JP4956147B2 - Discharge lamp lighting device and lighting fixture - Google Patents

Description

  The present invention relates to a discharge lamp lighting device capable of collectively lighting a plurality of discharge lamps, and a lighting fixture equipped with the discharge lamp lighting device and a plurality of discharge lamps.

  FIG. 9 shows a schematic configuration of a conventional discharge lamp lighting device. This discharge lamp lighting device controls lighting of two discharge lamps, and is disclosed in, for example, Japanese Patent Laid-Open No. 10-326682 (FIG. 2). When the switch SW1 is turned on, the AC power source AC is connected to the rectifier circuit unit 1 and the AC voltage is rectified and then input to the DC power source unit 2 to output a predetermined DC voltage Vdc. The DC power supply unit 2 has a boost chopper configuration, for example, and is controlled by the control means 3 so that the predetermined DC voltage Vdc becomes a substantially constant value.

  The output of the DC power supply unit 2 is connected to an inverter unit 4 for converting a DC voltage into a high frequency, and the inverter unit 4 is a half bridge type including a series circuit of a pair of switch elements Q11 and Q12 made of a power MOSFET. The oscillation frequency and on / off time of the switch elements Q11 and Q12 of the inverter unit 4 are controlled by the inverter control unit 5, and the switch elements Q11 and Q12 are alternately turned on and off by the drive signal output from the inverter control unit 5. By this operation, a high-frequency rectangular wave voltage is generated at the output of the inverter unit 4 (a connection point between the source terminal of the switch element Q11 and the drain terminal of the switch element Q12).

  The output of the inverter unit 4 is connected to a resonance circuit unit 6 including an inductor L1A and a capacitor C2A via a DC cut capacitor C1A, and further, an inductor L1B and a capacitor C2B are connected in series via a DC cut capacitor C1B. A resonant circuit section 7 composed of a circuit is connected in parallel. Discharge lamps LA and LB are connected in parallel to capacitors C2A and C2B via filament portion F, respectively. Due to the high frequency operation of the inverter unit 4, resonance voltages are generated at both ends of the capacitors C2A and C2B of the resonance circuit units 6 and 7, and the discharge lamps LA and LB are started and lit by this resonance voltage. In this configuration, a predetermined discharge lamp output is obtained by modulating the oscillation frequency to a predetermined value.

  The feature of this conventional configuration is that a plurality of resonance circuit sections 6 and 7 are connected to the inverter section 4 in parallel. The advantage that a plurality of resonance circuit units 6 and 7 are connected to the inverter unit 4 in parallel is that it is not necessary to provide a plurality of inverter units 4, so that the number of components and the cost of components can be reduced.

Although this conventional example is composed of two discharge lamps LA and LB, the advantage is further exhibited when the number of discharge lamps is larger. In addition, with the configuration of the conventional example, when one discharge lamp is removed, the resonance path is cut off only in the resonance circuit from which the discharge lamp is removed, so that the discharge lamp unconnected side can safely resonate. In addition, there is an advantage that only a normally connected discharge lamp can be started and started normally. In the lamp lighting device, a plurality of parallel connection configurations of resonance circuits as in the conventional example are used.
Japanese Patent Laid-Open No. 10-326682 (FIG. 2)

  However, the following problems occur in this conventional configuration. FIG. 10 shows a circuit configuration in a state where one discharge lamp is disconnected in the conventional configuration, and FIG. 11 shows voltage waveforms of respective parts in the conventional configuration. If the oscillation of the inverter unit 4 continues when the discharge lamp LA is disconnected, the output voltage Vo1 of the inverter unit 4 has the same peak value as the DC voltage Vdc (FIG. 11 (a)) as shown in FIG. It becomes a high-frequency rectangular wave voltage. Note that the oscillation duty ratio of the inverter unit 4 (on / off ratio of the switching elements Q11 and Q12 of the inverter unit 4) is generally set to about 50% in order to increase circuit efficiency. The oscillation duty ratio of the unit 4 is set to about 50%, and accordingly, the waveform of the output voltage Vo1 also becomes a duty ratio of about 50%.

  When the oscillation of the inverter unit 4 continues when one discharge lamp LA is disconnected (the state shown in FIG. 10), the connection point on the high-pressure side of the disconnected discharge lamp LA (the inductor L1A and the discharge lamp in FIG. 9). The output voltage Vo2 generated at the connection point (LA) is an AC rectangular wave voltage from which the DC component of the output voltage Vo1 is removed because the output voltage Vo1 is output via the DC cut capacitor C1A.

  Note that since the actual output voltage Vo2 is superimposed with a resonance voltage (resonance voltage of the inductor L1A and the stray capacitance component C0) due to the influence of the stray capacitance component C0, a high frequency is added to the AC rectangular wave voltage as shown in FIG. This is a waveform in which the ringing component is superimposed. Here, the effective value (Vo2 (RMS)) of the output voltage Vo2 ignoring the ringing component is obtained as follows when the oscillation duty ratio is 50%. The actual effective value component is slightly higher than the following value because the ringing component is superimposed.

Vo2 (RMS) = 0.5 × Vdc (Formula 1)
In the above equation, Vdc is an average value of the output DC voltage of the DC power supply unit 2.

