Lighting system, and lighting fixture

Abstract

To provide a lighting system capable of reducing the size of the circuit for detecting the input AC voltage, and a lighting fixture.SOLUTION: In a lighting system A1, a rectification circuit 1 rectifies an AC voltage Vi from an AC power supply 8 and outputs the rectified voltage V1. A power supply circuit 2 includes: an inductor L2 on which an inductor current IL2 due to the rectified voltage V1 flows; and a switching element Q1 that turns on and off the inductor current IL2, which generates medium power by converting the rectified voltage V1 into DC intermediate voltage V2. A power conversion circuit 3 performs power conversion operation to convert medium power into output power. The auxiliary winding N1 is magnetically coupled to the inductor L2. A power control unit 4 controls the power conversion operation based on the detection voltage Vd generated in the auxiliary winding N1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a lighting system and a lighting fixture. [Background technology]

[0002] The power supply device of Patent Document 1 is connected to an AC power supply and includes a rectifier, a PFC controller, a DC / DC converter, an input voltage detection circuit, etc. The AC power supply is, for example, a 200V system, and the input AC voltage of the AC power supply is full-wave rectified in the rectifier to become an input voltage (DC voltage). The input voltage is power factor corrected and controlled in the PFC controller to become an output voltage. The output voltage is stepped down and constant current controlled in the DC / DC converter, and output to a load such as an LED lighting device.

[0003] The input voltage detection circuit has two detection resistors connected in series, and detects the DC input voltage that has been full-wave rectified by the rectifier. The input voltage detection circuit inputs an ON signal to the DC / DC converter while the input voltage is applied to the detection resistor. In the power supply device, the input voltage detection circuit detects the input voltage, and does not operate the PFC control unit while the input voltage is not being applied. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-4576 A Summary of the Invention [Problem to be solved by the invention]

[0005] The power supply device of the above-mentioned Patent Document 1 generates a DC input voltage by full-wave rectifying the input AC voltage of the AC power supply, and detects the DC input voltage with an input voltage detection circuit. The operation of the PFC control unit is controlled based on the detection result of the input voltage detection circuit.

[0006] However, the input AC voltage of the AC power supply is, for example, 200 V, and the DC input voltage obtained by full-wave rectifying the input AC voltage is relatively high. Therefore, the input voltage detection circuit is required to have high voltage resistance, which leads to a problem that the circuit size becomes large.

[0007] An object of the present disclosure is to provide a lighting system and a lighting fixture that can reduce the circuit scale for detecting an input AC voltage. [Means for solving the problem]

[0008] A lighting system according to an aspect of the present disclosure converts AC power supplied from an AC power source into DC output power and supplies the output power to a lighting load. The lighting system includes a rectifier circuit, a power supply circuit, a power conversion circuit, an auxiliary winding, and a power control unit. The rectifier circuit rectifies the AC voltage of the AC power source and outputs a rectified voltage. The power supply circuit has an inductor through which an inductor current due to the rectified voltage flows, and a switching element that conducts and cuts off the inductor current, and generates intermediate power by converting the rectified voltage into a DC intermediate voltage. The power conversion circuit performs a power conversion operation to convert the intermediate power to the output power. The auxiliary winding is magnetically coupled to the inductor. The power control unit controls the power conversion operation based on a detection voltage that is a voltage generated in the auxiliary winding.

[0009] A lighting device according to one aspect of the present disclosure includes the above-mentioned lighting system and the lighting load. Effect of the Invention

[0010] The lighting system and lighting fixture of the present disclosure have the advantage of being able to reduce the size of the circuit for detecting the input AC voltage. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a circuit diagram illustrating a lighting system according to an embodiment of the present disclosure. [Diagram 2]FIG. 2 is a circuit diagram showing an example of a specific configuration of a power conversion circuit included in the lighting system. [Diagram 3] FIG. 3 is a waveform diagram showing waveforms at various parts of the lighting system after AC voltage is applied. [Figure 4] FIG. 4 is a perspective view showing a lighting fixture including the lighting system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following embodiments generally relate to a lighting system and a lighting fixture, and more particularly to a lighting system and a lighting fixture that convert AC power supplied from an AC power source into DC output power and supply the output power to a light source.

