JP2005294061A - Led lighting device and illumination fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device and an illumination fixture wherein a light emitting diode is lit with a high efficiency, and resistors for setting current can be protected from over-current. <P>SOLUTION: The LED lighting device 1 is provided with the light emitting diode 3 and the resistor R1 which are connected to a direct-current power source 2 together with an inductor L1 in series, the direct-current power source 2, a switching means FET1 to switch the connection of the inductor L1, the light emitting diode 3, and the resistor R1, the diode D1 which is connected so that it forms a closed circuit together with the inductor L1, the light emitting diode 3, and the resistor R1 when the switching means FET1 is off, and a circuit breaking means 6 which is interposed in the series circuit of the direct-current power source 2, the switching element FET1, the inductor L1, the light emitting diode 3, and the resistance R1, and which breaks the series circuit when a current not less than a prescribed value is made to flow in this series circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an LED lighting device and a lighting fixture for lighting a light emitting diode.

2. Description of the Related Art An LED lighting device is known in which an inductor is excited by a direct current power source, and a regenerative current due to electromagnetic energy accumulated in the inductor is supplied to the light emitting diode when the direct current power source is turned off to light the light emitting diode with high efficiency. In other words, a series circuit of an inductor and a light emitting diode is connected to a DC power source via a switching element, and the LED lighting is connected to the series circuit in parallel and has a diode that forms a closed circuit with the series circuit when the switching element is turned off. An apparatus is known (for example, refer to Patent Document 1). In this LED lighting device, a resistor is connected in series with the light emitting diode so that a predetermined current flows through the light emitting diode.
Japanese Patent Laid-Open No. 2002-184588 (page 3, FIG. 1)

  In Patent Document 1, if the resistance value of the resistor directly connected to the light emitting diode is large, there is a problem that the power consumed by the resistor becomes large during normal lighting. Further, when the resistance value of the resistor is reduced, there is a problem that the resistor burns out when, for example, the switching element is short-circuited and an overcurrent flows.

  An object of the present invention is to provide an LED lighting device and a lighting fixture capable of lighting a light emitting diode with high efficiency and protecting a current setting resistor from an overcurrent.

  The invention of the LED lighting device according to claim 1 includes a DC power source; an inductor excited by the DC power source; a light emitting diode connected in series to the DC power source together with the inductor; and connected in series to the light emitting diode. A resistor; switching means for opening and closing a connection between the DC power supply and the inductor, light emitting diode and resistor; and a diode connected to form a closed circuit with the inductor, light emitting diode and resistor when the switching means is off Current detection means for detecting a current flowing through the light emitting diode; control means for controlling on / off operation of the switching means in accordance with the current detected by the current detection means; DC power supply, switching means, inductor, light emitting diode, and resistor It is inserted in a series circuit, and current more than a predetermined value is passed through this series circuit. Characterized in that it comprises a; and a circuit breaking means for interrupting the series circuit when it is.

  In the present invention and each of the following inventions, each configuration is as follows unless otherwise specified.

  The DC power supply may be anything that outputs a DC voltage, such as a battery or a rectified or rectified smoothed AC voltage.

  The light emitting diode may be either surface-mounted or bullet-shaped. Further, either one or a plurality of them may be used, and in the case of a plurality, a series connection or a series-parallel connection is allowed.

  The resistor sets a current flowing through the light emitting diode.

  The current detection means may detect directly or may detect current corresponding to the current flowing through the light emitting diode.

  “Current greater than or equal to a predetermined value” refers to a current value at which the resistor is not thermally damaged or destroyed even when a current continuously flows through the resistor, and is appropriately set according to the rated capacity of the resistor.

  According to the present invention, for example, when the switching means is short-circuit broken due to an overvoltage from the outside, and a current exceeding a predetermined value flows through a series circuit of the DC power supply, the switching means, the inductor, the light emitting diode, and the resistor, the circuit interruption means As a result, the series circuit is interrupted and no current flows through the series circuit.

