JP2005184940A - Inverter device, discharge lamp lighting device and lighting device - Google Patents

Abstract

【Task】
Provided is an inverter device equipped with a load monitoring / protection function suitable for performing a load monitoring / protection operation using the UVLO function and capable of continuously monitoring even after the protection operation, and a discharge lamp lighting device using the inverter device To do.
[Solution]
The inverter device HFI includes a DC power source DC; an inverter main circuit INV including at least one switching element Q1, Q2, a load circuit LC connected to the output terminal thereof, and a supervisory control means CC2, which is attached by an auxiliary power source SS. When the voltage of the auxiliary power supply SS is the first voltage V1, the operation of the inverter main circuit INV is started, the state of the load circuit LC at a predetermined position is monitored, and a protection operation is performed when necessary. In conjunction with the operation, when the voltage of the auxiliary power supply SS becomes the second voltage V2 lower than the first voltage V1, the voltage of the auxiliary power supply SS is changed to the third voltage lower than the second voltage, and the state continues. And a control circuit CC for monitoring.
[Selection]
FIG.

Description

  The present invention relates to an inverter device, a discharge lamp lighting device and an illumination device using the inverter device.

When the discharge lamp is lit using an inverter, if the discharge lamp is not installed, a high voltage is generated at the output terminal of the inverter, or the inverter operates on the fast phase side of the resonance characteristics, causing stress on the switching element. An increase may occur. Therefore, it is already known that a control circuit is configured to perform a protective operation by providing a detection circuit for detecting the mounting of the discharge lamp and reducing the output of the inverter when non-mounting is detected. (For example, refer to Patent Document 1). Further, in some cases, the inverter output can be stopped when not installed.
JP-A-5-013186

  When performing the above protection operation, it is conceivable to adopt a so-called UVLO (under voltage lock out) function. The UVLO function starts when the voltage reaches the first voltage, and stops when the voltage drops to a second voltage lower than the first voltage. When performing the above-described protection operation using this function, the discharge lamp is mounted by detecting the presence / absence of the filament electrode on the circuit, and when it is not mounted, a control stop signal is output, The control circuit is disabled by short-circuiting the circuit with a switch.

  However, in the latter configuration, it is necessary to separately provide a control power source for monitoring the mounting of the discharge lamp after the control circuit is deactivated. For this reason, there is a problem that the number of circuit parts increases and the cost increases. In addition, when a separate control power source is provided as described above, another control power source is formed from the AC power source or the rectified DC power source via a resistor, resulting in a large power loss consumed by the resistor or the like. Therefore, there is a problem that the conversion efficiency is lowered.

  INDUSTRIAL APPLICABILITY The present invention is suitable for performing a load monitoring / protection operation using the UVLO function, and has an inverter device having a load monitoring / protection function that can be continuously monitored even after the protection operation, and a discharge lamp using the inverter device An object is to provide a lighting device.

    An inverter device according to a first aspect of the invention includes a DC power source; an inverter main circuit including at least one switching element, an input terminal connected to the DC power source, and outputting an AC voltage to the output terminal; an output terminal of the inverter main circuit A load circuit connected to the power supply circuit; and a monitoring control means that is energized by the auxiliary power source to start the operation of the inverter main circuit when the voltage of the auxiliary power source is the first voltage and The monitoring operation is performed when the detection voltage of the state monitoring is a predetermined voltage, and the auxiliary power supply is turned on when the voltage of the auxiliary power supply becomes a second voltage lower than the first voltage in conjunction with the protection operation. And a control circuit for continuously monitoring the state by changing the voltage to a third voltage lower than the second voltage.

  In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

  <Regarding the DC Power Supply> The DC power supply is means for providing input power to the inverter main circuit, and may be any of a battery power supply and a rectified DC power supply. The rectified DC power supply may output any of non-smoothed DC, smoothed DC, and semi-smoothed DC. Alternatively, a DC voltage obtained by stepping up or stepping down the AC voltage may be output. Which of these should be selected may be appropriately determined according to the circuit system of the inverter and the requirements on the load side. When outputting a DC voltage obtained by boosting or stepping down the AC voltage, a switching power supply such as a step-up chopper or a step-down chopper can be used.

