JP2015056271A - Power circuit for led lighting unit and led lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power circuit for an LED lighting unit, capable of suppressing a noise terminal voltage resulting from conduction noise while suppressing an inrush current resulting from a transient response.SOLUTION: A power circuit for an LED lighting unit includes an input filter circuit connected with a commercial power supply, and a DC supply circuit which converts AC output from the input filter circuit into DC and supplies the converted DC to an LED lighting unit. The input filter circuit includes a normal mode filter and a common mode filter.

Description

  The present invention relates to an LED illumination unit power circuit that drives an LED illumination unit that uses a light-emitting diode (LED) as a light source, and an LED illumination device that includes such an LED illumination unit power circuit.

With the widespread use of LED lighting devices, it is necessary to develop power supply circuits for LED lighting units. In developing a power supply circuit for an LED lighting unit, in order to reduce the burden and influence on the insulation performance of the switchboard, it is necessary to suppress the inrush current generated due to the capacity component of the power supply circuit during an excessive response. . Further, in the LED lighting unit power supply circuit, in addition to suppressing inrush current, it is necessary to reduce conduction noise in order to prevent flickering of LED lighting.
In order to suppress the inrush current and reduce the conduction noise in this way, a power supply device for an LED lamp for illumination that includes an inrush current limiting circuit and a noise removal circuit has been proposed (for example, see Patent Document 1).
The power supply device for the LED lamp for illumination described in Patent Document 1 includes an inrush current limiting circuit in which a coil and a resistor are connected in parallel, and a noise removal circuit in which a common mode choke coil and a capacitor are connected.

JP 2010-277819 A (paragraphs [0026], [0027] and FIG. 1)

In the LED lighting unit power supply circuit, when the inrush current is suppressed and the conduction noise is reduced, the following problem occurs, and the solution thereof is necessary.
That is, the inrush current value of the power supply circuit is determined by the impedance value of the circuit. Therefore, when the impedance value is increased, the inrush current value is also limited.
However, increasing the impedance value also limits the flow of alternating current. Further, when the resistance value is increased, a problem of heat generation occurs. On the other hand, when the inductance value is increased, the current waveform is distorted.
In order to reduce the voltage fluctuation after rectification, it is effective to increase the capacitance of the input side smoothing capacitor connected to the input side. However, the inrush current generated in the power supply circuit increases according to the capacitance of the input side smoothing capacitor connected to the input side.

  Increasing the inductance value of the common mode choke coil increases the effect of suppressing the noise terminal voltage (conduction noise) in the low frequency band, while reducing the inductance value reduces the noise terminal voltage (conduction noise) in the high frequency band. The suppression effect becomes larger. Thus, the effect of suppressing the noise terminal voltage has frequency dependence due to the inductance value of the common mode choke coil.

  Thus, the impedance value, the capacitance value, and the resistance value of the LED lighting unit power supply circuit are matched to greatly reduce the inrush current of the LED lighting unit power supply circuit and the noise terminal voltage (conduction noise). It has been difficult to do so far.

  An object of the present invention is to provide a power circuit for an LED lighting unit and an LED lighting device capable of reducing a noise terminal voltage caused by conduction noise while suppressing an inrush current caused by an excessive response. .

In order to achieve the above-mentioned proposal, a power circuit for an LED lighting unit according to the present invention includes:
An input filter circuit connected to a commercial power source;
A direct current supply circuit that converts alternating current output from the input filter circuit into direct current, and supplies the converted direct current to the LED lighting unit;
With
The input filter circuit includes a normal mode filter and a common mode filter.

  The LED lighting unit power supply circuit according to the present invention includes both the normal mode filter and the common mode filter, thereby reducing both the inrush current due to the capacity of the power supply circuit and the noise terminal voltage due to the conduction noise. Is possible.

