JP2021136705A - Lighting device and luminaire - Google Patents

Abstract

To provide a lighting device and a luminaire enabling light sources to be lighted according to a plurality of input voltage values.SOLUTION: A lighting device 10 in a luminaire 100 comprises: a lighting circuit 60 supplied with an input voltage from a DC power source DC to thereby cause a light source to be lighted; and a control unit 30 that switches the operation of the lighting circuit between the step-up operation and the step-down operation according to the input voltage. The lighting circuit is stepped up when the input voltage is a first voltage, and the lighting circuit is stepped down when the input voltage is a second voltage higher than the first voltage.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to lighting devices and luminaires.

Patent Document 1 discloses a power supply unit. This power supply unit has a smoothing capacitor that smoothes the output from the DC power supply and a power supply circuit that supplies power to the light source. The power supply circuit includes a switching element connected to the positive electrode side of the smoothing capacitor and a control terminal circuit for switching the switching element.

Japanese Unexamined Patent Publication No. 2013-70583

In Patent Document 1, LED lighting is turned on by using a DC power supply. Various voltage values may be used as the input voltage from the DC power supply. It is inefficient to prepare a dedicated luminaire for each input voltage value.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to obtain a lighting device and a lighting fixture capable of lighting a light source corresponding to a plurality of input voltage values.

The lighting device according to the present disclosure is a lighting circuit that lights a light source by supplying an input voltage from a DC power supply, and a control unit that switches the operation of the lighting circuit between a step-up operation and a step-down operation according to the input voltage. And.

In the lighting device and the luminaire according to the present disclosure, the operation of the lighting circuit is switched between the step-up operation and the step-down operation. As a result, the light source can be turned on in response to a plurality of input voltage values.

It is a circuit block diagram of the lighting device and the lighting equipment which concerns on Embodiment 1. FIG. It is a figure explaining the current path of the step-up chopper circuit. It is a figure explaining the current path of a back converter circuit.

The lighting device and the luminaire according to the embodiment will be described with reference to the drawings. The same or corresponding components may be designated by the same reference numerals and the description may be omitted. In addition, when referring to the connection below, it is assumed that an electrical connection is included.

Embodiment 1.
FIG. 1 is a circuit block diagram of the lighting fixture 100 according to the first embodiment. The luminaire 100 includes a lighting device 10 and a light source 20. The lighting device 10 is a power supply device that is supplied with electric power from the DC power supply DC to light the light source 20. The DC power supply DC is, for example, a power supply or a storage battery supplied from a photovoltaic power generation system. The input voltage from the DC power source DC and _{V in.} Further, the GND negative side potential of the DC power source as a reference of the input voltage _{V in.}

The light source 20 has a plurality of light emitting elements 21 connected in series. The light emitting element 21 is, for example, an LED. The light source 20 may have at least one light emitting element 21. The plurality of light emitting elements 21 may be connected in parallel or in series and parallel.

The lighting device 10 includes a control unit 30, a control power supply circuit 40, a step-down circuit 50, a lighting circuit 60, an input voltage detection circuit, and an electrolytic capacitor C2.

The input voltage detection circuit is formed of resistors R2 and R3 connected in series. One end of the input voltage detection circuit is connected to the positive potential side terminal of the DC power supply DC. The other end of the input voltage detection circuit is connected to the negative potential side terminal of the DC power supply DC. The connection points of the resistors R2 and R3 are connected to the Vin terminal of the control unit 30. The control unit 30 divides detecting the input voltage _{V in} a series circuit of resistors R2, R3.

Lighting circuit 60 is supplied with input voltage _{V in} from the DC power source to light the light source 20. The lighting circuit 60 has a pair of lines 61 and 62 that receive power from the DC power supply DC. Of the lines 61 and 62, the high potential side is the line 61, and the low potential side is the line 62. One end of the line 61 is connected to the positive potential side terminal of the DC power supply DC. One end of the line 62 is connected to the negative potential side terminal of the DC power supply DC.

The lighting circuit 60 has a pair of output terminals 63, 64 that supply electric power to the light source 20. Of the output ends 63 and 64, the high potential side is the output end 63, and the low potential side is the output end 64. The anode terminal of the light source 20 is connected to the output terminal 63. The cathode terminal of the light source 20 is connected to the output terminal 64.

