JP7484522B2 - Lighting fixture, connection unit and lighting device - Google Patents

Description

This disclosure relates to lighting fixtures, connection units, and lighting devices.

Patent Document 1 discloses an LED driver that converts AC input power into DC output power and supplies it to an LED load. This LED driver includes a switching element that is on/off controlled, a ripple current reduction unit that is connected in series to the LED load and reduces the current ripple flowing through the LED load, and a control circuit. The control circuit controls the DC output power to a predetermined value by controlling the on/off of the switching element based on a feedback voltage at the connection point between the LED load and the ripple current reduction unit. The ripple current reduction unit has a feedback type constant current control circuit that variably controls the impedance.

Japanese Patent No. 5110197

In the LED driving device shown in Patent Document 1, adding a ripple current reduction unit may increase manufacturing costs. In addition, there is a risk of loss occurring due to the product of the ripple voltage and the current flowing through the light source, reducing circuit efficiency. Furthermore, if the LED driving device is installed in an environment where a ripple countermeasure function is already built in, the ripple current reduction unit may not be necessary.

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a lighting fixture, connection unit, and lighting device that can switch between having and not having a ripple suppression function.

A lighting fixture according to the present disclosure comprises a lighting device, a light source module, and a connection unit. The lighting device comprises a pair of output terminals, a feedback terminal, a lighting circuit that generates power by turning a first switching element on and off and outputs the power from the pair of output terminals to light a light source, and a first control circuit that controls the on and off of the first switching element so that a feedback value input from the feedback terminal matches a predetermined first reference value. The light source module comprises a first light source terminal connected to one of the pair of output terminals, the second light source terminal, and the light source connected between the first light source terminal and the second light source terminal. The connection unit comprises a first connection terminal connected to the feedback terminal and that outputs the feedback value, a second connection terminal connected to the other of the pair of output terminals, and a current detection unit connected in series to the light source via the second light source terminal . The connection unit is selectable between a connection unit without a ripple suppression function and a connection unit with a ripple suppression function .

The connection unit according to the present disclosure comprises a current detection unit, a switching element connected in series with the current detection unit, a control circuit that controls the on/off of the switching element so that the detection value of the current detection unit matches a predetermined reference value, a first connection terminal that outputs a feedback value used for feedback control in the lighting device, a second connection terminal connected to the output terminal of the lighting device, a third connection terminal that supplies current to the series circuit formed by the current detection unit and the switching element, and a fourth connection terminal to which power is supplied for the control circuit , and is selectably connected to a connection unit that does not have a ripple suppression function for the lighting device .

The lighting device according to the present disclosure comprises a pair of output terminals, a feedback terminal, a lighting circuit that generates power by turning a switching element on and off and outputs the power from the pair of output terminals to light a light source, and a control circuit that controls the on and off of the switching element so that a feedback value input from the feedback terminal matches a predetermined reference value , and is configured such that the feedback value can be selected between a feedback value from a connection unit that does not have a ripple suppression function and a feedback value from a connection unit that has a ripple suppression function .

In the lighting fixture disclosed herein, the ripple suppression function can be switched on or off depending on the type of connection unit.

The connection unit disclosed herein allows you to switch between having and not having the ripple suppression function by connecting the connection unit to the lighting device.

In the lighting device disclosed herein, the ripple suppression function can be switched on or off depending on the type of connection unit connected to the lighting device.

FIG. 2 is a circuit block diagram of a lighting fixture not having a ripple suppression function according to the first embodiment. 1 is a circuit block diagram of a lighting fixture having a ripple suppression function according to a first embodiment. FIG. FIG. 11 is a circuit block diagram of a lighting fixture according to a second embodiment.

The lighting fixture, connection unit, and lighting device according to each embodiment of the present invention will be described with reference to the drawings. The same or corresponding components will be given the same reference numerals, and repeated description may be omitted. In addition, hereinafter, when the term "connection" is used, it is assumed that this includes electrical connection.

Embodiment 1.
1 is a circuit block diagram of a lighting fixture 100 having no ripple suppression function according to embodiment 1. The lighting fixture 100 includes a lighting device 1, a light source module 90, and a connection unit 50.

