JP2012015052A - Lighting device and illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device capable of stably lighting a light-emitting diode even at a low temperature by restricting a capacity drop of an electrolytic capacitor at a low temperature using a simple method to prevent blinking or flickering of the light-emitting diode.SOLUTION: A lighting device is provided, in which: a timer circuit section 180 detects the lapse of a predetermined initial time which is set as a time for sufficiently recovering a capacitance drop of an electrolytic capacitor C1 at a low temperature by the heat generation of the electrolytic capacitor C1; and a lighting control circuit section 170 allows a lighting circuit section 140 to output an initial amount of current smaller than a target amount of current until the initial time elapses, and thereafter allows the lighting circuit section 140 to output the target amount of current so as to light a light-emitting diode section 160. The initial amount of current is determined so that a voltage applied to the light-emitting diode section 160 is not lower than a forward drop voltage thereof even when the capacitance of the electrolytic capacitor C1 drops at a low temperature.

Description

  The present invention relates to a lighting device and a lighting device that light a light source in a low temperature environment, for example.

  Conventionally, a light emitting diode lighting device performs voltage control so that the voltage applied to the light emitting diode is lowered when the temperature is increased based on the temperature information acquired from the thermistor, and the voltage applied to the light emitting diode is increased when the temperature is lowered. It was. This stabilizes the color temperature and luminance of the light emitting diode (for example, Patent Document 1).

  In recent years, with the widespread use of light-emitting diode lighting, a lighting device using a light source such as a light-emitting diode that can be used at a low temperature in a freezer warehouse or the like has been required. This is because the number of light sources such as light emitting diodes with good rising characteristics of light beams at low temperatures has increased.

International Publication No. 2010/044300 Pamphlet

An electrolytic capacitor is often used inside the light emitting diode lighting device, and it is known that the electrolytic capacitor freezes at low temperatures, causing a decrease in capacity.
For this reason, the subject that the light emitting diode blinks or flickers by the capacity | capacitance fall of the electrolytic capacitor under low temperature occurred.
Also, in the buck converter type lighting circuit, the capacitance of the electrolytic capacitor on the input side decreases and the ripple voltage increases, so that the potential is reversed between the output side and the input side of the lighting circuit, and the current flows backward. There was a problem that would break down.

  An object of the present invention is to cope with a decrease in the capacity of an electrolytic capacitor at a low temperature, for example, by a simple method, to prevent the light emitting diode from blinking and flickering, and to stably light the light emitting diode even at a low temperature. And

The lighting device of the present invention is a lighting device for lighting a light source.
A rectifier circuit that inputs an alternating current, rectifies the input alternating current, and outputs a pulsating current;
An electrolytic capacitor that changes capacitance according to temperature and smoothes a pulsating current output from the rectifier circuit unit into a direct current;
A lighting circuit unit that inputs a direct current obtained by the electrolytic capacitor and outputs an output current of a predetermined target current amount to a light source, and the temperature of the electrolytic capacitor after the alternating current is input to the rectifier circuit unit The output current smaller than the target current amount is output to the light source until a predetermined initial time for the capacitance of the electrolytic capacitor to reach a predetermined amount elapses, and the target current amount is passed after the initial time has elapsed. A lighting circuit unit that outputs the output current of the output to the light source.

  According to the present invention, for example, by flowing an initial current amount smaller than the target current amount to the light emitting diode of the light source until the electrolytic capacitor is warmed, the light emitting diode is prevented from blinking and flickering, and the light emitting diode is stably stabilized even at a low temperature. Can be lit.

FIG. 3 is a circuit block diagram of low-temperature LED lighting device 100 according to the first embodiment. 3 is a graph showing output current control of a lighting circuit unit 140 in the first embodiment. The graph which shows the temperature characteristic of the electrostatic capacitance and impedance of an electrolytic capacitor. 3 is a graph showing a voltage waveform of the electrolytic capacitor C1 immediately after activation of the low temperature LED lighting device 100 according to the first embodiment. 3 is a graph showing a voltage waveform of the electrolytic capacitor C2 immediately after the start of the low temperature LED lighting device 100 according to the first embodiment. 3 is a graph showing a voltage waveform of electrolytic capacitor C1 of LED lighting device 100 for low temperature in the first embodiment. 6 is a graph showing output current control of a lighting circuit unit 140 according to Embodiment 2. 10 is a graph showing output current control of the lighting circuit section 140 in the third embodiment. FIG. 6 is a circuit block diagram of a low-temperature LED lighting device 100 according to a fourth embodiment.

