JP2012048981A - Lighting device and lighting apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact lighting device low in power losses and noise, and a lighting apparatus using the same.SOLUTION: An electrodeless-discharge-lamp lighting device comprises an electrodeless discharge lamp 4, an induction coil 3 for inducing an induction magnetic field at the electrodeless discharge lamp 4, a pulse width modulation (PWM) oscillator circuit 5 for outputting a PWM signal according to an external light control signal, and a high-frequency power supply circuit 2 for outputting high-frequency power at the electrodeless discharge lamp 4 responding to the PWM signal from the PWM oscillator circuit 5. The high-frequency power supply circuit 2 comprises a series circuit of switching elements Q2 and Q3 across which an output voltage of a DC power supply circuit 1 is applied, and a driving circuit 20 for alternately turning on and off the switching elements Q2 and Q3 at high frequencies. The switching elements Q2 and Q3 are made of wide bandgap semiconductor devices.

Description

  The present invention relates to an illumination lighting device and a lighting fixture using the same.

  Conventionally, an electrodeless discharge lamp lighting device for dimming and lighting an electrodeless discharge lamp has been provided (see, for example, Patent Document 1). The electrodeless discharge lamp lighting device includes a magnetic core, an induction coil that induces an induction magnetic field in the electrodeless discharge lamp when a high-frequency current is wound around the magnetic core, and a high-frequency voltage applied to the induction coil A high frequency power supply circuit that supplies current and a dimming control circuit that changes a driving frequency of the high frequency power supply circuit in accordance with a dimming signal from the outside. When the dimming control circuit changes the driving frequency of the high-frequency power supply circuit in accordance with the dimming signal input from the outside, the electrodeless discharge lamp is dimmed at a dimming level corresponding to the dimming signal.

Japanese Patent Laying-Open No. 2008-269943 (paragraph [0015] -paragraph [0028] and FIGS. 1 to 4)

  In the electrodeless discharge lamp lighting device disclosed in Patent Document 1 described above, the driving frequency of the high-frequency power supply circuit is set to a high frequency of 100 kHz to several tens of MHz and several tens of GHz, and is set to a higher driving frequency particularly during dimming. Will be. As a result, the power loss in the semiconductor component such as the recovery loss of the diode and the switching loss of the switching element becomes large, which causes a reduction in efficiency.

  In addition, as described above, if the power loss is large, the amount of heat generated by the components also increases, which causes an increase in the size of the device, a complicated heat dissipation structure, deterioration in assembly, design restrictions, and a decrease in heat reliability. ing. Especially in recent years, the progress of practical application of high power LED lighting has been remarkable, and the lineup of electrodeless lighting has been expanded. It has become a big issue. For example, in the case of an electrodeless discharge lamp lighting device with a driving frequency of about a few tens of kHz, the amount of heat generated by a semiconductor element such as a diode or FET becomes considerably large in the class of 100 W or more. It has a complicated heat dissipation structure that is clipped to the side and releases heat generated in the semiconductor element to the outer shell of the case, leading to an increase in the size of the electrodeless discharge lamp lighting device.

  Further, in the conventional Si-based semiconductor device, there is a reverse recovery time of about several tens of ns, and the noise spectrum generation factor (noise terminal voltage, noise power, radiation noise) of this reverse recovery time is about several tens of MHz. Etc.). This noise may cause adverse effects on surrounding devices. Further, in the conventional Si-based semiconductor element, since the reverse recovery time has temperature characteristics, the frequency band of the generated noise spectrum varies with temperature. Therefore, in order to suppress noise in a wider temperature range, noise countermeasures corresponding to a wider frequency band are necessary, which causes an increase in size, structural complexity, and design constraints of the apparatus.

  In the case of a luminaire, it is also known that the noise level changes because the shape affects the noise band of 10 MHz to 30 MHz. For example, it has been confirmed that the electronic ballast is superimposed on the power supply line through the current induced in the appliance from the output side (lamp line side) of the electronic ballast. It has been confirmed that it depends on the way it is taken and the grounding stability. And when said Si type semiconductor element is used, the noise of the band of 10 MHz-30 MHz increases for said reason. Therefore, particularly in a lighting fixture, the increase in noise and the design of the fixture are limited to take measures against the noise. The above phenomenon is a phenomenon observed in a power supply device that operates at a high frequency of several tens of kHz or more, but may be affected even when a casing unrelated to the power supply device happens to be close to the power supply device.

  The problem of noise caused by the semiconductor element is particularly noticeable when dimming control is performed. In this case, the closer to 100% output, the larger the current and the higher the temperature of the semiconductor element. The frequency band of the generated noise spectrum changes significantly due to the temperature characteristics of the semiconductor element, and because it is driven at a higher frequency during dimming, a large number of reverse recovery is also a cause of increasing noise. It has become.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small illumination lighting device with reduced power loss and noise and a lighting fixture using the same.

