JP2014146634A - Led driving device and led lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED driving device and an LED lighting device capable of preventing function deterioration as a lighting device as much as possible even when overheating of a heating component is prevented.SOLUTION: An LED driving device includes: a constant current circuit 3 in which an LED 4 is driven at constant current; a thermistor 6 which detects overheating of a heating component; and a latch circuit 5 in which, when the overheating is detected by the thermistor 6, output current of the constant current circuit 3 is reduced to be kept in a low output state and the low output state is maintained.

Description

  The present invention relates to an LED driving device and an LED lighting device.

  In recent years, LED (Light Emitting Diode) lighting devices that save power and have a long life are rapidly spreading. It is known that a current limiting element such as a thermistor is provided in an input circuit as a countermeasure against an inrush current when power is turned on in this type of lighting device (for example, see Patent Document 1).

JP 2012-174508 A

  Conventionally, when the heat generating component in the LED lighting device becomes high temperature, the LED is turned off or the LED blinks. Controlling the lighting of the LED in this manner is necessary to prevent overheating of the heat-generating component, but greatly reduces the function as a lighting device.

  An object of the present invention is to provide an LED driving device and an LED lighting device capable of preventing a functional deterioration as a lighting device as much as possible even when overheating of a heat-generating component is prevented.

  According to one aspect of the present invention, a constant current circuit that drives an LED at a constant current, an overheating detector that detects overheating of a heat-generating component, and when overheating is detected by the overheating detector, An LED driving device is provided that includes a latch circuit that reduces an output current of a current circuit to a low output state and maintains the low output state.

  According to another aspect of the present invention, a constant current circuit that drives the LED at a constant current, an angle detector that detects an angle of the light emitting surface of the LED, and an angle of the light emitting surface detected by the angle detector. There is provided an LED driving device comprising a control circuit for controlling the constant current circuit so that the LED is lit only when is at a predetermined angle.

  Moreover, according to the other aspect of this invention, an LED lighting apparatus provided with the LED drive device of the said aspect is provided.

  ADVANTAGE OF THE INVENTION According to this invention, even when preventing the overheating of a heat-emitting component, the LED drive device and LED lighting device which can prevent the function fall as an illuminating device as much as possible can be provided.

The typical block block diagram of the LED drive device which concerns on 1st Embodiment. The typical circuit block diagram of the LED drive device which concerns on a basic technique. The flowchart which shows operation | movement of the LED drive device which concerns on basic technology. The typical circuit block diagram of the LED drive device which concerns on 1st Embodiment. The flowchart which shows operation | movement of the LED drive device shown by FIG. The another typical circuit block diagram of the LED drive device which concerns on 1st Embodiment. The flowchart which shows operation | movement of the LED drive device shown by FIG. It is explanatory drawing of the LED illuminating device which concerns on 1st Embodiment, Comprising: (a) The typical plane block diagram in the state in which two electric power feeding pins were located in a line with the perpendicular direction, (b) The typical side block diagram. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the LED illuminating device which concerns on 1st Embodiment, Comprising: (a) Typical plane block diagram in the state in which two electric power supply pins were located in a line with the horizontal direction, (b) The typical side block diagram, (C) The typical AA cross-section block diagram. The typical plane block diagram of the LED board with which the LED lighting apparatus which concerns on 1st Embodiment is provided. The typical plane block diagram which expanded a part of LED board shown by FIG. It is explanatory drawing of the method of mounting a thermistor on the LED board shown by FIG. 10, Comprising: (a) The typical plane block diagram which expanded a part of LED board, (b) The typical cross-section block diagram of the part. It is explanatory drawing of the problem which the LED illuminating device which concerns on 2nd Embodiment solves, Comprising: (a) Typical cross-sectional block diagram which shows the state which mounted | wore with the nozzle | cap | die, (b) Inserting a feeding pin into a socket The typical cross-sectional block diagram which shows the state fitted to the opening | mouth, (c) The typical cross-sectional block diagram which shows the state of the half-hanging which the electric power feeding pin is not fitted to the insertion port of the socket, (d) LED lighting apparatus The typical cross-section block diagram which shows the state which may fall. The typical block block diagram of the LED drive device which concerns on 2nd Embodiment. The typical block block diagram of the 4-way sensor with which the LED drive device which concerns on 2nd Embodiment is provided. The typical circuit block diagram of the 4-way sensor with which the LED drive device which concerns on 2nd Embodiment is provided. The figure which shows the logic table | surface of the 4-way sensor shown by FIG. The figure which shows the AND circuit into which the output of the four-direction sensor shown by FIG. 16 is input. It is explanatory drawing of the mounting method of the 4-way sensor with which the LED lighting apparatus which concerns on 2nd Embodiment is equipped, Comprising: (a) Typical plane block diagram of LED board, (b) Riser board connected to the LED board FIG. Explanatory drawing of another mounting method of the 4-way sensor with which the LED lighting apparatus which concerns on 2nd Embodiment is provided. Explanatory drawing of another mounting method of the 4-way sensor with which the LED lighting apparatus which concerns on 2nd Embodiment is provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness of each component and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the embodiments of the present invention include the material, shape, and structure of each component. The arrangement is not specified below. Various modifications can be made to the embodiment of the present invention within the scope of the claims.