The LED lighting unit power circuit according to the present invention includes a pair of normal mode choke coils connected to the pair of terminals of the commercial power source, and a pair of output lines output from the normal mode choke coils. A first capacitor connected in between,
A common mode choke coil connected between a pair of output lines output from the normal mode choke coil; a line bypass capacitor connected between a pair of output lines output from the normal mode choke coil; And a second capacitor connected between a pair of output lines output from the common mode choke coil.
In the LED lighting unit power circuit according to the present invention, the normal mode filter and the common mode filter have such a configuration, so that both the inrush current caused by the capacity of the power circuit and the noise terminal voltage caused by the conduction noise can be obtained. It becomes possible to reduce.

The LED illumination unit power circuit according to the present invention may be characterized in that the normal mode filter and the common mode filter are arranged in the order of the normal mode filter and the common mode filter from the commercial power supply side.
The LED lighting unit power supply circuit according to the present invention includes both the normal mode filter and the common mode filter, thereby reducing both the inrush current due to the capacity of the power supply circuit and the noise terminal voltage due to the conduction noise. In particular, by disposing the normal mode filter and the common mode filter in this order, it is possible to suppress excessive current and particularly reduce inrush current.

The LED illumination unit power circuit according to the present invention may be characterized in that the normal mode filter and the common mode filter have different inductance values.
In the LED lighting unit power supply circuit according to the present invention, when the inductance is set to a different value, the noise terminal voltage can be reduced in both the low frequency band and the high frequency band, and conduction noise can be suppressed.

The LED lighting device according to the present invention includes the above-described power circuit for the LED lighting unit.
In the LED lighting device according to the present invention, the power circuit for the LED lighting unit includes both the normal mode filter and the common mode filter, so that the inrush current due to the capacity of the power circuit and the noise terminal voltage due to the conduction noise are reduced. Both can be reduced.

The LED lighting device according to the present invention may include a plurality of the LED lighting unit power supply circuits described above.
The LED lighting device according to the present invention includes a plurality of the LED lighting unit power supply circuits described above and is connected and driven, thereby achieving high output while suppressing inrush current.

The LED lighting device according to the present invention includes a plurality of the power circuits for the LED lighting unit described above,
Each of the direct current supply circuits includes a switch for supplying a direct current to the LED lighting unit,
A direct current may be supplied to the LED lighting unit by controlling the operation timing of each of the switches.
The LED lighting device according to the present invention controls the operation timing of the switches included in each of the LED lighting unit power supply circuits when connecting and driving the plurality of LED lighting unit power supply circuits described above, thereby reducing the inrush current. It is possible to increase the output while suppressing the peak value.

The LED lighting unit power supply circuit and the LED lighting device according to the present invention include both the normal mode filter and the common mode filter in the input filter circuit as described above, so that inrush current and conduction noise caused by the capacity of the power supply circuit are provided. It is possible to reduce both of the noise terminal voltages caused by.
That is, in the LED lighting unit power supply circuit and the LED lighting device according to the present invention, the demand on the insulation performance of the LED lighting unit power supply circuit and the LED lighting device is reduced by suppressing the inrush current due to the capacity of the power supply circuit. At the same time, it is possible to reduce the flickering of the LED illumination by reducing the noise terminal voltage caused by the conduction noise.

It is an equivalent circuit schematic of the LED lighting apparatus which concerns on the 1st Embodiment of this invention. (A) is a graph which shows the measurement result of the inrush current in the power circuit for LED lighting units according to the first embodiment on the time axis of 20 μS / div, and (b) is for the LED lighting unit according to the comparative example. It is a graph which shows the measurement result of the inrush current in a power circuit on the time axis of 20 μS / div. (A) is a graph which shows the measurement result of the noise terminal voltage of 9 kHz-150 kHz frequency band in the power supply circuit for LED lighting units concerning a 1st embodiment, and is for LED lighting units concerning a 1st embodiment. It is a graph which shows the measurement result of the noise terminal voltage of 150kHz-30MHz frequency band in a power circuit, (c) is the measurement result of the noise terminal voltage of 9kHz-150kHz frequency band in the power circuit for LED lighting units concerning a comparative example. (D) is a graph which shows the measurement result of the noise terminal voltage of 150 kHz-30 MHz frequency band in the power supply circuit for LED lighting units which concerns on a comparative example. (A) is a top view which shows the state which has arrange | positioned the circuit component which comprises the power supply circuit for LED lighting units which concerns on 1st Embodiment on the circuit board from the surface of a circuit board, (b) is this circuit component It is a back view which shows the state which has arrange | positioned in the circuit board from the back surface of a circuit board. It is explanatory drawing which shows a response | compatibility with the top view of Fig.4 (a), and each circuit component which comprises the power supply circuit for LED lighting units which concerns on 1st Embodiment. It is an equivalent circuit schematic of the LED lighting apparatus which concerns on the 2nd Embodiment of this invention.