  The illumination lighting device of the present invention includes a light emitting unit and a circuit unit including a dimming control unit that performs dimming control of the light emitting unit, and at least one of the semiconductor elements constituting the circuit unit is formed of a wide band gap semiconductor. It is characterized by.

  In this illumination lighting device, the circuit unit preferably includes a high frequency power supply circuit that supplies high frequency power to the light emitting unit, and at least one of the switching elements constituting the high frequency power supply circuit is preferably formed of a wide band gap semiconductor.

  The illumination lighting device further includes a control circuit that adjusts a gate voltage or a gate resistance of a switching element made of a wide band gap semiconductor among the switching elements, and the dimming control unit performs dimming control on the light emitting unit. In a state where the dimming is not performed, it is also preferable to increase the gate voltage or lower the gate resistance as compared with the case where the dimming control is performed.

  Furthermore, in this illumination lighting device, the circuit unit has a chopper circuit that supplies power to either the light emitting unit or the high frequency power supply circuit that supplies high frequency power to the light emitting unit, and a diode or a switching element constituting the chopper circuit Is preferably made of a wide band gap semiconductor.

  Further, in this illumination lighting device, a control circuit that adjusts the gate voltage or gate resistance of the switching element constituting the chopper circuit is provided, and the control circuit is in a state where the dimming control unit does not perform dimming control on the light emitting unit. It is also preferable to raise the gate voltage or lower the gate resistance than when the dimming control is performed.

  The lighting fixture of this invention is equipped with said illumination lighting device, It is characterized by the above-mentioned.

  There is an effect that it is possible to provide a small illumination lighting device and a lighting fixture with reduced power loss and noise.

It is a circuit diagram which shows Embodiment 1 of this invention. It is a characteristic view which shows the resonance characteristic same as the above. It is an operation | movement waveform diagram same as the above. An example of the same usage pattern is shown, wherein (a) is a perspective view and (b) is a structural diagram of an electrodeless discharge lamp used therein. An example of the lighting fixture using the same as above is shown, (a) is a perspective view, (b) is a schematic sectional view. The other example of the lighting fixture using the same as the above is shown, (a) is a front view, (b) is a bottom view, and (c) is a left side view. It is a circuit diagram which shows the other example same as the above. It is a circuit diagram which shows the principal part of another example same as the above. It is a circuit diagram which shows another example same as the above. It is a circuit diagram which shows Embodiment 2 of this invention.

  Hereinafter, embodiments of an illumination lighting device and a lighting fixture according to the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a circuit diagram showing an example of an electrodeless discharge lamp lighting device (illumination lighting device) of the present embodiment. The lighting device receives a power supply from a commercial AC power supply 13 and outputs a DC voltage V1. A PWM signal (a dimming signal) V3 is output to the power supply circuit 1, the high frequency power supply circuit 2 that receives power supply from the DC power supply circuit 1 and outputs the high frequency voltage V2, and the drive circuit 20 of the high frequency power supply circuit 2 described later. And a PWM oscillation circuit (a dimming control unit) 5. The lighting device includes an induction coil 3 connected between the output ends of the high-frequency power supply circuit 2 and an electrodeless discharge lamp 4 disposed in the vicinity of the induction coil 3. Here, in the present embodiment, a circuit unit is configured by the DC power supply circuit 1, the high frequency power supply circuit 2, and the PWM oscillation circuit 5, and a light emitting unit is configured by the induction coil 3 and the electrodeless discharge lamp 4.

  The DC power supply circuit 1 includes a rectifier circuit 10 that rectifies the AC output of the commercial AC power supply 13, an inductor L1, a diode D1, a switching element Q1, a smoothing capacitor C1, and a drive circuit 11 that drives the switching element Q1. It consists of a conventionally known step-up chopper circuit.

  The high frequency power supply circuit 2 includes a pair of switching elements Q2 and Q3, a drive circuit 20 that drives the switching elements Q2 and Q3, and a resonance circuit including an inductor L2 and capacitors C2 and C3. By flowing a high frequency current of 10 kHz to several hundred kHz, a high frequency electromagnetic field is generated in the induction coil 3 to supply high frequency power to the electrodeless discharge lamp 4. In response to this, a high-frequency plasma current is generated in the electrodeless discharge lamp 4 to generate ultraviolet rays or visible light. The switching elements Q2 and Q3 are made up of field effect transistors, for example.

  The PWM oscillation circuit 5 generates a PWM signal V3 which is a repetition of ON / OFF of a certain frequency, and its duty (time ratio) is set to a predetermined value. The output of the PWM oscillation circuit 5 is connected to the drive circuit 20 via a resistor and a diode, and the sink current I1 is changed according to the PWM signal V3 to vary the operating frequency (drive frequency of the drive circuit 20) f1.

  The induction coil 3 is wound around a cylindrical coupler 30 as shown in FIG. In the example shown in FIG. 4 (a), the electrodeless discharge lamp lighting device excluding the light emitting portion (induction coil 3 and electrodeless discharge lamp 4) is housed in a metal case 100, and the induction coil 3 is connected via a feeder 100a. Is electrically connected.