[First Embodiment]
Hereinafter, the first embodiment will be described in detail with reference to FIGS.

(LED drive device)
As shown in FIG. 1, the LED driving device according to the first embodiment includes a constant current circuit 3 that drives the LED 4 at a constant current, an overheating detector that detects overheating of a heat-generating component, and an overheating detector. When overheating is detected by the above, a latch circuit 5 is provided that reduces the output current of the constant current circuit 3 to a low output state and maintains the low output state.

  Here, the overheating detector is the thermistor 6 whose resistance value changes with temperature, and the latch circuit 5 may put the constant current circuit 3 in a low output state based on the resistance value of the thermistor 6. .

  Further, as shown in FIG. 4, the thermistor 6 is a PTC thermistor 6a whose resistance value increases with an increase in temperature, and the latch circuit 5 has a constant current when the resistance value of the PTC thermistor 6a exceeds a predetermined value. The circuit 3 may be in a low output state.

  As shown in FIG. 6, the thermistor 6 is an NTC thermistor 6b whose resistance value decreases with increasing temperature, and the latch circuit 5 has a constant current when the resistance value of the NTC thermistor 6b falls below a predetermined value. The circuit 3 may be in a low output state.

  12A, the LED board 30 on which the LED 4 is mounted and the thermistor board 40 on which the thermistor 6 is mounted are provided, and the thermistor board 40 is wired to the connector 32 provided on the LED board 30. 43 may be connected.

  Further, as shown in FIG. 12B, the transistor Q <b> 1 that is a heat generating component and the thermistor substrate 40 may be fastened together with the LED substrate 30.

  Further, the latch circuit 5 may bring the constant current circuit 3 into a low output state by increasing the resistance value of the sense resistor for monitoring the current.

  As shown in FIG. 4 or FIG. 6, the first sense resistor Rs1 and the second sense resistor Rs2 having a resistance value larger than that of the first sense resistor Rs1 are provided, and the latch circuit 5 includes the first sense resistor Rs1 to the first sense resistor Rs1. The constant current circuit 3 may be brought into a low output state by switching to the two sense resistor Rs2.

  Further, the resistance value of the second sense resistor Rs2 may be 1.3 times or more the resistance value of the first sense resistor Rs1.

  Further, the second sense resistor Rs2 may be a variable resistor whose resistance value can be changed.

  The latch circuit 5 may maintain the low output state of the constant current circuit 3 until the power supply from the main power supply is turned off.

