CN113973411A - Lighting control device and lighting device - Google Patents
Lighting control device and lighting device Download PDFInfo
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- CN113973411A CN113973411A CN202110818535.XA CN202110818535A CN113973411A CN 113973411 A CN113973411 A CN 113973411A CN 202110818535 A CN202110818535 A CN 202110818535A CN 113973411 A CN113973411 A CN 113973411A
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- 238000005286 illumination Methods 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 2
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- 230000003247 decreasing effect Effects 0.000 description 8
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
Provided are a lighting control device and a lighting device. The accuracy of feedback control in lighting control by time-division driving is improved. The lighting control device supplies power to the plurality of light emitting element groups in a time-sharing manner, wherein the controller obtains a current value in a 1 st period by using a digital signal corresponding to a current in the 1 st period, obtains an average value of the currents in a period from an increase to a decrease by using the value of the current in the 1 st period, and increases or decreases the time of an on state of each of the plurality of switching elements according to the average value of the currents, wherein the 1 st period includes at least a period from a time of the increase of the current to a time of reaching a peak value.
Description
Technical Field
The present disclosure relates to a lighting control device and a lighting device.
Background
The following lighting control methods are known: a plurality of light emitting element groups (light emitting element groups) each including 1 or more light emitting elements are driven in a time-sharing manner so that the light emitting periods of the respective groups do not overlap (see, for example, patent document 1). This lighting control method is also referred to as time sharing control.
In the case of using the lighting control method based on the time-sharing driving described above, for example, the voltage generated by the DC-DC converter is supplied to the light emitting elements of each group in a time-sharing manner, and the current flowing at that time is detected and fed back to the DC-DC converter, whereby the voltage supplied to the light emitting elements of each group is controlled to an appropriate level. At this time, the accuracy of current detection may be reduced, and the accuracy of feedback control may be reduced accordingly.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2003-332624
Disclosure of Invention
One of the objects of the present disclosure is to improve the accuracy of feedback control when lighting control by time-division driving is performed.
A lighting control device (a) according to an aspect of the present disclosure supplies power to a plurality of light emitting element groups in a time-sharing manner, and includes: (b) a power supply unit connected to the plurality of light emitting element groups and configured to supply a pulse waveform power; (c) a plurality of switching elements connected between each of the plurality of light emitting element groups and the power supply unit; (d) a current detection circuit connected to a current path from the power supply unit to the plurality of light emitting element groups, and detecting a current flowing through the current path; (e) an analog-to-digital converter connected to the current detection circuit and converting the current detected by the current detection circuit into a digital signal; and (f) a controller connected to the plurality of switching elements, the controller controlling opening and closing of each of the plurality of switching elements based on each of a rise time and a fall time of the current and the digital signal obtained from the analog-to-digital converter, (g) the controller determining a value of the current in a 1 st period using the digital signal corresponding to the current in the 1 st period, determining an average value of the current in a period from the rise time to the fall time using the value of the current in the 1 st period, and increasing or decreasing a time of an open state of each of the plurality of switching elements based on the average value of the current, wherein the 1 st period includes at least a period from the rise time of the current to a peak value.
An illumination device according to an aspect of the present disclosure includes: the lighting control device of the above [1 ]; and a plurality of light emitting element groups connected to the lighting control device and supplied with power in a time-sharing manner.
In the present disclosure, "connected (connected)" may include any of a case where the object a and the object B are directly connected via a wire or the like, and a case where the object a and the object B are indirectly connected via a wire or the like with another object C interposed therebetween.
According to the above configuration, the accuracy of the feedback control at the time of the lighting control by the time-division driving can be improved.
Drawings
Fig. 1 is a diagram showing a configuration of a lighting control device and a light emitting element group controlled by the lighting control device according to an embodiment.
Fig. 2 (a) to 2 (F) are timing charts for explaining basic operations of the lighting control device.
Fig. 3 (a) and 3 (B) are waveform diagrams showing a relationship between an output voltage of the DC-DC converter and a current flowing through the light emitting element group, respectively.
Fig. 4 (a) is a waveform diagram for explaining a current detection method, and fig. 4 (B) is a waveform diagram for explaining a feedback control method.
