US20180235058A1 - Lighting device and luminaire - Google Patents
Lighting device and luminaire Download PDFInfo
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- US20180235058A1 US20180235058A1 US15/878,116 US201815878116A US2018235058A1 US 20180235058 A1 US20180235058 A1 US 20180235058A1 US 201815878116 A US201815878116 A US 201815878116A US 2018235058 A1 US2018235058 A1 US 2018235058A1
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- power supply
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- H05B37/0272—
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
- H05B47/175—Controlling the light source by remote control
- H05B47/19—Controlling the light source by remote control via wireless transmission
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- H05B37/0281—
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
- H05B47/16—Controlling the light source by timing means
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/20—Responsive to malfunctions or to light source life; for protection
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Definitions
- the present disclosure relates to a lighting device which supplies DC power to a light emitting element, and a luminaire.
- Luminaires which can be remotely operated by a remote control or the like are conventionally known (see, Japanese Unexamined Patent Application Publication No. 2013-70617, for example).
- the luminaire disclosed by Japanese Unexamined Patent Application Publication No. 2013-70617 includes a dimming signal input circuit to which a dimming signal transmitted from a remote control or the like is input.
- the dimming signal input circuit outputs to a switching circuit a signal corresponding to the dimming signal.
- the switching circuit controls a switching element at a duty ratio corresponding to the dimming signal. In this manner, it is possible to remotely operate a dimming level of the luminaire.
- a control circuit such as a dimming signal input circuit is implemented by an integrated circuit such as a micro-controller unit (MCU), for example.
- MCU micro-controller unit
- DC power resulting from rectifying and stepping-down AC power supplied from an AC power supply is used in operations of such an integrated circuit.
- power supply to the integrated circuit is interrupted by turning off a main power switch of the luminaire.
- a voltage supplied to the integrated circuit falls below an operation voltage, there could be the case where the integrated circuit is placed to an undefined state, and thus not be able to operate normally.
- a reset function is provided to an integrated circuit. For example, when a voltage supplied to the integrated circuit becomes lower than or equal to a reset voltage that is set to a value lower than an operation voltage, the integrated circuit is reset. In this manner, when power supply to the integrated circuit is resumed, the integrated circuit is able to operate normally.
- an object of the present disclosure is to provide a lighting device and a luminaire with which it is possible to suppress occurrence of operation failure in a control circuit.
- a lighting device which causes a light emitting element to emit light.
- the lighting device includes: a DC power supply which converts AC power to DC power; a first lighting control circuit which adjusts a value of a current supplied to the light emitting element, by controlling the DC power supply; a second lighting control circuit which controls the first lighting control circuit; a first control power supply which supplies a first voltage to the first lighting control circuit; a second control power supply to which the first voltage is supplied and which supplies a second voltage to the second lighting control circuit; and a reset circuit which (i) when the reset circuit detects that the first voltage decreases to a first threshold or lower, causes the second control power supply to stop supply of the second voltage, and (ii) when the reset circuit detects that the first voltage increases to a second threshold or higher and that the second voltage is higher than a third threshold, causes the second control power supply to start supply of the second voltage after the second voltage decreases to the third threshold or lower.
- a luminaire according to an aspect of the present disclosure includes the above-described lighting device and the above-described light emitting element.
- FIG. 1 is a block diagram which illustrates a functional configuration of a lighting device according to Embodiment 1;
- FIG. 2 is a circuit diagram which illustrates another example of a circuit configuration of a control power supply according to Embodiment 1;
- FIG. 3 is a flowchart which illustrates an operation of the lighting device according to Embodiment 1;
- FIG. 4 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in the lighting device according to Embodiment 1;
- FIG. 5 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in a lighting device according to a comparison example
- FIG. 6 is a block diagram which illustrates a functional configuration of a lighting device according to Embodiment 2;
- FIG. 7 is a flowchart which illustrates an example of an operation of the lighting device according to Embodiment 2;
- FIG. 8 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in the lighting device according to Embodiment 2;
- FIG. 9 is a flowchart which illustrates another example of an operation of the lighting device according to Embodiment 2;
- FIG. 10A is an external view of an example of a luminaire which includes the lighting device according to each of the embodiments.
- FIG. 10B is an external view of another example of a luminaire which includes the lighting device according to each of the embodiments.
- each diagram is a schematic diagram and not necessarily strictly illustrated.
- the same numerical sign is given to identical structural components.
- Embodiment 1 descries a lighting device according to Embodiment 1.
- FIG. 1 is a block diagram which illustrates a functional configuration of lighting device 10 according to the present embodiment. It should be noted that, in FIG. 1 , AC power supply 2 which supplies power to lighting device 10 , light emitting element 4 to which power is supplied from lighting device 10 , and remote control 80 which remotely operates lighting device 10 are illustrated together with lighting device 10 .
- AC power supply 2 is a power supply which supplies AC power to lighting device 10 .
- AC power supply 2 is a system power supply such as a commercial AC power supply.
- Light emitting element 4 is a light source to which lighting device 10 supplies power. Light emitting element 4 only needs to be a light source which emits light as a result of being supplied with DC power, and is not specifically limited.
- light emitting element 4 is a solid-state light emitting element such as a light emitting diode (LED).
- Remote control 80 is a controller for remotely operating lighting device 10 .
- Remote control 80 for example, performs turning on, turning off, and dimming of light emitting element 4 , by controlling lighting device 10 .
- Remote control 80 may be a dedicated controller of lighting device 10 , or may be a general mobile terminal such as a smartphone.
- Lighting device 10 is a device to which AC power is supplied, and which supplies DC power to light emitting element 4 . As illustrated in FIG. 1 , lighting device 10 includes DC power supply 20 , control power supply 30 , first lighting control circuit 41 , and second lighting control circuit 42 .
- DC power supply 20 is a power supply circuit which converts AC power to DC power.
- DC power supply 20 includes diode bridge 22 , boost converter 24 , and step-down converter 26 .
- DC power supply 20 only needs to be a power supply circuit which converts AC power to DC power.
- DC power supply 20 may include a flyback converter, a buck-boost converter, etc.
- Diode bridge 22 is a circuit which rectifies AC power supplied from AC power supply 2 .
- Boost converter 24 is a circuit which boosts a voltage output from diode bridge 22 .
- Boost converter 24 includes, for example, a switching element such as a metal-oxide semiconductor field-effect transistor (MOSFET), etc.
- MOSFET metal-oxide semiconductor field-effect transistor
- the switching element included in boost converter 24 is controlled by first lighting control circuit 41 .
- Boost converter 24 for example, boosts a voltage of approximately 100 V output from diode bridge 22 to a voltage of approximately 200 V.
- Step-down converter 26 is a power supply circuit which steps down a voltage output from boost converter 24 , and supplies the stepped down voltage to light emitting element 4 .
- Step-down converter 26 includes, for example, a switching element such as a MOSFET. The switching element included in step-down converter 26 is controlled by first lighting control circuit 41 .
- Step-down converter 26 for example, steps down a voltage of approximately 200 V output from boost converter 24 , to a voltage suitable for light emitting element 4 .
- First lighting control circuit 41 is a circuit which adjusts a value of a current to be supplied to light emitting element 4 , by controlling DC power supply 20 .
- First lighting control circuit 41 controls DC power supply 20 , by outputting, for example, corresponding pulse width modulation (PWM) signals to a switching element of each of boost converter 24 and step-down converter 26 of DC power supply 20 .
- Power for causing first lighting control circuit 41 to operate is supplied from control power supply 30 .
- First lighting control circuit 41 is implemented by a micro-controller unit, for example.
- a microcomputer is a single-chip semiconductor integrated circuit which includes a ROM in which a program is stored, a RAM, a processor (central processing unit (CPU)) which executes a program, a timer, an input and output circuit including an A/D converter and a D/A converter, etc.
- Second lighting control circuit 42 is a circuit which controls first lighting control circuit 41 .
- second lighting control circuit 42 includes a wireless communication integrated circuit which outputs, to first lighting control circuit 41 , an instruction signal for instructing turning on, turning off, or dimming of light emitting element 4 , according to an input signal from outside.
- the wireless communication integrated circuit is implemented by a micro-controller unit, as with first lighting control circuit 41 .
- Second lighting control circuit 42 receives an input signal from a controller such as remote control 80 . Power for causing second lighting control circuit 42 to operate is supplied from control power supply 30 .
- the wireless communication integrated circuit included by second lighting control circuit 42 has, for example, an operation voltage lower limit of 1.8 V.
- the wireless communication integrated circuit is reset when a voltage lower than or equal to a reset voltage of 1.0 V is supplied. Accordingly, the wireless communication integrated circuit operates normally when a voltage of higher than or equal to 1.8 V is supplied.
- the wireless communication integrated circuit is reset when a voltage lower than or equal to 1.0 V is supplied, and is capable of operating normally at the time of reactivation (i.e., at the time when a voltage higher than or equal to the operation voltage lower limit is supplied next time).
- the wireless communication integrated circuit is placed to an undefined state when a voltage higher than the reset voltage (1.0 V) and lower than the operation voltage lower limit (1.8 V) is supplied. In other words, the wireless communication integrated circuit is placed in a state in which a normal operation is not secured. It should be noted that the wireless communication integrated circuit does not have a function of being reset forcibly from outside.
- Control power supply 30 is a power supply circuit which generates a first voltage and a second voltage for causing first lighting control circuit 41 and second lighting control circuit 42 , respectively, to operate.