The light source module 90 includes a first light source terminal 91, a second light source terminal 92, and a plurality of light sources 93. The plurality of light sources 93 are connected between the first light source terminal 91 and the second light source terminal 92. The light sources 93 are light-emitting elements such as LEDs. The plurality of light sources 93 are connected in series. The plurality of light sources 93 may also be connected in parallel or in series-parallel. Furthermore, it is sufficient that the light source module 90 includes at least one light source 93.

The connection unit 50 includes a first connection terminal 71, a second connection terminal 72, and a current detection unit 51 connected between the first connection terminal 71 and the second connection terminal 72. In this embodiment, the current detection unit 51 is an LED current detection resistor. The current detection unit 51 is not limited to a resistive element, and may be any element capable of detecting the current flowing through the light source module 90.

The lighting device 1 has a pair of input terminals 81, 82, a pair of output terminals 31, 32, and a feedback terminal 33 as connection points with the outside. The lighting device 1 also has a rectifier circuit 8, a capacitor 9, a flyback circuit 10, a snubber circuit 20, a control circuit 40, capacitors 42, 43, 44, and an electrolytic capacitor 13.

In the lighting device 1, an AC power source 7 is connected to the rectifier circuit 8 via input terminals 81 and 82. The AC power source 7 is also called a commercial power source. A capacitor 9 is connected between the output terminals of the rectifier circuit 8.

The flyback circuit 10 is composed of a transformer 11, a diode 12, and a switching element Q1. The flyback circuit 10 converts the pulsating voltage supplied from the rectifier circuit 8 into a DC voltage by switching operation. The flyback circuit 10 is a lighting circuit that generates power by turning on and off the switching element Q1, and outputs this power from a pair of output terminals 31, 32 to light the light source 93.

The switching element Q1 is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The switching element Q1 has a first terminal, a second terminal, and a control terminal. When the switching element Q1 is a MOSFET, the first terminal is a drain terminal, the second terminal is a source terminal, and the control terminal is a gate terminal. The control terminal is a terminal for switching between the first and second terminals. The first terminal of the switching element Q1 is connected to the anode of the diode 23. The second terminal of the switching element Q1 is connected to the negative electrode of the capacitor 9. The control terminal of the switching element Q1 is connected to the control circuit 40.

One end of the primary side of the transformer 11 is connected to the positive electrode of the capacitor 9. The other end of the primary side of the transformer 11 is connected to the first terminal of the switching element Q1. One end of the secondary side of the transformer 11 is connected to the anode of the diode 12. The cathode of the diode 12 is connected to the output terminal 31. An electrolytic capacitor 13 is connected between the other end of the secondary side of the transformer 11 and the cathode of the diode 12. The electrolytic capacitor 13 smoothes the output of the flyback circuit.

A snubber circuit 20 is connected to the capacitor 9. The snubber circuit 20 is composed of a resistor 21, a capacitor 22, and a diode 23. One end of the resistor 21 and the positive electrode of the capacitor 22 are connected to the positive electrode of the capacitor 9. The other end of the resistor 21 and the negative electrode of the capacitor 22 are connected to the cathode of the diode 23. In the flyback circuit 10, when the pulsating voltage is converted to a DC voltage, the leakage inductance of the transformer 11 causes energy that is not transmitted to the secondary side of the transformer 11 to be generated as a kickback voltage across both ends of the switching element Q1. The snubber circuit 20 suppresses this kickback voltage.

The output terminal 31 of the lighting device 1 is connected to the first light source terminal 91. In other words, the output terminal 31 is connected to the anode side of the light source module 90. The second light source terminal 92 provided on the cathode side of the light source module 90 is connected to the first connection terminal 71 of the connection unit 50 and the feedback terminal 33 of the lighting device 1. The current detection unit 51 is connected in series to the light source 93 via the second light source terminal 92. The second connection terminal 72 of the connection unit 50 is connected to the output terminal 32 of the lighting device 1. The output terminal 32 is connected to the negative output of the flyback circuit 10.