In the lighting circuit 60, one end of the inductor L1 is electrically connected to the other end of the line 61. The cathode of the first diode D1 is electrically connected to one end of the inductor L1 and the line 61. The anode of the second diode D2 is electrically connected to the other end of the inductor L1. The cathode of the second diode D2 is electrically connected to the output terminal 63.

The first switching element Q1 has a first terminal, a second terminal, and a first control terminal for switching on / off between the first terminal and the second terminal. The first switching element Q1 is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effective Transistor). When the first switching element Q1 is a MOSFET, the first terminal is a drain, the second terminal is a source, and the first control terminal is a gate.

The first terminal of the first switching element Q1 is electrically connected to the other end of the inductor L1 and the anode of the second diode D2. The second terminal of the first switching element Q1 is electrically connected to the anode and output terminal 64 of the first diode D1. The first control terminal of the first switching element Q1 is electrically connected to the Q1DRV terminal of the control unit 30.

The second switching element Q2 has a third terminal, a fourth terminal, and a second control terminal for switching on / off between the third terminal and the fourth terminal. The second switching element Q2 is, for example, a MOSFET. When the second switching element Q2 is a MOSFET, the third terminal is a drain, the fourth terminal is a source, and the second control terminal is a gate.

The third terminal of the second switching element Q2 is electrically connected to the output terminal 64. Further, the third terminal of the second switching element Q2 is electrically connected to the connection point between the anode of the first diode D1 and the second terminal of the first switching element Q1. The fourth terminal of the second switching element Q2 is electrically connected to the other end of the line 62. The second control terminal of the second switching element Q2 is electrically connected to the Q2DRV terminal of the control unit 30.

A resistor R1 is provided on the line 62. One end of the resistor R1 is connected to the fourth terminal of the second switching element Q2. The other end of the resistor R1 is connected to the grounding terminal. One end of the resistor R1 is connected to the IFB terminal of the control unit 30.

The capacitor C1 is connected in parallel with the light source 20. The capacitor C1 is connected between the output terminals 63 and 64. The capacitor C1 smoothes the current flowing through the light source 20.

The inductor L1 has a secondary winding. One end of the secondary winding is connected to the grounding terminal. The other end of the secondary winding is connected to the ZCD terminal of the control unit 30.

Control unit 30 For example, a composite IC. The control unit 30 includes, for example, a microcomputer and a driver. The control unit 30 controls the lighting circuit 60. The control unit 30 outputs signals for switching the first switching element Q1 and the second switching element Q2 from the Q1DRV terminal and the Q2DRV terminal, respectively. The control unit 30 has a VB terminal to which a voltage V1 for driving the first switching element Q1 and the second switching element Q2 by a driver is input.

Control unit 30, the input voltage _{V in} input to the lighting device detects the Vin terminal. Further, the control unit 30 detects the voltage generated in the secondary winding of the inductor L1 by the ZCD terminal.

Further, a voltage corresponding to the light source current flowing through the light source 20 is generated in the resistor R1. The control unit 30 detects the voltage generated in the resistor R1 by the IFB terminal and detects the light source current.

The control power supply circuit 40 is a step-down circuit such as a back converter circuit. Control power supply circuit 40 steps down the voltage V1 to a predetermined input voltage V _in. An electrolytic capacitor C2 is connected between the output of the control power supply circuit 40 and the grounding terminal. The electrolytic capacitor C2 smoothes the voltage V1 generated by the control power supply circuit 40. As a result, the voltage V1 of the control power supply is generated. The voltage V1 is, for example, 13V.

The control power supply circuit 40 may be a circuit capable of stepping down. The control power supply circuit 40 may be a flyback circuit. The control power supply circuit 40 may be a regulator circuit. Here, if the input voltage V _in for example 380V, there is a possibility that the loss at the time of buck of the regulator circuit is increased. Therefore, it is desirable that the control power supply circuit 40 is a switching circuit.

The step-down circuit 50 is connected between the output of the control power supply circuit 40 and the VDD terminal of the control unit 30. The step-down circuit 50 generates a power supply voltage VDD for the control unit 30 from the voltage V1. The step-down circuit 50 is composed of, for example, a regulator circuit. The power supply voltage VDD is, for example, 3.3 V.

