JP6070753B2 - Lighting device and lighting apparatus - Google Patents

Description

  The present invention relates to a lighting device and a lighting device.

  Conventionally, various lighting devices for lighting a light emitting element such as a light emitting diode (LED) are known. This type of lighting device includes an AC-DC conversion circuit unit that rectifies and smoothes a commercial AC power supply to generate a DC voltage, and a DC-DC converter unit that supplies an optimal current to the LED from the DC voltage. Many lighting fixtures require a high power factor. Therefore, as shown in Document 1, a two-converter system using a step-up chopper type power factor correction circuit as an AC-DC conversion circuit and a step-down chopper circuit as a DC-DC converter is widely adopted.

  In this case, since two converters, a step-up chopper circuit and a step-down chopper circuit, are required, there are problems that increase the number of parts, increase the size of the circuit board, and increase the cost. Therefore, for example, as disclosed in Patent Documents 2 and 3, a component can be achieved by achieving both power factor improvement control and light source current control with one converter using a flyback converter or a SEPIC (Single Ended Primary Inverter Converter). A method of reducing the number of points and reducing the size of the circuit board has been developed.

JP 2010-40400 A JP 2011-62043 A JP 2011-82204 A

  In the two-converter system, an AC voltage is temporarily converted into a smoothed DC voltage by a step-up chopper circuit and used as an input to the step-down chopper circuit. On the other hand, the one-converter method using one converter such as a flyback converter or a SEPIC does not smooth the full-wave rectified voltage obtained by the rectifier circuit to improve the power factor, but converts it to a component twice the commercial frequency. The pulsating voltage is used as the converter input voltage. For this reason, compared with the two-converter method, the one-converter method tends to generate a pulsation of a component twice the commercial frequency in the current flowing through the light source. Such pulsation of the light source current causes flickering, and this flickering may cause flickering of a camera image even when it is not perceived by human eyes.

  The pulsation of the light source current can be suppressed by using a large-capacity smoothing capacitor at the output. However, when a large-capacity capacitor is used for output, it takes time until the light source is turned on after the power is turned on. That is, when a large-capacity capacitor is used for the output, there is a problem that it takes a long time for the capacitor charging voltage to reach the light source lighting start voltage because the capacitor charging time becomes long.

  The present invention has been made to solve the above-described problems. Even when a large-capacity capacitor is used, the light source can be turned on in a short period of time after the power is turned on, and the pulsation of the light source current causes flickering. An object of the present invention is to provide a lighting device and a lighting fixture capable of suppressing the above.

  A lighting device according to the present invention includes a rectifier circuit that rectifies an AC power supply, a DC power supply circuit that is connected to the rectifier circuit, charges and discharges energy with a switching element and an inductor, and supplies a DC current to a light source, and the DC A control unit that controls a switching operation of the power supply circuit, wherein the DC power supply circuit includes an output terminal to be connected to the light source, a first capacitor that is provided in parallel with the output terminal and smoothes the DC current, A second circuit, a current limiting resistor connected in series with the second capacitor, and a switch circuit connected in parallel with the current limiting resistor, the series circuit including the second capacitor and the current limiting resistor being A capacitor parallel circuit connected in parallel with the first capacitor, and the control unit is configured to switch the light source after the DC power supply circuit starts a switching operation. Period until it lit and shut off the switch circuit, the time after which the light source is turned on, and switches to conduction from the cutoff of the switching circuit. The lighting fixture concerning this invention is equipped with the said lighting device and LED or organic EL element which the said lighting device lights.

  According to the present invention, in a plurality of capacitors connected in parallel with the light source, the number of capacitors contributing to smoothing of the light source current is reduced and the light source is turned on until at least the light source is turned on after the power is turned on. Thereafter, the number of capacitors contributing to smoothing of the light source current is increased, so that the light source can be turned on in a short period of time after the power is turned on, and the pulsation of the light source current that causes flickering can be suppressed.

It is a circuit block diagram of the lighting device concerning Embodiment 1 of this invention. It is an example of the switch circuit of the lighting device concerning Embodiment 1 of this invention. It is a wave form diagram which shows the operation | movement concerning the comparative example with respect to embodiment. It is a wave form diagram which shows operation | movement of the lighting device concerning Embodiment 1 of this invention. It is a connection example of the output capacitor of the lighting device according to the first embodiment of the present invention. It is a circuit block diagram of the lighting device concerning Embodiment 2 of this invention. It is a wave form diagram which shows operation | movement of the lighting device concerning Embodiment 2 of this invention. It is a figure which shows the detail of the control part of the lighting device concerning Embodiment 2 of this invention. It is a wave form diagram which shows control operation of the lighting device concerning Embodiment 2 of this invention. It is a wave form diagram which shows the example of control operation of the lighting device concerning Embodiment 2 of this invention. It is a wave form diagram which shows the example of control operation of the lighting device concerning Embodiment 2 of this invention. It is a wave form diagram which shows the example of control operation of the lighting device concerning Embodiment 2 of this invention. It is a circuit block diagram of the lighting device concerning Embodiment 3 of this invention. It is a wave form diagram which shows control operation of the lighting device concerning Embodiment 3 of this invention. It is sectional drawing of the lighting fixture in Embodiment 4 of this invention.

  A lighting device and a lighting fixture according to an embodiment of the present invention will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repeated description may be omitted.

Embodiment 1 FIG.
FIG. 1 is a circuit configuration diagram of a lighting device 100 according to the first embodiment of the present invention. The lighting device 100 receives power supplied from the AC power source 1 and turns on the light source 50. The lighting device 100 includes a rectifier circuit 2, a converter unit 3, and a control unit 4. The rectifier circuit 2 rectifies the AC power supply. Specifically, the AC voltage input from the AC power supply 1 is full-wave rectified. This full-wave rectified voltage is not smoothed during the operation of the converter unit 3 and becomes a pulsating voltage including twice the frequency of the AC power supply 1.

  In the first embodiment, an LED (Light Emitting Diode) is used as the light source 50.

  A converter unit 3 is connected to the rectifier circuit 2. The converter unit 3 includes a filter capacitor C1 and an inductor L1, for example, a switching element SW1 formed of a MOSFET, a coupling capacitor C2, an inductor L2, a diode D1, and output smoothing capacitors C3a and C3b. The converter unit 3 is a SEPIC (Single Ended Primary Inductor Converter) circuit constituted by these circuit elements. The output of the converter unit 3 is connected to the light source 50 via the output terminal 102 of the lighting device 100. The output smoothing capacitor C3a is connected in parallel to the output terminal 102 of the lighting device 100, and is also connected in parallel with the light source 50. The converter unit 3 further includes a current limiting resistor R2 connected in series to the output smoothing capacitor C3b, and a switching element SW2 provided in parallel with the current limiting resistor R2. A parallel circuit composed of the current limiting resistor R2 and the switching element SW2 is connected in series to the output smoothing capacitor C3b, and a series-parallel circuit is configured by these three circuit elements. This series-parallel circuit is connected in parallel with the output smoothing capacitor C3a and also in parallel with the light source 50.