The control circuit 40 includes an error amplifier 41 and a drive circuit 45. The feedback terminal 33 is connected to one input terminal of the error amplifier 41. A capacitor 42 is connected between one input terminal of the error amplifier 41 and the output terminal 32. A capacitor 43 is connected between the other input terminal of the error amplifier 41 and the output terminal 32. A capacitor 44 is connected between the output terminal of the error amplifier 41 and the output terminal 32. A drive circuit 45 is connected to the output terminal of the error amplifier 41. The drive circuit 45 is connected to the control terminal of the switching element Q1. The control circuit 40 controls the on/off of the switching element Q1. The control circuit 40 is formed, for example, from a microcomputer, an integrated circuit, etc.

The output current of the flyback circuit 10 flows in the following order: output terminal 31, light source module 90, current detection unit 51, and output terminal 32. The current flowing through the light source module 90 is converted to a voltage by the current detection unit 51. The first connection terminal 71 is connected to the feedback terminal 33. The first connection terminal 71 outputs a feedback value to the feedback terminal 33. In this embodiment, the feedback value is the detection value of the current detection unit 51. In other words, the feedback value is the voltage generated in the current detection unit 51.

The control circuit 40 detects the feedback value input from the feedback terminal 33 using the error amplifier 41. The control circuit 40 charges the capacitor 43 by itself. As a result, the control circuit 40 generates a first reference value, which is a reference voltage, at the other input terminal of the error amplifier 41. The error amplifier 41 compares this feedback value with the first reference value, and performs a switching operation via the drive circuit 45 so that the error becomes zero. In this way, the control circuit 40 controls the on/off of the switching element Q1 so that the feedback value matches the predetermined first reference value. Therefore, the flyback circuit 10 is constant current controlled.

The capacitor 44 is provided for phase compensation. This allows feedback control to be performed so that the feedback period is equal to or shorter than the period of the AC power supply 7.

In this embodiment, the flyback circuit 10 generates a DC voltage by power factor correction. Therefore, a ripple voltage derived from the commercial power supply is superimposed between the output terminals 31 and 32 of the flyback circuit 10. In other words, a ripple voltage is superimposed on both ends of the light source module 90 and the current detection unit 51. Therefore, the current flowing through the light source 93 is a current accompanied by a ripple. This ripple current varies depending on the capacity of the electrolytic capacitor 13. However, in order to make the ripple voltage zero, a large-capacity electrolytic capacitor 13 is generally required. For this reason, it is difficult to sufficiently remove the ripple using the electrolytic capacitor 13.

Figure 2 is a circuit block diagram of a lighting fixture 200 having a ripple suppression function according to the first embodiment. The lighting fixture 200 is obtained by replacing the connection unit 50 of the lighting fixture 100 with a connection unit 250. The same lighting device 1 and light source module 90 are used in the lighting fixture 100 and the lighting fixture 200.

The connection unit 250 includes a switching element Q2, a current detection unit 52, a control circuit 53, resistors 55 and 56, and a capacitor 57. The current detection unit 52 is an LED current detection resistor. The current detection unit 52 is not limited to a resistive element, and may be any element capable of detecting the current flowing through the switching element Q2. The switching element Q2 is, for example, a MOSFET.

The connection unit 250 includes a first connection terminal 71, a second connection terminal 72, a third connection terminal 73, and a fourth connection terminal. The first connection terminal 71 is connected to the feedback terminal 33. The second connection terminal 72 is connected to the output terminal 32. The third connection terminal 73 is connected to the second light source terminal 92. The fourth connection terminal 74 is connected to the output terminal 31 and the first light source terminal 91. The fourth connection terminal 74 is also connected to the Vcc terminal of the control circuit 53. The fourth connection terminal 74 receives power from the lighting device 1 to the control circuit 53.

The switching element Q2 and the current detection unit 52 are connected in series to form a series circuit. The first terminal of the switching element Q2 is connected to the cathode side of the light source module 90 via the third connection terminal 73. In this manner, the third connection terminal 73 supplies current to the series circuit formed by the current detection unit 52 and the switching element Q2. One end of the current detection unit 52 is connected to the second terminal of the switching element Q2. The other end of the current detection unit 52 is connected to the second connection terminal 72. A series circuit of resistors 55 and 56 is connected in parallel to the series circuit formed by the switching element Q2 and the current detection unit 52. The first connection terminal 71 is connected to the connection point of the resistors 55 and 56.