Next, the operation at the time of starting the lighting equipment 100 will be described. When the input voltage V _in is applied to the lighting device 10, the control power supply circuit 40 and the step-down circuit 50 operates, the voltage V1 and the power supply voltage VDD is generated. When the power supply voltage VDD rises to the operable voltage of the control unit 30, the control unit 30 is activated. The activated control unit 30 detects the input voltage _{V in.}

Control unit 30 detects that the input voltage _{V in} is DC48V, operating the lighting circuit 60 as the step-up chopper circuit. The control unit 30 detects that the input voltage _{V in} is 380 V DC, to operate the lighting circuit 60 as the buck converter circuit. The control unit 30, when the input voltage V _in is not a normal value range, the process proceeds to a protection mode. At this time, the control unit 30 does not switch the lighting circuit 60, and keeps the first switching element Q1 and the second switching element Q2 in the off state.

The detailed circuit operation will be described below. Here, as an example, it is assumed that the forward current of the light source 20 is 250 mA and the forward voltage is 100 V. The forward current and forward voltage of the light source 20 may be values that can be realized by the boost chopper circuit and the back converter circuit.

FIG. 2 is a diagram illustrating a current path of the step-up chopper circuit. When the control section 30 detects the 48V as the input voltage _{V in,} to operate the boost chopper circuit. The control unit 30 keeps the second switching element Q2 in the ON state and turns the first switching element Q1 on and off to operate the lighting circuit 60 as a step-up chopper circuit. The boost chopper circuit is composed of an inductor L1, a second diode D2, and a first switching element Q1.

When the first switching element Q1 is turned on in the steady state, a current flows along the path shown by the solid line in FIG. At this time, the inductor L1 is charged with energy. After the on period elapses, the first switching element Q1 turns off. As a result, the energy stored in the inductor L1 is discharged. At this time, a current flows through the path shown by the broken line in FIG.

During discharging, a voltage corresponding to the voltage across the inductor L1 and the turns ratio is generated in the secondary winding of the inductor L1. When this voltage falls below a predetermined threshold value, the first switching element Q1 turns on again. That is, the lighting circuit 60 operates in the critical mode.

The control unit 30 converts the light source current flowing through the light source 20 into a voltage with the resistor R1 and detects it from the IFB terminal. The control unit 30 changes the ON period of the first switching element Q1 so that the detection voltage from the IFB terminal becomes the target voltage. As a result, the target constant current flows through the light source 20.

The feedback of the light source current is performed by detecting the peak current. In the case of the step-up chopper circuit, the period during which the current flows through the light source 20 is only when the first switching element Q1 is turned off. When operating in the critical mode, the current _Iavg flowing through the light source 20 can be obtained by Eq. (1).

In turn-on period _{T on,} the energy P (on) the formula (2) to be charged to the current _{I o-p} (on) and an inductor L1 flowing to inductor L1, represented by formula (3).

In the turn-off period To _off , the current I _op (off) that the inductor L1 discharges and the energy P (off) that the inductor L1 discharges are represented by the equations (4) and (5).

Since of the critical mode, equation (6) holds.

For example, the forward voltage of the light source 20 is 100 V, the forward current is 250 mA, and the inductor L1 is 1 mH. In this case, the switching frequency is _{24kHz, T on} the _{21.7μs, T off} the _{20.0μs, I o-p} will be 1.04A.

FIG. 3 is a diagram illustrating a current path of the back converter circuit. The control unit 30 detects an 380V as the input voltage _{V in,} to operate the buck converter circuit. The control unit 30 keeps the first switching element Q1 in the off state and turns the second switching element Q2 on and off to operate the lighting circuit 60 as a back converter circuit. The back converter circuit is composed of an inductor L1, a first diode D1, and a second switching element Q2.

When the second switching element Q2 is turned on during steady state, a current flows along the path shown by the solid line in FIG. As a result, the inductor L1 is charged with energy. After the on period elapses, the second switching element Q2 turns off. As a result, the energy stored in the inductor L1 is discharged. At this time, a current flows along the path shown by the broken line in FIG.

During discharging, a voltage corresponding to the voltage across the inductor L1 and the turns ratio is generated in the secondary winding of the inductor L1. When this voltage falls below a predetermined threshold, the second switching element Q2 turns on again. That is, the lighting circuit 60 operates in the critical mode.

