JP2014235778A - Erroneous operation prevention circuit, illumination light source, and illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an erroneous operation prevention circuit capable of preventing generation of an erroneous operation such as a flicker at turning off light, and of turning off a light source with certainty.SOLUTION: Provided is an erroneous operation prevention circuit 150 that prevents an erroneous operation of a control circuit 130 that is actuated to make a light-emitting element 22 emit light when a predetermined current flows by being applied with an input voltage from a DC power supply circuit 110. The erroneous operation prevention circuit 150 is connected between a positive output terminal and a negative output terminal of the DC power supply circuit 110, and when applied with the input voltage, becomes in a first resistance state to actuate the control circuit 130. When applied with a voltage smaller than the input voltage, the erroneous operation prevention circuit 150 becomes in a second resistance state having a resistance value smaller than that in the first resistance state, and pulls in at least a part of a current supplied from the DC power supply circuit 110 to the control circuit 130 so as not to operate the control circuit 130.

Description

  The present invention relates to a malfunction prevention circuit, and more particularly, to a malfunction prevention circuit applied to an illumination light source using a light emitting diode (LED).

  Light emitting diodes (LEDs) are expected to be a new light source in various devices such as fluorescent lamps and incandescent lamps such as incandescent lamps, because of their high efficiency and long life. Research and development of an illumination light source using this LED is underway. Along with this, development of a drive circuit for driving the LED is also underway (see, for example, Patent Document 1).

US Pat. No. 7,701,153

  In such a drive circuit, malfunction such as flicker may occur due to leakage current or the like when the light is turned off.

  Therefore, the present invention provides a malfunction prevention circuit and the like that can prevent a malfunction such as flickering when the lamp is turned off, and can reliably turn off the light source.

  In order to achieve the above object, a malfunction prevention circuit according to an aspect of the present invention is a control that activates a light emitting element when a predetermined current flows by applying an input voltage from a DC power supply circuit. A malfunction prevention circuit for preventing malfunction of a circuit, which is connected between a positive output terminal and a negative output terminal of the DC power supply circuit and is in a first resistance state when the input voltage is applied When the control circuit is activated and a voltage smaller than the input voltage is applied, a second resistance state having a resistance value smaller than that of the first resistance state is obtained, and the DC power supply circuit transfers the control circuit to the control circuit. The control circuit is not operated by drawing at least part of the supplied current.

  For example, the malfunction prevention circuit has a first resistor, one end connected to the positive output terminal, and the other end connected to the negative output terminal, and the first current path. And a second current path having one end connected to the positive output terminal and the other end connected to the negative output terminal. When a voltage is applied, the first current path is turned on to enter the first resistance state, and when a voltage smaller than the input voltage is applied, the second current path is turned on and the first current path is turned on. 2 may be in a resistance state.

  For example, the first current path further includes a first switching element, the second current path further includes a second switching element, and the malfunction prevention circuit includes the input voltage. Is applied, the first switching element is turned on to conduct the first current path, and when a voltage smaller than the input voltage is applied, the second switching element is turned on. The second current path may be conducted.

  For example, the control circuit is connected between the positive output terminal and the negative output terminal of the DC power supply circuit, and the resistance value when the malfunction prevention circuit is in the second resistance state is the control circuit The resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal may be smaller.

  For example, the resistance value when the malfunction prevention circuit is in the second resistance state is the resistance value of the control circuit from the end connected to the positive output terminal to the end connected to the negative output terminal. It may be 1/20 or less of the resistance value.

  For example, the control circuit is connected between a positive output terminal and a negative output terminal of the DC power supply circuit, and the resistance value when the malfunction prevention circuit is in the first resistance state is the control circuit The resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal may be larger.

  For example, the resistance value when the malfunction prevention circuit is in the second resistance state may be equal to or less than 1/20 of the resistance value when the malfunction prevention circuit is in the first resistance state. Good.

  For example, the first current path further includes a third resistor, the malfunction prevention circuit further includes a fourth resistor and a fifth resistor, and one end of the first resistor is The other end of the first resistor is connected to one end of the third resistor and one end of the fourth resistor, and one end of the second resistor is connected to the positive output terminal. The other end of the second resistor is connected to the collector of the second switching element, and the other end of the third resistor is connected to the collector of the first switching element and the second The other end of the fourth resistor is connected to the base of the first switching element and one end of the fifth resistor, the emitter of the first switching element, the 2 switching element emitters, and the fifth The other end of the resistor may be connected to the negative output terminal.

  An illumination light source according to an aspect of the present invention includes the malfunction prevention circuit according to any one of the above aspects, the control circuit, and the light-emitting element.

  An illumination device according to one embodiment of the present invention includes the illumination light source according to the above embodiment.

  According to the present invention, it is possible to prevent a malfunction such as flickering from occurring when the light is turned off, and to reliably turn off the light source.

FIG. 1 is a diagram showing a circuit configuration of a driving circuit for a conventional illumination light source. FIG. 2 is a side view of the light bulb shaped lamp according to the first embodiment. FIG. 3 is a cross-sectional view of the light bulb shaped lamp according to the first embodiment. FIG. 4 is a diagram illustrating a circuit configuration of the drive circuit according to the first embodiment. FIG. 5 is a diagram for explaining the operation of the malfunction prevention circuit when the LED is lit. FIG. 6 is a diagram for explaining the operation of the malfunction prevention circuit when the LED is turned off. FIG. 7 is a diagram illustrating a circuit configuration of the drive circuit according to the second embodiment. FIG. 8 is a schematic cross-sectional view of the illumination device according to the third embodiment.

(Knowledge that became the basis of the present invention)
In a drive circuit used for an illumination light source, a malfunction such as flickering of the light source may occur due to leakage current when the illumination light source is turned off. Hereinafter, the principle of occurrence of malfunction will be described with reference to FIG.

  FIG. 1 is a diagram showing a circuit configuration of a driving circuit for a conventional illumination light source.

  In the drive circuit 40a shown in FIG. 1, when an input voltage Vin having a predetermined value is input from the first rectifier circuit 110 to the inverter control circuit 130a, a current flows into the capacitor C3, and the operating voltage is held at both ends of the capacitor C3. Is done. As a result, the trigger diode TD breaks over and becomes conductive. Since the trigger diode TD is connected to the base of the switching element Q2 that is the control terminal of the inverter 120, the operation of the inverter 120 is started when the trigger diode TD becomes conductive. That is, the LED 22 emits light.

  On the other hand, when the light is turned off, the voltage held across the capacitor C3 usually does not reach the operating voltage. For this reason, the trigger diode TD is not in a conductive state, and the operation of the inverter 120 is not started, so the LED 22 does not emit light.

  However, when leakage current flows into the first rectifier circuit, a voltage smaller than a predetermined value is input from the first rectifier circuit 110 to the inverter control circuit 130a, and the voltage across the capacitor C3 reaches the operating voltage. There is a case. In such a case, the trigger diode TD is turned on to start the operation of the inverter 120, and the LED 22 emits light. At the same time, the voltage input to the inverter control circuit 130a decreases, and thus the LED 22 is turned off. These repetitions cause a malfunction of flickering of the illumination light source when the light is turned off.

  Such a leakage current that causes a malfunction is likely to occur particularly when the switch circuit 160 including a so-called firefly switch (semiconductor switch) shown in FIG. 1 is connected. In addition, since the conventional bulb-type fluorescent lamp has a high starting voltage, flicker due to leakage current hardly occurs. However, in a light emitting element such as an LED, flicker due to leakage current tends to occur because the starting voltage is low.