[First Embodiment]
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an equivalent circuit diagram of an LED lighting device 1 according to an embodiment of the present invention. The LED lighting apparatus 1 includes an LED, an LED lighting unit 2 that emits LED light by applying a direct current to the LED, and is connected to a commercial AC power source, converts the alternating current into a direct current, and converts the direct current into the LED lighting unit 2. And an LED lighting unit power supply circuit 3 for supplying to the LED.

The LED lighting unit power supply circuit 3 is connected to a commercial power supply, and includes an input filter circuit 31 for suppressing an inrush current caused by an excessive phenomenon and reducing a noise terminal voltage caused by conduction noise. A DC current supply circuit 36 that converts the output AC current into DC current and supplies the converted DC current to the LED lighting unit 2 is provided.
The LED illumination unit power supply circuit 3 according to the first embodiment will be described in more detail in order from the AC power supply side.

  The input filter circuit 31 is connected to an AC power source through a circuit protection fuse F1. The input filter circuit 31 includes a normal mode filter 32 and a common mode filter 33. That is, in the LED lighting unit power circuit 3 according to the first embodiment, the input filter circuit 31 includes a normal mode filter 32 for suppressing normal mode noise generated in a closed circuit in the power circuit, a power circuit, Both are provided with a common mode filter 33 for suppressing common mode noise generated between the ground via the stray capacitance. In the first embodiment, since the input filter circuit 31 includes both the normal mode filter 32 and the common mode filter 33, by selecting and determining the inductance value, the capacitance value, and the resistance value of the circuit, when the power is turned on, It is possible to suppress both the generated inrush current and the noise terminal voltage due to conduction noise.

In the LED lighting unit power supply circuit 3 according to the first embodiment shown in FIG. 1, the normal mode filter 32 includes a pair of normal mode choke coils L1 and L2 connected to a pair of terminals of a commercial power supply, and a normal mode. And a smoothing first capacitor C1 connected between a pair of output lines output from the choke coils L1 and L2.
The common mode filter 33 includes a common mode choke coil L3 connected between a pair of output lines output from the normal mode choke coils L1 and L2, and a pair of output lines output from the normal mode choke coils L1 and L2. Line bypass capacitors C3 and C4 to be connected and a second capacitor C2 for smoothing connected between a pair of output lines output from the common mode choke coil L3.

  Line bypass capacitors C3 and C4 are also referred to as Y-con. The line bypass capacitor is used by connecting the connection portion between the capacitors C3 and C4 to the ground. The line bypass capacitors C3 and C4 have an effect of suppressing common mode noise. On the other hand, the first capacitor C1 and the second capacitor C2 used for smoothing have an effect of suppressing normal mode noise.

  The normal mode choke coils L1 and L2 and the common mode choke coil L3 may have different inductance values. Since the normal mode choke coil and the common mode choke coil have different inductance values, it is possible to reduce the noise terminal voltage in both the low frequency band and the high frequency band.

  In the LED lighting unit power supply circuit 3 according to the first embodiment of the present invention, the direct current supply circuit 36 includes, for example, a bridge diode 37 that rectifies an alternating current into a direct current. The direct current supply circuit 36 may include a switching element 38 and a switching transformer 39 for turning on and off the supply of direct current to the LED lighting unit 2. The direct current supply circuit may include a configuration that converts the alternating current output from the input filter circuit into a direct current and supplies the converted direct current to the LED lighting unit, and is not limited to the above configuration.

  The LED lighting unit power supply circuit 3 according to the first embodiment may include varistors ZNR1 and ZNR2 for protecting the circuit against a high voltage. The LED lighting unit power supply circuit 3 according to the first embodiment may include a temperature compensation thermistor TH1.

