JP4370901B2 - LED lighting device - Google Patents

Description

  The present invention relates to an LED lighting device that lights an LED using an AC power source.

  In recent years, with the commercialization of blue LEDs, white high-intensity LEDs have been developed by combining blue LEDs and yellow phosphors, mixing RGB LEDs, etc., and LEDs that have been used mainly for display purposes in the past There is a movement to use for lighting applications. Recently, means to increase the light output as a total by increasing the number of LEDs while increasing the number of LEDs while efficiently dissipating the white LED, and a road signal light, a warning signal light for a train crossing, spot It has already been developed for lighting and the like (see Patent Document 1).

  Since the LED is a current-driven semiconductor element, it is necessary to pass a predetermined current through the LED when the LED is lit. In general, the ON voltage of a blue LED is about 3.5V. For example, when a rated current of 20 mA is supplied to the LED with a DC power supply of 5V, the resistance element R = (5-3.5) /0.02=75 ohms Must be connected in series with the LED.

  In addition, when a plurality of LEDs are connected in series, a DC power source that is equal to or higher than the voltage obtained by multiplying the number of connected LEDs by the LED ON voltage Vf is required, and the impedance obtained by the same calculation as described above is connected. Therefore, it is necessary to match the current flowing through the LED with the rated current.

  However, the LED element has a large variation in the ON voltage Vf, and usually has a voltage range of about ± 10% with respect to 3.5V. In the above example, since the LED current varies greatly from the rated current due to the variation of the ON voltage Vf, the fluctuation of the LED temperature rise is large, greatly affecting the life of the LED.

  Therefore, considering the variation of the ON voltage Vf, the rated current is not allowed to flow, and considering the lower limit condition of the ON voltage Vf variation, the current limiting resistance value is increased to set a smaller current, or the LED current exceeds a certain level. The circuit configuration is such that a constant current that does not increase flows, so that the temperature of the LED is reduced and the lifetime is ensured.

  In general, since a DC voltage is required to light one LED or a plurality of LED modules, a commercially available DC power supply device, battery means, or the like is used. Also, in lighting fixtures that are powered directly from an AC power source, such as stand lighting, nightlights, and footlamps that use a plurality of LEDs arranged side by side, a rectifier is provided inside the lighting fixture, and if necessary, smoothing means, current limiting means, and control circuit means are configured. Then, the LED element is lit by passing a current.

  Since it is generally recognized that LEDs have a long life, there is no need to replace the LED when it is not lit at the end of its life. Is integrally formed inside the instrument.

  2. Description of the Related Art In recent years, LED modules (LED mounting board portions) configured with a plurality of LEDs have been commercialized as light source applications from LED element manufacturers and set manufacturers. When these products are purchased and lighting devices and lighting fixtures are configured, a means for adopting the above-described DC power supply device that can freely set the DC power supply voltage from several volts to several tens of volts in the lighting circuit section is common. However, DC power supply devices generally have a constant voltage output with a standard voltage set such as 12 V or 24 V, and an LED lighting circuit unit that controls the LED element or LED mounting substrate unit to control the constant current is necessary. It becomes.

  An example of the conventional circuit configuration is shown in FIG. In this example, in order to turn on the LED mounting board part 3, two circuit parts of the DC power supply device 2a and the LED lighting circuit 2b must be formed in the lighting device and the lighting fixture.

  Moreover, the example which comprises the LED lighting circuit in the LED mounting board | substrate part, and comprises the lighting fixture combining with a commercially available DC power supply device is shown in FIG. In this example, a constant current circuit is mounted on the LED mounting board portion 3a, and a rated current can be passed through the LED by connecting a DC voltage. Therefore, a commercially available power supply device (for example, as shown in FIG. 9). Since it can be easily combined with a battery with a constant voltage output type DC power source), it is adopted as an effective means.

  However, since the LED mounting substrate portion 3a (which incorporates the constant current circuit element) requires LED constant current circuits (resistors R1 to R6 and transistors Q1 to Q5) as shown in FIG. The board part of the LED module part 3a is increased in size, the number of parts is increased, and the cost is increased, and there is a possibility that the purpose of reducing the size and thickness of the light source part, which is a feature of the light source using LEDs, cannot be achieved.

