JP2009134945A - Led lighting device, and led illumination fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device capable of obtaining a light output equivalent to that at the time of lighting up with DC smooth voltage while reducing high harmonic components of input current. <P>SOLUTION: The LED lighting device includes a full-wave rectifier DB for performing full-wave rectification of a commercial AC power source Vs, a first capacitor C1 connected in parallel with an output terminal of the full-wave rectifier DB, a switching power source circuit 1 whose input terminal is connected with the first capacitor C1 in parallel, a LED light-emitting section 2 connected to an output terminal of the switching power source circuit 1, and a second capacitor C2 connected in parallel to the LED light-emitting section 2. The capacitance of the first capacitor C1 is less than 1 μF, and the second capacitor C2 is set to have a capacitance with which a ripple factor of current flowing in the LED light-emitting section 2 becomes less than one. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an LED lighting device and an LED lighting apparatus for lighting a light emitting diode (hereinafter referred to as “LED”) using a commercial AC power source.

  In recent years, the optical performance of LEDs has increased, and lighting fixtures using LEDs are in a state where they can be replaced with conventional light sources because of their long life. If the performance of LEDs further improves in the future, it will be adopted in the field of general-purpose lighting equipment. Moreover, in order to increase the efficiency of the LED lighting device as a lighting fixture, the efficiency is being increased. For this reason, a constant current type of a switching power supply system using a switching element has been adopted for the lighting device, and such a trend is expected to continue in the future.

  FIG. 9 shows a circuit diagram of a conventional LED lighting device disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2007-189819). Vs is a commercial AC power supply, DB is a full-wave rectifier, C2 is a capacitor, T1 is a transformer, and includes a primary winding n1 and a secondary winding n2. Q1 is a switching element, D1 is a rectifier diode, 13 is a control circuit for the switching element Q1, 2 is an LED light emitting unit, and 14 is a constant current element.

  Next, the operation of the circuit shown in FIG. 9 will be described. AC voltage of commercial AC power supply Vs is rectified by full-wave rectifier DB, smoothed by capacitor C2, converted to high-frequency rectangular wave AC voltage by switching element Q1 such as transformer T1, MOSFET, and rectified by rectifier diode D1. A series circuit of the constant current element 14 and the LED light emitting unit 2 is connected to the pulse voltage. The switching element Q1 is ON / OFF controlled by the control circuit 13.

  FIG. 10 shows a waveform of the secondary voltage Vn2 of the transformer T1 and the pulse voltage Vp obtained by rectification using the rectifier diode D1. The current flowing through the LED light emitting unit 2 is lit by the constant current Ic defined by the constant current element 14 only when the pulse voltage Vp is present.

  An example of the characteristics of the constant current element 14 is shown in FIG. The horizontal axis is the applied voltage, and the vertical axis is the current. When a voltage equal to or higher than the voltage Vc existing in the constant current element 14 is applied, a constant current Ic flows regardless of the applied voltage. The fluctuation of the power supply voltage and the fluctuation of the forward voltage of the LED change so that the voltage applied to the constant current element 14 absorbs the fluctuation of the voltage and the fluctuation of the forward voltage, and the flowing current is kept constant as Ic. Therefore, the power consumption increases or decreases by the fluctuation of the power supply voltage, but the brightness of the LED does not change.

  In the circuit shown in FIG. 9, the LED light emitting unit 2 is turned off when there is no pulse voltage Vp. However, if the pulse voltage Vp is a high frequency of several kHz or more, it cannot be recognized by the human eye that the LED light is off. The light emitting unit 2 seems to be continuously lit.