  As shown in FIG. 4B, the electrodeless discharge lamp 4 is made of a transparent material such as glass, and has a hollow bulb 40 having a recess 41 on the outer surface and a cylindrical shape made of a synthetic resin, A base 42 attached to the valve 40 so as to surround the opening of the recess 41 is provided, and the coupler 30 is inserted into the recess 41 to be disposed in the vicinity of the induction coil 3. For example, a discharge gas containing an inert gas and a metal vapor is sealed in the bulb 40. Further, an exhaust pipe 41 a inserted into the coupler 30 protrudes from the bottom surface of the recess 41 of the valve 40. Further, a protective film 40a and a phosphor film 40b are provided on the inner surface of the bulb 40. When an arc discharge is generated in the bulb 40 by the high frequency electromagnetic field generated by the induction coil 3, the generated ultraviolet light is converted into visible light in the phosphor film 40b, so that the electrodeless discharge lamp 4 emits light.

  Next, the operation of the lighting device will be described with reference to FIGS. FIG. 2 shows a resonance curve a at the start of the high frequency power supply circuit 2 and a resonance curve b at the time of lighting (steady time). When the PWM signal V3 is at the L level, the operating frequency f1 = f12, and when the PWM signal V3 is at the H level, the operating frequency f1 = f11 (<f12), and the frequency f11 is a high-frequency voltage V2 sufficient for starting the electrodeless discharge lamp 4. The frequency f12 is set so as to generate a high-frequency voltage V2 at which the electrodeless discharge lamp 4 cannot be kept on.

  More specifically with reference to FIG. 3, the high frequency voltage V2 increases by setting the PWM signal V3 = H at time t = t1 (V2 = V22), and the electrodeless discharge lamp 4 at time t = t2. Lights up by performing the initial ignition start. Further, by setting the PWM signal V3 = L at time t = t3, the high-frequency voltage V2 is reduced and the electrodeless discharge lamp 4 is turned off. Further, by setting the PWM signal V3 = H at time t = t4, the high-frequency voltage V2 increases (V2 = V21), and the electrodeless discharge lamp 4 starts re-igniting at time t = t5. Lights on. Further, by setting the PWM signal V3 = L at time t = t6, the high-frequency voltage V2 is reduced and the electrodeless discharge lamp 4 is turned off. Here, as shown in FIG. 3, the maximum voltage V2 = V21 at the re-ignition start is smaller than the maximum voltage V2 = V22 at the initial ignition start, but this remains in the electrodeless discharge lamp 4. This is due to the presence of ions.

  In the same manner, the electrodeless discharge lamp 4 can be blinked by repeating the series of operations in accordance with the PWM signal V3. The electrodeless discharge lamp 4 can be changed by changing the on-duty of the PWM signal V3. 4 outputs can be set arbitrarily. The operating frequency f1 is set to several tens kHz to several hundreds kHz, and the blinking frequency f2 is set to 100 Hz to several kHz so as not to give a flickering feeling to the human eye.

  Here, since the DC power supply circuit 1 and the high-frequency power supply circuit 2 described above have a high driving frequency, the power loss of the semiconductor components constituting the circuits 1 and 2 becomes large, which causes a reduction in efficiency. End up. In addition, as the power loss of semiconductor components increases, the amount of heat generation also increases, which causes an increase in the size of the device, the complexity of the heat dissipation structure, deterioration in assembly, design restrictions, and a decrease in heat reliability. End up.

  Therefore, in the present embodiment, in order to solve the above problem, the diode of the rectifier circuit 10 constituting the DC power supply circuit 1, the diode D1, the switching element Q1, and the switching elements Q2 and Q3 constituting the high frequency power supply circuit 2 are used. In addition, wide band gap semiconductor elements (for example, GaN-based semiconductor elements and SiC-based semiconductor elements) are used. Here, the wide band gap semiconductor is a semiconductor having light elements (B, C, N, O) in the second period of the periodic table as constituent elements, and the band gap (forbidden band) is twice that of the Si-based semiconductor. The above (2.0 eV or more). This wide band gap semiconductor has sufficiently small conduction loss and on-resistance compared to conventional Si-based semiconductors (smaller by one to two digits), and can operate at high temperatures.

  As a result, power loss generated in the DC power supply circuit 1 and the high-frequency power supply circuit 2 can be reduced as compared with the case where a conventional Si-based semiconductor element is used. In addition, the heat loss can be suppressed by reducing the power loss, and the wide band gap semiconductor element can operate at high temperatures, so there is no need to provide a complicated heat dissipation structure as in the conventional example. A small electrodeless discharge lamp lighting device can be provided. Furthermore, simplification of the heat dissipation structure, improvement in assembly, improvement in design flexibility, and improvement in heat reliability can be expected.