  Thus, as the DC voltage Vdc is higher, the secondary voltage (voltage between the discharge lamp connection point and the circuit ground) generated at the discharge lamp connection point when the discharge lamp is disconnected and the ground voltage (between the discharge lamp connection point and the ground (ground)). When the DC voltage Vdc is set high, there is a high risk of electric shock when the discharge lamp is attached / detached. Therefore, in consideration of safety, the DC voltage Vdc is set higher than necessary. There is a problem that can not be.

  Further, from the viewpoint of safety, when the secondary voltage and the ground voltage are high, an earth mechanism is necessary so that the lighting apparatus can be grounded. In the case of household lighting fixtures, a grounding mechanism must be provided if the hanging type fixture (pendant fixture) exceeds 150V, and the direct attachment type fixture (sealing fixture) exceeds 300V.

  Therefore, in order to eliminate the grounding mechanism of the lighting fixture, the secondary voltage and the ground voltage must be limited to be lower than 150 V in the case of the hanging type appliance and 300 V in the case of the direct installation type appliance. When converted according to (Equation 1), the upper limit value of the DC voltage Vdc is 300 V for the hanging type instrument and 600 V for the direct attachment type instrument. The actual upper limit value is desirably set slightly lower than the above upper limit value in consideration of the voltage increase due to the high frequency ringing component.

  By the way, in recent years, discharge lamps have become longer, and accordingly, the starting voltage required for starting and lighting the discharge lamp is also increasing. The starting voltage is obtained by the resonance action of the resonance circuit unit. However, in order to obtain a higher starting voltage, the resonance action needs to be further strengthened, and the electrical stress of the component tends to increase. In addition, starting voltage variations due to variations in resonant circuit components tend to increase, and there is a possibility that problems such as further increase in electrical stress of components or lighting of the discharge lamp due to insufficient starting voltage may occur.

  In order to avoid this problem, it is sufficient to obtain a predetermined starting voltage without increasing the resonance effect by setting the DC voltage Vdc high. However, if the DC voltage Vdc is increased, the secondary voltage and the ground voltage are also increased. Therefore, the above-described problem occurs.

  In addition, new problems arise in other conventional configurations. FIG. 12 is a circuit diagram of another conventional configuration, and FIG. 13 shows a voltage waveform generated at a high-pressure side connection point on the discharge lamp detachment side in the conventional configuration of FIG.

  The conventional configuration of FIG. 12 is substantially the same as the configuration of FIG. 10, but DC bias paths 8 and 9 are provided in each of the discharge lamps LA and LB, respectively. This configuration is provided, for example, as shown in FIG. 5 of Japanese Patent Laid-Open No. 2002-83699 to detect the extinction of the discharge lamp that occurs when the discharge lamp is abnormal. In the case of FIG. 12, the resistors R1A, R2A, R3A having sufficiently large resistance impedance values compared to the resistance impedance value (generally about several tens to several hundreds Ω) of the discharge lamp in a state where the discharge lamp is normally lit. DC bias paths 8 and 9 are constituted by R1B, R2B, and R3B, and resistors R1A and R1B are provided between the output of the DC power supply unit 2, the DC cut capacitors C1A and C1B of each resonance circuit unit, and the inductors L1A and L1B. Provided between connection points. The resistors R1A and R1B bias the DC voltage Vdc to the discharge lamp connection point. Although inductors L1A and L1B are interposed between the connection points of resistors R1A and R1B and the discharge lamp connection point, they are negligible because they hardly affect the DC component.

  The detection operation when the discharge lamp is abnormal on the discharge lamp LA side will be described. When the discharge lamp LA is normally lit, the resistance impedance value RLA of the discharge lamp LA is very small compared to the resistances R1A, R2A, and R3A, so the DC voltage across the resistance R3A (the DC voltage Vdc and the resistances R1A and R2A) , R3A, and RLA (divided voltage generated from RLA) is approximately 0V. Note that the capacitor C7A connected to both ends of the resistor R3A is provided for AC voltage removal. As a result, only the DC voltage Vdc and the divided voltages of the resistors R1A, R2A, R3A, and RLA are included in the voltage across the resistor R3A. appear. The voltage across the resistor R3A is input to the inverter control unit 5, and when this voltage is at a low voltage level, it is determined that the discharge lamp is in a normal state, and normal operation is continued.

  When the discharge lamp LA is extinguished due to the abnormality of the discharge lamp LA, the resistance impedance value RLA of the discharge lamp LA becomes almost infinite, so the DC voltage across the resistor R3A is generated from the DC voltage Vdc and the resistors R1A, R2A, and R3A. A divided voltage having a high voltage level is generated and input to the inverter control unit 5. When this voltage is at a high voltage level, it is determined that the discharge lamp is in an abnormal state, and a protective operation such as stopping oscillation is performed.

  Similarly, when the discharge lamp LA is removed, the DC voltage across the resistor R3A generates the DC voltage Vdc and the divided voltage of the resistors R1A, R2A, and R3A. In this case, the control to shift to the protection operation is prohibited. In this case, it is possible to guarantee the lighting operation when one discharge lamp is disconnected and the other one is connected (not shown, but by providing switch means for detecting the disconnection of the low-pressure discharge lamp filament and short-circuiting the resistor R3A after detection. Transition control to protection operation can be prohibited).

  In such a configuration in which a DC voltage is biased at the discharge lamp connection point, the secondary voltage and the ground voltage when the discharge lamp is disconnected may be further increased. When the discharge lamp LA is disconnected, the following DC voltage V1 is generated at the discharge lamp connection point.