  The measurement result of the inrush current and the noise terminal voltage in the power circuit for the LED lighting unit according to the first embodiment of the present invention is compared with the measurement result of the inrush current and the noise terminal voltage in the power circuit for the LED lighting unit according to the comparative example. And describe.

Prior to the description of the measurement results, the configurations of the LED lighting unit power circuit according to the first embodiment and the LED lighting unit power circuit according to the comparative example will be described.
The input filter circuit of the LED illumination unit power supply circuit according to the first embodiment includes both the normal mode filter and the common mode filter as described above.
On the other hand, the LED lighting unit power circuit according to the comparative example is invented to suppress the inrush current and the noise terminal voltage in the middle of conceiving the LED lighting unit power circuit according to the first embodiment. It was examined by the person. The power circuit for the LED lighting unit according to the comparative example includes two common mode filters having different inductance values. The reason why the inductance values of the two common mode filters are different from each other is to suppress the noise terminal voltage in both the low frequency band and the high frequency band.

The measurement result of the inrush current will be described with reference to FIG.
The graph of FIG. 2A shows the measurement result of the inrush current in the LED lighting unit power supply circuit according to the first embodiment of the present invention, and the graph of FIG. 2B shows the LED according to the comparative example. The measurement result of the inrush current in the power supply circuit for lighting units is shown. These measurements were performed by connecting an LED as a load under the conditions of an input voltage of 100 V, an input voltage frequency of 50 Hz, an ambient temperature of 27.4 ° C., and an ambient humidity of 53.0%. 2A and 2B, the vertical axis of the upper input voltage waveform is 200 V / div, the vertical axis of the lower input current is 2 A / div, and the time on the horizontal axis is 20 μs / div. From FIG. 2A, the peak value of the inrush current in the power circuit for the LED lighting unit according to the first embodiment of the present invention is 1.36A. On the other hand, from FIG. 2B, the peak value of the inrush current in the power circuit for the LED lighting unit according to the comparative example is 6.40A. From this, it can be seen that in the embodiment of the present invention, the value of the inrush current is significantly lower than that of the comparative example.

The measurement result of the noise terminal voltage caused by the conduction noise will be described below with reference to FIG.
The graph of Fig.3 (a) shows the measurement result of the noise terminal voltage of 9 kHz-150 kHz frequency band in the power supply circuit for LED lighting units according to the first embodiment of the present invention, and the graph of Fig.3 (b) The measurement result of the noise terminal voltage of 150 kHz-30 MHz frequency band in the power supply circuit for LED lighting units which concerns on 1st Embodiment is shown. Moreover, the graph of FIG.3 (c) shows the measurement result of the noise terminal voltage of 9 kHz-150kHz frequency band in the power supply circuit for LED lighting units concerning a comparative example, and the graph of FIG.3 (d) concerns on a comparative example. It is a graph which shows the measurement result of the noise terminal voltage of 150kHz-30MHz frequency band in the power supply circuit for LED lighting units. FIG. 3A and FIG. 3B showing the noise terminal voltage in the power circuit for the LED lighting unit according to the embodiment of the present invention, and the graphs of FIG. 3C and FIG. 3D relating to the comparative example. Is compared over the entire frequency band of 9 kHz to 30 MHz, in the LED lighting unit power supply circuit according to the first embodiment of the present invention, the noise terminal voltage is significantly reduced compared to the noise terminal voltage in the comparative example. I understand that.

  The QP limit value is described for reference in each graph showing the noise terminal voltage in FIGS. 3 (a) to 3 (d). The QP limit value indicates a permissible value of the radio interference characteristics of electric lighting and similar devices defined in the standard Cispr15. The QP limit value does not display only one point of the leader line, but the values on the continuous line become the QP limit value corresponding to the value of each frequency. Each noise terminal voltage value is lower than the QP limit value.