  Next, FIG. 5 shows an example of a lighting fixture A according to the present invention. The lighting fixture A has an electrodeless discharge lamp 4 including a bulb 40 formed in a substantially spherical shape with a translucent material, and a lower surface opened. A cylindrical main body 81, a bowl-shaped outer portion 82 disposed on the lower surface side of the main body 81, and a reflector 83 disposed along the inner surface of the outer portion 82.

  The main body 81 is provided with a mounting portion 84 made of a steel plate on the upper surface side, and a socket 90 is disposed near the opening on the lower surface. A base 42 of the electrodeless discharge lamp 4 is attached to the socket 90, and electric wires (not shown) provided on the socket 90 and the base 42 are electrically connected to each other. A lighting circuit 91 for lighting the electrodeless discharge lamp 4 is housed inside the main body 81. Here, in this example, the lighting circuit 91 constitutes an electrodeless discharge lamp lighting device excluding the light emitting portion (induction coil 3 and electrodeless discharge lamp 4).

  The outer portion 82 is expanded in diameter downward from the periphery of the opening provided on the lower surface of the main body portion 81, and the reflection plate 83 is disposed at a predetermined interval on the inner surface side of the outer portion 82. . The reflection plate 83 is formed in a parabolic shape by an aluminum plate. The bulb 40 is inserted into the insertion hole 83a formed at the center, and the light shielding member 86 is disposed above the insertion hole 83a. And the glass panel 85 formed in the disk shape by the transparent tempered glass is arrange | positioned under the reflecting plate 83. FIG.

  FIG. 6 shows another example of the lighting fixture A according to the present invention. The lighting fixture A has a rectangular parallelepiped body 71a made of, for example, stainless steel and has a translucency such as tempered glass. An instrument main body 71 made of a material having a cover 71b that can be freely opened and closed is provided. On the inner bottom surface of the body 71a, for example, a reflecting plate 71c made of aluminum and having a U-shaped cross section for distributing the light of the electrodeless discharge lamp 4 forward is fixed. The light from the electric lamp 4 is emitted forward through the cover 71b. Further, on the inner bottom surface of the body 71a, a coupler (not shown) to which the electrodeless discharge lamp 4 is attached, a case 100 housing an electrodeless discharge lamp lighting device excluding the light emitting portion, and a DC power supply circuit in the case 100 The terminal block 14 electrically connected to 1 is fixed. The terminal block 14 is connected to the other end of an electric wire (not shown) whose one end is connected to the commercial AC power supply 13. The DC power supply circuit 1 is connected to the commercial AC via the electric wire and the terminal block 14. It is electrically connected to the power source 13.

  Here, since the conventional Si-based semiconductor element has a reverse recovery time of about several tens of ns as described above, and further has a temperature characteristic, the noise in the frequency band of about several tens of MHz is present. Is generated. In addition, as described above, the shape of the lighting fixture may affect the noise band of 10 MHz to 30 MHz, and the noise level may change. For example, in the luminaire A shown in FIGS. 5 and 6, when a Si-based semiconductor element is used as a semiconductor element constituting the DC power supply circuit 1 or the high-frequency power supply circuit 2, noise generated in the semiconductor element described above is a lamp. There is a possibility that the noise is superimposed on the power supply line by being guided to the reflection plate 83, the light shielding member 86, the reflection plate 71c and the like via the line and further flowing through the casing in electrical contact therewith.

  On the other hand, in the present embodiment, a wide band gap semiconductor element is used as the semiconductor element, and this wide band gap semiconductor element has reverse recovery time and reverse recovery time temperature characteristics as compared with a Si-based semiconductor element. Since there is almost no noise reduction over a wide temperature range. And the noise of the 10 MHz-30 MHz band induced | guided | derived via a lamp wire can also be suppressed by reducing the noise of the semiconductor element which is a noise source.

  Here, the electrodeless discharge lamp lighting device of the present embodiment is a step dimming type lighting device corresponding to full lighting (FULL lighting) and a dimming ratio of 50%, and the input current at the time of full lighting is dimming Since it becomes about twice the input current at the time of lighting, a large loss difference occurs. For example, when conventional Si-based semiconductor elements are used as the switching elements Q2 and Q3, the temperature at the time of all lighting may be about several tens of degrees Celsius higher than the temperature at the time of dimming lighting. When converted to the temperature characteristics of the reverse recovery time of the element, this corresponds to a shift of the noise spectrum of about several MHz, which means that noise countermeasures must be taken over a wider frequency range.

  On the other hand, in this embodiment, since wide band gap semiconductor elements are used for the switching elements Q2 and Q3 of the high frequency power supply circuit 2, the amount of heat generation can be reduced, and the temperature difference can be reduced. Since there is almost no temperature characteristic of reverse recovery time or reverse recovery time, noise can also be reduced.

  Further, the DC power supply circuit 1 of the present embodiment is a universal power supply corresponding to an input voltage of 100V to 242V, and the input current when using the 100V system is about twice the input current when using the 200V system. Therefore, a large loss difference occurs. For example, when a conventional Si-based semiconductor element is used as the switching element Q1 of the DC power supply circuit 1, the temperature when using the 100V system may be several tens of degrees higher than the temperature when using the 200V system. This corresponds to the fact that the noise spectrum shifts by several MHz when converted to the temperature characteristic of the reverse recovery time of the Si-based semiconductor device, and means that noise countermeasures must be taken for a wider frequency range.