  A schematic block configuration of the LED driving device according to the first embodiment is expressed as shown in FIG. As shown in FIG. 1, the LED driving device includes an AC power source 1, a rectifying / smoothing circuit 2, a constant current circuit 3, an LED 4, a latch circuit 5, and a thermistor 6. The AC power source 1 is, for example, a 100V AC power source. The rectifying / smoothing circuit 2 is an AC / DC converter that rectifies and smoothes the alternating current of the AC power source 1. The constant current circuit 3 is, for example, a DC / DC converter that outputs a constant current of 120 mA to the LED 4. The LED 4 is a light source of the LED lighting device. When overheating is detected by the thermistor 6, the latch circuit 5 reduces the output current of the constant current circuit 3 to a low output state and maintains the low output state. The thermistor 6 is an element whose resistance value changes with changes in temperature. According to such a configuration, when overheating of the heat generating component is detected, the low output state of the constant current circuit 3 can be maintained until the power supply from the main power supply is turned off.

(Basic technology)
A schematic circuit configuration of the LED driving device according to the basic technology is expressed as shown in FIG. The range shown in FIG. 2 corresponds to the range surrounded by the dotted line in FIG. As shown in FIG. 2, power is supplied from the power supply line to the Vin terminal of the LED driver IC 10 via the regulator 11. When the voltage fed back to the Is terminal of the LED driver IC 10 reaches the reference voltage of the comparator 13, the output of the Gd terminal of the LED driver IC 10 is turned off to make the current constant. Since the transistor Q generates heat when it is turned ON / OFF as a switch, a PTC thermistor 6a is installed in the vicinity of the transistor Q to be thermally coupled. The PTC thermistor 6a is a thermistor whose resistance value increases with increasing temperature. A step-down circuit is formed by the diode D and the coil L, and the LED 4 is connected to the step-down circuit. In addition, a sense resistor Rs for monitoring the current flowing through the LED 4 is connected in parallel with the PTC thermistor 6a.

  The operation of the LED driving device according to the basic technique is expressed as shown in FIG. First, when the transistor Q, which is a heat generating component, is heated (step S1), the resistance value of the PTC thermistor 6a installed in the vicinity thereof increases (step S2), and the combined resistance of the sense resistor Rs and the PTC thermistor 6a is increased. The resistance value increases (step S3). As a result, the Is terminal voltage increases even at a low current and reaches the reference voltage of the comparator 13 (step S4), so that the output current can be reduced (step S5). As a result, when the transistor Q, which is a heat generating component, cools (step S6), the resistance value of the PTC thermistor 6a decreases (step S7), and the output current increases (step S8). Such an operation is repeated, and the lighting of the LED 4 undulates.

(Specific example of LED driving device)
A schematic circuit configuration of the LED driving device according to the first embodiment is expressed as shown in FIG. As shown in FIG. 4, power is supplied from the power supply line to the Vin terminal of the LED driver IC 10 via the regulator 11. The LED driver IC 10 includes a regulator 12, a comparator 13, an oscillation circuit 14, a flip-flop 15, and an LED driver 16. When the voltage fed back to the Is terminal of the LED driver IC 10 reaches the reference voltage of the comparator 13, the output of the Gd terminal of the LED driver IC 10 is turned off to make the current constant. Since the transistor Q1 generates heat when it is turned ON / OFF as a switch, a PTC thermistor 6a is installed in the vicinity of the transistor Q1 to be thermally coupled. The vicinity of the transistor Q1 is, for example, a range within 10 mm in diameter with the transistor Q1 as the center. A step-down circuit is formed by the diode D and the coil L, and the LED 4 is connected to the step-down circuit.

  Here, in the first embodiment, as shown in FIG. 4, the latch circuit 5 is formed by transistors Q4 and Q5 and resistors R1 to R4. A startup delay capacitor C is connected to the transistor Q4. Further, the first sense resistor Rs1 is connected to the transistor Q2, and the second sense resistor Rs2 is connected to the transistor Q3. The resistance value of the second sense resistor Rs2 is larger than the resistance value of the first sense resistor Rs1, and is, for example, 1.3 times or more the resistance value of the first sense resistor Rs1. The resistor 5 and the PTC thermistor 6a may be mounted on a different board from other components (described later). The resistor R5 and the PTC thermistor 6a divide the voltage at the same level as the power supplied to the LED driver IC 10.

