JP5669604B2 - Light source circuit, lighting device and lighting system - Google Patents

Description

  The present invention relates to a light source circuit having a light source such as a light emitting diode (LED).

There is a technique for adjusting the power supplied to the lighting device by controlling the phase of the power supplied to the lighting device in order to dimm the light emitted by the lighting device.
An illuminating device using a light source such as an LED does not directly supply input power to the light source, but converts it to DC power and supplies it to the light source.

JP 2004-296205 A JP 2010-44399 A

A light source such as an LED does not emit light unless the voltage across it exceeds a certain threshold. When the conduction angle is small, a power supply circuit that generates power to be supplied to a light source circuit in which a large number of light sources such as LEDs are connected in series has a voltage value of direct-current power generated from the power-on to a voltage that can light the light source. It may take some time to reach. For this reason, the user may recognize a failure or a reaction delay.
The present invention has been made, for example, in order to solve the above-described problems, and has an object to shorten the time required from turning on the power source to turning on the light source when the conduction angle is small with a simple configuration.

  A light source circuit according to the present invention has a plurality of light emitting diodes electrically connected in series and a light source parallel impedance electrically connected in parallel to any of the plurality of light emitting diodes, and the light source parallel impedance is a capacitor Or it is a series circuit of a resistor or a capacitor and a resistor.

  According to the light source circuit of the present invention, since the light-emitting diode whose light source parallel impedance is not electrically connected in parallel is turned on by the current flowing through the light source parallel impedance, the time required from turning on the power to turning on the light source is shortened.

FIG. 3 is a perspective view illustrating an appearance of a lighting device 820 in Embodiment 1. FIG. 3 is a front view showing the shape of the light source module 110 in the first embodiment. FIG. 2 is a system configuration diagram showing a configuration of an illumination system 800 in the first embodiment. FIG. 3 is a circuit diagram showing a circuit configuration of a phase control dimmer 810, a power supply circuit 821, and a light source circuit 100 in the first embodiment. FIG. 3 is a timing chart illustrating an example of voltages and currents of respective units of the lighting system 800 according to Embodiment 1. FIG. 6 shows an example of voltage-current characteristics of a light source 111 and a light source circuit 100 in Embodiment 1. FIG. 3 is a timing chart illustrating an example of voltage / current of the light source circuit 100 according to the first embodiment. FIG. 6 is a circuit diagram illustrating a circuit configuration of a lighting device 820 in Embodiment 2. FIG. 10 is a front view showing the shape of the light source module 110 according to the third embodiment. FIG. 9 is a circuit diagram illustrating a circuit configuration of a lighting device 820 in Embodiment 3. FIG. 9 is a circuit diagram illustrating a circuit configuration of a lighting device 820 in Embodiment 4. FIG. 10 is a timing chart illustrating an example of voltage and current of the light source circuit 100 according to Embodiment 4. FIG. 9 is a circuit diagram illustrating a circuit configuration of a lighting device 820 according to Embodiment 5. FIG. 16 is a timing chart showing an example of voltage / current of the light source circuit 100 according to the fifth embodiment.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

FIG. 1 is a perspective view showing the appearance of the illumination device 820 in this embodiment.
The lighting device 820 includes a plurality of light sources 111. The light source 111 is an element that emits light by electric energy, such as an LED. The plurality of light sources 111 may be the same light source or different light sources.

FIG. 2 is a front view showing the shape of the light source module 110 in this embodiment.
The light source module 110 is a substrate 115 on which a light source 111 and a light source parallel resistor 112 are mounted. The substrate 115 is, for example, a disk-shaped printed wiring board, and has printed wiring that connects between the light source 111 and the light source parallel resistor 112.

FIG. 3 is a system configuration diagram showing the configuration of the illumination system 800 in this embodiment.
The lighting device 820 includes a power supply circuit 821 and a light source circuit 100. The light source circuit 100 is a circuit formed by connecting a light source 111 and a light source parallel resistor 112 mounted on a substrate 115 of the light source module 110 by printed wiring. The power supply circuit 821 generates DC power for lighting the light source 111 and supplies it to the light source circuit 100.

The illumination system 800 includes a phase control dimmer 810 and an illumination device 820.
The illumination system 800 turns on the light source 111 of the illumination device 820 in response to power supplied from an AC power source AC such as a commercial power source. The illumination system 800 has a dimming function and can adjust the brightness at which the light source 111 is turned on.
The phase control dimmer 810 inputs the dimming rate, and phase-controls the voltage waveform of the power supplied from the AC power supply AC according to the input dimming rate. The illumination device 820 inputs the power phase-controlled by the phase control dimmer 810 and turns on the light source 111.

FIG. 4 is a circuit diagram showing the circuit configuration of the phase control dimmer 810, the power supply circuit 821, and the light source circuit 100 in this embodiment.
The phase control dimmer 810 includes, for example, a dimming input unit 811, a bidirectional thyristor 812, and a drive circuit 813. The dimming input unit 811 inputs the dimming rate. The dimming input unit 811 inputs a signal representing the dimming rate, such as a dimming signal that has been subjected to pulse width modulation or an infrared signal from a remote controller. Or the dimming input part 811 inputs the state of the operation knob and operation switch which a user operates and designates a dimming rate. The drive circuit 813 generates a drive pulse that turns on the bidirectional thyristor 812 based on the dimming rate input by the dimming input unit 811. The bidirectional thyristor 812 is a kind of switching element, and is turned on when a driving pulse generated by the driving circuit 813 is input, and is automatically turned off when the flowing current becomes zero.
In addition, the phase control dimmer 810 may have a configuration including a power switch that cuts off the electric power from the AC power supply separately from the bidirectional thyristor 812.