  In contrast, in the present embodiment, since the wide band gap semiconductor element is used for the switching element Q1 of the DC power supply circuit 1, the amount of heat generation can be reduced, the temperature difference can be reduced, and reverse recovery can be achieved. Since there is almost no temperature characteristic of time and reverse recovery time, noise can also be reduced.

  Thus, according to the present embodiment, by using a wide band gap semiconductor element as the semiconductor element constituting the electrodeless discharge lamp lighting device, noise in the tens of MHz band affected by the coupling with the lighting fixture A can be reduced. Can be reduced. In the case of an electrodeless discharge lamp lighting device, it operates at a high frequency of 100 kHz to several tens of MHz and several tens of GHz, so power loss is large and it can be a main noise source, but it has a wide band with good high frequency characteristics. By using a gap semiconductor element, power loss and noise can be effectively reduced. Further, in the coupler 30 of the electrodeless discharge lamp lighting device, structurally, noise from the coupler 30 and noise increase due to the coupling between the coupler 30 and a surrounding housing (for example, a reflector) are likely to be a problem. These noises can be reduced by reducing the noise from the semiconductor elements (diodes D1, switching elements Q1 to Q3, etc.).

  In addition, when a GaN-based semiconductor element is used as the wide band gap semiconductor element, high-frequency characteristics are further improved, so that high efficiency can be achieved. When an SiC-based semiconductor element is used, the on-resistance is low. Since a high breakdown voltage element can be realized, there is an advantage that a higher starting voltage can be applied and the startability is further improved. In particular, even when a re-ignition voltage is generated, such as frequency-modulated light as in this embodiment or intermittent dimming that performs dimming control by repeatedly turning it on and off, reliability against breakdown voltage is ensured. can do.

  FIG. 7 is a circuit diagram showing another example of the electrodeless discharge lamp lighting device (illumination lighting device) of the present embodiment. The lighting device converts an AC voltage output from the commercial AC power supply 13 into a DC voltage. DC power supply circuit 1, high-frequency power supply circuit 2 connected to the output end of DC power supply circuit 1, transformer 6 with primary winding LM1 connected to the output end of high-frequency power supply circuit 2, and secondary winding of transformer 6 A resonance circuit 7 connected to the LM 2 and an induction coil 3 connected to the output terminal of the resonance circuit 7 and disposed in proximity to the electrodeless discharge lamp 4 are provided.

  The DC power supply circuit 1 includes a rectifier circuit 10 that generates a DC voltage by full-wave rectifying the AC voltage output from the commercial AC power supply 13, and a smoothing capacitor C0 that smoothes the rectified voltage.

  The high-frequency power supply circuit 2 is a so-called full-bridge type inverter circuit in which four switching elements are connected in series and parallel. The switching elements Q1 and Q2 connected in series to the output terminal of the DC power supply circuit 1 are also DC Switching elements Q3 and Q4 connected in series to each other at the output terminal of the power supply circuit 1 and a control circuit 20 for controlling on / off of the switching elements Q1 to Q4 are provided. The control circuit 20 includes an oscillation circuit 201 that outputs a rectangular wave signal having a predetermined duty ratio, and a drive circuit 202 that turns on / off the switching elements Q1 to Q4 based on the rectangular wave signal output from the oscillation circuit 201. Prepare. Here, the switching elements Q1 to Q4 are composed of transistors such as FETs, for example. In addition, a dimming control unit is configured by the control circuit 20 described above, and a dimming signal from the outside is input to the oscillation circuit 201.

  In the transformer 6, one end of the primary winding LM1 is connected to the connection point of the switching elements Q1 and Q2, and the other end of the primary winding LM1 is connected to the connection point of the switching elements Q3 and Q4. One end of the LM2 is connected to the same line as the terminal on the ground potential side of the high frequency power supply circuit 2, and the other end of the secondary winding LM2 is connected to the resonance circuit 7.

  The resonance circuit 7 converts the output of the high frequency power supply circuit 2 into a high frequency high voltage of several kV to several tens of kV by a resonance operation, and supplies the high voltage to the induction coil 3 at the start. One end of the coil L1 and the capacitor C1 connected in series between the other end of the line LM2 and the other end of the induction coil 3 is connected to a connection point between the coil L1 and the capacitor C1, and the other end is connected to the ground potential. And the capacitor C2.

  Here, since the high frequency power supply circuit 2 shown in FIG. 7 uses four switching elements Q1 to Q4, there are problems of increased loss, larger size, and increased noise than the high frequency voltage circuit 2 shown in FIG. It becomes more prominent. Therefore, in this example, wide band gap semiconductor elements are used for the switching elements Q1 to Q4 constituting the high-frequency power supply circuit 2, and as a result, the high-frequency power supply circuit 2 can be reduced in loss and noise, The size of the apparatus can be reduced. Since the wide band gap semiconductor element is used for the diode of the rectifier circuit 10 constituting the DC power supply circuit 1 and the switch 15 that is turned on / off in response to the operation of an operation switch (not shown), It is also possible to reduce loss and noise.