Embodiment 1 FIG.
FIG. 1 is a circuit block diagram of LED lighting device 100 for low temperature in the first embodiment.
The LED lighting device 100 for low temperature in Embodiment 1 is demonstrated based on FIG.

The low-temperature LED lighting device 100 is used in a low-temperature environment / place such as in a freezer warehouse, and constitutes a low-temperature LED illumination device together with the light-emitting diode unit 160, an appliance body (not shown), and a switch device (not shown). .
The appliance main body houses the low-temperature LED lighting device 100 and the light-emitting diode unit 160.
When the switch device is turned on, power is supplied from the commercial power source, the low temperature LED lighting device 100 is activated, a current flows through each circuit, and the light emitting diode unit 160 is lit. When the switch device is turned off, power supply from the commercial power supply is stopped, the low temperature LED lighting device 100 is stopped, and the light emitting diode unit 160 is turned off.

  The LED lighting device 100 for low temperature includes an input filter circuit unit 110, a rectifier circuit unit 120, a power supply smoothing unit 130, a lighting circuit unit 140, an output smoothing unit 150, a light emitting diode unit 160, a lighting control circuit unit 170, and a timer circuit unit 180. Prepare.

  The input filter circuit unit 110 constitutes a noise filter and removes noise from the commercial power supply.

The rectifier circuit unit 120 receives an AC current / voltage of a commercial power supply, performs full-wave rectification on the input AC current / voltage, and outputs a pulsating current / voltage obtained by full-wave rectification.
For example, the rectifier circuit unit 120 is configured with a diode bridge.

The power supply smoothing unit 130 includes an electrolytic capacitor C1.
The power supply smoothing unit 130 charges the electrolytic capacitor C1 with the pulsating current output from the rectifying circuit unit 120, and discharges the charged charge from the electrolytic capacitor C1, thereby outputting the output current output from the rectifying circuit unit 120.・ Smooth the voltage.
For example, the power supply smoothing unit 130 is configured by a capacitor input type circuit configured only by the electrolytic capacitor C1 or a step-up chopper type active filter circuit.
Hereinafter, the power supply smoothing unit 130 will be described as a capacitor input type circuit including only the electrolytic capacitor C1.

The lighting circuit unit 140 is a circuit that inputs the DC current / voltage smoothed by the power supply smoothing unit 130, steps down the input DC voltage, and outputs an output current / voltage of a predetermined magnitude to the light emitting diode unit 160. .
For example, the lighting circuit unit 140 is configured by a back converter type or half bridge type circuit.

The output smoothing unit 150 includes an electrolytic capacitor C2.
Similar to the power supply smoothing unit 130, the output smoothing unit 150 smoothes the output current / voltage output from the lighting circuit unit 140.

The light emitting diode unit 160 is a plurality of light emitting diodes connected in series on the printed circuit board.
The light emitting diode unit 160 receives the output current / voltage smoothed by the output smoothing unit 150 and lights up with the input output current / voltage.

  The plurality of light emitting diodes of the light emitting diode unit 160 are lit with brightness according to the magnitude of the current when a voltage larger than a predetermined forward drop voltage is applied, and the applied voltage is smaller than the forward drop voltage. not light.

The timer circuit unit 180 counts the elapsed time since the low temperature LED lighting device 100 is activated, and detects the passage of a predetermined initial time.
The initial time is a waiting time for the electrolytic capacitors C1 and C2 whose capacitances have been lowered due to use in a low temperature environment to generate heat and raise the internal temperature, and to sufficiently recover the respective capacitances. is there.
The initial time is stored and set in advance in a storage circuit provided in the timer circuit unit 180.

The lighting control circuit unit 170 is a circuit that controls the lighting circuit unit 140 to adjust / change the magnitude of the output current of the lighting circuit unit 140.
For example, the lighting circuit unit 140 includes a switch element (for example, a transistor), and the lighting control circuit unit 170 performs switching control of the switch element of the lighting circuit unit 140. A current having a magnitude corresponding to the ratio of the ON time of the switch element flows through the lighting circuit section 140, and the lighting circuit section 140 outputs an output current / voltage having a magnitude corresponding to the current flowing through the circuit.

FIG. 2 is a graph showing the output current control of the lighting circuit unit 140 in the first embodiment.
The output current control of the lighting circuit unit 140 by the lighting control circuit unit 170 will be described with reference to FIG.