  The invention of the LED lighting device according to claim 2 is the LED lighting device according to claim 1, characterized in that the circuit interruption means is a non-self-reset type component.

  The non-self-returning part is, for example, a fuse.

  According to the present invention, since the circuit interruption means is a non-self-reset type component, when a current exceeding a predetermined value flows through the series circuit of the DC power supply, the switching means, the inductor, the light emitting diode, and the resistor, The series circuit is interrupted.

  The invention of the LED lighting device according to claim 3 includes: a direct current power supply; an inductor excited by the direct current power supply; a light emitting diode connected in series to the direct current power supply together with the inductor; and connected in series to the light emitting diode A resistor; switching means for opening and closing a connection between the DC power supply and the inductor, light emitting diode and resistor; and a diode connected to form a closed circuit with the inductor, light emitting diode and resistor when the switching means is off Current detection means for detecting a current flowing through the light emitting diode; control means for controlling on / off operation of the switching means in accordance with the current detected by the current detection means; DC power supply, switching means, inductor, light emitting diode, and resistor It is inserted in a series circuit, and current more than a predetermined value is passed through this series circuit. Characterized in that it comprises a; and current limiting means for limiting a current so that it is not.

  The current limiting means is a current limiting element such as a resistor connected in series to a series circuit of a DC power source, a switching means, an inductor, a light emitting diode, and a resistor when a current of a predetermined value or more flows.

  According to the present invention, for example, when the switching means is short-circuited and broken by an overvoltage from the outside, and a current exceeding a predetermined value flows through a series circuit of the DC power supply, the switching means, the inductor, the light emitting diode, and the resistor, the current limiting means Thus, a current exceeding a predetermined value does not flow through the series circuit.

  According to a fourth aspect of the present invention, there is provided the LED lighting device according to the third aspect, wherein the current limiting means is an electric element whose impedance increases as the current increases.

  The electric element is, for example, a positive characteristic thermistor. As the current increases, the temperature rises and the impedance increases.

  According to the present invention, when a current exceeding a predetermined value flows through a series circuit of a DC power supply, switching means, inductor, light emitting diode, and resistor, the impedance of the electrical elements connected in series to the series circuit increases. The current exceeding the predetermined value does not flow in the circuit.

  The invention of a lighting fixture according to claim 5 comprises the LED lighting device according to any one of claims 1 to 4; and a lighting fixture body in which the LED lighting device is disposed. And

  According to the present invention, since the LED lighting device according to any one of claims 1 to 4 is provided, a current of a predetermined value or more flows through a series circuit of the DC power supply, the switching means, the inductor, the light emitting diode, and the resistor. Sometimes, a luminaire is provided in which the thermal breakdown of a resistor that sets the current flowing in the light emitting diode is prevented.

  According to the first aspect of the present invention, when the current exceeding a predetermined value flows through the series circuit of the DC power source, the switching means, the inductor, the light emitting diode, and the resistor, the series circuit is interrupted by the circuit interrupting means. It is possible to prevent thermal destruction of a resistor having a small resistance value that sets the current flowing through the circuit board, and to prevent the resistor from falling from the circuit board.

  According to the invention of claim 2, when a current exceeding a predetermined value flows through the series circuit of the DC power supply, switching means, inductor, light emitting diode and resistor, the series circuit is continuously cut off by the non-self-reset type component. Therefore, it is possible to more safely prevent the thermal destruction of the resistor that sets the current flowing through the diode.

  According to the invention of claim 3, when a current exceeding a predetermined value flows through the series circuit of the DC power supply, the switching means, the inductor and the light emitting diode, the current limiting means prevents the current exceeding the predetermined value from flowing through the series circuit. Therefore, it is possible to prevent thermal destruction of the resistor that sets the current flowing through the diode, and it is possible to prevent the resistor from falling from the circuit board.

