JP2010177012A - Lighting device, and illumination fixture having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of controlling power consumption of a lamp LA on the basis of ripple voltage and extending life of an electrolytic capacitor C1. <P>SOLUTION: The lighting device includes a power source rectifying circuit 20 for rectifying input AC voltage, a DC power source circuit 30 connected to the power source rectifying circuit 20 and having the electrolytic capacitor C1 which generates smooth voltage, a lighting circuit 40 connected to the electrolytic capacitor C1 and lighting up the lamp LA by converting to voltage corresponding to the lamp LA connected to the smooth voltage smoothed by the electrolytic capacitor C1, and a life detection circuit 50 connected to the electrolytic capacitor C1 in parallel and detecting ripple voltage of the electrolytic capacitor C1 and outputting a life level signal for reducing brightness of the lamp LA to the lighting circuit 40 when the detected ripple voltage is lower than a preset reference voltage L. Power consumption of the lamp LA can be controlled on the basis of the ripple voltage, and the life of the electrolytic capacitor C1 can be extended. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lighting device for lighting a lamp.

  There is a technique for determining the lifetime of a lighting device based on a ripple component included in the voltage across the capacitor in the lighting device and the current flowing in the capacitor at the end of the lifetime of the lighting device. (For example, Patent Document 1)

  In addition, when it is determined that the capacitor capacity of the electrolytic capacitor has decreased, there is a technique in which the switching element is forcibly turned on to flow an overcurrent, the overcurrent protection element is blown, and the power supply and the discharge lamp lighting circuit are disconnected. (For example, Patent Document 2)

  In addition, when the life of a capacitor is detected, there is a technology to increase the switching frequency, reduce the capacitor ripple current, suppress the internal heat generation of the capacitor, and extend the time until the capacitor bursts or breaks. There is a technology for correcting the fluctuation of the ripple voltage of the capacitor according to the use condition and eliminating the influence based on the temperature of the capacitor and the output current of the capacitor. (For example, Patent Document 3)

Japanese Patent Laying-Open No. 2006-236666 (see paragraphs “0020” to “0022” in FIG. 4) Japanese Patent Laying-Open No. 2007-207708 (see paragraph “0013”, FIG. 1) JP 2000-350448 A (refer to paragraph “0013”, paragraph “0024”, FIG. 1).

  However, if the overcurrent protection element is blown when the capacitor capacity of the electrolytic capacitor is reduced, the power source and the discharge lamp lighting circuit are disconnected, so that the lamp may suddenly disappear while the lamp is lit.

  Further, since the ripple voltage of the electrolytic capacitor increases or the tangent tan δ of the internal loss angle changes, the ripple heat generation of the electrolytic capacitor (self-heating due to the ripple current) increases, so the temperature of the electrolytic capacitor increases. There was a risk of aging deterioration of the electrolytic capacitor. Also, the internal pressure of the electrolytic capacitor may rise, and the electrolytic capacitor's safety valve may operate to release mist-like electrolyte. The user mistakes the mist-like electrolyte as smoke and mistakes it as a fire. There was a fear.

  In addition, the life of the lighting device is greatly affected by the life of the electrolytic capacitor. When the electrolytic capacitor reaches the end of its life, the fluctuation of the ripple voltage increases, and the operation of the lighting device may become unstable.

  A lighting device according to the present invention is connected to a power source rectifier circuit that rectifies an input AC voltage, a DC power source circuit having an electrolytic capacitor that is connected to the power source rectifier circuit and generates a smoothed voltage, and the electrolytic capacitor. The smoothing voltage is converted into a voltage corresponding to the connected lamp, and the lighting circuit for lighting the lamp, and connected in parallel to the electrolytic capacitor, detects the ripple voltage of the electrolytic capacitor, and the detected ripple voltage When the voltage is lower than a preset reference voltage, a life detection circuit is provided that outputs a life level signal for reducing the brightness of the lamp to the lighting circuit.

  According to the present invention, the power consumed by the lamp can be controlled based on the ripple voltage, and the life of the electrolytic capacitor can be extended.

3 is a circuit block diagram of a lighting device showing Embodiment 1. FIG. FIG. 6 is a waveform diagram showing the operation of each part of the lighting device showing the first embodiment. FIG. 6 is a waveform diagram showing the operation of each part of the lighting device showing the first embodiment. FIG. 6 is a characteristic diagram showing characteristics of the electrolytic capacitor showing the first embodiment. It is the lighting fixture shown in Example 1. FIG. 1 is a block diagram of a lighting device showing Example 1. FIG. FIG. 6 is a waveform diagram showing the operation of each part of the lighting device showing the first embodiment. FIG. 6 is a waveform diagram showing the operation of each part of the lighting device showing the first embodiment. FIG. 6 is a circuit block diagram of a lighting device showing a second embodiment. FIG. 6 is a circuit block diagram of another lighting device showing a second embodiment. 6 is a circuit block diagram of a lighting device showing Example 3. FIG. 6 is a circuit block diagram of a lighting device showing a second embodiment. FIG.

Embodiment 1 FIG.
FIG. 1 is a circuit block diagram showing the lighting device of the present embodiment.

  The lighting device 10 includes a power supply rectifier circuit 20 that converts an input AC voltage AC into a DC voltage using a diode bridge DB, a DC power supply circuit 30 that is connected to the power supply rectifier circuit 20 and smoothes the converted DC voltage, The smoothing voltage smoothed by the DC power supply circuit 30 is converted, and the lighting circuit 40 for lighting the connected lamp LA is connected. The DC power supply circuit 30 and the lighting circuit 40 are connected, and according to the ripple voltage of the DC power supply circuit 30. And a life detection circuit 50 for outputting a life level signal for changing the lighting state of the lamp LA to the lighting circuit 40.