When the ratio (t / T) of the pulse voltage Vp to one period T of the pulse voltage Vp shown in FIG. 10 is decreased, the luminance of the LED light emitting unit 2 is decreased and the ratio (t / T) of the pulse voltage Vp is increased. And the brightness seems to rise. The ratio (t / T) of the pulse voltage Vp can be adjusted by the control circuit 13.
JP 2007-189819 A

  In a constant current power supply using a constant current element as in Patent Document 1, unless the output voltage is smoothed, a voltage equal to or higher than the voltage Vc in the constant current element 14 cannot be maintained. That is, since the constant current element 14 has a voltage equal to or higher than the voltage Vc as in a diode, the flowing current is kept constant as Ic. In this conventional circuit, the primary side of the transformer T1 Smoothing is performed by a capacitor C2 provided at the subsequent stage of the full-wave rectifier DB. Without this capacitor C2, the output voltage of the full-wave rectifier DB becomes a full-wave pulsating voltage, and therefore a 50/60 Hz AC power supply causes a low-frequency flicker of 100 Hz or 120 Hz. However, since this capacitor C2 exists for smoothing, the harmonic component of the input current becomes large, and there arises a problem that it deviates from the standard value of the harmonic regulation guideline defined in the lighting equipment.

  In addition, the secondary side of the transformer T1 is turned on with the pulse voltage Vp. However, the efficiency decreases in terms of the efficiency of the appliance obtained by dividing the light output (luminous flux) of the luminaire by the input power including the appliance. That is, as with the diode, the LED characteristics exceed the forward voltage Vf, so that a forward current If corresponding thereto flows. In terms of LED specifications, the output light efficiency (the output luminous flux divided by the output power consumption) is the best when the DC current Idc is passed with a DC smoothing voltage with a ripple rate of approximately zero. Therefore, when pulse lighting is performed with the pulse voltage Vp, there is a problem that the current is averaged and smaller than the previous DC current Idc, and the output luminous flux is accordingly reduced. Further, if the pulse voltage Vp is increased to make the average value of the current passed by the pulse equal to the direct current Idc, the peak of the pulse voltage Vp has to be increased, so the rating of the constant current element 14 also increases. There is a problem that it contributes to an increase in cost and may exceed the absolute maximum rating of the peak current of the LED.

  The present invention has been made in view of the above points, and an LED lighting device and an LED lighting apparatus capable of obtaining a light output equivalent to that when lighting with a DC smoothing voltage while reducing a harmonic component of an input current. It is an issue to provide.

  In order to solve the above problem, the invention of claim 1 is connected in parallel to a full-wave rectifier DB for full-wave rectification of the commercial AC power supply Vs and an output terminal of the full-wave rectifier DB, as shown in FIG. The first capacitor C1, the switching power supply circuit unit 1 whose input terminal is connected in parallel to the first capacitor C1, the LED light emitting unit 2 connected to the output terminal of the switching power supply circuit unit 1, and the LED light emitting unit 2 A second capacitor C2 connected in parallel, the capacitance of the first capacitor C1 is less than 1 μF, and the second capacitor C2 is set to a capacitance at which the ripple rate of the current flowing through the LED light emitting unit 2 is less than 1. It is characterized by that.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the switching power supply circuit unit 1 is a flyback power supply circuit (FIG. 2).

  The invention of claim 3 is the invention of claim 1, wherein the switching power supply circuit unit 1 is a step-down chopper circuit (FIG. 4).

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the full wave rectifier DB includes a filter circuit unit 3 at an AC input terminal (FIGS. 1, 2, and 4).

  According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the power consumption of the LED light emitting unit 2 is 20 W or less.

  The invention of claim 6 is an LED lighting apparatus incorporating the LED lighting device according to any one of claims 1 to 5 (FIG. 8).

  In the present invention, since the capacitance of the first capacitor is less than 1 μF, the voltage waveform from the full-wave rectifier to the switching power supply circuit section is almost full-wave pulsating. As described above, since the capacity of the first capacitor is small, the waveform of the input current from the commercial AC power supply is not a capacitor input type current waveform as in the conventional example, but in almost the whole area except for the valley portion of the full wave. Since the current flows in a waveform, it falls within the standard value of the harmonic regulation guidelines established for lighting equipment. Further, since the output voltage waveform also becomes a pulsating voltage in this state, current does not flow in the voltage range of the LED forward voltage Vf or less, so that the capacity of the LED light emitting unit is, for example, 100 times or more the capacity of the first capacitor. By connecting the both ends of the LED in parallel and making the ripple ratio obtained by dividing the fluctuation range of the current flowing through the LED by the effective current less than 1, it is possible to prevent a decrease in light output.