  According to the invention of claim 4, when a current of a predetermined value or more flows through the series circuit of the DC power supply, the switching means, the inductor, the light emitting diode, and the resistor, the impedance of the electric element connected in series to the series circuit is large. Thus, since a current exceeding a predetermined value does not flow through the series circuit, it is possible to prevent thermal destruction of the resistor that sets the current flowing through the diode.

  According to the invention of claim 5, since the LED lighting device according to any one of claims 1 to 4 is provided, it is possible to prevent the resistor that sets the current flowing through the diode from being thermally destroyed and falling from the circuit board. Thus, it is possible to provide a lighting fixture in which the lighting fixture body is not easily damaged by heat.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.

  FIG. 1 is a circuit diagram of an LED lighting device showing a first embodiment of the present invention. The LED lighting device 1 includes a DC power supply 2, an inductor L1, a light emitting diode 3, a field effect transistor FET1 as a switching means, a diode D1, a resistor R1, a current detection circuit 4 as a current detection means, a control circuit 5 as a control means, and It has a relay 6 as a circuit interruption means.

  The DC power source 2 is formed to output a DC voltage by rectifying and smoothing a commercial AC voltage, for example. The inductor L1 is excited by a current supplied from the DC power supply 2 and accumulates electromagnetic energy. The light emitting diode 3 has a resistor R1 connected in series and is further connected in series with the DC power source 2 together with the inductor L1. The light emitting diode 3 is formed to emit, for example, white light when a current flows. The resistor R1 sets a current flowing through the light emitting diode 3, and is set to a low resistance value.

  The field effect transistor FET1 is ON / OFF controlled by the control circuit 5, and opens and closes the connection between the DC power source 2, the inductor L1, the light emitting diode 3, and the resistor R1. The diode D1 is connected in parallel with the series circuit of the inductor L1, the light emitting diode 3, the resistor R1, the current detection circuit 4, and the relay contact 6a. When the field effect transistor FET1 is off, the diode D1 is closed with the series circuit. Is forming.

  In the current detection circuit 4, the primary winding 4 a is connected in series with the light emitting diode 3, and the current flowing through the light emitting diode 3 is detected by the secondary winding 4 b and output to the control circuit 5. .

  The control circuit 5 is configured to control the on / off operation of the field effect transistor FET1 in accordance with the current detected by the current detection circuit 4. That is, the on period and the off period of the field effect transistor FET1 are adjusted so that the current flowing through the light emitting diode 3 becomes a predetermined constant current value.

  The relay contact 6 a is a normally closed contact of the relay 6, and is connected in series with the light emitting diode 3 via the current detection circuit 4. The relay coil 6 b is connected to the tertiary winding 4 c of the current detection circuit 4. The relay coil 6b opens the relay contact 6a when the current flowing through the light emitting diode 3 is equal to or greater than a predetermined value set in advance. As a result, the connection between the DC power supply 2 and the light emitting diode 3 is cut off, and no current flows through the light emitting diode 3.

  The relay contact 6a only needs to be inserted in any part of the series circuit of the DC power supply 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, and the resistor R1. That is, since the current flowing through the series circuit is the current flowing through the resistor R1, when a current of a predetermined value or more flows through the series circuit, the relay contact 6a is opened to shut off the series circuit. Also good.

  A smoothing capacitor C1 is connected in parallel with the light emitting diode 3 between the inductor L1 and the light emitting diode 3. For example, the connection of the light emitting diode 3 is confirmed by the smoothing capacitor C1. That is, when the light emitting diode 3 is not lit even when the DC power supply 2 is turned on, if a predetermined voltage is detected across the smoothing capacitor C1, the lead wire connected to the light emitting diode 3 is disconnected. It can be confirmed that the light emitting diode 3 is not connected.

  Next, the operation of the LED lighting device 1 will be described.