  The DC power supply circuit 30 includes an electrolytic capacitor C1 that smoothes the DC voltage rectified by the power supply rectifier circuit 20 and generates a smoothed voltage.

  The lighting circuit 40 is a circuit that converts the smoothed voltage charged in the electrolytic capacitor C1 of the DC power supply circuit 30 into electric power corresponding to the type of the lamp LA to be connected and outputs the electric power. For example, the lamp LA connected to the lighting device 10 is a discharge lamp, LED, halogen lamp, or the like. For example, when the lamp LA connected to the lighting device 10 is a discharge lamp, an inverter circuit that outputs a high-frequency current. Is used as the lighting circuit 40, and a constant current circuit that outputs a constant current is used as the lighting circuit 40 when the lamp LA connected to the lighting device 10 is an LED.

  The life detection circuit 50 is connected in parallel to the DC power supply circuit 30, and a ripple voltage detection circuit 51 that detects a ripple voltage from the smoothed voltage of the DC power supply circuit 30 and a ripple voltage that the ripple voltage detection circuit 51 detects are preset. And a detection signal determination circuit 52 that outputs a life level signal when the reference voltage L falls below.

  The ripple voltage detection circuit 51 is connected in parallel to the electrolytic capacitor C1, and outputs a ripple voltage detection signal corresponding to the smoothed voltage smoothed by the electrolytic capacitor C1. The ripple voltage detection circuit 51 is a circuit that detects the level of the ripple voltage superimposed on the DC voltage smoothed by the electrolytic capacitor C1, and outputs the ripple voltage detection signal to the detection signal determination circuit 52 according to the level of the ripple voltage. It is a circuit to send out.

  The detection signal determination circuit 52 compares the input ripple voltage detection signal with a preset reference voltage L, and when the ripple voltage detection signal is lower than the reference voltage L, it responds to a ratio lower than the reference voltage L. Outputs a life level signal. For example, if the ripple voltage detection signal is equal to or higher than a preset reference voltage L, the detection signal determination circuit 52 does not output a life level signal to the lighting circuit 40 and the reference voltage L for which the ripple voltage detection signal is preset. If it is less, a life level signal corresponding to a level below the reference voltage L is output to the lighting circuit 40.

  Next, operation | movement of the lighting device 10 when a ripple voltage changes with the change of the capacitor | condenser capacity | capacitance of the electrolytic capacitor C1 is demonstrated.

  FIG. 2 is a characteristic diagram showing the characteristics of each part when the electrolytic capacitor is in the initial state (new product), FIG. 2 (a) is a diagram showing the voltage of the electrolytic capacitor, and FIG. It is a figure which shows the voltage which a ripple voltage detection circuit detects, and FIG.2 (c) is a figure which shows the brightness of a lamp | ramp.

  Since the ripple voltage is small when the electrolytic capacitor C1 is in the initial state, the fluctuation of the output of the ripple voltage detection circuit 51 is also small. Therefore, the ripple voltage detection signal output from the ripple voltage detection circuit 51 is higher than the reference voltage L of the detection signal determination circuit 52.

  Therefore, since the ripple voltage detection signal is higher than the reference voltage L, the detection signal determination circuit 52 does not output a life level signal, and the lighting circuit 40 normally lights the lamp LA.

  FIG. 3 is a characteristic diagram showing the characteristics of each part in the state before the electrolytic capacitor is aged and reaches the end of its life, and FIG. 3A is a diagram showing the voltage of the electrolytic capacitor, and FIG. ) Is a diagram showing the voltage detected by the ripple voltage detection circuit, and FIG. 3C is a diagram showing the brightness of the lamp.

  Since the capacitor capacity gradually decreases until the electrolytic capacitor C1 deteriorates over time and reaches the end of its life (when it is reduced to 50% of the initial capacitor capacity), the ripple voltage of the electrolytic capacitor C1 gradually increases. . At this time, the level of the ripple voltage detection signal output from the ripple voltage detection circuit 51 gradually increases.

  When the level of the ripple voltage detection signal gradually increases and the lower limit value of the ripple voltage detection signal output from the ripple voltage detection circuit 51 is lower than the reference voltage L of the detection signal determination circuit 52, the detection signal determination circuit 52 Output level signal. This life level signal is a difference signal corresponding to a voltage value lower than the reference voltage L. For example, when the ripple voltage detection signal is 1V below the reference voltage L, a life level signal of 0.5V is output, and when the ripple voltage detection signal is 5V below the reference voltage L, a life level signal of 2.5V is output.

  When the life level signal is input, the lighting circuit 40 controls the lamp LA to decrease in brightness and to reduce the power consumed by the lamp LA according to the level of the life level signal.

  When the power consumed by the lamp LA is reduced, the load on the electrolytic capacitor C1 (in this case, the power consumed by the lighting circuit 40 and the lamp LA) is reduced, and the ripple voltage of the electrolytic capacitor C1 is reduced.

  For convenience of explanation of the life level signal, “when the ripple voltage detection signal is 1 V or 2.5 V below the reference voltage L” is used. However, when the ripple voltage detection signal reaches the reference voltage L, the lamp LA The ripple voltage of the electrolytic capacitor C1 is reduced by controlling so that the power consumed by the lamp LA is reduced and the ripple voltage detection signal is not significantly lower than the reference voltage L. Therefore, the life detection circuit 50 outputs a life level signal to the lighting circuit 40 so that the ripple voltage detection signal is substantially equal to the reference voltage L.

  Next, the difference in aging degradation (decrease in capacitor capacity) of the electrolytic capacitor C1 depending on the presence or absence of the life detection circuit 50 will be described.