  Therefore, the present invention provides a malfunction prevention circuit and the like that can prevent a malfunction such as flickering when the lamp is turned off, and can reliably turn off the light source.

  Hereinafter, an illumination light source and an illumination device to which the malfunction prevention circuit according to the present embodiment is applied will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement positions and connection forms of components, and steps (steps) and order of steps shown in the following embodiments are merely examples, and the present invention is limited. It is not the purpose to do. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements. Each figure is a schematic diagram and is not necessarily illustrated strictly.

  In the following embodiments, a bulb-type LED lamp (LED bulb) will be described as an example of a light source for illumination.

(Embodiment 1)
(Overall configuration of bulb-type lamp)
First, the overall configuration of the light bulb shaped lamp 1 according to Embodiment 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a side view of the light bulb shaped lamp according to the first embodiment. FIG. 3 is a cross-sectional view of the light bulb shaped lamp according to the first embodiment.

  As shown in FIG. 2, the light bulb shaped lamp 1 according to the first embodiment is a light bulb shaped LED lamp that is a substitute for a light bulb shaped fluorescent light or an incandescent light bulb, and includes a globe 10, a housing 60, and a base 70. An envelope is configured.

  As shown in FIG. 3, the light bulb shaped lamp 1 includes a globe 10, an LED module 20, a support base 30 that supports the LED module 20, a drive circuit 40 that drives the LED module 20 (LED 22), and a drive circuit 40. A circuit holder 50 that holds the power, a housing 60 that is configured to surround the drive circuit 40, and a base 70 that receives power from the outside.

  In FIG. 3, the alternate long and short dash line drawn in the vertical direction on the paper indicates the lamp axis J (central axis) of the light bulb shaped lamp. In Embodiment 1, the lamp axis J coincides with the globe axis. ing. The lamp axis J is an axis serving as a rotation center when the light bulb shaped lamp 1 is attached to a socket of an illumination device (not shown), and coincides with the rotation axis of the base 70.

(Glove)
As shown in FIG. 3, the globe 10 is a translucent cover that covers the LED module 20, and is configured to extract light emitted from the LED module 20 to the outside of the lamp. Therefore, the light of the LED module 20 that has entered the inner surface of the globe 10 passes through the globe 10 and is extracted outside the globe 10.

  The globe 10 is a hollow rotating body having an opening. In the first embodiment, the globe 10 is configured in a substantially hemispherical shape with a narrowed opening. As shown in FIG. 3, the opening of the globe 10 is in contact with the support base 30. The opening, the support base 30, and the housing 60 are fixed by an adhesive (not shown) such as silicone resin.

  The globe 10 may be transparent so that the internal LED module 20 can be visually recognized, or the globe 10 may not be transparent by providing the globe 10 with a light diffusion function. When the globe 10 has a light diffusing function, for example, a milky white light diffusing film is formed by applying a resin or a white pigment containing a light diffusing material such as silica or calcium carbonate to the entire inner surface or outer surface of the globe 10. What is necessary is just to form.

  As a material of the globe 10, a glass material such as silica glass, or a resin material such as acrylic (PMMA) or polycarbonate (PC) can be used. Note that the globe 10 may have the same shape as the incandescent bulb.

(LED module)
The LED module 20 is a light emitting module having a light emitting element, and emits light of a predetermined color (wavelength) such as white. As shown in FIG. 3, the LED module 20 is mounted on the support base 30 and emits light by the power supplied from the drive circuit 40.

  As shown in FIG. 3, the LED module 20 includes a substrate 21 and an LED 22 mounted on the substrate 21. The LED module 20 in the first embodiment is configured using an SMD (Surface Mount Device) type LED 22.

  The substrate 21 is a mounting substrate for mounting the LEDs 22. The substrate 21 is, for example, a ceramic substrate made of ceramics such as alumina, a resin substrate, or a metal base substrate, and a plate-like substrate having a substantially rectangular or circular shape in plan view can be used.

  The substrate 21 is attached to the support base 30 so that the back surface is in surface contact with the front surface of the support base 30. Although not shown, a plurality of electrode terminals are provided on the surface of the substrate 21, and lead wires led out from the drive circuit 40 are solder-connected to each of the electrode terminals. Further, metal wiring for electrically connecting the electrode terminals and the plurality of LEDs 22 is formed on the surface of the substrate 21 in a pattern.

  Each LED 22 is an example of a light emitting element, and emits light with a predetermined power. The LED 22 in the first embodiment is an SMD type light emitting element. For example, a resin container having a recess, an LED chip mounted in the recess, and a sealing member (phosphor) enclosed in the recess. Containing resin).

  For example, a blue LED chip that emits blue light when energized can be used as the LED chip. In this case, as the sealing member, a silicone resin containing YAG-based yellow phosphor particles can be used. As a result, part of the blue light emitted from the LED chip is converted into yellow light by the yellow phosphor particles contained in the sealing member, and the wavelength of the blue light and the yellow phosphor particles that are not absorbed by the yellow phosphor particles. The converted yellow light is mixed and emitted as white light.

(Support stand)
The support base 30 (module plate) is a support member that supports the LED module 20, and the LED module 20 is placed thereon. The support base 30 is configured to close the opening of the globe 10. The support base 30 also functions as a heat radiating member (heat sink) for radiating heat generated by the LED module 20 (LED 22). In order to efficiently conduct heat, the support base 30 may be made of a metal material mainly composed of aluminum (Al), copper (Cu), iron (Fe), or the like, or a resin material having high thermal conductivity. preferable. In the first embodiment, the support base 30 is made of aluminum. The support base 30 is fixed to the housing 60.

(Drive circuit)
The drive circuit (circuit unit) 40 is a lighting circuit for causing the LED module 20 (LED 22) to emit light (lights), and supplies predetermined power to the LED module 20. For example, the drive circuit 40 converts AC power supplied from the base 70 into DC power, and supplies the DC power to the LED module 20.

  The drive circuit 40 is composed of a plurality of circuit elements (not shown) for driving the LED module, and is provided on the main surface of the circuit board 41. In the following description, the circuit element is also referred to as a circuit component.

  The circuit board 41 is a printed circuit board (PCB board) in which a metal wiring such as a copper foil is patterned on one surface (solder surface). The plurality of circuit elements mounted on the circuit board 41 are electrically connected to each other by metal wiring. The circuit board 41 has a plurality of through holes into which lead wires (legs) of circuit elements are inserted.

  In the first embodiment, the circuit board 41 is attached to the circuit holder 50 in a posture (vertical arrangement) in which the normal line of the main surface of the circuit board 41 is substantially orthogonal to the lamp axis J. The circuit board 41 in the first embodiment is in contact with only the circuit holder 50 and is held only by the circuit holder 50.

  Circuit elements (circuit components) include, for example, capacitive elements such as electrolytic capacitors and ceramic capacitors, resistive elements such as resistors, rectifier circuit elements, coil elements, choke coils (choke transformers), noise filters, diodes, integrated circuit elements, etc. The semiconductor element or the like. Many of the circuit elements are mounted on one main surface of the circuit board 41. Details of the circuit configuration of the drive circuit will be described later.

