JP2015176666A - Lighting device and illuminating fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device and an illuminating fixture capable of detecting attachment/detachment of a light source module with accuracy in an H-bridge circuit.SOLUTION: A lighting device 10 comprises: a rectification circuit 6 connected with an AC power supply 4 and configured to rectify an AC voltage; an H-bridge circuit 14 connected with the rectification circuit 6; a capacitor C1 provided at an output side of the H-bridge circuit 14; a voltage detection circuit 16 configured to detect a voltage between output terminals 10a and 10b; a discharge circuit 18 that can conduct both ends of the capacitor C1; a diode D3 that applies a current from one end of the capacitor C1 toward the positive electrode output terminal 10a; and a detection power supply circuit 19 configured to apply a voltage between the output terminals 10a and 10b. The positive electrode output terminal 10a is connected with one end of the capacitor C1, and the negative electrode output terminal 10b is connected with the other end of the capacitor C1. When the voltage detected by the voltage detection circuit 16 becomes a threshold or more, the discharge circuit 18 discharges the capacitor C1, and the detection power supply circuit 19 applies the voltage between the output terminals 10a and 10b.

Description

  The present invention relates to a lighting device and a lighting fixture.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-28222, a luminaire that can detect attachment / detachment of a light source module including an LED element is known.

JP 2012-28222 A

  Various converter circuits are mounted on a lighting device included in the lighting fixture, and a step-down DCDC converter is mounted on the conventional lighting fixture. By the way, the inventor of the present application has developed a technology that uses an H-bridge circuit as a power supply circuit of a lighting device. The capacitor attached to the output side of the H-bridge circuit is required to have a somewhat large capacity. By providing such a capacitor having a large capacity, there is a problem that the detection accuracy is reduced due to the charge of the capacitor when the reconnection of the light source module is detected.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a lighting device and a lighting fixture that can accurately detect the attachment / detachment of a light source module in an H-bridge circuit.

  A lighting device according to the present invention includes a first output terminal, a second output terminal, an AC power source, a rectifier circuit that rectifies an AC voltage, an H bridge circuit that is connected to the rectifier circuit, and the H bridge circuit. A voltage is detected between the first and second output terminals, provided on the output side, one end of which is electrically connected to the first output terminal and the other end is electrically connected to the second output terminal. A voltage detection circuit; a rectifying element provided in a direction in which a current flows in one direction from the one end of the capacitor toward the first output terminal; and the one end and the other end of the capacitor so as to discharge the capacitor And a power supply circuit that applies a voltage between the first and second output terminals, and when the voltage detected by the voltage detection circuit exceeds a threshold value, the capacitor is connected to the discharge circuit by the discharge circuit. Discharge Applying a voltage between the first and second output terminals in the power supply circuit.

  A lighting fixture according to the present invention includes: a light source including a light emitting element and a resistor connected in parallel to the light emitting element; and a lighting device that includes first and second output terminals connected to the light source and lights the light emitting element. The lighting device is provided on the output side of the H bridge circuit, connected to an AC power source and rectifies an AC voltage, an H bridge circuit connected to the rectifier circuit, and one end of the first output terminal. And a capacitor whose other end is electrically connected to the second output terminal, a voltage detection circuit for detecting a voltage between the first and second output terminals, and one end of the capacitor from the first. A voltage is applied between the first and second output terminals, a rectifying element provided in a direction to flow current in one direction toward the output terminal, a discharge circuit capable of conducting both ends of the capacitor so as to discharge the capacitor, and the first and second output terminals. Apply It includes a power supply circuit, and a voltage is applied between the voltage voltage detected by the detection circuit to discharge the capacitor in the discharge circuit If becomes equal to or larger than the threshold value the power supply circuit in the first and second output terminals.

  According to the present invention, the capacitor can be discharged in accordance with the removal of the light source module and the light source module attachment / detachment detection using the voltage of the power supply circuit can be performed. Therefore, the attachment / detachment of the light source module can be accurately detected even in the H-bridge circuit. be able to.

It is a circuit diagram of the lighting device and lighting fixture concerning an embodiment of the invention. It is a circuit diagram of the lighting device concerning a modification of an embodiment, and a lighting fixture provided with the same. It is a circuit diagram of the lighting device concerning a modification of an embodiment, and a lighting fixture provided with the same. It is a circuit diagram of the lighting device concerning a modification of an embodiment, and a lighting fixture provided with the same.