  By the way, there is a difference in element temperature between when the electrodeless discharge lamp 4 is fully lit and when it is lit with a dimming ratio of 50%. At this time, the element characteristics change depending on the temperature characteristics, so that control is difficult. There is a case. For example, as shown in FIG. 1, when wide bandgap semiconductor elements are used for the switching elements Q2 and Q3 of the high frequency power supply circuit 2, the gate current increases at high temperatures, so optimal control is performed in all states. Becomes difficult. Therefore, for example, as shown in FIGS. 8A and 8B, the temperature characteristics of the elements are improved by adjusting the gate resistances of the switching elements Q2 and Q3 constituting the high frequency power supply circuit 2 in FIG.

  In the example shown in FIG. 8A, variable resistors VR1 and VR2 are connected between the gate terminals of the switching elements Q2 and Q3 and the output terminal of the drive circuit 20, respectively. The gate resistances of Q2 and Q3 can be adjusted. In the example shown in FIG. 8B, resistors R20 and R21 are connected between the gate terminals of the switching elements Q2 and Q3 and the output terminal of the drive circuit 20, respectively, and the switch 22 is connected in parallel with the resistor R20. And a series circuit of a resistor R22 and a series circuit of a switch 23 and a resistor R23 are connected in parallel with the resistor R21. The gate resistance of the switching elements Q2 and Q3 can be adjusted by a signal from the control circuit 21.

  Specifically, the gate resistance of the switching elements Q2 and Q3 is lower in the state where the PWM oscillation circuit 5 (see FIG. 1) does not perform dimming control of the electrodeless discharge lamp 4, that is, in full lighting. By doing so, the rounding of the gate waveform is eliminated and the power consumption is reduced. As a result, the element temperature difference from that during dimming can be reduced, and the influence of temperature characteristics can be reduced. Further, by reducing the gate resistance of the switching elements Q2 and Q3 during full lighting, the heat generation of the elements can be reduced.

  Furthermore, at the time of dimming in which noise tends to increase, the noise can be reduced by increasing the gate resistance of the switching elements Q2 and Q3 than at the time of non-dimming. In addition, when all the lights are turned on at a high temperature at which the gate current increases, there is an advantage that the gate current can be supplied more easily by lowering the gate resistance than at the time of dimming.

  Here, the power consumption is reduced by lowering the gate resistances of the switching elements Q2 and Q3 at the time of non-dimming (when fully lit) than at the time of dimming. For example, instead of lowering the gate resistance, the gate The voltage may be increased. In this case, since the on-resistance of the switching elements Q2 and Q3 is lowered, the power consumption can be similarly reduced, and as a result, the element temperature difference from the time of dimming can be reduced. And the influence of temperature characteristics can be reduced.

  Furthermore, when dimming control is performed by increasing / decreasing the output V1 of the DC power supply circuit 1 (see FIG. 1), the switching element Q1 constituting the DC power supply circuit 1 also has element characteristics when fully lit and dimmed. Therefore, at the time of all lighting without dimming control in the same manner, the gate resistance of the switching element Q1 is lowered or the gate voltage is increased so that the influence of the temperature characteristics is reduced compared to the case of dimming. Control is sufficient.

  Also, in this case, at the time of dimming, in which noise tends to be large, the noise can be reduced by increasing the gate resistance of the switching element Q1 or lowering the gate voltage than at the time of non-dimming, and further, at the time of full lighting. The heat generation of the element can be reduced by lowering the gate resistance or raising the gate voltage than during dimming. Further, when all the lights are turned on at a high temperature at which the gate current increases, there is an advantage that the gate current can be supplied more easily by lowering the gate resistance or raising the gate voltage than at the time of dimming.

  FIG. 9 is a circuit diagram showing still another example of the electrodeless discharge lamp lighting device (illumination lighting device) of the present embodiment. The lighting device is wound around the magnetic core 30 and supplied with a high-frequency current. An induction coil 3 that induces an induction electric field in the electrode discharge lamp 4, a high-frequency power supply circuit 2 that applies a high-frequency voltage to the induction coil 3 to supply a high-frequency current, and electrodeless discharge while the electrodeless discharge lamp 4 is dimmed. A dimming control circuit (a dimming control circuit) that controls the frequency of the high-frequency voltage in each of the lighting period in which the electric lamp 4 is kept on and the non-lighting period in which the electrodeless discharge lamp 4 cannot be kept on to change the magnitude of the high-frequency voltage. Light control unit) 8. The high-frequency power supply circuit 2, the induction coil 3, and the electrodeless discharge lamp 4 are the same as described above, and detailed description thereof is omitted here.