  The operation of the LED driving device shown in FIG. 4 is expressed as shown in FIG. First, when the main power is turned on, the transistor Q4 is turned on and the transistor Q2 is turned on (step S11). As a result, only the first sense resistor Rs1 connected to the transistor Q2 is used as the sense resistor (step S12). Next, when the transistor Q1, which is a heat generating component, is heated (step S13), the resistance value of the PTC thermistor 6a installed in the vicinity thereof increases (step S14). When the resistance value of the PTC thermistor 6a is increased, the voltage is divided by the resistor R5 and the PTC thermistor 6a, so that the transistor Q6 is turned on. As a result, the transistor Q5 is turned on and the transistor Q4 is turned off. Thus, when the transistors Q4 and Q5 are turned ON / OFF, the transistor Q2 is turned OFF and the transistor Q3 is turned ON (step S15). As a result, only the second sense resistor Rs2 connected to the transistor Q3 is used as the sense resistor (step S16).

  As already described, since the resistance value of the second sense resistor Rs2 is larger than the resistance value of the first sense resistor Rs1, the output current can be reduced. For example, when the resistance value of the second sense resistor Rs2 is 1.3 times the resistance value of the first sense resistor Rs1, the output current is reduced by about 30%. When the output current is gradually reduced, it is known that humans begin to sense the change in brightness when the output current is reduced by about 30%. That is, even if the output current is reduced by about 30% in this way, the function as a lighting device is hardly deteriorated. Of course, if the sense resistor Rs2 is a variable resistor, the user can control the strength of the output current.

  When the output current is reduced in this way, the transistor Q1, which is a heat generating component, is cooled (step S17), and the resistance value of the PTC thermistor 6a is reduced, but the ON / OFF of the transistors Q4, Q5 is not switched. Therefore, unlike the basic technology, the lighting of the LED 4 does not wave. Thereafter, when the main power is turned off and the main power is turned on again, the initial state is restored and the transistor Q2 is turned on (step S11).

(Modification of LED driving device)
Another schematic circuit configuration of the LED driving device according to the first embodiment is expressed as shown in FIG. As shown in FIG. 6, an NTC thermistor 6b may be used instead of the PTC thermistor 6a. The NTC thermistor 6b is a thermistor whose resistance value decreases with increasing temperature. The resistor R6 and the NTC thermistor 6b divide the voltage at the same level as the power supplied to the LED driver IC 10. Other configurations are the same as those in FIG.

  The operation of the LED driving device shown in FIG. 6 is expressed as shown in FIG. First, when the main power supply is turned on, the transistor Q4 is turned on and the transistor Q2 is turned on (step S21). As a result, only the first sense resistor Rs1 connected to the transistor Q2 is used as the sense resistor (step S22). Next, when the transistor Q1, which is a heat generating component, is heated (step S23), the resistance value of the NTC thermistor 6b installed in the vicinity thereof decreases (step S24). When the resistance value of the NTC thermistor 6b is decreased, the voltage is divided by the resistor R6 and the NTC thermistor 6b. As a result, the transistor Q6 is turned on. As a result, the transistor Q5 is turned on and the transistor Q4 is turned off. Thus, when the transistors Q4 and Q5 are turned on / off, the transistor Q2 is turned off and the transistor Q3 is turned on (step S25). As a result, only the second sense resistor Rs2 connected to the transistor Q3 is used as a sense resistor (step S26). As a result, when the output current is reduced by, for example, about 30%, the transistor Q1, which is a heat generating component, is cooled (step S27), and the resistance value of the NTC thermistor 6b increases, but the ON / OFF of the transistors Q4 and Q5 is not switched. Therefore, unlike the basic technology, the lighting of the LED 4 does not wave. Thereafter, when the main power is turned off and the main power is turned on again, the initial state is restored and the transistor Q2 is turned on (step S21).