In addition, when a large current is applied to the LED on the LED mounting board part or a plurality of LEDs are mounted at a high density, and the heat generation of the LED part rises, an aluminum plate or a copper plate is placed on the back side of the LED mounting board part. There is a problem that when a heat dissipation structure is applied by sticking, it is not possible to secure a place for mounting circuit components other than LED elements on the LED mounting surface.
JP 2003-30785 A

  In view of the above problems, the present invention is directed to a lighting device and a lighting fixture having an LED module unit that uses an LED element or a plurality of LED elements as one light source. The DC power supply that supplies the DC output by receiving commercial AC power supply, with the aim of increasing the light output by thinning, miniaturization, and high output by adopting the heat dissipation structure, which are the features of LED lighting By providing the device with a constant current function, two circuit configurations of a constant voltage DC power supply device and a constant current function are not required, and the specifications of the LED module are, for example, a plurality of 12V LED modules and 24V LED modules. The present invention proposes an LED lighting device capable of handling an LED module with a single constant current power supply device.

According to the present invention, in order to solve the above problems, as shown in FIG. 11 or FIG. 13 , a DC power supply device 2 that receives an AC power supply 1 and outputs a DC voltage, and receives the DC voltage and lights up. The LED lighting device is composed of an LED module unit 3 on which the LED element to be mounted is mounted. The LED element is composed of one or a plurality of LED elements, and the DC power supply device 2 rectifies the AC power supply 1. As shown in FIG. 14, a switching element (output terminal of the IPD control circuit 23) connected in series to the output of the rectifying means DB, and a primary winding to the output of the rectifying means DB via the switching element. , A rectifying / smoothing means (D1, C1) connected to the secondary winding of the transformer T1, and a current detection for detecting a current output from the rectifying / smoothing means to the LED module unit 3. One-stone forward comprising means 22 and a control circuit (control terminal of IPD control circuit 23) that controls the ON / OFF of the switching element so that the output current is substantially constant in response to the detection output of current detection means 22 Type switching power supply circuit, in which a switching element Q is provided in series at the output end of the DC power supply device 2 or the LED module unit 1, and the switching element Q is intermittently driven to be turned on and off at a high frequency so as not to flicker. 12 (timer circuit in FIG. 12) and dimming means (resistors R1, R2 in FIG. 12) that change the effective current flowing in the LED element by changing the ON / OFF ratio of the switch element Q. ) Is provided .

  According to the present invention, by providing a constant current function to a direct current power supply device that receives an alternating current power supply and supplies a direct current output, two circuit configurations of a constant voltage direct current power supply device and a constant current function are not necessary, Since the LED module part, which is the light source, only needs to be mounted with LED elements and the minimum number of members, the light output is reduced by thinning, downsizing, and high output by adopting a heat dissipation structure, which are the characteristics of lighting devices using LEDs. In addition, there is an effect that a single constant current power supply device can cope with a plurality of LED modules having different specifications. In addition, by controlling the LED module at a constant current, it is possible to prevent the LED current from changing due to variations in the on-voltage of the LED element, etc. It has the effect of suppressing and preventing shortening of the tool life due to light degradation of the LED.

According to the first to sixth aspects of the present invention, the switch element is connected between the DC power supply device and the LED module unit, and the effective current of the LED module unit is variably controlled by ON / OFF control of the switch element. Dimming control can be performed.
According to the first and second aspects of the present invention, since the switching power supply type constant current power supply device is used as the DC power supply device, the non-switching power supply type constant current power supply device as in the conventional example of FIG. 10 is used. In comparison, there is an effect that the amount of heat generated by the power supply device is small and the luminous efficiency of the lighting fixture is increased.

According to the invention of claim 2 , since the chopper type DC power supply device is used, distortion of the input current from the commercial AC power supply can be reduced as compared with the case of using the conventional capacitor input type DC power supply device. At the same time, it is possible to eliminate the pause period of the input current, so that the input power factor can be improved. In particular, when a step-down chopper type DC power supply is used, when the total drive voltage of the LED module is lower than the commercial power supply voltage, a non-switching power supply type constant current power supply as in the conventional example of FIG. Compared to the case of using the device, there is a particularly excellent effect that the circuit efficiency is greatly improved.