The details of the present invention will be described below with reference to the illustrated embodiments.
(Basic configuration)
A basic configuration of the present invention is shown in FIG. Vs is a commercial AC power supply, DB is a full-wave rectifier, C1 and C2 are capacitors, 1 is a switching power supply circuit unit including a switching element, 2 is an LED light emitting unit, and 3 is a filter circuit unit. The power consumption of the LED light emission part 2 is 20 W or less, for example.

  In the circuit of FIG. 1, a capacitor C1 connected to the DC output terminal of the full-wave rectifier DB is a capacitor having a capacity of less than 1 μF, and has a small capacity for smoothing the output voltage of the full-wave rectifier DB. A pulsating voltage having a full-wave waveform is applied to the switching power supply circuit unit 1 and is switched at a high frequency by an internal switching element to output a pulse voltage. The output of the switching power supply circuit unit 1 is connected in parallel with a capacitor C2 having a larger capacity that satisfies the conditions described later than the capacity of the capacitor C1, and smoothes the pulse voltage. A smoothing voltage is applied to the LED light emitting unit 2 connected in parallel to the capacitor C2.

  At this time, the current flowing through the LEDs 2a to 2d is not completely eliminated even if it is said to be smooth, but the current fluctuation range Ipp (= Imax−Imin) defined by the maximum value Imax and the minimum value Imin. The capacitance of the output capacitor C2 is set so that the ripple rate (Ipp / Ia) divided by the average value Ia of the current flowing through the LED is less than 1. As a result, the optical output obtained by the circuit of FIG. 1 is almost the same as the optical output obtained by a current flowing from a flat DC voltage.

(Embodiment 1)
A circuit diagram of Embodiment 1 of the present invention is shown in FIG. In this embodiment, the switching power supply circuit unit 1 of FIG. 1 is a flyback type DC-DC converter circuit, and the DC-DC converter circuit includes a primary side control circuit 11 and a secondary side control circuit. 12 is controlled. A DC power supply unit 4 including these circuits and the filter circuit unit 3 is formed.

  The LED light emitting unit 2 includes four LEDs 2a to 2d, and the LED 2a to LED 2d are connected in series from the anode to the cathode. When a positive voltage is applied to the anode side of the LED 2a and a negative voltage is applied to the cathode side of the LED 2d, each of the LEDs 2a to 2d emits light. When a voltage equal to or higher than the total of the forward voltages Vf of the LEDs 2a to 2d is applied, a light beam can be obtained from the LEDs according to the value of the flowing current. Since the forward voltage Vf is usually about 3.5 V, if four are connected in series, they can be lit at a DC voltage of 4 × 3.5 V or more.

  The output connector CON2 of the DC power supply unit 4 and the LED light emitting unit 2 are connected by a pair of lead wires 5. The input connector CON1 of the DC power supply unit 4 is connected to an AC power supply voltage (for example, AC100V, 50/60 Hz) from the commercial AC power supply Vs.

  The filter circuit unit 3 of the DC power supply unit 4 is connected to the commercial AC power supply Vs. The filter circuit unit 3 includes a fuse FUSE, a capacitor C3, and a line filter LF. The fuse FUSE is connected in series to one end of the commercial AC power supply Vs, and the capacitor C3, in parallel with the other end of the commercial AC power supply Vs and the output terminal of the fuse FUSE. A line filter LF is connected.