  The dimming control circuit 8 includes a driver 80 for controlling on / off of the switching elements Q1 and Q2 of the high frequency power supply circuit 2, a capacitor C1 and a resistor R1 connected between the driver 80 and the ground, and the driver 80 and the ground. And a series circuit of a resistor R2 and a switching element Q3 connected in parallel to the resistor R1.

  The driver 80 incorporates an oscillator (not shown), and the switching frequency of the switching element Q3 is switched according to an external dimming signal to change the oscillation frequency. At this oscillation frequency, the rectangular wave switching signal is switched. By alternately outputting to the elements Q1 and Q2, the switching elements Q1 and Q2 are switched to switch the driving frequency of the high-frequency power supply circuit 2. The driver 80 drives the high-frequency power supply circuit 2 during the non-lighting period, that is, does not light up so that the magnitude of the high-frequency voltage applied immediately after switching from the non-lighting period to the lighting period (re-ignition period) is constant. The frequency of the high frequency voltage applied to the induction coil 3 during the period is set.

  The dimming signal for switching the switching element Q3 is, for example, a voltage signal in which H (high) and L (low) are alternately switched, and the ratio of the lighting period and the non-lighting period of the electrodeless discharge lamp 4 by changing the on-duty. To change. The ON / OFF repetition frequency of the dimming signal is set to 100 Hz or more so that the human eye does not feel flicker.

  The oscillation frequency of the driver 80 at this time is determined by the capacitor C1, the resistors R1 and R2, and the switching element Q3. When the switching element Q3 is turned off by the dimming signal, the oscillation frequency becomes a frequency based on 1 / (R1 × C1). When the switching element Q3 is on, the frequency is based on 1 / {(1 / R1 + 1 / R2) × C1}.

  Also in this example, by using wide band gap semiconductor elements for the switching elements Q1 and Q2 constituting the high frequency power supply circuit 2, it is possible to reduce the loss and noise of the high frequency power supply circuit 2 and to reduce the noise of the apparatus. Miniaturization can be achieved.

  Here, in the present embodiment, the frequency-modulable light has been described as an example. For example, frequency dimming that performs dimming control by shifting the driving frequency of the high-frequency power supply circuit 2 to the high frequency side and shifting from the resonance frequency, and on / off May be intermittent light control in which light control is repeated. In the present embodiment, wide band gap semiconductor elements are used for all the semiconductor elements (for example, the diode, the diode D1 and the switching elements Q1 to Q3 of the rectifier circuit 10 in FIG. 1) constituting the DC power supply circuit 1 and the high frequency power supply circuit 2. Although the case where it used was demonstrated, at least any one should just be a wide band gap semiconductor element. Furthermore, the DC power supply circuit 1 may be a universal power supply compatible with 100 V to 277 V including the US 277 V specification. Moreover, although this embodiment demonstrated the case where a light control ratio was 50%, a light control ratio should just be between 0%-100%, and is not limited to this embodiment. Further, in the present embodiment, the step dimming type lighting device has been described as an example, but a continuous dimming type lighting device may be used.

(Embodiment 2)
FIG. 10 is a circuit diagram showing an example of the LED lighting apparatus of the present embodiment. The light emitting unit is composed of a plurality of (four in FIG. 10) light emitting diodes LD1 to LD4, and the circuit is composed of the DC power supply circuit 1 and the filter circuit 9. A part.

  The filter circuit 9 includes a fuse F1, a capacitor C3, and a line filter LF1, and the fuse F1 is connected in series to one end of the commercial AC power supply 13, and the capacitor C3 is connected in parallel with the other end of the commercial AC power supply 13 and the output end of the fuse F1. And a line filter LF1 are connected.

  The DC power supply circuit 1 is a flyback type DC-DC converter, and includes a full-wave rectifier 10 connected to the output terminal of the filter circuit 9, a capacitor C1 connected in parallel with the full-wave rectifier 10, and a capacitor C1. And a series circuit of a switching element Q1 connected between the output terminals of the switching element Q1. The DC power supply circuit 1 includes a first control circuit 11 that controls on / off of the switching element Q1, and a second control circuit 12 that outputs a predetermined feedback signal to the first control circuit 11. Prepare.

  The first control circuit 11 is provided on the primary side of the transformer T1, and outputs a switching signal of the switching element Q1 according to an input value from the feedback terminal FB. The second control circuit 12 is provided on the secondary side of the transformer T1, and generates a feedback signal using as an input signal a value obtained by converting the output current to the light emitting diodes LD1 to LD4 by the resistor R1. The light output element of the photocoupler PC1 is connected to the output of the second control circuit 12, and the light receiving element of the photocoupler PC1 is connected to the feedback input terminal FB of the first control circuit 11. Here, a dimming signal is input from the outside to the first control circuit 11, and the drive frequency of the switching element Q1 is determined according to the dimming signal. That is, in this embodiment, dimming control is performed by increasing or decreasing the output voltage of the DC power supply circuit 1 in accordance with the dimming signal.