[0013] The following embodiment is merely an example of the present disclosure. The present disclosure is not limited to the following embodiment, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0014] The lighting system and the lighting fixture of the present embodiment are used indoors, such as in an office, a factory, a store, a detached house, or a housing complex, or outdoors, such as in a tunnel, a road, or a ground. Note that the place where the lighting system and the lighting fixture of the present embodiment are used is not limited to a specific place.

[0015] Hereinafter, an embodiment will be described with reference to the drawings.

[0016] (Embodiment) (1) Overview of the lighting system FIG. 1 shows a block configuration of a lighting system A1 that lights up a lighting load 9 as a lighting system according to an embodiment.

[0017] The lighting system A1 converts AC power supplied from an AC power source 8 into DC output power, and supplies the output power to a lighting load 9. The lighting system A1 includes a rectifier circuit 1, a power supply circuit 2, a power conversion circuit 3, an auxiliary winding N1, and a power control unit 4.

[0018] The rectifier circuit 1 rectifies an AC voltage Vi of an AC power supply 8 and outputs a rectified voltage V1.

[0019] The power supply circuit 2 has an inductor L2 through which an inductor current IL2 due to a rectified voltage V1 flows, and a switching element Q1 that conducts and cuts off the inductor current IL2, and generates intermediate power by converting the rectified voltage V1 into a DC intermediate voltage V2.

[0020] The power conversion circuit 3 performs a power conversion operation to convert the intermediate power into output power.

[0021] The auxiliary winding N1 is magnetically coupled to the inductor L2.

[0022] The power control unit 4 controls the power conversion operation based on the detection voltage Vd, which is the voltage generated in the auxiliary winding N1.

[0023] In the above-mentioned lighting system A1, the rectified voltage V1 increases as the AC voltage Vi increases. The inductor current IL2 is a current that flows through the inductor L2 by the direct or indirect action of the rectified voltage V1, and the inductor current IL2 increases as the rectified voltage V1 increases. The detection voltage Vd increases as the inductor current IL2 increases. That is, the detection voltage Vd increases as the AC voltage Vi increases, and the detection voltage Vd corresponds to the detection result of the AC voltage Vi. The auxiliary winding N1 does not directly detect the AC voltage Vi, but indirectly detects the AC voltage Vi. It is easy to make the detection voltage Vd generated by the auxiliary winding N1 lower than the AC voltage Vi (rectified voltage V1). Therefore, the withstand voltage performance required for the components such as the auxiliary winding N1 for detecting the AC voltage Vi is relatively low, and the components such as the auxiliary winding N1 can be easily miniaturized, and the number of components can be reduced. As a result, the lighting system A1 can reduce the circuit scale for detecting the input AC voltage Vi.

[0024] (2) Details A lighting system A1 shown in FIG. 1 converts AC power supplied from an AC power supply 8 into DC output power, and supplies the output power to a lighting load 9.

[0025] The lighting load 9 has a plurality of solid-state light-emitting elements. For example, the lighting load 9 has an LED array in which a plurality of LEDs (Light Emitting Diodes) corresponding to a plurality of solid-state light-emitting elements are connected in series. The lighting load 9 is not limited to a configuration having LEDs as solid-state light-emitting elements. The lighting load 9 may have other solid-state light-emitting elements such as organic electroluminescence (OEL) or semiconductor laser diodes (Laser Diodes, LD). The number of solid-state light-emitting elements is not limited to a plurality, and may be one. The electrical connection relationship of the plurality of solid-state light-emitting elements is a series connection, but is not limited to this connection relationship. The electrical connection relationship of the plurality of solid-state light-emitting elements may be a parallel connection, or a combination of a series connection and a parallel connection.

[0026] As shown in FIG. 1, the lighting system A1 includes a rectifier circuit 1, a power supply circuit 2, a power conversion circuit 3, a power control unit 4, a power supply control unit 5, a start-up circuit 6, a detection circuit 7, a pair of input terminals T11, T12, and a pair of output terminals T21, T22.

[0027] (2.1) Rectifier circuit The pair of input terminals T11, T12 are connected to an AC power source 8 and receive an AC voltage Vi. The input terminals T11, T12 are further connected to a rectifier circuit 1. The rectifier circuit 1 includes, for example, a plurality of full-bridge-connected diodes, full-wave rectifies the AC voltage Vi, and outputs a DC rectified voltage V1.