  The inductor L1 includes a primary winding L1a and a secondary winding L1b that is magnetically coupled to the primary winding L1a. The inductor L1 and the inductor L2 may be wound around individual cores (magnetic cores), or both the inductor L1 and the inductor L2 may be wound around one core to share the core.

  A light source current detection resistor R1 is provided between the output smoothing capacitor C3a and the GND line. Here, the light source current detection resistor R1 is provided at a position where the total charging current of the output smoothing capacitors C3a and C3b is detected. However, the position where the total discharge current of the output smoothing capacitors C3a and C3b is detected, that is, the light source current in series with the light source 50 is provided. A detection resistor R1 may be provided. Since the average current value of the total charging current and the total discharging current of the output smoothing capacitors C3a and C3b is equal, the current value flowing through the light source can be detected from any current.

  Converter unit 3 operates under the control of control unit 4. The converter unit 3 converts the voltage that has been full-wave rectified by the rectifier circuit 2 into a DC current and a DC voltage suitable for lighting the light source 50. The control unit 4 includes a voltage comparison unit 5, a zero current detection unit 6, a drive unit 7, and an output capacitor control unit 8. The control unit 4 drives and controls the switching element SW1 so that the average value of the current flowing through the light source 50 becomes a target current value.

  The voltage comparison unit 5 averages the signal generated in the light source current detection resistor R1, compares it with the target signal E1 corresponding to the target light source current, and outputs a signal corresponding to the difference between the two signals. The drive unit 7 receives the signal from the voltage comparison unit 5 and determines the ON time of the switching element SW1.

  The zero current detection unit 6 receives a signal from the secondary winding L1b of the inductor L1, and after the switching element SW1 is turned off, the total current of the inductor L1 and the inductor L2 flowing to the load side via the diode D1 becomes zero. Detect that When the zero current detection unit 6 detects that the current flowing to the load side becomes zero by a signal from the secondary winding L1b, the drive unit 7 turns on the switching element SW1. Note that a zero current may be detected by providing a secondary winding in the inductor L2 instead of the secondary winding L1b.

  The output capacitor control unit 8 performs on / off control of the switching element SW2, that is, control for switching between conduction and interruption of the switching element SW2. When the switching element SW2 is turned on (that is, conductive), both ends of the current limiting resistor R2 are short-circuited by the switching element SW2. The switching element SW2 is equivalent to a MOSFET having a parasitic diode connected in antiparallel. When a transistor or IGBT having no parasitic diode is used as the switching element SW2, as shown in FIG. 2, the diode D2 is connected in antiparallel with the switching element SW2, and output smoothing is not performed through the current limiting resistor R2. Capacitor C3b is allowed to discharge.

  Next, operation | movement of the lighting device 100 concerning Embodiment 1 is demonstrated.

  When the AC power source 1 is applied to the lighting device 100, the rectifier circuit 2 performs full-wave rectification on the input AC voltage, and the rectified voltage is applied to both ends of the filter capacitor C1. The filter capacitor C1 is provided for the purpose of removing the switching ripple, and is not for smoothing the frequency component of the AC power supply 1 here. Therefore, during operation of the converter unit 3, a full-wave rectified voltage that pulsates at twice the power supply frequency is applied to the converter unit 3.

  The operation of the converter unit 3 in the steady operation state will be described. The switching element SW1 is turned on by the drive unit 7. When the switching element SW1 is turned on, the AC power supply 1 is short-circuited via the inductor L1, so that a current is supplied through the path between the inductor L1 and the switching element SW1, and energy is stored in the inductor L1. At this time, the current of the inductor L1 increases.

  At the same time, the voltage of the coupling capacitor C2 is applied to the inductor L2. For this reason, a current flows through the path of the coupling capacitor C2, the switching element SW1, and the inductor L2, and the energy of the coupling capacitor C2 is stored in the inductor L2. At this time, the current of the inductor L2 increases.

  When the ON time of the switching element SW1 set by the drive unit 7 has elapsed, the switching element SW1 is turned off. When the switching element SW1 is turned off, the energy stored in the inductor L1 is released, and a current flows through the path of the inductor L1, the coupling capacitor C2, the diode D1, and the output smoothing capacitor C3a or C3b. As a result, the coupling capacitor C2 and the output smoothing capacitors C3a and C3b can be charged.

  At the same time, the energy stored in the inductor L2 is released, and a current flows through the path of the inductor L2, the diode D1, and the output smoothing capacitor C3a or C3b. Thereby, the output smoothing capacitors C3a and C3b are charged. In this way, energy is transmitted to the load side, and finally, direct current is supplied from the output smoothing capacitors C3a and C3b to the light source 50, and the light source 50 emits light. The switching element SW1 repeats this operation at high speed. For example, the driving frequency of the switching element SW1 is several tens kHz to several hundreds kHz.

  The current flowing through the light source 50 is detected as a voltage signal by the light source current detection resistor R1, and the detected voltage signal is input to the voltage comparison unit 5 and averaged. If the average voltage generated by the light source current detection resistor R1 is higher than the target signal E1, the voltage comparison unit 5 adjusts the output signal in a direction that shortens the ON time of the switching element SW1. In response to this, the driving unit 7 operates in a direction to decrease the on-time of the switching element SW1, and decreases the current of the light source 50. If the average voltage generated by the light source current detection resistor R1 is lower than the target signal E1, the voltage comparison unit 5 adjusts the output signal in a direction in which the ON time of the switching element SW1 becomes longer. In response to this, the driving unit 7 operates in a direction to increase the on-time of the switching element SW1, and increases the current of the light source 50. Thus, constant current feedback control is performed so that the average current value of the light source 50 becomes the target current value.

  Next, it will be described that the light source current pulsates with a frequency component twice that of the AC power source 1.

  When the switching element SW1 is turned on, the current IL1 of the inductor L1 is proportional to the instantaneous value E of the full-wave rectified voltage and inversely proportional to the inductance L1 of the inductor L1. That is, the current IL1 of the inductor L1 rises substantially linearly in proportion to the on-time with a slope of E / L1.

  FIG. 3 shows a current waveform of the inductor L1 and a voltage waveform of the AC power supply 1 when the on-time t (ON) of the switching element SW1 is fixed and the AC power supply 1 is operated for a half cycle (since it is a full-wave rectified waveform). . Since the inductance L1 is a constant value, the peak value of the current of the inductor L1 in each switching period is proportional to the power supply voltage. Therefore, as shown in the figure, the envelope has a sinusoidal waveform.

  Since the energy stored in the inductor is proportional to the square of the current value, the amount of energy input to the output side is small when the voltage of the AC power source 1 is near the zero cross, and the amount of energy input to the output side is near the peak voltage of the AC power source 1. Becomes larger. Therefore, the current of the light source 50 decreases when the voltage of the AC power source 1 is near zero cross, and the current of the light source 50 increases when the voltage of the AC power source 1 is near the peak, so that the current pulsates at twice the frequency of the AC power source 1. May cause flicker.

