JP2011113764A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and a lighting fixture in which a change in light output of a discharge lamp at the time of switching an energization state to a preheating circuit does not give a user a sense of incongruity.
A lighting circuit that outputs an AC voltage between filament electrodes of a hot-cathode discharge lamp, a preheating circuit that energizes both ends of each filament electrode of the discharge lamp, and preheating that turns on / off power feeding to the preheating circuit And a switch Q3. When the output state of power from the lighting circuit to the discharge lamp is switched from the low output state to the high output state, a transient operation of gradually increasing the dimming ratio (output power to the discharge lamp) over a predetermined time Td. The preheating switch Q3 is turned off after the end of the transient operation. Compared with the case where the preheating switch Q3 is turned off simultaneously with the start of the transient operation, the change in the light output before and after the preheating switch Q3 is turned off becomes smaller as a ratio.
[Selection] Figure 1

Description

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

  Conventionally, as a discharge lamp lighting device for lighting a hot cathode type discharge lamp having a filament electrode, it is connected to a lighting circuit for lighting the discharge lamp by outputting an AC voltage between the filament electrodes of the discharge lamp, and the lighting circuit. There is provided a preheating circuit that energizes between both ends of each filament electrode of the discharge lamp and a preheating switch that turns on and off the power supply from the lighting circuit to the preheating circuit (see, for example, Patent Document 1). In other words, when the preheating of each filament electrode of the discharge lamp is necessary, such as when starting the lighting of the discharge lamp, the preheating switch is turned on to preheat each filament electrode by the preheating circuit. Since the preheating switch is turned off, useless power consumption and electrical stress in each filament electrode and preheating circuit of the discharge lamp can be avoided.

  An example of this type of discharge lamp lighting device is shown in FIG. The discharge lamp lighting device of FIG. 5 is for lighting a hot cathode type discharge lamp La having two filament electrodes, and is a diode bridge DB for full-wave rectification of AC power input from an external AC power supply AC. An across-the-line capacitor Cx connected between the DC output terminals of the diode bridge DB, a DC power supply circuit 1 for converting the DC output (pulsating current output) of the diode bridge DB into DC power of a predetermined voltage, and a DC power supply circuit A switching unit 21 composed of a series circuit of two switching elements Q1, Q2 and a current detection resistor R1 connected between the output terminals of the first output terminal, and a low voltage side output terminal of the switching unit 21; A resonance unit 22 that is connected to each filament electrode of the discharge lamp La and constitutes a resonance circuit together with the discharge lamp La, and a pair of filament electrodes of the discharge lamp La A preheating circuit 3 for supplying a preheating current, a preheating switch Q3 for turning on / off the energization of the preheating circuit 3, and a control circuit 4 for controlling the DC power supply circuit 1, the switching unit 21 and the preheating switch Q3, respectively. Prepare. The switching unit 21 and the resonance unit 22 constitute a lighting circuit 2 composed of a known half-bridge inverter circuit as a whole. The switching elements Q1, Q2 and the preheating switch Q3 of the switching unit 21 are each composed of, for example, NMOS.

  More specifically, the DC power supply circuit 1 includes an inductor L0 having one end connected to a DC output end on the high voltage side of the diode bridge DB, a diode D0 having an anode connected to the other end of the inductor L0, and a diode D0 having one end. Is connected in parallel to a capacitor C0 connected to the cathode of the DC power supply and connected to the DC output terminal on the low voltage side of the DC power supply circuit, and a series circuit of a diode D0 and a capacitor C0 made of, for example, NMOS. This is a well-known boost converter (step-up chopper circuit) that includes a switching element Q0 that is periodically turned on and off by the circuit 4 and that has both ends of the capacitor C0 as output ends. The control circuit 4 monitors the output voltage of the DC power supply circuit 1 and changes the on-duty of the switching element Q0 at any time so as to keep the output voltage of the DC power supply circuit 1 constant (for example, 300 V).