  In FIG. 2, the output current from the lighting circuit section 140 to the light emitting diode section 160 is indicated by a solid line, and the capacitance of the electrolytic capacitor C1 is indicated by a dotted line.

  The lighting control circuit unit 170 lights an output current of a predetermined initial current amount from when the low temperature LED lighting device 100 is activated (time T0) until the timer circuit unit 180 detects the passage of the initial time (time T1). The circuit part 140 is made to output. Then, the lighting control circuit unit 170 causes the lighting circuit unit 140 to output an output current of a predetermined target current amount after the timer circuit unit 180 detects the passage of the initial time (time T0).

The target current amount is a magnitude of a current necessary for lighting the light emitting diode unit 160 with a target brightness (for example, maximum brightness).
The initial current amount is a current that does not lower the output voltage applied to the light emitting diode unit 160 from the forward voltage of the light emitting diode unit 160 even if the capacitance of the electrolytic capacitors C1 and C2 is reduced due to use in a low temperature environment. Is the size of The initial current amount is smaller than the target current amount (for example, 50% of the target current amount).
Control information for causing the lighting circuit unit 140 to output the target current amount and the initial current amount (for example, the ratio of the ON time of the switch element) is stored and set in advance in a storage circuit provided in the lighting control circuit unit 170.

  The “initial time” and “initial current amount” will be described below.

FIG. 3 is a graph showing temperature characteristics of capacitance and impedance of the electrolytic capacitor. The temperature characteristics of the capacitance and impedance of the electrolytic capacitor will be described with reference to FIG. 3, taking an aluminum electrolytic capacitor BXC450V15 μF as an example.
In FIG. 3, a solid line indicates a value disclosed by a manufacturer, and a broken line indicates an estimated value.

When the electrolytic capacitor is used at a low temperature, the internal electrolytic solution is frozen, so that the capacitance is reduced while the internal impedance is increased.
For example, the capacitance of the electrolytic capacitor decreases to 60% at room temperature (20 degrees) at -40 degrees, and to 20% at room temperature at -60 degrees.
On the other hand, the internal impedance of the electrolytic capacitor increases to 600% at normal temperature at −40 degrees, and increases to 1200% at normal temperature at −60 degrees.

In this way, the capacitance of the electrolytic capacitor decreases at low temperatures.
That is, immediately after the start of the low temperature LED lighting device 100, the temperature of each electrolytic capacitor C1, C2 is low, and the capacitance is reduced. For this reason, each of the electrolytic capacitors C1 and C2 immediately after startup cannot be charged with a sufficient amount of charge, and the output voltage applied to the light emitting diode section 160 cannot be sufficiently smoothed.

FIG. 4 is a graph showing a voltage waveform of the electrolytic capacitor C1 immediately after the start of the low temperature LED lighting device 100 according to the first embodiment.
FIG. 5 is a graph showing a voltage waveform of the electrolytic capacitor C2 immediately after activation of the low temperature LED lighting device 100 according to the first embodiment.
A voltage waveform of electrolytic capacitors C1 and C2 immediately after startup of LED lighting device 100 for low temperature in the first embodiment will be described based on FIGS.

The output voltage (rectified voltage) of the rectifier circuit unit 120 is indicated by a one-dot chain line, and the output voltages (smooth voltage) of the electrolytic capacitors C1 and C2 are indicated by a solid line.
The smoothing voltage of the electrolytic capacitor C1 is obtained by smoothing the output of the rectifier circuit unit 120.
The smoothing voltage of the electrolytic capacitor C <b> 2 is equal to the voltage applied to the light emitting diode unit 160.

The electrolytic capacitor C1 smoothes the rectified voltage of the rectifier circuit unit 120 as shown in FIG.
However, since the capacitance of the electrolytic capacitor C1 immediately after startup is low, the rectified voltage cannot be sufficiently smoothed, and the ripple voltage ΔV of the smoothed voltage is large. The ripple voltage ΔV is the magnitude of the pulsating flow component of the smooth voltage. That is, the difference between the maximum voltage (peak voltage VACp) of the smoothing voltage and the minimum voltage is the ripple voltage ΔV. The ripple voltage ΔV increases as the load current flowing through the light emitting diode unit 160 increases, and decreases as the load current decreases.
For this reason, when the current (load current) output from the lighting circuit section 140 to the light emitting diode section 160 is large, the time period (t1 to t2) when the smoothing voltage of the electrolytic capacitor C1 is lower than the forward voltage drop Vf of the light emitting diode section 160. Occurs. Since the capacity of the electrolytic capacitor C2 is also reduced, the electrolytic capacitor C2 also falls below the forward voltage drop Vf of the light emitting diode portion 160 during the time period from t1 to t2, as shown in FIG. Then, the light emitting diode unit 160 is turned off during the time period, and the light emitting diode unit 160 blinks or flickers. If the ripple voltage ΔV is equal to or lower than ΔV ′, the light emitting diode unit 160 does not blink or flicker.