(LED lighting device)
The LED lighting device 20 according to the first embodiment is a lighting device including the LED driving device according to the first embodiment, and is represented as shown in FIGS. 8 and 9. FIG. 8A is a schematic plan configuration diagram in a state where the two power supply pins 23 are arranged in the vertical direction, and FIG. 8B is a schematic side configuration diagram thereof. FIG. 9A is a schematic plan configuration diagram in a state where the two power supply pins 23 are arranged in the horizontal direction, FIG. 9B is a schematic side configuration diagram thereof, and FIG. These are the typical AA cross-section block diagrams.

  As shown in FIGS. 8 and 9, the LED lighting device 20 is a straight tube type LED lamp, and includes a light diffusion cover 21, a base 22, a power supply pin 23, a heat sink 24, and an LED substrate 30. Is provided. The light diffusion cover 21 protects the LEDs 4 mounted on the LED substrate 30 and allows light from the LEDs 4 to pass through while diffusing. The light diffusion cover 21 is made of a resin such as milky white polycarbonate, and is formed in a cylindrical shape. Bases 22 are attached to both ends in the longitudinal direction of the light diffusion cover 21, and two power supply pins 23 that are metal rod-shaped members protrude from each base 22. An LED substrate 30 on which the LEDs 4 are mounted is attached to the upper surface of the heat sink 24. The heat sink 24 is a member for transferring heat from the LED 4 to the outside, and is made of, for example, aluminum. The heat sink 24 has a substantially U-shaped cross section.

(Thermistor mounting method)
A schematic planar configuration of the LED substrate 30 included in the LED lighting device 20 according to the first embodiment is expressed as shown in FIG. As shown in FIG. 10, the LED substrate 30 has a long rectangular shape extending in the longitudinal direction x, and is formed on a base material made of an insulating material such as ceramics such as alumina or glass epoxy resin, for example. A wiring pattern. The LED substrate 30 supports the plurality of LEDs 4 and provides a path for supplying power to them.

  A schematic plan configuration in which a part of the LED substrate 30 shown in FIG. 10 is enlarged is expressed as shown in FIG. Here, the state before mounting the thermistor 6 is shown. As shown in FIG. 11, latch circuit 5, transistors Q1, Q2, Q3, and Q6, LED driver IC 10, first sense resistor Rs1, second sense resistor Rs2, diode D, coil L, and output terminals 31a and 31b to LED4. Etc. are mounted on the LED substrate 30. The latch circuit 5 is formed by an IC in which the transistors Q4 and Q5 and the resistor are combined into one package. Each of the first sense resistor Rs1 and the second sense resistor Rs2 is formed by two parallel combined resistors.

  A schematic plan configuration in which a part of the LED substrate 30 shown in FIG. 10 is enlarged is expressed as shown in FIG. 12A, and a schematic cross-sectional configuration of a part thereof is shown in FIG. 12B. It is expressed in Here, the state after mounting the thermistor 6 is shown. As shown in FIG. 12, the thermistor 6 is mounted on a thermistor substrate 40 different from the LED substrate 30. A connector 32 for passing the power supply Vcc, the signal SIG, and the ground GND is provided on the LED substrate 30, and the thermistor substrate 40 is connected to the connector 32 via the wiring 43. In addition, the transistor Q <b> 1 that is a heat-generating component and the thermistor substrate 40 are fastened together with screws 42 using the through holes 41 formed in the thermistor substrate 40. Thereby, the position of the thermistor 6 can be easily adjusted according to the position of the heat generating component.

  As described above, according to the first embodiment, when overheating of the heat generating component is detected, the low output state of the constant current circuit 3 is maintained, so that the LED 4 is turned off or the LED 4 blinks. There is nothing to do. In other words, even when overheating of the heat-generating component is prevented, it is possible to prevent as much as possible a decrease in function as a lighting device.