  The power supply circuit 821 includes, for example, a rectifier circuit and a DC / DC conversion circuit. The rectifier circuit is, for example, a diode bridge DB. The DC / DC converter circuit is, for example, a flyback converter circuit including a control circuit 822, a switching element Q23, a transformer T24, a diode D27, and a smoothing capacitor C28. The diode bridge DB inputs the power phase-controlled by the phase control dimmer 810, performs full-wave rectification, and makes the voltage waveform pulsating. The control circuit 822 generates a control signal for turning on / off the switching element Q23 at a high frequency. The transformer T24 has a primary winding L25 and a secondary winding L26 that are tightly coupled with each other. The primary winding L25 is electrically connected in series with the switching element Q23. When the switching element Q23 is turned on, a pulsating voltage obtained by full-wave rectification of the diode bridge DB is applied to the primary winding L25, and a current flows. When the switching element Q23 is turned off, the current flowing through the primary winding L25 becomes 0 and the current flows through the secondary winding L26. Secondary winding L26, diode D27, and smoothing capacitor C28 form a closed circuit. The current flowing through the secondary winding L26 is rectified by the diode D27 and charges the smoothing capacitor C28. The voltage across the smoothing capacitor C28 is applied to the light source circuit 100.

  The light source circuit 100 includes a plurality of (for example, seven) light sources 111 and a light source parallel resistor 112 (light source parallel impedance). When there are a plurality of the same elements, they may be distinguished by adding an alphabet after the code. The plurality of light sources 111 are electrically connected in series. The light source parallel resistor 112 is electrically connected in parallel with at least one of the plurality of light sources 111. In this example, four light source parallel resistors 112a to 112d are electrically connected in parallel with the light sources 111a to 111d, respectively.

FIG. 5 is a timing chart showing an example of voltages and currents of respective parts of the illumination system 800 in this embodiment.
The horizontal axis indicates time. The vertical axis represents voltage or current. A voltage 711 indicated by a solid line is a voltage value of AC power input by the lighting system 800. A voltage 712 indicated by a solid line is a voltage value of power phase-controlled by the phase control dimmer 810. A current 721 indicated by a solid line is a current flowing through the secondary winding L26 of the transformer T24. A voltage 713 indicated by a solid line is a voltage across the smoothing capacitor C28.

The drive circuit 813 of the phase control dimmer 810 detects that the input AC power voltage has crossed zero, and when the delay time according to the dimming rate input by the dimming input unit 811 has elapsed, the bidirectional thyristor A drive pulse for turning on 812 is generated. The delay time is shorter than a half cycle of the AC power, shorter as the dimming rate is higher (brighter), and longer as the dimming rate is lower (darker). The bi-directional thyristor 812 remains on until it is automatically turned off at the next zero cross.
For example, at time 731 indicated by a broken line, the drive circuit 813 detects a zero cross. At time 732 indicated by a broken line, the delay time elapses, the drive circuit 813 generates a drive pulse, and the bidirectional thyristor 812 is turned on. At time 733 indicated by a broken line, the bidirectional thyristor 812 is automatically turned off. By repeating this, the phase control dimmer 810 supplies the phase-controlled power to the lighting device 820.

  In the power supply circuit 821 of the lighting device 820, the control circuit 822 turns on and off the switching element Q23 at a high frequency, so that a sawtooth current 721 flows through the secondary winding L26. The control circuit 822 improves the power factor of the lighting device 820 by turning on and off the switching element Q23 so that the average value of the current 721 is similar to the absolute value of the voltage 712.

The smoothing capacitor C28 is charged by the current 721 flowing through the secondary winding L26.
Immediately after the power is turned on, the voltage across the smoothing capacitor C28 is zero, and no current flows through the light source circuit 100, so the voltage 713 across the smoothing capacitor C28 increases. As the voltage across the smoothing capacitor C28 increases, current begins to flow through the light source circuit 100. When the voltage 713 across the smoothing capacitor C28 reaches a voltage at which the current 721 flowing through the secondary winding L26 and the current flowing through the light source circuit 100 are balanced, the smoothed capacitor C28 reaches an equilibrium state.

  If the conduction angle (the length of the period in which the bidirectional thyristor 812 is on is expressed by the phase angle of the AC power) is large, the total amount of the current 721 flowing through the secondary winding L26 increases, so that the current flowing through the light source circuit 100 Becomes larger and the light source 111 is lit brightly. If the conduction angle is small, the total amount of current 721 flowing through the secondary winding L26 is reduced, so that the current flowing through the light source circuit 100 is reduced and the light source 111 is lit dark.

Note that the frequency of the AC power supply AC is, for example, 50 Hz to 60 Hz. Accordingly, the length of the half cycle is, for example, 8.3 milliseconds to 10 milliseconds. During this time, if the voltage 713 across the smoothing capacitor C28 changes greatly, the current flowing through the light source circuit 100 changes significantly, causing the light source 111 to flicker. In order to prevent this, the smoothing capacitor C28 has a considerably large capacitance of about 2200 μF to 3300 μF, for example.
Since the capacitance of the smoothing capacitor C28 is large, the voltage 713 across the smoothing capacitor C28 after power-on rises slowly. Furthermore, the smaller the conduction angle, the smaller the rate of increase of the voltage 713 across the smoothing capacitor C28.

