 1) and the next unit count time (cumulative movement 2).

As described above, according to the present embodiment, the phase control output from the phase control type dimmer 2 as the phase control type dimmer unit is stably converted into the PWM control output by the PWM converter 3 as the PWM conversion circuit. Can be supplied to the LED lighting fixture 4.

Next, a second embodiment will be described with reference to FIGS. 10 and 11. In the present embodiment, the PWM control signal output from the control processing means 6 is configured as two channels of a plurality of channels. Since the basic configuration is the same as that of the first embodiment, redundant description will be omitted.
(Example 1)

As shown in FIG. 10, the LED luminaire 4 is equipped with a plurality of LEDs 41 having different emission colors and different color temperatures. For example, an LED 41 having a light bulb color and a neutral white emission color is mounted, and the first channel is assigned to the dimming of the LED 41 having a light bulb color and the second channel is assigned to the dimming of the LED 41 having a neutral white light emission color. Can be assigned.
Further, the first channel can be assigned to dimming, and the second channel can be assigned to the dimming ratio of the LED 41 whose emission color is light bulb color and neutral white, that is, the mixed light ratio.

Therefore, it is possible to control dimming by switching channels, and to adjust the ratio of PWM control output according to LEDs of emission colors with different color temperatures to adjust the color, and it is possible to realize various effects. Become.
(Example 2)

As shown in FIG. 11, two LED lighting fixtures 4a and 4b are connected to the PWM converter 3. Therefore, it is possible to switch the channel and individually control the dimming of each of the LED lighting fixtures 4a and 4b.

To switch the channel, the ON / OFF switch 22 of the phase control dimmer 2 is turned on within 5 seconds when the rotation operation knob 21 of the phase control dimmer 2 is rotated to set the minimum phase output. By turning the ON / OFF switch 22 on and off twice within 5 seconds when the maximum phase output is reached within 1 minute after turning on and off twice, the determination unit of the control processing means 6 determines 1 channel. The eye and the second channel can be determined. As a result, the PWM control signal can be switched between the first channel and the second channel, and the PWM control power can be switched between the first channel and the second channel through the drive circuit unit 34 and supplied to the LED lighting fixture 4. It will be possible.

In each of the above embodiments, the LED lighting fixture 4 has a type in which the brightness changes according to the positive logic and a type in which the brightness changes according to the negative logic with respect to the PWM control signal. Therefore, the PWM control signal can be switched between positive logic and negative logic by operating the discrimination switch 65 so as to correspond to each type.

Further, in consideration of the convenience of the dimming operation of the user, the case where the PWM control signal is output proportionally linearly and the case where the PWM control signal is output in a logarithmic manner in consideration of the visual effect are switched. Can be done. Such switching can be performed by the switching setting of the setting changing unit 64 described above.

The present invention is not limited to the configuration of each of the above embodiments, and various modifications can be made without departing from the gist of the invention. Further, the above embodiment is presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other embodiments and can be omitted, replaced, or modified in various ways. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... LED dimming system 2 ... Phase control dimmer 3 ... PWM converter 30 ... Pulse waveform generation unit 31 ... Insulation step-down unit 32 ... Rectifier unit 33 ... Noise removal unit 34・ ・ Drive circuit unit 4 ・ ・ ・ LED lighting fixture 41 ・ ・ LED
5 ... DC power supply unit 6 ... Control processing means 61 ... CPU
62 ... ROM
63 ... RAM
64 ... Setting change unit 65 ... Discrimination switch 66 ... Selection switch 7 ... Load interface unit

Claims (11)

A PWM conversion circuit in which a phase control output from a phase control type dimming unit is input and the input phase control output is converted into a PWM control output.
A pulsed waveform generator that generates a DC pulsed waveform corresponding to the phase control output,
It has a measuring unit that measures the presence or absence of the pulsed waveform by counting how many measurement sampling signals are output by the measurement sampling signal over a certain unit count time, and the measurement result of the measurement unit is used. Based on this, a control processing means that outputs a PWM control signal with a pulse width corresponding to the measurement result, and
A PWM conversion circuit comprising. The PWM conversion circuit according to claim 1, wherein the measurement counted by the measurement sampling signal over a fixed unit count time is repeatedly executed. The PWM conversion circuit according to claim 2, wherein the fixed unit count time is partially duplicated. 2. The PWM conversion circuit according to 3. The fixed unit count time is 40 ms (milliseconds) to 2 s (seconds), and the output interval of the measurement sampling signal is 1 μs (microseconds) to 2 ms (milliseconds). The PWM conversion circuit according to any one of claims 4. The PWM conversion circuit according to any one of claims 1 to 5, wherein the PWM control signal output from the control processing means can be switched between positive logic and negative logic. The PWM conversion circuit according to any one of claims 1 to 6, wherein the PWM control signal output from the control processing means can be switched between a linear output and a logarithmic output. The PWM conversion circuit according to any one of claims 1 to 7, wherein the PWM control signal output from the control processing means is configured as a plurality of channels. A phase control type dimming unit that outputs a phase control output,
The PWM conversion circuit according to any one of claims 1 to 8, which is connected to the phase control type dimming unit.
LED lighting fixtures connected to the PWM conversion circuit
An LED dimming system characterized by being equipped with. By operating the dimming operation unit of the phase control type dimming unit , the value of the count by the measurement sampling signal when the maximum phase output is set and the count value by the measurement sampling signal when the minimum phase output is set. The LED dimming system according to claim 9, wherein the value and the value are stored in the control processing means. A PWM conversion circuit is provided in which a phase control output from a phase control type dimming unit is input and the input phase control output is converted into a PWM control output.
A step of generating a DC pulsed waveform corresponding to the phase control output,
A step of repeatedly counting and measuring how many measurement sampling signals are output by the measurement sampling signal over a certain unit count time for the presence or absence of the pulsed waveform.
Including a step of repeatedly outputting a PWM control signal having a pulse width corresponding to the measurement result based on the measurement result.
A PWM conversion method characterized in that a step of relaxing and interpolating a change in the pulse width of the PWM control signal is provided between the steps in the step of repeatedly outputting the PWM control signal.

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