  Here, the PTC thermistor 6a and the NTC thermistor 6b are exemplified as the thermistor 6. However, the resistance value of the NTC thermistor 6b greatly decreases (about four digits) as the temperature rises. It is desirable to use a relatively small PTC thermistor 6a. Of course, the overheating detector for detecting overheating of the heat-generating component is not limited to the thermistor 6, and other overheating detectors having the same function can also be used.

[Second Embodiment]
By the way, when installing the LED lighting device 20 on a ceiling surface or the like, it is important to prevent the fall due to half-hanging. That is, as shown in FIG. 13A, the base 22 of the LED lighting device 20 is mounted on the socket S of the lighting fixture, and as shown in FIG. It is necessary to fit the feeding pin 23 protruding from the socket into the socket S. However, as shown in FIG. 13C, the LED lighting device 20 is lit even in a half-hanging state where the power feed pin 23 is not fitted into the socket S, and the LED lighting device remains in a half-hanging state. 20 may be used. In such a case, as shown in FIG. 13D, the LED lighting device 20 may rotate due to vibrations transmitted to the ceiling surface, and the LED lighting device 20 may fall.

(LED drive device)
As shown in FIG. 14, the LED driving device according to the second embodiment includes an angle detector that detects the angle of the light emitting surface of the LED 4, and the angle of the light emitting surface detected by the angle detector is a predetermined angle. And a control circuit 7 that controls the constant current circuit 3 so that the LED 4 is lit only in some cases.

  Here, the angle detector is a four-direction sensor 8 that detects four directions of up, down, left, and right at 90 ° intervals, and the control circuit 7 controls the constant current circuit 3 based on the output of the four-direction sensor 8. Good.

  Further, as shown in FIG. 19, an LED substrate 30 on which the LED 4 is mounted and a riser substrate 50 on which the four-direction sensor 8 is mounted are provided, and the terminal pins 51 of the riser substrate 50 are connected to the LED substrate 30. Good.

  Further, as shown in FIG. 20, an LED substrate 30 on which the LEDs 4 are mounted and a riser substrate 50 on which the four-direction sensor 8 is mounted are provided. It may be connected via.

  The four-direction sensor 8 may be installed in the Z direction when the light emitting surface of the LED 4 is an XY plane.

  A schematic block configuration of the LED driving apparatus according to the second embodiment is expressed as shown in FIG. As shown in FIG. 14, the LED driving device includes an AC power source 1, a rectifying and smoothing circuit 2, a constant current circuit 3, an LED 4, a control circuit 7, and a four-direction sensor 8. The four-direction sensor 8 is an angle detector that detects the angle of the light emitting surface of the LED 4, and detects four directions, up, down, left, and right at 90 ° intervals. Based on the output of the four-direction sensor 8, the control circuit 7 controls the constant current circuit 3 so that the LED 4 is turned on only when the angle of the light emitting surface of the LED 4 is a predetermined angle. Other configurations are the same as those of the first embodiment. According to such a configuration, it is possible to prevent the LED lighting device 20 from being lit in a half-hanging state.

(4-way sensor)
A schematic block configuration of the four-direction sensor 8 provided in the LED driving device according to the second embodiment is expressed as shown in FIG. As shown in FIG. 15, an infrared LED 81 and two phototransistors 82 and 83 are provided inside the four-direction sensor 8. And the output of the phototransistors 82 and 83 by rolling of the spherical body 84 used as a light-shielding object is detected, and four directions of up and down, right and left are detected at intervals of 90 °.