  The initial current amount ILED that prevents the light emitting diode unit 160 from blinking or flickering by setting the ripple voltage ΔV to be equal to or lower than ΔV ′ can be obtained as follows.

Since the amount of charge Q charged in the electrolytic capacitor C1 may be equal to or greater than the amount of charge discharged when the current of the initial current amount ILED flows, the following equation (1) may be satisfied.
However, C1 shows the electrostatic capacitance of the electrolytic capacitor C1, and VACp shows the peak voltage of a power supply voltage, a rectification voltage, and a smoothing voltage. Further, t1 ′ indicates a time when the rectified voltage falls below the forward voltage drop Vf, and t2 indicates a time when the rectified voltage exceeds the forward voltage Vf.

  Q = C1 × (VACp−Vf) ≧ ILED × (t2−t1 ′) Formula (1)

  Therefore, the initial current amount ILED can be obtained by the following formula (2) based on the above formula (1).

  ILED ≦ C1 × (VACp−Vf) / (t2−t1 ′) Formula (2)

Further, the times “t1 ′” and “t2” can be obtained as “t” that satisfies the following relational expression (3).
However, V shows a power supply voltage, f shows the frequency of a power supply voltage, a rectification voltage, and a smoothing voltage.

  V = VACp × sin (2 × π × f × t) = Vf Equation (3)

  For example, when an electrolytic capacitor C1 having a capacitance of “20 μF” at normal temperature is used in an environment of “−60 degrees”, the capacitance C1 is “4 μF corresponding to 20% at normal temperature (see FIG. 3). (Equation (4)).

  C1 = 20 μF × 0.2 = 4 μF (4)

  Further, when the peak voltage VACp of the power supply voltage V is “141 V”, the frequency f of the power supply voltage V is “50 Hz”, and the forward voltage drop Vf of the light emitting diode section 160 is “50 V”, the above formula ( By substituting each value into 3), the following relational expression (5) is obtained.

  V = 141 × sin (2 × π × 50 × t) = 50 Formula (5)

  Based on t satisfying the relational expression (5), “(t2−t1 ′) = 2.3 ms” is obtained.

Then, when each obtained value is substituted into the above formula (2), “158 mA” is obtained as the maximum value of the initial current amount ILED (formula (6)).
Therefore, if the initial current amount ILED is set to “158 mA” or less under the above conditions, the light-emitting diode unit 160 can be prevented from blinking or flickering.

  ILED ≦ 4 μF × (141 V−50 V) / (2.3 ms) = 158 mA Formula (6)

FIG. 6 is a graph showing a voltage waveform of the electrolytic capacitor C1 of the low-temperature LED lighting device 100 according to the first embodiment.
An initial time T1 for outputting the initial current amount ILED from the lighting circuit section 140 to the light emitting diode section 160 in the first embodiment will be described with reference to FIG.

6A and 6B show voltage waveforms of the electrolytic capacitor C1 when the amount of current output from the lighting circuit portion 140 to the light emitting diode portion 160 is set to “150 mA” smaller than the initial current amount ILED “158 mA”. ing.
The horizontal axis of FIG. 6A shows time in the range of 500 ms / DIV, the horizontal axis of FIG. 6B shows time in the range of 5 s / DIV, and the vertical axis of FIGS. The voltage is shown in the range of 50V / DIV.

In an environment where the ambient temperature is -60 degrees, the capacitance of the electrolytic capacitor C1 is about 20% of that at room temperature (see FIG. 3), so the ripple voltage ΔV of the smoothing voltage is large.
On the other hand, since the internal impedance of the electrolytic capacitor C1 is about 1200% at room temperature (see FIG. 3), the calorific value (self-heating) is large, and the frozen electrolyte is gradually thawed.
Therefore, as time elapses, the electrolytic solution is thawed, the capacitance of the electrolytic capacitor C1 is restored, and the ripple voltage ΔV is reduced.