  The drive circuit 40 and the LED module 20 are electrically connected by a pair of lead wires (output-side lead wires). The drive circuit 40 and the base 70 are electrically connected by a pair of lead wires (input side lead wires). These four lead wires are, for example, alloy copper lead wires, and are composed of a core wire made of alloy copper and an insulating resin film covering the core wire.

(Circuit holder)
The circuit holder 50 is a holding member for holding the drive circuit 40, and is configured so that at least a part thereof is disposed between the support base 30 and the drive circuit 40. The circuit holder 50 is fixed to the housing 60.

  The circuit holder 50 in the first embodiment is configured by a cap-shaped insulating member (insulating cap member). The circuit holder 50 is integrally formed by resin molding using, for example, an insulating resin material such as polybutylene terephthalate (PBT).

(Casing)
As illustrated in FIG. 3, the housing 60 is configured to surround the drive circuit 40, the support base 30, and the circuit holder 50, and a predetermined space area exists inside the housing 60. The casing 60 in the first embodiment is an outer member (outer casing), and the outer surface of the casing 60 is exposed outside the lamp (in the atmosphere). 60 is integrally molded by resin molding using an insulating resin material such as PBT.

(Base)
The base 70 is a power receiving unit that receives power for causing the LED module 20 (LED 22) to emit light from the outside of the lamp. The base 70 is attached to a socket of a lighting fixture, for example. Thereby, the base 70 can receive electric power from the socket of the lighting fixture when the light bulb shaped lamp 1 is turned on. The base 70 is supplied with, for example, commercial AC power. The base 70 in the first embodiment receives AC power through two contacts, and the power received by the base 70 is input to the power input unit of the drive circuit 40 via a pair of input-side lead wires.

  The base 70 has a bottomed cylindrical shape made of metal, and may be constituted by, for example, a shell portion whose outer peripheral surface is a male screw and an eyelet portion attached to the shell portion via an insulating portion. it can. On the outer peripheral surface of the base 70, a screwing portion for screwing into the socket of the lighting fixture is formed. Further, on the inner peripheral surface of the base 70, a screwing portion for screwing with the screwing portion of the housing 60 is formed.

  The type of the base 70 is not particularly limited, but in the first embodiment, a screwed-type Edison type (E type) base is used. For example, E27 type etc. are mentioned as a nozzle | cap | die 70. FIG.

(Circuit configuration of the drive circuit)
Next, the circuit configuration of the drive circuit 40 according to the first embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating a circuit configuration of the drive circuit 40 according to the first embodiment.

  As shown in FIG. 4, the drive circuit 40 according to the first embodiment is an LED drive circuit (LED lighting circuit) for lighting the LED 22, and includes a first rectifier circuit 110, an inverter 120, and an inverter. A control circuit 130, a second rectifier circuit 140, and a malfunction prevention circuit 150 are provided. The figure also shows an AC power source that supplies commercial power to the drive circuit 40, a switch circuit 160, and an LED 22 that is supplied with DC power from the drive circuit 40.

  The drive circuit 40 has input terminals P1 and P2 for receiving an AC voltage input. The input terminals P <b> 1 and P <b> 2 are connected to the AC power source and are connected to the input terminal of the first rectifier circuit 110. For example, a commercial AC power supply is connected to the input terminals P1 and P2 of the drive circuit 40 through a wall switch. The commercial AC power source is a commercial 100V AC power source, that is, a home AC power source. The input terminals P1 and P2 are, for example, the cap 70 of the light bulb shaped lamp 1 shown in FIGS. 2 and 3, which is attached to a socket to which AC power is supplied.

  The drive circuit 40 has output terminals P3 and P4 for outputting a DC voltage. The output terminals P3 and P4 are connected to the LED 22 and to the output terminal of the second rectifier circuit 140. The output terminal P3 on the high potential side is connected to the anode side of the LED 22, and the output terminal P4 on the low potential side is connected to the cathode side of the LED 22. The LED 22 is lit by a DC voltage supplied from the drive circuit 40. In the first embodiment, a capacitor C9 and a resistor R13 are connected in parallel with the LED 22.

  Hereinafter, each component of the drive circuit 40 according to the first embodiment will be described in detail.

  First, the first rectifier circuit 110 will be described. The first rectifier circuit 110 (DB1) is a bridge-type full-wave rectifier circuit composed of four diodes, and two terminals on the input side are connected to an AC power source via input terminals P1 and P2, and output side Are connected to the smoothing capacitors C1 and C2. The smoothing capacitors C1 and C2 are provided to stabilize the output voltage of the first rectifier circuit 110, and are, for example, electrolytic capacitors. Although an example in which two smoothing capacitors C1 and C2 are used is shown here, one smoothing capacitor may be connected between two output-side terminals of the first rectifier circuit 110. .

  A current fuse element FS (15Ω) is inserted in series in the wiring connecting the AC power supply and the first rectifier circuit 110. In addition, a switch circuit 160 is inserted in series in a wiring connecting the AC power source and the first rectifier circuit 110. In addition, a noise filter NF (1 mH) for removing switching noise is inserted in the wiring connecting the negative electrode of the voltage output terminal of the first rectifier circuit 110 and the inverter control circuit 130.

  The first rectifier circuit 110 receives an AC voltage (for example, 50 or 60 Hz) from a commercial AC power source through a wall switch, for example, and full-wave rectifies the AC voltage to output a DC voltage. The DC voltage output from the first rectifier circuit 110 is smoothed by the smoothing capacitors C1 and C2 to become the DC input voltage Vin. The input voltage Vin is supplied to the inverter 120 and the inverter control circuit 130.

  The switch circuit 160 includes a switch S1 and an auxiliary LED 23.

  The switch S1 is a switch that is turned on when the wall switch is turned on and turned off when the wall switch is turned off. That is, the switch S1 is a switch that is turned on when the light bulb lamp 1 is turned on and turned off when the light bulb is turned off. Specifically, the switch S1 is, for example, a semiconductor switch.

  The auxiliary LED 23 is an LED provided in the wall switch portion. The auxiliary LED 23 does not emit light when the light bulb shaped lamp 1 is turned on because the switch S1 is turned on, but emits light when the light bulb shaped lamp 1 is turned off because the switch S1 is turned off.

  That is, the switch circuit 160 (the switch S1 and the auxiliary LED 23) is a so-called firefly switch that emits light to illuminate the vicinity of the wall switch when the light bulb shaped lamp 1 is turned off and the room is dark. In FIG. 4, the circuit diagram of the switch circuit 160 is schematically shown and is not necessarily shown accurately.

  Next, the inverter 120 will be described. The inverter 120 (INV) outputs electric power for driving the LED 22. In Embodiment 1, inverter 120 converts a DC voltage into an AC voltage. For example, the inverter 120 converts a DC voltage into an AC voltage of several tens of kHz.

  The inverter 120 includes a switching element Q1, a switching element Q2 connected in series to the switching element Q1, a current transformer CT, an inductor L1, capacitors C5, C6 and C8, and resistors R5, R6, R7 and R8. And diodes D2 and D3.

  In the first embodiment, the inverter 120 is a half-bridge self-excited inverter, and a series circuit including a switching element Q1 and a switching element Q2 that alternately perform a switching operation is connected to the first rectifier circuit 110. It is configured. In the first embodiment, switching element Q1 and switching element Q2 are bipolar transistors. In the first embodiment, the self-excited inverter is an inverter to which feedback is applied using a current transformer and a plurality of switching elements.