- Control power supply 30 includes first control power supply 31 , second control power supply 32 , and reset circuit 50 .
- First control power supply 31 is a power supply circuit which supplies a first voltage to first lighting control circuit 41 .
- First control power supply 31 only needs to be a circuit which outputs the first voltage, and the configuration of first control power supply 31 is not specifically limited.
- first control power supply is a step-down converter to which an output voltage from boost converter 24 is input, and which steps down the output voltage.
- first control power supply 31 steps down the output voltage of approximately 200 V from boost converter 24 to be a first voltage of 5V.
- First control power supply 31 supplies the first voltage to second control power supply 32 .
- Second control power supply 32 is a power supply circuit to which the first voltage is supplied by first control power supply 31 , and which supplies a second voltage to second lighting control circuit 42 .
- Second control power supply 32 only needs to be a circuit to which the first voltage is supplied, and which outputs the second voltage, and the configuration of second control power supply 32 is not specifically limited.
- second control power supply 32 is a three-terminal regulator.
- second control power supply 32 steps down the first voltage of 5 V to a second voltage of 3V.
- starting and stopping of an operation of second control power supply 32 , and a delay time for starting supply of a second voltage by second control power supply 32 are controlled by reset circuit 50 .
- Reset circuit 50 is a circuit which monitors the first voltage and controls an operation of second control power supply 32 according to the first voltage, thereby suppressing occurrence of operation failure in second lighting control circuit 42 . More specifically, reset circuit 50 causes second control power supply 32 to stop supply of the second voltage, when reset circuit 50 detects that the first voltage decreases from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 .
- reset circuit 50 when (i) reset circuit 50 detects that the first voltage increases from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 , and (ii) the second voltage is higher than the third threshold, reset circuit 50 causes second control power supply 32 to start supply of the second voltage after the second voltage decreases to the third threshold or lower.
- first threshold Vth 1 and second threshold Vth 2 are each a value higher than or equal to the operation voltage lower limit of the wireless communication integrated circuit included in second lighting control circuit 42 .
- first threshold Vth 1 and second threshold Vth 2 are each 2.4 V, for example.
- first threshold Vth 1 and second threshold Vth 2 are the same value according to the present embodiment, first threshold Vth 1 and second threshold Vth 2 may be values different from each other.
- first threshold Vth 1 may be set to 2.3 V and second threshold Vth 2 may be set to 2.5 V, and control in reset circuit 50 may implement hysteresis.
- the third threshold is a value lower than or equal to a reset voltage (1.0 V) of the wireless communication integrated circuit of second lighting control circuit 42 .
- the reset voltage is the third threshold. Details of the operations performed by reset circuit 50 will be given later.
- Reset circuit 50 includes monitoring circuit 34 and delay circuit 36 .
- Monitoring circuit 34 is a circuit which monitors the first voltage, and controls second control power supply 32 according to the first voltage. Monitoring circuit 34 outputs a control signal for causing second control power supply 32 to stop supply of the second voltage, when monitoring circuit 34 detects that the first voltage decreases from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 . In addition, monitoring circuit 34 outputs a control signal for causing second control power supply 32 to start supply of the second voltage, when monitoring circuit 34 detects that the first voltage increases from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 .
- Delay circuit 36 is a circuit which delays the start of supply of the second voltage by second control power supply 32 .
- delay circuit 36 delays the start of supply of the second voltage from when a control signal for causing second control power supply 32 to start supply of the second voltage is input by monitoring circuit 34 to when first delay time Td 1 passes.
- delay circuit 36 may cause the supply of the second voltage to be started when first delay time Td 1 passes after the control signal is received by second control power supply 32 , or may cause an output of the control signal from monitoring circuit 34 to second control power supply 32 to be delayed.
- First delay time Td 1 is, for example, longer than or equal to approximately 50 msec and shorter than or equal to approximately 300 msec. More preferably, first delay time Td 1 is longer than or equal to approximately 80 msec and shorter than or equal to approximately 200 msec. Details of first delay time Td 1 will be given later.
- Monitoring circuit 34 and delay circuit 36 included in reset circuit 50 can be implemented by combining, for example, elements such as a comparator, a transistor, a capacitor, etc. It should be noted that the first voltage monitored by monitoring circuit 34 may be supplied to reset circuit 50 for causing reset circuit 50 to operate.
- the circuit configuration of reset circuit 50 is not limited to the circuit configuration illustrated in FIG. 1 .
- one of monitoring circuit 34 and delay circuit 36 included in reset circuit 50 may be implemented by a single integrated circuit. An example of such a circuit configuration will be described with reference to FIG. 2 .
- FIG. 2 is a circuit diagram which illustrates another example of the circuit configuration of control power supply 30 according to the present embodiment. It should be noted that, in FIG. 2 , second lighting control circuit 42 is also illustrated together with control power supply 30 . As illustrated in FIG. 2 , control power supply 30 includes reset circuit 50 , first control power supply 31 , and second control power supply 32 which are implemented by a single integrated circuit. Control power supply 30 further includes capacitors 44 , 52 , and 54 . Capacitors 54 and 44 are elements for stabilizing the first voltage output from first control power supply 31 and the second voltage output from second control power supply 32 , respectively. Capacitor 52 is an element for adjusting first delay time Td 1 .
- the first voltage output from output terminal OUT of first control power supply 31 is input to each of input terminals IN of reset circuit 50 and second control power supply 32 . It should be noted that, although not illustrated in FIG. 2 , the first voltage is also input to first lighting control circuit 41 .
- Reset circuit 50 outputs a control signal for controlling a start and a stop of the supply of the second voltage, from output terminal OUT to control terminal TC of second control power supply 32 . In the example illustrated in FIG.
- a control signal for instructing a start of supply of the second voltage is output from output terminal OUT of reset circuit 50 , when first delay time Td 1 passes from a time point when reset circuit 50 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 .
- first delay time Td 1 passes from a time point when reset circuit 50 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 .
- FIG. 3 is a flowchart which illustrates an operation of lighting device 10 according to the present embodiment.
- FIG. 4 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage in lighting device 10 according to the present embodiment.
- an operation of lighting device 10 is started as illustrated in FIG. 3 (at time point T 1 and at time point T 6 in FIG. 4 ).
- the first voltage output from first control power supply 31 increases (from time point T 1 to time point T 2 , and from time point T 6 to time point T 7 in FIG. 4 ).
- Monitoring circuit 34 of reset circuit 50 in lighting device 10 monitors the first voltage, and determines whether or not an increase from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 is detected in the first voltage (S 11 ).
- monitoring circuit 34 When monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 (YES in S 11 ), monitoring circuit 34 causes second control power supply 32 to start supply of the second voltage when first delay time Td 1 passes from a time point of the detection (S 12 ).
- monitoring circuit 34 outputs a control signal for causing second control power supply 32 to start supply of the second voltage.
- Second control power supply 32 starts supply of the second voltage at time point T 3 and time point T 8 when first delay time Td 1 determined by delay circuit 36 passes from time point T 2 and time point T 7 when the control signal is received.
- first delay time Td 1 is a period of time longer than or equal to a period of time required for the second voltage to decrease from the operation voltage lower limit (1.8 V) of the wireless communication integrated circuit of second lighting control circuit 42 to a reset voltage (1.0 V) when second control power supply 32 causes the supply of the second voltage to be stopped.
- second control power supply 32 receives an instruction for resuming the supply of the second voltage
- the second voltage is lower than or equal to the reset voltage of the wireless communication integrated circuit.
- the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state that is (i) lower than the operation voltage lower limit of the wireless communication integrated circuit and (ii) higher than the reset voltage, thereby reliably resetting the wireless communication integrated circuit at time point T 8 . Accordingly, it is possible to suppress occurrence of control failure in the wireless communication integrated circuit.
- Step S 12 the operation proceeds to Step S 13 .
- Step S 11 monitoring circuit 34 does not detect an increase from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 in the first voltage (NO in S 11 )
- the operation returns to Step S 11 .
- monitoring circuit 34 performs determination as described above in a period from time point T 1 to immediately before time point T 2 , and a period from time point T 6 to immediately before time point T 7 .
- monitoring circuit 34 continues monitoring of the first voltage, and determines whether or not a decrease from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 is detected in the first voltage (S 13 ).
- monitoring circuit 34 When monitoring circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 (YES in S 13 ), monitoring circuit 34 causes second control power supply 32 to stop the supply of the second voltage (S 14 ).
- the first voltage output from first control power supply 31 starts to decrease due to, for example, a stop of power supply from AC power supply 2 at time point T 4 , and the first voltage reaches first threshold Vth 1 at time point T 5 . Accordingly, at time point T 5 , monitoring circuit 34 outputs a control signal for causing second control power supply 32 to stop the supply of the second voltage. Subsequent to Step S 14 , the operation returns to Step S 11 .
- monitoring circuit 34 when monitoring circuit 34 does not detect that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 (NO in S 13 ), monitoring circuit 34 does not cause second control power supply 32 to stop the supply of the second voltage, and the operation returns to Step S 13 .
- monitoring circuit 34 performs determination as described above in a period from time point T 3 to time point T 4 , for example.
- Lighting device 10 repeats the above-described processes from Step S 11 to Step S 14 .
- lighting device 10 is capable of suppressing occurrence of control failure in the wireless communication integrated circuit of second lighting control circuit 42 .