  The capacitance of the electrolytic capacitor C1 changes in the same manner as a curve (one-dot chain line) connecting the lower limit values of the smoothing voltage of the electrolytic capacitor C1.

  In FIG. 6 (b), the capacitance of the electrolytic capacitor C1 is about 80% of the capacitance (capacitance at room temperature) after about 20 seconds when the ripple voltage ΔV is stabilized after about 2.5 seconds. It turns out to recover.

Therefore, in the above condition, the initial time T1 of about “2.5 seconds” (for example, in the range of 2.0 seconds to 3.0 seconds) is set to the initial value of about “150 mA” (for example, in the range of 148 mA to 158 mA). The amount of current ILED may be output.
If the capacitance recovers to about 80% of the rated capacitance, the smoothing voltage of the electrolytic capacitor C1 can be maintained even if the amount of current that causes the light emitting diode portion 160 to light 100% is output from the lighting circuit portion 140. This is because it is considered not to fall below the forward voltage drop Vf.

For example, the life of an electrolytic capacitor is defined on the condition that 64% of the rated capacitance (capacitance at normal temperature) is used, and a circuit using an electrolytic capacitor generally has this capacitance value of “64%”. Designed to work properly.
Therefore, if the capacitance of the electrolytic capacitor C1 recovers to “80%” obtained by adding a margin to the capacitance value “64%”, the low-temperature LED lighting device 100 operates sufficiently stably.

As described above, the initial time T1 may be set based on an actual measurement value or an experimental value (see FIG. 6), or may be obtained based on the calorific value of the electrolytic capacitor C1 and the temperature characteristics of the electrolytic solution.
That is, the target temperature of the electrolytic solution when the capacitance is “80%” at normal temperature is obtained based on the temperature characteristics of the electrolytic solution.
Next, based on the filling amount of the electrolytic solution, a heat quantity Q required to raise the electrolytic solution from a low temperature (for example, −60 degrees) to a target temperature is obtained.
Then, the time t required to generate the heat quantity Q is obtained as the initial time T1. The amount of heat Q and time t satisfy the relationship of “Q = I ² Rt”. I indicates the amount of current flowing through the electrolytic capacitor C1, and R indicates the internal impedance of the electrolytic capacitor C1.

  In this embodiment, the case where a light emitting diode is used as the light source has been described. However, any light source that can be lit even in a low temperature environment may be used, and the light source is not limited to the light emitting diode. For example, a light source having good lighting characteristics in a low temperature environment may be used, and a lighting characteristic improving function in a low temperature environment (for example, a function of heating the light source to a temperature having good lighting characteristics) may be provided in the lighting device. Moreover, what is necessary is just to comprise a lighting circuit part according to the kind of light source, and a lighting circuit part outputs an output current (a direct current or an alternating current).

Embodiment 2. FIG.
The output current control of the lighting circuit unit 140 that is different from the first embodiment will be described.
The circuit configuration of the low temperature LED lighting device 100 is the same as that of the first embodiment (see FIG. 1).

FIG. 7 is a graph showing output current control of the lighting circuit unit 140 in the second embodiment.
The output control of the lighting circuit unit 140 by the lighting control circuit unit 170 will be described with reference to FIG.

The lighting control circuit unit 170 gradually increases the amount of current output from the lighting circuit unit 140 to the light emitting diode unit 160.
For example, the lighting control circuit unit 170 outputs the output current of the lighting circuit unit 140 when the first current amount change time Ta elapses, when the second current amount change time Tb elapses, and when the third current amount change time T1 ( The initial current amount is increased from the initial current amount to the target current amount in three stages.

  Each current amount change time is stored and set in the timer circuit unit 180 in advance. The timer circuit unit 180 detects the lapse of each current amount change time based on the set value, and notifies the lighting control circuit unit 170 of the lapse of each current amount change time. The output current amount of the lighting circuit unit 140 when each current amount change time has elapsed is stored and set in the lighting control circuit unit 170 in advance. The lighting control circuit unit 170 increases the output current of the lighting circuit unit 140 to the set amount of the time each time a time elapse notification is received from the timer circuit unit 180. However, the output current amount of the lighting circuit unit 140 when each current amount change time elapses is such that the smoothing voltage of the electrolytic capacitor C1 is not lower than the forward voltage drop Vf of the light emitting diode unit 160.