  A full-wave rectifier DB and a capacitor C1 are connected in parallel to the output of the filter circuit unit 3, and a series circuit of a transformer T1 and a switching element Q1 is connected in parallel with the capacitor C1. A capacitor C4 is connected in parallel to both ends of the switching element Q1. A diode D1 is connected to the high potential side of the secondary winding side of the transformer T1, a capacitor C2 and an output connector CON2 are connected in parallel via the diode D1, and the low potential side of the output connector CON2 and the capacitor C2 A resistor R1 for converting the output current Io into a voltage value is connected between the negative electrodes.

  The first control circuit 11 is provided on the primary side of the transformer T1, and outputs a switching signal of the switching element Q1 according to an input value from the feedback terminal FB. The second control circuit 12 is provided on the secondary side of the transformer T1, and receives a value obtained by converting the output current Io into a voltage by the resistor R1, and generates a feedback signal. The light output element of the photocoupler PC1 is connected to the output of the second control circuit 12, and the feedback input terminal FB of the first control circuit 11 is connected to the light receiving element of the photocoupler PC1.

  The circuit operation will be described below. This DC-DC converter circuit is a so-called flyback type DC power supply, and is a partial resonance type having a capacitor C4 connected in parallel to the switching element Q1. The voltage input from the commercial AC power supply Vs is full-wave rectified by the full-wave rectifier DB through the filter circuit unit 3 via the input connector CON1. The full-wave rectified voltage is applied to a series circuit of the transformer T1 and the switching element Q1 via the capacitor C1. The applied voltage waveform at this time is a full-wave rectified pulsating voltage because the capacitance of the capacitor C1 is set to 0.47 μF. That is, the full-wave rectified voltage is not smoothed by the capacitor C1, and a full-wave waveform pulsating voltage is applied to the series circuit of the transformer T1 and the switching element Q1. When the switching element Q1 is closed, a current flows through the transformer T1 and is charged as magnetic energy. When the switching element Q1 is opened, the magnetic energy is output to the output side via the secondary winding and the diode D1. To be released.

  The output voltage is smoothed by the capacitor C2 until the ripple rate becomes less than 1, and is output via the output connector CON2. The voltage output from the DC power supply unit 4 is supplied to the LED light emitting unit 2, and the LEDs 2a to 2d are turned on when the voltage is equal to or greater than the total of the forward voltages Vf of the LEDs 2a to 2d.

  Here, since the capacitance of the capacitor C1 is 0.47 μF, the output voltage of the transformer T1 also has a pulsating waveform. If this is applied to the LED light emitting unit 2 as it is, light is emitted only when the voltage is equal to or higher than the sum of the forward voltages Vf of the LEDs 2a to 2d in the LED light emitting unit 2, so that the light output becomes smaller than when there is no ripple. . Therefore, the capacity of the capacitor C2 is larger than the capacity of the capacitor C1, and is set to 220 μF. At this time, the ripple rate of the output current (current fluctuation range Ipp, that is, the maximum current value Imax−the minimum current value Imin divided by the average current value Ia) is less than 1.

  FIG. 3 shows operation waveforms of this embodiment, where Ch1 is an output current waveform, Ch2 is an input current waveform, and Ch3 is a voltage waveform across the capacitor C1. Ch1 is measured in the 50 mA / 10 mV range, and the current fluctuation width Ipp is 70 mApp (Δ in the waveform indicates the fluctuation width Ipp, Δ: 14 mV, so 14 mA × 50 mA / 10 mV, 70 mApp) Become. Since the average current value is 179 mA, the ripple rate is 0.39, which is less than 1.

  The current flowing through each of the LEDs 2a to 2d flows to the resistor R1 via the output connector CON2, and the resistor R1 generates a voltage corresponding to the current. This voltage is monitored at the IN terminal of the control integrated circuit IC2 (for example, NJM2146 manufactured by New Japan Radio Co., Ltd.) in the second control circuit 12, and compared with the reference voltage of the reference voltage terminal REF, thereby causing the LEDs 2a to 2d to operate. The output of the OUT terminal of the second control circuit 12 is determined according to the flowing current. This output determines the current flowing through the light emitting element of the photocoupler PC1 connected to the control voltage Vcc. A control voltage is fed back from the light receiving element in the photocoupler PC1 to the feedback terminal FB of the control integrated circuit IC1 of the first control circuit 11 (for example, MR 1722 manufactured by Shindengen Co., Ltd.). At this time, the ON width of the switching element Q1 is determined according to the control voltage input to the feedback terminal FB. By operating in this way, control is performed to keep the current flowing through the LEDs 2a to 2d constant.