  The resonance unit 22 includes an inductor L1 having one end connected between the switching elements Q1 and Q2 of the switching unit 21, and one end connected to the other end of the inductor L1 and the other end being an output on the low voltage side of the DC power supply circuit 1. A parallel capacitor Cp connected to one end, a series capacitor Cs having one end connected to a connection point between the inductor L1 and the parallel capacitor Cp and the other end connected to one end of one filament electrode of the discharge lamp La; One end of a series winding side is connected to one end of the other filament electrode of the electric lamp La, and an autotransformer AT is connected to the shunt winding between both ends of the parallel capacitor Cp.

  The preheating circuit 3 has one end connected to the connection point of the switching elements Q1 and Q2 of the switching unit 21 via a capacitor, and the other end connected to the output terminal on the low voltage side of the DC power supply circuit 1 via the preheating switch Q3. A transformer TR having a primary winding is provided. Each transformer TR has two secondary windings connected between both ends of one filament electrode of the discharge lamp La as a series circuit with a capacitor. That is, during the period when the preheating switch Q3 is on, the current induced in each secondary winding is supplied to each filament electrode of the discharge lamp La, so that each filament electrode of the discharge lamp La is preheated. Is done.

  When the control circuit 4 alternately turns on and off the switching elements Q1 and Q2 of the switching unit 21, the resonance frequency of the resonance circuit formed by the resonance unit 22 and the discharge lamp La causes the above-described on / off driving frequency (hereinafter referred to as "operation frequency"). AC voltage is output to the discharge lamp La. The effective value of the output voltage to the discharge lamp La becomes higher as the operation frequency is closer to the resonance frequency of the resonance circuit.

  Further, the control circuit 4 is supplied with an on / off control voltage Vp and an output control voltage Vd from the outside, and the control circuit 4 detects each switching element of the switching unit 21 during the period when the on / off control voltage Vp is at L level. The output of electric power to the discharge lamp La is stopped by maintaining Q1 and Q2 in the off state, respectively, and the on / off drive of the switching elements Q1 and Q2 of the switching unit 21 is performed only during the period when the on / off control voltage Vp is at the H level. By doing so, electric power is output from the resonance part 22 to the discharge lamp La. Further, immediately after the on / off control voltage Vp is switched from the L level to the H level, the control circuit 4 performs a starting operation for driving the switching elements Q1 and Q2 of the switching unit 21 so as to start the discharge lamp La. After performing, the steady operation which maintains lighting of the discharge lamp La is started. The starting operation is performed, for example, with a current of about 700 mA from the preheating circuit 3 while maintaining the operating frequency sufficiently high (for example, 95 kHz) with respect to the above-described resonance frequency so that discharge is not started in the discharge lamp La. After performing the operation of preheating each filament electrode of La for a predetermined time, the operating frequency is sufficiently close to the above resonance frequency (for example, 75 kHz) to the extent that discharge is started in the discharge lamp La. In La, discharge and lighting are started.

  Although the content of the starting operation does not depend on the output control voltage Vd, in the steady operation, the control circuit 4 outputs the output power (active power) to the discharge lamp La estimated from the voltage across the current detection resistor R1. ) Is set to a target value corresponding to the output control voltage Vd. During steady operation, the target value when the output control voltage Vd is at the H level is set higher than the target value when the output control voltage Vd is at the L level.

  Further, the control circuit 4 turns on the preheating switch Q3 during the starting operation for starting the discharge lamp La, and keeps the temperature of each filament electrode of the discharge lamp La sufficiently high. An operation state in which the output power to the discharge lamp La is reduced to such an extent that a current needs to flow from the preheating circuit 3 to each filament electrode of the discharge lamp La to maintain the lighting of La (hereinafter referred to as “low output state”). It is also turned on during the operation in step 2). The operation in the low output state is performed during a period in which the output control voltage Vd is at the L level during the steady operation, and the operating frequency during the operation in the low output state is, for example, 80 kHz.