FIG. 6 is a diagram showing an example of voltage-current characteristics of the light source 111 and the light source circuit 100 in this embodiment.
The horizontal axis represents voltage. The vertical axis represents current. A characteristic 741 and a characteristic 742 indicated by solid lines indicate the voltage / current characteristics of the light source 111 alone. The characteristic 742 shows the case where the current is very small, and the vertical axis is enlarged. A characteristic 743 and a characteristic 744 indicated by a solid line indicate a voltage-current characteristic of the entire light source circuit 100. A characteristic 745 and a characteristic 746 indicated by a broken line indicate the relationship between the voltage applied to the entire light source circuit 100 and the current flowing through the light source 111 to which the light source parallel resistor 112 is connected in parallel. The characteristic 744 and the characteristic 746 are enlarged in the vertical axis, like the characteristic 742. Note that the characteristic 745 almost overlaps with the characteristic 743.
A current 722 indicated by a broken line emits the light source 111 at a predetermined luminance (hereinafter referred to as “minimum visual luminance”) that is predetermined as a minimum luminance that can be visually recognized by the user of the lighting device 820 when the light source 111 emits light. Therefore, the current to be passed through the light source 111 (hereinafter referred to as “minimum visual recognition current”) is shown. A current 723 indicated by a broken line is obtained when the conduction angle of the AC power input by the lighting device 820 is a predetermined conduction angle (hereinafter referred to as “minimum conduction angle”) that is predetermined as the minimum value of the conduction angle. A current flowing through the light source circuit 100 (hereinafter referred to as “minimum current”) is shown. A current 724 indicated by a broken line is obtained when the conduction angle of the AC power input by the lighting device 820 is a predetermined conduction angle (hereinafter referred to as “maximum conduction angle”) that is predetermined as the maximum value of the conduction angle. A current flowing through the light source circuit 100 (hereinafter referred to as “maximum current”) is shown.

A voltage 714 indicated by a broken line is a voltage across the light source 111 when the current flowing through the light source 111 is the minimum visible current 722 (hereinafter referred to as “minimum visible voltage”). For example, when the minimum visual current 722 is 100 μA, the voltage 714 is, for example, 2.4V.
A voltage 715 indicated by a broken line indicates a voltage across the light source 111 when the current flowing through the light source 111 is the minimum current 723 (hereinafter referred to as “minimum voltage”). For example, when the minimum current 723 is 20 mA, the voltage 715 is, for example, 2.64V.
A voltage 716 indicated by a broken line indicates a voltage across the light source 111 when the current flowing through the light source 111 is the maximum current 724 (hereinafter referred to as “maximum voltage”). For example, when the maximum current 724 is 600 mA, the voltage 716 is, for example, 3.26V.
Note that the voltage-current characteristics differ depending on the light source 111, and thus the above-described numerical value is an example.

ただし、Ｖ_Ｌは、光源回路１００の両端電圧である。Ｉ_ｖは、最小視認電流７２２である。Ｒは、光源並列抵抗１１２の抵抗値である。Ｖ_Ｆｖは、光源並列抵抗１１２が並列接続していない光源１１１の最小視認電圧７１４である。なお、光源並列抵抗１１２の抵抗値Ｒは、次の式を満たす。

ただし、Ｖ’_Ｆｖは、光源並列抵抗１１２が並列接続した光源１１１の最小視認電圧７１４である。
例えば、上述した数値例によれば、最小視認電流７２２が１００μＡ、最小視認電圧７１４が２．４Ｖだから、光源並列抵抗１１２の抵抗値Ｒは、２４ｋΩ（＝２．４Ｖ／１００μＡ）以下である。 A voltage 717 indicated by a broken line indicates a voltage across the light source circuit 100 when the current flowing through the light source circuit 100 is the minimum visible current 722. The both-end voltage 717 is expressed by the following equation.

However, V _L is the voltage across the light source circuit 100. _Iv is the minimum visual current 722. R is the resistance value of the light source parallel resistor 112. V _Fv is the minimum visual voltage 714 of the light source 111 to which the light source parallel resistor 112 is not connected in parallel. The resistance value R of the light source parallel resistor 112 satisfies the following expression.

However, V ′ _Fv is the minimum visual recognition voltage 714 of the light source 111 to which the light source parallel resistor 112 is connected in parallel.
For example, according to the numerical example described above, since the minimum visible current 722 is 100 μA and the minimum visible voltage 714 is 2.4 V, the resistance value R of the light source parallel resistor 112 is 24 kΩ (= 2.4 V / 100 μA) or less.

ただし、ｎ_１は、光源並列抵抗１１２が並列接続した光源１１１の数である。ｎ_２は、光源並列抵抗１１２が並列接続していない光源１１１の数である。 If the minimum visual recognition voltages 714 of the light sources 111 are all equal and the resistance values of the light source parallel resistors 112 are all equal,

However, _{n 1} is the number of light sources 111 in which the light source parallel resistor 112 is connected in parallel. n ₂ is the number of light sources 111 to which the light source parallel resistors 112 are not connected in parallel.

  A voltage 718 indicated by a broken line indicates a voltage across the light source circuit 100 when the current flowing through the light source 111 to which the light source parallel resistor 112 is connected in parallel is the minimum visual current 722. A voltage 719 indicated by a broken line indicates a voltage across the light source circuit 100 when the current flowing through the light source circuit 100 is the minimum current 723. A voltage 720 indicated by a broken line indicates a voltage across the light source circuit 100 when the current flowing through the light source circuit 100 is the maximum current 720.