(Prerequisite basic configuration)
FIG. 1 shows a basic circuit configuration as a premise of the present invention. The AC power source 1 is rectified by the rectifier bridge DB, receives the DC voltage, and constitutes a constant current power source circuit 20 using the DC voltage conversion circuit 21 and the current detection means 22. The rectifier bridge DB and the constant current power supply circuit 20 constitute a constant current DC power supply device 2. This constant current direct current power supply device 2 is a lighting device and a lighting fixture main body, and a lighting device and a LED lighting fixture can be configured by incorporating an LED lighting portion on which the LED module portion 3 (LED mounting substrate portion) is mounted.

If it is the structure of this invention, the LED module part has the characteristic which can light a some LED module part with one lighting apparatus and a lighting fixture, without being influenced by the voltage decided by LED connection number. Moreover, the LED module part can be made thinner and smaller by separately configuring the lighting device and the lighting fixture so that the characteristics of the light source using the LED can be fully utilized.
In the following configurations 1 to 5 , the constant current power supply circuit 20 will be described with a specific circuit configuration example .

(Prerequisite configuration 1)
FIG. 2 shows a configuration of the constant current power supply circuit 20 in the configuration 1 which is a premise of the present invention. In this example , a one-stone forward type DC-DC converter circuit employing the IPD control circuit 23 is used as the constant current power supply circuit 20. Here, the IPD (intelligent power device: made by Matsushita) is an integrated switching element and its control circuit, and the output terminal is connected so that the voltage of the control terminal as a feedback input terminal is substantially constant. This is a power element for a switching power supply that can control ON / OFF of the power supply.

  The smoothing capacitor C0 corresponds to the capacitor C0 of FIG. 1 and is charged with a DC voltage obtained by full-wave rectifying the commercial AC power supply 1 with the rectification bridge DB. An IPD control circuit 23 is connected to the positive electrode of the capacitor C0 via the primary winding of the transformer T1. A capacitor C1 is connected to the output winding provided on the secondary side of the transformer T1 via a diode D1. A capacitor C2 is connected to the detection winding provided on the secondary side of the transformer T1 via a diode D2. The capacitor C2 is connected to the control terminal of the IPD control circuit 23 through the light receiving element of the photocoupler PC. An output terminal is connected to the capacitor C1 through a resistor R1. A series circuit of the resistor R2, the light emitting element of the photocoupler PC, and the Zener diode ZD3 is connected in parallel to both ends of the resistor R1. The resistors R1 and R2, the Zener diode ZD3, and the photocoupler PC constitute current detection means 22, and detects the current output from the capacitor C1 to the LED module unit 3 in FIG. 1 via the output terminal. The IPD control circuit 23 controls ON / OFF of the current flowing through the primary winding of the transformer T1 so that the current detected by the current detection means 22 is substantially constant. An anti-series circuit of Zener diodes ZD1 and ZD2 for preventing overvoltage is connected in parallel to both ends of the primary winding of the transformer T1.

Thus, in this example , the constant current power supply circuit is configured by a one-stone forward type circuit, and the detection winding provided on the secondary side of the transformer T1 and the current detection means 22 provided on the output terminal. The feedback signal detected in (1) is input to the control terminal of the IPD control circuit 23 to constitute a constant current drive control circuit .

(Assumption 2)
FIG. 3 shows a configuration of the constant current power supply circuit 20 in the configuration 2 which is a premise of the present invention. In this example , a step-down converter circuit employing the above-described IPD control circuit 23 is used as the constant current power supply circuit 20. Although the IPD control circuit 23 is used in the same manner as in the first configuration , in this example , a non-insulated circuit configuration is adopted for the feedback circuit. That is, in the presupposed configuration 1 , voltage feedback is applied to the control terminal of the IPD control circuit 23. In this example , the current flowing through the detection resistor R2 is converted into voltage and fed back to the control terminal of the IPD control circuit 23. Yes.