The LED lighting unit power supply circuit and the LED lighting device according to the first embodiment are generated in the case of an excessive response due to the capacity of the power supply circuit by providing both the normal mode filter and the common mode filter in the input filter circuit. It is possible to reduce both the inrush current and the noise terminal voltage due to conduction noise.
That is, in the LED illumination unit power supply circuit and the LED illumination device according to the first embodiment, by providing both the normal mode filter and the common mode filter, the inrush current is greatly reduced and the LED illumination flicker is small. It becomes possible to suppress conduction noise to a certain extent.

  As described above, in the LED lighting unit power supply circuit and the LED lighting device according to the first embodiment, the inrush current is greatly reduced, thereby reducing the requirements regarding the insulation performance of the switchboard, making the switchboard compact and low cost. And the reliability of the switchboard can be improved. Further, by suppressing the conduction voltage, it is possible to prevent flickering of the LED lighting and to stabilize the LED lighting. That is, in the first embodiment, it is possible to reduce the inrush current and suppress the conduction voltage, thereby making the switchboard compact and stabilizing the LED illumination.

The reason why the effect of reducing the inrush current is increased by adding the normal mode filter is that the impedance of the normal mode choke coil reduces the inrush current.
The advantages of adding the normal mode filter and the advantages of arranging the normal mode filter on the power supply side from the common mode filter will be described in more detail below.

In the conventional general configuration, a capacitor, a common mode filter including a coil, a capacitor, and a common mode filter including a coil are arranged in this order from the power supply side.
On the other hand, in the configuration of the embodiment of the present invention, the normal mode filter including the coil, the capacitor, the common mode filter including the coil, and the capacitor are arranged in this order from the power supply side.

First, the advantage that the filter including the coil is arranged on the power supply side from the capacitor will be described.
In the conventional general configuration, since the capacitor is charged when the power is turned on, the transient current increases.
On the other hand, in the configuration of the present embodiment, an increase in the current flowing toward the capacitor can be suppressed and the current can flow slowly through the coil included in the filter. Thereby, a transient current is suppressed.

Next, the reason why the filter disposed on the power supply side is a normal mode filter will be described below.
The common mode coil has a low impedance when an AC voltage is applied. On the other hand, the normal mode coil has high impedance when an AC voltage is applied. Therefore, if a normal mode coil is arranged on the power supply side, the effect of suppressing the transient current is enhanced.

  In the first embodiment of the present invention, the inductance of the normal mode choke coil and the inductance of the common mode choke coil may be set to different values. When the inductance of the normal mode choke coil and the inductance of the common mode choke coil are set to different values, it is possible to reduce the noise terminal voltage in both the low frequency band and the high frequency band and suppress conduction noise.

  FIG. 4A shows a state in which circuit components constituting the power circuit for the LED lighting unit according to the first embodiment are arranged on the circuit board 40 from the surface of the circuit board 40. FIG. 4B shows a state in which the circuit components are arranged on the circuit board 40 from the back surface of the circuit board 40.

FIG. 5 shows how each circuit component constituting the power circuit for the LED lighting unit according to the first embodiment is arranged on the circuit board 40.
In the circuit board 40 shown in FIG. 5, relatively large components such as normal mode choke coils L1 and L2, common mode choke coil L3, bridge diode 37, switching element 38, and switching transformer 39 are optimally arranged. Between these large components, capacitors C1 to C5, varistors ZNR1 and ZNR2, etc. are arranged in a compact manner. As described above, in the LED illumination unit power supply circuit according to the first embodiment, it can be seen that each circuit component is compactly and efficiently arranged on the circuit board 40.

[Second Embodiment]
FIG. 6 shows an equivalent circuit diagram of the LED lighting apparatus 101 according to the second embodiment of the present invention. The LED lighting apparatus 101 according to the second embodiment connects a plurality of LED lighting unit power supply circuits 3A and 3B according to the first embodiment, and connects and drives the connected LED lighting unit power supply circuits 3A and 3B. Thus, a direct current is supplied to the LED lighting unit 103 to operate as the lighting device. In the LED lighting device 101 according to the second embodiment, the LED lighting unit power circuit 103 is connected and driven by connecting a plurality of LED lighting unit power circuits 3A and 3B according to the first embodiment, It corresponds to the high output of the LED lighting unit.