- an operation example of a lighting device according to a comparison example will be described with reference to FIG. 5 .
- FIG. 5 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage in a lighting device according to the comparison example.
- the lighting device according to the comparison example has a configuration same as the configuration of lighting device 10 according to the present embodiment, other than that the lighting device according to the comparison example does not include reset circuit 50 .
- the first voltage starts to increase, and the second voltage also starts to increase along with the increase of the first voltage.
- the first voltage starts to decrease, and the second voltage also starts to decrease along with the decrease of the first voltage.
- the first voltage starts to increase, and the second voltage also starts to increase at time point T 14 immediately after time point T 13 and exceeds the operation voltage lower limit of the wireless communication integrated circuit.
- the second voltage is lower than the operation voltage lower limit (1.8 V) of the wireless communication integrated circuit and higher than the reset voltage (1.0 V), as illustrated in FIG. 5 .
- the wireless communication integrated circuit is supplied with the second voltage higher than or equal to the operation voltage lower limit, without being reset from the undefined state. Accordingly, control failure could occur in the wireless communication integrated circuit.
- the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state as described above.
- the wireless communication integrated circuit is reliably reset. For that reason, with lighting device 10 , it is possible to suppress occurrence of control failure more reliably than the lighting device according to the comparison example.
- first delay time Td 1 may be longer than an unstable time taken from a start of DC power supply 20 until an operation is stabilized.
- that the operation of DC power supply 20 is stabilized indicates, for example, the state in which a variation width of an output voltage of DC power supply 20 is less than or equal to 5%.
- the wireless communication integrated circuit of second lighting control circuit 42 is activated after the operations of first lighting control circuit 41 and DC power supply 20 are stabilized, it is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start of DC power supply 20 .
- the unstable time is approximately 100 msec, for example.
- lighting device 10 is a device which causes light emitting element 4 to emit light.
- Lighting device 10 includes: DC power supply 20 which converts AC power to DC power; first lighting control circuit 41 which adjusts a value of a current supplied to light emitting element 4 by controlling DC power supply 20 ; and second lighting control circuit 42 which controls first lighting control circuit 41 .
- Lighting device 10 further includes: first control power supply 31 which supplies a first voltage to first lighting control circuit 41 ; second control power supply 32 to which the first voltage is supplied and which supplies a second voltage to second lighting control circuit 42 ; and reset circuit 50 .
- Reset circuit 50 when reset circuit 50 detects that the first voltage decreases to a first threshold or lower, causes second control power supply 32 to stop supply of the second voltage.
- reset circuit 50 when reset circuit 50 detects that the first voltage increases to a second threshold or higher and that the second voltage is higher than a third threshold, causes second control power supply 32 to start supply of the second voltage after the second voltage decreases to the third threshold or lower.
- the third threshold is a value lower than or equal to the reset voltage at which the wireless communication integrated circuit of second lighting control circuit 42 is reset, it is possible to reliably reset the wireless communication integrated circuit.
- the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state of the wireless communication integrated circuit, and thus the wireless communication integrated circuit is reliably reset. For that reason, lighting device 10 is capable of suppressing occurrence of control failure in second lighting control circuit 42 .
- reset circuit 50 may cause second control power supply 32 to start supply of the second voltage when first delay time Td 1 passes from a time point when reset circuit 50 detects that the first voltage has increased to second threshold Vth 2 or higher.
- a time sufficiently long for the second voltage to decrease to the third threshold or lower after second control power supply 32 is caused to stop is set as the first delay time, and thus it is possible to reliably cause the second voltage to decrease to the third threshold or lower.
- the control performed by second control power supply 32 to cause a start of supply of the second voltage to be delayed can be achieved by a simplified circuit configuration. Thus, it is possible to simplify the configuration of lighting device 10 .
- second lighting control circuit 42 may include a wireless communication integrated circuit which outputs, to first lighting control circuit 41 , an instruction signal for instructing one of turning on, turning off, and dimming of light emitting element 4 , according to an input signal from outside.
- second lighting control circuit 42 includes the wireless communication integrated circuit, it is possible to suppress occurrence of control failure in the wireless communication integrated circuit as described above.
- the first delay time may be longer than or equal to a period of time required for the second voltage to decrease from an operation voltage lower limit of the wireless communication integrated circuit to a reset voltage at which the wireless communication integrated circuit is reset, when reset circuit 50 causes second control power supply 32 to stop supply of the second voltage.
- first threshold Vth 1 and second threshold Vth 2 may be higher than or equal to an operation voltage lower limit of the wireless communication integrated circuit.
- the first delay time may be longer than a period of time taken from a start of DC power supply 20 until an operation of DC power supply 20 is stabilized.
- the wireless communication integrated circuit of second lighting control circuit 42 is activated after the operations of first lighting control circuit 41 and DC power supply 20 are stabilized, it is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start of DC power supply 20 .
- second control power supply 32 may include a three-terminal regulator.
- the following descries a lighting device according to Embodiment 2.
- the lighting device according to the present embodiment is different from lighting device 10 according to Embodiment 1, in that a second voltage output from second control power supply 32 is monitored, and control is performed based on a value of the second voltage.
- the following describes the lighting device according to the present embodiment, focusing on the difference from lighting device 10 according to Embodiment 1.
- a configuration of the lighting device according to the present embodiment shall be described with reference to FIG. 6 .
- FIG. 6 is a block diagram which illustrates a functional configuration of lighting device 110 according to the present embodiment.
- lighting device 110 includes DC power supply 20 , control power supply 130 , first lighting control circuit 41 , and second lighting control circuit 42 , as with lighting device 10 according to Embodiment 1.
- Lighting device 110 is different from lighting device 10 according to Embodiment 1, in the configuration of reset circuit 150 of control power supply 130 .
- Reset circuit 150 causes second control power supply 32 to stop supply of the second voltage when reset circuit 150 detects that the first voltage decreases from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 , as with reset circuit 50 according to Embodiment 1.
- reset circuit 150 interrupts supply of the second voltage to second lighting control circuit 42 when reset circuit 150 detects that (i) the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 , and (ii) the second voltage is higher than a third threshold and lower than a fourth threshold.
- the third threshold is the reset voltage (1.0 V) of the wireless communication integrated circuit of second lighting control circuit 42
- the fourth threshold is the lower limit value (1.8 V) of the operation voltage of the wireless communication integrated circuit of second lighting control circuit 42 .
- the third threshold and the fourth threshold only need to be substantially the same as the reset voltage and the operation voltage lower limit, respectively.
- the third threshold and the fourth threshold need not necessarily be completely identical to the reset voltage and the operation voltage lower limit, respectively.
- the third threshold and the fourth threshold may have errors of approximately 5% from the reset voltage and the operation voltage lower limit, respectively.
- reset circuit 150 includes monitoring circuit 34 and delay circuit 136 .
- Monitoring circuit 34 in the same manner as Embodiment 1, outputs a control signal for causing second control power supply 32 to stop supply of the second voltage, when monitoring circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 .
- monitoring circuit 34 outputs a control signal for causing second control power supply 32 to start supply of the second voltage, when monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 .
- Delay circuit 136 monitors the second voltage output from second control power supply 32 . When delay circuit 136 detects that the second voltage is higher than the third threshold and lower than the fourth threshold, delay circuit 136 interrupts the supply of the second voltage to second lighting control circuit 42 . In addition, when delay circuit 136 detects that the second voltage is lower than or equal to the third threshold and higher than or equal to the fourth threshold, delay circuit 136 causes second control power supply 32 to start supply of the second voltage to second lighting control circuit 42 .
- delay circuit 136 may cause the supply of the second voltage to be started after at least minimum delay time Tdmin passes from a time point when monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 . It is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start of DC power supply 20 , by setting minimum delay time Tdmin to a time longer than an unstable time taken from a start of DC power supply 20 until an operation is stabilized.
- FIG. 7 is a flowchart which illustrates an example of an operation of lighting device 110 according to the present embodiment.
- FIG. 8 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage in lighting device 110 according to the present embodiment.
- monitoring circuit 34 of reset circuit 150 in lighting device 110 monitors the first voltage, and determines whether or not a decrease from a value higher than the first threshold Vth 1 to a value lower than or equal to the first threshold Vth 1 is detected in the first voltage (S 21 ).
- monitoring circuit 34 When monitoring circuit 34 does not detect that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 (NO in S 21 ), monitoring circuit 34 repeatedly performs Step S 21 until monitoring circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 . In the example illustrated in FIG. 8 , monitoring circuit 34 performs determination as described above in a period from time point T 23 to time point T 24 , for example.
- monitoring circuit 34 when monitoring circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth 1 to a value lower than or equal to first threshold Vth 1 (YES in S 21 ), monitoring circuit 34 causes second control power supply 32 to stop supply of the second voltage (S 22 ).
- the first voltage output from first control power supply 31 starts to decrease due to, for example, a stop of power supply from AC power supply 2 at time point T 24 , and the first voltage reaches first threshold Vth 1 at time point T 25 . Accordingly, at time point T 25 , monitoring circuit 34 outputs a control signal for causing second control power supply 32 to stop the supply of the second voltage.
- Monitoring circuit 34 continues monitoring of the first voltage, and determines whether or not an increase from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 is detected in the first voltage (S 23 ).