By gradually increasing the output current of the lighting circuit section 140 until the initial time elapses, the electrolytic solution of the electrolytic capacitor C1 is thawed in a shorter time, and the capacitance of the electrolytic capacitor C1 is recovered in a shorter time. be able to. That is, an initial time shorter than that in Embodiment 1 can be set, and the light-emitting diode unit 160 can be lit at the target brightness earlier.
In addition, the brightness of the light emitting diode unit 160 can be changed in a stepwise manner, and the uncomfortable feeling with respect to the change in the brightness of the light emitting diode unit 160 can be reduced.

  However, the output current of the lighting circuit unit 140 may be increased stepwise from the initial current amount after the initial time T1 has elapsed and the capacitance of the electrolytic capacitor C1 has sufficiently recovered.

Embodiment 3 FIG.
The output current control of the lighting circuit unit 140 different from the first and second embodiments will be described.
The circuit configuration of the low temperature LED lighting device 100 is the same as that of the first embodiment (see FIG. 1).

FIG. 8 is a graph showing output current control of the lighting circuit unit 140 in the third embodiment.
The output control of the lighting circuit unit 140 by the lighting control circuit unit 170 will be described with reference to FIG.

The lighting control circuit unit 170 continuously outputs a current amount to be output from the lighting circuit unit 140 to the light emitting diode unit 160 at a predetermined increase rate or by a predetermined increase amount from the start time (T0) to the elapse of the initial time (T1). Increase. The increase rate or increase amount is stored and set in advance in the lighting control circuit unit 170. The timer circuit unit 180 detects the passage of the initial time.
As a result, the output current of the lighting circuit section 140 continuously increases from the initial current amount to the target current amount during the period from the start (T0) until the initial time T1 elapses.
However, it is assumed that the output current amount of the lighting circuit unit 140 at each time does not make the smoothing voltage of the electrolytic capacitor C1 lower than the forward drop voltage Vf of the light emitting diode unit 160.

By continuously increasing the output current amount of the lighting circuit unit 140, the electrolytic solution of the electrolytic capacitor C1 can be thawed in a shorter time, and the capacitance of the electrolytic capacitor C1 can be recovered in a shorter time. That is, an initial time shorter than that in Embodiment 1 can be set, and the light-emitting diode unit 160 can be lit at the target brightness earlier.
In addition, the feeling of strangeness with respect to the change in brightness of the light emitting diode unit 160 can be reduced by a fade-in effect.

  In the third embodiment, the lighting control circuit unit 170 does not increase the output current amount of the lighting circuit unit 140 until the initial time elapses, but lights up until the output current amount of the lighting circuit unit 140 reaches the target current amount. The amount of output current of the circuit unit 140 may be increased. In this case, the timer circuit unit 180 is not necessary.

Embodiment 4 FIG.
The output current control of the lighting circuit unit 140 different from the first to third embodiments will be described.

FIG. 9 is a circuit block diagram of LED lighting device 100 for low temperature in the fourth embodiment.
In FIG. 9, the low temperature LED lighting device 100 includes a ripple voltage detection circuit 190 instead of the timer circuit unit 180 (see FIG. 1). Other configurations are the same as those of the first to third embodiments.

  The ripple voltage detection circuit 190 is connected to a current input unit of the light emitting diode unit 160 and detects an applied voltage (an output voltage of the lighting circuit unit 140) applied to the light emitting diode unit 160.

  The lighting control circuit unit 170 changes the output current of the lighting circuit unit 140 from the initial current amount to the target current amount so that the applied voltage detected by the ripple voltage detection circuit 190 does not become lower than the forward drop voltage Vf of the light emitting diode unit 160. Increase to.

For example, a control table indicating control information (for example, a ratio of on-time of the switch element) of the lighting circuit unit 140 in association with the applied voltage of the light emitting diode unit 160 is stored and set in the lighting control circuit unit 170 in advance.
The lighting control circuit unit 170 controls the output current of the lighting circuit unit 140 based on this control table.

  For example, the lighting control circuit unit 170 increases the output current of the lighting circuit unit 140 continuously as shown in FIG. 8 or stepwise as shown in FIG.

By adjusting the output current of the lighting circuit unit 140 based on the voltage applied to the light emitting diode unit 160, the light emitting diode unit 160 can be lit with appropriate brightness.
In addition, the electrolytic solution of the electrolytic capacitor C1 can be thawed in a shorter time, and the capacitance of the electrolytic capacitor C1 can be recovered in a shorter time.