  The collector of the switching element Q1 is connected to the positive electrode of the DC voltage output terminal of the first rectifier circuit 110 and the capacitor C5. The emitter of the switching element Q1 is connected to the collector of the switching element Q2 and the coil of the current transformer CT via a resistor R5. The base of the switching element Q1 is connected to the coil of the current transformer CT via a resistor R7.

  The collector of the switching element Q2 is connected to the emitter of the switching element Q1 and the coil of the current transformer CT via a resistor R5. The emitter of the switching element Q2 is connected to the negative electrode of the DC voltage output terminal of the first rectifier circuit 110, the coil of the current transformer CT, and the capacitors C6 and C8 via the resistor R6. The base of the switching element Q2 is connected to the coil of the current transformer CT via the resistor R8.

  The current transformer CT (driving transformer) is constituted by a winding coil including a primary winding (input winding) and a secondary winding (output winding).

  The inductor L1 is a choke inductor, and has one end connected to the output side of the current transformer CT and the other end connected to the input side of the second rectifier circuit 140. Capacitor C5 has one end connected to the positive electrode of the DC voltage output terminal of first rectifier circuit 110 and the other end connected to the input side of second rectifier circuit 140. One end of the capacitor C6 is connected to the negative electrode of the DC voltage output end of the first rectifier circuit 110, and the other end is connected to the input side of the second rectifier circuit 140. One end of the capacitor C8 is connected to the negative electrode of the DC voltage output end of the first rectifier circuit 110, and the other end is connected to the other end of the inductor L1.

  The diode D2 has a cathode connected to the positive electrode of the DC voltage output terminal of the first rectifier circuit 110 and the capacitor C5, and an anode connected to the coil of the current transformer CT and the emitter of the switching element Q1 via the resistor R5. ing. The diode D3 has a cathode connected to the coil of the current transformer CT, an anode connected to the negative electrode of the DC voltage output terminal of the first rectifier circuit 110, the emitter of the switching element Q2 via the resistor R6, and the coil of the current transformer CT. And capacitors C6 and C8.

  In the inverter 120 configured as described above, a predetermined input voltage Vin is applied between both ends of the series circuit of the switching element Q1 and the switching element Q2 (to the input terminal of the inverter 120), and start-up control is performed from the inverter control circuit 130. It operates by supplying a signal (trigger signal). Specifically, the switching element Q1 and the switching element Q2 are alternately turned on and off by self-excited oscillation based on the induction of the current transformer CT, whereby the AC secondary voltage due to the series resonance between the inductor L1 and the capacitor C8 is increased. This voltage is induced and supplied to the second rectifier circuit 140.

  Next, the inverter control circuit 130 for starting the inverter 120 will be described. The inverter control circuit 130 (TRG) is configured to start the inverter 120. In Embodiment 1, inverter control circuit 130 starts operation of inverter 120 and then stops. The inverter 120 started to operate by the inverter control circuit 130 is maintained by the current transformer CT and each element constituting the inverter 120. Specifically, the current transformer CT, which is a magnetic saturation current transformer, controls the switching element Q1 and the switching element Q2 by being magnetically saturated according to on / off of the switching element Q1 and the switching element Q2. Therefore, the inverter 120 maintains the operation after the operation is started by the inverter control circuit 130.

  The inverter control circuit 130 includes a resistor R2, a capacitor C3 connected in series to the resistor R2, and a trigger diode TD connected to a connection point between the resistor R2 and the capacitor C3.

  The resistor R2 is connected to the positive electrode of the DC voltage output terminal of the first rectifier circuit 110, and is connected to the negative electrode of the DC voltage output terminal of the first rectifier circuit 110 via the capacitor C3. The capacitor C3 is a capacitor for controlling the conduction of the trigger diode TD, and the high potential side is connected to the resistor R2, and the low potential side is connected to the negative electrode of the DC voltage output terminal of the first rectifier circuit 110. . Hereinafter, the positive terminal of the DC voltage output terminal of the first rectifier circuit 110 is referred to as a positive output terminal of the first rectifier circuit 110, and the negative terminal of the DC voltage output terminal of the first rectifier circuit 110 is referred to as a first terminal. May be described as a negative output terminal of the rectifier circuit 110.

  The trigger diode TD is a trigger element, which is turned on when a voltage exceeding a specified voltage (operating voltage, breakover voltage) is applied, and discharges the charge of the capacitor C3 to the base of the switching element Q2 to shorten the voltage. The time switch element Q2 is turned on. In the first embodiment, the trigger diode TD breaks over by the voltage value held in the capacitor C3 and becomes conductive. The trigger diode TD is connected to the base of the switching element Q2, which is a control terminal of the inverter 120, and the operation of the inverter 120 is started when the trigger diode TD is turned on.

  That is, the current starts to flow through the inverter 120 only when the switching element Q2 is turned on by the inverter control circuit 130. A voltage is induced in the secondary coil of the current transformer CT by the load current that flows when the switching element Q2 is turned on, so that the switching element Q2 is kept on and the switching element Q1 is kept off.

  When the switching element Q2 is kept on, the noise filter NF, the capacitor C5, the second rectifier circuit 140, the LED 22, the inductor L1, and the current transformer CT are connected from the high potential side DC voltage output terminal of the first rectifier circuit 110. A current limited by the inductor L1 flows through the primary winding, the switching element Q2, and the resistor R6. This current magnetically saturates the core of the current transformer CT, and its secondary winding output voltage becomes zero. Therefore, the charge accumulated between the base and the emitter of the switching element Q2 is discharged. When the accumulated charge is exhausted, the switching element Q2 is turned off.

  When the switching element Q2 is turned off, the energy stored in the inductor L1 due to the current flowing in the inductor L1 is discharged to C5 and the LED 22 via the diode D2. Due to the discharge current, the magnetic saturation of the current transformer CT is released, and a voltage that makes the base potential of the switching element Q1 positive is generated in the secondary winding on the switching element Q1 side of the current transformer CT. A voltage is generated in the secondary winding on the switching element Q2 side to make the base of the switching element Q2 negative.

  When the energy stored in the inductor L1 is exhausted, the current flowing through the diode D2 disappears and the energy stored in the capacitors C5 and C6 is discharged through the switching element Q1. Further, from the high potential side DC voltage output terminal of the first rectifier circuit 110, the noise filter NF, the switching element Q1, the current transformer CT, the inductor L1, the capacitor C8, the LED 22 and the capacitor C6 A current flows through the low potential side DC voltage output terminal of one rectifier circuit 110.

  With this current, energy is accumulated in the inductor L1 and the capacitor C8, and a voltage is generated in the secondary winding of the current transformer CT to keep the switching element Q1 on and keep the switching element Q2 off.

  Thereafter, when magnetic saturation of the current transformer CT occurs, the accumulated charge of the switching element Q1 is discharged. When this discharge ends, switching element Q1 is turned off. The stored energy of the inductor L1 at the moment when the switching element Q1 is turned off is discharged through the current transformer CT, the diode D3, the capacitor C8, the LED 22, and the capacitors C6 and C5, and the magnetic saturation of the current transformer CT is reduced. The voltage is generated to make the base of the switching element Q2 positive and the base of the switching element Q1 negative. When the stored energy in the inductor L1 is exhausted, the switching element Q1 and the switching element Q2 are alternately turned on and off alternately as described above, and the series resonance between the inductor L1 and the capacitor C8 is generated to maintain the oscillation. Steady operation.