- monitoring circuit 34 When monitoring circuit 34 does not detect that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 (NO in S 23 ), monitoring circuit 34 repeatedly performs Step S 23 until monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 . In the example illustrated in FIG. 8 , monitoring circuit 34 performs such determination as described above in a period prior to T 21 , for example.
- delay circuit 136 monitors the second voltage.
- Delay circuit 136 determines whether or not delay circuit 136 detects that the second voltage is a value higher than the third threshold (1.0 V) and lower than the fourth threshold (1.8 V) (S 24 ).
- monitoring circuit 34 outputs a control signal for causing second control power supply 32 to start an operation.
- monitoring circuit 34 outputs a control signal for causing second control power supply 32 to start an operation, at time point T 27 .
- the supply of the second voltage from second control power supply 32 is stopped by delay circuit 136 .
- delay circuit 136 When delay circuit 136 detects that the second voltage is a value higher than the third threshold and lower than the fourth threshold (YES in S 24 ), delay circuit 136 repeatedly performs Step S 24 until delay circuit 136 detects that (i) the second voltage decreases to a value lower than or equal to the third threshold, or (ii) the second voltage increases to a value higher than or equal to the fourth threshold. In the example illustrated in FIG. 8 , delay circuit 136 performs such determination as described above from immediately after time point T 27 to immediately before time point T 28 .
- monitoring circuit 34 causes supply of the second voltage to be started after at least minimum delay time Tdmin passes from a time point when monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 (S 25 ).
- delay circuit 136 causes second control power supply 32 to start supply of the second voltage after at least (i) minimum delay time Tdmin passes from a time point when monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 , and (ii) delay circuit 136 detects that the second voltage has decreased to a value lower than or equal to the third threshold or has increased to a value higher than or equal to the fourth threshold.
- delay circuit 136 detects that the second voltage has decreased to a value lower than or equal to the third threshold. Accordingly, at time point T 28 , delay circuit 136 causes second control power supply 32 to start supply of the second voltage. In this manner, it is possible to prevent the second voltage that is higher than the third threshold and lower than the fourth threshold from being supplied to second lighting control circuit 42 .
- delay circuit 136 causes second control power supply 32 to start supply of the second voltage. In this manner, it is possible to prevent the second voltage that is higher than the third threshold and lower than the fourth threshold from being supplied to second lighting control circuit 42 .
- delay circuit 136 detects that the second voltage is a value lower than or equal to the third threshold at time point T 23 when minimum delay time Tdmin passes from time point T 22 when monitoring circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 , and thus delay circuit 136 causes second control power supply 32 to start supply of the second voltage at time point T 23 . Accordingly, it is possible to start the supply of the second voltage after a delay time of a minimum necessary length.
- Step S 25 the operation returns to Step S 21 , and lighting device 110 repeats the above-described processes.
- the second voltage is not supplied to second lighting control circuit 42 when the second voltage is higher than the third threshold and lower than the fourth threshold, and thus it is possible to suppress occurrence of control failure in second lighting control circuit 42 .
- the second voltage is not higher than the third threshold or lower than the fourth threshold, it is possible to promptly (i.e., when minimum delay time Tdmin passes) supply the second voltage to second lighting control circuit 42 . For that reason, it is possible to, for example, activate lighting device 110 without involving an unnecessarily lengthy delay from the start of supply of AC power.
- reset circuit 150 causes second control power supply 32 to stop supply of the second voltage to second lighting control circuit 42 when reset circuit 150 detects that (i) the first voltage has increased from a value lower than second threshold Vth 2 to a value higher than or equal to second threshold Vth 2 , and that (ii) the second voltage is higher than a third threshold and lower than a fourth threshold.
- the third threshold may be a reset voltage of the wireless communication integrated circuit
- the fourth threshold may be an operation voltage lower limit of the wireless communication integrated circuit
- the operation of lighting device 110 according to Embodiment 2 described above is not limited to the operation indicated in FIG. 7 .
- the following describes another operation example of lighting device 110 , with reference to FIG. 9 .
- FIG. 9 is a flowchart which illustrates another example of the operation of lighting device 110 according to Embodiment 2.
- the operation example includes Step S 21 to Step S 23 , and Step S 25 which are identical to Step S 21 to Step S 23 , and Step S 25 of the operation example indicated in FIG. 7 .
- delay circuit 136 when delay circuit 136 detects that the second voltage is a value higher than the third threshold and lower than the fourth threshold in Step S 24 (YES in S 24 ), delay circuit 136 causes supply of the second voltage to be started when the second delay time Td 2 passes (S 26 ).
- second delay time Td 2 is, for example, a period of time longer than or equal to a period of time required for the second voltage to decrease from the operation voltage lower limit of the wireless communication integrated circuit to the reset voltage at which the wireless communication integrated circuit is reset, when second control power supply 32 causes supply of the second voltage to be stopped. Subsequent to Step S 26 , the operation returns to Step S 21 , and lighting device 110 repeats the processes from Step S 21 to Step S 26 .
- reset circuit 150 of lighting device 110 may cause second control power supply 32 to start supply of the second voltage to second lighting control circuit 42 when second delay time Td 2 passes from a time point when reset circuit 150 detects that the second voltage has decreased below the fourth threshold.
- lighting device 110 is capable of producing an advantageous effect same as or similar to the advantageous effect produced by the operation according to Embodiment 2.
- this eliminates the need for delay circuit 136 to continue monitoring of the second voltage, and thus it is possible to simplify the operation of delay circuit 136 .
- FIG. 10A and FIG. 10B are external views of luminaires 200 a and 200 b each including lighting device 10 or lighting device 110 .
- Luminaire 200 a illustrated in FIG. 10A is a downlight
- luminaire 200 b illustrated in FIG. 10B is a spotlight.
- Luminaire 200 a and luminaire 200 b each include circuit box 201 and lighting body 202 .
- Luminaire 200 a further includes line 203 .
- Circuit box 201 is a box in which lighting device 10 or lighting device 110 according to the above-described embodiments is housed.
- Lighting body 202 houses light emitting element 4 .
- Line 203 electrically connects circuit box 201 with a light source housed in lighting body 202 .
- Luminaire 200 a and luminaire 200 b include light emitting element 4 and lighting device 10 or lighting device 110 according to the above-described embodiments, and thus are capable of suppressing occurrence of control failure.
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Abstract
Description
- This application claims the benefit of priority of Japanese Patent Application Number 2017-026470 filed on Feb. 15, 2017, the entire content of which is hereby incorporated by reference.
- The present disclosure relates to a lighting device which supplies DC power to a light emitting element, and a luminaire.
- Luminaires which can be remotely operated by a remote control or the like are conventionally known (see, Japanese Unexamined Patent Application Publication No. 2013-70617, for example). The luminaire disclosed by Japanese Unexamined Patent Application Publication No. 2013-70617 includes a dimming signal input circuit to which a dimming signal transmitted from a remote control or the like is input. The dimming signal input circuit outputs to a switching circuit a signal corresponding to the dimming signal. The switching circuit controls a switching element at a duty ratio corresponding to the dimming signal. In this manner, it is possible to remotely operate a dimming level of the luminaire.
- In such a luminaire as disclosed by Japanese Unexamined Patent Application Publication No. 2013-70617, a control circuit such as a dimming signal input circuit is implemented by an integrated circuit such as a micro-controller unit (MCU), for example. There are instances where DC power resulting from rectifying and stepping-down AC power supplied from an AC power supply is used in operations of such an integrated circuit. In this case, power supply to the integrated circuit is interrupted by turning off a main power switch of the luminaire. When power supply to the integrated circuit is interrupted and a voltage supplied to the integrated circuit falls below an operation voltage, there could be the case where the integrated circuit is placed to an undefined state, and thus not be able to operate normally. In order to prevent a control failure due to such an undefined state, a reset function is provided to an integrated circuit. For example, when a voltage supplied to the integrated circuit becomes lower than or equal to a reset voltage that is set to a value lower than an operation voltage, the integrated circuit is reset. In this manner, when power supply to the integrated circuit is resumed, the integrated circuit is able to operate normally.
- However, for example, when a main power switch of a luminaire is repeatedly turned on and off in a short amount of time, there could be the case where a voltage supplied to an integrated circuit falls below an operation voltage, and then becomes higher than or equal to an operation voltage lower limit before becoming lower than or equal to a reset voltage. In this case, the integrated circuit is not reset and remains in the undefined state, and thus there are cases where the integrated circuit is not be able to operate normally. Such an operation failure of the integrated circuit could lead to the state where a luminaire cannot be operated by a remote control or the like.
- In view of the above, an object of the present disclosure is to provide a lighting device and a luminaire with which it is possible to suppress occurrence of operation failure in a control circuit.
- In order to achieve the above-described object, a lighting device according to an aspect of the present disclosure is a lighting device which causes a light emitting element to emit light. The lighting device includes: a DC power supply which converts AC power to DC power; a first lighting control circuit which adjusts a value of a current supplied to the light emitting element, by controlling the DC power supply; a second lighting control circuit which controls the first lighting control circuit; a first control power supply which supplies a first voltage to the first lighting control circuit; a second control power supply to which the first voltage is supplied and which supplies a second voltage to the second lighting control circuit; and a reset circuit which (i) when the reset circuit detects that the first voltage decreases to a first threshold or lower, causes the second control power supply to stop supply of the second voltage, and (ii) when the reset circuit detects that the first voltage increases to a second threshold or higher and that the second voltage is higher than a third threshold, causes the second control power supply to start supply of the second voltage after the second voltage decreases to the third threshold or lower.