Description of the reference symbols
1: a lighting control device; 2: a power source; 3 a; 3 b: a light emitting element group; 4: a reference power supply; 10: a DC-DC converter; 11: a current detection circuit; 12: a controller; 13: a light-on time detection circuit; 14 a; 14 b: a switching element; 15: a resistance element; 21: a peak current detection unit; 22: an I/V conversion section; 23: an analog-to-digital converter; 24: a comparator.
Detailed Description
Fig. 1 is a diagram showing a configuration of a lighting control device and a light emitting element group controlled by the lighting control device according to an embodiment. The lighting control device 1 shown in the figure receives power supply from the power supply 2, generates a drive voltage, and supplies the drive voltage (power) to the light emitting element groups 3a and 3b in a time-sharing manner. The lighting control device 1 of the present embodiment controls the light emitting element groups 3a and 3b constituting various lamps included in a vehicle. The power source 2 is, for example, a battery of a vehicle. The lighting control device 1, the light emitting element group 3a, and the light emitting element group 3b constitute a vehicle lamp as an example of a lighting device. The light emitting element group 3a is used to illuminate a low beam (passing light), for example, and the light emitting element group 3b is used to illuminate a high beam (running light), for example.
The lighting control device 1 includes a DC-DC converter 10, a current detection circuit 11, a controller 12, a lighting time detection circuit 13, and 2 switching elements 14a and 14 b. In addition, the lighting time detection circuit corresponds to a "waveform detection circuit".
The DC-DC converter 10 is connected to the power supply 2, and generates an output voltage (driving voltage) having a voltage value suitable for driving the light emitting element group 3a or the light emitting element group 3b by stepping up or stepping down a DC voltage obtained from the power supply 2.
The current detection circuit 11 is connected to the DC-DC converter 10, generates a signal necessary for the operation of the DC-DC converter 10, and includes a resistance element 20, a peak current detection unit 21, and an I/V conversion unit (conversion unit) 22. The current detection circuit 11 is configured to include an integrated circuit, for example.
The resistance element 20 is connected to a wiring (i.e., on a current path) connecting between the DC-DC converter 10 and each of the light emitting element groups 3a, 3 b.
The peak current detection unit 21 is connected to both ends of the resistance element 20, and detects the maximum current (peak current) flowing through the resistance element 20. More specifically, the current detection unit 21 is connected to the DC-DC converter 10, generates a voltage signal that changes in accordance with the magnitude of the peak current flowing through the resistance element 20, and supplies the voltage signal to the DC-DC converter 10. The DC-DC converter 10 uses this voltage signal as a feedback signal to adjust the output voltage so that the peak current remains substantially constant.
The I/V conversion unit 22 obtains a current flowing through the resistance element 20 via the peak current detection unit 21, and converts the current (I) into a signal of a voltage (V).
The controller 12 controls the opening and closing operations of the switching elements 14a and 14 b. The controller 12 is realized by executing a predetermined operation program in a computer system using the computer system having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The controller 12 of the present embodiment incorporates an analog-digital converter (ADC) 23.
An analog-to-digital converter (ADC)23 is connected to the I/V conversion unit 22, and converts the voltage input from the I/V conversion unit 22 into a digital signal. In the present embodiment, the analog-digital converter 23 is incorporated in the controller 12, but may be incorporated in a separate form without being incorporated.
The lighting time detection circuit 13 is a circuit for detecting the lighting time of the light emitting element group 3a or the light emitting element group 3b, and is connected to the I/V conversion section 22 and to the controller 12. The lighting time detection circuit 13 has a comparator 24.
A comparator (comparator)24 has one input terminal connected to the I/V conversion section 22, the other input terminal connected to the reference power source 4 for supplying the reference voltage Vrf, and an output terminal connected to the controller 12. The comparator 24 sets the output voltage from the output terminal to any one of 2 voltages having relatively different magnitudes, based on the magnitude relationship between the voltage output from the I/V conversion unit 22 and the reference voltage Vrf. The reference voltage Vrf is set as appropriate so that the voltage from the output terminal becomes the 1 st value (for example, high level) only during the period when current flows through the resistance element 20, and becomes the 2 nd value (for example, low level) during the period when current does not substantially flow. That is, the lighting time detection circuit 13 of the present embodiment including the comparator 24 functions as a waveform detection circuit that detects each timing of rising and falling of the current. Therefore, the controller 12 can determine the lighting time of the light emitting element group 3a or the light emitting element group 3b based on the magnitude of the voltage at the output terminal of the comparator 24.