The control unit 30 converts the light source current flowing through the light source 20 into a voltage with the resistor R1 and detects it from the IFB terminal. The control unit 30 changes the ON period of the second switching element Q2 so that the detection voltage from the IFB terminal becomes the target voltage. As a result, the target constant current flows through the light source 20.

The feedback of the light source current is performed by detecting the peak current. In the back converter circuit, a current flows through the light source 20 both at the time of turn-on and at the time of turn-off. When operating in the critical mode, the current _Iavg flowing through the light source 20 can be obtained by Eq. (7).

In turn-on period _{T on,} the current flowing through the inductor L1 _{I o-p} (on) is expressed by equation (8).

_{The current I op} (off) at which the inductor L1 is discharged during the turn-off period To _off is represented by the equation (9).

Since of the critical mode, equation (10) holds.

For example, the forward voltage of the light source 20 is 100 V, the forward current is 250 mA, and the inductor L1 is 1 mH. In this case, the switching frequency is _{147kHz, T on} is _{1.8μs, T off} is _{5.0μs, I o-p} will be 0.5A.

In this embodiment, the input voltage _{V in} the case has been described where two conditions of DC48V and 380 V DC. Input voltage V _in the lighting device 10 in other values is operable. For example, the input voltage _{V in} good even 340V. At this time, the lighting circuit 60 operates as a back converter circuit. Operating conditions at this time, when the forward voltage of the light source 20 100 V, 250 mA forward current, the inductor L1 and 1 mH, the switching frequency is _{141kHz, T on} is _{2.1μs, T off} is 5.0μs, _{I o -P} is 0.5A.

In the present embodiment, when the input voltage Vin is _in the range of DC48V to DC380V, a constant output specification can be realized by one lighting device 10. The output specifications include the forward voltage and forward current of the light source 20.

In general, the input voltage V _in from the DC power source DC is, different voltage values to fit the power consumption or application is envisioned. In addition to the commonly used voltage of DC 48V or less, DC 380V may be used, for example, in an electric vehicle or a photovoltaic power generation system.

In this embodiment, selectively circuits that operate in accordance with the input voltage V _in. As a result, the light source 20 can be turned on in response to a plurality of input voltage values. In this embodiment, it is possible to correspond to the input voltage V _in a wide range at the lighting apparatus 10 of one. Therefore, it is not necessary to prepare a dedicated lighting fixture for each input voltage value, and an increase in the number of models can be suppressed.

In the present embodiment, the second switching element Q2 is maintained in the ON state during the step-up operation, and is switched so that the light source current matches the target value during the step-down operation. The second switching element Q2 can also operate as a protection circuit in the event of an abnormality.

Control unit 30, when the input voltage V _in is not within a predetermined range, may maintain a second switching element Q2 in the off state. Further, the control unit 30 may maintain the second switching element Q2 in the off state when the current flowing through the light source 20 or the voltage generated in the light source 20 is not in a predetermined range. Here, the current flowing through the light source 20 can be detected by the resistor R1. The voltage generated in the light source 20 is, for example, the voltage across the light source 20.

In this way, when the control unit 30 _{detects an abnormality in} the input voltage Vin, the light source current, the voltage of the light source 20, or the like, the second switching element Q2 may be turned off. As a result, the current flowing in the lighting device 10 can be blocked. Therefore, it is possible to prevent a failure of the lighting device 10 or the light source 20.

In this embodiment, the boost chopper circuit and the back converter circuit are controlled in the critical mode. The boost chopper circuit and the back converter circuit may operate in any of the discontinuous mode, the critical mode, and the continuous mode.

Further, the control unit 30 detected the peak current and performed feedback control. The control unit 30 may perform feedback control by detecting a voltage obtained by smoothing the voltage generated in the resistor R1 with a capacitor. In this case as well, the equations (1) and (7) hold.

Further, the control unit 30 controls the lighting circuit 60 so that the same light source current can be obtained depending on whether the lighting circuit 60 is stepped up or stepped down. As an example of this modification, the light source current may be different between the step-up operation and the step-down operation.