  DESCRIPTION OF SYMBOLS 100 Low temperature LED lighting device, 110 Input filter circuit part, 120 Rectifier circuit part, 130 Power supply smoothing part, 140 Lighting circuit part, 150 Output smoothing part, 160 Light emitting diode part, 170 Lighting control circuit part, 180 Timer circuit part, 190 Ripple voltage detection circuit.

Claims (8)

In the lighting device that lights the light source,
A rectifier circuit that inputs an alternating current, rectifies the input alternating current, and outputs a pulsating current;
An electrolytic capacitor that changes capacitance according to temperature and smoothes a pulsating current output from the rectifier circuit unit into a direct current;
A lighting circuit unit that inputs a direct current obtained by the electrolytic capacitor and outputs an output current of a predetermined target current amount to a light source, and the temperature of the electrolytic capacitor after the alternating current is input to the rectifier circuit unit The output current smaller than the target current amount is output to the light source until a predetermined initial time for the capacitance of the electrolytic capacitor to reach a predetermined amount elapses, and the target current amount is passed after the initial time has elapsed. A lighting circuit comprising: a lighting circuit unit that outputs the output current of the output to the light source. In the lighting device that lights the light source,
A rectifier circuit that inputs an alternating current, rectifies the input alternating current, and outputs a pulsating current;
A lighting circuit unit that inputs a pulsating current output from the rectifier circuit unit and outputs an output current of a predetermined target current amount to a light source;
An electrostatic capacitance that varies according to temperature, and an electrolytic capacitor that smoothes the output current output from the lighting circuit unit to the light source,
The lighting circuit unit is configured to increase the temperature of the electrolytic capacitor after an alternating current is input to the rectifier circuit unit until the predetermined initial time for the capacitance of the electrolytic capacitor to reach a predetermined amount elapses. A lighting device that outputs an output current smaller than a target current amount to a light source, and outputs an output current of the target current amount to the light source after the initial time has elapsed. The lighting device further includes:
A timer circuit unit for detecting the passage of the initial time;
The lighting circuit unit outputs an output current having a predetermined initial current amount smaller than the target current amount to the light source until the timer circuit unit detects the passage of the initial time, and the timer circuit unit passes the initial time. 3. The lighting device according to claim 1, wherein an output current of the target current amount is output to the light source after detecting the current. The lighting device further includes:
A timer circuit unit that detects the lapse of a plurality of current amount change times including the initial time,
The lighting circuit unit increases the output amount of the output current every time the timer circuit unit detects the elapse of the current amount change time, thereby reducing the magnitude of the output current output to the light source by a predetermined amount smaller than the target current amount. The lighting device according to claim 1, wherein the lighting device gradually increases from an initial current amount to the target current amount. The lighting device further includes:
A timer circuit unit for detecting the passage of the initial time;
The lighting circuit unit continuously increases the output amount of the output current until the timer circuit unit detects the passage of the initial time, thereby reducing the magnitude of the output current output to the light source to a predetermined initial amount smaller than the target current amount. The lighting device according to claim 1, wherein the lighting device continuously increases from a current amount to the target current amount. The lighting device is a lighting device that lights a plurality of light emitting diodes connected in series as a light source,
The initial current amount is based on the capacitance of the electrolytic capacitor corresponding to the temperature of the environment in which the lighting device is used, and the lower limit voltage of the DC voltage applied to the light source is a forward drop voltage of a plurality of light emitting diodes. The lighting device according to any one of claims 3 to 5, wherein the lighting device is determined as a current amount that is not lower. A lighting device that lights a plurality of light emitting diodes connected in series as a light source,
A rectifier circuit that inputs an alternating current, rectifies the input alternating current, and outputs a pulsating current;
A lighting circuit unit that inputs a pulsating current output from the rectifier circuit unit and outputs an output current of a predetermined target current amount to a light source;
A ripple voltage detection circuit that detects a ripple of the output voltage applied to the light source,
The lighting circuit unit sets the output current output to the light source from the target current amount so that the ripple of the output voltage detected by the ripple voltage detection circuit does not become lower than the forward drop voltage of the plurality of light emitting diodes. A lighting device that increases from a small predetermined initial current amount to the target current amount. The lighting device according to any one of claims 1 to 7,
An illumination device comprising: a light source having a light source including a plurality of light emitting diodes connected in series.