The switching element 14a has a 1 st input/output terminal connected to the DC-DC converter 10 via the resistance element 20, a 2 nd input/output terminal connected to the light emitting element group 3a, and a control terminal connected to the controller 12. The switching element 14a is controlled to be turned on/off according to a control signal supplied from the controller 12 to the control terminal. The term "on" as used herein means a state (on state) in which a current easily flows between the 1 st input terminal and the 2 nd input terminal, and "off" means a state (off state) in which a current hardly flows between the 1 st input terminal and the 2 nd input terminal.
The switching element 14b has a 1 st input/output terminal connected to the DC-DC converter 10 via the resistance element 20, a 2 nd input/output terminal connected to the light emitting element group 3b, and a control terminal connected to the controller 12. The switching element 14b is controlled to be turned on/off according to a control signal supplied from the controller 12 to the control terminal. The meanings of "on" and "off" are the same as described above.
In the present embodiment, although a field effect transistor is shown as an example of the switching elements 14a and 14b in the figure, the present invention is not limited to this. Each of the switching elements 14a and 14b may be a bipolar transistor, for example. In the present embodiment, the controller 12 controls the on/off of the switching elements 14a and 14b in a time-sharing manner, thereby controlling the light emitting element group 3a and the light emitting element group 3b not to be turned on at the same time but to be turned on in a time-sharing manner.
The light emitting element group 3a includes 5 light emitting elements (LEDs) connected in series, and one end is connected to the DC-DC converter 10 and the other end is connected to a reference potential terminal (so-called GND). The light emitting element group 3b includes 8 light emitting elements (LEDs) connected in series, and one end is connected to the DC-DC converter 10 and the other end is connected to a reference potential terminal (so-called GND). In the present embodiment, the light emitting element group 3a and the light emitting element group 3b are connected in parallel to the DC-DC converter 10. Since the numbers of light emitting elements in the light emitting element group 3a and the light emitting element group 3b are different from each other, the sizes of the loads (resistance values) of the respective elements are different from each other.
Fig. 2 (a) to 2 (F) are timing charts for explaining basic operations of the lighting control device. Specifically, (a) of fig. 2 is a waveform diagram showing the on/off state of the switching element 14a, (B) of fig. 2 is a waveform diagram showing the on/off state of the switching element 14B, (C) of fig. 2 is a waveform diagram showing the on/off state based on the PWM control of the DC-DC converter 10, (D) of fig. 2 is a waveform of a current flowing in the light emitting element group 3a, (E) of fig. 2 is a waveform of a current flowing in the light emitting element group 3B, and (F) of fig. 2 is a waveform of an output voltage of the DC-DC converter 10. In fig. 2 (a) and 2 (B), the case where the waveform is at a relatively high level indicates "on" of the switching elements 14a and 14B, and the case where the waveform is at a relatively low level indicates "off" of the switching elements 14a and 14B. In fig. 2 (C), the case where the waveform is at a relatively high level indicates a state where a voltage is output from the DC-DC converter 10, and the case where the waveform is at a relatively low level indicates a state where a voltage is not output from the DC-DC converter 10.
As shown in fig. 2C, the DC-DC converter 10 is subjected to PWM (Pulse Width Modulation) control, and repeatedly turned on and off at a predetermined duty ratio to generate a Pulse-shaped voltage. When the switching element 14a is turned on (fig. 2 (a)) when the duty ratio of the DC-DC converter 10 is on, the output voltage of the DC-DC converter 10 rises after a delay time td1 (for example, 10 μ s) elapses to become a fixed value corresponding to the load of the light emitting element group 3a ((F) of fig. 2). At this time, the output voltage of the DC-DC converter 10 gradually increases until it takes a certain amount of time to reach a fixed value, and therefore, the current flowing through the light emitting element group 3a also gradually increases in accordance with the increase, and thereafter, the current is maintained at the fixed value and changes ((D) of fig. 2). When the switching element 14a is turned off (fig. 2 a), the current flowing through the light emitting element group 3a becomes substantially 0 (fig. 2D). The delay time td1 is provided to turn on the light emitting element group 3a before the output of the DC-DC converter 10 is started, thereby preventing abnormal voltage increase of the DC-DC converter 10.