  FIG. 4 is a diagram showing the relationship between the aging time depending on the presence / absence of the life detection circuit and the capacitance of the electrolytic capacitor.

  The capacitor capacity of the electrolytic capacitor C1 decreases with the passage of time, assuming that the capacitor capacity when new is 100%. This is because the electrolytic solution inside the electrolytic capacitor C1 evaporates with time, and the capacitance of the electrolytic capacitor C1 gradually decreases.

  In this embodiment, when the capacitor capacity of the electrolytic capacitor C1 elapses to 50%, the lifetime of the electrolytic capacitor C1 is set.

  Here, the lifetime of the electrolytic capacitor C1 will be described. When the lifetime of a part such as the electrolytic capacitor C1 is τ, the inherent constants for each failure mode are A and Ea, the absolute temperature is T, and the Boltzmann constant is k, the relationship τ = A · exp (Ea / kT) is established. There is Arrhenius' law that holds. It is known that the life of a general electrolytic capacitor is doubled when the operating temperature is lowered by 10 ° C. according to the Arrhenius law. In other words, if the operating temperature rises by 10 ° C, it can be said that the life is halved.

  Therefore, when the electrolytic capacitor C1 deteriorates over time, the internal electrolytic solution of the electrolytic capacitor C1 decreases, so that the capacitor capacity decreases and the ripple voltage increases. In this state, since ripple heat generation also increases, the decrease of the internal electrolyte proceeds at an accelerated rate.

  Further, when the electrolytic capacitor C1 deteriorates over time, the current loss flowing through the electrolytic capacitor C1 increases and the self-heating of the electrolytic capacitor C1 increases. Therefore, the temperature rises due to self-heating of the electrolytic capacitor C1, leading to a shortened life of the electrolytic capacitor C1.

  Thus, it can be seen that the lifetime of the electrolytic capacitor C1 varies depending on the environment in which the electrolytic capacitor C1 is used.

  Next, the operation of the lighting device 10 when detecting aged deterioration of the electrolytic capacitor C1 will be described.

  In the lighting device 10 shown in this embodiment, since the pulsating flow rectified by the power supply rectifier circuit 20 is smoothed by the electrolytic capacitor C1, the peak voltage value of the electrolytic capacitor C1 is regulated to the peak voltage value of the pulsating voltage. On the other hand, the lower limit of the ripple voltage of the smoothing voltage of the electrolytic capacitor C1 is regulated by the capacitor capacity and the power consumed by the lamp LA and the lighting circuit 40, and the capacitor capacity decreases or is consumed by the lamp LA and the lighting circuit 40. As the power increases, the lower limit of the ripple voltage of the electrolytic capacitor C1 decreases, and thus the ripple voltage increases.

  When the electrolytic capacitor C1 is new, the smoothed voltage smoothed by the DC power supply circuit 30 has a peak voltage output from the power supply rectifier circuit 20 (maximum value of the ripple voltage), and the capacitor capacity of the electrolytic capacitor C1 and the lamp LA. The lower limit value of the ripple voltage is determined according to the power consumed by.

  Therefore, the ripple voltage generated when the electrolytic capacitor C1 is smoothed increases in accordance with the ratio of the capacitor capacity of the electrolytic capacitor C1 that has deteriorated over time to the capacitor capacity of the electrolytic capacitor C1 when new.

  Therefore, the life detection circuit 50 detects the level of the ripple voltage of the electrolytic capacitor C1 accompanying the aging deterioration of the electrolytic capacitor C1, changes the lighting state of the lamp LA, and reduces the power consumed by the lamp LA. The ripple voltage of the electrolytic capacitor C1 falls within a predetermined range, and self-heating of the electrolytic capacitor C1 can be suppressed.

  Therefore, as shown in FIG. 4, the life characteristics of the electrolytic capacitor C <b> 1 change depending on the presence / absence of the life detection circuit 50, and the life of the electrolytic capacitor C <b> 1 is extended by the life detection circuit 50.

  Further, as the ripple voltage increases, the electrolytic capacitor C1 has a larger current loss (tan δ) flowing through the electrolytic capacitor C1, and the electrolytic capacitor C1 self-heats due to this current loss.

  However, since the ripple voltage is affected by the capacitor capacity of the electrolytic capacitor C1 and the power supplied to the lamp LA, when the ripple voltage is lower than the reference voltage L, the ripple voltage is reduced by reducing the power supplied to the lamp LA. Can be suppressed.

  Accordingly, since the current loss of the electrolytic capacitor C1 can be reduced, the self-heating (ripple heat generation) of the electrolytic capacitor C1 can be reduced.

  Therefore, since the temperature rise of the electrolytic capacitor C1 can be suppressed, the life characteristic curve can be moderated, and the life of the electrolytic capacitor C1 can be extended.

  Further, since the brightness of the lamp LA is changed depending on the magnitude of the ripple voltage, it is possible to inform the user that the life of the lighting device 10, particularly the life of the electrolytic capacitor C <b> 1 is approaching.

  In this embodiment, the reference voltage L is set based on the negative side of the ripple voltage (the low side of the ripple voltage), but the positive side of the ripple voltage of the DC power supply circuit 30 (the high side of the ripple voltage). May change, the reference voltage L may be set to the positive side, or the reference voltage L may be set to both the positive side and the negative side.

  Further, when the capacitor capacity of the electrolytic capacitor C1 is large, the ripple voltage becomes small. Therefore, since the ripple voltage detection signal detected by the detection signal determination circuit 52 is higher than the reference voltage L, the reference voltage L may be appropriately set according to the capacitor capacity of the electrolytic capacitor C1 to be used.