  As the trigger diode TD, for example, a diac having a voltage breakover of 28 to 36 V can be used.

  As described above, the inverter control circuit 130 is a circuit for starting the inverter 120, which adjusts the voltage applied to both ends of the capacitor C3 by the resistor R2, and the trigger diode that breaks over by the voltage value of the capacitor C3. TD. Then, when a trigger signal is input from the inverter control circuit 130 to the inverter 120, self-oscillation of the inverter 120 starts.

  Furthermore, in the first embodiment, the inverter control circuit 130 includes a diode D1 connected in parallel with the resistor R2. The diode D1 is a rectifying diode, and the anode side of the diode D1 is connected to the connection point between the resistor R2 and the capacitor C3 and the trigger diode TD. The cathode side of the diode D1 is connected to a connection point between the switching element Q1 (emitter) and the switching element Q2 (collector) in the inverter 120 and a capacitor C4. The capacitor C4 has a high potential side connected to the positive electrode of the DC voltage output terminal of the first rectifier circuit 110 and the collector of the switching element Q1, and a low potential side connected to the cathode of the diode D1. Capacitor C4 is a snubber capacitor, and is used as appropriate to slow down the voltage change speed of switching elements Q1 and Q2 and reduce switching loss.

  Next, the second rectifier circuit 140 will be described. Similarly to the first rectifier circuit 110, the second rectifier circuit 140 (DB2) is a bridge-type full-wave rectifier circuit composed of four diodes, and two terminals on the input side are the output side of the inverter 120. Of the two output terminals, the high potential side is connected to the anode side of the LED 22 via the output terminal P3, and the low potential side is connected to the cathode side of the LED 22 via the output terminal P4. Yes.

  The second rectifier circuit 140 receives the AC voltage from the inverter 120, outputs a voltage obtained by full-wave rectification of the AC voltage, and supplies the voltage to the LED 22.

  Note that the second rectifier circuit 140 can be configured, for example, by combining two semiconductor components in which two Schottky diodes are connected in series. Further, the second rectifier circuit 140 may have a stack configuration in which a secondary winding divided into two is provided in the inductor L1, and one is provided at the output thereof.

  Next, the malfunction prevention circuit 150 that is a characteristic configuration of the drive circuit 40 according to the first embodiment will be described.

  The malfunction prevention circuit 150 is connected between the positive output terminal and the negative output terminal of the first rectifier circuit 110 in parallel with the inverter control circuit 130.

  The malfunction prevention circuit 150 includes resistors R3, R9, R10, R11, and R12, a switching element Q3 (second switching element), and a switching element Q4 (first switching element).

  The switching element Q3 is a bipolar transistor. The emitter of the switching element Q3 is connected to the negative output terminal of the first rectifier circuit 110. The base of the switching element Q3 is connected to the other end of the resistor R10 and the collector of the switching element Q4. The collector of the switching element Q3 is connected to the other end of the resistor R3.

  One end of the resistor R3 is connected to the positive output terminal of the first rectifier circuit 110, and the other end of the resistor R3 is connected to the collector of the switching element Q3.

  Resistor R3 and switching element Q3 constitute a second current path. In other words, the second current path has a resistor R3, one end connected to the positive output terminal of the first rectifier circuit 110, and the other end connected to the negative output terminal of the first rectifier circuit 110. Is done. Here, the second current path is a current path from the positive output terminal of the first rectifier circuit 110 to the negative output terminal.

  The switching element Q4 is a bipolar transistor. The emitter of the switching element Q4 is connected to the negative output terminal of the first rectifier circuit 110. The base of the switching element Q4 is connected to a connection point between the resistors R11 and R12 (the other end of the resistor R11 and one end of the resistor R12). The collector of the switching element Q4 is connected to the other end of the resistor R10 and the base of the switching element Q3.

  One end of the resistor R9 is connected to the positive output terminal of the first rectifier circuit 110, and the other end of the resistor R9 is connected to one end of the resistor R10 and one end of the resistor R11.

  One end of the resistor R10 is connected to the other end of the resistor R9, and the other end of the resistor R10 is connected to the base of the switching element Q3 and the collector of the switching element Q4.

  One end of the resistor R11 is connected to a connection point between the resistor R9 and the resistor R10 (the other end of the resistor R9 and one end of the resistor R10), and the other end of the resistor R11 is connected to one end of the resistor R12 and switching. Connected to the base of element Q4.

  One end of the resistor R12 is connected to the other end of the resistor R11 and the base of the switching element Q4, and the other end of the resistor R12 is connected to the negative output terminal of the first rectifier circuit 110.

  Resistors R9 and R10 and switching element Q4 form a first current path. In other words, the first current path includes resistors R9 and R10 and the switching element Q4, one end of which is connected to the positive output terminal of the first rectifier circuit 110, and the other end of the first rectifier circuit. 110 is connected to the negative output terminal. That is, the first current path is a current path from the positive output terminal of the first rectifier circuit 110 to the negative output terminal, and is a current path different from the second current path.

  In the first embodiment, the resistance value of the resistor R2 is 1 MΩ, and the resistance value of the resistor R3 is 36 kΩ. In the first embodiment, the resistance value of the resistor R9 is 470 kΩ, the resistance value of the resistor R10 is 560 kΩ, the resistance value of the resistor R11 is 820 kΩ, and the resistance value of the resistor R12. Is 15 kΩ.

  The drive circuit 40 according to the first embodiment is configured as described above.

  Note that the first rectifier circuit 110 corresponds to a DC power supply circuit. The inverter control circuit 130 corresponds to a control circuit. The switching element Q4 corresponds to a first switching element, and the switching element Q3 corresponds to a second switching element.

  The resistor R3 corresponds to a second resistor, and the resistor R9 corresponds to a first resistor. The resistor R10 corresponds to a third resistor, the resistor R11 corresponds to a fourth resistor, and the resistor R12 corresponds to a fifth resistor.

  In the circuit diagram of FIG. 4, one LED 22 which is an example of a light emitting element is turned on by the drive circuit 40, but a plurality of LEDs 22 may be provided as the light emitting element. In this case, the plurality of LEDs 22 may be connected in series, may be connected in parallel, or the plurality of LEDs 22 may be configured by combining series connection and parallel connection.

(Circuit operation)
Next, the operation of the drive circuit 40 according to the first embodiment will be described.

  For example, when the user turns on the wall switch to turn on the LED 22, AC power is supplied to the input terminals P <b> 1 and P <b> 2, and the DC input voltage Vin smoothed by the first rectifier circuit 110 is generated. The input voltage Vin is supplied between the input terminals of the inverter 120 and between the input terminals of the inverter control circuit 130. At this time, the switch S1 is in the ON state.

  As a result, the inverter control circuit 130 and the inverter 120 operate. That is, when the input voltage Vin is supplied to the inverter control circuit 130, the capacitor C3 of the inverter control circuit 130 is charged, and the trigger diode TD breaks over. As a result, the trigger diode TD becomes conductive, a trigger signal (trigger pulse) is supplied to the base of the switching element Q2 of the inverter 120, and the switching element Q2 is turned on.