  Further, the control unit 4 performs constant current feedback control in order to supply the target current to the light source 50. However, if it is attempted to suppress the pulsation of the light source current by constant current feedback, the control unit 4 is within a half cycle of the AC power source 1. The on-time of the switching element SW1 varies greatly due to the constant current feedback control, and the envelope of the current peak value of the inductor L1 does not have the sine wave shape as shown in FIG. May decrease and the harmonic current of the input current may increase.

  Therefore, in general, the response time of the constant current feedback control is set so that the loop gain of the constant current feedback control is greater than or equal to 1/2 of one cycle of the AC power supply 1 and less than or equal to 1 (0 dB). In other words, the response time is set so that it is 1 (0 dB) or less at a frequency 2 times or less of the frequency of the AC power supply 1. For example, when the power supply frequency is 50 Hz, the constant current feedback control is controlled by setting the loop gain of the constant current feedback control to 1 (0 dB) or less in a half cycle (half wave) of 100 Hz or less, that is, a cycle of 10 ms or more. It sets so that it may not respond with a period shorter than 1/2 of a period. As a result, the fluctuation of the ON time of the switching element SW1 is suppressed within a half cycle of the power supply cycle, and the envelope of the current peak value of the inductor L1 becomes a sinusoidal waveform. That is, as shown in FIG. 3, the ON time of the switching element is substantially fixed in a half cycle period of one cycle of the AC power supply 1. Therefore, the pulsation of the light source current twice the frequency of the AC power supply 1 cannot be smoothed by the constant current feedback control.

  Therefore, in the first embodiment, in order to suppress the pulsation of the light source current, a plurality of output smoothing capacitors C3a and C3b are mounted on the output side to increase the combined capacity of the output capacitors. Then, a current limiting resistor R2 and a switching element SW2 connected in parallel with the resistor R2 are connected in series with the output smoothing capacitor C3b, and this operation will be described with reference to FIG.

  Assume that the AC power supply 1 is turned on at time t0 in FIG. At this time, it is assumed that the charges accumulated in the output smoothing capacitors C3a and C3b are zero and the voltage is zero. When the AC power source 1 is turned on, the converter unit 3 starts to operate, so that a current flows through the output smoothing capacitors C3a and C3b, and charging is started. Accordingly, the voltage across the output smoothing capacitors C3a and C3b increases. Since the switching element SW2 is in the OFF state during the period from t0 to t1 in FIG. 4, the output smoothing capacitor C3b is charged via the current limiting resistor R2. Accordingly, since the charging current is limited by the current limiting resistor R2, the voltage gradually increases with time as compared with the output smoothing capacitor C3a. Further, during this period, since the voltage of the output smoothing capacitor C3a whose voltage rises quickly does not reach the lighting start voltage of the light source 50, the light source 50 is turned off.

  Next, at time t1 in FIG. 4, the voltage of the output smoothing capacitor C3a reaches the lighting start voltage of the light source 50, and the light source current starts to flow. At this time, since the voltage of the output smoothing capacitor C3b is charged through the current limiting resistor R2, it does not reach the lighting start voltage of the light source 50. Therefore, no current is supplied from the output smoothing capacitor C3b to the light source 50. In the period from t0 to t1 in FIG. 4, since the voltage of the output smoothing capacitor C3b is lower than the voltage of the output smoothing capacitor C3a, the output smoothing capacitor C3b does not contribute to reducing the pulsation of the light source current, and the output smoothing capacitor C3a Only contributes to the smoothing of the light source current. Note that the light source current waveform in FIG. 4 is originally a waveform in which pulsations at twice the frequency of the AC power supply 1 are superimposed, but in FIG. 4, pulsation drawing is omitted.

  Next, at time t2 in FIG. 4, the voltage of the output smoothing capacitor C3b becomes almost the same voltage as the output smoothing capacitor C3a. Then, the output capacitor control unit 8 outputs a signal for turning on the switching element SW2. As a result, the switching element SW2 is turned on and the current limiting resistor R2 is short-circuited by the switching element SW2, and thereafter, the output smoothing capacitor C3b can be charged without going through the current limiting resistor R2. As a result, the output smoothing capacitors C3a and C3b are connected in parallel without equivalent resistance in the equivalent circuit, and the light source current is smoothed by the combined capacity of the output smoothing capacitors C3a and C3b. Compared with the light source current, the pulsating component of the double frequency of the AC power source 1 is reduced.

  Next, the effect of switch switching control by the switching element SW2 will be described. Since the switching element SW2 is in an off state when the AC power supply 1 is turned on, the output smoothing capacitor C3b is charged via the current limiting resistor R2, so that the charging current is limited and the voltage rise takes time. That is, since the charging current to the output smoothing capacitor C3b is sufficiently small due to the limitation of the current limiting resistor R2, most of the energy discharge currents of the inductor L1 and the inductor L2 of the converter unit 3 contribute to the charging of the output smoothing capacitor C3a. Thereby, the voltage rise time of the output smoothing capacitor C3a is accelerated, and the time from when the AC power source 1 is turned on until the light source 50 is turned on can be increased.

  However, since the output smoothing capacitor C3b does not contribute to the smoothing of the light source current in this state, the pulsation of the light source current is large. Therefore, in the first embodiment, when the voltage of the output smoothing capacitor C3b reaches almost the same voltage as that of the output smoothing capacitor C3a over time, the switching element SW2 is turned on to short-circuit the resistor R2. As a result, the light source current is smoothed by the combined capacity of the output smoothing capacitors C3a and C3b, and the light source 50 can be turned on with a small pulsation current, and flickering can be suppressed. In the first embodiment, the switching element SW2 is turned on after the voltage of the output smoothing capacitor C3b rises to substantially the same voltage as the output smoothing capacitor C3a. However, the present invention is not limited to this. After the light source 50 is turned on, the switching element SW2 may be turned on before the voltage of the output smoothing capacitor C3b reaches the voltage of the output smoothing capacitor C3a. Also in such a case, the time from when the power source 1 is turned on until the light source 50 is turned on can be increased, and the light source current can be smoothed. Variations of control for switching the switching element SW2 will be described later.

  However, when the switching element SW2 is turned on while the voltages of the two capacitors are almost balanced, the charging / discharging current between the capacitors due to the voltage imbalance between the two output smoothing capacitors C3a and C3b is suppressed when the switching element SW2 is turned on. can do. If the switching element SW2 is turned on in a state where the voltage of the output smoothing capacitor C3b is lower than the voltage of the output smoothing capacitor C3a, and a parallel state is established, a steep charging current flows from the output smoothing capacitor C3a to the output smoothing capacitor C3b. Further, the voltage of the output smoothing capacitor C3a decreases, the current of the light source 50 becomes unstable, and flickering may occur. In the first embodiment, as a preferred form capable of suppressing such a phenomenon, the light source 50 waits until the voltage of the two capacitors is balanced even after the light source 50 is turned on, and then the switching element SW2 is turned on. .

