JP2007227155A - Power supply circuit for illumination, lighting system, and illumination system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply circuit for illumination capable of reducing power loss generated for phase adjustment, in a power supply circuit for illumination used by being connected to a phase control type dimmer; to provide a lighting system; and to provide an illumination system. <P>SOLUTION: This power supply circuit is provided with: reception terminals 31 and 32 for receiving an A.C. power voltage Vout having an on-phase angle adjusted by a phase control dimmer 2 for controlling the on-phase angle by turning on/off an A.C. power voltage Vac by using a thyristor Q1; a capacitor 1 connected between the reception terminals 31 and 32; a constant current circuit 34 for carrying a preset constant current in parallel with the capacitor 1; a D.C.-D.C. converter 33 for outputting power in response to a duty ratio of a voltage across the capacitor 1; and output terminals 35 and 36 for supplying power output from the D.C.-D.C. converter 33 to an externally-connected LED 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination power supply circuit that performs dimming by connecting a phase control dimmer, an illumination device, and an illumination system using the same.

  FIG. 13 is a circuit diagram illustrating a configuration of a lighting system according to the background art (see, for example, Patent Document 1 and Patent Document 2). An illumination system 101 shown in FIG. 13 dims a light emitting diode by phase control, and includes a dimmer 102, an illumination power supply circuit 103, and a light emitting diode 104. The dimmer 102 is a phase control type dimmer, and includes a thyristor 106 that is a switching element that is turned off when a flowing current falls below a predetermined holding current, a control unit 107 thereof, a variable resistor 105 that changes the degree of dimming, and the like. Has been.

  A commercial AC power supply voltage Vac is supplied to the dimmer 102, and the control unit 107 controls the ON phase angle of the switching element according to the resistance value of the variable resistor 105, whereby the duty ratio of the AC power supply voltage is set. The light emitting diode 104 connected to the illumination power supply circuit 103 is dimmed by changing the amount of power supplied to the illumination power supply circuit 103.

  In the phase control type dimmer 102 configured as described above, if a switching element such as a thyristor that turns off when the flowing current falls below a predetermined holding current is used, the switching element can be controlled by simply controlling the on-phase angle. Since the duty ratio of the power supply voltage, that is, the power can be adjusted, the dimmer can be simplified. For this reason, a switching element such as a thyristor that turns off when the flowing current falls below a predetermined holding current is widely used as the dimming switching element.

  The illumination power supply circuit 103 corresponds to the diode bridge 110 that rectifies the AC power supply voltage output from the dimmer 102, the capacitor 111 that smoothes the voltage rectified by the diode bridge 110, and the voltage smoothed by the capacitor 111. And a DC-DC converter 112 that outputs a direct current for light emission of the light emitting diode 104.

  The DC-DC converter 112 is a one-stone flyback converter including, for example, a step-down transformer 113, a power MOSFET 114, a power MOSFET built-in diode 115, an output rectifier diode 116, an output smoothing capacitor 117, and the like. In order to prevent the switching noise of the DC-DC converter 112 from leaking to the outside, a noise prevention capacitor 109 is connected between the input terminals of the diode bridge 110. Further, a resistor 108 is connected in parallel with the capacitor 109. As shown in FIG. 14, an illumination power supply circuit 103a in which the power factor is improved by omitting the capacitor 111 is also known.

  In the illumination power supply circuits 103 and 103a configured as described above, the capacitor 109 is for noise prevention and often forms a filter in combination with an unillustrated inductor element, and is distributed to the upstream and downstream stages of the inductor element. May be provided. When the AC power supply voltage is supplied from the dimmer 102 to the illumination power supply circuits 103 and 103a, the phase of the input current is advanced by the capacitor 109. Therefore, a phase adjustment resistor 108 is provided to reduce the phase advance of the input current.

FIG. 15 is a waveform diagram showing the phase relationship between the input power supply voltage Vin and the input current in the illumination power supply circuit 103 shown in FIG. With respect to the input power supply voltage Vin shown in (A0), the charging current _IC111 in the smoothing capacitor 111 is pulsed as shown in (C0). The current I _C109 flowing through the capacitor 109 and the current I _R108 flowing through the resistor 108 over the entire phase angle flow as (D0) and (E0), respectively. As a result, the combined input current Iin is represented by (F0). Thus, at the phase angle where the pulsed current shown in (C0) does not exist, the influence of the phase advance current by the noise preventing capacitor 109 becomes significant.

  FIG. 16 is a waveform diagram showing the relationship between the input power supply voltage Vin and the input current Iin in the illumination power supply circuit 103a shown in FIG. (A1) shows the input power supply voltage Vin and the input current Iin when the phase advance current by the capacitor 109 is negligibly small with respect to the input current Iin. In this case, the input power supply voltage Vin and the input current Iin have substantially the same phase. On the other hand, when the illumination power supply circuit 103a is in a no load state or a light load state in which the DC-DC converter 112 is stopped, for example, the phase of the current by the capacitor 109 increases.

  (B1), (C1), and (D1) in FIG. 16 are waveform diagrams showing the phase of the input current Iin due to the difference in resistance value of the resistor. (B1) shows an input current phase when the resistance value of the resistor 108 is considerably large, and is a phase advance current (phase angle α1) close to 90 degrees with respect to the input power supply voltage Vin. (C1) and (D1) indicate the input current phase when the resistance value of the resistor 108 is sequentially reduced.