[0028] (2.2) Power supply circuit The power supply circuit 2 includes a SEPIC (Single Ended Primary Inductor Converter) circuit. The SEPIC circuit is a step-up / step-down chopper circuit that converts a DC rectified voltage V1 into a DC intermediate voltage V2.

[0029] The power supply circuit 2 receives the rectified voltage V1 from the rectifier circuit 1 and outputs a DC intermediate voltage V2. The power supply circuit 2 is controlled by a power supply control unit 5.

[0030] Specifically, the power supply circuit 2 includes inductors L1 and L2, capacitors C1 and C2, an output capacitor C3, a diode D1, and a switching element Q1. The inductors L1 and L2 may be wound around the same core, or may be wound around different cores. The capacitor C1 is connected between the output terminals of the rectifier circuit 1, and a rectified voltage V1 is applied between both ends of the capacitor C1. A series circuit is connected between the positive electrode (high potential of the rectified voltage V1) and the negative electrode (low potential of the rectified voltage V1) of the capacitor C1, in which the inductor L1, the capacitor C2, the diode D1, and the output capacitor C3 are connected in this order from the positive electrode of the capacitor C1. The switching element Q1 is connected between the connection point between the inductor L1 and the capacitor C2 and the negative electrode of the capacitor C1. The switching element Q1 is an N-channel enhancement type MOSFET (Metal Oxide Semiconductor Field-Effect Transistor). The drain of the switching element Q1 is connected to the connection point between the inductor L1 and the capacitor C2, and the source of the switching element Q1 is connected to the negative electrode of the capacitor C1. Note that the switching element Q1 may be a semiconductor switching element other than a MOSFET, such as a bipolar transistor.

[0031] An inductor L2 is connected between the connection point between the capacitor C2 and the diode D1 and the negative electrode of the capacitor C1. The voltage across the output capacitor C3 becomes an intermediate voltage V2. The anode of the diode D1 is connected to the capacitor C2, and the cathode of the diode D1 is connected to the positive electrode of the output capacitor C3. The output capacitor C3 is preferably an electrolytic capacitor.

[0032] When the switching element Q1 is turned on, a current flows in the order of the positive output of the rectifier circuit 1 (high potential of the rectified voltage V1), inductor L1, switching element Q1, and negative output of the rectifier circuit 1 (low potential of the rectified voltage V1), and energy (magnetic energy) is stored in the inductor L1. When the switching element Q1 is turned off, charge is stored in the capacitor C2 by the rectified voltage V1, and when the switching element Q1 is turned on, a current (inductor current IL2) flows in the order of the capacitor C2, switching element Q1, inductor L2, and capacitor C2 due to the charge stored in the capacitor C2, and energy (magnetic energy) is stored in the inductor L2. That is, the inductor current IL2 is a current due to the charge stored in the capacitor C2 by the rectified voltage V1, and is a current due to the rectified voltage V1.

[0033] Next, when the switching element Q1 is turned off, the current of the inductor L1 and the inductor current IL2 are cut off, and the output capacitor C3 is charged by the energy stored in the inductors L1 and L2. Also, when the switching element Q1 is turned off, the capacitor C2 is charged by the rectified voltage V1 through the inductor L1.

[0034] Then, by switching on and off at a switching frequency, a step-up / step-down operation is performed using the rectified voltage V1 as an input, and a DC intermediate voltage V2 is generated across the output capacitor C3. A power conversion circuit 3 is connected downstream of the power supply circuit 2, and the power supply circuit 2 outputs the intermediate voltage V2 to the power conversion circuit 3. That is, the power supply circuit 2 generates intermediate power by converting the rectified voltage V1 into the DC intermediate voltage V2, and supplies the intermediate power to the downstream power conversion circuit 3.

[0035] (2.3) Power conversion circuit The power conversion circuit 3 performs a power conversion operation to convert the intermediate power supplied from the power supply circuit 2 into output power, and supplies the output power to the lighting load 9 to light up the lighting load 9.

[0036] Specifically, the power conversion circuit 3 includes a step-down circuit 31 and a power control unit 4.

[0037] The step-down circuit 31 generates a DC output voltage Vo by stepping down the intermediate voltage V2, and outputs the output voltage Vo to a pair of output terminals T21, T22. A lighting load 9 is connected between the output terminals T21, T22, and the output voltage Vo is applied across the lighting load 9. The step-down circuit 31 adjusts the output voltage Vo to adjust the output current Io supplied from the power conversion circuit 3 to the lighting load 9, and turns on the lighting load 9 at a desired dimming level. The step-down circuit 31 has, for example, a step-down chopper circuit. The power conversion operation performed by the step-down circuit 31 includes an oscillation operation of the step-down circuit 31 (step-down chopper circuit). The oscillation operation includes a chopping operation that performs voltage conversion by driving a switching element on and off.