The resistors 55 and 56 form a voltage divider circuit. The connection point of the resistors 55 and 56 is connected to the feedback terminal 33 via the first connection terminal 71. The first connection terminal 71 outputs a feedback value used for feedback control in the lighting device 1. The first connection terminal 71 outputs a voltage corresponding to the voltage across the series circuit formed by the current detection unit 52 and the switching element Q2 to the feedback terminal 33 as a feedback value. In other words, the resistors 55 and 56 divide the drain voltage of the switching element Q2 and input it to the feedback terminal 33. Therefore, the flyback circuit 10 operates at a constant voltage so that the drain voltage of the switching element Q2 is constant.

The control circuit 53 has an error amplifier 54. The second terminal of the switching element Q2 is connected to one input terminal of the error amplifier 54. A capacitor 57 is connected between the other input terminal of the error amplifier 54 and a second connection terminal 72. The control terminal of the switching element Q2 is connected to the output terminal of the error amplifier 54. The control circuit 53 generates the second reference value by charging the capacitor 57 itself.

The control circuit 53 controls the on/off of the switching element Q2 so that the detection value of the current detection unit 52 matches a predetermined second reference value. In other words, the error amplifier 54 adjusts the voltage applied to the control terminal of the switching element Q2 so that the current flowing through the current detection unit 52 matches a predetermined value. As a result, the control circuit 53 operates the switching element Q2 in the active region and performs constant current control by adjusting the impedance.

In order to improve the power factor of the flyback circuit 10, a ripple voltage is applied to both ends of the series circuit formed by the light source module 90, the switching element Q2, and the current detection unit 52. Here, the connection unit 250 controls the impedance of the switching element Q2. By controlling the impedance of the connection unit 250, the voltage applied to both ends of the light source module 90 becomes constant, and the current flowing through the light source module 90 becomes constant. In other words, by the switching element Q2 handling the ripple voltage, the voltage applied to the light source module 90 becomes constant, and the ripple of the LED current is suppressed. Therefore, the ripple current can be suppressed.

As described above, in this embodiment, the lighting device 1 and the light source module 90 are common, and the presence or absence of the ripple suppression function can be switched by selecting the connection unit 50, 250. The lighting fixture 100 in which the connection unit 50 is used is not provided with a ripple suppression function. The lighting fixture 200 in which the connection unit 250 is used is provided with a ripple suppression function.

The lighting fixture 100 using the connection unit 50 does not have a ripple suppression function, so it is possible to suppress the decrease in circuit efficiency due to losses caused by ripple suppression. This loss corresponds to the product of the ripple voltage and the LED current. Therefore, a highly efficient and low-cost lighting fixture 100 can be realized. In environments where equipment affected by lighting, such as surveillance cameras, is used, a ripple suppression function may be built in beforehand. In such environments, the connection unit 50 can be particularly selected.

In this embodiment, the ripple suppression function can be switched on or off depending on the type of connection unit. Therefore, there is no need to provide a switching mechanism for the ripple suppression function in the lighting device, and the lighting device 1 can be manufactured at low cost. Furthermore, in the lighting fixtures 100 and 200 of this embodiment, the lighting device 1 and light source module 90 can be standardized. Therefore, there is no need to develop multiple lighting devices 1 depending on whether or not they have the ripple suppression function, and the number of models can be reduced. This allows development costs to be reduced.

In addition, the output current of the lighting device 1 can be adjusted by adjusting the constants of the components of the connection units 50 and 250. In adjusting the constants, for example, the resistance value of the resistors of the connection units 50 and 250 is adjusted. This eliminates the need to classify the lighting device 1 according to the magnitude of the output current. Therefore, the lighting device 1 and the light source module 90 can be further standardized.

The lighting device 1 of this embodiment also includes output terminals 31, 32 and a feedback terminal 33. By providing these terminals in the lighting device 1, it is possible to switch between the presence and absence of a ripple suppression function depending on the type of connection unit connected to the lighting device 1. In addition, the control or output power of the lighting device 1 can be switched depending on the type of connection unit.