  For example, the number of the light sources 111 is 7, of which the number of the light sources 111 to which the light source parallel resistors 112 are connected in parallel is 4, the maximum current 724 is 600 mA, the maximum voltage 716 is 3.26 V, the minimum current 723 is 20 mA, and the minimum voltage 715 is 2 It is assumed that the minimum visual current 722 is 100 μA, the minimum visual voltage 714 is 2.4 V, and the resistance value R of the light source parallel resistor 112 is 10 kΩ. In that case, the voltage 720 is 22.82 V (= 3.26 V × 7), the voltage 719 is 18.48 V (= 2.64 V × 7), and the voltage 717 is 11.2 V (= 10 kΩ × 100 μA × 4 + 2.4 V × 3). )become.

FIG. 7 is a timing chart showing an example of the voltage / current of the light source circuit 100 in this embodiment.
The horizontal axis indicates time. The vertical axis represents voltage or current. A voltage 713 indicated by a solid line indicates a voltage across the smoothing capacitor C28 of the power supply circuit 821, that is, a voltage across the light source circuit 100. A current 725 and a current 726 indicated by solid lines indicate a current flowing through the light source circuit 100. A current 727 and a current 728 indicated by broken lines indicate a current flowing through the light source 111 of the light source circuit 100 to which the light source parallel resistor 112 is connected in parallel. The current 726 and the current 728 are enlarged in the vertical axis to show a case where the current is very small. Note that the current 727 almost overlaps with the current 725.
A current 729 indicated by a solid line indicates a current flowing through the light source circuit of the comparative example. The light source circuit of the comparative example is a circuit that does not have the light source parallel resistor 112 but simply has the light sources 111 connected in series.
Note that the conduction angle is the minimum conduction angle.

At time 734 indicated by the vertical axis, the supply of power to the lighting device 820 is started, and the voltage across the light source circuit 100 gradually increases.
At time 735 indicated by a broken line, the voltage 713 across the light source circuit 100 reaches the voltage 717, and the current flowing through the light source circuit 100 reaches the minimum visual current 722. Thereby, the user visually recognizes that the lighting device 820 is turning on.
At a time 736 indicated by a broken line, the voltage 713 across the light source circuit 100 reaches the minimum visible voltage 718, and the current flowing through the light source 111 connected to the light source parallel resistor 112 also reaches the minimum visible current 722.
Thereafter, the voltage 713 across the light source circuit 100 approaches the voltage 719, and the current 727 flowing through the light source circuit 100 approaches the minimum current 723. Thereby, the light source 111 of the illuminating device 820 lights with predetermined brightness.

On the other hand, in the comparative example, the current flowing through the light source circuit reaches the minimum visual current 722 at time 737 that is later than time 735. At this time, the voltage across the light source circuit is

For example, according to the numerical example described above, since the minimum visual recognition voltage 714 is 2.4 V, the voltage across the light source circuit at this time is 16.8 V (= 2.4 V × 7).
That is, in the case of the comparative example, if the voltage across the smoothing capacitor C28 does not reach 16.8V, the user cannot recognize that the lighting device 820 is being turned on. When the voltage across the capacitor C28 reaches 11.2V, the user can recognize that the lighting device 820 is turning on. Therefore, it is possible to shorten the time taken from when the power is turned on until the user recognizes that the lighting device 820 is turning on.

Since the user cannot recognize that the lighting device 820 is lit until the current flowing through the light source 111 reaches the minimum visible current 722 after the power is turned on, if this time is too long, the user Is recognized as a failure or reaction delay.
In the lighting device 820 in this embodiment, the time taken for the current flowing through the light source 111 to which the light source parallel resistor 112 is not connected in parallel to reach the minimum visual current 722 is shortened. It can prevent being misidentified.

ただし、Ｐ_Ｒは、光源並列抵抗１１２における電力損失を示す。Ｖ_Ｆｍａｘは、光源１１１を流れる電流が最大電流７２４であるときの光源１１１の両端電圧７１６である。 Note that, since the current always flows through the light source parallel resistor 112 while the lighting device 820 is turned on, a power loss in the light source parallel resistor 112 occurs. The power loss in the light source parallel resistor 112 is maximized when the conduction angle is the maximum conduction angle. The maximum value of power loss in the light source parallel resistor 112 is expressed by the following equation.

However, _{P R} represents the power loss in the light source parallel resistor 112. V _Fmax is a voltage 716 across the light source 111 when the current flowing through the light source 111 is the maximum current 724.

  As apparent from Equation 11, the smaller the resistance value R of the light source parallel resistor 112 is, the smaller the minimum visual recognition voltage 718 is. Therefore, the time required for the user to recognize that the lighting device 820 is being turned on is short. Become. On the other hand, as apparent from Equation 15, when the resistance value R of the light source parallel resistor 112 is small, the power loss in the light source parallel resistor 112 increases.

ただし、Ｐ_ｍａｘは、最大許容損失電力である。最大許容損失電力Ｐ_ｍａｘは、例えば１ｍＷなど、光源１１１における消費電力と比較して非常に小さい値に設定する。あるいは、最大許容損失電力Ｐ_ｍａｘは、光源１１１における消費電力に対する比（例えば１０００分の１）という形式で設定してもよい。例えば、上述した数値例によれば、最大電流が６００ｍＡ、最大電圧が３．２６Ｖだから、１つの光源１１１における消費電力は１．９６Ｗ（＝３．２６Ｖ×６００ｍＡ）である。したがって、最大許容損失電力Ｐ_ｍａｘは、例えば、１．９６ｍＷに設定する。
例えば、最大許容損失電力Ｐ_ｍａｘを１ｍＷに設定した場合、上記の数値例によれば、光源並列抵抗１１２の抵抗値Ｒは、１０．６３ｋΩ（＝３．２６Ｖ×３．２６Ｖ／１ｍＷ）以上の値に設定する。 Therefore, two parameters are set in advance, and the resistance value R of the light source parallel resistor 112 is determined according to the set parameters.
One is the maximum allowable loss power allowable as the power loss in the light source parallel resistor 112. That is, the resistance value R of the light source parallel resistor 112 is determined so as to satisfy the following expression.