  As described above, according to the control unit 4 according to the first embodiment, the switching element SW2 is turned off during the period from when the converter unit 3 starts the switching operation of the switching element SW1 to when the light source 50 is turned on. By setting (cut off), the output smoothing capacitor C3b can be charged via the current limiting resistor R2. In addition, after the light source 50 is turned on, the output smoothing capacitor C3b can be charged via the switching element SW2 by turning on the switching element SW2. Thereby, when the AC power supply 1 is turned on, the output capacitor can be quickly activated (that is, the light source is turned on) with the output capacitor having an equivalently small capacity so as to give priority to the time until the light source starts to turn on. Further, since the capacitance of the output capacitor is equivalently large in the normal lighting state after the light source is turned on, the double frequency pulsating flow of the AC power source 1 can be suppressed.

  Here, a variation of the control for switching the switching element SW2 will be described. The condition for switching the switching element SW2 from OFF (blocking) to ON (conduction) after the light source is turned on may be based on whether or not the voltage of the output smoothing capacitor C3b has reached the voltage of the output smoothing capacitor C3a. As a specific example, either (1) voltage condition or (2) time condition described below may be set.

  (1) First, a method for setting a condition (that is, a voltage condition) for switching the switching element SW2 by detecting a voltage in the circuit will be described. For determining whether or not the voltage of the output smoothing capacitor C3b has reached the voltage of the output smoothing capacitor C3a, a voltage detection unit (not shown) is provided in the lighting device 100, and this voltage detection unit is connected to the output capacitor control unit 8. May be. The voltage detection means may directly compare the voltage of the output smoothing capacitor C3a and the voltage of the output smoothing capacitor C3b. Alternatively, the saturation value (V3a in FIG. 4) of the charging voltage of the output smoothing capacitor C3a is determined in advance in the circuit design with the switching element SW2 turned off, and the output smoothing capacitor C3b is always set by the current limiting resistor R2. Under the condition that the battery is charged later than C3a, only the voltage of the output smoothing capacitor C3b may be detected. In this case, the predetermined smoothing value set to the same value as the charging voltage saturation value V3a of the output smoothing capacitor C3a is compared with the voltage of the output smoothing capacitor C3b, so that the output smoothing capacitor C3a and the output smoothing capacitor C3b are compared. The voltage comparison may be performed indirectly. When performing the comparison, the switching element SW2 is turned on when the difference between the voltage of the output smoothing capacitor C3a (or a predetermined predetermined determination value) detected by the voltage detecting means and the voltage of the output smoothing capacitor C3b becomes zero. If the difference is within a predetermined range even if it is not zero, it is assumed that the voltages of the output smoothing capacitors C3a and C3b are substantially the same, in other words, substantially the same, and the switching element SW2 May be turned on. Furthermore, as another modification, the switching element SW2 may be turned on when the voltage of the output smoothing capacitor C3b becomes a high voltage to some extent, even though the voltage of the output smoothing capacitor C3a has not been reached. For example, the lower limit of the predetermined range may be set to a predetermined lower threshold that is set lower than the charging voltage saturation value V3a. When the voltage of the output smoothing capacitor C3b reaches this lower threshold, the switching element SW2 is turned on. You may set the conditions to do. This lower limit threshold value may be set to a desired value, for example, a predetermined ratio obtained by multiplying the charging voltage saturation value V3a of the output smoothing capacitor C3a by a predetermined coefficient (for example, 95 of the charging voltage saturation value V3a of the output smoothing capacitor C3a). %, 90%, 85%,... 60%, etc.).

  (2) Next, a method for setting a condition (that is, a time condition) for measuring the elapsed time from a specific circuit operation or the like and switching the switching element SW2 based on the elapsed time will be described. A time length from a predetermined starting point to a time point when the voltage of the output smoothing capacitor C3a and the voltage of the output smoothing capacitor C3b substantially match is obtained in advance by theoretical calculation or experiment. When the elapsed time from the starting point reaches the time length obtained in advance, the control unit 4 may send a signal to the output capacitor control unit 8 so as to turn on the switching element SW2. In this case, the control unit 4 may have a timer function for measuring time. The method of determining the starting point will be described. After the time point t0 when the converter unit 3 starts the switching operation of the switching element SW1, and before the time point when the voltage of the output smoothing capacitor C3a and the voltage of the output smoothing capacitor C3b coincide with each other. In addition, an arbitrary starting point may be set in advance. The starting point may be the time point t0 in FIG. 4, and in this case, the timer of the control unit 4 may measure the time from the start of the switching operation of the switching element SW1. The time length from t0 to the predicted time when the voltage of the output smoothing capacitor C3a and the voltage of the output smoothing capacitor C3b coincide with each other is calculated in advance by theoretical calculation or the like and stored in a memory (not shown) of the control unit 4. May be. As one of other modifications, the starting point may be the light source lighting time point t1. In that case, the light source current may be detected by providing a light source current detection resistor R1 in series with the light source 50 and then detecting a signal generated in the light source current detection resistor R1, and the output smoothing capacitor from time t1. You may memorize | store in the memory of the control part 4 the time length to the prediction timing when the voltage of C3a and the voltage of the output smoothing capacitor C3b correspond. In addition, the detection of the light source lighting time t1 is not necessarily limited to the electrical parameters of the converter unit 3 and may be based on a detection signal of the optical sensor in the case where an optical sensor that detects the lighting of the light source 50 is provided. As another modification, the starting point may be a point in time when the voltage value of the output smoothing capacitor C3a reaches a predetermined constant value. In this case, the starting point is provided between t0 and t1.

  As described above, the conditions for turning on the switching element SW2 are exemplified, but the present invention is not necessarily limited to the above-described voltage conditions and time conditions. When the power is turned on, the switching element SW2 is turned off and then the switching element SW2 is turned on at a desired timing, so that the capacity of the output capacitor is equivalently reduced when the AC power supply 1 is turned on. It is possible to obtain an effect that the capacitance of the can be increased equivalently.

  In the present embodiment, an example in which two output smoothing capacitors are used has been described. However, the present invention is not limited to this, and according to the time until the light source starts to light or according to the pulsation of the light source current. The output smoothing capacitor may be further increased. For example, as shown in FIG. 5, an output smoothing capacitor C3c may be added in parallel with the output smoothing capacitor C3b. The high potential side terminal of the output smoothing capacitor C3c is connected to the high potential side terminal of the output smoothing capacitor C3b. The low potential side terminal of the output smoothing capacitor C3c is connected to the low potential side terminal of the output smoothing capacitor C3b and the current limiting resistor R2. It is connected to the connection point. In this case, since the switching element SW2 and the current limiting resistor R2 can be shared with respect to the output smoothing capacitors C3b and C3c, an increase in the number of components can be suppressed.