In this embodiment, the control unit 30 according to the input voltage V _in, switch the operation of the lighting circuit 60 between the step-up operation and the step-down operation. Control unit 30, the input voltage V _in to the step-up operation the lighting circuit 60 when the first voltage. The control unit 30 includes an input voltage V _in to step-down operation of the lighting circuit 60 when the second voltage higher than the first voltage. As an example, the first voltage is 48V and the second voltage is 380V. The second voltage may be 340V. The first voltage and the second voltage may be changed according to the input voltage V _in of the DC power source whose use is contemplated.

Control unit 30, a lighting circuit 60 is boosting operation if: the input voltage V _in a predetermined threshold value, the lighting circuit 60 when the input voltage V _in is greater than the threshold value may be step-down operation. The threshold is, for example, 48 V or more and less than 340 V.

Further, the lighting circuit 60 operates as a step-up chopper circuit during the step-up operation and as a back converter circuit during the step-down operation. In boost operation, the lighting circuit 60 may operate as a step-up circuit capable of an input voltage V _in is not limited to the step-up chopper circuit. Further, during the step-down operation, the lighting circuit 60 may be operated as a possible step-down circuit input voltage V _in is not limited to buck converter circuit.

Further, in the present embodiment, the step-up circuit and the step-down circuit of the lighting circuit 60 share some circuit components. As a result, it is possible to suppress an increase in the size of the lighting circuit 60. Specifically, the boost chopper circuit and the back converter circuit share the inductor L1. As a modification of this, the step-up circuit and the step-down circuit may be provided separately.

The technical features described in this embodiment may be used in combination as appropriate.

10 lighting device, 20 light source, 21 light emitting element, 30 control unit, 40 control power supply circuit, 50 step-down circuit, 60 lighting circuit, 61, 62 lines, 63, 64 output end, 100 lighting fixture, C1 capacitor, C2 electrolytic capacitor, D1 1st diode, D2 2nd diode, DC DC power supply, L1 inductor, Q1 1st switching element, Q2 2nd switching element, R1, R2 resistor

Claims (9)

A lighting circuit that lights the light source by supplying input voltage from a DC power supply,
A control unit that switches the operation of the lighting circuit between a step-up operation and a step-down operation according to the input voltage.
A lighting device characterized by being provided with. The control unit is characterized in that the lighting circuit is boosted when the input voltage is the first voltage, and the lighting circuit is stepped down when the input voltage is a second voltage higher than the first voltage. The lighting device according to claim 1. The lighting device according to claim 1 or 2, wherein the lighting circuit operates as a boost chopper circuit during a step-up operation and as a back converter circuit during a step-down operation. The lighting circuit
A pair of lines that receive power from the DC power supply,
A pair of output ends that supply power to the light source,
An inductor whose one end is electrically connected to the high potential side of the pair of lines,
A first diode whose cathode is electrically connected to the one end of the inductor,
A second diode whose anode is electrically connected to the other end of the inductor and whose cathode is electrically connected to the high potential side of the pair of output ends.
It has a first terminal, a second terminal, and a first control terminal for switching on / off between the first terminal and the second terminal, and the first terminal is electrically connected to the other end of the inductor. The first terminal is electrically connected to the anode of the first diode and the low potential side of the pair of output terminals, and the first control terminal is electrically connected to the control unit. Switching element and
It has a third terminal, a fourth terminal, and a second control terminal for switching on / off between the third terminal and the fourth terminal, and the third terminal is on the low potential side of the pair of output terminals. The second switching element is electrically connected to, the fourth terminal is electrically connected to the low potential side of the pair of lines, and the second control terminal is electrically connected to the control unit.
The lighting device according to any one of claims 1 to 3, wherein the lighting device comprises. The fourth aspect of claim 4, wherein the control unit operates the lighting circuit as a step-up chopper circuit by keeping the second switching element on and turning the first switching element on and off. Lighting device. The fourth or fifth aspect of the present invention, wherein the control unit operates the lighting circuit as a back converter circuit by keeping the first switching element in an off state and turning the second switching element on and off. Lighting device. The lighting device according to any one of claims 4 to 6, wherein the control unit keeps the second switching element in an off state when the input voltage is not in a predetermined range. Any of claims 4 to 7, wherein the control unit keeps the second switching element in an off state when the current flowing through the light source or the voltage generated by the light source is not in a predetermined range. The lighting device according to item 1. The lighting device according to any one of claims 1 to 8.
With the light source
A lighting fixture characterized by being equipped with.

Images