  When the switching element Q2 is turned on by the trigger signal, the inverter 120 is activated, and the switching element Q1 and the switching element Q2 are alternately turned on and off by self-excited oscillation based on the induction of the current transformer CT, and an AC secondary voltage is induced. The As a result, an AC voltage in which the secondary voltage is increased by the series resonance of the inductor L1 and the capacitor C8 is supplied to the second rectifier circuit 140. Then, the AC voltage is full-wave rectified by the second rectifier circuit 140, and a predetermined DC voltage (forward voltage VF) is supplied to the LED 22 via the output terminals P3 and P4. Thereby, LED22 lights with desired brightness.

  Next, when the user turns off the wall switch in order to turn off the LED 22, the supply of AC power to the input terminals P1 and P2 is stopped, and thus the LED 22 is turned off. At this time, the switch S1 is in an OFF state, and the auxiliary LED 23 provided on the wall switch emits light to illuminate the vicinity of the wall switch.

(Operation of malfunction prevention circuit)
Next, the operation of the malfunction prevention circuit 150 which is a characteristic configuration of the drive circuit 40 according to the first embodiment will be described.

  In the following description, “the resistance value of the malfunction prevention circuit 150” means that when only the malfunction prevention circuit 150 is taken out from the drive circuit 40, the malfunction prevention circuit 150 of the first rectifier circuit 110. It means the resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal of the first rectifier circuit 110.

  Further, in the following description, “the resistance value of the inverter control circuit 130” means the positive output of the first rectifier circuit 110 of the inverter control circuit 130 when only the inverter control circuit 130 is taken out from the drive circuit 40. It means the resistance value (resistance component) from the end connected to the terminal to the end connected to the negative output terminal of the first rectifier circuit 110. That is, in the first embodiment, the resistance value of the inverter control circuit 130 is 1 MΩ which is the resistance value of the resistor R2.

  First, an operation when the LED 22 is turned on will be described.

  FIG. 5 is a diagram for explaining the operation of the malfunction prevention circuit 150 when the LED 22 is turned on.

  As described above, when the LED 22 is turned on, the first rectifier circuit 110 supplies the input voltage Vin between the both ends of the malfunction prevention circuit 150 and the input terminal of the inverter control circuit 130. In the first embodiment, the input voltage Vin is 140V.

  At this time, as shown in FIG. 5A, the voltage between the emitter and base of the switching element Q4, that is, the voltage at both ends of the resistor R12, is 140V as resistors R9 (470 kΩ), R11 (820 kΩ), And R12 (15 kΩ), the voltage is about 1.6V.

  As a result, the voltage between the emitter and the base of the switching element Q4 exceeds the threshold voltage 0.6V, so that the switching element Q4 is turned on. On the other hand, since the voltage between the emitter and the base of the switching element Q3 is almost 0 V, the switching element Q3 is in the OFF state.

  Therefore, as shown in FIG. 5B, when the LED 22 is lit, a current flows mainly through the first current path (resistor R9, resistor R10, and switching element Q4) and the resistor R2. If the state of the malfunction prevention circuit 150 at this time is the first resistance state, the resistance value of the malfunction prevention circuit 150 in the first resistance state is about 805 kΩ. This is because, in the case of FIG. 5B, the resistance value of the malfunction prevention circuit 150 is the resistance of the combined resistor in which the resistor R9 is connected in series with the resistor R10 and the resistors R11 and R12 in parallel. Because it means a value.

  On the other hand, since the resistance value of the resistor R2 is 1 MΩ, a sufficient current flows through the resistor R2 and the capacitor C3 is charged. Therefore, the trigger diode TD breaks over and the inverter 120 starts oscillating.

  As described above, the malfunction prevention circuit 150 does not hinder the lighting of the LED 22. That is, the malfunction prevention circuit 150 enters the first resistance state when the input voltage Vin is applied, and operates the inverter control circuit 130. As a result, the inverter 120 starts operating, and the LED 22 emits light.

  In the example of FIG. 5, the resistance value (about 805 kΩ) when the malfunction prevention circuit 150 is in the first resistance state is smaller than the resistance value (1 MΩ) of the inverter control circuit 130.

  However, the resistance value when the malfunction prevention circuit 150 is in the first resistance state is preferably larger than the resistance value of the inverter control circuit 130. This is because power consumption generated in the malfunction prevention circuit 150 can be reduced.

  Next, the operation when the LED 22 is turned off will be described.

  FIG. 6 is a diagram for explaining the operation of the malfunction prevention circuit 150 when the LED 22 is turned off.

  Hereinafter, a case where the above-described switch S1 is in an OFF state, a leakage current flows from the switch S1 to the first rectifier circuit 110, and the output of the first rectifier circuit 110 is 30 V, which is lower than 140 V during normal lighting. To do.

  As shown in FIG. 6A, the DC voltage 30V due to the influence of the leakage current is divided by resistors R9, R11, and R12. The voltage between the emitter and base of the switching element Q4, that is, the voltage across the resistor R12 is about 0.34V, and does not exceed the threshold voltage 0.6V of the switching element Q4, so that the switching element Q4 is turned off.

  On the other hand, as shown in FIG. 6A, since the current flows into the base of the switching element Q3 via the resistor R10, the switching element Q3 is turned on.

  Here, the resistance value of the resistor R3 is 36 kΩ, which is a very small value equal to or less than 1/20 of the resistance value 1 MΩ of the resistor R2. Therefore, as shown in FIG. 6B, when the LED 22 is lit, a current flows mainly through the second current path (resistor R3 and switching element Q3).

  If the state of the malfunction prevention circuit 150 at this time is the second resistance state, the resistance value of the malfunction prevention circuit 150 in the second resistance state is connected to the resistors R9, R11, and R12 in series. Since it is the resistance value of the combined resistance in which R3 is connected in parallel, it is about 35 kΩ, which is a very small value of 1/20 or less of the resistance value of the inverter control circuit 130 (resistance value of the resistor R2: 1 MΩ).

  The resistance value of the malfunction prevention circuit 150 in the second resistance state is smaller than the resistance value (about 805 kΩ) of the malfunction prevention circuit 150 in the first resistance state, and the malfunction prevention circuit in the first resistance state. It is less than 1/20 of the resistance value of 150.

  Therefore, almost no current flows through the resistor R2 (inverter control circuit 130), and no charge is accumulated in the capacitor C3. Therefore, the inverter 120 is maintained in a stopped state without oscillating. Therefore, the LED 22 is not lit.

  The resistance value of the resistor R3 is preferably smaller than the resistance value of the resistor R2, but even if it is larger than the resistance value of the resistor R2, the current flowing through the capacitor C3 is suppressed and the inverter control circuit is activated. Don't let it happen.

  The resistor R11 and the resistor R12 monitor the voltage supplied from the first rectifier circuit 110, and control whether to conduct the first current path or to conduct the second current path. It can be said that it constitutes a control current path. Specifically, the control current path performs switching control of whether the first current path is conducted or the second current path is conducted according to the voltage applied to both ends of the resistor R12. Yes.

  As described above, the malfunction prevention circuit 150 prevents the LED 22 from being turned on due to malfunction when the LED 22 is turned off. In other words, the malfunction prevention circuit 150 has a second resistance value smaller than that of the first resistance state when a predetermined voltage (30 V in the above example) smaller than the input voltage Vin (140 V) is applied. Resistance state. Further, the malfunction prevention circuit 150 draws at least a part of the current supplied from the first rectifier circuit 110 to the inverter control circuit 130 and does not operate the inverter control circuit 130 (stops the operation).