V1 = A × Vdc (Formula 2)
In the above equation, A is a partial pressure ratio given by the following equation.
A = (R2A + R3A) / (R1A + R2A + R3A)

  In this case, as shown in FIG. 13, the secondary voltage and ground voltage (Vo2) generated when the discharge lamp is removed are voltages obtained by superimposing the DC voltage V1 on the AC rectangular wave voltage of FIG. 11C. Since the combined voltage effective value of the AC rectangular wave voltage and the DC voltage V1 (effective value of the output voltage Vo2) has a relation of the sum of squares of the AC component and the DC component, the effective value (Vo2) of the output voltage Vo2 ignoring the ringing component. (RMS)) is obtained as follows when the oscillation duty ratio is 50%.

Vo2 (RMS) ² = (0.5 × Vdc) ² + V1 ² = (0.5 × Vdc) ² + (A × Vdc) ² (Equation 3)

When (Formula 3) is transformed,
Vo2 (RMS) ² = Vdc ² × (0.5 ² + A ² )

Therefore,
Vo2 (RMS) = √ (0.5 ² + A ² ) (Formula 4)

Therefore, an effective value voltage that is larger by the following magnification (B) than the effective value voltage of only the AC component shown in (Expression 1) is generated.
B = √ (0.5 ² + A ² ) /0.5 (Formula 5)

  For example, in the case of R1A = 900 kΩ, R2A = 600 kΩ, and R3A = 300 kΩ, the voltage dividing ratio A is 0.5, and a large effective value voltage B≈1.4 times larger than the effective value voltage of only the AC component is generated. Therefore, there is a higher risk of electric shock when the discharge lamp is attached / detached. Therefore, in consideration of safety, a grounding mechanism for the lighting fixture is required.

  For example, Japanese Patent Laid-Open No. 7-99089 discloses a conventional example for suppressing electric shock when a discharge lamp is attached / detached. However, in this configuration, means for reducing a secondary voltage and a ground voltage when the discharge lamp is detached is not provided. In addition, since the DC bias path is also present, there is a problem that the secondary voltage and the ground voltage when the discharge lamp is removed are further increased.

  Another conventional example for suppressing the secondary voltage and ground voltage when the discharge lamp is disconnected is, for example, Japanese Patent No. 3505937. This is because the DC voltage Vdc output from the DC power supply unit 2 is 280 V or less. Although setting is disclosed, it becomes a big problem when it corresponds to a long tube discharge lamp, and a bigger problem arises when it is configured to have a DC bias path.

  Further, as other conventional examples for suppressing the secondary voltage and the ground voltage when the discharge lamp is disconnected, there are, for example, Japanese Patent Application Laid-Open Nos. 5-23489 and 2003-45690, which are boosted when the discharge lamp is disconnected. Although it has been disclosed to reduce the output voltage of the chopper, no consideration is given to a configuration in which a DC bias path is present, which causes a significant problem.

  The present invention has been made to solve the above-described problems, and its object is to suppress the occurrence of electric shock by reducing the secondary voltage and ground voltage when the discharge lamp is disconnected. The object of the present invention is to provide an inexpensive discharge lamp lighting device and a lighting fixture using the same because it is excellent in safety and does not require the earthing mechanism of the fixture.

In order to solve the above-described problems, the invention of claim 1 converts the DC power supply unit 2 and the DC output Vdc supplied from the DC power supply unit 2 into a high frequency output as shown in FIG. An inverter unit 4 and a resonant load unit including inductors L1A and L1B and capacitors C2A and C2B are provided . A plurality of the resonant load units are connected in parallel between the output terminals of the inverter unit 4 and are released to the resonant load units, respectively. Means for determining whether or not each of the discharge lamps LA and LB is mounted , means for determining whether or not each of the discharge lamps is lit, and any one of the discharge lamps. When the discharge lamp is not mounted, it is provided with a DC power supply output control means 12 for reducing the output of the DC power supply section 2 within a range in which other normally connected discharge lamps can be continuously lit. DC output supplied Has a DC bias path 8,9 divided voltage Vdc is generated in the discharge lamp connection points for each discharge lamp, the DC bias path 8 and 9 have a partial pressure ratio A to the DC voltage, the discharge lamp connection point When the discharge lamp is mounted and is lit, the discharge lamp is turned on by detecting a decrease in the divided voltage due to the impedance when the discharge lamp is turned on. In the discharge lamp lighting device in which the value of the DC impedance component is set so as to be discriminated , when any of the discharge lamps is not mounted, the DC output Vdc is set to Vdc <150 / √ (A ² +0.5). ² ) It is characterized by being lowered to [V].