  FIG. 1 is a circuit diagram of a lighting device and a lighting fixture 1 according to an embodiment of the present invention. The lighting fixture 1 includes a light source module 2 and a lighting device 10. The light source module 2 includes at least one LED element 2a and a resistor RL connected in parallel to the LED element 2a. The lighting device 10 includes output terminals 10a and 10b connected to the light source module 2, converts the AC voltage of the AC power supply 4 into a DC voltage, and typically turns on the LED element 2a by constant current control. The light source module 2 may include a plurality of LED elements 2a connected in series, parallel, or a combination of series and parallel, and an organic EL element may be used instead of the LED element 2a. The configuration in which the resistor RL is connected in parallel to the LED element 2a as in the light source module 2 is typically employed in straight tube type LED illumination. In the straight tube type illumination, detection of attachment / detachment of the light source module (so-called lamp) Detection) is essential.

  The lighting device 10 includes a positive electrode output terminal 10a and a negative electrode output terminal 10b (hereinafter, these may be collectively referred to as “output terminals 10a and 10b” for convenience). The lighting device 10 includes a rectifier circuit 6 that is typically a diode bridge that is connected to the AC power source 4 and rectifies an AC voltage, and an H-bridge circuit 14 that is connected to the rectifier circuit 6 and receives a direct current that has been full-wave rectified. I have. A power switch (not shown) is interposed between the AC power supply 4 and the rectifier circuit 6.

  The H bridge circuit 14 includes a switching element Q1, a diode D1, an inductor L1, a diode D2, a switching element Q2, and a resistor R1. Although the switching elements Q1 and Q2 use MOSFETs, the present invention is not limited to this, and other switching elements such as IGBTs and bipolar transistors may be used. The first terminal (drain in this embodiment) of the switching element Q1 is connected to the high-voltage side output terminal of the rectifier circuit 6. The second terminal (source in the present embodiment) of the switching element Q1 is connected to the cathode of the diode D1. The anode of the diode D1 is connected to the low-voltage side output terminal of the rectifier circuit 6. One end of the inductor L1 is connected to a connection point between the second terminal (source in the present embodiment) of the switching element Q1 and the cathode of the diode D1. The other end of the inductor L1 is connected to a connection point between the anode of the diode D2 and the first terminal (drain in this embodiment) of the switching element Q2. A second terminal (a source in the present embodiment) of the switching element Q2 is grounded via a resistor R1. The cathode of the diode D2 is connected to one end of the capacitor C1. One end of the resistor R1 is connected to the anode of the diode D1, and the other end of the resistor R1 is connected to the source of the switching element Q2. Switching is realized by supplying a drive signal from the driver circuit 20 to the control terminals (gates in the present embodiment) of the switching elements Q1 and Q2. The driver circuit 20 receives the control signal from the microcomputer 22 and generates a drive signal. The H bridge circuit 14 can be driven in three modes: a step-down mode, a step-up mode, and a step-up / step-down mode. The step-down mode is realized by turning on / off switching element Q1 and keeping switching element Q2 off. The step-up mode is realized by keeping the switching element Q1 on and turning on and off the switching element Q2. The step-up / step-down mode is realized by turning on and off both the switching element Q1 and the switching element Q2.

  On the output side of the H-bridge circuit 14, a capacitor C1 that is an electrolytic capacitor is provided. The other end of the capacitor C1 is grounded via a resistor R1. Generally, the electrolytic capacitor provided on the output side of the H-bridge circuit needs to have a certain capacity. The positive output terminal 10a is connected to one end of the capacitor C1, and the negative output terminal 10b is connected to the other end of the capacitor C1. In parallel with the capacitor C1, a series circuit of a light source module 2 and a current detection resistor R2 for detecting the current of the light source module 2 is provided.

  The lighting device 10 includes a voltage detection circuit 16 that detects a voltage between the output terminals 10a and 10b. The voltage detection circuit 16 is a voltage dividing circuit including resistors R11 and R12. One end of the resistor R11 is connected to the positive output terminal 10a, the other end of the resistor R11 is connected to one end of the resistor R12, and the voltage at the connection point between the resistor R11 and the resistor R12 is input to the microcomputer 22 as a detection voltage. The other end of the resistor R12 is grounded.

  The lighting device 10 has a function of detecting attachment / detachment of the light source module 2. First, when the light source module 2 is “detached”, that is, removed while the light source module 2 is lit, both ends of the capacitor C1 become a high voltage. The microcomputer 22 determines that the light source module 2 has been removed when the detection voltage of the voltage detection circuit 16 is equal to or higher than a predetermined “dethreshold voltage Va”. In the lighting device 10, it is preferable that the microcomputer 22 performs a protection operation according to the high voltage. In that case, the overvoltage protection operation may be performed by comparing the detection voltage of the voltage detection circuit 16 with a predetermined protection threshold voltage Vs (this may be the same value as the dethreshold voltage Va).