Here, P _max is the maximum allowable power loss. The maximum allowable power loss P _max is set to a very small value compared to the power consumption in the light source 111, for example, 1 mW. Alternatively, the maximum allowable loss power P _max may be set in the form of a ratio (for example, 1/1000) to the power consumption in the light source 111. For example, according to the numerical example described above, since the maximum current is 600 mA and the maximum voltage is 3.26 V, the power consumption in one light source 111 is 1.96 W (= 3.26 V × 600 mA). Accordingly, the maximum allowable loss power P _max is set to 1.96 mW, for example.
For example, when the maximum allowable power loss P _max is set to 1 mW, according to the above numerical example, the resistance value R of the light source parallel resistor 112 is 10.63 kΩ (= 3.26 V × 3.26 V / 1 mW) or more. Set to value.

ただし、Ｔ_ｍａｘは、最大許容点灯時間である。最大許容点灯時間Ｔ_ｍａｘは、例えば４００ミリ秒など、５００ミリ秒以下の値に設定する。５００ミリ秒以上の遅延があると、利用者が違和感を感じるからである。Ｖ_ｏｕｔ（Ｔ_ｍａｘ）は、電源投入から最大許容点灯時間Ｔ_ｍａｘが経過した時点において、電源回路８２１が生成する直流電力の電圧値（平滑コンデンサＣ２８の両端電圧）である。
なお、Ｖ_ｏｕｔ（Ｔ_ｍａｘ）は、光源回路１００を流れる電流によって変化する。このため、光源並列抵抗１１２の抵抗値Ｒの計算にあたっては、光源回路１００を流れる電流が０である場合（すなわち、電源回路８２１の負荷である光源回路１００が接続されていない場合）における値を用いる。
例えば、Ｔ_ｍａｘを４００ミリ秒に設定し、Ｖ_ｏｕｔ（Ｔ_ｍａｘ）が１２Ｖである場合、上記の数値例によれば、光源並列抵抗１１２の抵抗値Ｒは、１２ｋΩ［＝（１２Ｖ−２．４Ｖ×３）／（１００μＡ×４）］以下の値に設定する。 Another parameter is the maximum allowable lighting time that can be allowed as the time it takes for the user to recognize that the lighting device 820 is lighting after the power is turned on. That is, the resistance value R of the light source parallel resistor 112 is determined so as to satisfy the following expression.

However, T _max is the maximum allowable lighting time. The maximum allowable lighting time T _max is set to a value of 500 milliseconds or less, such as 400 milliseconds. This is because the user feels uncomfortable when there is a delay of 500 milliseconds or more. V _out (T _max ) is the voltage value of the DC power (the voltage across the smoothing capacitor C28) generated by the power supply circuit 821 when the maximum allowable lighting time T _max has elapsed since the power was turned on.
Note that V _out (T _max ) varies depending on the current flowing through the light source circuit 100. Therefore, in calculating the resistance value R of the light source parallel resistor 112, the value when the current flowing through the light source circuit 100 is 0 (that is, when the light source circuit 100 that is the load of the power supply circuit 821 is not connected) is used. Use.
For example, when T _max is set to 400 milliseconds and V _out (T _max ) is 12 V, according to the above numerical example, the resistance value R of the light source parallel resistor 112 is 12 kΩ [= (12 V−2. 4V × 3) / (100 μA × 4)].

  The resistance value R of the light source parallel resistor 112 is determined so as to satisfy the above two expressions. For example, according to the above numerical example, the resistance value R of the light source parallel resistor 112 is set to a value of 10.63 kΩ or more and 12 kΩ or less.

  Thereby, it is possible to suppress power loss while preventing the user from misidentifying it as a failure or a reaction delay.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIG.
In addition, about the part which is common in Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 8 is a circuit diagram showing a circuit configuration of illumination device 820 in this embodiment.
The lighting device 820 includes a discharge circuit 823 in addition to the power supply circuit 821 and the light source circuit 100 described in Embodiment 1.
The discharge circuit 823 discharges the smoothing capacitor C28 when the power is turned off. The discharge circuit 823 includes, for example, a power failure detection circuit 824, a photocoupler PC, a gate resistor R31, a discharge resistor R32, and a thyristor T33. The power failure detection circuit 824, for example, monitors the voltage waveform of the power that is full-wave rectified by the diode bridge DB, and determines whether or not the power supply from the AC power supply AC to the lighting device 820 is stopped. The power failure detection circuit 824 generates a pulse for lighting the light emitting diode of the photocoupler PC when detecting the stop of the power supply.
The emitter terminal of the phototransistor of the photocoupler PC is electrically connected to one end of the gate resistor R31 and the gate terminal of the thyristor T33. The other end of the gate resistor R31 and the cathode terminal of the thyristor T33 are electrically connected to the cathode side terminal of the smoothing capacitor C28. The collector terminal of the phototransistor of the photocoupler PC and one end of the discharge resistor R32 are electrically connected to the anode side terminal of the smoothing capacitor C28. The other end of the discharge resistor R32 is electrically connected to the anode terminal of the thyristor T33.
When the light emitting diode of the photocoupler PC is turned on by the pulse generated by the power failure detection circuit 824, the phototransistor is turned on, a current flows through the gate resistor R31, the potential of the gate terminal of the thyristor T33 is increased, and the thyristor T33 is Turn on. When the thyristor T33 is turned on, a current for discharging the smoothing capacitor C28 flows through the discharge resistor R32. The discharge resistor R32 limits the current that discharges the smoothing capacitor C28. When the smoothing capacitor C28 finishes discharging, the current flowing through the thyristor T33 becomes 0, and the thyristor T33 is turned off.