  In addition, since the power consumed by the lamp LA is very large as compared with the power consumed by the lighting circuit 40 or the like, the lighting device 10 of the present embodiment has a lamp LA when the ripple voltage falls below the reference voltage L. However, when the power consumed by the lamp LA is small, the operation of the circuit with large power consumption is temporarily limited or stopped within a range in which the lighting device 10 operates normally. You may control as follows.

  In the present embodiment, the lifetime is defined as when the capacitor capacity of the electrolytic capacitor C1 is reduced to 50% of the initial capacitor capacity. However, depending on the electrical characteristics depending on the type of the electrolytic capacitor C1 used in the lighting device 10. The lifetime of the electrolytic capacitor C1 is not limited to when the capacitor capacity is reduced to 50% with respect to the initial capacitor capacity.

  Note that the capacitor capacity of the electrolytic capacitor C1 decreases as the electrolytic solution evaporates over time even when the lighting device 10 is not energized. Further, the decrease in the capacitance of the electrolytic capacitor C1 is greatly affected by the environment in which the electrolytic capacitor C1 is used. Accordingly, the influence of the electronic parts (including the self-heating of the electrolytic capacitor C1) that generates heat when the lighting device 10 is energized has a large effect on the life of the electrolytic capacitor C1 (the life of the electrolytic capacitor C1 is shortened). Therefore, in the present embodiment, the life characteristics of the electrolytic capacitor C1 when the lighting device 10 is energized have been described. When the lighting device 10 is not energized, the slope of the life characteristic of the electrolytic capacitor C1 shown in FIG.

Example 1.
This example shows a specific configuration of the life detection circuit and the lighting circuit described in this embodiment.

FIG. 5 is a lighting fixture showing the present embodiment.
The luminaire 100 includes a fixture body 101 that houses a lighting device 10a that supplies power to the discharge lamp LA1, and a lamp socket that mechanically holds the discharge lamp LA1 and electrically connects the discharge lamp LA1 and the lighting device 10a. 102.

Next, the lighting device of the present embodiment will be described with reference to FIG.
FIG. 6 is a circuit block diagram showing a specific configuration of the life detection circuit and the lighting circuit of the lighting device according to the present embodiment.

  The lighting device 10a includes a power supply rectifier circuit 20 that converts an input AC voltage AC into a DC voltage using a diode bridge DB, a DC power supply circuit 30 that is connected to the power supply rectifier circuit 20 and smoothes the converted DC voltage, The smoothing voltage smoothed by the DC power supply circuit 30 is converted, and the lighting circuit 40a for lighting the connected discharge lamp LA1 is connected to the DC power supply circuit 30 and the lighting circuit 40a. Accordingly, a life detection circuit 50a for outputting a life level signal for changing the lighting state of the discharge lamp LA1 to the lighting circuit 40a is provided.

  The lighting circuit 40a is connected to the inverter circuit 41 that converts the smoothed voltage smoothed by the DC power supply circuit 30 into a high-frequency voltage, the control circuit 42 that controls the switching of the inverter circuit 41, and the discharge lamp LA1. A load circuit 43 that supplies a high-frequency voltage converted by the inverter circuit 41 to the discharge lamp LA1 is provided.

  The load circuit 43 has one end connected to the inverter circuit 41, the other end connected to the discharge lamp LA1, an inductor L1, a capacitor C2 connected in parallel with the connected discharge lamp LA1, and one end connected to the discharge lamp LA1. And a coupling capacitor C3 having the other end connected to the inverter circuit 41. The resonance of the inductor L1 and the capacitor C2 is used to light the connected discharge lamp LA1, and the coupling capacitor C3 The direct current flowing in the load circuit 43 is limited.

  The inverter circuit 41 has an FET Q1 whose drain terminal is connected to the positive potential side of the DC power supply circuit, an FET whose drain terminal is connected to the source terminal of the FET Q1, and whose source terminal is connected to the negative potential side of the DC power supply circuit. Q2 is a circuit that alternately switches FETs Q1 and Q2 to convert the smoothed voltage smoothed by the DC power supply circuit 30 into a high-frequency voltage.

  The control circuit 42 determines an operating frequency at which the inverter circuit 41 performs a switching operation, and inputs a life level signal output from the life detecting circuit 50a, a frequency setting circuit 42a that changes the operating frequency of the inverter circuit 41; And an inverter control circuit 42b for turning on / off the FETs Q1 and Q2 of the inverter circuit 41 at an operating frequency set by the frequency setting circuit 42a.

  The frequency setting circuit 42a is a circuit that determines the oscillation frequency of the inverter circuit 41. The frequency setting circuit 42a receives the signal transmitted from the life detection circuit 50a and changes the frequency based on the result. Since the load circuit 43 is composed of an LC resonance circuit including the inductor L1 and the capacitor C2, the load output (power supplied to the discharge lamp LA1) decreases as the frequency increases.

  When the life level signal is input, the frequency setting circuit 42a changes the oscillation frequency of the inverter circuit 41 according to the input life level signal.

  The inverter control circuit 42b is a circuit for alternately turning on / off the FETs Q1 and Q2 at a frequency designated by the frequency setting circuit 42a.

  The life detection circuit 50a includes a ripple voltage detection circuit 51a connected in parallel to the electrolytic capacitor C1, and a detection signal determination circuit 52a connected to the ripple voltage detection circuit 51a and connected to the lighting circuit 40a.

  The ripple voltage detection circuit 51a includes resistors R1 and R2 connected in series. The series connected R1 and R2 are connected in parallel to the electrolytic capacitor C1, and the electrolytic capacitor C1 is smoothed from the connection point of the resistors R1 and R2. A ripple voltage detection signal corresponding to the smooth voltage is output. The ripple voltage detection circuit 51a is a circuit that detects the level of the ripple voltage superimposed on the DC voltage smoothed by the electrolytic capacitor C1, and outputs the ripple voltage detection signal to the detection signal determination circuit 52a according to the level of the ripple voltage. It is a circuit to send out.