  In other respects, the power supply Vcc of the first control circuit 11 is supplied with a voltage regulated by the Zener voltage of the Zener diode ZD1 from the voltage line after full-wave rectification via the resistor R8. Naturally, the voltage does not become lower than the inoperative voltage of the control circuit 11. Further, the ZC terminal of the first control circuit 11 is a zero-cross terminal, which monitors the energy release of the transformer T1 so that the switching element Q1 operates in the discontinuous mode.

  By operating in this way, it is cheaper than conventional circuits and can satisfy harmonic regulations, and it does not exceed the absolute maximum rated current of the LED, reducing the light output compared to lighting with a DC smoothed voltage. Can be suppressed.

  In this embodiment, the flyback type DC power source has been described, but it goes without saying that the same effect can be obtained if the DC power source outputs a DC voltage regardless of the type. In addition, the LED light emitting unit 2 has been described with respect to the four LED connection in series, but may be connected in parallel as long as the directions of the anode and the cathode are the same regardless of the number.

(Embodiment 2)
A circuit diagram of Embodiment 2 of the present invention is shown in FIG. In this embodiment, the switching power supply circuit unit 1 of FIG. 1 is a non-insulated step-down chopper circuit. A description of the same circuit as that of the first embodiment will be omitted. The capacitor C1 is also set to 0.47 μF in this embodiment. This circuit is controlled by a control circuit IC3 (for example, MIP552 manufactured by Matsushita Electric Industrial Co., Ltd.) that also serves as a power switching element, and operates as a step-down chopper circuit.

  The LED light-emitting unit 2 composed of a series circuit of LEDs 2a to 2d, the choke L1, the output terminal Q of the control circuit IC3, and the ground terminal G are connected in series to both ends of the capacitor C1. The output terminal Q is connected to the drain terminal of the switching MOSFET inside the control circuit IC3. The ground terminal G is connected to the source terminal of the switching MOSFET inside the control circuit IC3.

  A diode D1 is connected in parallel to the series circuit of the LED light emitting unit 2 and the choke L1, and a capacitor C2 is connected in parallel to the LED light emitting unit 2. The cathode side of the diode D1 is connected to the positive side of the capacitor C2, and the anode side is connected to the negative side of the capacitor C2 via the choke L1.

  Resistors R2, R3, and R8 and capacitors C5 to C7 are connected as control components around the control circuit IC3. The Vdd terminal of the control circuit IC3 is an external reference voltage terminal, and a capacitor C5 is connected to prevent noise at this terminal. The EX terminal of the control circuit IC3 is a terminal that determines the magnitude of the output current to the LED light emitting unit 2, and a resistor R2 and a resistor R3 are connected in series between the Vdd terminal and the circuit ground (ground terminal G), and the divided voltage is obtained. A voltage is applied to the EX terminal. The capacitor C6 is a noise prevention capacitor, similar to the capacitor C5 described above.

  The Vin terminal is a terminal for supplying control power to the control circuit IC3 through this terminal from the power line after full wave rectification after the commercial AC power supply Vs is turned on. Capacitor C7 is a capacitor for preventing noise similar to capacitors C5 and C6.

  Similarly to the first embodiment, the capacitor C2 is set to have a capacitance at which the ripple rate of the current flowing through the LEDs 2a to 2d is less than 1. Here, the capacitance of the capacitor C2 is 100 μF.