[0038] The power control unit 4 controls (oscillation control) the oscillation operation of the step-down circuit 31. The power control unit 4 causes the step-down circuit 31 to perform an oscillation operation, whereby the step-down circuit 31 generates an output voltage Vo by stepping down the intermediate voltage V2. The power control unit 4 stops the oscillation operation of the step-down circuit 31, whereby the step-down circuit 31 sets the output voltage Vo to zero.

[0039] (2.4) Power supply control section The power supply control unit 5 turns on and off the switching element Q1 of the power supply circuit 2. The power supply control unit 5 controls at least one of the switching frequency and the on-duty of the switching element Q1, thereby controlling the intermediate voltage V2.

[0040] (2.5) Starter circuit The start-up circuit 6 is connected between the output terminals of the rectifier circuit 1 and receives the rectified voltage V1. During a start-up period from when the AC voltage Vi is input to the lighting system A1 until a predetermined time has elapsed, the start-up circuit 6 generates a start-up voltage Vs by stepping down the rectified voltage V1 and outputs the start-up voltage Vs to the power supply control unit 5. During the start-up period, the power supply control unit 5 operates using the start-up voltage Vs as a control voltage Vc and starts turning on and off the switching element Q1 of the power supply circuit 2. That is, during the start-up period, the power supply control unit 5 uses the start-up circuit 6 as a control power supply. As a result, even when the switching of the switching element Q1 has not started in the power supply circuit 2 and a detection voltage Vd described later cannot be used as the control voltage Vc, the power supply control unit 5 can drive the power supply circuit 2 using the start-up voltage Vs as the control voltage Vc.

[0041] (2.6) Detection circuit The detection circuit 7 comprises an auxiliary winding N1 and a diode D2.

[0042] The auxiliary winding N1 is magnetically coupled to the inductor L2 of the power supply circuit 2. A first end of the auxiliary winding N1 is connected to the negative electrode of the capacitor C1. A second end of the auxiliary winding N1 is connected to the anode of the diode D2 and the anode of the diode D11. A cathode of the diode D2 is connected to the power conversion circuit 3. A cathode of the diode D11 is connected to the power supply control unit 5.

[0043] A detection voltage Vd, which is a voltage corresponding to an inductor current IL2 flowing through the inductor L2, is generated across the auxiliary winding N1. The detection voltage Vd is output from the auxiliary winding N1 to the power supply control unit 5 via a diode D11. The detection voltage Vd is also output from the auxiliary winding N1 to the power conversion circuit 3 via a diode D2.

[0044] In the power supply circuit 2, the rectified voltage V1 becomes higher as the AC voltage Vi becomes higher, and becomes lower as the AC voltage Vi becomes lower. The amount of charge stored in capacitor C2 when switching element Q1 is off becomes larger as the rectified voltage V1 becomes higher, and becomes smaller as the rectified voltage V1 becomes lower. When switching element Q1 is on, inductor current IL2 flowing through inductor L2 becomes larger as the amount of charge stored in capacitor C2 becomes larger, and becomes smaller as the amount of charge stored in capacitor C2 becomes smaller. That is, inductor current IL2 depends on AC voltage Vi and rectified voltage V1.

[0045] Therefore, the detection voltage Vd generated by the inductor current IL2 depends on the rectified voltage V1 and the AC voltage Vi. In other words, the magnitude of the detection voltage Vd corresponds to the magnitude of the rectified voltage V1 and the AC voltage Vi.

[0046] When the switching element Q1 of the power supply circuit 2 is turned on and off and an inductor current IL2 flows through the inductor L2, a detection voltage Vd is generated in the auxiliary winding N1. When the detection voltage Vd is generated, the power supply control unit 5 can drive the power supply circuit 2 using the detection voltage Vd input via the diode D11 as a control voltage Vc. That is, the power supply control unit 5 can operate using the detection voltage Vd as the control voltage Vc. Therefore, since the power supply control unit 5 operates using the detection voltage Vd as the control voltage Vc during a steady state, the auxiliary winding N1 can also serve as a control power supply for the power supply control unit 5, and the configuration can be simplified.