  Conversely, in an operating state where the output power to the discharge lamp La is sufficiently increased to such an extent that it is not necessary to pass the current as described above (hereinafter referred to as a “high output state”), the preheating switch Q3 is If the preheating switch Q3 is turned on without being turned on, useless power consumption occurs in each filament electrode of the preheating circuit 3 and the discharge lamp La, and each filament electrode of the discharge lamp La Unnecessarily applying electrical stress will adversely affect the life of the discharge lamp La. Therefore, the control circuit 4 stops the power supply to the preheating circuit 3 by turning off the preheating switch Q3 during the operation in the high output state as described above, and wasteful power consumption as described above is reduced. Prevent electrical stress. The operation in the high output state is performed during a period in which the output control voltage Vd is at the H level during the steady operation, and the operation frequency during the operation in the high output state is, for example, 55 kHz.

JP 2005-19142 A

  Here, at the time of switching between the low output state and the high output state, as shown in FIGS. 6 and 7, a predetermined time (for example, 2.5 seconds) is taken over the rated power of the discharge lamp La (for example, 2.5 seconds). For example, consider a transient operation in which the ratio of output power to the discharge lamp La (hereinafter referred to as “light control ratio”) with respect to 100 W is gradually changed. The luminous flux of the discharge lamp La is almost directly proportional to the dimming ratio. 6 and 7, the dimming ratio in the low output state is 10%, the dimming ratio in the high output state is 100%, and FIG. 6 is a switch from the high output state to the low output state. FIG. 7 shows switching from the low output state to the high output state. 6 and 7, the preheating switch Q3 is switched on and off simultaneously with the start of the transient operation.

  By the way, when the preheating switch Q3 is switched on / off, the power consumption in the preheating circuit 3 is also switched, so that the output power to the discharge lamp La also changes. For example, in the example of FIG. 6, the dimming ratio decreases from 100% to 98% as the preheating switch Q3 is turned on, and in the example of FIG. 7, the dimming ratio starts from 10% as the preheating switch Q3 is turned off. It has risen to 15%.

  The width of the dimming ratio change (that is, the change in the light output of the discharge lamp La) accompanying the on / off switching of the preheating switch Q3 as described above is 2% as a ratio to the numerical value before the change in the example of FIG. 7 is relatively inconspicuous, but in the example of FIG. 7, the ratio to the numerical value before the change is as large as 50%, so that it is relatively conspicuous and may give the user a sense of incongruity.

  The present invention has been made in view of the above reasons, and its purpose is to provide a discharge lamp lighting device in which the change in the light output of the discharge lamp at the time of switching the energization state to the preheating circuit is unlikely to give the user a sense of incongruity. It is to provide a luminaire.

  The invention of claim 1 is a discharge lamp lighting device for lighting a hot cathode type discharge lamp having a filament electrode, and a lighting circuit for lighting the discharge lamp by outputting an AC voltage between the filament electrodes of the discharge lamp; , A preheating circuit for energizing both ends of each filament electrode of the discharge lamp connected to the lighting circuit, a preheating switch for turning on / off power supply from the lighting circuit to the preheating circuit, and a control for controlling the lighting circuit and the preheating switch, respectively. The control circuit has a high output power from the lighting circuit to the discharge lamp to the extent that the discharge lamp can be maintained even when the preheating switch is turned off in accordance with an output control signal input from the outside. The control state is switched between the output state and the low output state where the output power from the lighting circuit to the discharge lamp is less than in the high output state and the preheat switch needs to be kept on. When switching from a low output state to a high output state, a transient operation is performed to gradually increase the output power from the lighting circuit to the discharge lamp, and a predetermined hold time elapses from the start of the transient operation. In this case, the preheating switch is turned off.

  According to the present invention, when switching from the low output state to the high output state, the light output of the discharge lamp before and after the preheating switch is turned off is compared with the case where the preheating switch is turned off simultaneously with the start of the transient operation. Since the change is small as a ratio, it is difficult for the user to feel uncomfortable.