  Next, when the light source module 2 is “attached”, that is, connected, both ends of the resistor RL connected in parallel to the LED element 2a are connected to the positive output terminal 10a and the negative output terminal 10b. As a result, the resistor RL is attached in parallel to the resistors R11 and R12, and the voltage divided by the resistors R11 and R12, that is, the detection voltage of the voltage detection circuit 16 is lowered. The microcomputer 22 determines whether or not the load, that is, the light source module 2 is connected to the output terminals 10a and 10b by determining whether or not the detection voltage of the voltage detection circuit 16 is equal to or lower than a predetermined “arrival threshold voltage Vb”. Is detected.

The lighting device 10 includes a discharge circuit 18, a diode D3, and a detection power supply circuit 19. The discharge circuit 18 can be electrically connected to both ends of the capacitor C1 so as to discharge the capacitor C1. The discharge circuit 18 includes a series circuit of a switching element Q60, which is a MOSFET, and a resistor R63, and this series circuit is connected in parallel with the capacitor C1. Resistor R63 has one end connected to the drain of switching element Q60 and the other end connected to one end of capacitor C1. The microcomputer 22 automatically turns on / off the switching element Q60. The gate of the switching element Q60 is low, that is, off while the light source module 2 is lit. On the other hand, the switching element Q60 makes the one end and the other end of the capacitor C1 conductive when the gate is high, that is, turned on when the following (a) to (c) are satisfied.
(A) When the light source module 2 is removed (b) When the light source module 2 is removed and the protection operation is performed during lighting (c) When the lighting device 10 is off (that is, the AC power supply 4 and the rectifier circuit 6 When the power switch (not shown) is off)

The diode D3 has an anode connected to one end (high potential side terminal) of the capacitor C1 and a cathode connected to the positive electrode output terminal 10a, and a current flows in one direction from one end of the capacitor C1 toward the positive electrode output terminal 10a. Is provided. The detection power circuit 19 applies a voltage between the output terminals 10a and 10b. The detection power supply circuit 19 preferably includes a DC power supply DC that supplies a DC voltage Vd of about 20 V, a resistor R61 having one end connected to the DC power supply DC, and a Zener diode Dz1 having a cathode connected to the other end of the resistor R61. The anode includes a diode D4 connected to the anode of the Zener diode Dz1. As this DC power supply, a control power supply for supplying power to the microcomputer 22 or the like can be used. In this case, Vd = control power supply voltage Vcc. The cathode of the diode D4 is connected to the connection point between the cathode of the diode D3 and the positive output terminal 10a. A voltage Vx1 applied to the positive output terminal 10a by the detection power supply circuit 19 is expressed by the following equation. However, the Zener voltage of the Zener diode Dz1 is Vz1.
Vx1 = Vd−Vz1 (1)

  When the minimum value of the forward voltage of the light source module 2 is Vfmin, the voltage Vx1 is preferably smaller than Vfmin. Vfmin differs depending on the number of LED elements 2a connected in the light source module 2 and the connection form such as series and parallel, and the minimum value is the forward voltage Vf of one LED element 2a. Thereby, it is possible to reliably avoid the light source module 2 from being turned on by the voltage applied by the detection power supply circuit 19. Note that the detection power supply circuit 19 and the positive electrode output terminal 10a may always be connected, or for detection only when necessary by providing other switching elements, that is, only during the light source module attachment / detachment determination period after the capacitor C1 is discharged. The power supply circuit 19 and the positive electrode output terminal 10a may be connected.

  The microcomputer 22 can discharge the capacitor C1 by turning on the switching element Q60 in accordance with (more preferably at the same time) when the detection voltage of the voltage detection circuit 16 becomes equal to or higher than the dethreshold voltage Va. . At this time, the diode D3 prevents the capacitor C1 from being charged by the detection power supply circuit 19, and the detection power supply circuit 19 can apply a constant voltage between the output terminals 10a and 10b. As a result, it is possible to accurately detect whether or not the light source module 2 has been attached again by eliminating the influence of the electric charge of the capacitor C1. Further, when the light source module 2 is removed during lighting and an overvoltage is generated, the capacitor C1 is discharged quickly in response to this, so that the inrush current is supplied to the light source module 2 when the light source module 2 is reconnected in a short time. Can be prevented from flowing. When the voltage detected by the voltage detection circuit 16 becomes equal to or lower than the arrival threshold voltage Vb, the microcomputer 22 turns off the switching element Q60, thereby releasing conduction between both terminals of the capacitor C1. Thereafter, the light source module 2 can be turned on by starting the driving of the H-bridge circuit 14.