[0047] In the power conversion circuit 3, the power control unit 4 receives the detection voltage Vd via the diode D2, determines the magnitude of the AC voltage Vi based on the detection voltage Vd, and controls the operation of the step-down circuit 31 based on the determination result. Hereinafter, the control in the power conversion circuit 3 using the detection voltage Vd will be described.

[0048] (2.7) Control by detection voltage In the power conversion circuit 3, the power control unit 4 receives the detection voltage Vd via the diode D2. The power control unit 4 determines whether the magnitude of the AC voltage Vi is outside a predetermined range based on the detection voltage Vd, and stops the power conversion operation of the step-down circuit 31 if it determines that the magnitude of the AC voltage Vi is outside the predetermined range.

[0049] Specifically, the power control unit 4 calculates the effective value of the detected voltage Vd. Since the effective value of the detected voltage Vd corresponds to the magnitude of the AC voltage Vi, the power control unit 4 can monitor the magnitude of the AC voltage Vi by monitoring the effective value of the detected voltage Vd. By obtaining the effective value of the detected voltage Vd as the magnitude of the AC voltage Vi, the power control unit 4 can easily determine the magnitude of the AC voltage Vi with high accuracy.

[0050] The power control unit 4 holds in advance data on a lower limit threshold and an upper limit threshold as threshold data to be compared with the effective value of the detection voltage Vd. The range between the lower limit threshold and the upper limit threshold corresponds to the above-mentioned predetermined range. If the effective value of the detection voltage Vd is between the lower limit threshold and the upper limit threshold, the power control unit 4 determines that the AC voltage Vi is normal and allows the step-down circuit 31 to continue the oscillation operation. If the effective value of the detection voltage Vd falls below the lower limit threshold, the power control unit 4 determines that a dip or momentary interruption has occurred in the AC voltage Vi and stops the oscillation operation of the step-down circuit 31. If the effective value of the detection voltage Vd exceeds the upper limit threshold, the power control unit 4 determines that an overvoltage abnormality has occurred in the AC voltage Vi and stops the oscillation operation of the step-down circuit 31.

[0051] Therefore, abnormal operation and failure of the lighting system A1 can be prevented, and the reliability of the lighting system A1 is improved.

[0052] In addition, after stopping the oscillation operation of the step-down circuit 31, the power control unit 4 may automatically resume the oscillation operation of the step-down circuit 31 if the effective value of the detection voltage Vd returns to a range of not less than the lower threshold value and not more than the upper threshold value, or may resume the oscillation operation of the step-down circuit 31 after a reset operation by the user.

[0053] In addition, when the effective value of the detected voltage Vd fluctuates, the power control unit 4 may determine that the magnitude of the AC voltage Vi is fluctuating, and control the oscillation operation of the step-down circuit 31 so as to suppress flickering of the lighting load 9 caused by the fluctuation of the AC voltage Vi.

[0054] 2 shows an example of a specific configuration of the power conversion circuit 3. In the power conversion circuit 3, the step-down circuit 31 includes a step-down integrated circuit (IC) 311, and the power control unit 4 includes a microcontroller 41. The power conversion circuit 3 further includes an inductor L31 and a resistor R31.

[0055] The microcontroller 41 has an arithmetic unit such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), and a storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory). A program is stored in the storage device, and the arithmetic unit reads out the program stored in the storage device and executes the program to control the oscillation operation of the step-down IC 311. That is, the power control unit 4 includes the microcontroller 41 that controls the power conversion operation by executing a program. The microcontroller 41 operates by generating a control voltage for the microcontroller 41 from the intermediate voltage V2.

[0056] In the power control unit 4, the control contents of the step-down IC 311 by the microcontroller 41 can be changed by rewriting the program stored in the storage device. Therefore, compared to a case where the power control unit 4 is configured only with hardware, the lighting control of the lighting load 9 can be changed flexibly, improving the versatility of the lighting system A1. For example, the control contents of the step-down IC 311 (e.g., target current value, target voltage value, etc.) can be easily changed according to the rated power, rated voltage, etc. of the lighting load 9.