  The detection signal determination circuit 52a includes a reference voltage setting circuit 53a that divides the control power supply voltage Vcc by resistors R3 and R4 connected in series to generate a reference voltage L, and a reference voltage L that is set by the reference voltage setting circuit 53a. An operational amplifier OP that compares the ripple voltage detection signal output from the ripple voltage detection circuit 51a, a detection signal generation circuit 54a that is connected to the output terminal of the operational amplifier OP and generates a life level signal based on the output of the operational amplifier OP; Is provided.

  The detection signal generation circuit 54a includes a resistor R5 having one end connected to the output terminal of the operational amplifier OP, a diode D1 having a cathode terminal connected to the other end of the resistor R5, and an anode terminal connected to the frequency setting circuit 42a, Is provided.

  Next, the circuit operation of the lighting device of the present embodiment will be described.

  FIG. 7 is a characteristic diagram showing the characteristics of each part when the electrolytic capacitor is in the initial state (when new), FIG. 7A is a diagram showing the voltage of the electrolytic capacitor, and FIG. FIG. 7C is a diagram showing the voltage detected by the ripple voltage detection circuit, FIG. 7C is a diagram showing the oscillation frequency of the inverter circuit, and FIG. 7D is a diagram showing the brightness of the discharge lamp.

  When the electrolytic capacitor C1 is in the initial state (when it is new), the fluctuation of the ripple voltage is small, and the ripple voltage detected by the ripple voltage detection circuit 51 is higher than the reference level. Therefore, since the ripple voltage detection circuit 51 does not output a life level signal, the oscillation frequency of the inverter circuit 41 is constant, and the brightness of the discharge lamp LA1 is also constant.

  FIG. 8 is a characteristic diagram showing the characteristics of each part in a state before the electrolytic capacitor is aged and reaches the end of its life, and FIG. 8A is a diagram showing the voltage of the electrolytic capacitor, and FIG. ) Is a diagram showing the voltage detected by the ripple voltage detection circuit, FIG. 8 (c) is a diagram showing the oscillation frequency of the inverter circuit, and FIG. 8 (d) is a diagram showing the brightness of the lamp. is there.

  As the electrolytic capacitor C1 deteriorates over time, the fluctuation of the ripple voltage increases, and the ripple voltage detected by the ripple voltage detection circuit 51a becomes lower than the reference voltage L. Therefore, the ripple voltage detection circuit 51a outputs a life level signal, and the inverter circuit 41 varies the oscillation frequency of the inverter circuit 41 according to the life level signal. Therefore, the brightness of the discharge lamp LA1 also varies according to the oscillation frequency of the inverter circuit 41.

  In this embodiment, the case where the AC voltage AC is 200V will be described. The AC voltage AC is not limited to 200V, and may be 100V or 254V.

  The smoothed voltage smoothed by the electrolytic capacitor C1 of the DC power supply circuit 30 is divided by the resistors R1 and R2 of the ripple voltage detection circuit 51a to output a ripple voltage detection signal.

  This ripple voltage detection signal is compared with the reference voltage L by the operational amplifier OP of the detection signal determination circuit 52a.

  For example, it is assumed that the ripple voltage range (initial value when the electrolytic capacitor is new) is 5 V when the electrolytic capacitor C1 is new and the discharge lamp LA1 is lit with 100% brightness.

  In this case, the smoothing voltage smoothed by the DC power supply circuit 30 has a maximum value of 282V and a lower limit value of 277V.

  On the other hand, the smoothing voltage smoothed by the DC power supply circuit 30 does not change to a maximum value of 282 V when the capacitor capacity of the electrolytic capacitor C1 decreases, but the lower limit value decreases according to the rate of decrease of the capacitor capacity (for example, 254V), the ripple voltage increases.

  When the ripple voltage detection signal is equal to or higher than the reference voltage L, the detection signal determination circuit 52a does not output a life level signal from the operational amplifier OP. In addition, when the ripple voltage detection signal is lower than the reference voltage L, the detection signal determination circuit 52a has a life level corresponding to a ratio lower than the reference voltage L from the operational amplifier OP (difference that is lower when the ripple voltage is lower than the reference level L). Send a signal.

  When the life level signal is not input, the frequency setting circuit 42a outputs a frequency signal to the inverter control circuit 42b so as to operate at a preset operating frequency. When the life level signal is input, the frequency setting circuit 42a A frequency signal higher than the preset operating frequency is output to the inverter control circuit 42b based on the signal. The operating frequency at this time is output to the inverter control circuit 42b as a frequency signal whose operating frequency increases as the ripple current detection signal compared by the operational amplifier OP becomes lower than the reference voltage L.

  The frequency setting circuit 42a in this embodiment determines the frequency for oscillating the inverter circuit 41 according to the amount of current drawn from the frequency setting circuit 42a, and the amount of current drawn from the frequency setting circuit 42a via the operational amplifier OP. Is adjusted.

  The frequency setting circuit 42a shifts the set frequency higher as the difference is larger. As a result, the load output is reduced (the power supplied to the discharge lamp LA1 is reduced), so that the ripple voltage is lowered. By repeating this operation, the ripple voltage is controlled to be equal to the set reference level, and self-heating (ripple heat generation) due to the ripple current when the capacity of the electrolytic capacitor C1 is reduced can be reduced. That is, since the shortening of the accelerated life when the capacitor capacity of the electrolytic capacitor C1 is reduced can be avoided, the life of the electrolytic capacitor C1 can be extended.