  FIG. 17 shows that the on-phase angle of the thyristor 106 is (180 degrees−α1) in the dimmer 102 in the state where the input current Iin in FIG. 16 (B1), that is, the leading phase of the phase angle α1 close to 90 degrees. It is a signal waveform diagram for demonstrating operation | movement of the light control device 102 when set large exceeding it. (A2) shows a control signal for turning on the thyristor 106, (B2) shows an on / off state of the thyristor 106, and (C2) shows an input power supply voltage Vin in the illumination power supply circuit 103a. (D2) shows the input current Iin when the thyristor 106 is always on for simplicity of explanation.

  As shown in FIG. 17, when the thyristor 106 is turned on at a timing T1 exceeding (180 degrees -α1), the input current Iin is at the zero cross point (timing T2) of the input power supply voltage Vin that should be turned off. Does not become zero, the thyristor 106 is not turned off and remains turned on until the timing T3 when the phase angle is delayed by (180 degrees−α1). For this reason, the voltage indicated by the wavy line in (C2) is input to the illumination power supply circuit 103a as the input power supply voltage Vin. As a result, the light emission of the light emitting diode 104 cannot be properly adjusted, or the light emission flickers. Problem arises.

  Similarly, when the thyristor 106 is turned on at a phase angle earlier than (180 degrees−α1), the thyristor 106 that should be turned off at a phase angle of 180 degrees is (180 degrees−α1). Since the light is turned off at the phase angle, the light emission of the light emitting diode 104 cannot be adjusted correctly or the light emission flickers.

  Here, as shown in FIGS. 16C1 and 16D1, when the resistance value of the resistor 108 is sequentially decreased, the advance phase angle of the phase advance current is sequentially decreased as α2 and α3.

  Therefore, conventionally, an allowable maximum phase advance angle α0, which is the maximum that allows the advance of the phase advance current, is preset in the specifications, and the phase angle α of the dimming range by the dimmer 102 is 0 degree ≦ α <. The range is limited to the range of (180 degrees−α0), that is, the range of the phase angle (180 degrees−α0) ≦ α <180 degrees is set as the on-prohibited phase angle that prohibits the thyristor 106 from being turned on. . For example, if the phase angle α3 is set as the allowable maximum advance angle α0, the phase angle α in the dimming range by the dimmer 102 is 0 ° ≦ α <(180 ° −α3) as shown in (E1). The range is limited to a range, that is, a range of phase angle (180 degrees−α3) ≦ α <180 degrees is set as an on-prohibited phase angle that prohibits the thyristor 106 from being turned on.

  The on-prohibited phase angle is set similarly in the range of 180 degrees to 360 degrees, but for the sake of easy description, the description of the range of 180 degrees to 360 degrees is omitted below.

Then, the lighting power source circuit 103a, for example, in current load is heavy state of most lighting power supply circuit 103a, the resistance value R ₁₀₈ of the resistor 108 so that the phase angle advances the leading phase current is less than the allowable maximum advance phase angle α0 Is set to reduce the influence of the phase advance current by the capacitor 109, so that the thyristor 106 is not turned on at the phase timing at which the above problem occurs.
JP 2004-335128 A JP 2004-327152 A

Incidentally, in the illumination power supply circuits 103 and 103a configured as described above, the resistance value R ₁₀₈ of the phase adjusting resistor ₁₀₈ and the power consumption P thereof are given by the following equations (1) and (2). .
tan α = 2πf × C ₁₀₉ R ₁₀₈
R ₁₀₈ = tan α / 2πfC (1)
P = Vin ² / R ₁₀₈ (2)
Now, the capacitance of the noise preventing capacitor C109 is C ₁₀₉ = 0.1 μF, and the phase control signal range of the dimmer 102 is up to 170 degrees, that is, the on-prohibited phase angle is set to the phase angle 170 degrees ≦ α <180 degrees. Since the allowable advance angle, that is, the allowable maximum advance angle α0 is 10 degrees, from the formula (1),
R ₁₀₈ = tan 10 ° / (2πf × 0.1 × 10 ⁶ ) ≈4.7 kΩ
The power consumption P is calculated from the equation (2).
P = 100 ² /4.7 kΩ≈2.1 W
(However, input power supply voltage Vin is 100V, 60Hz)
From the above, although it is greatly affected by the characteristics of the dimmer and the capacitance value of the anti-noise capacitor, it is the resistance for phase adjustment that is necessary to support the phase control type dimmer as the illumination power supply circuit. For example, in the LED (Light Emitting Diode) illumination, the loss is inconveniently large so that it cannot be ignored from the current situation where 10W to 20W is mainstream. In particular, in order to use an LED lighting device using such a power supply circuit for illumination as an alternative to a discharge lamp with good luminous efficiency, it is necessary to improve luminous efficiency and reduce loss in phase adjusting resistors. There is a need to do it.

  The present invention has been made in view of such a problem, and can reduce power loss caused by phase adjustment in an illumination power supply circuit used by being connected to a phase-control dimmer. An object of the present invention is to provide a lighting power circuit that can be used. It is another object of the present invention to provide an illumination device and an illumination system using such an illumination power supply circuit.