  According to a second aspect of the present invention, in the first aspect of the invention, when the control circuit switches from the high output state to the low output state, the control circuit performs a transient operation that gradually decreases the output power to the discharge lamp, When switching to the output state, the time until the preheating switch is switched on / off after the start of the transient operation is longer than when switching from the high output state to the low output state.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the duration of the transient operation is 2 seconds or more, and the control circuit outputs the preheating switch OFF control from the lighting circuit to the discharge lamp. It is characterized in that it is performed when the power is 90% or more of the output power in the high output state.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the control circuit maintains the preheating switch in an on state and starts the lighting circuit when starting the lighting of the discharge lamp in response to an input from the outside. After starting the discharge lamp by a start operation that performs control that does not depend on the output control signal, the control is to start the discharge lamp, and then the high output state and the low output according to the output control signal. The preheating switch is not controlled to be turned off at least until the start operation is completed.

  The invention according to claim 5 is the invention according to claim 4, further comprising a no-load determination circuit for determining whether or not the discharge lamp is connected to the lighting circuit, and the control circuit is configured so that the discharge lamp is not connected to the lighting circuit. During the period when the determination is made by the no-load determination circuit, the output of power from the lighting circuit to the discharge lamp is stopped, and the determination result of the no-load determination circuit indicates that the discharge lamp is not connected to the lighting circuit. When the determination circuit switches to the determination that the discharge lamp is connected to the lighting circuit, the starting operation is started. The control circuit is started by switching the determination result of the no-load determination circuit. Even if the operation is started, the preheating switch is not controlled to be turned off at least until the start operation is completed.

  Invention of Claim 6 is the discharge lamp lighting device of any one of Claims 1-5, and the fixture main body holding each of the discharge lamp connected to the discharge lamp lighting device, and the discharge lamp lighting device, It is characterized by providing.

  According to the invention of claim 1, when the control circuit switches from the low output state to the high output state, the predetermined hold time from the start of the transient operation that gradually increases the output power from the lighting circuit to the discharge lamp. Since the preheating switch is controlled to be turned off when the time elapses, when switching from the low output state to the high output state, the preheating switch is controlled before and after the preheating switch is turned off compared to when the preheating switch is turned off simultaneously with the start of the transient operation. Since the change in the light output of the discharge lamp becomes small as a ratio, it is difficult for the user to feel uncomfortable.

It is explanatory drawing which shows the time change of the output control voltage Vd at the time of transfer to the high output state from the low output state in the embodiment of this invention, the ON / OFF state of the preheating switch Q3, and the light control ratio. It is explanatory drawing which shows the time change of the output control voltage Vd, the on-off state of the preheating switch Q3, and the light control ratio about the case where the output control voltage Vd is L level at the time of starting in the same as the above. It is explanatory drawing which shows the time change of the output control voltage Vd, the on-off state of the preheating switch Q3, and the light control ratio about the case where the output control voltage Vd is H level at the time of starting in the same as the above. It is a disassembled perspective view which shows an example of the lighting fixture using the same as the above. It is a circuit block diagram which shows an example of a discharge lamp lighting device. It is explanatory drawing which shows the time change of the output control voltage Vd at the time of transfer from a high output state to a low output state, the on-off state of the preheating switch Q3, and a dimming ratio in the same as the above. It is explanatory drawing which shows the time change of the output control voltage Vd at the time of transfer from a low output state to a high output state, the on-off state of the preheating switch Q3, and the light control ratio in a prior art example.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  The basic configuration of this embodiment is the same as that of the conventional example described with reference to FIG.

  In the present embodiment, the preheat switch Q3 is turned on simultaneously with the start of the transient operation when switching from the high output state to the low output state, as in FIG. As shown in FIG. 1, the preheating switch Q3 is turned off after the end of the transient operation. Specifically, for example, when the duration Td of the transient operation started when the output control voltage Vd changes from the L level to the H level is 2.5 seconds, the output control voltage Vd changes from the L level to the H level. The time Tqd until the preheating switch Q3 is turned off after that is 3 seconds, that is, the preheating switch Q3 is turned off when 0.5 second has elapsed after the end of the transient operation.