In addition, the output terminals 31, 32, the feedback terminal 33, the first light source terminal 91, and the second light source terminal 92 are structured to be connectable and disconnectable to other terminals. In addition, the first connection terminal 71, the second connection terminal 72, the third connection terminal 73, and the fourth connection terminal 74 are also structured to be connectable and disconnectable to other terminals. As a result, the connection unit 50 is detachably provided to the lighting device 1 and the light source module 90 by the first connection terminal 71 and the second connection terminal 72. Similarly, the connection unit 250 is detachably provided to the lighting device 1 and the light source module 90 by the first connection terminal 71, the second connection terminal 72, the third connection terminal 73, and the fourth connection terminal 74. Therefore, the ripple suppression function can be easily switched on and off.

In FIG. 1, the second light source terminal 92 is connected to the wiring connecting the feedback terminal 33 and the first connection terminal 71. As a variation of this, the connection unit 50 may further have a connection terminal for connecting the second light source terminal 92 and the current detection unit 51.

In this embodiment, the lighting circuit is a flyback circuit. The lighting circuit may be any other switching circuit, such as a buck-boost circuit or a buck converter circuit, as long as it converts pulsating current to direct current.

The connection unit is not limited to the one shown in Figs. 1 and 2. Other circuits may be used as long as the connection unit can be connected to the lighting device 1 and the light source module 90 to supply current to the light source module 90 and function as a light source.

When connected to the connection unit 50, the lighting device 1 operates at a constant current, and when connected to the connection unit 250, the lighting device 1 operates at a constant voltage. This is not limiting, and the lighting device 1 may operate at a constant current when connected to the connection unit 250. In other words, the LED current value may be fed back from the first connection terminal 71 to the feedback terminal 33.

These modifications can be applied as appropriate to the lighting fixtures, connection units, and lighting devices according to the following embodiments. Note that the lighting fixtures, connection units, and lighting devices according to the following embodiments have many things in common with embodiment 1, so the following description will focus on the differences from embodiment 1.

Embodiment 2.
3 is a circuit block diagram of a lighting fixture 300 according to the second embodiment. The lighting fixture 300 of the present embodiment differs from the lighting fixtures 100 and 200 in the configuration of a connection unit 350. The lighting device 1 and the light source module 90 are the same as those of the first embodiment.

In addition to the configuration of the connection unit 250, the connection unit 350 further includes a regulator circuit 58, voltage dividing resistors 59 and 60, a switching element Q3, and a dimming IF (Interface) circuit 62. The regulator circuit 58 receives power from the lighting device 1 via a fourth connection terminal 74 and generates a constant voltage. A series circuit of voltage dividing resistors 59 and 60 is connected between the regulator circuit 58 and the second connection terminal 72. The first terminal of the switching element Q3 and the error amplifier 54 are connected to the connection point of the voltage dividing resistors 59 and 60. The second terminal of the switching element Q3 is connected to the second connection terminal 72. The control terminal of the switching element Q3 is connected to the dimming IF circuit 62. The control terminal of the switching element Q3 is a terminal for switching between the first and second terminals.

The second reference value is input to the error amplifier 54 through the voltage dividing resistors 59 and 60. A dimming signal is input from an external dimmer 63. The connection unit 350 may include a dimming terminal 75 that receives the dimming signal. The dimming signal is detected by the dimming IF circuit 62. The dimming IF circuit 62 generates a PWM (Pulse Width Modulation) signal with a predetermined duty in response to the dimming signal. The switching element Q3 is turned on and off in response to the PWM signal. This adjusts the second reference value to a value in response to the dimming signal. Therefore, the LED current can be controlled to a value in response to the dimming signal. In this way, the second reference value may be changed in response to an external signal.

The technical features described in each embodiment may be used in any suitable combination.