  FIG. 2 is a circuit diagram of a lighting device 110 and a lighting fixture 1 including the lighting device 110 according to a modification of the embodiment of the present invention. In this modification, the detection power supply circuit 19 in FIG. 1 is replaced with the detection power supply circuit 119 shown in FIG. The detection power supply circuit 119 has a series connection of resistors R64 and R65 having one end receiving the output voltage of the rectifier circuit 6 and the other end connected to the positive output terminal 10a, and a cathode connected to the connection point of the resistors R64 and R65. And a Zener diode Dz2 that is grounded. The voltage Vx2 supplied from the detection power supply circuit 119 may be adjusted in the same manner as Vx1 described above.

  FIG. 3 is a circuit diagram of a lighting device 210 and a lighting fixture 1 including the lighting device 210 according to a modification of the embodiment of the present invention. The lighting device 210 is obtained by providing the lighting device 10 with a switching element Q61 and a signal generation circuit 30, and replacing the microcomputer 22 with a control circuit 122. The switching element Q61 is a MOSFET, and is connected in series with the current detection resistor R2 and can switch whether or not the negative output terminal 10b is connected to the current detection resistor R2. The gate of the switching element Q61 is high, that is, turned on while the light source module 2 is lit. Further, in the switching element Q61, in the case of (a) to (c) where the switching element Q60 described above should be turned on, the gate is low, that is, turned off. By turning off, the electrical connection between the negative output terminal 10b and the current detection resistor R2 can be cut off.

  The capacitor C1 is discharged via a resistor R63 included in the discharge circuit 18. If the resistance value of the resistor R63 is low, it is preferable that the capacitor C1 can be discharged quickly. On the other hand, if the resistance is reduced, the size of the resistor R63 increases and the space on the circuit board of the lighting device 10 is limited. There is a limit. Therefore, in the lighting device 210, the other end of the capacitor C1 and the terminal of the light source module 2 are opened by cutting off the switching element Q61. By forming this open state, it is possible to prevent an inrush current from flowing through the light source module 2 even when the resistance value of the resistor R63 is high and it takes a long time to discharge and the capacitor C1 has a charge remaining.

  In the lighting device 210, the signal generation circuit 30 plays a role of detecting that the light source module 2 is reconnected. The signal generation circuit 30 generates an attachment / detachment signal S that switches according to attachment / detachment of a load (that is, the light source module 2) to the output terminals 10a, 10b based on the voltage of the negative output terminal 10b. The attachment / detachment signal S is a signal that switches between an arrival signal (for example, low) and a release signal (for example, high). In order to generate the attachment / detachment signal S, the signal generation circuit 30 includes resistors R66 and R68 and a switching element Q64. One end of the resistor R66 is connected to the connection point between the drain of the switching element Q61 and the negative output terminal 10b, the other end of the resistor R66 is connected to one end of the resistor R68, and the other end of the resistor R68 is grounded. A connection point of these resistors R66 and R68 connected in series with each other is connected to a control terminal (base in the embodiment) of the switching element Q64 which is a bipolar transistor. The emitter of the switching element Q64 is grounded, and the collector is connected to a DC power source of 5V via a resistor R70. When the light source module 2 is removed, the switching element Q64 is turned off, and the attachment / detachment signal S to the control circuit 122 is “disengaged”. When the light source module 2 is connected to the output terminals 10a and 10b, the power supply from the detection power supply circuit 19, the resistance RL in the light source module 2, and the applied voltage to the base terminal determined by the resistances R66 and R68 change. When the switching element Q64 is turned on, a collector current corresponding to the switching element Q64 flows, and the attachment / detachment signal S to the control circuit 122 is switched to “ON”. In the lighting device 210, the control circuit 122 turns off the switching element Q60 when the attachment / detachment signal S indicates “arriving”, thereby releasing conduction between both terminals of the capacitor C1 and turning on the switching element Q61. Thereafter, the light source module 2 can be turned on by starting the driving of the H-bridge circuit 14.

  As a more preferable form of the lighting device 210, the control circuit 122 keeps the switching element Q60 on until a predetermined “mask period” elapses after the voltage detected by the voltage detection circuit 16 becomes equal to or higher than the threshold value. Further, the switching element Q61 may be kept off. By providing the mask period, it is possible to suppress the attachment / detachment detection of the light source module 2 in a state where the discharge of the capacitor C1 is insufficient. In order to accurately detect the reconnection of the light source module 2, it is preferable that the mask period has such a length that the voltage of the capacitor C <b> 1 is not more than the voltage Vx <b> 1 supplied by the detection power supply circuit 19. Specifically, when the voltage of the capacitor C1 is Vc, it is preferably set to a time until Vc = Vx1 after the start of discharging of the capacitor C1, or set to a longer time than that of the capacitor C1. More preferably, the discharge is performed more sufficiently. More preferably, the control circuit 122 can change the length of the mask period, for example, by being programmable.