In the invention of claim 2, in order to solve the above problem, as shown in FIG. 1, the DC power supply unit 2 and the DC output Vdc supplied from the DC power supply unit 2 are converted into a high frequency output. An inverter unit 4 and a resonant load unit including inductors L1A and L1B and capacitors C2A and C2B are provided . A plurality of the resonant load units are connected in parallel between the output terminals of the inverter unit 4 and are released to the resonant load units, respectively. Means for determining whether or not each of the discharge lamps LA and LB is mounted , means for determining whether or not each of the discharge lamps is lit, and any one of the discharge lamps. When the discharge lamp is not mounted, it is provided with a DC power supply output control means 12 for reducing the output of the DC power supply section 2 within a range in which other normally connected discharge lamps can be continuously lit. DC output supplied Has a DC bias path 8,9 divided voltage Vdc is generated in the discharge lamp connection points for each discharge lamp, the DC bias path 8 and 9 have a partial pressure ratio A to the DC voltage, the discharge lamp connection point When the discharge lamp is mounted and is lit, the discharge lamp is turned on by detecting a decrease in the divided voltage due to the impedance when the discharge lamp is turned on. In the discharge lamp lighting device in which the value of the DC impedance component is set so as to be discriminated , when any of the discharge lamps is not mounted, the DC output Vdc is set to Vdc <300 / √ (A ² +0.5 ² ) It is characterized by being lowered to [V].

  In the invention of claim 3, in the invention of claim 1 or 2, the control means 5 capable of switching the lighting output of the discharge lamp by changing the oscillation frequency of the inverter unit 4, and when the discharge lamp is disconnected, A lighting output switching prohibiting means 15 for prohibiting the switching operation of the lighting output is provided (see FIG. 5).

  The invention of claim 4 is the discharge lamp lighting device according to any one of claims 1 to 3, a main body on which the discharge lamp lighting device is mounted, a plurality of discharge lamps to which electric power is supplied from the discharge lamp lighting device, (Refer to FIG. 7 and FIG. 8).

  According to the first aspect of the present invention, the secondary voltage in a state where the discharge lamp is disconnected even when the DC voltage component is superimposed on the secondary voltage (ground voltage) due to the influence of the DC bias path when the discharge lamp is disconnected. Since the occurrence of electric shock can be suppressed by reducing the ground voltage, it is excellent in safety, the normally connected discharge lamp can be kept lit, and the discharge lamp lighting that eliminates the need for a grounding mechanism for ceiling-suspended appliances There is an effect that a device can be provided.

  According to the second aspect of the present invention, the secondary voltage in a state where the discharge lamp is disconnected even when the DC voltage component is superimposed on the secondary voltage (ground voltage) due to the influence of the DC bias path when the discharge lamp is disconnected. Since the occurrence of electric shock can be suppressed by reducing the ground voltage, it is excellent in safety, the normally connected discharge lamp can be kept lit, and the discharge lamp lighting that eliminates the need for the grounding mechanism of the ceiling-mounted appliance There is an effect that a device can be provided.

  According to the third aspect of the present invention, the secondary voltage in a state where the discharge lamp is disconnected even when the DC voltage component is superimposed on the secondary voltage (ground voltage) due to the influence of the DC bias path when the discharge lamp is disconnected. In addition, it is possible to provide a discharge lamp lighting device that is excellent in safety because it can suppress the occurrence of electric shock by reducing the ground voltage, and that can maintain the lighting of a normally connected discharge lamp even when the lighting output can be switched. There is.

  According to the invention of claim 4, since the generation of electric shock can be suppressed by reducing the secondary voltage and the ground voltage in a state in which the discharge lamp is disconnected, it is excellent in safety, and the normally connected discharge lamp can be kept on. In addition, since an earth mechanism is not required, an inexpensive lighting apparatus can be provided.

(Embodiment 1)
FIG. 1 shows a circuit configuration of the first embodiment, and FIG. 2 shows voltage waveforms of respective parts when the discharge lamp is removed from the first embodiment. In this embodiment, the circuit configuration is substantially the same as that of the conventional example of FIG. 12, but detection units 10 and 11 for detecting whether or not each discharge lamp is mounted are provided, and the detection unit detects the disconnection of the discharge lamp. In this case, DC power supply output control means 12 for reducing the output of the DC power supply unit 2 is provided.

  The detection units 10 and 11 have the same circuit configuration. The detection unit 10 will be described. The output voltage Vdc of the DC power supply unit 2 is divided by resistors R4A, R5A, and R6A, and the connection point between the resistors R5A and R6A is a transistor. The connection point between the resistors R4A and R5A is connected to the base of Q2A to the low-pressure side filament part (the connection point side between the capacitor C2A and the low-pressure side filament part) of the discharge lamp LA, respectively. Capacitor C4A is provided for high-frequency voltage removal, whereby only the DC component voltage is generated at the base of transistor Q2A. Here, the resistances R4A, R5A, and R6A are set to resistance values larger than the resistance value of the filament portion, and when the filament portion is normally connected (that is, when the discharge lamp is mounted), the filament portion Since the combined resistance value of the parallel connection of the series circuit of the resistors R5A and R6A is extremely small, the base voltage of the transistor Q2A is also small, and the transistor Q2A is kept off. When the filament portion is not connected (that is, when the discharge lamp is disconnected), only the voltage is divided by the resistors R4A, R5A, and R6A. Therefore, the base voltage of the transistor Q2A increases and the transistor Q2A maintains the on state.

  The DC power supply output control means 12 includes a transistor Q3 as switch means for switching the output voltage Vdc of the DC power supply unit 2, and a resistor R10 for supplying the base current of the transistor Q3 from the control power supply Vc. The base of the transistor Q3 is connected to the collector of the transistor Q2A. When the transistor Q2A is off, the transistor Q3 is on, and when the transistor Q2A is on, the transistor Q3 is off. The collector of the transistor Q3 is connected to the connection point of the resistors R8 and R9 provided in the control means 3.