When a certain time elapses after the switching element 14a is turned off and the switching element 14B is turned on (fig. 2 (B)), the output voltage of the DC-DC converter 10 rises by a delay time td2 (for example, 10 μ s) between when the PWM signal of the DC-DC converter 10 is turned on, and then the output voltage becomes a fixed value corresponding to the load of the light emitting element group 3B ((F) of fig. 2). In this way, in the present embodiment, the output voltage of the DC-DC converter 10 is increased after the switching element 14b is turned on. Similarly to the above-described delay time td1, the delay time td2 is provided to prevent abnormal boosting of the DC-DC converter 10.
In the present embodiment, the load of the light emitting element group 3b is larger than that of the light emitting element group 3a, and therefore the output voltage is also large. Therefore, the time required for the output voltage to reach a fixed value also becomes long. The current flowing through the light emitting element group 3b gradually increases in accordance with the gradual increase in the output voltage of the DC-DC converter 10, and then changes while being kept at a constant value ((E) of fig. 2). When the switching element 14B is turned off (fig. 2B), the current flowing through the light emitting element group 3B becomes substantially 0 (fig. 2E).
If a period from when the switching element 14a is turned on and then turned off, then the switching element 14b is turned on and then turned off, and then the switching element 14a is turned on after a certain time has elapsed is defined as 1 cycle, the length T of the 1 cycle can be, for example, about 5000 μ s (corresponding to 200 Hz). In the present embodiment, the on period of the switching element 14a is set to be relatively longer than the on period of the switching element 14b in 1 cycle.
The target values of the peak current value and the duty ratio are set so that the average value of the current flowing through the light emitting element group 3A in 1 cycle T is, for example, 1.3A. Similarly, the target values of the peak current value and the duty ratio are set so that the average value of the peak current value and the duty ratio in 1 period T becomes, for example, 0.05A with respect to the current flowing through the light emitting element group 3 b. These duty ratios can be set by the on period and the off period of the switching elements 14a and 14b described above.
Here, the DC-DC converter 10 of the present embodiment controls the output voltage so that the peak current is substantially constant. Therefore, in order to increase or decrease the average value of the currents flowing through the light emitting element groups 3a and 3b, the time for which the currents flow may be increased or decreased. In the present embodiment, the controller 12 variably sets the lengths of the on periods and the off periods of the switching elements 14a and 14b, thereby increasing and decreasing the time during which the current flows through each of the light emitting element groups 3a and 3 b.
Fig. 3 (a) and 3 (B) are waveform diagrams showing a relationship between an output voltage of the DC-DC converter and a current flowing through the light emitting element group, respectively. In each figure, the upper section shows an output voltage, and the lower section shows a current. The DC-DC converter 10 of the present embodiment performs control for automatically switching 3 control modes, i.e., the step-up mode, the step-down mode, and the step-down mode, according to the magnitude of the output voltage. Therefore, when the relationship between the input voltage from the power supply 2 and the output voltage of the DC-DC converter 10 reaches the switching voltage of the control mode, a delay occurs in the rise time of the output voltage.
When the switching of the control mode does not occur, the output voltage rises as a linear function (straight line) as shown in the upper stage of fig. 3a, and then changes while being held at a fixed value, and accordingly, the current also shows the same change as shown in the lower stage of fig. 3 a. In this case, by detecting the time (lighting time) t during which the current flows, the output voltage of the DC-DC converter 10 can be controlled with high accuracy.
On the other hand, when switching of the control mode occurs, as shown in the upper stage of (B) of fig. 3, the output voltage does not increase as a linear function, but increases in a stepwise manner with a period in between during which the output voltage does not increase due to switching of the control mode. Therefore, as shown in the lower stage of fig. 3 (B), the current does not reach the peak current (Ipk) immediately, but a period in which the current is relatively low is interposed therebetween. In this case, it is difficult to accurately control the output voltage of the DC-DC converter 10 by detecting only the time (lighting time) t during which the current flows. This is because the average value of the current flowing in the light emitting element group 3a (or 3b) is reduced as compared with the case where there is no switching of the control mode. Therefore, in the present embodiment, the controller 12 controls the time for which the switching elements 14a and 14b are turned on in accordance with the rise and fall of the current detected by the lighting time detection circuit 13, thereby controlling the current to approach an appropriate value. This will be described in detail below.