  Next, circuit operation will be described. The DC power supply circuit 1 is a so-called flyback type DC power supply device, and is a partial resonance type having a capacitor C4 connected in parallel to the switching element Q1. The voltage input from the commercial AC power supply 13 is input to the filter circuit 9 via the input connector CON1, and is full-wave rectified by the full-wave rectifier 10. The full-wave rectified voltage is applied to the series circuit of the transformer T1 and the switching element Q1 through the capacitor C1. When the switching element Q1 is closed, a current flows through the transformer T1 and is charged as magnetic energy. When the switching element Q1 is opened, the magnetic energy passes through the secondary winding and the diode D1. To the output side.

  The output voltage is smoothed by the capacitor C2 and output through the output connector CON2. The voltage output from the DC power supply circuit 1 is supplied to the light emitting diodes LD1 to LD4, and the light emitting diodes LD1 to LD4 are turned on when the voltage becomes equal to or greater than the total forward voltage of the light emitting diodes LD1 to LD4.

  Here, since the driving frequency of the DC power supply circuit 1 is a high frequency, the power loss of the semiconductor components constituting the DC power supply circuit 1 is increased, resulting in a decrease in efficiency, and the power loss of the semiconductor components is further increased. As the amount of heat generation increases, the size of the device, the complexity of the heat dissipation structure, the deterioration of assemblability, the limitation of the design, and the decrease in the reliability of heat are caused. Therefore, also in this embodiment, in order to solve the above problem, a wide band gap semiconductor element is used for the diode of the rectifier circuit 10 constituting the DC power supply circuit 1, the diodes D1 to D3, and the switching element Q1.

  As a result, the power loss generated in the DC power supply circuit 1 can be reduced as compared with the case where a conventional Si-based semiconductor element is used. In addition, the heat loss can be suppressed by reducing the power loss, and the wide band gap semiconductor element can operate at high temperatures, so there is no need to provide a complicated heat dissipation structure as in the conventional example. A small LED lighting apparatus can be provided. Furthermore, simplification of the heat dissipation structure, improvement in assembly, improvement in design flexibility, and improvement in heat reliability can be expected.

  Here, when the light-emitting diodes LD1 to LD4 are dimmed, the temperatures of the light-emitting diodes LD1 to LD4 change greatly, so that each semiconductor element constituting the DC power supply circuit 1 may be affected. In the embodiment, a wide band gap semiconductor element is used, and the operation is possible even at a high temperature. Therefore, the influence of heat generated from the light emitting diodes LD1 to LD4 can be reduced. Moreover, since the circuit part including the DC power supply circuit 1 can be disposed in the vicinity of the light emitting diodes LD1 to LD4, a small LED lighting apparatus can be provided.

  Here, in this embodiment, dimming control is performed by increasing or decreasing the output voltage of the DC power supply circuit 1 according to a dimming signal from the outside. For example, the output of the DC power supply circuit 1 is turned on / off. PWM dimming for dimming control may be used. Moreover, although this embodiment demonstrated the case where a light emission part was light emitting diode LD1-LD4, organic EL may be sufficient.

1 DC power supply circuit (chopper circuit)
2 High-frequency power circuit 3 Induction coil (light-emitting part)
4 Electrodeless discharge lamp (light emitting part)
5 PWM oscillation circuit (dimming controller)
20 Drive circuit Q2, Q3 Switching element

Claims (6)

  An illumination lighting comprising: a light emitting unit; and a circuit unit including a dimming control unit that performs dimming control on the light emitting unit, wherein at least one of semiconductor elements constituting the circuit unit is formed of a wide band gap semiconductor. apparatus.   2. The circuit unit according to claim 1, wherein the circuit unit includes a high-frequency power supply circuit that supplies high-frequency power to the light-emitting unit, and at least one of the switching elements constituting the high-frequency power supply circuit is made of a wide band gap semiconductor. Lighting lighting device.   A control circuit for adjusting a gate voltage or a gate resistance of a switching element made of a wide bandgap semiconductor among the switching elements, wherein the control circuit is in a state where the dimming control unit does not perform dimming control on the light emitting unit; The illumination lighting device according to claim 2, wherein the gate voltage is increased or the gate resistance is decreased as compared to when the light control is performed.   The circuit unit includes a chopper circuit that supplies power to either the light-emitting unit or a high-frequency power supply circuit that supplies high-frequency power to the light-emitting unit, and a diode or a switching element constituting the chopper circuit has a wide band gap. It consists of a semiconductor, The illumination lighting device of any one of Claims 1-3 characterized by the above-mentioned.   A control circuit that adjusts a gate voltage or a gate resistance of the switching element constituting the chopper circuit, and the control circuit performs dimming control in a state where the dimming control unit does not perform dimming control on the light emitting unit. The illumination lighting device according to claim 4, wherein the gate voltage is increased or the gate resistance is decreased as compared with a case where the operation is performed.   A lighting fixture comprising the illumination lighting device according to any one of claims 1 to 5.

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