- In addition, in order to achieve the above-described object, a luminaire according to an aspect of the present disclosure includes the above-described lighting device and the above-described light emitting element.
- According to the present disclosure, it is possible to provide a lighting device and a luminaire with which occurrence of operation failure in a control circuit can be suppressed.
- The figures depict one or more implementations in accordance with the present teaching, by way of examples only, not by way of limitations. In the figures, like reference numerals refer to the same or similar elements.
-
FIG. 1 is a block diagram which illustrates a functional configuration of a lighting device according toEmbodiment 1; -
FIG. 2 is a circuit diagram which illustrates another example of a circuit configuration of a control power supply according toEmbodiment 1; -
FIG. 3 is a flowchart which illustrates an operation of the lighting device according toEmbodiment 1; -
FIG. 4 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in the lighting device according toEmbodiment 1; -
FIG. 5 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in a lighting device according to a comparison example; -
FIG. 6 is a block diagram which illustrates a functional configuration of a lighting device according toEmbodiment 2; -
FIG. 7 is a flowchart which illustrates an example of an operation of the lighting device according toEmbodiment 2; -
FIG. 8 is a graph which illustrates an example of temporal waveforms of a first voltage and a second voltage in the lighting device according toEmbodiment 2; -
FIG. 9 is a flowchart which illustrates another example of an operation of the lighting device according toEmbodiment 2; -
FIG. 10A is an external view of an example of a luminaire which includes the lighting device according to each of the embodiments; and -
FIG. 10B is an external view of another example of a luminaire which includes the lighting device according to each of the embodiments. - The following describes in detail embodiments according to the present disclosure, with reference to the drawings. It should be noted that each of the embodiments described below shows a specific example of the present disclosure. The numerical values, shapes, materials, structural components, the disposition and connection of the structural components, etc. described in the following embodiments are mere examples, and do not intend to limit the present disclosure. Furthermore, among the structural components in the following embodiments, components not recited in the independent claims which indicate the broadest concepts of the present disclosure are described as arbitrary structural components.
- In addition, each diagram is a schematic diagram and not necessarily strictly illustrated. Furthermore, in the respective figures, the same numerical sign is given to identical structural components.
- The following descries a lighting device according to
Embodiment 1. - First, a configuration of the lighting device according to the present embodiment shall be described with reference to
FIG. 1 . -
FIG. 1 is a block diagram which illustrates a functional configuration oflighting device 10 according to the present embodiment. It should be noted that, inFIG. 1 ,AC power supply 2 which supplies power to lightingdevice 10,light emitting element 4 to which power is supplied fromlighting device 10, andremote control 80 which remotely operateslighting device 10 are illustrated together withlighting device 10. - AC
power supply 2 is a power supply which supplies AC power to lightingdevice 10. ACpower supply 2 is a system power supply such as a commercial AC power supply. -
Light emitting element 4 is a light source to whichlighting device 10 supplies power.Light emitting element 4 only needs to be a light source which emits light as a result of being supplied with DC power, and is not specifically limited. For example,light emitting element 4 is a solid-state light emitting element such as a light emitting diode (LED). -
Remote control 80 is a controller for remotelyoperating lighting device 10.Remote control 80, for example, performs turning on, turning off, and dimming oflight emitting element 4, by controllinglighting device 10.Remote control 80 may be a dedicated controller oflighting device 10, or may be a general mobile terminal such as a smartphone. -
Lighting device 10 is a device to which AC power is supplied, and which supplies DC power to light emittingelement 4. As illustrated inFIG. 1 ,lighting device 10 includesDC power supply 20,control power supply 30, firstlighting control circuit 41, and secondlighting control circuit 42. -
DC power supply 20 is a power supply circuit which converts AC power to DC power. According to the present embodiment,DC power supply 20 includesdiode bridge 22,boost converter 24, and step-down converter 26. It should be noted that the configuration ofDC power supply 20 is not specifically limited.DC power supply 20 only needs to be a power supply circuit which converts AC power to DC power. For example,DC power supply 20 may include a flyback converter, a buck-boost converter, etc. -
Diode bridge 22 is a circuit which rectifies AC power supplied fromAC power supply 2. -
Boost converter 24 is a circuit which boosts a voltage output fromdiode bridge 22.Boost converter 24 includes, for example, a switching element such as a metal-oxide semiconductor field-effect transistor (MOSFET), etc. The switching element included inboost converter 24 is controlled by firstlighting control circuit 41.Boost converter 24, for example, boosts a voltage of approximately 100 V output fromdiode bridge 22 to a voltage of approximately 200 V. - Step-
down converter 26 is a power supply circuit which steps down a voltage output fromboost converter 24, and supplies the stepped down voltage to light emittingelement 4. Step-down converter 26 includes, for example, a switching element such as a MOSFET. The switching element included in step-down converter 26 is controlled by firstlighting control circuit 41. Step-down converter 26, for example, steps down a voltage of approximately 200 V output fromboost converter 24, to a voltage suitable for light emittingelement 4. - First
lighting control circuit 41 is a circuit which adjusts a value of a current to be supplied to light emittingelement 4, by controllingDC power supply 20. Firstlighting control circuit 41 controlsDC power supply 20, by outputting, for example, corresponding pulse width modulation (PWM) signals to a switching element of each ofboost converter 24 and step-down converter 26 ofDC power supply 20. Power for causing firstlighting control circuit 41 to operate is supplied fromcontrol power supply 30. Firstlighting control circuit 41 is implemented by a micro-controller unit, for example. A microcomputer is a single-chip semiconductor integrated circuit which includes a ROM in which a program is stored, a RAM, a processor (central processing unit (CPU)) which executes a program, a timer, an input and output circuit including an A/D converter and a D/A converter, etc. - Second
lighting control circuit 42 is a circuit which controls firstlighting control circuit 41. According to the present embodiment, secondlighting control circuit 42 includes a wireless communication integrated circuit which outputs, to firstlighting control circuit 41, an instruction signal for instructing turning on, turning off, or dimming of light emittingelement 4, according to an input signal from outside. The wireless communication integrated circuit is implemented by a micro-controller unit, as with firstlighting control circuit 41. - Second
lighting control circuit 42, for example, receives an input signal from a controller such asremote control 80. Power for causing secondlighting control circuit 42 to operate is supplied fromcontrol power supply 30. The wireless communication integrated circuit included by secondlighting control circuit 42 has, for example, an operation voltage lower limit of 1.8 V. The wireless communication integrated circuit is reset when a voltage lower than or equal to a reset voltage of 1.0 V is supplied. Accordingly, the wireless communication integrated circuit operates normally when a voltage of higher than or equal to 1.8 V is supplied. The wireless communication integrated circuit is reset when a voltage lower than or equal to 1.0 V is supplied, and is capable of operating normally at the time of reactivation (i.e., at the time when a voltage higher than or equal to the operation voltage lower limit is supplied next time). Meanwhile, the wireless communication integrated circuit is placed to an undefined state when a voltage higher than the reset voltage (1.0 V) and lower than the operation voltage lower limit (1.8 V) is supplied. In other words, the wireless communication integrated circuit is placed in a state in which a normal operation is not secured. It should be noted that the wireless communication integrated circuit does not have a function of being reset forcibly from outside. -
Control power supply 30 is a power supply circuit which generates a first voltage and a second voltage for causing firstlighting control circuit 41 and secondlighting control circuit 42, respectively, to operate.Control power supply 30 includes firstcontrol power supply 31, secondcontrol power supply 32, and resetcircuit 50. - First control
power supply 31 is a power supply circuit which supplies a first voltage to firstlighting control circuit 41. First controlpower supply 31 only needs to be a circuit which outputs the first voltage, and the configuration of firstcontrol power supply 31 is not specifically limited. For example, first control power supply is a step-down converter to which an output voltage fromboost converter 24 is input, and which steps down the output voltage. According to the present embodiment, firstcontrol power supply 31 steps down the output voltage of approximately 200 V fromboost converter 24 to be a first voltage of 5V. First controlpower supply 31 supplies the first voltage to secondcontrol power supply 32. - Second
control power supply 32 is a power supply circuit to which the first voltage is supplied by firstcontrol power supply 31, and which supplies a second voltage to secondlighting control circuit 42. Secondcontrol power supply 32 only needs to be a circuit to which the first voltage is supplied, and which outputs the second voltage, and the configuration of secondcontrol power supply 32 is not specifically limited. For example, secondcontrol power supply 32 is a three-terminal regulator. According to the present embodiment, secondcontrol power supply 32 steps down the first voltage of 5 V to a second voltage of 3V. In addition, starting and stopping of an operation of secondcontrol power supply 32, and a delay time for starting supply of a second voltage by secondcontrol power supply 32 are controlled byreset circuit 50. -
Reset circuit 50 is a circuit which monitors the first voltage and controls an operation of secondcontrol power supply 32 according to the first voltage, thereby suppressing occurrence of operation failure in secondlighting control circuit 42. More specifically, resetcircuit 50 causes secondcontrol power supply 32 to stop supply of the second voltage, when resetcircuit 50 detects that the first voltage decreases from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1. In addition, when (i) resetcircuit 50 detects that the first voltage increases from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2, and (ii) the second voltage is higher than the third threshold, resetcircuit 50 causes secondcontrol power supply 32 to start supply of the second voltage after the second voltage decreases to the third threshold or lower. - Here, first threshold Vth1 and second threshold Vth2 are each a value higher than or equal to the operation voltage lower limit of the wireless communication integrated circuit included in second