The smoothing capacitor C0 corresponds to the capacitor C0 of FIG. 1 and is charged with a DC voltage obtained by full-wave rectifying the commercial AC power supply 1 with the rectification bridge DB. One end of an inductor L1 is connected to the positive electrode of the capacitor C0 via the IPD control circuit 23. The other end of the inductor L1 is connected to the positive electrode of the smoothing capacitor C3 on the output side. The negative electrodes of the capacitors C0 and C3 are connected to the anode of the diode D2. The cathode of the diode D2 is connected to the one end of the inductor L1. When the IPD control circuit 23 is turned on, a current flows from the capacitor C0 to the capacitor C3 via the inductor L1. When the IPD control circuit 23 is turned off, a regenerative current due to the energy stored in the inductor L1 flows through the capacitor C3 and the diode D2. The ON / OFF timing of the IPD control circuit 23 is variable according to the voltage applied to the control terminal of the IPD control circuit 23. A filter circuit comprising a series circuit of a capacitor C1 and a resistor R1 and a parallel circuit of a capacitor C2 is connected to the control terminal of the IPD control circuit 23, and the output current flowing from the capacitor C3 via the output terminal is converted into a voltage by the resistor R2. The signal is fed back via the diode D1. The LED module part 3 of FIG. 1 is connected to the output terminal, and a constant current is supplied .

(Prerequisite configuration 3)
The configuration of the constant current power supply circuit 20 in the configuration 3 which is the premise of the present invention is shown in FIG. A series circuit of an inductor L1 and a switching element Q1 is connected to the output terminal of the rectifier bridge DB in FIG. 1, and a smoothing capacitor C0 is connected to both ends of the switching element Q1 via a diode D1. The switching element Q1 is made of a MOSFET and is ON / OFF controlled by the control circuit 24 at a high frequency. The switching frequency is set higher than the frequency of the commercial AC power supply 1. When the switching element Q1 is turned on, a current flows from the DC output terminal of the rectification bridge DB in FIG. 1 via the inductor L1 and the switching element Q1, and energy is accumulated in the inductor L1. When the switching element Q1 is turned OFF, a current flows from the DC output terminal of the rectifying bridge DB in FIG. 1 to the smoothing capacitor C0 via the inductor L1 and the diode D1, and the stored energy of the inductor L1 is released. The timing when the stored energy of the inductor L1 becomes zero is detected by the secondary winding output of the inductor L1, and the switching element Q1 is turned ON. In addition, the output current is converted into a voltage by the resistor R2 and input to the control terminal of the control circuit 24 via the diode D2, so that the current feedback is configured. The ON period of the switching element Q1 is set so that the output current becomes substantially constant. It is something to control.

  In this circuit configuration, the input current distortion from the commercial AC power supply 1 can be reduced and the input current can be reduced as compared with a case where a capacitor input type DC power supply device in which the smoothing capacitor C0 is directly connected to the output of the rectifier bridge DB is used. Since the current pause period can be eliminated, the input power factor can be improved.

Further, in this example , the configuration of the step-up chopper is used, so that it is possible to cope with a case where a plurality of LED module units 3 in which a large number of LEDs are connected in series are further connected in series .

(Assumption 4)
FIG. 5 shows the configuration of the constant current power supply circuit 20 in the configuration 4 which is a premise of the present invention. One end of an inductor L1 is connected to the positive electrode of the DC output end of the rectifier bridge DB in FIG. 1 via a switching element Q1. The other end of the inductor L1 is connected to the positive electrode of the smoothing capacitor C0 on the output side. The negative electrode of the capacitor C0 is connected to the negative electrode of the DC output terminal of the rectifier bridge DB and the anode of the diode D1. The cathode of the diode D1 is connected to the one end of the inductor L1. The switching element Q1 is composed of a MOSFET, and is turned ON / OFF by the control circuit 24 at a high frequency. The switching frequency is set higher than the frequency of the commercial AC power supply 1. When the switching element Q1 is turned on, the capacitor C0 is charged via the inductor L1 from the DC output terminal of the rectification bridge DB. When the switching element Q1 is turned OFF, a regenerative current due to the energy stored in the inductor L1 flows through the capacitor C0 and the diode D1. Further, the output current is converted into a voltage by the resistor R2 and input to the control terminal of the control circuit 24 via the diode D2, so that a current feedback configuration is established, and the switching element Q1 is turned ON / OFF so that the output current becomes substantially constant. Is to control.