  The detection signal determination circuit 52a compares the input ripple voltage detection signal with a preset reference voltage L. When the ripple voltage detection signal is lower than the reference voltage L, the detection signal determination circuit 52a responds to a ratio lower than the reference voltage L. Outputs a life level signal. The detection signal determination circuit 52a outputs a life level signal for changing the lighting state of the discharge lamp LA1 based on the ripple voltage detection signal detected by the ripple voltage detection circuit 51a. For example, if the ripple voltage detection signal is equal to or higher than a preset reference voltage L, the life level signal is not output so that the frequency of the inverter circuit 41 becomes normal, and the ripple voltage detection signal is set in advance. If it is less, the frequency of the inverter circuit 41 is changed to a linear (higher frequency) according to the level below the reference voltage L, and the discharge lamp LA1 is dimmed.

  The detection signal determination circuit 52a of the present embodiment has been described with respect to the case where the operational amplifier OP is used. However, when the ripple voltage falls below the range of the reference voltage L, the transistor is actively operated to generate the life level signal. In addition, the life level signal may be generated using a microcomputer or the like.

  In this embodiment, a case has been described in which the DC power supply circuit 30 is a capacitor input system including an electrolytic capacitor C1 that smoothes the DC voltage rectified by the power supply rectifier circuit 20 and generates a smoothed voltage.

Example 2
This example shows a specific structure of the lighting device described in this embodiment. Further, the present embodiment is different in the configuration of the DC power supply circuit shown in the first embodiment.

  In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The lighting device of this embodiment will be described with reference to FIG.
FIG. 9 is a circuit block diagram showing the lighting device of the present embodiment.

  The lighting device 10b includes a power rectifier circuit 20 that converts an AC voltage AC into a DC voltage using a diode bridge DB, and an active filter that is connected to the power rectifier circuit 20 and boosts the voltage to a voltage higher than the voltage output from the power rectifier circuit 20. The circuit 30b includes a lighting circuit 40b that converts the voltage output from the active filter circuit 30b into power supplied to the discharge lamp LA1, and a life detection circuit 50a that determines a ripple voltage from the voltage output from the active filter circuit 30b.

  The active filter circuit 30b is connected in parallel to the inductor L2, the FET Q3, the step-up chopper control circuit 31a for controlling on / off of the FET Q3, the diode D2, the electrolytic capacitor C1a, and the electrolytic capacitor C1a. The resistors R6 and R7 connected in series for detecting the average voltage of the capacitor C1a are provided.

  The boosted voltage output from the active filter circuit 30b is such that the voltage detected by the resistors R6 and R7 (the average value of the smoothing voltage of the electrolytic capacitor C1a) is constant by the boost chopper control circuit 31a controlling the switching of the FET Q3. Is controlled.

  The life detection circuit 50a includes resistors R1 and R2 connected in series, and a ripple voltage detection circuit 51a that outputs a ripple voltage detection signal, and a detection that compares the ripple voltage detection signal output from the ripple voltage detection circuit 51a with the reference voltage L. And a signal determination circuit 52a.

  When the electrolytic capacitor C1a is in an initial (new) state, the voltage of the electrolytic capacitor C1a has a maximum value and a minimum value of about ± 5% of the average value. When the electric power consumed by the discharge lamp LA1 is constant while the electrolytic capacitor C1a is deteriorated, the voltage of the electrolytic capacitor C1a has a maximum value and a minimum value of about ± 10% of the average value. Further, the ripple current increases as the load increases.

  When the electric power consumed by the discharge lamp LA1 is changed according to the ripple voltage by the life detection circuit 54a when the electrolytic capacitor C1a is in a deteriorated state, the maximum and minimum values of the voltage of the electrolytic capacitor C1a are ±± It is controlled to be about 7-8%.

  In this embodiment, a circuit for detecting the average voltage of the electrolytic capacitor C1a (series connected resistors R6 and R7) and a ripple voltage detecting circuit 51a for detecting ripple voltage (series connected resistors R1 and R2) are electrolyzed. Although the case where the capacitor C1a is connected in parallel has been described, a plurality of series-connected resistors R1a, R2a, R7a are connected in parallel to the electrolytic capacitor C1a as in the life detection circuit 50b of the lighting device 10c shown in FIG. The circuit for detecting the average voltage of the capacitor C1a and the ripple voltage detection circuit for detecting the ripple voltage may be combined into one to form the electrolytic capacitor voltage detection circuit 51b.

  In this embodiment, the case of the active filter system having the active filter circuit 30b that boosts the DC voltage rectified by the power supply rectifier circuit 20 has been described.

Example 3 FIG.
This example shows a specific structure of the lighting device described in this embodiment. Further, the present embodiment is different in the configuration of the lighting circuit shown in the first embodiment.

  In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The lighting device of the present embodiment will be described with reference to FIG.
FIG. 11 is a circuit block diagram showing the lighting device of the present embodiment.

First, the configuration of the lighting device 10d will be described.
The lighting device 10d is connected to the power rectifier circuit 20 that converts the input AC voltage AC into a pulsating DC voltage, and is connected to the power rectifier circuit 20 so that the converted DC voltage of the pulsating current becomes a substantially constant voltage. A DC power supply circuit 30c having a primary electrolytic capacitor C1b to be smoothed, a lighting circuit 40c connected to the primary electrolytic capacitor C1b and supplying power to the connected LED lamp LA2, and a ripple voltage of the primary electrolytic capacitor C1b A life detection circuit 50c for detecting

  The lighting circuit 40c detects a load current flowing in the flyback circuit 41a connected to the primary electrolytic capacitor C1b, the secondary electrolytic capacitor C1c connected to the flyback circuit 41a, and the connected LED lamp LA2. A detection circuit 43 and a control circuit 42c for controlling the flyback circuit 41a are provided so that the current detected by the current detection circuit 43 is substantially constant.