lighting control circuit 42. According to the present embodiment, first threshold Vth1 and second threshold Vth2 are each 2.4 V, for example. In this manner, as a result of a value of the first voltage falling below the operation voltage lower limit of the wireless communication integrated circuit, it is possible to stop an operation of secondcontrol power supply 32 when the second voltage of secondcontrol power supply 32 falls below the operation voltage lower limit. For that reason, it is possible to cause secondcontrol power supply 32 to operate only when the second voltage can be higher than or equal to the operation voltage lower limit. It should be noted that, although first threshold Vth1 and second threshold Vth2 are the same value according to the present embodiment, first threshold Vth1 and second threshold Vth2 may be values different from each other. For example, first threshold Vth1 may be set to 2.3 V and second threshold Vth2 may be set to 2.5 V, and control inreset circuit 50 may implement hysteresis. - In addition, the third threshold is a value lower than or equal to a reset voltage (1.0 V) of the wireless communication integrated circuit of second
lighting control circuit 42. According to the present embodiment, the reset voltage is the third threshold. Details of the operations performed byreset circuit 50 will be given later.Reset circuit 50 includesmonitoring circuit 34 anddelay circuit 36. - Monitoring
circuit 34 is a circuit which monitors the first voltage, and controls secondcontrol power supply 32 according to the first voltage. Monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to stop supply of the second voltage, when monitoringcircuit 34 detects that the first voltage decreases from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1. In addition, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to start supply of the second voltage, when monitoringcircuit 34 detects that the first voltage increases from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2. -
Delay circuit 36 is a circuit which delays the start of supply of the second voltage by secondcontrol power supply 32. According to the present embodiment,delay circuit 36 delays the start of supply of the second voltage from when a control signal for causing secondcontrol power supply 32 to start supply of the second voltage is input by monitoringcircuit 34 to when first delay time Td1 passes. It should be noted that, in order to delay the start of supply of the second voltage from secondcontrol power supply 32,delay circuit 36 may cause the supply of the second voltage to be started when first delay time Td1 passes after the control signal is received by secondcontrol power supply 32, or may cause an output of the control signal from monitoringcircuit 34 to secondcontrol power supply 32 to be delayed. First delay time Td1 is, for example, longer than or equal to approximately 50 msec and shorter than or equal to approximately 300 msec. More preferably, first delay time Td1 is longer than or equal to approximately 80 msec and shorter than or equal to approximately 200 msec. Details of first delay time Td1 will be given later. - Monitoring
circuit 34 anddelay circuit 36 included inreset circuit 50 can be implemented by combining, for example, elements such as a comparator, a transistor, a capacitor, etc. It should be noted that the first voltage monitored by monitoringcircuit 34 may be supplied to resetcircuit 50 for causingreset circuit 50 to operate. In addition, the circuit configuration ofreset circuit 50 is not limited to the circuit configuration illustrated inFIG. 1 . For example, one ofmonitoring circuit 34 anddelay circuit 36 included inreset circuit 50 may be implemented by a single integrated circuit. An example of such a circuit configuration will be described with reference toFIG. 2 . -
FIG. 2 is a circuit diagram which illustrates another example of the circuit configuration ofcontrol power supply 30 according to the present embodiment. It should be noted that, inFIG. 2 , secondlighting control circuit 42 is also illustrated together withcontrol power supply 30. As illustrated inFIG. 2 , controlpower supply 30 includes resetcircuit 50, firstcontrol power supply 31, and secondcontrol power supply 32 which are implemented by a single integrated circuit.Control power supply 30 further includescapacitors Capacitors control power supply 31 and the second voltage output from secondcontrol power supply 32, respectively.Capacitor 52 is an element for adjusting first delay time Td1. - As illustrated in
FIG. 2 , the first voltage output from output terminal OUT of firstcontrol power supply 31 is input to each of input terminals IN ofreset circuit 50 and secondcontrol power supply 32. It should be noted that, although not illustrated inFIG. 2 , the first voltage is also input to firstlighting control circuit 41.Reset circuit 50 outputs a control signal for controlling a start and a stop of the supply of the second voltage, from output terminal OUT to control terminal TC of secondcontrol power supply 32. In the example illustrated inFIG. 2 , a control signal for instructing a start of supply of the second voltage is output from output terminal OUT ofreset circuit 50, when first delay time Td1 passes from a time point whenreset circuit 50 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2. In this manner, it is possible to produce an advantageous effect same as or similar to the advantageous effect produced bylighting device 10 illustrated inFIG. 1 . In addition, it is possible to implementreset circuit 50 by a single integrated circuit according to the circuit configuration illustrated inFIG. 2 . Accordingly, the size ofcontrol power supply 30 can be reduced. - Next, an operation of
lighting device 10 according to the present embodiment will be described with reference toFIG. 3 andFIG. 4 . -
FIG. 3 is a flowchart which illustrates an operation oflighting device 10 according to the present embodiment.FIG. 4 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage inlighting device 10 according to the present embodiment. - The following describes the flow of an operation performed by
lighting device 10 illustrated inFIG. 3 , with reference toFIG. 4 . - First, an operation of
lighting device 10 is started as illustrated inFIG. 3 (at time point T1 and at time point T6 inFIG. 4 ). Along with the start of the operation oflighting device 10, the first voltage output from firstcontrol power supply 31 increases (from time point T1 to time point T2, and from time point T6 to time point T7 inFIG. 4 ). - Monitoring
circuit 34 ofreset circuit 50 inlighting device 10 monitors the first voltage, and determines whether or not an increase from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 is detected in the first voltage (S11). - When monitoring
circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 (YES in S11),monitoring circuit 34 causes secondcontrol power supply 32 to start supply of the second voltage when first delay time Td1 passes from a time point of the detection (S12). In the example illustrated inFIG. 4 , power supply fromAC power supply 2 is started and the first voltage output from firstcontrol power supply 31 starts to increase at time point T1 and time point T6, and the first voltage reaches second threshold Vth2 (Vth2=Vth1, according to the present embodiment) at time point T2 and time point T7. Accordingly, at time point T2 and time point T7, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to start supply of the second voltage. Secondcontrol power supply 32 starts supply of the second voltage at time point T3 and time point T8 when first delay time Td1 determined bydelay circuit 36 passes from time point T2 and time point T7 when the control signal is received. As indicated by time point T7 to time point T8 inFIG. 4 , first delay time Td1 is a period of time longer than or equal to a period of time required for the second voltage to decrease from the operation voltage lower limit (1.8 V) of the wireless communication integrated circuit of secondlighting control circuit 42 to a reset voltage (1.0 V) when secondcontrol power supply 32 causes the supply of the second voltage to be stopped. For that reason, when secondcontrol power supply 32 receives an instruction for resuming the supply of the second voltage, the second voltage is lower than or equal to the reset voltage of the wireless communication integrated circuit. In other words, the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state that is (i) lower than the operation voltage lower limit of the wireless communication integrated circuit and (ii) higher than the reset voltage, thereby reliably resetting the wireless communication integrated circuit at time point T8. Accordingly, it is possible to suppress occurrence of control failure in the wireless communication integrated circuit. - Subsequent to Step S12, the operation proceeds to Step S13. In the case where, in Step S11, monitoring
circuit 34 does not detect an increase from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 in the first voltage (NO in S11), the operation returns to Step S11. In the example illustrated inFIG. 4 , monitoringcircuit 34 performs determination as described above in a period from time point T1 to immediately before time point T2, and a period from time point T6 to immediately before time point T7. - Next, monitoring
circuit 34 continues monitoring of the first voltage, and determines whether or not a decrease from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1 is detected in the first voltage (S13). - When monitoring
circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1 (YES in S13),monitoring circuit 34 causes secondcontrol power supply 32 to stop the supply of the second voltage (S14). For example, in the example illustrated inFIG. 4 , the first voltage output from firstcontrol power supply 31 starts to decrease due to, for example, a stop of power supply fromAC power supply 2 at time point T4, and the first voltage reaches first threshold Vth1 at time point T5. Accordingly, at time point T5, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to stop the supply of the second voltage. Subsequent to Step S14, the operation returns to Step S11. - On the other hand, when monitoring
circuit 34 does not detect that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1 (NO in S13),monitoring circuit 34 does not cause secondcontrol power supply 32 to stop the supply of the second voltage, and the operation returns to Step S13. In the example illustrated inFIG. 4 , monitoringcircuit 34 performs determination as described above in a period from time point T3 to time point T4, for example. -
Lighting device 10 repeats the above-described processes from Step S11 to Step S14. - As described above,
lighting device 10 is capable of suppressing occurrence of control failure in the wireless communication integrated circuit of secondlighting control circuit 42. Here, in order to explain an advantageous effect oflighting device 10, an operation example of a lighting device according to a comparison example will be described with reference toFIG. 5 . -
FIG. 5 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage in a lighting device according to the comparison example. The lighting device according to the comparison example has a configuration same as the configuration oflighting device 10 according to the present embodiment, other than that the lighting device according to the comparison example does not includereset circuit 50. - As illustrated in