  Further, in this embodiment, the SEPIC system lighting device has been described as an example. However, other systems may be used, and for example, the present invention can be applied to a buck-boost converter system and a flyback converter system, and similar effects can be obtained.

  Moreover, although the case where the light source 50 used LED was demonstrated in this Embodiment, it is not limited to this. For example, an organic EL (Electro Luminescence) element may be used as the light emitting element of the light source.

Embodiment 2. FIG.
FIG. 6 is a circuit configuration diagram of the lighting device 110 according to the second embodiment of the present invention. Components similar to those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. The lighting device 110 according to the second embodiment includes a power supply voltage detection resistor R3 and a power supply voltage detection unit 9, and the drive unit 7 suppresses a ripple component that vibrates at a frequency component twice the commercial frequency, and a light source current. Is different from the lighting device 100 of the first embodiment in that the switching element SW1 is driven so as to be smoothed.

  The control unit 4 controls the average value of the current flowing through the light source 50 to a target current value, suppresses a ripple component that vibrates at a frequency component twice the commercial frequency, and smoothes the light source current. Thus, the switching element SW1 is driven.

  The power supply voltage detection unit 9 detects the phase of the AC power supply 1 from the voltage signal generated in the power supply voltage detection resistor R3, and the drive unit 7 receives the output signals of the voltage comparison unit 5 and the power supply voltage detection unit 9 to detect the switching element SW1. Determine the on-time.

  Next, the operation of the lighting device 110 according to the second embodiment will be described.

  First, an operation in the case where the light source 50 is turned on while the output capacitor control unit 8 is turning off the switching element SW2 will be described. In a state where the switching element SW2 is off, the output capacitor contributing to smoothing of the light source current is only C3a, so that the pulsation of the light source current is large.

  Therefore, in the second embodiment, in order to suppress the pulsation of the light source current, the switching element SW1 is changed so that the on-time of the switching element SW1 changes according to a preset pattern according to the voltage phase of the AC power supply 1. To drive. FIG. 7 shows an example of the relationship between the voltage phase of the AC power supply 1 and the ON time of the switching element SW1. Thus, the ON time of the switching element SW1 is decreased when the phase of the AC power supply 1 is near the voltage peak, and the ON time is increased when the phase of the AC power supply 1 is near the zero cross. That is, as the full-wave rectified voltage on the output side of the rectifier circuit 2 is lowered, the on-time of the switching element SW1 is increased, the amount of energy supplied to the output side is increased, and the decrease in the light source current is suppressed. As the value increases, the ON time of the switching element SW1 is reduced, and the amount of energy supplied to the output side is reduced. Such on-time increase / decrease control of the switching element SW1 is hereinafter also referred to as “ripple suppression control”.

  FIG. 8 shows an example of a detailed block diagram of the control unit 4 that realizes ripple suppression control. The voltage comparison unit 5 constitutes an error amplifier including a phase compensation circuit including an operational amplifier 5a, a capacitor 5b, and a resistor 5c. If the signal detected by the light source current detection resistor R1 input to the inverting input terminal side of the operational amplifier 5a is larger than the target signal E1, the output signal of the operational amplifier 5a decreases, and the light source current detection resistor R1 If the detected signal is smaller, the output signal of the operational amplifier 5a increases.

  The drive unit 7 includes a multiplier 7a, a comparator 7b, a flip-flop circuit 7c, an oscillator 7d, and a drive circuit 7e. The multiplier 7 a multiplies the output signal of the voltage comparison unit 5 and the output signal of the power supply voltage detection unit 9. The power supply voltage detection unit 9 obtains the phase of the power supply voltage from the voltage signal generated in the power supply voltage detection resistor R3, and generates a waveform to be input to the multiplier 7a according to the phase. For example, the voltage signal 1− | 0.5 * sin θ | is generated. Here, θ is the voltage phase of the AC power supply 1, and has a waveform synchronized with the power supply voltage as shown in FIG. Here, when the phase angle of the AC power supply 1 is 90 degrees and 270 degrees, the signal voltage of the power supply voltage detector 9 is the lowest, and when the phase angle of the AC power supply 1 is 0 degrees, 180 degrees, and 360 degrees, the power supply voltage is detected. The signal voltage of the unit 9 is the highest.

  The output of the multiplier 7a is input to the inverting input terminal of the comparator 7b and compared with the output signal of the oscillator 7d connected to the non-inverting input terminal of the comparator 7b. The oscillator 7d outputs a sawtooth triangular wave signal. In the oscillator 7d, the signal waveform is reset by the signal of the zero current detection unit 6 including the comparator 6a and the reference voltage 6b, that is, becomes 0V, and rises again. The signal of the zero current detection unit 6 is input to the set terminal S of the flip-flop circuit 7c. The output of the comparator 7b is connected to the reset terminal R of the flip-flop circuit 7c. The output signal of the output terminal Q of the flip-flop circuit 7c is connected to the drive circuit 7e and converted into a signal for driving the switching element SW1 by the drive circuit 7e, and the switching element SW1 is driven by this signal. The control unit 4 may be realized by software control using a microcomputer or the like. When implemented by software control, the arithmetic processing unit, the arithmetic program to be executed by the arithmetic processing unit, the memory storing the parameters to be used for the arithmetic program, and the voltage value etc. as digital values if necessary An A / D conversion circuit for conversion may be included.

  Next, the detailed operation of the drive unit 7 will be described. First, it is assumed that the switching element SW1 is turned on, and the currents of the inductors L1 and L2 increase with time. The output signal of the oscillator 7d rises with time, and when the voltage level of the output signal of the multiplier 7a is exceeded, the comparator 7b outputs a HIGH signal (for example, 5V). As a result, the HIGH signal is input to the reset terminal R of the flip-flop circuit 7c, and the output terminal Q of the flip-flop circuit 7c outputs a LOW signal (for example, 0 V). In response to this, the drive circuit 7e turns off the switching element SW1.

  When the switching element SW1 is turned off, the energy stored in the inductors L1 and L2 is released to the output side. A voltage proportional to the output voltage, that is, the voltage applied to the light source 50 is generated in the secondary winding L1b of the inductor L1, and is input to the inverting input terminal of the comparator 6a. At this time, the voltage is higher than the reference voltage 6b, and a LOW signal is output from the output of the comparator 6a.

  When the inductors L1 and L2 finish releasing the energy, the discharge current to the output side, that is, the current of the diode D1, becomes zero, and the voltage of the secondary winding L1b of the inductor L1 rapidly decreases. When the voltage of the secondary winding voltage L1b falls below the reference voltage 6b, the output of the operational amplifier 6a outputs a HIGH signal. Then, the output signal of the oscillator 7d is reset to 0V, and at the same time, the HIGH signal is input to the set terminal S of the flip-flop circuit 7c, so that the output terminal Q of the flip-flop circuit 7c outputs the HIGH signal. In response to this, the drive circuit 7e turns on the switching element SW1. As a result, the currents of the inductors L1 and L2 begin to flow again, and the output of the oscillator 7d that has been reset to zero starts to rise.