  A schematic circuit configuration of the four-direction sensor 8 included in the LED driving device according to the second embodiment is represented as shown in FIG. 16, and a logic table of the four-direction sensor 8 is represented as shown in FIG. Is done. As shown in FIG. 16, the output of the phototransistor 82 is called “output 1”, and the output of the phototransistor 83 is called “output 2”. In this case, as shown in FIG. 17, the four-direction sensor 8 is 0 ° when the output 1 is low and the output 2 is low, 90 ° when the output 1 is low and the output 2 is high, and the output 1 is high. When output 2 is high, 180 ° is detected, and when output 1 is high and output 2 is low, 270 ° is detected. Here, the light emitting surface of the LED 4 when the LED lighting device 20 is normally installed is set to 180 °, for example. In this case, as shown in FIG. 18, when the output 3 of the AND circuit 85 to which the output 1 and the output 2 are input is High, the LED 4 is turned on, and when it is Low, the LED 4 is not turned on.

(4-way sensor mounting method)
A mounting method of the four-direction sensor 8 included in the LED lighting device 20 according to the second embodiment is expressed as shown in FIG. FIG. 19A is a schematic plan configuration diagram of an LED substrate 30 included in the LED lighting device 20, and FIG. 19B is a schematic plan configuration diagram of a riser substrate 50 connected to the LED substrate 30. is there. As shown in FIG. 19, the four-direction sensor 8 is mounted on the riser substrate 50, and the terminal pins 51 of the riser substrate 50 are connected to the LED substrate 30. Thereby, the 4-way sensor 8 can be installed in the Z direction when the light emitting surface of the LED 4 (the mounting surface of the LED substrate 30) is the XY plane.

  Another mounting method of the four-direction sensor 8 included in the LED lighting device 20 according to the second embodiment is expressed as shown in FIG. As shown in FIG. 20, the riser substrate 50 can be installed in a space existing inside the base 22. In this case, the wiring 52 may be connected to the riser substrate 50 and the wiring 52 may be connected to the connector 32 provided on the LED substrate 30. Of course, also in this case, the four-way sensor 8 is installed in the Z direction when the light emitting surface of the LED 4 is the XY plane.

  Still another mounting method of the four-direction sensor 8 included in the LED lighting device 20 according to the second embodiment is expressed as shown in FIG. FIG. 21 is a combination of the mounting method shown in FIG. 12 and the mounting method shown in FIG. That is, as shown in FIG. 21, the terminal pin 51 of the riser substrate 50 on which the four-direction sensor 8 is mounted may be connected to the LED substrate 30, and the thermistor substrate 40 on which the thermistor 6 is mounted may be connected to the LED substrate 30. . In this case, the angle of the light emitting surface of the LED 4 is detected by the four-direction sensor 8, and overheating of the heat generating component is detected by the thermistor 6.

  As described above, according to the second embodiment, the LED 4 can be turned on only when the angle of the light emitting surface of the LED 4 is a predetermined angle. Therefore, it is possible to prevent the LED lighting device 20 from being lit in a half-hanging state.

  As described above, according to the present invention, it is possible to provide an LED driving device and an LED lighting device that can prevent a function deterioration as a lighting device as much as possible even when overheating of a heat-generating component is prevented.

[Other embodiments]
As described above, the present invention has been described according to the first to second embodiments. However, it should be understood that the descriptions and drawings constituting a part of this disclosure are exemplary and limit the present invention. should not do. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  As described above, the present invention includes various embodiments not described herein.

  The LED driving device and the LED lighting device according to the present invention can be applied to various LED lighting devices such as a straight tube type LED lamp.

3 ... Constant current circuit 4 ... LED
5 ... Latch circuit 6 ... Overheating detector (thermistor)
6a PTC thermistor 6b NTC thermistor 7 Control circuit 8 Angle detector (4-way sensor)
30 ... LED board 32 ... Connector 40 ... Thermistor board 43 ... Wiring 50 ... Riser board 51 ... Terminal pin 52 ... Wiring Rs1 ... First sense resistor Rs2 ... Second sense resistor

Claims (22)