[0057] The step-down IC311 is an integrated circuit that constitutes a step-down chopper circuit having elements such as a switching element, a resistor, a capacitor, and an inductor, and is driven and controlled by the microcontroller 41. The step-down IC311 generates a direct current output voltage Vo by stepping down the intermediate voltage V2. An inductor L31 is connected between the positive output terminal of the step-down IC311 and the output terminal T21, and the step-down IC311 outputs the output voltage Vo through a pair of output terminals T21 and T22. The step-down IC311 adjusts the output current Io by adjusting the output voltage Vo, and lights up the lighting load 9 at a desired dimming level. In FIG. 2, a resistor R31 is connected in series to the output terminal T22, and a voltage proportional to the output current Io is generated across the resistor R31. The microcontroller 41 obtains the voltage across the resistor R31, and adjusts the output voltage Vo so that the voltage across the resistor R31 matches the target voltage value, thereby matching the output current Io to the target current value.

[0058] The detection voltage Vd is also input to the microcontroller 41 via the diode D2. The microcontroller 41 calculates the effective value of the detection voltage Vd, and continues or stops the oscillation operation of the step-down circuit 31 based on the effective value of the detection voltage Vd. However, there is an unstable period during which the detection voltage Vd becomes unstable after the AC voltage Vi is input to the lighting system A1 until the operation of the lighting system A1 becomes stable. During this unstable period, it is preferable that the microcontroller 41 does not control the oscillation of the step-down IC 311 based on the effective value of the detection voltage Vd.

[0059] Fig. 3 shows waveforms at each part after the AC voltage Vi is applied. Fig. 3 shows waveforms of the AC voltage Vi, the output current Io, the detection voltage Vd, and the control voltage Vc of the power supply control unit 5.

[0060] When the AC voltage Vi is applied at time t1, the power supply control unit 5 starts up using the start-up voltage Vs as a control voltage Vc, and starts the on-off drive of the switching element Q1 of the power supply circuit 2 at time t2. When the switching element Q1 is on-off driven and a detection voltage Vd is generated in the auxiliary winding N1, the power supply control unit 5 operates using the detection voltage Vd as a control voltage Vc, and continues the on-off drive of the switching element Q1. When the switching element Q1 is on-off driven, the power supply circuit 2 outputs an intermediate voltage V2. At time t3, the microcontroller 41 starts up by generating a control voltage for the microcontroller 41 from the intermediate voltage V2, and starts the oscillation operation of the step-down IC 311. When the step-down IC 311 starts the oscillation operation, the step-down IC 311 generates an output voltage Vo and increases the output current Io supplied to the lighting load 9 to a target current value Io1.

[0061] Here, the detection voltage Vd is unstable from time t1 when the AC voltage Vi is applied until immediately after time t3 when the microcontroller 41 starts up. Therefore, the timing when a certain amount of time has elapsed from time t3 is defined as time t4, and the period from time t1 to t4 is defined as an unstable period W1 during which the detection voltage Vd is likely to become unstable. The period after time t4 is defined as a stable period W2 during which the detection voltage Vd is stable.

[0062] The microcontroller 41 sets the period from startup at time t3 to time t4 as a mask period Wm. During the mask period Wm, the microcontroller 41 masks the input of the detection voltage Vd and treats the detection voltage Vd as a predetermined normal value (a value equal to or greater than a lower threshold and equal to or less than an upper threshold). That is, during the mask period Wm, the microcontroller 41 stops the oscillation control of the step-down circuit 31 based on the effective value of the detection voltage Vd.

[0063] As described above, the power control unit 4 stops controlling the power conversion operation based on the magnitude of the detected voltage Vd during the mask period Wm from when the microcontroller 41 (power control unit 4) is started until a predetermined time has elapsed. Therefore, it is possible to prevent the power conversion operation from being controlled based on the unstable detected voltage Vd during the unstable period W1 immediately after the AC voltage Vi is input to the lighting system A1. As a result, it is possible to prevent malfunctions and improve the accuracy of the detected voltage Vd, thereby improving reliability.

[0064] (3) Lighting equipment 4 shows a lighting fixture B1 as an example of a lighting fixture including the lighting system A1. The lighting fixture B1 includes a light source unit 101 and a housing 102 that supports the light source unit 101.