  In order to achieve the above-described object, the illumination power supply circuit according to the first means of the present invention turns on and off the AC power supply voltage using a switching element that turns off when the flowing current falls below a predetermined holding current. The first and second power receiving terminals for receiving the AC power supply voltage whose on-phase angle is adjusted by the phase control dimmer that controls the on-phase angle with the first and second power receiving terminals. Output from the power control unit, a constant current circuit that supplies a preset constant current in parallel with the capacitor, a power control unit that outputs power according to a duty ratio at a voltage across the capacitor, and The first and second output terminals for supplying the power to the light emitting unit connected to the outside.

  In the illumination power supply circuit described above, the phase control dimmer sets the on phase angle to a phase angle excluding a range of a preset on-prohibited phase angle, and the constant current circuit includes: The current value of the constant current is set so that the zero cross phase angle at which the current flowing between the first and second power receiving terminals becomes zero is set within the range of the on-prohibited phase angle.

  The illumination power supply circuit may further include a duty ratio detection unit that detects a duty ratio of the voltage between the first and second power receiving terminals, and the power control unit is detected by the duty ratio detection unit. The power is increased or decreased according to the increase or decrease of the duty ratio.

  In the illumination power supply circuit described above, the duty ratio detection unit detects the duty ratio based on a current flowing through the constant current circuit.

  In the illumination power supply circuit described above, the constant current circuit is further characterized in that the constant current is equal to or higher than the holding current.

  In the illumination power supply circuit described above, the power control unit turns on the illumination load with a first rectification bridge that rectifies the voltage across the capacitor and a rectified voltage rectified by the first rectification bridge. And a power conversion unit for converting the power into the power.

  In the illumination power supply circuit described above, the constant current circuit is connected in parallel with the capacitor via a second rectification bridge that rectifies the voltage across the capacitor.

  In the above illumination power supply circuit, the constant current circuit includes a cathode of a first diode having an anode connected to one end of the capacitor and a cathode of a second diode having an anode connected to the other end of the capacitor. It is connected between the connection point and the output terminal that outputs the rectified voltage in the first rectifier bridge.

  In the illumination power supply circuit described above, the power control unit is connected between output terminals for outputting the rectified voltage in the first rectification bridge via a backflow prevention diode for preventing a backflow of current. The capacitor is further provided, and the constant current circuit is connected in parallel with the capacitor via the first rectification bridge.

  In the illumination power supply circuit described above, the constant current circuit is configured by an emitter-follower circuit of a transistor that supplies a current according to a preset voltage.

  In the illumination power supply circuit described above, the constant current circuit is configured by a current mirror circuit of a transistor that supplies a current according to a preset voltage.

  In the illumination power supply circuit described above, the set voltage is obtained by smoothing the rectified voltage in the first rectifier bridge with a capacitor and dividing the resistance.

  In the illumination power supply circuit described above, the power control unit further includes a smoothing capacitor that smoothes the rectified voltage rectified by the first rectification bridge, and the power conversion unit is smoothed by the smoothing capacitor. It is characterized in that it is constituted by a DC-DC converter that generates DC power from the obtained voltage and outputs it as the power.

  In the illumination power supply circuit described above, the power control unit includes a first rectifier bridge that rectifies the voltage across the capacitor, a smoothing capacitor that smoothes the rectified voltage rectified by the first rectifier bridge, and A DC-DC converter that generates DC power from the voltage smoothed by the smoothing capacitor and outputs the DC power as the power, the DC-DC converter stepping down the voltage smoothed by the smoothing capacitor A transformer is provided, and the set voltage is obtained from a winding wound around the transformer.

  And the illuminating device which concerns on the 2nd means of this invention is equipped with the light emission part and the illumination power supply circuit for making the said light emission part light-emit, The said illumination power supply circuit is the illumination in any one of the above-mentioned Power supply circuit.

  Moreover, in the above-described lighting device, the light emitting unit is a light emitting diode.

  Furthermore, an illumination system according to a third means of the present invention includes a light emitting unit, a phase control dimmer that outputs an AC power supply voltage with a duty ratio set to dimm the brightness of the light emitting unit, An illumination power supply circuit that causes the light emitting unit to emit light based on an AC power supply voltage output from the phase control dimmer, and the phase control dimmer receives a dimming instruction that indicates the brightness of the light emitting unit A receiving unit, a switching element that turns on and off the AC power supply voltage and turns off when a flowing current falls below a predetermined holding current; and an on that turns on the switching element in response to a dimming instruction received by the receiving unit A control unit that controls a phase angle, wherein the illumination power supply circuit is the illumination power supply circuit according to any one of the above, and the switching element is provided by the first and second power receiving terminals. More on, and characterized in that receiving the AC power supply voltage is turned off.