  In the LED lighting device 101 according to the second embodiment, the LED lighting unit power supply circuits 3A and 3B have input filter circuits 31A and 31B, respectively, and the input filter circuits 31A and 31B each have a normal mode filter 32A. , 32B and common mode filters 33A, 33B. Similarly to the LED illumination unit power supply circuit according to the first embodiment, the LED illumination unit power supply circuits 3A and 3B of the LED illumination device 101 according to the second embodiment are respectively common with the normal mode filters 32A and 32B. Since both of the mode filters 33A and 33B are provided, it is possible to reduce both the inrush current generated during the excessive response due to the capacity of the power supply circuit and the noise terminal voltage due to the conduction noise.

Generally, when a plurality of LED lighting unit power supply circuits are connected to form a single high-power LED lighting unit power supply circuit, each LED lighting unit power supply circuit is considered as a whole LED lighting unit power supply circuit. The inrush current is added to increase the inrush current.
However, in each of the plurality of LED lighting unit power supply circuits 3A and 3B according to the second embodiment, the inrush current is reduced as in the first embodiment. Therefore, the LED according to the second embodiment is reduced. In the lighting unit power supply circuit 103, even if the plurality of LED lighting unit power supply circuits 3A and 3B are connected and driven, the amount of increase of the inrush current can be suppressed to a certain value or less.

  Further, in the LED lighting device 101 according to the second embodiment shown in FIG. 6, each of the LED lighting unit power supply circuits 3 </ b> A and 3 </ b> B to be connected supplies a switch 38 </ b> A for supplying a direct current to the LED lighting unit 102. 38B may be provided. By operating the switches 38A and 38B while shifting the on / off timing, the peak value of the inrush current can be further suppressed.

  As described above, the LED lighting apparatus according to the second embodiment has been described with respect to the case where two LED lighting unit power supply circuits are connected and connected. It is not limited to.

1, 101 LED illumination device 2, 102 LED illumination unit 3, 3A, 3B, 103 LED illumination unit power supply circuit 31, 31A, 31B Input filter circuit 32, 32A, 32B Normal mode filter 33, 33A, 33B Common mode filter 36 , 36A, 36B DC current supply circuit 37, 37A, 37B Bridge diode 38, 38A, 38B Switching element 39, 39A, 39B Switching transformer 40 Circuit board L1 Normal mode choke coil L2 Normal mode choke coil L3 Common mode choke coil L4 Choke coil C1 Capacitor C2 Capacitor C3 Capacitor C4 Capacitor C5 Capacitor TH1 Thermistor ZNR1 Varistor ZNR2 Varistor F1 Fuse

Claims (7)

An input filter circuit connected to a commercial power source;
A direct current supply circuit that converts alternating current output from the input filter circuit into direct current, and supplies the converted direct current to the LED lighting unit;
With
The power supply circuit for an LED illumination unit, wherein the input filter circuit includes a normal mode filter and a common mode filter. The normal mode filter has a pair of normal mode choke coils respectively connected to a pair of terminals of the commercial power supply, and a first capacitor connected between a pair of output lines output from the normal mode choke coils. And
A common mode choke coil connected between a pair of output lines output from the normal mode choke coil; a line bypass capacitor connected between a pair of output lines output from the normal mode choke coil; The LED lighting unit power supply circuit according to claim 1, further comprising: a second capacitor connected between a pair of output lines output from the common mode choke coil.   3. The LED lighting unit power circuit according to claim 1, wherein the normal mode filter and the common mode filter are arranged in the order of the normal mode filter and the common mode filter from the commercial power source side. .   The power circuit for an LED lighting unit according to any one of claims 1 to 3, wherein the normal mode filter and the common mode filter have different inductance values.   An LED lighting device comprising the power circuit for an LED lighting unit according to claim 1.   An LED lighting apparatus comprising a plurality of LED lighting unit power supply circuits according to claim 1. A plurality of LED lighting unit power supply circuits according to any one of claims 1 to 4,
Each of the direct current supply circuits includes a switch for supplying a direct current to the LED lighting unit,
An LED lighting device, wherein a direct current is supplied to the LED lighting unit by controlling an operation timing of each of the switches.

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