  In the first embodiment, the threshold voltage for causing the malfunction prevention circuit 150 to conduct the second current path is set to about 50V. In other words, when the voltage supplied from the first rectifier circuit 110 is about 50V or more, the voltage applied between the emitter and base of the switching element Q4 becomes 0.6V or more, and the switching element Q4 is in the ON state. Become. In other words, when the voltage supplied from the first rectifier circuit 110 is about 50 V or more, the malfunction prevention circuit 150 makes the second current path non-conductive and makes the first current path conductive to make the first current path non-conductive. 1 resistance state.

  When the voltage supplied from the first rectifier circuit 110 is less than about 50V, the voltage applied between the emitter and base of the switching element Q4 becomes less than 0.6V, and the switching element Q3 is turned on. . That is, when the voltage supplied from the first rectifier circuit 110 is less than about 50 V (when the voltage is a predetermined voltage lower than the input voltage), the malfunction prevention circuit 150 conducts the second current path to make the first current path conductive. 2 resistance state.

  The threshold voltage is not limited to 50V. The threshold voltage is desirably set according to the configuration of the inverter control circuit 130 and the characteristics of the first rectifier circuit (DC power supply circuit). The threshold voltage is preferably set in consideration of the flow rate of leakage current and minute current due to the switch circuit 160 and the like, the fluctuation state of the input voltage Vin during normal lighting, and the like.

  As described above, according to the malfunction prevention circuit 150, malfunction when the illumination light source is turned off can be prevented, and the illumination light source can be reliably turned off.

  In the malfunction prevention circuit 150 according to the first embodiment, the second current path includes the resistor R3. By adjusting the value of the resistor R3, the switch circuit 160 of the switch circuit 160 is turned off when the light bulb shaped lamp 1 is turned off. The amount of current flowing through the auxiliary LED 23 can be adjusted.

  The malfunction prevention circuit 150 according to Embodiment 1 is an example of the malfunction prevention circuit of the present invention, and the malfunction prevention circuit of the present invention is not limited to such a configuration. The malfunction prevention circuit of the present invention is in a low resistance state when an input voltage less than a predetermined value is supplied to the control circuit (inverter control circuit 130) when the light is turned off, and is controlled from the DC power supply circuit (first rectifier circuit 110). Other circuit configurations may be used as long as at least part of the current supplied to the circuit is drawn to stop the control circuit.

  Further, the DC power supply circuit (first rectifier circuit 110) and the control circuit (inverter control circuit 130) to which the malfunction prevention circuit is applied are not limited to the configuration as in the first embodiment.

  For example, the DC power supply circuit is not limited to the configuration of the first rectifier circuit 110, and may be an AC-DC converter IC or the like. The DC power supply circuit may have other circuit configurations, for example, a configuration including an AC power supply.

  Further, when the control circuit has a circuit configuration as in the first embodiment, an IC including the inverter control circuit 130 and the inverter 120 may be used. That is, the control circuit may include the inverter control circuit 130 and the inverter 120. The control circuit may have other circuit configurations.

(Embodiment 2)
In the first embodiment, a half-bridge self-excited inverter is used as an example of the inverter 120. However, the present invention is not limited to this. For example, an inverter having a configuration other than the half bridge type may be used.

  In the second embodiment, an example of a drive circuit using a separately excited inverter will be described.

  FIG. 7 is a diagram illustrating a circuit configuration of the drive circuit according to the second embodiment.

  The drive circuit 40b shown in FIG. 7 has the same basic configuration as that of the drive circuit 40 according to the first embodiment. In FIG. 7, the same components as those shown in FIG. The detailed explanation is omitted.

  The drive circuit 40b shown in FIG. 7 is different from the drive circuit 40 shown in FIG. 4 in the configuration of the inverter.

  The inverter 120b of the drive circuit 40b has one switching element Q5, one diode D4, and an inductor L2.

  The switching element Q5 is a bipolar transistor. The emitter of the switching element Q5 is connected to one end of the inductor L2 and to the anode side of the diode D4. Furthermore, the emitter of the switching element Q5 is connected to the cathode side of the diode D1 of the inverter control circuit 130. The collector of the fifth switching element Q5 is connected to the negative output terminal of the first rectifier circuit 110. The base of the switching element Q5 is connected to the trigger diode TD of the inverter control circuit 130.

  The cathode side of the diode D4 is connected to the positive output terminal of the first rectifier circuit 110. The anode side of the diode D4 is connected to a connection point between the inductor L2 and the switching element Q5.

  The inductor L2 has one end connected to the connection point between the switching element Q5 and the diode D4, and the other end connected to the input side of the second rectifier circuit 140.

  When the input voltage Vin output from the first rectifier circuit 110 is applied, the inverter 120b configured as described above operates based on the activation control signal from the inverter control circuit 130. As a result, an AC voltage is supplied from the inverter 120b to the second rectifier circuit 140.

  Next, the operation of the drive circuit 40b will be described.

  For example, when the user turns on the wall switch to turn on the LED 22, the input voltage Vin (140V) having a predetermined value is supplied and the inverter control circuit 130 and the inverter 120b operate as in the first embodiment.

  That is, the capacitor C3 of the inverter control circuit 130 is charged, the trigger diode TD is turned on, the trigger signal (trigger pulse) is supplied to the base of the switching element Q5 of the inverter 120b, and the switching element Q5 is turned on.

  When the switching element Q5 is turned on by the trigger signal, the input voltage Vin causes a current to flow in the order of the second rectifier circuit 140, the LED 22, the second rectifier circuit 140, the inductor L2, and the switching element Q5, and the LED 22 is lit. .

  Then, the charge of the capacitor C3 is released through the diode D1 and the base of the switching element Q5, and the switching element Q5 and the trigger diode TD are turned off. Then, the energy stored in the inductor L2 returns to the smoothing capacitor C1 via the diode D4 and starts charging the capacitor C3. When the above feedback current has completely flowed, the trigger diode TD is turned on again, and the switching element Q5 is turned on. A resistor may be added between the capacitor C3 and the diode D1 in order to change the ON time of the switching element Q5.

  Next, when the user turns off the wall switch to turn off the LED 22, the LED 22 is turned off.

  For such an inverter 120b as well, by setting the threshold voltage of the malfunction prevention circuit 150 appropriately, malfunction during turn-off can be prevented.

(Embodiment 3)
Further, the present invention can be realized not only as a light bulb shaped lamp as in Embodiments 1 and 2, but also as an illumination device including a light bulb shaped lamp. Hereinafter, in Embodiment 3, such an illumination device will be described with reference to FIG. FIG. 8 is a schematic cross-sectional view of the illumination device according to the third embodiment.

  As shown in FIG. 8, the lighting device 2 according to the third embodiment is used by being mounted on an indoor ceiling, for example, and the light bulb shaped lamp 1 according to the first or second embodiment, the lighting fixture 3, and the like. Is provided.

  The lighting device 3 has a function of turning off and lighting the light bulb shaped lamp 1, and includes a device main body 4 attached to the ceiling and a translucent lamp cover 5 covering the light bulb shaped lamp 1.

  The instrument body 4 has a socket 4a. A base 70 of the light bulb shaped lamp 1 is screwed into the socket 4a. Electric power is supplied to the light bulb shaped lamp 1 through the socket 4a.

  Note that the lighting fixture is not limited to the one shown in FIG. 8, and a ceiling-embedded lighting fixture that is embedded in the ceiling, such as a downlight or a spotlight, can also be used.