  In the illumination power supply circuit having such a configuration, and the illumination device and illumination system using the same, the phase control dimmer uses the switching element that turns off when the flowing current falls below a predetermined holding current to generate the AC power supply voltage. The AC power supply voltage whose on phase angle is adjusted by turning on and off is received by the power receiving terminals of the first and second power receiving terminals. Moreover, noise leaking to the outside is reduced by the capacitor connected between the first and second power receiving terminals. Then, a constant current for phase adjustment set in advance in parallel with the capacitor is caused to flow by the constant current circuit, so that the advance of the current phase by the capacitor is reduced. And the electric power according to the duty ratio in the both-ends voltage of the said capacitor | condenser is supplied to the light emission part connected to the 1st and 2nd output terminal by the electric power control part. In this case, power loss caused by phase adjustment can be reduced as compared with the case where phase adjustment is performed by passing a current through a resistor connected in parallel with the capacitor.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a circuit diagram showing an example of the configuration of the illumination system according to the first embodiment of the present invention. An illumination system 1 shown in FIG. 1 includes a phase control dimmer 2 and an illumination device 5 including an illumination power supply circuit 3 and an LED 4 (light emitting unit). The phase control dimmer 2 is a phase control type dimmer that turns on and off the AC power supply voltage Vac using the thyristor Q1 and the thyristor Q1, which are switching elements that are turned off when the flowing current falls below a predetermined holding current. The controller 21 that controls the ON phase angle, the variable resistor VR (accepting unit) that is a volume switch that changes the degree of dimming, and the AC power supply voltage Vout whose ON phase angle is controlled by the thyristor Q1 are supplied to the illumination power supply circuit 3. It consists of connection terminals 22 and 23 for output.

  The commercial AC power supply voltage Vac is supplied to the phase control dimmer 2, and the thyristor is controlled according to the resistance value of the variable resistor VR, that is, the dimming instruction, by the control unit 21 configured using, for example, a microcomputer. By controlling the on-phase angle of Q1, the duty ratio of the AC power supply voltage is changed, and the amount of power supplied to the illumination power supply circuit 3 is changed, thereby dimming the LED 4 connected to the illumination power supply circuit 3. Is supposed to do.

  The range of the on-prohibited phase angle is set in advance in the control unit 21, and the control unit 21 sets the on-phase angle of the thyristor Q1 within the range of the phase angle excluding the range of the on-prohibited phase angle. The on-prohibited phase angle α is set, for example, in a range of phase angle 170 degrees ≦ α <180 degrees. Note that the range of the on-prohibited phase angle α may be set at the beginning and end of the entire phase range, for example, 0 degrees ≦ α <10 degrees and 170 degrees ≦ α <180 degrees.

  Instead of the thyristor Q1, another switching element that turns off when the flowing current falls below a predetermined holding current, such as an SCR (Silicon Controlled Rectifier) or a triac, may be used.

  The illumination power supply circuit 3 is connected between the power receiving terminals 31 and 32 (first and second power receiving terminals) for receiving the AC power supply voltage Vout output from the phase control dimmer 2 and the power receiving terminals 31 and 32. The noise-preventing capacitor C1, the diode bridge DB1 (first rectification bridge) that rectifies the voltage across the capacitor C1 and outputs the rectified voltage Vdb1, the smoothing capacitor C2 that smoothes the rectified voltage Vdb1, and the smoothing capacitor A DC-DC converter 33 (power converter) that generates DC power from the rectified voltage Vdb1 smoothed by the capacitor C2 and converts it into a current for lighting the LED 4, and a DC current output from the DC-DC converter 33 Output terminals 35 and 36 (first and second output terminals) for supplying to the LED 4 and a diode for rectifying the voltage across the capacitor C1. Doburijji and DB2 (second rectifier bridge) is configured by a constant current circuit 34 connected in parallel with the capacitor C1 via the diode bridge DB2.

  And LED4 is attached to the output terminals 35 and 36 as a light emission part, and the illuminating device 5 is comprised. The light emitting unit is not limited to the LED, and may be a halogen lamp or a discharge lamp, for example. Moreover, the DC-DC converter 33 should just output the electric power for light emission of a light emission part according to the rectification voltage Vdb1, and may make a light emission part light-emit by voltage output.

Constant current circuit 34, a zero-crossing phase angle input current Iin flowing between the power receiving terminal 31 becomes zero, the current value so as to the range of the on-inhibit phase angle is set to a constant current I ₀ . FIG. 2 is a circuit diagram illustrating an example of the constant current circuit 34. (A) is a constant current diode supplies a constant current D11 (eg, Ishizuka Co., CRD (Current a regulative Diode), intended for use as a constant current circuit 34, a constant current of the current value of the current _{I 0} By using the diode as the constant current circuit 34, the current I ₀ of the constant current circuit 34 can be set in advance.

FIG. 2B is an example of a constant current circuit using an emitter follower circuit. The collector of the transistor Tr11 is connected to one end of the output terminal of the diode bridge DB2, and the emitter of the transistor Tr11 is connected to the diode bridge via the resistor R12. Connected to the other end of the output terminal of DB2, a capacitor C11 is connected in parallel with the resistor R12. Then, the set voltage V _dc is applied to the base of the transistor Tr11 via the resistor R11 by the DC constant voltage source Vdc that outputs a preset DC set voltage V _dc , so that it corresponds to the set voltage V _dc . As a result of the base current flowing, a current I ₀ corresponding to the set voltage V _dc flows.