  Even in this circuit configuration, distortion of the input current from the commercial AC power supply 1 can be reduced as compared with the case where a capacitor input type DC power supply device in which the smoothing capacitor C0 is directly connected to the output of the rectifier bridge DB is used. Since the current pause period can be eliminated, the input power factor can be improved.

Further, in this example , since the smoothing capacitor C0 is connected to the output of the rectification bridge DB via the inductor L1, the inductor L1 even if the switching element Q1 is turned on when the voltage of the smoothing capacitor C0 is low when the power is turned on. This also has the effect of reducing the inrush current.

Furthermore, since the configuration of the step-down chopper is used in this example , a large voltage drop loss is involved even in an application in which only one 12V LED module or 24V LED module is driven by a commercial AC power source, for example. It can drive without. In other words, in the non-switching type constant current power supply circuit illustrated in FIG. 10, when only one 12V LED module or 24V LED module is lit and driven by a commercial AC power supply, a large voltage drop loss occurs. However, in this example , since the switching power supply is used, the voltage drop loss can be reduced. For example, it is particularly efficient when applied to a low-power application such as a nightlight in a bedroom or a footlamp. It will be a thing .

(Assumption 5)
The configuration of the constant current power supply circuit 20 in the configuration 5 which is the premise of the present invention is shown in FIG. A series circuit of a switching element Q1 and an inductor L1 is connected to the DC output terminal of the rectifier bridge DB in FIG. 1, and a smoothing capacitor C0 is connected to both ends of the inductor L1 via a diode D1. The switching element Q1 is composed of a MOSFET, and is turned ON / OFF by the control circuit 24 at a high frequency. The switching frequency is set higher than the frequency of the commercial AC power supply 1. When the switching element Q1 is turned on, the inductor L1 is connected to the DC output terminal of the rectifier bridge DB, and electromagnetic energy is accumulated in the inductor L1. When the switching element Q1 is turned off, a counter electromotive voltage due to the energy stored in the inductor L1 is generated, and the capacitor C0 is charged from the inductor L1 through the diode D1. At this time, the capacitor C0 is charged so as to have a polarity opposite to the polarity of the DC output terminal of the rectification bridge DB. Further, the output current is converted into a voltage by the resistor R1, and is fed back to the control terminal of the control circuit 24 via the resistor R2, the Zener diode ZD3, and the photocoupler PC as an insulating means, and the current feedback configuration is made. It controls ON / OFF of the switching element Q1 so as to be substantially constant.

  Even in this circuit configuration, distortion of the input current from the commercial AC power supply 1 can be reduced as compared with the case where a capacitor input type DC power supply device in which the smoothing capacitor C0 is directly connected to the output of the rectifier bridge DB is used. Since the current pause period can be eliminated, the input power factor can be improved.

  In addition, since there is no path through which current flows directly from the output of the rectifying bridge DB to the smoothing capacitor C0, there is an effect of eliminating inrush current when the power is turned on.

In addition, in this example , the configuration of the step-up / step-down chopper is used, so it can be used in a wide range regardless of whether the drive voltage of the LED module is high or low, for example, it can be used for lighting one LED. In addition, there is an effect that can cope with a case where a plurality of LED modules in which a large number of LEDs are connected in series are further connected in series.

In other words, since a constant current flows without being affected by the number of LED elements, for example, it is possible to develop lighting fixtures corresponding to any number of LEDs from 1 to 10 with one power supply circuit capable of handling up to 10 LEDs. I can do it. In the following embodiments, a circuit configuration capable of dimming control by varying the ON / OFF duty ratio of the switch elements connected in series to the LED module portion will be described while further having the characteristics .