  The flyback circuit 41a includes a transformer T1 whose one end on the primary side is connected to the high potential side of the primary electrolytic capacitor C1b, and a switching circuit 44 that is connected to the other end on the primary side of the transformer T1 and is turned ON / OFF. And a diode D3 having an anode terminal connected to one end on the secondary side of the transformer T1.

  The control circuit 42c includes a reference value setter DE that sets a reference value that determines the current flowing through the load, and a comparator CP that compares the current value detected by the current detection circuit 43 with the reference value of the reference value setter DE. And a switching circuit control signal generation unit PQ that generates a control signal for on / off control of the switching circuit 44 and outputs the generated control signal according to the result of comparison by the comparator CP.

  The switching circuit control signal generation unit PQ includes a phototransistor and electrically insulates the primary side and the secondary side of the lighting device 10d.

  The switching circuit 44 includes a switching unit SW made of an FET or the like, and an on / off controller CT that is connected to the switching circuit control unit 42c and switches on / off of the switching unit SW according to an input control signal.

  The life detection circuit 50c detects the ripple voltage of the primary side electrolytic capacitor C1b, and outputs a life level signal corresponding to the detected ripple voltage to the control circuit 42c.

  In addition, although the power supply rectifier circuit 20 of the present embodiment has been described with respect to the case where the input AC voltage AC is converted into a pulsating DC voltage, the input AC voltage AC is based on the peak voltage of the input AC voltage AC. A step-up chopper type circuit that steps up to a higher voltage may be used, or a step-down chopper type circuit that steps down the input AC power supply AC to a voltage lower than the peak voltage of the input AC power supply may be used. .

  Further, although the switching unit SW of the present embodiment has been described with respect to the case where the FET is used, it may be another semiconductor switching element such as a bipolar transistor or a mechanical switching element such as a relay.

  In this embodiment, the switching circuit control signal generation unit PQ is provided with a phototransistor to insulate the primary side and the secondary side of the lighting device 10d and to turn on the switching unit SW via the on / off controller CT. Although the case where the on / off control is performed has been described, the switching circuit control signal generation unit PQ may directly control the on / off of the switching unit SW without using the on / off controller CT.

  Next, the operation of the lighting device 10d will be described.

  The primary side of the transformer T1 is supplied with electric power smoothed by the primary side electrolytic capacitor C1b according to the ON / OFF operation of the switching circuit 44, and flows to the primary side of the transformer T1 to the secondary side of the transformer T1. A secondary current corresponding to the primary current flows, and a secondary voltage corresponding to the turns ratio of the transformer T1 is generated.

  The secondary voltage generated on the secondary side of the transformer T1 is rectified by the diode D3 and charged in the secondary side electrolytic capacitor C1c. The electric power charged in the secondary electrolytic capacitor C1c is supplied to the LED lamp LA2 to be connected.

  The control signal generated by the switching circuit control signal generation unit PQ is a signal having a substantially constant frequency (for example, a control signal having a frequency of 100 kHz), and the switching circuit 44 is turned on / off according to the result of comparison by the comparator CP. Change the duty. For example, when it is determined that the current value detected by the current detection circuit 43 by the comparator CP is large, a control signal that shortens the ON time of the switching circuit 44 is generated, and the current detected by the current detection circuit 43 by the comparator CP is generated. When it is determined that the value is small, a control signal that increases the ON time of the switching circuit 44 is generated.

  Next, the operation of the lighting device 10d when the life detection circuit 50c detects a ripple voltage will be described.

  When the primary electrolytic capacitor C1b deteriorates and the fluctuation range of the ripple voltage increases, the on / off duty of the switching circuit 44 is changed to suppress the power supplied to the LED lamp LA2.

  In the present embodiment, the case where the life detection circuit 50c is connected in parallel to the primary electrolytic capacitor C1b and the ripple voltage of the primary electrolytic capacitor C1b is detected has been described. The ripple voltage of the secondary electrolytic capacitor C1c may be detected by connecting in parallel with the capacitor C1c.

  Further, the life detection circuit 50c is connected in parallel to the primary side electrolytic capacitor C1b and the secondary side electrolytic capacitor C1c, respectively, and either one of the primary side electrolytic capacitor C1b or the secondary side electrolytic capacitor C1c has a ripple voltage. You may control so that the electric power which LED lamp LA2 consumes when it falls below the reference voltage L may be reduced.

  In addition, when the life characteristics of the primary side electrolytic capacitor C1b and the life characteristics of the secondary side electrolytic capacitor C1c are different, the circuit configuration constituting the lighting device 10d is simplified if the life detection circuit 50c is provided on the shorter life side. In addition, the lifetimes of the primary side electrolytic capacitor C1b and the secondary side electrolytic capacitor C1c can be extended. Thus, in the case of a lighting device including a plurality of electrolytic capacitors, it is desirable to provide a life detection circuit in parallel with the electrolytic capacitor having the shortest life.

Embodiment 2. FIG.
In the present embodiment, the configuration of the ripple voltage detection circuit of the lighting circuit shown in the first embodiment is different.

  In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 12 is a circuit block diagram illustrating a configuration of the lighting device according to the present embodiment.

  The lighting device 10e includes a power supply rectifier circuit 20 that converts an input AC voltage AC into a DC voltage by a diode bridge DB, a DC power supply circuit 30 that is connected to the power supply rectifier circuit 20 and smoothes the converted DC voltage, The smoothing voltage smoothed by the DC power supply circuit 20 is converted, and the lighting circuit 40 for lighting the connected lamp LA is connected to the DC power supply circuit 20 and the lighting circuit 40. A life detecting circuit 50d for outputting a life level signal for changing the lighting state of the lamp LA to the lighting circuit 40.