  The DC power supply unit 2 has a boost chopper configuration including a switch element Q1, a diode D1, an inductor L2, and a capacitor C3. Since this configuration is a well-known technique, a description of its operation is omitted. On / off control of the switch element Q1 is performed by the control means 3, and the control means 3 is provided with IC1 (for example, product number MC33262 manufactured by ON Semiconductor Co., Ltd.) which is a general-purpose control IC. In this integrated circuit IC1, a signal obtained by dividing the output voltage Vdc by the resistors R7, R8, and R9 is input to the voltage feedback input terminal, and the switch element Q1 is set so that the output voltage Vdc corresponding to the signal level is generated. A drive signal for on / off control is output from the drive output terminal, and so-called feedback operation is performed. That is, the output voltage Vdc can be arbitrarily changed by changing the signal level of the voltage feedback input terminal with respect to the output voltage Vdc, and the signal level with respect to the output voltage Vdc is increased (that is, set by the resistors R7, R8, and R9). The output voltage Vdc can be reduced by increasing the divided voltage ratio.

  The collector of the transistor Q3 provided in the DC power supply output control means 12 is connected to the connection point between the resistors R8 and R9, and the resistor R9 is short-circuited when the transistor Q3 is turned on. When both of the discharge lamps LA and LB are normally mounted, the transistor Q3 is kept on, so that the resistor R9 maintains a short circuit state and the signal level (voltage division ratio) with respect to the output voltage Vdc at the voltage feedback input terminal. ) Becomes smaller, and the output voltage Vdc is set to a larger value (this state is a normal Vdc level). When the discharge lamp is disconnected, the transistor Q3 is turned off, so that the resistor R9 is changed from the short-circuit state to the open state. As a result, the signal level (voltage division ratio) with respect to the output voltage Vdc at the feedback input terminal increases. Vdc becomes smaller.

  When the DC power supply output voltage when the discharge lamp is normally connected is Vdc and the DC power supply output voltage when the discharge lamp is disconnected is Vdc ′, the waveform of each part is as shown in FIG. 2, and Vdc drops to Vdc ′. Therefore, the AC component effective value of the secondary voltage (ground voltage) on the discharge lamp removal side also decreases from Vdc / 2 to Vdc ′ / 2. For example, when Vdc = 260V and Vdc ′ = 200V are set, the secondary voltage (ground voltage) AC component effective value on the discharge lamp removal side decreases from 260/2 = 130V to 200/2 = 100V.

  The switch element Q6 is provided to prohibit switching of the output voltage until the discharge lamp is started and lit. During the discharge lamp start period, the switch element Q6 is turned on, the start period ends, and the lighting mode is entered. After the transition, the switching element Q6 is controlled so as to be turned off so that the operation of decreasing the output voltage does not affect the starting lighting of the discharge lamp.

  Here, the reduced Vdc ′ is such that other normally connected discharge lamps can be kept on, and the secondary voltage (ground voltage) outside the discharge lamp is not more than a predetermined value (150 V or less or 300 V or less). ), It is possible to normally maintain only the normally connected discharge lamp when one discharge lamp is disconnected, and to lower the primary voltage (ground voltage) on the discharge lamp disconnect side. Therefore, it is possible to suppress electric shock that occurs when the discharge lamp is attached / detached, thereby improving safety.

  Further, since the DC bias paths 8 and 9 are provided, the secondary voltage (ground voltage) generated when the discharge lamp is disconnected tends to be higher according to the DC bias, and therefore the DC voltage is generated when the discharge lamp is disconnected. It is necessary to switch to the output voltage Vdc considering the influence of the bias. Referring to FIG. 2, by switching from the output voltage Vdc to Vdc ′, the AC component peak value of the secondary voltage (ground voltage) decreases from Vdc to Vdc ′ and is superimposed on the DC bias path. The value decreases from V1 (DC voltage value obtained by multiplying the DC output voltage Vdc by the DC bias path voltage dividing ratio A) to V2 (DC voltage value obtained by multiplying the DC output voltage Vdc 'by the voltage dividing ratio A of the DC bias path). Therefore, the secondary voltage (ground voltage) can be greatly reduced.

  The case where the discharge lamp LA side comes off will be described in further detail. When the discharge lamp is disconnected, the DC voltage determined by the voltage dividing ratio A (see (Formula 2) of the conventional example) set by the resistors R1A, R2A, and R3A constituting the DC bias path 8 is a secondary voltage (ground voltage). ). The secondary voltage (ground voltage) at this time can be obtained by (Equation 4). Here, the output voltage Vdc of the DC power supply unit 2 for setting the secondary voltage (ground voltage) to 150 V or less is as follows: Asking.

Vo2 (RMS) = Vdc × √ (0.5 ² + A ² ) <150

When this is modified, it becomes as follows.
Vdc <150 / √ (0.5 ² + A ² ) (Formula 6)

  By switching to the output voltage Vdc that satisfies this (Equation 6), it is not necessary to provide a grounding mechanism for the appliance even when the discharge lamp lighting device is incorporated in a household hanging appliance (pendant fence appliance). An inexpensive lighting apparatus can be provided.

  Specifically, when the normal output voltage Vdc is 260 V, and the resistors constituting the DC bias path 8 are R1A = 900 kΩ, R2A = 600 kΩ, R3A = 300 kΩ (the voltage dividing ratio A is 0.5), What is necessary is just to lower | hang the output voltage Vdc at the time of discharge lamp removal to less than the following calculated value.