FIG. 2C is an example of a constant current circuit using a current mirror circuit. The collector of the transistor Tr21 is connected to one end of the output terminal of the diode bridge DB2, and the emitter of the transistor Tr21 is connected to the output terminal of the diode bridge DB2. Connected to the other end. The base of the transistor Tr22 is connected to the base of the transistor Tr21 and the collector of the transistor Tr22, and the emitter of the transistor Tr22 is connected to the other end of the output terminal of the diode bridge DB2. Then, the set voltage V _dc is applied to the collector and base of the transistor Tr22 via the resistor R21 by the DC constant voltage source Vdc that outputs a preset DC set voltage V _dc , so that the set voltage V _dc is obtained. As a result of the corresponding current I ₀ flowing through the transistor Tr22, the current I ₀ corresponding to the set voltage V _dc flows through the transistor Tr22 and the transistor Tr21 having a mirror configuration.

  The phase control dimmer 2 is attached to a wall surface of a house, for example, and the lighting device 5 is attached to a ceiling of the house, for example. Then, the connection terminals 22 and 23 in the phase control dimmer 2 and the power reception terminals 31 and 32 in the illumination power supply circuit 3 are connected by the cable CBL1 to configure the illumination system 1.

  Next, operation | movement of the illumination system 1 comprised as mentioned above is demonstrated. First, when the user operates the volume switch of the phase control dimmer 2 to dim the LED 4 and sets the resistance value of the variable resistor VR, the control unit 21 controls the thyristor Q1 according to the resistance value of the variable resistor VR. The on phase angle is controlled. Then, the AC power supply voltage Vout whose on phase angle is controlled by the thyristor Q1 is output to the power receiving terminals 31 and 32 via the connection terminals 22 and 23 and the cable CBL1, and the AC power supply voltage Vout is received by the power receiving terminals 31 and 32. Is received as the input power supply voltage Vin.

Then, the input current Iin, while the advanced phase by the capacitor C1, via the diode bridge DB2 current I ₀ by the constant current circuit 34 is a phase lead input current Iin is reduced for flowing the input current Iin of the zero-crossing phase The angle is set within the range of the on-forbidden phase angle α, for example, the range of phase angle 170 ° ≦ α <180 °.

  As a result, the thyristor Q1 does not turn on at a phase angle that exceeds the zero cross phase angle of the input current Iin. Therefore, the thyristor Q1 cannot be turned off at the zero cross phase angle of the input current Iin that should be turned off. It is suppressed that ON is continued until the cycle. When the thyristor Q1 is turned on before the zero cross phase angle of the input current Iin, the zero cross phase angle of the input current Iin is within a range of, for example, phase angle 170 degrees ≦ α <180 degrees, that is, the phase advance is 10 degrees or less. Therefore, the timing deviation when the thyristor Q1 is turned off is 10 degrees or less. In this case, the off-timing shift due to the phase advance does not become a large value, for example, 90 degrees, so that the influence of the current phase advance on the duty ratio of the input power supply voltage Vin is reduced.

  Then, the duty ratio of the input power supply voltage Vin is set according to the ON phase angle by the thyristor Q1, that is, according to the dimming instruction set by the user using the variable resistor VR. The input power supply voltage Vin is rectified by the diode bridge DB1 and smoothed by the smoothing capacitor C2 to be the rectified voltage Vdb1. In this case, the rectified voltage Vdb1 increases or decreases according to the increase or decrease of the duty ratio of the input power supply voltage Vin.

Then, the DC-DC converter 33, the DC load current _{I L} corresponding to the rectified voltage VDB1, i.e. the load current _{I L} corresponding to the dimming instruction is supplied to the LED4 through the output terminal 35. Then, LED 4 emits light at a brightness corresponding to the load current I _L i.e. dimming instruction.

In this case, the leading phase input current Iin is reduced by current I ₀ is caused to flow by the constant current circuit 34, it is possible to the duty ratio corresponding to the dimming instruction input supply voltage Vin, properly regulating the LED4 It is possible to suppress the occurrence of problems such as inability to light or flickering.

Further, in the illumination power supply circuit 3 shown in FIG. 1, the phase advance angle of the input current Iin is set to the allowable maximum phase advance angle α0, and the phase angle of the zero cross point in the input current Iin is set to α (= 180 degrees−α0). For this, the current value of the current I ₀ may be set so that the current I _C1 flowing through the capacitor C1 is canceled by the input power supply voltage Vin. When the capacitance of the capacitor C1 and C _1, the power loss P generated for a current I ₀ and the phase adjustment is given by the following equation (3), Equation (4).
I ₀ = −I _C1 = ωC ₁ × Vin × (square root of 2) × cos α (3)
P = Vin × I ₀ (4)
3, 4, and 5 are graphs showing power loss P caused by phase adjustment in the illumination power supply circuit 3 shown in FIG. 1 and the illumination power supply circuit 103 according to the background art shown in FIG. 13. is there. The horizontal axis indicates the phase angle α, the vertical axis indicates the power loss P, the square mark indicates the power loss P in the illumination power supply circuit 3, and the circle indicates the power loss P in the illumination power supply circuit 103. 3 shows a case where the capacitance C (= C ₁ = C ₁₀₃ ) of the noise prevention capacitor is 0.1 μF, and FIG. 4 shows the capacitance C (= C ₁ = C _{103 of the} noise prevention capacitor). ) Is 0.01 μF, and FIG. 5 shows a case where the capacitance C (= C ₁ = C ₁₀₃ ) of the noise prevention capacitor is 0.047 μF. As shown in FIG. 3, FIG. 4, and FIG. 5, irrespective of the capacitance of the noise prevention capacitor and the phase angle α (= 180 degrees−α0) of the zero cross point in the input current Iin, The power loss P generated for phase adjustment by the power supply circuit 3 can be reduced.