FIG. 5 , when supply of AC power to the lighting device according to the comparison example is started at time point T11, the first voltage starts to increase, and the second voltage also starts to increase along with the increase of the first voltage. When the supply of AC power is stopped at time point T12, the first voltage starts to decrease, and the second voltage also starts to decrease along with the decrease of the first voltage. When supply of AC power is started at time point T13 immediately after time point T12, the first voltage starts to increase, and the second voltage also starts to increase at time point T14 immediately after time point T13 and exceeds the operation voltage lower limit of the wireless communication integrated circuit. At the above-described time point T14, there could be the case where the second voltage is lower than the operation voltage lower limit (1.8 V) of the wireless communication integrated circuit and higher than the reset voltage (1.0 V), as illustrated inFIG. 5 . In this case, the wireless communication integrated circuit is supplied with the second voltage higher than or equal to the operation voltage lower limit, without being reset from the undefined state. Accordingly, control failure could occur in the wireless communication integrated circuit. - In contrast, with
lighting device 10 according to the present embodiment, the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state as described above. As a result, the wireless communication integrated circuit is reliably reset. For that reason, withlighting device 10, it is possible to suppress occurrence of control failure more reliably than the lighting device according to the comparison example. - In addition, in
lighting device 10, first delay time Td1 may be longer than an unstable time taken from a start ofDC power supply 20 until an operation is stabilized. Here, that the operation ofDC power supply 20 is stabilized indicates, for example, the state in which a variation width of an output voltage ofDC power supply 20 is less than or equal to 5%. With this, since the wireless communication integrated circuit of secondlighting control circuit 42 is activated after the operations of firstlighting control circuit 41 andDC power supply 20 are stabilized, it is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start ofDC power supply 20. It should be noted that the unstable time is approximately 100 msec, for example. - As described above,
lighting device 10 according to the present embodiment is a device which causes light emittingelement 4 to emit light.Lighting device 10 includes:DC power supply 20 which converts AC power to DC power; firstlighting control circuit 41 which adjusts a value of a current supplied to light emittingelement 4 by controllingDC power supply 20; and secondlighting control circuit 42 which controls firstlighting control circuit 41.Lighting device 10 further includes: firstcontrol power supply 31 which supplies a first voltage to firstlighting control circuit 41; secondcontrol power supply 32 to which the first voltage is supplied and which supplies a second voltage to secondlighting control circuit 42; and resetcircuit 50.Reset circuit 50, when resetcircuit 50 detects that the first voltage decreases to a first threshold or lower, causes secondcontrol power supply 32 to stop supply of the second voltage. In addition, resetcircuit 50, when resetcircuit 50 detects that the first voltage increases to a second threshold or higher and that the second voltage is higher than a third threshold, causes secondcontrol power supply 32 to start supply of the second voltage after the second voltage decreases to the third threshold or lower. - In this manner, it is possible to resume supply of the second voltage after the second voltage decreases to the third threshold or lower, by causing second
control power supply 32 to stop the supply of the second voltage. Here, when the third threshold is a value lower than or equal to the reset voltage at which the wireless communication integrated circuit of secondlighting control circuit 42 is reset, it is possible to reliably reset the wireless communication integrated circuit. In other words, the second voltage decreases to the reset voltage or lower after the second voltage falls into a range of the undefined state of the wireless communication integrated circuit, and thus the wireless communication integrated circuit is reliably reset. For that reason,lighting device 10 is capable of suppressing occurrence of control failure in secondlighting control circuit 42. - In addition, in
lighting device 10, resetcircuit 50 may cause secondcontrol power supply 32 to start supply of the second voltage when first delay time Td1 passes from a time point whenreset circuit 50 detects that the first voltage has increased to second threshold Vth2 or higher. - In this manner, a time sufficiently long for the second voltage to decrease to the third threshold or lower after second
control power supply 32 is caused to stop is set as the first delay time, and thus it is possible to reliably cause the second voltage to decrease to the third threshold or lower. In addition, the control performed by secondcontrol power supply 32 to cause a start of supply of the second voltage to be delayed can be achieved by a simplified circuit configuration. Thus, it is possible to simplify the configuration oflighting device 10. - In addition, in
lighting device 10, secondlighting control circuit 42 may include a wireless communication integrated circuit which outputs, to firstlighting control circuit 41, an instruction signal for instructing one of turning on, turning off, and dimming of light emittingelement 4, according to an input signal from outside. - In this manner, when second
lighting control circuit 42 includes the wireless communication integrated circuit, it is possible to suppress occurrence of control failure in the wireless communication integrated circuit as described above. - In addition, in
lighting device 10, the first delay time may be longer than or equal to a period of time required for the second voltage to decrease from an operation voltage lower limit of the wireless communication integrated circuit to a reset voltage at which the wireless communication integrated circuit is reset, when resetcircuit 50 causes secondcontrol power supply 32 to stop supply of the second voltage. - In this manner, when the supply of the second voltage is resumed by second
control power supply 32, the wireless communication integrated circuit is reliably reset. For that reason, it is possible to more reliably suppress occurrence of control failure in the wireless communication integrated circuit. - In addition, in
lighting device 10, at least one of first threshold Vth1 and second threshold Vth2 may be higher than or equal to an operation voltage lower limit of the wireless communication integrated circuit. - In this manner, as a result of the first voltage falling below the operation voltage lower limit of the wireless communication integrated circuit, it is possible to stop supply of the second voltage from second
control power supply 32 before the second voltage of secondcontrol power supply 32 falls below the operation voltage lower limit. For that reason, it is possible to cause secondcontrol power supply 32 to operate only when the second voltage can be higher than or equal to the operation voltage lower limit. - In addition, in
lighting device 10, the first delay time may be longer than a period of time taken from a start ofDC power supply 20 until an operation ofDC power supply 20 is stabilized. - With this, since the wireless communication integrated circuit of second
lighting control circuit 42 is activated after the operations of firstlighting control circuit 41 andDC power supply 20 are stabilized, it is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start ofDC power supply 20. - In addition, in
lighting device 10, secondcontrol power supply 32 may include a three-terminal regulator. - According to this configuration, it is possible to simplify the configuration of second
control power supply 32. - The following descries a lighting device according to
Embodiment 2. The lighting device according to the present embodiment is different fromlighting device 10 according toEmbodiment 1, in that a second voltage output from secondcontrol power supply 32 is monitored, and control is performed based on a value of the second voltage. The following describes the lighting device according to the present embodiment, focusing on the difference fromlighting device 10 according toEmbodiment 1. - A configuration of the lighting device according to the present embodiment shall be described with reference to
FIG. 6 . -
FIG. 6 is a block diagram which illustrates a functional configuration oflighting device 110 according to the present embodiment. As illustrated inFIG. 6 ,lighting device 110 includesDC power supply 20,control power supply 130, firstlighting control circuit 41, and secondlighting control circuit 42, as withlighting device 10 according toEmbodiment 1.Lighting device 110 is different fromlighting device 10 according toEmbodiment 1, in the configuration ofreset circuit 150 ofcontrol power supply 130. -
Reset circuit 150 causes secondcontrol power supply 32 to stop supply of the second voltage whenreset circuit 150 detects that the first voltage decreases from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1, as withreset circuit 50 according toEmbodiment 1. In addition,reset circuit 150 interrupts supply of the second voltage to secondlighting control circuit 42 whenreset circuit 150 detects that (i) the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2, and (ii) the second voltage is higher than a third threshold and lower than a fourth threshold. Here, the third threshold is the reset voltage (1.0 V) of the wireless communication integrated circuit of secondlighting control circuit 42, and the fourth threshold is the lower limit value (1.8 V) of the operation voltage of the wireless communication integrated circuit of secondlighting control circuit 42. It should be noted that the third threshold and the fourth threshold only need to be substantially the same as the reset voltage and the operation voltage lower limit, respectively. The third threshold and the fourth threshold need not necessarily be completely identical to the reset voltage and the operation voltage lower limit, respectively. For example, the third threshold and the fourth threshold may have errors of approximately 5% from the reset voltage and the operation voltage lower limit, respectively. - As illustrated in
FIG. 6 , resetcircuit 150 includesmonitoring circuit 34 anddelay circuit 136. - Monitoring
circuit 34, in the same manner asEmbodiment 1, outputs a control signal for causing secondcontrol power supply 32 to stop supply of the second voltage, when monitoringcircuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1. In addition, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to start supply of the second voltage, when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2. -
Delay circuit 136 monitors the second voltage output from secondcontrol power supply 32. Whendelay circuit 136 detects that the second voltage is higher than the third threshold and lower than the fourth threshold,delay circuit 136 interrupts the supply of the second voltage to secondlighting control circuit 42. In addition, whendelay circuit 136 detects that the second voltage is lower than or equal to the third threshold and higher than or equal to the fourth threshold,delay circuit 136 causes secondcontrol power supply 32 to start supply of the second voltage to secondlighting control circuit 42. According to the present embodiment,delay circuit 136 may cause the supply of the second voltage to be started after at least minimum delay time Tdmin passes from a time point when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2. It is possible to prevent a communication of the wireless communication integrated circuit from being affected by a noise due to an inrush current at the time of a start ofDC power supply 20, by setting minimum delay time Tdmin to a time longer than an unstable time taken from a start ofDC power supply 20 until an operation is stabilized. - Next, an operation of
lighting device 110 according to the present embodiment will be described with reference toFIG. 7 andFIG. 8 . -