  Even if the user turns off the power switch and stops supplying power to the lighting device 820, the light source 111 is lit while the charge stored in the smoothing capacitor C28 remains. In particular, the light source 111 to which the light source parallel resistor 112 is not connected in parallel is lit even when the voltage across the smoothing capacitor C28 is low, and therefore, there is a high possibility that the light source 111 will remain unlit.

  Therefore, the illumination device 820 of this embodiment discharges the smoothing capacitor C28 in a short time when the power supply to the illumination device 820 is stopped. As a result, it is possible to prevent the light source 111 from remaining off.

Embodiment 3 FIG.
The third embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1- Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 9 is a front view showing the shape of the light source module 110 in this embodiment.
The light source module 110 does not have the light source parallel resistance 112, and only the plurality of light sources 111 are mounted on the substrate 115.

FIG. 10 is a circuit diagram showing a circuit configuration of illumination device 820 in this embodiment.
The light source module 110 has two circuits in which light sources 111 are connected in series. The light source circuit 100 includes a light source module 110 and a light source parallel resistor 112. The light source parallel resistor 112 is electrically connected in parallel with a circuit in which the light sources 111a to 111d are connected in series.

As described above, the light source parallel resistor 112 may be connected in parallel to a circuit in which a plurality of light sources 111 are connected in series, instead of being connected in parallel to one light source 111 one by one.
Further, by providing the light source parallel resistor 112 separately from the light source module 110, it is possible to prevent the light source 111 from being affected by heat generated by power loss in the light source parallel resistor 112, and to suppress the temperature rise of the light source 111. it can.

Embodiment 4 FIG.
The fourth embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1- Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 11 is a circuit diagram showing a circuit configuration of illumination device 820 in this embodiment.
The light source circuit 100 includes a light source parallel capacitor 113 (light source parallel impedance) instead of the light source parallel resistor 112 of the third embodiment. The light source parallel capacitor 113 may be configured to be connected in parallel to one light source 111 one by one, similar to the light source parallel resistor 112 described in the first to second embodiments. Further, the light source parallel capacitor 113 is not provided separately from the light source module 110 but may be configured to be mounted on the light source module 110.

FIG. 12 is a timing chart showing an example of the voltage / current of the light source circuit 100 in this embodiment.
The horizontal axis indicates time. The vertical axis represents voltage or current. A voltage 713 indicated by a solid line indicates a voltage across the smoothing capacitor C28 of the power supply circuit 821, that is, a voltage across the light source circuit 100. A current 725 and a current 726 indicated by solid lines indicate a current flowing through the light source circuit 100. A current 727 and a current 728 indicated by a broken line indicate a current flowing through the light source 111 of the light source circuit 100 to which the light source parallel resistor 112 is connected in parallel. The current 726 and the current 728 are enlarged in the vertical axis to show a case where the current is very small. Note that the current 727 almost overlaps with the current 725.
Note that the conduction angle is the minimum conduction angle.

ただし、Ｉは、光源並列コンデンサ１１３を充電する電流である。Ｃは、光源並列コンデンサ１１３の静電容量である。Ｃ_ｏｕｔは、平滑コンデンサＣ２８の静電容量である。Ｉ_ｏｕｔは、平滑コンデンサＣ２８を充電する電流である。 At time 734 indicated by the vertical axis, the voltage across the smoothing capacitor C28 and the light source parallel capacitor 113 is almost zero. When the supply of power to the lighting device 820 is started, the voltage across the light source circuit 100 gradually increases. The current flowing through the light source parallel capacitor 113 is the same as the current flowing through the light sources 111e to 111g. The voltage across the circuit in which the light sources 111e to 111g are connected in series is equal to the difference obtained by subtracting the voltage across the light source parallel capacitor 113 from the voltage across the smoothing capacitor C28. Initially, since the voltage across the smoothing capacitor C28 is low, no current flows through the light sources 111e to 111g, and the voltage across the light source parallel capacitor 113 remains zero. As a result, the voltage at both ends of the circuit in which the light sources 111e to 111g are connected in series increases, and current starts to flow through the light sources 111e to 111g. As a result, the voltage across the light source parallel capacitor 113 also starts to rise.
The rising width of the voltage across the light source parallel capacitor 113 is substantially equal to the rising width of the voltage across the smoothing capacitor C28. This is because when more current flows through the light source parallel capacitor 113, the voltage across the circuit where the light sources 111e to 111g are connected in series decreases, so that the current flowing through the light sources 111e to 111g decreases. When less current flows through the light source parallel capacitor 113, the voltage across the circuit in which the light sources 111e to 111g are connected in series increases, so that the current flowing through the light sources 111e to 111g increases. At this time, since the current flowing through the light source parallel capacitor 113 has almost the same increase in the voltage at both ends,

Here, I is a current for charging the light source parallel capacitor 113. C is the capacitance of the light source parallel capacitor 113. C _out is the capacitance of the smoothing capacitor C28. I _out is a current for charging the smoothing capacitor C28.

ただし、Ｉ_ｍｉｎは、最小電流７２３である。 And the current I for charging the light source parallel capacitor 113, the sum of the current I _out to charge the smoothing capacitor C28 is approximately equal to the current supplied from the secondary winding L26. When the conduction angle is the minimum conduction angle, the current supplied from the secondary winding L26 is substantially equal to the minimum current 723.