  For example, instead of using the diode bridge DB2 as in the illumination power supply circuit 3a shown in FIG. 6, a diode D1 (first diode) having an anode connected to one end of the capacitor C1 and the other end of the capacitor C1 A diode D2 (second diode) having an anode connected thereto, and a constant current circuit 34 is connected between a connection point between the cathode of the diode D1 and the cathode of the diode D2 and the low-voltage side output terminal of the diode bridge DB1. It is good also as a structure to be. In this case, since the diode bridge DB2 can be replaced with two diodes, the circuit can be simplified.

  Further, for example, instead of using the diode bridge DB2 as in the illumination power supply circuit 3b shown in FIG. 7, a diode D3 for preventing a backflow is provided to prevent a current from flowing back from the smoothing capacitor C2 to the diode bridge DB1, The constant current circuit 34 may be connected in parallel with the capacitor C1 via the diode bridge DB1 by connecting the constant current circuit 34 between the output terminals of the diode bridge DB1. In this case, the diode bridge DB2 can be replaced with one diode, so that the circuit can be simplified.

Further, for example, in the lighting power supply circuits 3, 3 a, 3 b, a voltage dividing resistor that divides the voltage across the smoothing capacitor C _< b> 2 and the voltage divided by the voltage dividing resistor are set to a constant voltage V _dc. A DC constant voltage source Vdc in the constant current circuit 34 shown in FIGS. 2B and 2C may be configured by a Zener diode.

Further, for example, an illumination power supply circuit 3c shown in FIG. 8 may be used. That is, the DC-DC converter 33 is configured as a one-stone flyback converter by, for example, the step-down transformer T, the power MOSFET Q2, the power MOSFET built-in diode D4, the output rectifier diode D5, the output smoothing capacitor C3, and the like. The output terminal of the output winding n3 in the step-down transformer T is connected to the anode of the diode D7, and the cathode of the diode D7 is connected to the low-voltage side output terminal of the diode bridge DB1 via the capacitor C4. Then, the voltage across the capacitor C4 is converted to a constant voltage V _dc by the Zener diode ZD and supplied to the constant current circuit 34, whereby the constant DC voltage in the constant current circuit 34 shown in FIGS. Source Vdc may be configured. In this case, the constant current circuit 34 can be operated as long as the DC-DC converter 33 continues to operate.

  Further, the illumination power supply circuits 3a and 3c shown in FIGS. 6 and 8 may be configured not to include the smoothing capacitor C2. In the illumination power supply circuit 3b shown in FIG. 7, the smoothing capacitor C2 and the diode D3 are provided. It is good also as a structure which is not provided.

FIG. 9 shows the waveform of the AC power supply voltage Vac and the waveform of the current I ₀ flowing through the constant current circuit 34. A constant current can be secured in almost all phases of the AC power supply voltage Vac.

(Second Embodiment)
Next, an illumination system according to the second embodiment of the present invention will be described. FIG. 10 is a block diagram showing an example of the configuration of an illumination system 1d according to the second embodiment of the present invention. The illumination system 1d shown in FIG. 10 is different from the illumination power supply circuit 3a shown in FIG. 6 in the configuration of the illumination power supply circuit 3d. That is, the illumination power supply circuit 3 d shown in FIG. 10 is different in that the duty ratio detection unit 37 is further provided.

  The duty ratio detection unit 37 outputs the signal S1 at a high level if the input power supply voltage Vin is in an on state, and outputs the signal S1 at a low level if the input power supply voltage Vin is in an off state. A signal S 1 corresponding to the duty ratio of Vin is output to the DC-DC converter 33.

The DC-DC converter 33 increases or decreases the load current I _L to the LED 4, that is, the output power, according to the increase or decrease of the duty ratio of the signal S1. For example, the DC-DC converter 33 generates the load current I _L , that is, the output power to the LED 4 according to the voltage obtained by smoothing the signal S1, that is, the voltage according to the duty ratio of the input power supply voltage Vin. Increase or decrease.

  FIG. 11 is a circuit diagram showing an example of a more detailed configuration of the illumination power supply circuit 3d shown in FIG. In the illumination power supply circuit 3d, the voltage drop of the emitter resistor R4 in the constant current circuit 34 composed of an emitter follower circuit composed of a transistor Tr1, resistors R3, R4, R5, a capacitor C5, a DC constant voltage source Vdc, etc., that is, a constant current circuit. 34 detects the current flowing through the transistor Tr2, drives the photocoupler Pc via the limiting resistor R6, outputs the signal S1 to the DC-DC converter 33, and controls the dimming control according to the signal S1 to the DC-DC converter 33. Is supposed to be done.

  In this case, the resistor R6, the transistor Tr2, and the photocoupler Pc correspond to the duty ratio detection unit 37. And since the duty ratio detection part 37 can detect ON / OFF of the input power supply voltage Vin using the constant current circuit 34, it can simplify a circuit.