Example 1
FIG. 11 shows a basic circuit configuration of dimming control. In this embodiment, in the basic configuration of FIG. 1, a switch element Q is connected in series to a plurality of LED elements of the LED module unit 3, and the effective current flowing through the LED module unit 3 is controlled by turning the switch element Q on and off. Is. The switch element Q is made of, for example, a MOSFET, and the ON / OFF control is performed at a high frequency such that the flickering of the light is inconspicuous. By changing the ON / OFF ratio, the effective current flowing through the LED can be varied, The dimming control of the LED module unit 3 can be performed.

A specific example of the configuration of a timer circuit for turning on / off the switching element Q is shown in FIG. This circuit is an example in which an astable multivibrator is configured using a comparator CP, resistors R1 to R4, RL, and a capacitor C. When the resistor R1 is varied, the ON interval is changed, and when the resistor R2 is varied, the OFF interval is changed. This signal is input as the gate signal V _G of the MOSFET serving as the switch element Q in FIG. 11, and the resistor R1 is provided as a rotary or slide variable resistor (volume) and rotated outside the lighting fixture. By controlling the ON section, it is possible to configure a light output variable type lighting fixture using the LED module section. In this case, since the LED current can be controlled constant as described above, there is no current variation due to the influence of the electrical characteristics of the LED element, and a stable light output and the life of the LED element can be ensured. Further, for example, even when the number of LEDs is set to an arbitrary number (1 to 10) up to 10, dimming can be performed while flowing the same constant current.

  The timer circuit of FIG. 12 is an example in which the ON section and the OFF section are changed, but the same effect can be obtained by duty control means that changes the ON / OFF ratio with a constant period. Further, the resistor R2 of the timer circuit of FIG. 12 can be varied, and the dimming control can be performed by changing the effective current value of the LED element by changing the OFF period while keeping the ON period constant.

The present embodiment is an effective means as a means for dimming control while utilizing the features of the presupposed configurations 1 to 5. Other dimming means, for example, means for changing the voltage amplitude, require very difficult control in the constant current circuit system. Further, if the current itself is changed, the constant current control is not performed, so that it becomes impossible to suppress the variation in the LED current due to the variation in the Vf of the LED element. In addition, it is impossible to make use of the characteristics of a constant current circuit that allows the same current to flow through one to a plurality of LED series circuits with one power source without being affected by the number of LED elements .

(Example 2)
FIG. 13 shows the configuration of the second embodiment. Unlike the embodiment of FIG. 11, the present embodiment differs from the embodiment of FIG. 11 only in that LED elements are connected in series in that the switch element Q for dimming control is configured on the power supply side. By providing the switch element Q on the power supply side, the number of parts of the LED module part can be reduced, and the lamp of the LED module part can be made small, so that a small and thin lighting fixture can be realized. In addition, by providing a dimming control circuit section (see FIG. 12) in the power supply section, the lamp of the LED module section is further reduced, and there is less fixture wiring, which makes it possible to reduce the size and cost of the lighting fixture. is doing.

FIG. 14 shows a specific circuit configuration example of the constant current power supply circuit 20 in the DC power supply device 2 of FIG. The configuration of the constant current power supply circuit 20 is the same as the configuration 1 which is the premise shown in FIG. 2, except that the switch element Q is connected in series with its output terminal. The switch element Q is turned on and off at a high frequency (for example, several hundred Hz to several KHz) so that the flicker of the light is not noticeable, and the effective current flowing in the LED is varied by changing the ratio of the on and off. Thus, the dimming control of the LED module unit 3 can be performed. Then, during the period when the switch element Q is ON, the IPD control circuit 23 controls the ON / OFF of the current flowing through the primary winding of the transformer T1 so that the current detected by the current detection means 22 is substantially constant. To do. The switching frequency by the IPD control circuit 23 is sufficiently higher than the switching frequency of the switch element Q, for example, about several tens to several hundreds KHz. By using such a high frequency, the transformer T1 can be reduced in size .