[0065] The light source unit 101 has a long box-shaped outer shell and houses the lighting load 9 inside the shell. The lighting load 9 has, for example, a long board and a number of LEDs (Light Emitting Diodes) mounted on the board in a line along the longitudinal direction. The housing 102 has a long shape and houses the lighting system A1 inside the housing 102. The light source unit 101 is supported on one side of the housing 102, and the lighting system A1 and the lighting load 9 are connected. The housing 102 also has a pair of reflectors 103 that protrude obliquely upward from both side edges of the light source unit 101 along the longitudinal direction.

[0066] By including the lighting system A1, the lighting fixture B1 can reduce the size of the circuit for detecting the input AC voltage Vi.

[0067] (4) Variations The auxiliary winding N1 may be magnetically coupled to inductor L1 instead of inductor L2 (see FIG. 1).

[0068] The power control unit 4 may calculate the average value or peak value of the detected voltage Vd instead of the effective value of the detected voltage Vd. In this case, the power control unit 4 determines whether the average value or peak value of the detected voltage Vd is outside a predetermined range.

[0069] The power supply circuit 2 may be configured with a circuit other than the SEPIC circuit, and may be configured with any of, for example, a CUK circuit, a ZETA circuit, a step-up chopper circuit, a step-down chopper circuit, and a step-up / step-down chopper circuit, etc. In other words, the power supply circuit 2 only needs to have an inductor through which an inductor current due to the rectified voltage V1 flows, and a switching element that conducts and cuts off the inductor current.

[0070] The power conversion circuit 3 is not limited to a configuration including the step-down circuit 31, and may include a step-up circuit, a step-up / step-down circuit, a constant current circuit, or the like instead of the step-down circuit 31.

[0071] The power control unit 4 may be configured separately from the power conversion circuit 3. Moreover, the power control unit 4 and the power supply control unit 5 may be configured integrally.

[0072] The lighting system A1 may be a lighting device in which each component constituting the lighting system A1 is housed in a single housing, or may be configured in such a way that each component constituting the lighting system A1 is distributed.

[0073] The lighting fixture including the lighting system A1 may be any lighting fixture other than the lighting fixture B1 (see FIG. 4), such as a downlight, a ceiling light, a pendant light, or a spotlight.

[0074] (5) Summary A lighting system (A1) according to a first aspect of the embodiment converts AC power supplied from an AC power source (8) into DC output power and supplies the output power to a lighting load (9). The lighting system (A1) includes a rectifier circuit (1), a power supply circuit (2), a power conversion circuit (3), an auxiliary winding (N1), and a power control unit (4). The rectifier circuit (1) rectifies an AC voltage (Vi) from the AC power source (8) and outputs a rectified voltage (V1). The power supply circuit (2) has an inductor (L2) through which an inductor current (IL2) due to the rectified voltage (V1) flows, and a switching element (Q1) that conducts and cuts off the inductor current (IL2), and generates intermediate power by converting the rectified voltage (V1) into a DC intermediate voltage (V2). The power conversion circuit (3) performs a power conversion operation to convert the intermediate power into output power. The auxiliary winding (N1) is magnetically coupled to the inductor (L2). The power control unit (4) controls the power conversion operation based on the detected voltage (Vd), which is the voltage generated in the auxiliary winding (N1).

[0075] In the above-mentioned lighting system (A1), the withstand voltage performance required for components such as the auxiliary winding (N1) for detecting the AC voltage (Vi) is relatively low, and components such as the auxiliary winding (N1) can be easily miniaturized and the number of components can be reduced. As a result, the lighting system (A1) can reduce the circuit scale for detecting the input AC voltage (Vi).

[0076] In the lighting system (A1) of the second aspect of the embodiment, in the first aspect, it is preferable that the power control unit (4) determines whether or not the magnitude of the AC voltage (Vi) is outside a predetermined range based on the detected voltage (Vd). If the power control unit (4) determines that the magnitude of the AC voltage (Vi) is outside the predetermined range, it stops the power conversion operation.

[0077] The above-described lighting system (A1) can prevent abnormal operation, failure, and the like of the lighting system (A1) from occurring, and the reliability of the lighting system (A1) is improved.

[0078] In the lighting system (A1) of the third aspect of the embodiment, in the first or second aspect, the power control unit (4) preferably obtains an effective value of the detected voltage (Vd) as the magnitude of the detected voltage (Vd). The power control unit (4) controls the power conversion operation based on the effective value of the detected voltage (Vd).

[0079] The above-described lighting system (A1) can easily determine the magnitude of the AC voltage (Vi) with high accuracy.