  In the illumination systems 1, 1a, 1b, and 1c shown in FIGS. 1, 6, 7, and 8, the phase control dimmer 2 includes the illumination power supply circuit 3, by changing the duty ratio of the AC power supply voltage Vout. The electric power supplied to 3a, 3b, 3c is changed, and light emission of the LED 4 is dimmed. Therefore, if the LED 4 is dimmed by dimming and trying to make the brightness close to extinction, the amount of power supplied from the phase control dimmer 2 to the illumination power supply circuits 3, 3a, 3b, 3c is reduced. The power input to the DC-DC converter 33 decreases to near zero. If it does so, it will become difficult to ensure the electric power for the DC-DC converter 33 to operate | move, operation | movement of the DC-DC converter 33 will become unstable, and there exists a possibility that the light control when darkening LED4 may become unstable. was there.

  On the other hand, in the illumination power supply circuit 3 d shown in FIGS. 10 and 11, the light emission of the LED 4 is dimmed by the DC-DC converter 33 in accordance with the duty ratio of the input power supply voltage Vin detected by the duty ratio detection unit 37. Therefore, even when the LED 4 is dimmed by dimming, it is not necessary to reduce the amount of power supplied from the phase control dimmer 2 to the illumination power supply circuits 3, 3a, 3b, 3c.

Therefore, DC-DC converter 33, as shown in FIG. 12, the duty ratio of the signal S1 is output load current _{I L} in the case of 100% as the maximum load current Imax of LED 4, the duty ratio of the signal S1 is 0% greater, at a duty ratio a that can be secured operating power of the DC-DC converter 33, which is the load current I _L zero, i.e. so as to turn off the LED 4. As a result, even when the LED 4 is dimmed by dimming to obtain a brightness close to extinction, the power for operation of the DC-DC converter 33 is ensured, and therefore the dimming when the LED 4 is dimmed is not good. It can suppress becoming stable.

In the illumination power supply circuit 3d shown in FIGS. 10 and 11, the duty ratio of the AC power supply voltage Vout output from the phase control dimmer 2 is used as a control signal for controlling the output current of the DC-DC converter 33. It is done. When the LED4 is darker dimming reduces the load current _{I L} which is output from the DC-DC converter 33, the input current Iin is also reduced. By the way, the thyristor Q1 is turned off when the flowing current, that is, the input current Iin falls below a predetermined holding current, regardless of the ON control signal from the control unit 21, and the AC power supply voltage Vout is not output from the phase control dimmer 2. . Then, the illumination power supply circuit 3d cannot receive the AC power supply voltage Vout as a dimming control signal, and cannot perform dimming according to the resistance value of the variable resistor VR, that is, the user's dimming instruction. There is a fear.

Therefore, the current I ₀ of the constant current circuit 34 is set to be equal to or larger than the minimum holding current at which the thyristor Q1 can be kept on at a phase angle excluding the range of the on-prohibited phase angle.

  Further, in the lighting power supply circuit 3d shown in FIGS. 10 and 11, since the AC power supply voltage Vout is used as a dimming control signal, the dimming control is performed from the phase control dimmer 2 to the lighting power supply circuit. Compared to the case where the signal is output for dimming, it is not necessary to provide a separate line for transmitting the dimming control signal in addition to the cable CBL1, so that the wiring can be saved.

It is a circuit diagram which shows an example of a structure of the illumination system which concerns on the 1st Embodiment of this invention. It is a circuit diagram which shows an example of the constant current circuit shown in FIG. (A) is an example using a constant current diode, (B) is an example using an emitter follower circuit, and (C) is an example using a current mirror circuit. It is the graph which showed the power loss P which arises for the phase adjustment in the power supply circuit for illumination shown in FIG. 1, and the power supply circuit for illumination which concerns on background art. It is the graph which showed the power loss P which arises for the phase adjustment in the power supply circuit for illumination shown in FIG. 1, and the power supply circuit for illumination which concerns on background art. It is the graph which showed the power loss P which arises for the phase adjustment in the power supply circuit for illumination shown in FIG. 1, and the power supply circuit for illumination which concerns on background art. It is a circuit diagram which shows the modification of the illumination system shown in FIG. It is a circuit diagram which shows the modification of the illumination system shown in FIG. It is a circuit diagram which shows the modification of the illumination system shown in FIG. It is a wave form diagram which shows the waveform of the electric current which flows through a constant current circuit. It is a block diagram which shows an example of a structure of the illumination system which concerns on the 2nd Embodiment of this invention. It is a circuit diagram which shows an example of a more detailed structure of the power supply circuit for illumination shown in FIG. It is explanatory drawing which shows an example of the control characteristic of the DC-DC converter shown in FIG. It is a circuit diagram which shows the structure of the illumination system which concerns on background art. It is a circuit diagram which shows the structure of the illumination system which concerns on background art. It is a wave form diagram which shows the phase relationship of the input power supply voltage and input current in the power supply circuit for illumination shown in FIG. It is a wave form diagram which shows the relationship between the input power supply voltage and input current in the power supply circuit for illumination shown in FIG. It is a signal waveform diagram for demonstrating operation | movement of the dimmer which concerns on background art.