Vdc <150 / √ (0.5 ² +0.5 ² ) = 212.13 (V)

  Therefore, the output voltage Vdc when the discharge lamp is removed may be set to less than 212V. Since the actual secondary voltage (ground voltage) is superimposed with a ringing component as shown in FIG. 2, it is desirable to set it slightly lower (for example, about 200 V) in consideration of this effect.

  In addition, when the discharge lamp lighting device is used by being incorporated in a household direct attachment type appliance (sealing appliance), if the secondary voltage (ground voltage) is 300 V or less, it is not necessary to provide a ground mechanism in the appliance. In the case of the configuration 1, there is no problem even if the output voltage Vdc is set to about 300 V (the voltage may be 424 V or less).

  However, a problem arises when the configuration of the DC bias path is as shown in FIG. In the case of this configuration, the DC bias path in the state where the discharge lamp is connected is equivalent to the configuration of FIG. 1 (the DC impedance of the inductor and the filament is negligibly small compared to the DC impedance of other resistors). However, when the discharge lamp is disconnected, the DC bias path has no filament path, so only the resistor R1A is effective, and therefore the DC bias path voltage dividing ratio A is approximately 1. In this case, the output voltage Vdc when the discharge lamp is removed may be lowered below the calculated value below.

Vdc <300 / √ (1 ² +0.5 ² ) = 268.33 (V)

  Therefore, the output voltage Vdc when the discharge lamp is disconnected may be set to less than 268V. Since the actual secondary voltage (ground voltage) is superimposed with a ringing component as shown in FIG. 2, it is desirable to set it slightly lower (for example, about 250 V) in consideration of this effect.

  The configuration of the DC bias path is not limited to the configuration shown in FIGS. 1 and 3. For example, a plurality of DC bias paths may exist, and electronic components other than components that block the DC bias path (for example, capacitors) May be interposed in the DC bias path and the main circuit part (circuit constituent parts including a resonance circuit part, an inverter part, a discharge lamp load part, etc.). In short, there is a DC impedance component that exists between the discharge lamp connection point and the output voltage Vdc connection point, and a DC impedance component that exists between the discharge lamp connection point and the circuit ground (or ground (ground)). Any configuration may be used as long as the divided voltage of the output voltage Vdc is generated at the discharge lamp connection point by the aforementioned DC impedance component when the lamp is disconnected.

  In addition, it has means for detecting the disconnection of the discharge lamp, and when the discharge lamp is detected to be disconnected, the output voltage of the DC power supply unit (that is, the input voltage of the inverter unit) is changed to another normally connected discharge lamp. If a configuration for reducing the lighting within the range in which lighting can be maintained is provided, the DC power supply configuration, the inverter configuration, the inverter control circuit configuration, the resonant circuit configuration, the number of resonant circuits, the number of components of the discharge lamp, as shown in this embodiment Needless to say, the present invention is not limited to the number of lamps, discharge lamp detachment detection means configuration, and DC power supply output control means configuration.

  In this way, even when the DC voltage component is superimposed on the secondary voltage (ground voltage) due to the influence of the DC bias path when the discharge lamp is disconnected, the secondary voltage and ground voltage when the discharge lamp is disconnected are reduced. Therefore, it is possible to provide a discharge lamp lighting device that is excellent in safety because the occurrence of electric shock can be suppressed and that can maintain the lighting of a normally connected discharge lamp.

(Embodiment 2)
FIG. 4 shows a schematic circuit configuration of the second embodiment. The present embodiment shows another configuration example relating to the output voltage switching configuration of the DC power supply unit, and other configurations and operation concepts are the same as those of the first embodiment. The DC power supply unit 13 of the present embodiment combines the functions of the rectifier circuit unit 1 and the DC power supply unit 2 shown in FIG. 1 of the first embodiment, and functions as a full-wave rectifier circuit and voltage doubler rectification by the switch means SW2. It can be switched to a function as a circuit. That is, a series circuit of a pair of smoothing capacitors C5 and C6 is connected between the DC output terminals of the rectifier circuit constituted by the diodes D2 to D5, and one end of the AC power supply AC is connected to one AC input terminal of the rectifier circuit. In addition, switch means SW2 is provided as switching means for selectively connecting the other end of the AC power supply AC to the other AC input end of the rectifier circuit and the connection point of the smoothing capacitors C5 and C6.

  When the AC input terminal of the rectifier circuit is selected by the switch means SW2, the DC output voltage of the rectifier circuit is applied to both ends of the series circuit of the smoothing capacitors C5 and C6, so that it functions as a normal full-wave rectifier circuit.

  When the connection point of the smoothing capacitors C5 and C6 is selected by the switch means SW2, a bridge circuit is constituted by one arm (diodes D2 and D3) of the rectifier circuit and the smoothing capacitors C5 and C6, and the AC power supply AC Since the smoothing capacitors C5 and C6 are charged every half cycle of the voltage waveform, the voltage across the series circuit of the smoothing capacitors C5 and C6 is approximately twice the peak voltage of the AC power supply AC.

  Switching of the switch means SW2 is performed via the drive means 14 in accordance with a signal output from the DC power supply output control means 12, and when the discharge lamp is normally connected, the DC power supply unit 13 is used as a voltage doubler rectifier circuit. A function similar to that of the first embodiment can be provided by providing a function and providing the DC power supply unit 13 with a function as a full-wave rectifier circuit when the discharge lamp is disconnected.