FIG. 7 is a flowchart which illustrates an example of an operation oflighting device 110 according to the present embodiment.FIG. 8 is a graph which illustrates an example of temporal waveforms of the first voltage and the second voltage inlighting device 110 according to the present embodiment. - The following describes the flow of an operation performed by
lighting device 110 illustrated inFIG. 7 , with reference toFIG. 8 . - As illustrated in
FIG. 7 , first, monitoringcircuit 34 ofreset circuit 150 inlighting device 110 monitors the first voltage, and determines whether or not a decrease from a value higher than the first threshold Vth1 to a value lower than or equal to the first threshold Vth1 is detected in the first voltage (S21). - When monitoring
circuit 34 does not detect that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1 (NO in S21),monitoring circuit 34 repeatedly performs Step S21 until monitoringcircuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1. In the example illustrated inFIG. 8 , monitoringcircuit 34 performs determination as described above in a period from time point T23 to time point T24, for example. - On the other hand, when monitoring
circuit 34 detects that the first voltage has decreased from a value higher than first threshold Vth1 to a value lower than or equal to first threshold Vth1 (YES in S21),monitoring circuit 34 causes secondcontrol power supply 32 to stop supply of the second voltage (S22). For example, in the example illustrated inFIG. 8 , the first voltage output from firstcontrol power supply 31 starts to decrease due to, for example, a stop of power supply fromAC power supply 2 at time point T24, and the first voltage reaches first threshold Vth1 at time point T25. Accordingly, at time point T25, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to stop the supply of the second voltage. - Monitoring
circuit 34 continues monitoring of the first voltage, and determines whether or not an increase from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 is detected in the first voltage (S23). - When monitoring
circuit 34 does not detect that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 (NO in S23),monitoring circuit 34 repeatedly performs Step S23 until monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2. In the example illustrated inFIG. 8 , monitoringcircuit 34 performs such determination as described above in a period prior to T21, for example. - On the other hand, when monitoring
circuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 (YES in S23),delay circuit 136 monitors the second voltage.Delay circuit 136 determines whether or not delaycircuit 136 detects that the second voltage is a value higher than the third threshold (1.0 V) and lower than the fourth threshold (1.8 V) (S24). According to the present embodiment, when an increase in the first voltage from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 is detected, monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to start an operation. In the example illustrated inFIG. 8 , monitoringcircuit 34 outputs a control signal for causing secondcontrol power supply 32 to start an operation, at time point T27. However, at time point T27, the supply of the second voltage from secondcontrol power supply 32 is stopped bydelay circuit 136. - When
delay circuit 136 detects that the second voltage is a value higher than the third threshold and lower than the fourth threshold (YES in S24),delay circuit 136 repeatedly performs Step S24 untildelay circuit 136 detects that (i) the second voltage decreases to a value lower than or equal to the third threshold, or (ii) the second voltage increases to a value higher than or equal to the fourth threshold. In the example illustrated inFIG. 8 ,delay circuit 136 performs such determination as described above from immediately after time point T27 to immediately before time point T28. - On the other hand, when
delay circuit 136 does not detect that the second voltage is a value higher than the third threshold and lower than the fourth threshold (NO in S24),monitoring circuit 34 causes supply of the second voltage to be started after at least minimum delay time Tdmin passes from a time point when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2 (S25). More specifically,delay circuit 136 causes secondcontrol power supply 32 to start supply of the second voltage after at least (i) minimum delay time Tdmin passes from a time point when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2, and (ii)delay circuit 136 detects that the second voltage has decreased to a value lower than or equal to the third threshold or has increased to a value higher than or equal to the fourth threshold. - In the example illustrated in
FIG. 8 , at time point T28 when delay time Td that is longer than minimum delay time Tdmin passes from time point T27 when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2,delay circuit 136 detects that the second voltage has decreased to a value lower than or equal to the third threshold. Accordingly, at time point T28,delay circuit 136 causes secondcontrol power supply 32 to start supply of the second voltage. In this manner, it is possible to prevent the second voltage that is higher than the third threshold and lower than the fourth threshold from being supplied to secondlighting control circuit 42. In addition, InFIG. 8 ,delay circuit 136 detects that the second voltage is a value lower than or equal to the third threshold at time point T23 when minimum delay time Tdmin passes from time point T22 when monitoringcircuit 34 detects that the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2, and thus delaycircuit 136 causes secondcontrol power supply 32 to start supply of the second voltage at time point T23. Accordingly, it is possible to start the supply of the second voltage after a delay time of a minimum necessary length. - Subsequent to Step S25, the operation returns to Step S21, and
lighting device 110 repeats the above-described processes. - As described above, with
lighting device 110 according to the present embodiment, the second voltage is not supplied to secondlighting control circuit 42 when the second voltage is higher than the third threshold and lower than the fourth threshold, and thus it is possible to suppress occurrence of control failure in secondlighting control circuit 42. In addition, when the second voltage is not higher than the third threshold or lower than the fourth threshold, it is possible to promptly (i.e., when minimum delay time Tdmin passes) supply the second voltage to secondlighting control circuit 42. For that reason, it is possible to, for example, activatelighting device 110 without involving an unnecessarily lengthy delay from the start of supply of AC power. - As described above, in
lighting device 110 according to the present embodiment, resetcircuit 150 causes secondcontrol power supply 32 to stop supply of the second voltage to secondlighting control circuit 42 whenreset circuit 150 detects that (i) the first voltage has increased from a value lower than second threshold Vth2 to a value higher than or equal to second threshold Vth2, and that (ii) the second voltage is higher than a third threshold and lower than a fourth threshold. - In this manner, it is possible to suppress occurrence of control failure in second
lighting control circuit 42, as withEmbodiment 1. In addition, since the second voltage is monitored and supply of the second voltage is started when the second voltage is not higher than the third threshold or lower than the fourth threshold, it is possible to prevent activation oflighting device 110 from being delayed more than necessary. - In addition, in
lighting device 110, the third threshold may be a reset voltage of the wireless communication integrated circuit, and the fourth threshold may be an operation voltage lower limit of the wireless communication integrated circuit. - This prevents second
lighting control circuit 42 from being supplied with the second voltage which causes the wireless communication integrated circuit to be placed in an undefined state, and thus it is possible to suppress occurrence of control failure inlighting device 110. - Although the lighting device according to the present disclosure is described based on each of the embodiments, the present disclosure is not limited to the above-described embodiments. Other forms in which various modifications apparent to those skilled in the art are applied to the above-described embodiments or forms in which some structural components according to the embodiment and variation examples are arbitrarily combined within the scope of the present discloser are also included within the scope of the present disclosure unless such changes and modifications depart from the scope of the present disclosure.
- For example, the operation of
lighting device 110 according toEmbodiment 2 described above is not limited to the operation indicated inFIG. 7 . The following describes another operation example oflighting device 110, with reference toFIG. 9 . -
FIG. 9 is a flowchart which illustrates another example of the operation oflighting device 110 according toEmbodiment 2. - As illustrated in
FIG. 9 , the operation example includes Step S21 to Step S23, and Step S25 which are identical to Step S21 to Step S23, and Step S25 of the operation example indicated inFIG. 7 . However, in the operation example illustrated inFIG. 9 , whendelay circuit 136 detects that the second voltage is a value higher than the third threshold and lower than the fourth threshold in Step S24 (YES in S24),delay circuit 136 causes supply of the second voltage to be started when the second delay time Td2 passes (S26). Here, second delay time Td2 is, for example, a period of time longer than or equal to a period of time required for the second voltage to decrease from the operation voltage lower limit of the wireless communication integrated circuit to the reset voltage at which the wireless communication integrated circuit is reset, when secondcontrol power supply 32 causes supply of the second voltage to be stopped. Subsequent to Step S26, the operation returns to Step S21, andlighting device 110 repeats the processes from Step S21 to Step S26. - As described above, reset
circuit 150 oflighting device 110 may cause secondcontrol power supply 32 to start supply of the second voltage to secondlighting control circuit 42 when second delay time Td2 passes from a time point whenreset circuit 150 detects that the second voltage has decreased below the fourth threshold. - In this manner,
lighting device 110 is capable of producing an advantageous effect same as or similar to the advantageous effect produced by the operation according toEmbodiment 2. In addition, this eliminates the need fordelay circuit 136 to continue monitoring of the second voltage, and thus it is possible to simplify the operation ofdelay circuit 136. - In addition, it is possible to apply
lighting device 10 andlighting device 110 according to the above-described embodiments to various luminaires. -
FIG. 10A andFIG. 10B are external views ofluminaires lighting device 10 orlighting device 110.Luminaire 200 a illustrated inFIG. 10A is a downlight, andluminaire 200 b illustrated inFIG. 10B is a spotlight.Luminaire 200 a andluminaire 200 b each includecircuit box 201 andlighting body 202.Luminaire 200 a further includesline 203.Circuit box 201 is a box in whichlighting device 10 orlighting device 110 according to the above-described embodiments is housed.Lighting body 202 houses light emittingelement 4.Line 203 electrically connectscircuit box 201 with a light source housed inlighting body 202. -
Luminaire 200 a andluminaire 200 b includelight emitting element 4 andlighting device 10 orlighting device 110 according to the above-described embodiments, and thus are capable of suppressing occurrence of control failure. - While the foregoing has described one or more embodiments and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present teachings.
Claims (20)
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