Explanation of symbols

1, 1a, 1b, 1c, 1d Illumination system 2 Phase control dimmer 3, 3a, 3b, 3c, 3d Power supply circuit for illumination 4 LED
DESCRIPTION OF SYMBOLS 5 Illuminating device 21 Control part 22,23 Connection terminal 31,32 Power receiving terminal 33 DC-DC converter 34 Constant current circuit 35,36 Output terminal 37 Duty ratio detection part C1 Capacitor C2 Smoothing capacitor C3 Output smoothing capacitor CBL1 Cable D1, D2 D3 Diode D4 Power MOSFET built-in diode D5 Output rectifier diode D7 Diode DB1, DB2 Diode bridge I _L load current Iin Input current Q1 Thyristor T Step-down transformer VR Variable resistor Vdb1 Rectified voltage V _dc Setting voltage Vdc DC constant voltage source Vin Input power supply voltage Vout AC power supply voltage n3 Output winding

Claims (17)

AC power supply voltage whose on phase angle is adjusted by a phase control dimmer that controls the on phase angle by turning on and off the alternating current power supply voltage using a switching element that turns off when the flowing current falls below a predetermined holding current First and second power receiving terminals for receiving power,
A capacitor connected between the first and second power receiving terminals;
A constant current circuit for supplying a preset constant current in parallel with the capacitor;
A power control unit that outputs power according to a duty ratio in the voltage across the capacitor;
A lighting power supply circuit comprising: first and second output terminals for supplying power output from the power control unit to a light emitting unit connected to the outside. The phase control dimmer sets the on phase angle to a phase angle excluding a preset range of on-prohibited phase angle,
The constant current circuit sets a current value of the constant current so that a zero cross phase angle at which a current flowing between the first and second power receiving terminals becomes zero falls within the range of the on-prohibited phase angle. The illumination power supply circuit according to claim 1. A duty ratio detector for detecting a duty ratio of a voltage between the first and second power receiving terminals;
The illumination power supply circuit according to claim 2, wherein the power control unit increases or decreases the power according to an increase or decrease in the duty ratio detected by the duty ratio detection unit. The illumination power supply circuit according to claim 3, wherein the duty ratio detection unit detects the duty ratio based on a current flowing through the constant current circuit. The lighting power supply circuit according to claim 4, wherein the constant current circuit further sets the constant current to be equal to or greater than the holding current. The power control unit
A first rectifier bridge for rectifying the voltage across the capacitor;
The illumination converter according to claim 1, further comprising: a power conversion unit that converts the rectified voltage rectified by the first rectification bridge into the electric power for lighting the illumination load. Power supply circuit. The illumination power supply circuit according to claim 1, wherein the constant current circuit is connected in parallel with the capacitor via a second rectification bridge that rectifies the voltage across the capacitor. . The constant current circuit includes a connection point between a cathode of a first diode having an anode connected to one end of the capacitor and a cathode of a second diode having an anode connected to the other end of the capacitor; The illumination power supply circuit according to claim 6, wherein the illumination power supply circuit is connected between an output terminal that outputs the rectified voltage. The power control unit
A smoothing capacitor connected between output terminals for outputting the rectified voltage in the first rectification bridge via a backflow prevention diode for preventing a backflow of current;
The illumination power supply circuit according to claim 6, wherein the constant current circuit is connected in parallel to the capacitor via the first rectification bridge. The illumination power supply circuit according to any one of claims 1 to 9, wherein the constant current circuit is configured by an emitter follower circuit of a transistor that supplies a current corresponding to a preset set voltage. The illumination power supply circuit according to any one of claims 1 to 9, wherein the constant current circuit is configured by a current mirror circuit of a transistor that supplies a current corresponding to a preset set voltage. The illumination power supply circuit according to claim 10 or 11, wherein the set voltage is obtained by smoothing the rectified voltage in the first rectifier bridge with a capacitor and dividing the resistance. The power control unit further includes a smoothing capacitor that smoothes the rectified voltage rectified by the first rectification bridge,
The illumination power supply circuit according to claim 6, wherein the power conversion unit includes a DC-DC converter that generates DC power from the voltage smoothed by the smoothing capacitor and outputs the DC power as the power. . The power control unit
A first rectifier bridge for rectifying the voltage across the capacitor;
A smoothing capacitor for smoothing the rectified voltage rectified by the first rectifier bridge;
A DC-DC converter that generates DC power from the voltage smoothed by the smoothing capacitor and outputs the generated DC power; and
The DC-DC converter includes a transformer for stepping down the voltage smoothed by the smoothing capacitor,
The illumination power supply circuit according to claim 10 or 11, wherein the set voltage is obtained from a winding wound around the transformer. A light emitting unit;
A lighting power supply circuit for causing the light emitting section to emit light,
The illumination power supply circuit according to any one of claims 1 to 14, wherein the illumination power supply circuit is the illumination power supply circuit. The lighting device according to claim 15, wherein the light emitting unit is a light emitting diode. A light emitting unit;
A phase control dimmer that outputs an AC power supply voltage with a duty ratio set to dimm the brightness of the light emitting unit;
An illumination power supply circuit that emits light from the light-emitting unit based on the AC power supply voltage output from the phase control dimmer;
The phase control dimmer is
A receiving unit that receives a dimming instruction that indicates the brightness of the light emitting unit;
A switching element that turns on and off the AC power supply voltage and turns off when the flowing current falls below a predetermined holding current;
A control unit that controls an on-phase angle for turning on the switching element in response to a dimming instruction received by the reception unit;
The power supply circuit for illumination is the power supply circuit for illumination according to any one of claims 1 to 14, and receives the AC power supply voltage turned on and off by the switching element by the first and second power receiving terminals. A lighting system characterized by this.

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