(Embodiment 3)
FIG. 5 shows a circuit configuration of the third embodiment, and FIG. 6 shows a current-voltage characteristic graph for explaining the operation of the third embodiment. In this embodiment, the circuit configuration is substantially the same as in FIG. 1 of the first embodiment, but when the dimming signal S is input, the lighting output of the discharge lamp can be switched by changing the oscillation frequency of the inverter unit 4. The control means is provided in the inverter control unit 5 and is different in that a lighting output switching prohibiting means 15 for prohibiting the switching operation of the lighting output is provided when the discharge lamp is disconnected.

  In FIG. 5, control is performed to change the oscillation frequency of the inverter unit 4 so that the discharge lamp output is the all-light output when the dimming signal S is a low signal, and the dimming output when the dimming signal S is a high signal. In this embodiment, the oscillation frequency is changed to 60 kHz at the time of all light output and to 88 kHz at the time of dimming output.

  In the case of the present embodiment, the discharge lamp load is an FCL40 type lamp, the output voltage Vdc of the DC power supply unit 2 in a normal state is 260 V, the inductor of the resonance circuit unit is 0.75 mH, and the capacitor connected in parallel to the discharge lamp is 7 .5 nF, the DC cut capacitor is set to 100 nF, and the discharge lamp is lit and maintained at all light output and dimming output at the above-mentioned oscillation frequency. The current-voltage characteristics are shown by curves 16, 17 and 18 in FIG.

  A curve 16 indicated by a broken line is a current-voltage characteristic curve of the FCL40 type lamp, and a curve 17 is a load characteristic curve of the resonance circuit section at the oscillation frequency at the time of all light output (the resistance impedance of the discharge lamp load changes from zero to infinity). And a curve 18 is a load characteristic curve of the resonance circuit section at the oscillation frequency at the time of dimming output. The point where the curve 16 intersects with the curves 17 and 18 is the discharge lamp output at the time of all light and dimming, and the discharge lamp maintains the lighting at the current and voltage indicated by the intersection.

  Here, when the discharge lamp is removed and control is performed to reduce the output voltage Vdc of the DC power supply unit 2 from 260 V to 200 V, the load characteristic curve is the direction in which the discharge lamp output decreases (the direction in which the current and voltage decrease). ), And the load characteristic curves at the time of all light and dimming change from the curve 17 to the curve 19 and from the curve 18 to the curve 20, respectively. In this case, the lighting can be maintained because it has a point that intersects the current-voltage characteristic curve 16 of the FCL40 lamp at all light, but it can be kept on since there is no point at which the curve 16 intersects at the time of dimming. The discharge lamp goes out.

  In order to avoid this state, lighting output switching prohibiting means 15 is provided. The lighting output switching prohibiting means 15 includes transistors Q4 and Q5 and a resistor R11. When the discharge lamp is in a normal state, the transistor Q4 on and the transistor Q5 off are held, and the dimming signal S is not limited. Is input to the inverter control unit 5. When the discharge lamp is disconnected, the transistor Q4 off and the transistor Q5 on are held, and the dimming signal S is held low, thereby prohibiting the switching operation to dimming lighting.

  In this way, even when the DC voltage component is superimposed on the secondary voltage (ground voltage) due to the influence of the DC bias path when the discharge lamp is disconnected, the secondary voltage and ground voltage when the discharge lamp is disconnected are reduced. Thus, it is possible to provide a discharge lamp lighting device that is excellent in safety because it can suppress the occurrence of electric shock and that can maintain the lighting of a normally connected discharge lamp even when the lighting output can be switched.

(Embodiment 4)
FIG. 7 is a schematic side view showing an embodiment of the lighting fixture of the present invention. This embodiment is a ceiling-suspended lighting fixture for home use. In FIG. 7, 21 is a main body chassis, 22 is a translucent cover, 23 is a reflector, 24 is a discharge lamp lighting device, and LA and LB are annular discharge lamps.

  The main body chassis 21 has a circular shallow dish shape, and has means for connecting an AC power source to the power source connecting portion 26 through a power cord 25 from a substantially central portion of the main body chassis 21 and being attached to the ceiling. A mechanism for mounting the translucent cover 22 is provided.

  The reflecting plate 23 and the translucent cover 22 are formed in a shape that reflects light emitted from the discharge lamp to the floor surface. The discharge lamp lighting device 24 has the circuit configuration described in any of Embodiments 1 to 3, and is disposed in a space formed between the main body chassis 21 and the reflection plate 23. The translucent cover 22 is provided so as to cover the main body chassis 21, the discharge lamps LA and LB, the reflection plate 23, and the like.

  In the present embodiment, since the discharge lamp lighting device 24 has the circuit configuration described in the first to third embodiments, it is possible to provide a household ceiling-suspended lighting fixture that exhibits the effects described in the first to third embodiments. Moreover, an inexpensive lighting fixture can be provided by eliminating the need for the earthing mechanism of the fixture.

(Embodiment 5)
FIG. 8 is a schematic side view showing another embodiment of the lighting fixture of the present invention. This embodiment is a ceiling-mounted lighting fixture for home use. In FIG. 8, 21 is a main body chassis, 22 is a translucent cover, 23 is a reflector, 24 is a discharge lamp lighting device, and LA and LB are annular discharge lamps.