  When the DC power supply 2 is turned on, the control circuit 5 performs on / off control of the field effect transistor FET1. When the field effect transistor FET1 is turned on, the current supplied from the DC power source 2 flows through the path of the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, the relay contact 6a, and the resistor R1, and the light emitting diode 3 lights up and electromagnetic energy is accumulated in the inductor L1. When the field effect transistor FET1 is turned off, a current due to the electromagnetic energy accumulated in the inductor L1 flows in a closed circuit of the inductor L1, the light emitting diode 3, the current detection circuit 4, the relay contact 6a, the resistor R1, and the diode D1, While the light emitting diode 3 is turned on, the electromagnetic energy of the inductor L1 is consumed. The light emitting diode 3 is turned on by the regenerative current due to the electromagnetic energy accumulated in the inductor L1, and the resistance value of the resistor R1 is small and the power consumption at the resistor R1 is small. Therefore, the light emitting diode 3 is turned on with high efficiency. .

  The control circuit 5 adjusts the on period and the off period of the field effect transistor FET1 so that the current flowing through the light emitting diode 3 detected by the current detection circuit 4 becomes a predetermined constant current value.

  Then, when an overvoltage is superimposed on the DC power supply 2 from the external power supply and this overvoltage is applied to the field effect transistor FET1 and the field effect transistor FET1 is destroyed and short-circuited, the current from the DC power supply 2 is changed to the field effect transistor. It flows continuously through the path of FET1, inductor L1, light emitting diode 3, current detection circuit 4, relay contact 6a and resistor R1. At this time, since the resistance value of the inductor L1, the resistance value of the primary winding 4a of the current detection circuit 4, and the resistance value of the resistor R1 are small, an overcurrent flows.

  If the overcurrent is equal to or greater than a predetermined value set in advance, the relay coil 6b is energized, and the DC power source 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, the relay contact 6a, and the resistance From the series circuit of R1, the relay contact 6a is opened, the series circuit is cut off, and no current flows.

  The predetermined value is a resistance having a small resistance value even when a current continuously flows through a series circuit of the DC power source 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, the relay contact 6a, and the resistor R1. R1 is set to a current value that is not thermally destroyed. Therefore, when a current greater than or equal to a predetermined value flows through the series circuit, the series circuit is cut off, thereby preventing thermal destruction of the resistor R1 and preventing dropping from the circuit board.

  Next, a second embodiment of the present invention will be described.

  2 to 3 are circuit diagrams of an LED lighting device showing a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to a part same as FIG. 1, and description is abbreviate | omitted.

  An LED lighting device 7 shown in FIG. 2 is obtained by connecting a pattern fuse 8 as a circuit breaking means in place of the relay contact 6a in the LED lighting device 1 shown in FIG. The fuse 8 is a non-self-reset type part and is selected to melt when a current of a predetermined value or more flows.

  For example, the field-effect transistor FET1 is destroyed and short-circuited, and a current of a predetermined value or more flows through the series circuit of the DC power supply 2, the field-effect transistor FET1, the inductor L1, the light-emitting diode 3, the current detection circuit 4, the fuse 8, and the resistor R1. Sometimes, the fuse 8 is melted to interrupt the series circuit, so that the resistance R1 having a small resistance value is prevented from being thermally destroyed.

  Further, the LED lighting device 9 shown in FIG. 3 is a low melting point metal as a circuit interruption means at one end of the primary winding 4a of the current detection circuit 4 in place of the relay contact 6a in the LED lighting device 1 shown in FIG. A wire 10 is connected, and the low melting point metal wire 10 is connected to the light emitting diode 3 via a lead wire 11. The low melting point metal wire 10 is hard to dissipate heat and is wired. The low melting point metal wire 10 is melted when a current of a predetermined value or more flows.

  For example, the field effect transistor FET1 is destructively short-circuited, and a current exceeding a predetermined value flows in a series circuit of the DC power supply 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, the low melting point metal wire 10, the current detection circuit 4, and the resistor R1. When the current flows, the low melting point metal wire 10 is melted and interrupts the series circuit, so that the thermal resistance of the resistor R1 having a small resistance value is prevented.

  Next, a third embodiment of the present invention will be described.

  FIG. 4 is a circuit diagram of an LED lighting device showing a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to a part same as FIG. 2, and description is abbreviate | omitted.