  Here, since the next switching cycle starts after the current of the diode D1 becomes zero due to the energy emission of the inductors L1 and L2, loss due to the recovery characteristic of the diode D1 can be reduced. Further, since the next switching cycle is started immediately after the current of the diode D1 reaches zero, there is no period in which an oscillating voltage due to the parasitic capacitance of the inductor L1 and the switching element SW1 is generated, and noise is generated from the converter unit 3. There is an advantage that is small.

  As described above, the ON time of the switching element SW1 is determined based on the comparison result of the signals of the oscillator 7d and the multiplier 7a. Here, the constant current feedback control of the light source current will be described. First, as described above, the target signal voltage E1 is compared with the detection signal from the light source current detection resistor R1 input to the inverting input terminal side of the operational amplifier 5a. . If the detection signal of the light source current detection resistor R1 is smaller than the target signal E1, the output voltage of the operational amplifier increases with time, and the ON time of the switching element SW1 changes in an increasing direction. If the detection signal of the light source current detection resistor R1 is larger than the target signal E1, the output voltage of the operational amplifier 5a decreases with time, and the ON time of the switching element SW1 changes in a decreasing direction.

  However, as described above, the response speed of the constant current feedback control is slowed down so that it does not respond at least during the half cycle of the AC power supply 1, so that the output voltage of the operational amplifier 5a is considered to be substantially constant during the half cycle of the AC power supply 1. be able to. Therefore, the output signal of the multiplier 7a is a voltage signal substantially proportional to the output signal of the power supply voltage detection unit 9. As a result, the switching element SW1 is not affected by the constant current feedback control, and is driven with an on-time substantially proportional to the output signal of the power supply voltage detector 9. Therefore, since the switching element can be accurately controlled according to the phase of the AC power supply, ripples in the light source current can be reliably suppressed. The response speed of the constant current feedback control can be set by a constant of a phase compensation circuit including the capacitor 5b and the resistor 5c.

  When suppressing the light source current ripple by constant current feedback control, it is necessary to speed up the response of constant current feedback control, but as mentioned above, there is a possibility that the input current waveform is large and the distortion power factor is deteriorated. By speeding up the response, the operation becomes unstable, the worst control oscillates, and the light source may flicker and the lighting device may be broken. In the present invention, since the response time of the constant current feedback control is set to be 1/2 or more times one cycle of the AC power supply, stable operation is possible.

  Thus, the capacitance of the output capacitor is equivalently reduced by decreasing the on-time of the switching element SW1 as the output voltage of the rectifier circuit 2 increases, and increasing the on-time as the output voltage of the rectifier circuit 2 decreases. Even when the switching element SW2 is OFF, the pulsation of the light source current can be reduced.

  Note that the ripple suppression control is control that modulates the on-time of the switching element SW1 in a direction in which the input current harmonics increase in comparison with the control shown in FIG. When the ripple suppression control is performed, the input current waveform is distorted as compared with the case where the ripple suppression control is not performed. After the voltage of the output smoothing capacitor C3b reaches the voltage of the output smoothing capacitor C3a, the switching element SW is turned on by the output capacitor control unit 8, so that the capacity of the output capacitor is equivalently increased and the pulsation of the light source current can be reduced. . Therefore, after the switching element SW2 is turned on, the ripple suppression control may be stopped, or the amplitude of the output signal of the power supply voltage detector 9 may be reduced. That is, by reducing the control amount of the ripple suppression control, it is possible to suppress an increase in input current harmonics during normal lighting.

  FIG. 10 shows an example of the output signal amplitude of the power supply voltage detector 9. FIG. 10 illustrates curves a and b as output signal amplitudes of the power supply voltage detector 9. As described above with respect to the operation of the lighting device 110, there is a proportional relationship between the ON time of the switching element SW1 and the value of the output signal of the power supply voltage detection signal 9. In FIG. 10, when the curve a having a large amplitude is output to the power supply voltage detection unit 9, the ON time variation of the switching element SW1 increases. When the fluctuation of the on-time is large as shown by the curve a, the pulsation suppressing effect of the light source current is increased, but the distortion of the input current waveform is increased. On the other hand, if the power supply voltage detection unit 9 outputs the curve b having a relatively small amplitude, the variation in the ON time of the switching element SW1 is also reduced. When the variation in the on-time is small as in the curve b, the pulsation suppressing effect of the light source current is small, but the distortion of the input current waveform can be reduced. A straight line c is a signal waveform when the ripple suppression control is not performed.

  When the switching element SW2 is off (cut off), the switching element SW1 is preferably driven according to the curve a, and when the switching element SW2 is on (conductive), the switching element SW1 is preferably driven according to the curve b or the straight line c. . That is, in a half cycle of the AC power supply, “a value obtained by dividing the longest on-time of the switching element SW1 by the shortest on-time” when the switching element SW2 is off is “the value of the switching element SW1 when the switching element SW2 is on”. It is preferable to set a value larger than a value obtained by dividing the longest on time by the shortest on time. For convenience, a value obtained by dividing the longest on time of the switching element SW1 by the shortest on time of the switching element SW1 (that is, “longest on time / shortest on time”) is also referred to as “on time variation ratio”. Incidentally, when the control is performed using the straight line c, the on-time variation ratio becomes 1 as the minimum because the on-time is constant in the half cycle of the AC power supply.

  In the present embodiment, the output signal waveform of the power supply voltage detection unit 9 is a waveform having a sine wave peak protruding downward as shown by the curves a and b shown in FIG. Is not limited to this. If the ON time of the switching element SW1 is short in the portion where the instantaneous value of the output voltage of the rectifier circuit 2 is high, and the ON time of the switching element is set long in the portion where the instantaneous value of the output voltage of the rectifier circuit 2 is low good. Therefore, the present invention is not limited to the curved waveform as shown in FIG. For example, a triangular wave as shown in FIG. 11 or a trapezoidal waveform as shown in FIG. 12 may be used, and these waveforms also have an effect of reducing the pulsation of the light source current. As with the curves a and b whose amplitudes are different from each other in FIG. 10, in the triangular wave of FIG. 11, a plurality of amplitudes (that is, positions of the bottom vertexes on the vertical axis of FIG. 11) are different from each other. The power supply voltage detector 9 may be configured so that the triangular wave can be switched. This is the same in FIG. 12, and also in the trapezoidal wave of FIG. 12, a plurality of trapezoidal waves having different amplitudes (that is, the bottom base position of the trapezoidal wave on the vertical axis in FIG. 12) can be switched. The power supply voltage detection unit 9 may be configured. The plurality of triangular waves or trapezoidal waves are selectively used in the same manner as the curves a and b are selectively used according to the on / off state of the switching element SW2. That is, when the switching element SW2 is off, the switching element SW1 is driven according to a waveform having a larger amplitude, and when the switching element SW2 is on, the switching element SW1 is driven according to a waveform having a smaller amplitude or a straight line. You may provide the power supply voltage detection part 9 which can switch a some triangular wave or trapezoid wave.