  FIG. 4 is a circuit diagram of a lighting device 310 and a lighting fixture 1 including the lighting device 310 according to a modification of the embodiment of the present invention. The lighting device 310 is obtained by replacing the detection power supply circuit 19 with a detection power supply circuit 119 in the lighting device 210 of FIG.

DESCRIPTION OF SYMBOLS 1 Lighting fixture, 2 Light source module, 2a LED element, 4 AC power supply, 6 Rectifier circuit, 10, 110, 210, 310 Lighting device, 10a Positive output terminal, 10b Negative output terminal, 14H bridge circuit, 16 Voltage detection circuit, 18 discharge circuit, 19, 119 detection power supply circuit, 20 driver circuit, 22 microcomputer, 30 signal generation circuit

Claims (10)

A first output terminal and a second output terminal;
A rectifier circuit connected to an AC power source and rectifying the AC voltage;
An H-bridge circuit connected to the rectifier circuit;
A capacitor provided on the output side of the H-bridge circuit, having one end electrically connected to the first output terminal and the other end electrically connected to the second output terminal;
A voltage detection circuit for detecting a voltage between the first and second output terminals;
A rectifying element provided in a direction in which current flows in one direction from the one end of the capacitor toward the first output terminal;
A discharge circuit capable of conducting the one end and the other end of the capacitor so as to discharge the capacitor;
A power supply circuit for applying a voltage between the first and second output terminals;
With
A lighting device that discharges the capacitor by the discharge circuit and applies a voltage between the first and second output terminals by the power supply circuit when the voltage detected by the voltage detection circuit is equal to or higher than a threshold value. A current detection resistor having one end connected to the second output terminal and the other end grounded;
A switch that is connected in series with the current detection resistor and is capable of switching whether or not the second output terminal is connected to a ground potential via the current detection resistor;
The lighting device according to claim 1.   The lighting device according to claim 2, wherein when the voltage detected by the voltage detection circuit is equal to or higher than a threshold value, the discharge circuit discharges the capacitor and turns off the switch.   After the voltage detected by the voltage detection circuit becomes equal to or higher than a threshold value, the one end and the other end of the capacitor are made conductive and the switch is kept off until the mask period elapses. Item 4. The lighting device according to Item 2 or 3. A control circuit for controlling the discharge circuit and outputting a control signal for the switch according to the mask period;
The lighting device according to claim 4, wherein the control circuit can change the mask period. A signal generation circuit that generates an attachment / detachment signal that switches according to attachment / detachment of a load to the first and second output terminals based on a voltage of the second output terminal;
6. The method according to any one of claims 2 to 5, wherein when the detachment signal indicates that the load is connected to the first and second output terminals, the conduction of the discharge circuit is canceled and the switch is turned on. The lighting device described.   The lighting device according to claim 1, wherein the power supply circuit includes a Zener diode having a cathode connected to a DC voltage source and an anode connected to the first output terminal. The power supply circuit is
A resistor having one end receiving the output voltage of the rectifier circuit and the other end connected to the first output terminal;
A Zener diode whose cathode is connected to a circuit connecting the rectifier circuit and the first output terminal and whose anode is grounded;
The lighting device according to claim 1, comprising: A light source including at least one light emitting element is connected to the first and second output terminals,
The lighting device according to claim 1, wherein a voltage applied by the power supply circuit is smaller than a forward voltage of the light emitting element. A light source comprising a light emitting element and a resistor connected in parallel to the light emitting element;
A lighting device comprising first and second output terminals connected to the light source and lighting the light emitting element;
With
The lighting device is
A rectifier circuit connected to an AC power source and rectifying the AC voltage;
An H-bridge circuit connected to the rectifier circuit;
A capacitor provided on the output side of the H-bridge circuit, having one end electrically connected to the first output terminal and the other end electrically connected to the second output terminal;
A voltage detection circuit for detecting a voltage between the first and second output terminals;
A rectifying element provided in a direction in which a current flows in one direction from one end of the capacitor toward the first output terminal;
A discharge circuit capable of conducting both ends of the capacitor so as to discharge the capacitor;
A power supply circuit for applying a voltage between the first and second output terminals;
With
When the voltage detected by the voltage detection circuit exceeds a threshold value, the capacitor is discharged by the discharge circuit, and a voltage is applied between the first and second output terminals by the power supply circuit.

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