  The LED lighting device 12 shown in FIG. 4 is the LED lighting device 7 shown in FIG. 2, in which a resistor R2 that doubles as the current detection circuit 4 and the resistor R1 is connected in series to the light emitting diode 3.

  Then, the current flowing through the resistor R2 is converted into a voltage and input to the control circuit 5. And since the electric current detection circuit 4 and resistance R1 are combined, the LED lighting device 12 is simplified.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 5 is a circuit diagram of an LED lighting device showing a fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to a part same as FIG. 1, and description is abbreviate | omitted.

  The LED lighting device 13 shown in FIG. 5 is obtained by connecting a resistor R3 in parallel with the relay contact 6a in the LED lighting device 1 shown in FIG. Relay contact 6a and resistor R3 form a current limiting means.

  When the relay contact 6a is opened, the resistor R3 is connected in series to the series circuit of the DC power source 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, and the resistor R1, and the series circuit is connected to the resistor R3. The resistance value is set in advance so that a current exceeding a predetermined value does not flow.

  When the field effect transistor FET1 is destroyed and short-circuited due to an external overvoltage or the like, the current from the DC power supply 2 is passed through the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, the relay contact 6a, and the resistor R1. Overcurrent flows continuously. At this time, the overcurrent is detected by the tertiary winding 4c of the current detection circuit 4, and the relay coil 6b is energized when the overcurrent is equal to or greater than a predetermined value set in advance. As a result, the relay contact 6a is opened, and a series circuit of the field effect transistor FET1, inductor L1, light emitting diode 3, current detection circuit 4, resistor R3 and resistor R1 is connected to the DC power source 2, and a predetermined value is applied to the series circuit. Less current will flow. Therefore, thermal destruction of the resistor R1 having a small resistance value is prevented.

  Next, a fifth embodiment of the present invention will be described.

  FIG. 6 is a circuit diagram of an LED lighting device showing a fifth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to a part same as FIG. 2, and description is abbreviate | omitted.

  The LED lighting device 14 shown in FIG. 6 is the same as the LED lighting device 7 shown in FIG. 2 except that a positive temperature coefficient thermistor 15 as a current limiting means is connected instead of the fuse 8 as a circuit interruption means. The thermistor 15 is an electric element whose impedance increases as the current increases. That is, the thermistor 15 has a very small resistance value when a preset constant current value flows through the light emitting diode 3, and the resistance value increases when an overcurrent flows. The electrical characteristics are selected in advance so that the current does not flow continuously. The thermistor 15 also serves as the resistor R1.

  For example, when the field effect transistor FET1 is destroyed and short-circuited and a current of a predetermined value or more flows through a series circuit of the DC power supply 2, the field effect transistor FET1, the inductor L1, the light emitting diode 3, the current detection circuit 4, and the thermistor 15, The resistance value (impedance) of the thermistor 15 increases, and a current of a predetermined value or more does not flow through the series circuit. Therefore, thermal damage and destruction of circuit components such as the inductor L1 and the light emitting diode 3 are prevented.

  Next, a sixth embodiment of the present invention will be described.

  FIG. 7 is a partially cutaway schematic side view of an LED lighting apparatus showing a sixth embodiment of the present invention. Note that the same parts as those in FIG.

  A lighting fixture 16 shown in FIG. 7 is a direct-mounted lighting fixture arranged on the ceiling surface 17, and includes the LED lighting device 1 and the lighting fixture body 18 shown in FIG.

  The luminaire main body 18 is formed in a box shape having an opening 18a on the lower surface, and a substrate 19 is disposed therein. A plurality of light emitting diodes 3 connected in series are arranged on the substrate 19 so as to face the opening 18a. And the lighting fixture main body 18 is supported by the adapter 21 by the connecting pipes 20 and 20 of predetermined length provided in the upper surface side.