  In this embodiment, the power supply of the SEPIC method is described as an example. However, other methods can be used as long as the power factor improvement (harmonic current reduction) and constant current control are performed by one converter. For example, the same effect can be obtained also in the buck-boost converter method and the flyback converter method.

  Moreover, although the case where the light source 50 used LED was demonstrated in this Embodiment, it is not limited to this. For example, an organic EL (Electro Luminescence) element may be used as the light emitting element of the light source.

Embodiment 3 FIG.
FIG. 13 is a circuit configuration diagram of the lighting device 120 according to the third embodiment of the present invention. The same configurations as in the second embodiment or the similar configurations to the second embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate. The lighting device 120 according to Embodiment 3 includes a dimming signal interface 10 that reads a dimming signal from the dimming controller 11 provided outside the lighting device 120 in order to control the brightness of the light source 50. This is different from the lighting device 110 of the second embodiment.

  The dimming signal interface 10 receives the dimming signal and adjusts the signal voltage of the target signal E1 to be a signal corresponding to the target current. Further, the output signal of the power supply voltage detector 9 is controlled according to the target current.

  Next, the operation of the lighting device 120 according to the third embodiment will be described.

  As in the second embodiment, the lighting device 120 drives the converter unit 3 under the control of the control unit 4, and the target current determined by the target signal E1 is supplied to the light source 50. In addition, the control unit 4 performs the ripple suppression control so that the ON time of the switching element SW <b> 1 becomes a preset pattern according to the voltage phase of the AC power supply 1.

  Here, in the third embodiment, the switching element on-time pattern of the ripple suppression control is changed according to the dimming signal input from the dimming controller 11, that is, the target light source current. That is, the dimming signal interface 10 that has received the dimming signal from the dimming controller 11 sends a signal that specifies the amplitude of the output signal to the power supply voltage detector 9 in accordance with the dimming signal.

  FIG. 14 shows an output example of the output signal of the power supply voltage detector 9 corresponding to the dimming rate. In the all-light state where the light output is the highest, the energy consumption at the light source 50 is large, so the pulsation of the light source current also increases. Therefore, in the third embodiment, the dimming signal interface 10 that has received the dimming signal designating the all-light state sends a signal to cause the power supply voltage detection unit 9 to output the waveform indicated by the curve a in FIG. The amplitude of the output signal of the power supply voltage detector 9 is increased. According to the curve a, it is possible to increase the rate of change between the on-time of the switching element near the zero cross of the power supply voltage and the on-time of the switching element near the power supply voltage peak.

  When the light source current is small, the energy consumption at the light source is small, so the pulsation of the light source current is small. Therefore, in the third embodiment, when the light source current is made relatively small, more specifically, for example, when a dimming signal for reducing the light source current to a predetermined first predetermined current value less than the total light state is received. In other words, the dimming signal interface 10 sends a signal so as to cause the power supply voltage detection unit 9 to output the waveform shown by the curve b in FIG. In this way, when the light source current is reduced by dimming, the amplitude of the output signal of the power supply voltage detector 9 is reduced. Thereby, the rate of change between the ON time of the switching element near the zero cross of the power supply voltage and the ON time of the switching element near the power supply voltage peak can be reduced.

  In the third embodiment, when the light source current is further reduced, more specifically, when a dimming signal that is narrowed below the first predetermined current value smaller than the second predetermined current value is received, The dimming signal interface 10 sends a signal so as to cause the power supply voltage detection unit 9 to output a constant value indicated by a straight line c in FIG. 14, and sets the output signal of the power supply voltage detection unit 9 to a signal level of a constant value. At this time, the on-time of the switching element near the zero cross of the power supply voltage is substantially equal to the on-time of the switching element near the power supply voltage peak. That is, ripple suppression control is not performed. As described above, in the dimming signal interface 10 according to the third embodiment, the light source current specified by the current dimming signal belongs to one of the three light source current ranges divided into large, medium, and small. Accordingly, an instruction signal is issued to the power supply voltage detector 9 as to which of the output signals of the curves a and b and the straight line c should be generated.

  According to the switching of the curves a and b and the straight line c described above, the “value obtained by dividing the longest on time by the shortest on time” of the switching element SW1 when the light source current is large in the half cycle of the AC power supply It can be set larger than “a value obtained by dividing the longest on time by the shortest on time” of the switching element SW1 when the current is small. For convenience, a value obtained by dividing the longest on-time of the switching element SW1 by the shortest on-time is also referred to as “on-time variation ratio”. In a half cycle of the AC power supply, the on-time variation ratio when the light source current is large is set larger than the on-time variation ratio when the light source current is small. Further, when the ripple suppression control is not performed (straight line c in FIG. 14), the on-time is constant in the half cycle of the AC power supply, and therefore, the value obtained by dividing the longest on-time of the switching element SW1 by the shortest on-time ( In other words, the on-time fluctuation ratio is 1 as a minimum. As shown in FIG. 3, the harmonics of the input current are reduced when the on-time of the switching element is as constant as possible during the period of ½ cycle of the AC power supply 1.

  As described above, in the third embodiment, the output signal of the power supply voltage detection unit 9 is variable according to the dimming rate, that is, the light source current. When the light source current is large, the power supply voltage detection unit 9 sets an output signal so that the suppression of the pulsation of the light source current has priority. When the light source current is small, the power supply voltage detection unit 9 prioritizes the suppression of harmonics of the input current. Set the output signal so that Thereby, generation | occurrence | production of the input current harmonic in the light control area | region where the flicker by a pulsation does not become a problem can be suppressed. The control method shown in the third embodiment can be applied when the switching element SW2 is in an on state or an off state. That is, since the pulsation state of the light source current is different between the dimming state when the switching element SW2 is in the off state and the dimming state when the switching element SW2 is in the on state, independent ripple suppression control can be performed.

  Note that the lighting device 120 according to the third embodiment includes “the output smoothing capacitor C3b, the current limiting resistor R2, the switching element SW2, and the output capacitor control unit 8” as in the first and second embodiments. However, the “output smoothing capacitor C3b, the current limiting resistor R2, the switching element SW2, and the output capacitor control unit 8” may be omitted from the lighting device 120. Even in that case, the technical aspect of the third embodiment in which “the dimming signal input from the dimming controller 11, that is, the pattern of the switching element on time of the ripple suppression control is changed according to the target light source current”. A lighting device with features is provided.