[0080] In the lighting system (A1) of the fourth aspect of the embodiment, in any one of the first to third aspects, it is preferable that the lighting system (A1) further includes a power supply control unit (5) that controls the power supply circuit (2). The power supply control unit (5) operates using the detection voltage (Vd) as a control voltage (Vc).

[0081] The lighting system (A1) described above can simplify the configuration of the control power supply for the power supply control unit (5).

[0082] In the lighting system (A1) of the fifth aspect of the embodiment, in any one of the first to fourth aspects, it is preferable that the power control unit (4) includes a microcontroller (41) that controls the power conversion operation by executing a program.

[0083] The lighting system (A1) described above can flexibly change the lighting control of the lighting load (9), improving the versatility of the lighting system (A1).

[0084] In the lighting system (A1) of the sixth aspect of the embodiment, in any one of the first to fifth aspects, it is preferable that the power control unit (4) stops control of the power conversion operation based on the magnitude of the detected voltage (Vd) during a mask period (Wm) from when the power control unit (4) is started until a predetermined time has elapsed.

[0085] The above-described lighting system (A1) can suppress malfunctions and improve the accuracy of the detection voltage (Vd), thereby improving reliability.

[0086] In the lighting system (A1) of the seventh aspect according to the embodiment, in any one of the first to sixth aspects, it is preferable that the power conversion operation includes an oscillation operation of the power conversion circuit (3).

[0087] The above-described lighting system (A1) can easily control the output power by controlling the oscillation operation of the power conversion circuit (3).

[0088] In the lighting system (A1) of the eighth aspect according to the embodiment, in any one of the first to seventh aspects, it is preferable that the power supply circuit (2) includes a SEPIC circuit.

[0089] The above-described lighting system (A1) can easily realize acquisition of the detection voltage (Vd) by the auxiliary winding (N1).

[0090] A lighting device (B1) according to a ninth aspect of the present embodiment includes a lighting system (A1) according to any one of the first to eighth aspects and a lighting load (9).

[0091] The lighting fixture (B1) described above can reduce the circuit scale for detecting the input AC voltage (Vi). [Explanation of symbols]

[0092] A1 Lighting System B1 Lighting equipment 1 Rectifier circuit 2 Power circuit 3 Power Conversion Circuit 4. Power control section 41 Microcontrollers 5 Power supply control section 8 AC power supply 9 Lighting Load N1 Auxiliary Winding L2 inductor Q1 Switching element Vi AC voltage V1 Rectified voltage V2 Intermediate voltage Vd Detection voltage Vc Control voltage IL2 Inductor current Wm Mask Period

Claims

1. A lighting system that converts AC power supplied from an AC power source into DC output power and supplies the output power to a lighting load, a rectifier circuit that rectifies the AC voltage of the AC power supply and outputs a rectified voltage; a power supply circuit including an inductor through which an inductor current flows due to the rectified voltage and a switching element that turns on and off the inductor current, and that generates intermediate power by converting the rectified voltage into a DC intermediate voltage; a power conversion circuit that performs a power conversion operation to convert the intermediate power into the output power; an auxiliary winding magnetically coupled to the inductor; a power control unit that controls the power conversion operation based on a detection voltage that is a voltage generated in the auxiliary winding. Lighting system.

2. The power control unit is determining whether the magnitude of the AC voltage is outside a predetermined range based on the detected voltage; If it is determined that the magnitude of the AC voltage is outside the predetermined range, the power conversion operation is stopped. The lighting system of claim 1.

3. The power control unit is The effective value of the detected voltage is calculated as the magnitude of the detected voltage; The power conversion operation is controlled based on the effective value of the detected voltage. The lighting system of claim 1.

4. A power supply control unit that controls the power supply circuit is further provided. The power supply control unit operates using the detected voltage as a control voltage. The lighting system of claim 1.

5. The power control unit includes a microcontroller that executes a program to control the power conversion operation. The lighting system of claim 1.

6. The power control unit stops control of the power conversion operation based on the magnitude of the detected voltage during a mask period from when the power control unit is started until a predetermined time has elapsed. The lighting system of claim 1.

7. The power conversion operation includes an oscillation operation of the power conversion circuit. The lighting system of claim 1.

8. The power supply circuit includes a SEPIC circuit. The lighting system of claim 1.

9. A lighting system according to any one of claims 1 to 8; The lighting load. Lighting fixtures.

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