  According to the above configuration, the change in the light output of the discharge lamp La before and after the preheating switch Q3 is turned off becomes smaller as a ratio compared to the case where the preheating switch Q3 is turned off simultaneously with the start of the transient operation. It is hard to give a strange feeling to the person.

  Note that the timing of the off control of the preheating switch Q3 is not limited to the above as long as it is after the start of the transient operation. However, the off control of the preheating switch Q3 has a dimming ratio of 90% or more (that is, to the discharge lamp La). It is desirable that the output power be performed at a timing such that the output power is 90% or more of the output power in the high output state.

  By the way, in this embodiment, the starting operation PP started by the control circuit 4 when the on / off control voltage Vp is switched from the L level to the H level is performed in the discharge lamp La for a predetermined time as shown in FIGS. The pre-heating operation PP1 is started after the pre-heating operation PP1 and the pre-heating operation PP1 in which the operation frequency is maintained so that the voltage between the filament electrodes is lowered to such an extent that the discharge is not started, The discharge start operation PP2 for controlling the operation frequency so as to increase the voltage between the filament electrodes to such an extent that discharge can be started and maintained in the discharge lamp La over a predetermined time, and after the discharge start operation PP2 for a predetermined time. And a steady transition operation PP3 that makes the dimming ratio higher than 100%. The duration of the preceding preheating operation PP1 and the duration of the discharge start operation PP2 are each 1 second, for example, and the duration of the steady transition operation PP3 is 0.5 seconds, for example. The steady operation for controlling the operation frequency based on the output control voltage Vd is started at the end of the start operation PP composed of the series of operations PP1 to PP3.

  As shown in FIG. 2, when the output control voltage Vd is at the L level at the end of the start operation PP, the preheating switch Q3 is kept on even after the end of the start operation PP, and after the end of the start operation PP, The light is continuously and gradually dimmed from the dimming ratio (98% in the figure) when the preheating switch Q3 is on and the operating frequency is equivalent to the high output state to 10% in the figure. Output is reduced.

  On the other hand, as shown in FIG. 3, when the output control voltage Vd is at the H level at the end of the start operation PP, the preheating switch Q3 is turned off when, for example, 0.5 seconds elapses after the end of the start operation PP. Done in That is, in the above case, the time Tqp from when the start operation PP is started until the preheating switch Q3 is turned off is 3 seconds longer than the duration (2.5 seconds) of the start operation PP. Note that the timing of turning off the preheating switch Q3 is not limited to the above, and may be any time after the timing of ending the starting operation PP.

  A no-load determination circuit (not shown) for determining whether or not the discharge lamp La is connected to the lighting circuit 2 may be added. That is, the control circuit 4 stops the output of power from the lighting circuit 2 to the discharge lamp La during the period when the determination that the discharge lamp La is not connected to the lighting circuit 2 is made by the no-load determination circuit. In addition, the determination result of the no-load determination circuit switches from the determination that the discharge lamp La is not connected to the lighting circuit 2 to the determination that the discharge lamp La is connected to the lighting circuit 2. The control circuit 4 starts the starting operation PP. In this case, even the starting operation PP that is started by switching the determination result of the no-load determination circuit as described above can be performed in the same manner as in FIGS. Since the above-described no-load determination circuit can be realized by a well-known technique, illustration and detailed description thereof are omitted.