However, I _min is the minimum current 723.

If the current I for charging the light source parallel capacitor 113 is larger than the minimum visual current 722, the user can visually recognize that the lighting device 820 is being turned on. A capacity C is set.

  For example, when the capacitance of the smoothing capacitor C28 is 3300 μF, according to the numerical example used in the first embodiment, the capacitance C of the light source parallel capacitor 113 is 16.6 μF (= 100 μA / (20 mA−100 μA). ) × 3300 μF) or more.

  By setting the capacitance C of the light source parallel capacitor 113 so as to satisfy this equation, the current flowing through the light source circuit 100 exceeds the minimum visible current 722 at time 735 indicated by a broken line. Thereby, the user visually recognizes that the lighting device 820 is turning on.

Thereafter, the voltage across the light source parallel capacitor 113 rises, and at time 736 indicated by a broken line, the voltage across the circuit in which the light sources 111a to 111d are connected in series exceeds the sum of the minimum visual recognition voltages 714. Thereby, the current flowing through the light source 111 to which the light source parallel resistor 112 is connected also reaches the minimum visual current 722.
Thereafter, the voltage 713 across the light source circuit 100 approaches the voltage 719, and the current 727 flowing through the light source circuit 100 approaches the minimum current 723. Thereby, the light source of the illuminating device 820 lights with predetermined brightness.

  Thus, since the time taken for the current flowing through the light source 111 not connected in parallel to the light source parallel capacitor 113 to reach the minimum visible current 722 is shortened, the user is prevented from being mistaken as a failure or a reaction delay. be able to.

  In addition, after the transient period at the time of turning on the power, the light source parallel capacitor 113 is sufficiently charged, so that the current flowing through the light source parallel capacitor 113 becomes almost zero. Unlike the case where the light source parallel resistor 112 is connected, there is no power loss, so that the power efficiency of the lighting device 820 can be increased.

Further, when the light is turned off (when the power is shut off), the light source parallel capacitor 113 is charged, so that the light sources 111a to 111d can be turned on for a certain period of time.
When the discharge circuit 823 described in the second embodiment is connected in parallel with the smoothing capacitor C28, it is preferable to connect the discharge circuit to the light source parallel capacitor 113 in parallel. Then, not only the light sources 111a to 111d can be turned off immediately, but also when the power is turned on immediately after the power is turned off, the light source parallel capacitor 113 is discharged, so that the light sources 111e to 111g are replaced by the light sources 111a to 111d. Can also be turned on first.

Embodiment 5 FIG.
A fifth embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1- Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 13 is a circuit diagram showing a circuit configuration of illumination device 820 in this embodiment.
The light source circuit 100 includes a series circuit (light source parallel impedance) of the light source parallel resistor 112 and the light source parallel capacitor 113 instead of the light source parallel resistor 112 of the third embodiment and the light source parallel capacitor 113 of the fourth embodiment.

FIG. 14 is a timing chart showing an example of the voltage / current of the light source circuit 100 in this embodiment.
The horizontal axis indicates time. The vertical axis represents voltage or current. A voltage 713 indicated by a solid line indicates a voltage across the smoothing capacitor C28 of the power supply circuit 821, that is, a voltage across the light source circuit 100. A current 725 and a current 726 indicated by solid lines indicate a current flowing through the light source circuit 100. A current 727 and a current 728 indicated by broken lines indicate a current flowing through the light source 111 of the light source circuit 100 to which the light source parallel resistor 112 is connected in parallel. The current 726 and the current 728 are enlarged in the vertical axis to show a case where the current is very small.
Note that the conduction angle is the minimum conduction angle.

In this example, the resistance value R of the light source parallel resistor 112 is considerably smaller than the resistance value described in the first embodiment. Further, the capacitance C of the light source parallel capacitor 113 is approximately the same as the capacitance of the smoothing capacitor C28.
Thereby, before the light sources 111a to 111d in which the series circuit of the light source parallel resistor 112 and the light source parallel capacitor 113 are connected in parallel start lighting, the series circuit of the light source parallel resistor 112 and the light source parallel capacitor 113 are connected in parallel. The electric current which flows through the light sources 111e-111g which are not performed becomes large. For this reason, a user not only recognizes that the lighting device 820 is turning on, but can also apply a fade-in effect to the lighting device 820.

  As in the fourth embodiment, the light source parallel capacitor 113 is sufficiently charged after the transition period at the time of turning on the power, so that the current flowing through the light source parallel capacitor 113 becomes almost zero. For this reason, the current flowing through the light source parallel resistor 112 connected in series with the light source parallel capacitor 113 becomes almost zero, and the power loss in the light source parallel resistor 112 becomes almost zero. For this reason, the power efficiency of the illuminating device 820 can be improved.

Embodiment 6 FIG.
The sixth embodiment will be described.
In addition, about the part which is common in Embodiment 1- Embodiment 5, the same code | symbol is used and description is abbreviate | omitted.

  In the light source circuit 100 in this embodiment, the light source 111 emits so-called white light. Among the light sources 111, the light source 111 that is not connected in parallel with the light source parallel impedance (the light source parallel resistor 112 or the light source parallel capacitor 113 or the series circuit of the light source parallel resistor 112 and the light source parallel capacitor 113) has the light source parallel impedance connected in parallel. It emits light having a correlated color temperature lower than that of the light source 111. For example, the light source color of the light source 111 whose light source parallel impedance is not connected in parallel is “bulb color” defined in Japanese Industrial Standard Z9112: 2004 “Division by light source color and color rendering property of fluorescent lamp”. The light source color of the light sources 111 connected in parallel is “day white”. Alternatively, the correlated color temperature of the light source 111 whose light source parallel impedance is not connected in parallel is, for example, 3000K, and the correlated color temperature of the light source 111 whose light source parallel impedance is connected in parallel is, for example, 5000K.