(Example 3)
FIG. 15 shows the configuration of the third embodiment. In the present embodiment, a plurality of LED module units 3-1 and 3-2 are connected in parallel, and the DC power supply unit uses a common circuit unit (rectifier DB and smoothing capacitor C0) for rectifying and smoothing the AC power supply 1 to provide a constant current power supply circuit. 20-1 and 20-2 are provided separately, and the constant current DC output side is connected to the LED module sections 3-1 and 3-2 via individual switch elements Q-1 and Q-2. It is a feature. In order to configure a constant current power supply circuit, current detection is performed by current detection means, and current flowing through the load is controlled by applying current feedback to the control means of the DC voltage conversion circuit so that the load is connected in parallel. If constant current control is performed on the current flowing through each load, as shown in FIG. 15, two or more DC voltage conversion circuits 21-1 and 22-2 are connected, and current detection means 22- are individually connected. It is necessary to provide constant current control by providing 1 and 2-2. If constant current control is performed with one DC voltage conversion circuit for the LED modules 3-1 and 3-2 in two rows connected in parallel, the total current in the two rows can be made constant. Since the current of the LED module cannot be controlled to be constant, two independent circuits are required. The switch elements Q-1 and Q-2 may be provided in the LED module units 3-1 and 3-2, or may be provided in the constant current power supply circuits 20-1 and 20-2. In this embodiment, a noise prevention circuit for an AC power supply unit, a fuse, a ZNR for lightning surge countermeasures, a rectifier DB, a smoothing capacitor C0, an input harmonic distortion improvement circuit if necessary, an inrush current suppression circuit to the smoothing capacitor, etc. There is an advantage that can be shared .

Example 4
FIG. 16 shows the configuration of the fourth embodiment. In the present embodiment, the signal conversion circuit 25 that receives the dimming signal from the outside and converts it into the ON / OFF control signal of the switch element Q in the second embodiment is provided. As the dimming signal input from the outside, for example, a rectangular wave signal (frequency: 1 kHz, DC voltage amplitude: 10 V) having a constant frequency and variable duty as shown in FIG. 17 is used. This dimming signal is input through the rectifier DB2 for preventing erroneous connection, the input voltage is insulated by the photocoupler PC, the waveform is improved by the two-stage transistors Tr1 and Tr2, and the input rectangular wave signal and The switch element Q is ON / OFF controlled with a signal having the same duty ratio.

  According to the present embodiment, a dimmer provided outside the LED lighting apparatus, for example, a dimming signal is sent from an external wall switch, a control device, etc., so that the dimming control can be performed by remote operation. Yes.

Further, as shown in FIG. 18, as a dimming signal from the outside, for example, a DC voltage that is variable from 1 V to 10 V is input, and the duty circuit can receive ON / OFF ratio variable by the timer circuit IC1. The switch element Q connected to the LED module unit 3 in series may be controlled to be dimmed by ON / OFF control. Further, even when the external dimming signal is a DMX conversion signal having an address or the like, the conversion signal is finally converted into a rectangular wave signal having a variable duty and connected to the LED module unit 3 in series. Q may be controlled by dimming by controlling oN · OFF the.

(Comparative Example 1)
FIG. 19 shows the configuration of Comparative Example 1 for the present invention . In FIG. 19, a constant current function is achieved by a combination of the constant voltage circuit 2a (see FIG. 9) shown in the conventional example of FIG. 8 and the LED module section 3a (see FIG. 10) having a constant current function. The dimming control is performed by ON / OFF control of the base terminals of the transistors Q1 to Q4 by the switch element Q. Unlike the first to fourth embodiments, this example is a circuit unit that can perform dimming control while having a constant current function in an LED lighting device having a constant current function in the LED module unit 3a.

In addition, although the flyback type power supply shown in FIG. 14 was illustrated as a direct current voltage conversion circuit of Examples 1 to 4 of dimming control, a non-insulated step-down chopper circuit configuration using the IPD of FIG. Needless to say, the chopper circuit configuration of FIGS. 4 to 6 is not particularly limited as long as the configuration is a DC-DC converter. Further, during the period when the switch element Q is OFF, the feedback control for constant current is substantially suspended, and during the period when the switch element Q is ON, the feedback control for constant current is resumed. You may comprise as follows .

  INDUSTRIAL APPLICABILITY The present invention can be used for lighting devices and lighting fixtures using LEDs, for example, stand lighting using a plurality of LEDs arranged side by side, nightlights, foot lamps, road signal lights, train crossing warning signal lights, spot lights, and the like.