(Other)
As described above, the light bulb shaped lamp and the lighting device according to the present embodiment have been described based on the embodiments. However, the present invention is not limited to these embodiments.

  In the above embodiment, the SMD type LED element packaged as the LED 22 is used. However, the present invention is not limited to this. For example, a COB (Chip On Board) structure LED module 20 configured by directly mounting a plurality of LEDs 22 (bare chips) on the substrate 21 using a bare chip as the LED 22 may be used. In this case, the plurality of bare chips are collectively sealed with the phosphor-containing resin.

  In the above embodiment, the LED module 20 is configured to emit white light by the blue LED chip and the yellow phosphor. However, the present invention is not limited to this. For example, in order to improve color rendering properties, a red phosphor or a green phosphor may be further mixed in addition to the yellow phosphor. Moreover, it is also possible to use a phosphor-containing resin containing a red phosphor and a green phosphor without using a yellow phosphor, and to emit white light by combining this with a blue LED chip. it can.

  Moreover, in said embodiment, you may use the LED chip which light-emits colors other than blue as an LED chip. For example, when an ultraviolet light emitting LED chip is used, a combination of phosphor particles that emit light in three primary colors (red, green, and blue) can be used as the phosphor particles. Furthermore, a wavelength conversion material other than the phosphor particles may be used. For example, the wavelength conversion material absorbs light of a certain wavelength such as a semiconductor, a metal complex, an organic dye, or a pigment, and has a wavelength different from the absorbed light. A material containing a substance that emits light may be used.

  In the above embodiment, the LED is exemplified as the light emitting element. However, the semiconductor light emitting element such as a semiconductor laser or the other solid light emitting element such as an EL element such as an organic EL (Electro Luminescence) or an inorganic EL is used. Also good.

  In the above embodiment, the present invention is realized as a light bulb shaped lamp and an illumination device including the same. However, the present invention can also be realized as other illumination light sources and illumination devices.

  For example, the present invention can be realized as an LED unit having a flat thin structure, which is an illumination light source used in an LED illumination device such as a downlight or a spotlight. The present invention can also be realized as a straight tube LED lamp or an annular LED lamp which is a light source for illumination.

  The circuit configuration shown in the circuit diagram is an example, and the present invention is not limited to the circuit configuration. That is, like the above circuit configuration, a circuit that can realize a characteristic function of the present invention is also included in the present invention. For example, the present invention includes a device in which a device such as a switching device (transistor), a resistor, or a capacitor is connected in series or in parallel to a certain device within a range in which a function similar to the above circuit configuration can be realized. It is. In other words, the term “connected” in the above embodiment is not limited to the case where two terminals (nodes) are directly connected, and the two terminals ( Node) is connected through an element.

  In addition, the present invention can be realized by various combinations conceived by those skilled in the art for each embodiment, or by arbitrarily combining the components and functions in each embodiment without departing from the spirit of the present invention. This form is also included in the present invention.

1 Light bulb shaped lamp (light source for illumination)
DESCRIPTION OF SYMBOLS 2 Illuminating device 3 Lighting fixture 4 Appliance main body 4a Socket 5 Lamp cover 10 Globe 20 LED module 21 Board | substrate 22 LED (light emitting element)
23 Auxiliary LED
DESCRIPTION OF SYMBOLS 30 Support stand 40, 40a, 40b Drive circuit 41 Circuit board 50 Circuit holder 60 Case 70 Base 110 1st rectifier circuit (DC power supply circuit)
120, 120b Inverter 130, 130a Inverter control circuit (control circuit)
140 Second rectifier circuit 150 Malfunction prevention circuit 160 Switch circuit CT Current transformer D1 to D4 Diode FS Current fuse element L1, L2 Inductor NF Noise filter P1, P2 Input terminal P3, P4 Output terminal Q1, Q2, Q5 Switching element Q3 Switching element (second switching element)
Q4 switching element (first switching element)
R1, R2, R4 to R8, R13 Resistor R3 Resistor (second resistor)
R9 resistor (first resistor)
R10 resistor (third resistor)
R11 resistor (fourth resistor)
R12 resistor (fifth resistor)
C1-C6, C8, C9 Capacitor TD Trigger diode

Claims (10)

A malfunction prevention circuit for preventing malfunction of a control circuit that operates when a predetermined current flows by applying an input voltage from a DC power supply circuit and emits a light emitting element,
Connected between a positive output terminal and a negative output terminal of the DC power supply circuit;
When the input voltage is applied, the first resistance state is entered, the control circuit is activated,
When a voltage smaller than the input voltage is applied, the second resistance state having a resistance value smaller than that of the first resistance state is set, and at least a part of the current supplied from the DC power supply circuit to the control circuit is obtained. A malfunction prevention circuit that does not operate the control circuit by pulling in. The malfunction prevention circuit is
A first current path having a first resistor and having one end connected to the positive output terminal and the other end connected to the negative output terminal;
A second current path having a second resistance whose resistance value is smaller than that of the first resistance, one end connected to the positive output terminal, and the other end connected to the negative output terminal. ,
When the input voltage is applied, the first current path is conducted to enter the first resistance state;
2. The malfunction prevention circuit according to claim 1, wherein, when a voltage smaller than the input voltage is applied, the second current path is turned on to enter the second resistance state. The first current path further includes a first switching element,
The second current path further includes a second switching element,
The malfunction prevention circuit is
When the input voltage is applied, the first switching element is turned on to conduct the first current path;
3. The malfunction prevention circuit according to claim 2, wherein, when a voltage smaller than the input voltage is applied, the second switching element is turned on to conduct the second current path. 4. The control circuit is connected between a positive output terminal and a negative output terminal of the DC power supply circuit,
The resistance value when the malfunction prevention circuit is in the second resistance state is the resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal of the control circuit. The malfunction prevention circuit of any one of Claims 1-3. The resistance value when the malfunction prevention circuit is in the second resistance state is the resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal of the control circuit. The malfunction prevention circuit according to claim 4, wherein the malfunction prevention circuit is equal to or less than 1/20. The control circuit is connected between a positive output terminal and a negative output terminal of the DC power supply circuit,
The resistance value when the malfunction prevention circuit is in the first resistance state is the resistance value from the end connected to the positive output terminal to the end connected to the negative output terminal of the control circuit. The malfunction prevention circuit according to any one of claims 1 to 5. The resistance value when the malfunction prevention circuit is in the second resistance state is 1/20 or less of the resistance value when the malfunction prevention circuit is in the first resistance state. The malfunction prevention circuit according to any one of 6. The first current path further includes a third resistor,
The malfunction prevention circuit further includes a fourth resistor and a fifth resistor,
One end of the first resistor is connected to the positive output terminal,
The other end of the first resistor is connected to one end of the third resistor and one end of the fourth resistor,
One end of the second resistor is connected to the positive output terminal,
The other end of the second resistor is connected to the collector of the second switching element,
The other end of the third resistor is connected to the collector of the first switching element and the base of the second switching element,
The other end of the fourth resistor is connected to the base of the first switching element and one end of the fifth resistor,
The malfunction prevention circuit according to claim 3, wherein an emitter of the first switching element, an emitter of the second switching element, and the other end of the fifth resistor are connected to the negative output terminal. A malfunction prevention circuit according to any one of claims 1 to 8,
The control circuit;
An illumination light source comprising the light emitting element. An illumination device comprising the illumination light source according to claim 9.

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