  Immediately after the power is turned on, only the light source 111 whose light source parallel impedance is not connected in parallel is lit. Accordingly, the lighting device 820 emits light having a low correlated color temperature. Thereafter, the light source 111 connected in parallel with the light source parallel impedance is also turned on. Therefore, the light emitted from the lighting device 820 is a mixture of light having a low correlated color temperature and light having a high correlated color temperature, and has a correlated color temperature between them.

  In general, it is known that when the correlated color temperature of the light source is low, the room becomes a hot atmosphere, and when the correlated color temperature is high, a negative atmosphere is obtained. The right correlated color temperature that makes the room feel comfortable depends on the illuminance. When the illuminance is low, the correlated color temperature is comfortable with a low correlated color temperature, whereas when the illuminance is high, the correlated color temperature is comfortable with a high correlated color temperature. (Willoughby curve).

  The light source circuit 100 in this embodiment has a low correlated color temperature of emitted light when the output immediately after the start of lighting is low, and the correlated color temperature increases when the output increases thereafter. Thereby, a comfortable atmosphere can always be maintained, there is no sense of incongruity at the time of lighting, and a high production effect can be obtained.

  As described above, the configuration described in each embodiment is an example, and may be a configuration in which configurations described in different embodiments are combined, a configuration in which an unimportant part is replaced with a known configuration, or the like.

The light source circuit / illumination apparatus / illumination system described above has a feeling of incongruity in turning on and off the power switch because the delay time from power-on is shortened even with low dimming lighting. In addition, a fade-in effect can be obtained in which the light output from the LED gradually increases when the power is turned on.
When the power is turned off, it is possible to obtain a fade-out effect in which the light output gradually decreases, and by providing the discharge circuit 823, the turn-off time can be shortened and the light can be turned off immediately.

  100 light source circuit, 110 light source module, 111 light source, 112 light source parallel resistance, 113 light source parallel capacitor, 115 substrate, 711-720 voltage, 721-728 current, 731-737 time, 741-746 characteristics, 800 illumination system, 810 phase Control dimmer, 811 dimming input unit, 812 bidirectional thyristor, 813 drive circuit, 820 lighting device, 821 power supply circuit, 822 control circuit, 823 discharge circuit, 824 power failure detection circuit, AC AC power supply, C28 smoothing capacitor, D27 Diode, DB Diode bridge, L25 primary winding, L26 secondary winding, PC photocoupler, Q23 switching element, T24 transformer, T33 thyristor, R31 gate resistance, R32 discharge resistance.

Claims (7)

In the light source circuit of the lighting device that is lit by the AC power phase-controlled according to the specified dimming degree,
A plurality of light emitting diodes electrically connected in series;
Have a light source parallel impedance which is electrically connected in parallel to one of the plurality of light emitting diodes,
The light source parallel impedance is a resistor having a resistance value satisfying the following formula:

Here, R is the resistance value of the resistor which is the light source parallel impedance. V _Fmax is a forward voltage drop when a predetermined maximum current is passed through a light emitting diode having the light source parallel impedance connected in parallel. P _max is the maximum allowable loss power allowed as a loss in the light source parallel impedance. 2. The light source circuit according to claim 1, wherein at least one of the light emitting diodes not connected in parallel with the light source parallel impedance has a correlated color temperature lower than that of the light emitting diode connected in parallel with the light source parallel impedance.   In the light source circuit of the lighting device that is lit by the AC power phase-controlled according to the specified dimming degree,
  A plurality of light emitting diodes electrically connected in series;
  Light source parallel impedance electrically connected in parallel to any of the plurality of light emitting diodes
And
  The light source circuit, wherein at least one of the light emitting diodes whose light source parallel impedance is not connected in parallel has a correlated color temperature lower than that of the light emitting diode whose light source parallel impedance is connected in parallel. A light source circuit according to any one of claims 1 to 3,
A lighting apparatus comprising: a power supply circuit that receives phase-controlled AC power and generates DC power to be supplied to the light source circuit from the input AC power. The illumination device according to claim 4, wherein the light source parallel impedance is a resistor having a resistance value satisfying the following expression.

However, I _v is the minimum viewing current emitting diodes the light source parallel impedance is not connected in parallel is visible and illuminated. V _Fv is a forward voltage drop when the minimum visible current is passed through a light emitting diode whose light source parallel impedance is not connected in parallel. T _max is a maximum allowable lighting time that is allowed as a time required from when the power supply circuit starts to input the AC power to when it is recognized that at least one of the plurality of light emitting diodes is turned on. V _out (T _max ) is the maximum allowable lighting time after the power supply circuit starts inputting the AC power when the phase angle of the AC power input by the power supply circuit is a predetermined minimum phase angle. This is the voltage value of the DC power generated by the power supply circuit when it has elapsed. The power circuit is
It has a smoothing capacitor that smoothes the voltage value of the generated DC power,
The lighting device is
6. The lighting device according to claim 4, further comprising a discharge circuit that discharges the smoothing capacitor when the power supply circuit stops the input of the AC power. A phase control dimmer for controlling the phase of the AC power supplied from the AC power source according to the specified dimming rate;
The lighting system according to any one of claims 4 to 6, wherein the phase control dimmer inputs phase-controlled electric power.

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