  As a circuit operation, the voltage input from the commercial AC power source Vs is first full-wave rectified by the full-wave rectifier DB via the input connector CON1 through the filter circuit unit 3. The full-wave rectified voltage is applied via a capacitor C1 to a parallel circuit of the LED light emitting unit 2 and the capacitor C2, a choke L1, and a series circuit between the output terminal Q and the ground terminal G of the control circuit IC3.

  Immediately after the commercial AC power supply Vs is turned on, control power is supplied from the Vin terminal of the control circuit IC3 to the control circuit IC3, and oscillation starts when the voltage at the Vdd terminal reaches a predetermined voltage. When the voltage between the output terminal Q and the ground terminal G of the control circuit IC3 is substantially 0, that is, when the internal switching element is in the ON state, the output voltage of the full-wave rectifier DB is transmitted via the control circuit IC3 to the LED light emitting unit 2. Are applied to the parallel circuit of the capacitor C2 and the series circuit of the choke L1, and the LEDs 2a to 2d of the LED light emitting section 2 are lit. The waveform after full-wave rectification at this time is almost a full-wave rectified pulsating voltage because the capacitance of the capacitor C1 is set to be as small as 0.47 μF.

  The time width of the above-mentioned ON state is determined by a threshold voltage set inside the control circuit IC3. When the current flowing between the output terminal Q and the ground terminal G in the control circuit IC3 is converted into a voltage and the voltage reaches the threshold voltage, the output terminal Q and the ground terminal G of the control circuit IC3 are in an open state (that is, The internal switching element is turned off. At this time, a regenerative current flows to the parallel circuit of the capacitor C2 and the LED light emitting unit 2 via the diode D1 due to the back electromotive force generated by the energy stored in the choke L1, and the lighting states of the LEDs 2a to 2d are maintained. The cycle T, which is the sum of the ON interval and the OFF interval, that is, the reciprocal switching frequency is fixed to several tens of kHz in the control circuit IC3, so that it is forcibly shifted from the OFF state to the ON state.

  The threshold voltage for setting the time width during which the output terminal Q and the ground terminal G of the control circuit IC3 are in the ON state can be changed by the divided voltage of the EX terminal. By changing the voltage of the EX terminal, the current flowing through the LED of the LED light emitting unit 2 can be set, and a desired light output can be obtained.

  FIG. 5 is an operation waveform of this embodiment, Ch1 is an output current waveform, and Ch4 is a voltage waveform across the capacitor C2. Ch1 is measured in the range of 50 mA / 10 mV, current fluctuation width Ipp is 101 mApp (Δ in the figure indicates fluctuation width Ipp, Δ: 20.2 mV, 20.2 mV × 50 mA / 10 mV 101 mApp). Moreover, since an average electric current value is 170 mA, the ripple rate of the electric current which flows into LED2a-2d will be 0.59.

  A light output φdc obtained by a DC smoothing current that flows when applied to the LED light emitting unit 2 with a commercially available DC power supply device (for example, Techio PA80-1B), and a light output φl when the ripple rate is changed The relationship of the ratio (DC luminous flux ratio = φl / φdc) is shown in FIG. By setting the ripple rate to less than 1, the decrease in the DC light flux ratio can be suppressed to less than 2%, and the decrease in light output can be suppressed as compared with the case of lighting with a DC smoothing voltage.

  As described above, by setting the capacitance value of the capacitor C1 to be less than 1 μF, it is possible to satisfy the provisions of the harmonic guideline, and the ripple value of the current flowing through the LED light emitting unit 2 is set to the capacitance value of the capacitor C2. By setting it to be less than 1, it is possible to obtain a light output that is almost the same as the light output when lighting with a DC smoothed voltage.

  In addition, it can be said in common with the first and second embodiments that the inrush current generated when the power is turned on can be reduced by lowering the capacitance value of the capacitor C1, so that the number of LED lighting fixtures in parallel is limited. This is also advantageous.