  In the third embodiment, the output signal waveform of the power supply voltage detection unit 9 is a waveform having a sine wave peak convex downward as shown in FIG. 14, but the present invention is not limited to this. is not. The power supply voltage detection so that the on-time of the switching element SW1 is short in the portion where the instantaneous value of the output voltage of the rectifier circuit 2 is high and the on-time of the switching element SW1 is long in the portion where the instantaneous value of the output voltage of the rectifier circuit 2 is low The output signal waveform of the unit 9 may be set. Therefore, the waveform is not limited to the waveform shown in FIG. 14, and may be, for example, a triangular wave as shown in FIG. 11 or a trapezoidal waveform as shown in FIG. 12. These waveforms also have an effect of reducing the pulsation of the light source current. A plurality of triangular waves or trapezoidal waves having different amplitudes are switched in the power supply voltage detection unit 9 in the same manner as the curves a and b are selectively used according to the dimming signal. That is, when the dimming signal is changed so as to increase the light source current, the switching element SW1 is driven according to a waveform having a large amplitude, and when the dimming signal is changed so as to reduce the light source current. The power supply voltage detector 9 may switch between a plurality of triangular waves or trapezoidal waves so that the switching element SW1 is driven according to a waveform or a straight line having a small amplitude.

  Further, in the third embodiment, the power supply of the SEPIC method has been described as an example. However, other methods can be used as long as the power factor improvement (harmonic current reduction) and constant current control are performed by one converter. For example, the same effect can be obtained also in the buck-boost converter method and the flyback converter method.

  Moreover, in Embodiment 3, although the case where the light source 50 used LED was demonstrated, it is not limited to this. For example, an organic EL (Electro Luminescence) element may be used as the light emitting element of the light source.

Embodiment 4
FIG. 15 is a cross-sectional view of lighting apparatus 200 according to Embodiment 3 of the present invention. The lighting fixture 200 includes a lighting fixture body 40, a connector 41, a light source substrate 42, and a lighting device 43. The luminaire main body 40 is a housing for attaching the lighting device 43 and the like. The connector 41 is a connection part for receiving power supply from an AC power source such as a commercial power source. The light source substrate 42 is a substrate on which a light emitting element such as an LED or an organic EL element is mounted as an electrical light source.

  Electric power from an AC power source is input to the lighting device 43 via the connector 41 and the wiring 44. The lighting device 43 is connected to the light source substrate 42 via the wiring 45. The lighting device 43 converts the input power into power to be supplied to the light source board 42 and supplies the converted power to the light source board 42. The light source of the light source substrate 42 is turned on by power supplied from the lighting device 43.

  The circuit configuration of the lighting device 43 is the same as that of the lighting device 100 according to the first embodiment described above. Thereby, the lighting device 43 and the lighting fixture 200 provided with the advantage of the lighting device 100 concerning Embodiment 1 are provided.

  The circuit configuration of the lighting device 43 may be the same as any one of the lighting devices 110 and 120 according to the second and third embodiments.

  According to the lighting apparatus 200 according to the fourth embodiment, the lighting apparatus can be reduced in size, cost, and efficiency by incorporating any one of the lighting devices 100 to 120 described in the first to third embodiments. The time from when the AC power is turned on until the light source is turned on can be increased, and the flickering of the light source can be suppressed.

1 AC power supply, 2 rectifier circuit, 3 converter unit, 4 control unit, 5 voltage comparison unit, 5a operational amplifier, 5b capacitor, 5c resistance, 6 zero current detection unit, 6a comparator, 6a operational amplifier, 6b reference voltage, 7 drive unit, 7a multiplier, 7b comparator, 7c flip-flop circuit, 7d oscillator, 7e drive circuit, 8 output capacitor controller, 9 power supply voltage detector, 10 dimming signal interface, 11 dimming controller, 40 lighting fixture body, 41 connector, 42 light source board, 43 lighting device, 44, 45 wiring, 50 light source, 100, 110, 120 lighting device, 102 output end, 200 lighting fixture, C3a, C3b, C3c output smoothing capacitor, R1 light source current detection resistor, R2 current limit Resistor, R3 Power supply voltage detection resistor

Claims (10)

A rectifier circuit for rectifying an AC power supply;
A DC power supply circuit connected to the rectifier circuit, charging and discharging energy with a switching element and an inductor, and supplying a DC current to the light source;
A control unit for controlling the switching operation of the DC power supply circuit;
With
The DC power supply circuit is
An output end to be connected to the light source;
A first capacitor provided in parallel with the output terminal for smoothing the direct current;
A second circuit, a current limiting resistor connected in series with the second capacitor, and a switch circuit connected in parallel with the current limiting resistor, the series circuit including the second capacitor and the current limiting resistor being A capacitor parallel circuit connected in parallel with the first capacitor;
With
The control unit shuts off the switch circuit during a period from when the DC power supply circuit starts a switching operation until the light source is turned on, and after the time when the light source is turned on, the switch circuit is turned off to turn on. Lighting device that switches between.   The control unit performs the switching of the switch circuit when a difference between the voltage of the first capacitor and the voltage of the second capacitor after the time when the light source is turned on becomes zero or within a predetermined range. The lighting device according to claim 1 to be performed. The control unit has a timer function for measuring time,
After the time when the DC power supply circuit starts the switching operation and within a period before the time when the voltage of the first capacitor and the voltage of the second capacitor coincide with each other, Preset,
The lighting device according to claim 1, wherein the control unit performs the switching of the switch circuit when a predetermined time has elapsed from the starting point.   The lighting device according to claim 1, wherein the second capacitor includes two or more capacitors connected in parallel.   The control unit is configured to instantaneously output the output voltage of the rectifier circuit every ½ cycle of the AC power supply during a period from when the DC power supply circuit starts a switching operation to when the switching of the switch circuit is performed. The lighting device according to claim 1, wherein when the value increases, the on-time of the switching element is decreased, and when the instantaneous value of the output voltage of the rectifier circuit decreases, the on-time of the switching element is increased. . When a value obtained by dividing the longest on-time of the switching element by the shortest on-time of the switching element within a half cycle of the AC power supply is an on-time variation ratio,
The said control part sets the said ON time fluctuation ratio before performing the said switching of the said switch circuit larger than the said ON time fluctuation ratio after performing the said switching of the said switch circuit. Lighting device. The controller is
Receive the dimming signal,
Control the operation of the DC power supply circuit so that the current supplied to the light source becomes a target value according to the dimming rate indicated by the dimming signal,
When the instantaneous value of the output voltage of the rectifier circuit rises every half cycle of the AC power supply, the on-time of the switching element is decreased, and when the instantaneous value of the output voltage of the rectifier circuit falls, the switching element is turned on. Has on-time increase / decrease control to increase time,
In the on-time increase / decrease control, the switching is performed such that an on-time variation ratio, which is a value obtained by dividing the longest on-time of the switching element by the shortest on-time of the switching element, decreases as the current supplied to the light source decreases. The lighting device of any one of Claims 1-4 which adjusts the ON time of an element.   The lighting device according to claim 6 or 7, wherein a minimum value of the on-time variation ratio is 1.   The lighting fixture provided with the lighting device of any one of Claims 1-8, and LED which the said lighting device lights.   The lighting fixture provided with the lighting device of any one of Claims 1-8, and the organic EL element which the said lighting device lights.

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