Fig. 4 (a) is a waveform diagram for explaining a current detection method. In addition, since the current flowing through the resistance element 20 is actually converted into a voltage by the I/V conversion unit 22 and the magnitude of the current is detected by the voltage, the voltage waveform is shown in fig. 4 (a). The controller 12 detects a rise time (start time) of the current based on the voltage level (high/low) of the voltage signal output from the lighting time detection circuit 13. The controller 12 converts the voltage signal output from the I/V conversion unit 22 at a constant sampling period Δ t into a digital signal by the analog-digital converter 23 and reads the digital signal. In the figure, the sampling points are illustrated with black dots for ease of understanding.
The controller 12 acquires the value of the current from the digital signal obtained by the analog-digital converter 23 in the 1 st period (in the present embodiment, the period including at least the period from the rise time of the current to the time when the peak current (Ipk) is reached (and the period including the period until a predetermined time elapses after the peak current Ipk is reached). In the 2 nd period including at least a period from when the current reaches the peak current (Ipk) to when the current falls (end period), the controller 12 detects the time during which the current flows from the output voltage of the lighting time detection circuit 13. Specifically, the controller 12 detects the fall period of the current based on the voltage level (high/low) of the voltage signal output from the lighting time detection circuit 13. The time from the start period of the 2 nd period to the fall period of the current becomes the time of the 2 nd period. Further, the controller 12 sets the boundary between the 1 st period and the 2 nd period as appropriate.
In the 1 st period corresponding to the rise of the current, the waveform change can be reliably detected using the digital signal converted by the analog-digital converter 23. On the other hand, when a waveform change in the entire period in which the 1 st period and the 2 nd period are combined is detected from the digital signal of the analog-digital converter 23, the sampling frequency cannot follow a sharp drop in the current, and a period of the drop in the current (end period of the 2 nd period) cannot be reliably detected. Therefore, the end period of the 2 nd period can be detected more reliably by detecting the end period using the lighting time detection circuit 13 formed of an analog circuit, processing the voltage at the output terminal of the comparator 24 as a logic signal (digital signal), and taking in the logic signal from the input port for the digital signal of the controller 12.
The controller 12 integrates the magnitude of the current at each sampling point in the 1 st period in accordance with the sampling period, integrates the magnitude of the peak current in the 2 nd period and the time during which the peak current flows, adds the magnitudes and averages them, and thereby obtains the magnitude of the average current (current average value) of the entire 1 st and 2 nd periods. Then, the controller 12 compares the average current value with a preset reference value, and increases or decreases the time (on time) for which the current flows through the light emitting element group 3a (or 3B) based on the difference between the average current value and the reference value, as shown in fig. 4B. Specifically, as shown in the figure, the length of the on time is increased or decreased by moving the end period of the on time forward or backward. For example, when the average value of the current is smaller than the reference value, the on time is extended according to the difference. In addition, when the average value of the current is larger than the reference value, the on time is shortened according to the difference. Specifically, the controller 12 increases or decreases the on time by controlling the length of the period during which the switching elements 14a and 14b are turned on. This enables reliable feedback control corresponding to the current average value.
As described above, according to the present embodiment, the accuracy of feedback control in lighting control by time-division driving of a plurality of light emitting element groups can be improved.
The present disclosure is not limited to the above embodiments, and various modifications can be made within the scope of the present disclosure. For example, in the above-described embodiment, the case where 2 light emitting element groups are time-divisionally driven is exemplified, but the number of light emitting element groups may be 3 or more. The number of light-emitting elements included in each light-emitting element group is also an example, and is not limited to the number in the above embodiments. In the present disclosure, the number of light emitting elements included in each light emitting element group may be at least 1 or more. The application of the light emitting element group is not limited to the vehicle lamp, and can be applied to various lighting devices.
In the above-described embodiment, the feedback control is realized by increasing or decreasing the supply time (on time) of the current to each light-emitting element group, but the feedback control may be realized by increasing or decreasing the peak current. In this case, the peak current may be increased or decreased by supplying a control signal from the controller 12 to the DC-DC converter 10 and increasing or decreasing the output voltage according to the average current value. Further, such peak current-based control and on-time-based control may also be used in combination. The peak current value and/or the average current value of the current supplied to each light emitting element group may be the same or different.