(Embodiment 3)
FIG. 7 shows a configuration of a power source-separated LED lighting apparatus using the LED lighting device according to the first or second embodiment. The instrument housing 7 is made of a metal cylinder that is open at the lower end, and the open end of the lower end is covered with a light diffusion plate 8. The LED light emission part 2 is arrange | positioned so that this light-diffusion plate 8 may be opposed. Reference numeral 21 denotes an LED mounting board on which the LEDs 2a to 2d of the LED light emitting unit 2 are mounted. The appliance housing 7 is embedded in the ceiling 9 and wired from the DC power supply unit 4 arranged on the back of the ceiling via the lead wire 5 and the connector 6.

(Embodiment 4)
FIG. 8 shows a configuration of a power supply built-in LED lighting apparatus using the LED lighting device of the first or second embodiment. Reference numeral 21 denotes an LED mounting board on which the LEDs 2a to 2d of the LED light emitting unit 2 are mounted. Reference numeral 41 denotes a power circuit board on which electronic components of the DC power supply unit 4 shown in FIG. 2 or 4 are mounted. The LED light emission part 2 is installed so that it may contact the heat sink 71 in the instrument housing | casing 7, and the heat | fever which LED2a-2d generate | occur | produces is released to the instrument housing | casing 7. FIG. Further, the LED light emitting unit 2 and the DC power supply unit 4 are connected by a lead wire 5 through a hole provided in the heat radiating plate 71. The heat dissipation plate 71 is a metal plate such as an aluminum plate or a copper plate, and has both a heat dissipation effect and a shielding effect. The heat radiating plate 71 is electrically connected to the instrument housing 7 and grounded, but is a non-charging portion that is electrically separated from the plus side and the minus side of the lead wire 5.

  As described above, since the lighting device is built in the fixture housing 7, the wiring to the LED light emitting unit 2 is not touched from the outside, so that the routing of the wiring becomes constant and the noise performance is stabilized.

It is a block circuit diagram which shows the basic composition of this invention. It is a circuit diagram which shows the structure of Embodiment 1 of this invention. It is an operation | movement waveform diagram of Embodiment 1 of this invention. It is a circuit diagram which shows the structure of Embodiment 2 of this invention. It is an operation | movement waveform diagram of Embodiment 2 of this invention. It is explanatory drawing which shows the relationship between the ripple rate and DC light beam ratio of Embodiment 2 of this invention. It is sectional drawing which shows the mounting state of Embodiment 3 of this invention. It is sectional drawing which shows the mounting state of Embodiment 4 of this invention. It is a circuit diagram of a conventional example. It is an operation | movement waveform diagram of a prior art example. It is a characteristic view of the constant current element used for a prior art example.

Explanation of symbols

Vs Commercial AC power supply DB Full wave rectifier C1 First capacitor C2 Second capacitor 1 Switching power supply circuit unit 2 LED light emitting unit 3 Filter circuit unit

Claims (6)

A full-wave rectifier for full-wave rectification of a commercial AC power supply, a first capacitor connected in parallel to the output end of the full-wave rectifier, a switching power supply circuit section having an input end connected in parallel to the first capacitor, and a switching power supply An LED light-emitting unit connected to the output end of the circuit unit and a second capacitor connected in parallel to the LED light-emitting unit, wherein the first capacitor has a capacitance of less than 1 μF, and the second capacitor is an LED light-emitting unit The LED lighting device is characterized in that the ripple rate of the current flowing through the capacitor is set to a capacity of less than 1. The LED lighting device according to claim 1, wherein the switching power supply circuit unit is a flyback power supply circuit. The LED lighting device according to claim 1, wherein the switching power supply circuit unit is a step-down chopper circuit. The LED lighting device according to claim 1, further comprising a filter circuit unit at an AC input terminal of the full-wave rectifier. The LED lighting device according to any one of claims 1 to 4, wherein the power consumption of the LED light emitting unit is 20 W or less. The LED lighting fixture which incorporated the LED lighting device in any one of Claims 1-5.

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