  The main body chassis 21 has a circular shallow dish shape, is provided with a power supply connection portion and means for attaching to the ceiling (both not shown), and has a mechanism for mounting the translucent cover 22. The reflection plate 23 is formed as shallow as possible and is shaped to reflect the light emitted from the discharge lamp so that the luminance of the surface of the light-transmitting cover 22 is as uniform as possible. The discharge lamp lighting device 24 has the circuit configuration described in any of Embodiments 1 to 3, and is disposed in a space formed between the main body chassis 21 and the reflection plate 23. The translucent cover 22 is disposed on the lower surface of the main body chassis 21 and surrounds the discharge lamps LA and LB, the reflection plate 23 and the like.

  In the present embodiment, since the discharge lamp lighting device 24 has the circuit configuration described in the first to third embodiments, it is possible to provide a household ceiling-mounted lighting fixture that exhibits the effects described in the first to third embodiments. Therefore, an inexpensive lighting fixture can be provided.

It is a circuit diagram which shows the structure of Embodiment 1 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 1 of this invention. It is a circuit diagram which shows the structure of the modification of Embodiment 1 of this invention. It is a circuit diagram which shows the principal part structure of Embodiment 2 of this invention. It is a circuit diagram which shows the structure of Embodiment 3 of this invention. It is a characteristic view which shows the operation | movement of Embodiment 3 of this invention. It is a schematic side view of the lighting fixture of Embodiment 4 of this invention. It is a schematic side view of the lighting fixture of Embodiment 5 of this invention. FIG. 6 is a circuit diagram of Conventional Example 1. It is a circuit diagram which shows the structure at the time of the discharge lamp removal of the prior art example 1. FIG. It is a wave form diagram which shows the operation | movement at the time of discharge lamp removal of the prior art example 1. FIG. FIG. 10 is a circuit diagram of Conventional Example 2. It is a wave form diagram which shows the operation | movement at the time of discharge lamp removal of the prior art example 2. FIG.

Explanation of symbols

2 DC power source 4 Inverter LA, LB Discharge lamp 8, 9 DC bias path 10, 11 Detector 12 DC power output control means

Claims (4)

A DC power supply unit; an inverter unit that converts a DC output supplied from the DC power supply unit into a high-frequency output; and a resonant load unit including an inductor and a capacitor, and a plurality of the resonant load units are provided between output terminals of the inverter unit. A discharge lamp connected to each of the resonant load sections, a means for determining whether or not each of the discharge lamps is mounted , a means for determining whether or not each of the discharge lamps is lit, and each of the discharge lamps If any of the discharge lamps is not installed, it is equipped with DC power supply output control means that reduces the output of the DC power supply unit within the range in which other normally connected discharge lamps can continue to be lit. has a DC bias path to the divided voltage of the DC output supplied from the DC power supply unit is generated in the discharge lamp connection points for each discharge lamp, the DC bias path to have a partial pressure ratio a to the DC voltage, the discharge lamp Connection point and DC It includes a DC impedance component that exists between the source parts, and when the discharge lamp is mounted and lit, it is possible to determine the lighting of the discharge lamp by detecting a decrease in the divided voltage due to the impedance when the discharge lamp is lit Thus, in the discharge lamp lighting device in which the value of the DC impedance component is set and any one of the discharge lamps is not mounted, the DC output Vdc is set to Vdc <150 / √ (A ² +0.5 ² ). A discharge lamp lighting device characterized by being lowered to [V]. A DC power supply unit; an inverter unit that converts a DC output supplied from the DC power supply unit into a high-frequency output; and a resonant load unit including an inductor and a capacitor, and a plurality of the resonant load units are provided between output terminals of the inverter unit. A discharge lamp connected to each of the resonant load sections, a means for determining whether or not each of the discharge lamps is mounted , a means for determining whether or not each of the discharge lamps is lit, and each of the discharge lamps If any of the discharge lamps is not installed, it is equipped with DC power supply output control means that reduces the output of the DC power supply unit within the range in which other normally connected discharge lamps can continue to be lit. has a DC bias path to the divided voltage of the DC output supplied from the DC power supply unit is generated in the discharge lamp connection points for each discharge lamp, the DC bias path to have a partial pressure ratio a to the DC voltage, the discharge lamp Connection point and DC It includes a DC impedance component that exists between the source parts, and when the discharge lamp is mounted and lit, it is possible to determine the lighting of the discharge lamp by detecting a decrease in the divided voltage due to the impedance when the discharge lamp is lit Thus, in the discharge lamp lighting device in which the value of the DC impedance component is set , if any of the discharge lamps is not mounted, the DC output Vdc is set to Vdc <300 / √ (A ² +0.5 ² ). A discharge lamp lighting device characterized by being lowered to [V]. A control means capable of switching the lighting output of the discharge lamp by changing the oscillation frequency of the inverter unit, and a lighting output switching prohibiting means for prohibiting the switching operation of the lighting output when the discharge lamp is disconnected. The discharge lamp lighting device according to claim 1 or 2. A discharge lamp lighting device according to any one of claims 1 to 3, a main body on which the discharge lamp lighting device is mounted, and a plurality of discharge lamps to which electric power is supplied from the discharge lamp lighting device. Lighting equipment to do.

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