  The life detection circuit 50d receives a ripple voltage detection circuit 51 that detects a ripple voltage and a ripple voltage detection signal of the ripple voltage detection circuit 51, and whether or not the electrolytic capacitor C1 has a life from the input ripple voltage detection signal. And a detection signal determination circuit 52b that outputs a life level signal based on the determination result.

  The detection signal determination circuit 52b has a count unit 55 that compares the ripple voltage detected by the ripple voltage detection circuit 51 with the reference voltage L and counts the number of times that the reference voltage L falls below, and the number of times that the count unit 55 counts. When the current reaches a predetermined number of times (for example, 120 times), a life level signal corresponding to the level at which the ripple voltage falls below the reference voltage L is output to the lighting circuit 40.

  Generally, a commercial power supply (AC power supply) supplied by an electric power company is 50 Hz or 60 Hz, and the time during which an instantaneous power failure or power sag occurs is about 2 seconds or less. Therefore, assuming that the count unit 55 counts about 120 times, when the ripple voltage detection circuit 51 outputs a ripple voltage detection signal lower than the reference voltage L due to an instantaneous power failure or a power supply sag, the detection signal determination circuit 52b has a lifetime. The output of the level signal can be eliminated.

  In this way, since the number of times the ripple voltage detection signal falls below the reference voltage L is counted, the ripple voltage detection signal is obtained when the electrolytic capacitor C1 has not reached its original life, such as when the AC voltage AC changes transiently. Is less than the reference voltage L, the output of the lighting circuit 40 is not limited. Therefore, the user who uses the lighting apparatus does not feel uncomfortable or misunderstands that the lighting apparatus is out of order due to temporarily darkening.

  10, 10a, 10b, 10c, 10d, 10e lighting device, 20 power rectifier circuit, 30, 30a, 30c DC power supply circuit, 30b active filter circuit, 31a boost chopper control circuit, 40, 40a, 40b, 40c lighting circuit, 41 Inverter circuit, 41a Flyback circuit, 42, 42c Control circuit, 42a Frequency setting circuit, 42b Inverter control circuit, 43 Current detection circuit, 44 Switching circuit, 50, 50a, 50b, 50c, 50d Life detection circuit, 51, 51a Ripple Voltage detection circuit, 51b Electrolytic capacitor voltage detection circuit, 52, 52a, 52b Detection signal determination circuit, 53a Reference voltage setting circuit, 54a Detection signal generation circuit, 55 Count unit, 100 Lighting fixture, 101 Appliance body, 102 Lamp socket, ACCurrent voltage, DB diode bridge, C1, C1a, electrolytic capacitor, C1b primary side electrolytic capacitor, C1c secondary side electrolytic capacitor, C2 capacitor, C3 coupling capacitor, D1-D3 diode, R1-R7, R1a, R2a, R7a resistance, L1, L2 inductor, T1 transformer, Q1-Q3 FET, OP operational amplifier, SW switching unit, CT on / off controller, PQ switching circuit control signal generator, CP comparator, DE reference value setting unit, LA lamp, LA1 fluorescent lamp LA2 LED.

Claims (7)

A power rectifier circuit for rectifying the input AC voltage;
A DC power supply circuit having an electrolytic capacitor connected to the power supply rectifier circuit and generating a smoothed voltage;
A lighting circuit that is connected to the electrolytic capacitor and converts the smoothed voltage into a voltage corresponding to the connected lamp to light the lamp;
A life level signal that is connected in parallel to the electrolytic capacitor and detects the ripple voltage of the electrolytic capacitor and reduces the brightness of the lamp when the detected ripple voltage is lower than a preset reference voltage. A life detection circuit that outputs to the lighting circuit;
A lighting device comprising:   The life detection circuit has a counting unit that counts the number of times the detected ripple voltage falls below a preset reference voltage, and outputs a life level signal when the count counted by the counting unit exceeds a preset specified number. The lighting device according to claim 1, wherein: A power rectifier circuit for rectifying the input AC voltage;
A DC power supply circuit having an electrolytic capacitor connected to the power supply rectifier circuit and generating a smoothed voltage;
A lighting circuit that is connected to the electrolytic capacitor and converts the smoothed voltage into a voltage corresponding to the connected lamp to light the lamp;
A life level signal that is connected in parallel with the electrolytic capacitor and detects the ripple voltage of the electrolytic capacitor and reduces the brightness of the lamp when the detected ripple voltage exceeds a preset reference voltage. Life detection circuit that outputs to lighting circuit,
A lighting device comprising:   The life detection circuit has a counting unit that counts the number of times the detected ripple voltage exceeds a preset reference voltage, and outputs a life level signal when the count counted by the counting unit exceeds a preset number of times. The lighting device according to claim 3.   The lighting circuit includes a switching element, and a control circuit that controls ON / OFF of the switching element at a predetermined cycle, and changes a cycle of turning on / off the switching element when the life detection circuit outputs a life level signal. The lighting device according to claim 1, further comprising: an inductor and a capacitor connected to the switching element and configured to limit a current or a voltage supplied to the lamp. The lighting circuit controls the switching element and ON / OFF of the switching element to control a predetermined current to flow through the lamp, and when the life detection circuit outputs a life level signal, A control circuit for controlling the current flowing through the lamp to be less than the predetermined current;
The lighting device according to any one of claims 1 to 4, further comprising: The lighting device according to any one of claims 1 to 6,
An appliance body for fixing the lighting device;
A lighting apparatus comprising:

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