  <About Inverter Main Circuit> The inverter main circuit is a means that constitutes a main part of the DC-AC conversion and includes at least one switching element. As the switching element, various semiconductor switching elements such as a transistor can be used. As the transistor, a bipolar transistor, an FET, or the like can be used.

  Further, as the inverter main circuit, various circuit type inverters can be appropriately selected and used. For example, a half-bridge inverter, a one-stone inverter, etc. are suitable when the load is a discharge lamp. A conversion main circuit including a switching element and a drive circuit for driving the switching element are included. The conversion main circuit constitutes a so-called power circuit that performs DC-AC conversion. The drive circuit drives the switching element with current or voltage according to the configuration of the switching element to be used.

  Further, the driving of the switching element of the inverter main circuit may be performed by adopting either the self-excitation method or the separate excitation method. In the case of the self-excited method, the drive circuit forms a drive signal in which an electrical signal corresponding to the AC output generated from the inverter main circuit is feedback-controlled in a negative feedback manner. On the other hand, in the case of the separate excitation method, the drive circuit forms a drive signal based on the oscillation signal generated from the oscillation circuit.

  <Regarding Load Circuit> The load circuit is a circuit means for operating the load circuit by connecting it to the output terminal of the inverter main circuit. Depending on the load connected to the load circuit, the output waveform of the inverter main circuit can be shaped into a sine wave as desired, a high voltage can be applied when starting the load, or the current flowing through the load can be limited. can do. For these purposes, a load resonant circuit can be connected to the load circuit. A load can be connected to either the capacitor or the inductor constituting the load resonance circuit.

  In addition, a DC cut capacitor, that is, a coupling capacitor can be inserted in series in the load circuit in order to cut off the DC connection with the inverter main circuit. Furthermore, it is allowed to connect a circuit means for monitoring a load voltage and a load current for a control circuit described later.

  <Regarding Control Circuit> The control circuit is a means for controlling the inverter device, and in the present invention, includes a monitoring control means and is energized by at least an auxiliary power source. Then, when the voltage of the auxiliary power supply is the first voltage, the inverter main circuit is controlled to start or start its operation.

  The monitoring control means monitors the state of the load circuit at a predetermined position. If there is an abnormality in the load circuit by monitoring, the auxiliary power supply is controlled. The control circuit is configured to perform a protection operation for the inverter main circuit when the voltage of the auxiliary power supply decreases to the second voltage under the control of the monitoring control unit. This protection operation is set in advance so as to stop the operation of the inverter main circuit or restrict the output.

  The supervisory control means is configured to change the voltage of the auxiliary power source to a third voltage lower than the second voltage in conjunction with the protection operation for the inverter main circuit by the control circuit. The monitoring control means is configured to continue monitoring even after the auxiliary power supply voltage is changed to the third voltage, and when the abnormal state of the load circuit does not change from before the protection operation is started, the auxiliary power supply is continued thereafter. The voltage is configured to be maintained at the third voltage. The monitoring control means is configured to restore the auxiliary power supply voltage when the load circuit is in a normal state.

  In the present invention, the UVLO function is provided in the component part of the control circuit that starts the operation at the first voltage and stops the operation when the second voltage lower than the first voltage is reached. Can be adopted.

  The auxiliary power supply may be obtained from a DC power supply for the inverter main circuit, or may be obtained by rectifying the AC power supply separately from the DC power supply in the case of obtaining a DC voltage by rectifying the AC power supply. Further, if necessary, it can be obtained from a power source other than the above. The circuit configuration for changing the voltage of the auxiliary power supply to the third voltage is not particularly limited. For example, the auxiliary power supply voltage can be clamped using a switch circuit that responds when the second voltage is reached. Various known circuits can be used as the clamp circuit in this case. For example, a clamp circuit is connected in parallel to the auxiliary power supply, and a part of a constant voltage element (for example, a plurality of Zener diodes connected in series) for making a constant voltage via a switch when the second voltage is reached is short-circuited This can be realized by switching the clamp voltage to a lower voltage. Alternatively, an auxiliary power supply may be configured using a series stabilized power supply, and the reference voltage may be switched by the switch.