A constant current circuit for driving LEDs at a constant current;
An overheating detector for detecting overheating of the heat generating component;
And a latch circuit that reduces the output current of the constant current circuit to a low output state and maintains the low output state when overheating is detected by the overheat detector. . The overheating detector is a thermistor whose resistance value changes with respect to temperature change,
The LED driving device according to claim 1, wherein the latch circuit sets the constant current circuit to a low output state based on a resistance value of the thermistor. The thermistor is a PTC thermistor whose resistance value increases with increasing temperature,
The LED driving device according to claim 2, wherein the latch circuit sets the constant current circuit to a low output state when a resistance value of the PTC thermistor exceeds a predetermined value. The thermistor is an NTC thermistor whose resistance value decreases with increasing temperature,
The LED driving device according to claim 2, wherein the latch circuit sets the constant current circuit to a low output state when a resistance value of the NTC thermistor becomes a predetermined value or less. An LED substrate on which the LED is mounted;
The LED driving device according to claim 2, further comprising a thermistor substrate on which the thermistor is mounted, wherein the thermistor substrate is connected to a connector provided on the LED substrate via a wiring.   The LED driving device according to claim 5, wherein the heat generating component and the thermistor substrate are fastened together with the LED substrate.   The LED according to claim 1, wherein the latch circuit sets the constant current circuit to a low output state by increasing a resistance value of a sense resistor for monitoring current. Drive device. A first sense resistor;
A second sense resistor having a larger resistance value than the first sense resistor,
8. The LED driving device according to claim 7, wherein the latch circuit switches the constant current circuit to a low output state by switching from the first sense resistor to the second sense resistor.   The LED driving device according to claim 8, wherein a resistance value of the second sense resistor is 1.3 times or more of a resistance value of the first sense resistor.   The LED driving device according to claim 8, wherein the second sense resistor is a variable resistor whose resistance value can be changed.   The LED driving device according to claim 1, wherein the latch circuit maintains a low output state of the constant current circuit until power supply from a main power supply is turned off. An angle detector for detecting the angle of the light emitting surface of the LED;
12. A control circuit that controls the constant current circuit so that the LED is lit only when the angle of the light emitting surface detected by the angle detector is a predetermined angle. The LED drive device of any one of Claims. The angle detector is a four-direction sensor that detects four directions of up, down, left, and right at 90 ° intervals,
The LED driving device according to claim 12, wherein the control circuit controls the constant current circuit based on an output of the four-direction sensor. An LED substrate on which the LED is mounted;
The LED driving device according to claim 13, further comprising: a riser board on which the four-direction sensor is mounted, and terminal pins of the riser board are connected to the LED board. An LED substrate on which the LED is mounted;
The LED driving device according to claim 13, further comprising a riser substrate on which the four-direction sensor is mounted, wherein the riser substrate is connected to a connector provided on the LED substrate via a wiring.   The LED driving device according to claim 14 or 15, wherein the four-direction sensor is installed in a Z direction when a light emitting surface of the LED is an XY plane. A constant current circuit for driving LEDs at a constant current;
An angle detector for detecting the angle of the light emitting surface of the LED;
And a control circuit that controls the constant current circuit so that the LED is lit only when the angle of the light emitting surface detected by the angle detector is a predetermined angle. The angle detector is a four-direction sensor that detects four directions of up, down, left, and right at 90 ° intervals,
The LED driving device according to claim 17, wherein the control circuit controls the constant current circuit based on an output of the four-direction sensor. An LED substrate on which the LED is mounted;
The LED driving device according to claim 18, further comprising: a riser board on which the four-direction sensor is mounted, wherein terminal pins of the riser board are connected to the LED board. An LED substrate on which the LED is mounted;
The LED drive device according to claim 18, further comprising a riser substrate on which the four-direction sensor is mounted, wherein the riser substrate is connected to a connector provided on the LED substrate via a wiring.   The LED driving device according to claim 19 or 20, wherein the four-direction sensor is installed in a Z direction when a light emitting surface of the LED is an XY plane.   An LED lighting device comprising the LED driving device according to any one of claims 1 to 21.

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