1 lighting device, 7 AC power supply, 8 rectifier circuit, 9 capacitor, 10 flyback circuit, 11 transformer, 12 diode, 13 electrolytic capacitor, 20 snubber circuit, 21 resistor, 22 capacitor, 23 diode, 31 output terminal, 32 output terminal, 33 feedback terminal, 40 control circuit, 41 error amplifier, 42 capacitor, 43, 44 capacitor, 45 drive circuit, 50 connection unit, 51 current detection unit, 52 current detection unit, 53 control circuit, 54 error amplifier, 55, 56 resistor, 57 capacitor, 58 regulator circuit, 59, 60 voltage dividing resistor, 62 dimming IF circuit, 63 dimmer, 71 first connection terminal, 72 second connection terminal, 73 third connection terminal, 74 fourth connection terminal, 75 dimming terminal, 81, 82 input terminal, 90 light source module, 91 first light source terminal, 92 Second light source terminal, 93 light source, 100, 200 lighting fixture, 250 connection unit, 300 lighting fixture, 350 connection unit, Q1, Q2, Q3 switching element

Claims (12)

The lighting device includes a lighting device, a light source module, and a connection unit.
The lighting device includes:
A pair of output terminals;
A feedback terminal;
a lighting circuit that generates power by turning on and off a first switching element and outputs the power from the pair of output terminals to light the light source;
a first control circuit that controls on/off of the first switching element so that a feedback value input from the feedback terminal matches a predetermined first reference value;
Equipped with
The light source module includes:
a first light source terminal connected to one of the pair of output terminals;
A second light source terminal;
the light source connected between the first light source terminal and the second light source terminal;
Equipped with
The connection unit includes:
a first connection terminal connected to the feedback terminal and configured to output the feedback value;
a second connection terminal connected to the other of the pair of output terminals;
a current detection unit connected in series to the light source via the second light source terminal;
Equipped with
A lighting fixture characterized in that , as the connection unit, a connection unit not provided with a ripple suppression function and a connection unit provided with a ripple suppression function are selectively provided . The lighting fixture according to claim 1, characterized in that the connection unit is detachably provided to the lighting device and the light source module. In the connection unit not provided with the ripple suppression function, the current detection unit is connected between the first connection terminal and the second connection terminal,
3. The lighting fixture according to claim 1, wherein the first control circuit performs constant current control on the lighting circuit so that the feedback value, which is a detection value of the current detection unit, coincides with the first reference value. The connection unit provided with the ripple suppression function is
A second switching element connected in series with the current detection unit;
a second control circuit that controls the second switching element to be turned on and off so that a detection value of the current detection unit coincides with a second reference value that is determined in advance;
3. The lighting device according to claim 1, further comprising: The lighting device according to claim 4, characterized in that the first connection terminal outputs a voltage corresponding to the voltage across both ends of a series circuit formed by the current detection unit and the second switching element as the feedback value. The lighting device according to claim 4 or 5, characterized in that the connection unit controls the impedance of the second switching element. The lighting device according to any one of claims 4 to 6, characterized in that the second reference value is changed in response to an external signal. The connection unit includes:
a third connection terminal connected to the second light source terminal;
a fourth connection terminal to which power for the second control circuit is supplied from the lighting device;
8. A lighting device according to claim 4, further comprising: A current detection unit;
A switching element connected in series with the current detection unit;
a control circuit that controls the on/off of the switching element so that a detection value of the current detection unit coincides with a predetermined reference value;
a first connection terminal for outputting a feedback value used for feedback control in the lighting device;
A second connection terminal connected to an output terminal of the lighting device;
a third connection terminal that supplies a current to a series circuit formed by the current detection unit and the switching element;
a fourth connection terminal to which power is supplied to the control circuit;
Equipped with
A connection unit capable of being selectively connected to a connection unit not provided with a ripple suppression function for the lighting device . The connection unit according to claim 9, characterized in that the first connection terminal outputs a voltage corresponding to the voltage across the series circuit as the feedback value. The connection unit according to claim 9 or 10, characterized in that the reference value is changed in response to an external signal. A pair of output terminals;
A feedback terminal;
a lighting circuit that generates power by turning on and off a switching element and outputs the power from the pair of output terminals to light the light source;
a control circuit that controls the on/off of the switching element so that a feedback value input from the feedback terminal matches a predetermined reference value;
Equipped with
A lighting device characterized in that the feedback value is selectable between a feedback value from a connection unit not provided with a ripple suppression function and a feedback value from a connection unit provided with a ripple suppression function .

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