  The various discharge lamp lighting devices can be used in a lighting fixture 5 as shown in FIG. The lighting fixture 5 of FIG. 4 stores and holds the circuit components of the diode bridge DB, the DC power supply circuit 1, the lighting circuit 2, the preheating circuit 3, and the control circuit 4, and is connected to the lighting circuit 2 and the preheating circuit 3. An instrument body 51 that holds the ring-shaped discharge lamp La and is fixed to a mounting surface (not shown) such as a ceiling surface, and a space in which the discharge lamp La is made of a light-transmitting material is stored. It comprises a shade 52 that is detachably coupled to the instrument body 51 in the form of being configured with the body 51. Further, in the appliance main body 51, an external block 53 in which the receiving device and the nightlight device are integrated, and a terminal pin provided on the discharge lamp La and electrically connected to the filament electrode are indicated by a dashed arrow A1. Thus, the sockets 54 to be inserted and connected are respectively held. In the external block 53 described above, the receiving device receives a wireless signal transmitted from a remote control device (not shown) using infrared light as a medium, and an on / off control voltage Vp and output control according to the received wireless signal. The voltage Vd is input to the control circuit 4, and the nightlight device includes a nightlight composed of, for example, LEDs and a nightlight lighting circuit that is controlled by the control circuit 4 and supplies power for lighting to the nightlight. Electrical connection between the AC power supply AC and the diode bridge DB is achieved by using a connector 55 connected as shown by an arrow A2. Since the lighting fixture 5 as described above can be realized by a known technique, detailed description thereof is omitted.

2 lighting circuit 3 preheating circuit 4 control circuit 5 lighting fixture 51 fixture body La discharge lamp Vd output control voltage (output control signal in claims)

Claims (6)

A discharge lamp lighting device for lighting a hot cathode type discharge lamp having a filament electrode,
A lighting circuit for lighting the discharge lamp by outputting an alternating voltage between the filament electrodes of the discharge lamp;
A preheating circuit for energizing both ends of each filament electrode of the discharge lamp connected to the lighting circuit;
A preheating switch for turning on / off the power supply from the lighting circuit to the preheating circuit;
A control circuit for controlling the lighting circuit and the preheating switch,
In accordance with an output control signal input from the outside, the control circuit has a high output state in which the output power from the lighting circuit to the discharge lamp is high enough to maintain the discharge lamp even when the preheating switch is turned off, Switch the control state between the low output state where the output power from the lighting circuit to the discharge lamp is less than the output state and the preheat switch needs to be kept on, from the low output state to the high output state When switching to, a transient operation that gradually increases the output power from the lighting circuit to the discharge lamp is performed, and the preheating switch is turned off when a predetermined holding time has elapsed from the start of the transient operation. Discharge lamp lighting device. When switching from the high output state to the low output state, the control circuit performs a transient operation that gradually reduces the output power to the discharge lamp,
When switching from the low output state to the high output state, the time until the preheating switch is switched on / off after the start of the transient operation is longer than when switching from the high output state to the low output state. The discharge lamp lighting device according to 1. The duration of the transient operation is more than 2 seconds,
3. The control circuit according to claim 1, wherein the control circuit performs off-control of the preheating switch when the output power from the lighting circuit to the discharge lamp is 90% or more of the output power in the high output state. Discharge lamp lighting device.   The control circuit is a control for starting the lighting of the discharge lamp with respect to the lighting circuit while maintaining the preheating switch on when starting the lighting of the discharge lamp in response to an input from the outside, and an output control signal After starting the lighting of the discharge lamp by the start operation that performs the control independent of the control, the state is shifted to either the high output state or the low output state according to the output control signal, and at least the start operation ends. The discharge lamp lighting device according to any one of claims 1 to 3, wherein the preheating switch is not controlled to be off. Provided with a no-load determination circuit that determines whether or not the discharge lamp is connected to the lighting circuit,
The control circuit stops the output of power from the lighting circuit to the discharge lamp during the period when the determination that the discharge lamp is not connected to the lighting circuit is performed by the no-load determination circuit, and the no-load determination circuit When the determination result is changed from the determination that the discharge lamp is not connected to the lighting circuit to the determination that the discharge lamp is connected to the lighting circuit, the starting operation is started. And
The control circuit according to claim 4, wherein the control circuit does not control the preheating switch to be turned off at least until the start operation is completed even when the start operation is started by switching of the determination result of the no-load determination circuit. Electric light lighting device.   A discharge lamp lighting device according to any one of claims 1 to 5, and a fixture main body that holds the discharge lamp and the discharge lamp lighting device connected to the discharge lamp lighting device, respectively. lighting equipment.

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