  The adapter 21 is formed in a substantially cylindrical shape, and houses the LED lighting device 22 therein. The LED lighting device 22 is obtained by removing the light emitting diode 3 from the LED lighting device 1. The adapter 21 is connected to a hooking ceiling 23 disposed on the ceiling surface 17. Then, lead wires 24 and 24 are led out from the output terminal of the LED lighting device 22, and the lead wires 24 and 24 are inserted into the connecting pipes 20 and 20 and connected to the substrate 19.

  In the lighting fixture 16, when a current (overcurrent) of a predetermined value or more flows through the LED lighting device 22, the resistor R1 having a small resistance value that sets the current flowing through the light emitting diode 3 is protected. Is prevented from falling from the substrate 19 due to thermal destruction.

  In addition, the lighting fixture main body 18 is not limited to a box shape, and the shape thereof may be any shape such as a circular shape. Further, the lighting fixture 16 is not limited to a direct-mounted lighting fixture, but may be used for a hanging lighting fixture or an embedded lighting fixture such as a downlight.

The circuit diagram of the LED lighting device which shows the 1st Embodiment of this invention. The circuit diagram of the LED lighting device which shows the 2nd Embodiment of this invention. Similarly, the circuit diagram of another LED lighting device. The circuit diagram of the LED lighting device which shows the 3rd Embodiment of this invention. The circuit diagram of the LED lighting device which shows the 4th Embodiment of this invention. The circuit diagram of the LED lighting device which shows the 5th Embodiment of this invention. The partial notch schematic side view of the lighting fixture which shows the 6th Embodiment of this invention.

Explanation of symbols

D1 ... Diode FET1 ... Field effect transistor L1 as a switching element ... Inductor R1 ... Resistance R3 ... Resistance 1, 7, 9, 12, 13, 14 as current limiting means ... LED lighting device 2 ... DC power supply 3 ... Light emitting diode 4 ... Current detection circuit 5 as current detection means ... Control circuit 6 as control means ... Relay 8 as circuit interruption means ... Fuse 10 as circuit interruption means ... Low melting point metal wire 13 as circuit interruption means ... Current limitation means Resistance 15 ... thermistor 16 as current limiting means ... lighting fixture 18 ... lighting fixture body

Claims (5)

DC power supply;
An inductor excited by a DC power source;
A light emitting diode connected in series with a DC power source together with an inductor;
A resistor connected in series with the light emitting diode;
Switching means for opening and closing a connection between the DC power source and the inductor, the light emitting diode and the resistor;
A diode connected to form a closed circuit with the inductor, the light emitting diode and the resistor when the switching means is off;
Current detection means for detecting current flowing in the light emitting diode;
Control means for controlling the on / off operation of the switching means according to the current detected by the current detection means;
Circuit interrupting means that is inserted in a series circuit of a DC power supply, switching means, inductor, light emitting diode and resistor, and interrupts the series circuit when a current of a predetermined value or more flows through the series circuit;
The LED lighting device characterized by comprising.   2. The LED lighting device according to claim 1, wherein the circuit interrupting means is a non-self-returning part. DC power supply;
An inductor excited by a DC power source;
A light emitting diode connected in series with a DC power source together with an inductor;
A resistor connected in series with the light emitting diode;
Switching means for opening and closing a connection between the DC power source and the inductor, the light emitting diode and the resistor;
A diode connected to form a closed circuit with the inductor, the light emitting diode and the resistor when the switching means is off;
Current detection means for detecting current flowing in the light emitting diode;
Control means for controlling the on / off operation of the switching means according to the current detected by the current detection means;
Current limiting means that is inserted in a series circuit of a DC power supply, switching means, inductor, light emitting diode, and resistor, and that limits the current so that a current exceeding a predetermined value does not flow through the series circuit;
The LED lighting device characterized by comprising.   4. The LED lighting device according to claim 3, wherein the current limiting means is an electric element whose impedance increases as the current increases. An LED lighting device according to any one of claims 1 to 4;
A lighting fixture main body provided with the LED lighting device;
The lighting fixture characterized by comprising.

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