In the above-described embodiment, the fall time of the current is detected by using the lighting time detection circuit as an analog circuit, but the fall time may be detected from a digital signal obtained from an analog-digital converter when the sampling period of the analog-digital converter is very short.
Further, the DC-DC converter of the above embodiment has 3 control modes, but may have at least 2 control modes. In the above-described embodiment, the DC-DC converter is used as an example of the power supply unit that supplies the pulse-shaped power, but the power supply unit is not limited to this.
Claims (8)
1. A lighting control device that supplies power to a plurality of light-emitting element groups in a time-sharing manner, the lighting control device comprising:
a power supply unit connected to the plurality of light emitting element groups and configured to supply a pulse waveform power;
a plurality of switching elements connected between each of the plurality of light emitting element groups and the power supply unit;
a current detection circuit connected to a current path from the power supply unit to the plurality of light emitting element groups, and detecting a current flowing through the current path;
an analog-to-digital converter connected to the current detection circuit and converting the current detected by the current detection circuit into a digital signal; and
a controller connected to the plurality of switching elements, for controlling the opening and closing of each of the plurality of switching elements based on each of the rising and falling times of the current and the digital signal obtained from the analog-to-digital converter,
the controller obtains a value of the current in a 1 st period using the digital signal corresponding to the current in the 1 st period, obtains an average value of the current in a period from the rise to the fall using the value of the current in the 1 st period, and increases or decreases the time of the on state of each of the plurality of switching elements based on the average value of the current, wherein the 1 st period includes at least a period from a time when the current rises to a time when the current reaches a peak.
2. The lighting control device according to claim 1,
the lighting control device further includes a waveform detection circuit connected to the current detection circuit for detecting a rise and a fall of the current detected by the current detection circuit,
the controller obtains a length of a 2 nd period from an output of the waveform detection circuit, and obtains an average value of the current using the length of the 2 nd period, wherein the 2 nd period includes at least a period from a lapse of the 1 st period to a period of the fall of the current.
3. The lighting control device according to claim 2,
the controller obtains a 1 st average value of the current in the 1 st period from the digital signal and a sampling period thereof, obtains a 2 nd average value of the current in the 2 nd period from a length of time from an end period of the 1 st period to a period of time during which the current falls, and obtains an average value of the current from the 1 st average value and the 2 nd average value.
4. The lighting control device according to any one of claims 1 to 3,
the power supply unit is a DC-DC converter that operates by autonomously switching among at least 2 operation modes of a step-up mode, a step-down mode, and a step-up/step-down mode.
5. The lighting control device according to any one of claims 1 to 4,
the analog-to-digital converter is built in the controller.
6. The lighting control device according to any one of claims 1 to 5,
the current detection circuit includes a resistance element connected to the current path and a conversion unit that converts a current flowing through the resistance element into a voltage,
the analog-digital converter converts the voltage obtained from the conversion section into a digital signal.
7. The lighting control device according to any one of claims 1 to 6,
the load of each of the plurality of light emitting element groups is different in magnitude, and the peak values of currents flowing through the plurality of light emitting element groups at the time of lighting are different from each other.
8. An illumination device, wherein the illumination device comprises:
the lighting control device according to any one of claims 1 to 7; and
and a plurality of light emitting element groups connected to the lighting control device and supplied with power in a time-sharing manner.
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| JP2020-125043 | 2020-07-22 | ||
| JP2020125043A JP2022021467A (en) | 2020-07-22 | 2020-07-22 | Lighting control device, lighting device |
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| CN113973411A true CN113973411A (en) | 2022-01-25 |
| CN113973411B CN113973411B (en) | 2024-03-08 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11832360B1 (en) | 2022-10-19 | 2023-11-28 | Leotek Corporation | Lamp device and light-emitting control method thereof |
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| US11832360B1 (en) | 2022-10-19 | 2023-11-28 | Leotek Corporation | Lamp device and light-emitting control method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113973411B (en) | 2024-03-08 |
| JP2022021467A (en) | 2022-02-03 |
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