It is a circuit diagram which shows the basic composition used as the premise of this invention. It is a principal part circuit diagram of the structure 1 used as the premise of this invention. It is a principal part circuit diagram of the structure 2 used as the premise of this invention. It is a principal part circuit diagram of the structure 3 used as the premise of this invention. It is a principal part circuit diagram of the structure 4 used as the premise of this invention. It is a principal part circuit diagram of the structure 5 used as the premise of this invention. It is a schematic block diagram of the conventional LED lighting device. It is a schematic block diagram of the other conventional LED lighting device. It is a circuit diagram which shows the conventional constant voltage output type power supply circuit. It is a circuit diagram which shows the conventional non-switching type constant current power supply circuit. It is a circuit diagram of Example 1 of the present invention. It is a circuit diagram of the timer circuit used for Example 1 of the present invention. It is a circuit diagram of Example 2 of the present invention. It is a principal part circuit diagram of Example 2 of this invention. It is a circuit diagram of Example 3 of the present invention. It is a circuit diagram of Example 4 of the present invention. It is a wave form diagram which illustrates the light control signal used for Example 4 of the present invention. It is a principal part circuit diagram of the modification of Example 4 of this invention. It is a circuit diagram of the comparative example 1 with respect to this invention.

DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 DC power supply device 20 Constant current power supply circuit 21 DC voltage conversion circuit 22 Current detection means 3 LED module part Q Switch element

Claims (6)

An LED lighting device comprising: a DC power supply device that receives an AC power supply and outputs a DC voltage; and an LED module unit that is mounted with an LED element that is lit by receiving the DC voltage, wherein one LED element is provided. Alternatively, the DC power supply device includes a rectifying means for rectifying the AC power supply, a switching element connected in series to the output of the rectifying means, and a primary winding at the output of the rectifying means via the switching element. A transformer connected to the secondary winding of the transformer, a current detection means for detecting a current output from the rectification smoothing means to the LED module unit, and a detection output of the current detection means This is a one-stone forward switching power supply circuit consisting of a control circuit that controls the ON / OFF of the switching element so that the output current is substantially constant. A switching element is provided in series at the output end of the DC power supply device or the LED module section, and intermittent driving means for turning the switching element ON / OFF at a high frequency so as not to feel flickering, and the ON / OFF ratio of the switching element An LED lighting device comprising a dimming means for changing output light by changing an effective current flowing through the LED element by changing the current . An LED lighting device comprising: a DC power supply device that receives an AC power supply and outputs a DC voltage; and an LED module unit that is mounted with an LED element that is lit by receiving the DC voltage, wherein one LED element is provided. Alternatively, the DC power supply device includes a rectifier that rectifies an AC power supply, a chopper circuit that includes a switching element connected to the output of the rectifier, an inductor, a diode, and a smoothing capacitor, and the smoothing capacitor and the output. Current detection means inserted in series between the terminals, and a control circuit that receives the detection output of the current detection means and controls ON / OFF of the switching element so that the output current becomes substantially constant , the DC A switch element is provided in series at the output end of the power supply device or the LED module part, so that the switch element does not feel flicker. Characterized in that there is provided intermittent drive means for turning ON / OFF at a high frequency and dimming means for changing output light by changing the effective current flowing in the LED element by changing the ON / OFF ratio of the switch element. LED lighting device. According to claim 1 or 2, LED lighting device you further comprising a timer circuit for varying connected to the control terminal of the ratio of the ON · OFF of the switching element of the switching element. 3. The LED lighting device according to claim 1 , further comprising signal conversion means for converting a dimming signal input from the outside into an ON / OFF control signal for the switch element. 5. The LED lighting device according to claim 4, wherein the dimming signal input from the outside is either a duty variable rectangular wave signal, a level variable DC voltage, or a DMX conversion signal. A plurality of LED module units according to claim 1 or 2 are connected in parallel, and the DC power supply unit shares a circuit unit for rectifying and smoothing the AC power source, and the constant current DC output side is connected to each LED module unit via individual switch elements. LED lighting device characterized by being connected.

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