  The auxiliary power supply may monitor the load circuit state and supply power only to the control circuit that controls the inverter main circuit. In addition to this, other control means such as a remote control receiver may be used. Etc. can also be supplied with power. These control means can continuously perform the control operation using the third voltage supplied from the auxiliary power supply as the power supply even after the protection operation for the load circuit.

  Furthermore, the control circuit not only performs the above-described protection operation, but also changes the output of the inverter main circuit according to the operation mode of the load, performs a compensation operation for power supply voltage fluctuations, and changes the output characteristics of the inverter main circuit. Or can be configured to be determined. In order to change the output of the inverter main circuit according to the operation mode of the load, a timer is provided in the control circuit, the operation time for each operation mode is set according to the program prepared in advance by the timer, or the operation of the load The state can be monitored and the operation mode can be determined according to the monitoring result. In order to perform the compensation operation with respect to the power supply voltage, the power supply voltage can be monitored and the output of the inverter main circuit can be controlled so as not to fluctuate according to the power supply voltage fluctuation or less affected by the fluctuation. As output characteristics of the inverter main circuit, desired output characteristics such as constant power characteristics and constant current characteristics can be set.

  <About the operation of the present invention> In the present invention, by having the above configuration, when the voltage of the auxiliary power supply rises to the first voltage, the control circuit starts operation and starts the inverter main circuit. Let Then, the monitoring control means monitors the state of the predetermined position of the load circuit.

  When the monitoring control means detects an abnormality in the load circuit, it controls the auxiliary power supply. As a result, when the auxiliary power supply voltage is lowered to the second voltage, the control circuit causes the inverter main circuit to perform a protection operation. That is, the operation of the inverter main circuit is stopped or the output is reduced. The supervisory control means controls the auxiliary power supply and changes its output voltage to a third voltage lower than the second voltage. As a result, the control circuit is applied with the third voltage after the protection operation. Under such a state, the monitoring control means continues the monitoring of the load circuit and the control for maintaining the auxiliary power supply voltage at the third voltage. Further, as described above, an auxiliary power source can be used in combination as a power source for other control means.

  By performing continuous monitoring as described above, when the abnormal state of the load circuit is subsequently resolved, the monitoring control unit returns the voltage of the auxiliary power source from the third voltage to the original first voltage, so that the control circuit operates. To start. As a result, the inverter main circuit starts operation under the control of the control circuit, and the load circuit operates in a normal state.

    According to a second aspect of the present invention, there is provided a discharge lamp lighting device comprising: the inverter device according to the first aspect; and a discharge lamp provided with a filament electrode and connected to a load circuit of the inverter device. The discharge lamp is connected in parallel to the capacitor of the load circuit; the control circuit includes supervisory control means and is energized by the auxiliary power source so that the voltage of the auxiliary power source is the first When the voltage is a voltage, the operation of the inverter main circuit is started and the mounting state of the discharge lamp of the load circuit is monitored. When the detection voltage of the state monitoring is a predetermined voltage, the auxiliary power supply is controlled. When the second voltage lower than the voltage is reached, the inverter main circuit is controlled to perform the protection operation, and the auxiliary power supply voltage is changed to the third voltage lower than the second voltage. It can monitor the mounting state of the continued discharge lamp; is characterized by.

  The present invention defines a preferred configuration of the discharge lamp lighting device when the discharge lamp is used as a load in the invention of claim 1.

  <Discharge Lamp> The discharge lamp may be any type of discharge lamp, but a low-pressure discharge lamp such as a fluorescent lamp is preferable. Also, when a filament electrode is provided in a low-pressure discharge lamp, a preheating mode is provided in the output characteristics of the inverter main circuit, and in order to preheat the filament electrode during the preheating mode, in parallel with the discharge lamp, that is, a pair of filament electrodes A resonant capacitor can be connected between one power supply terminal and the other power supply terminal or power supply terminal of the same electrode. As a result, the resonant capacitor is connected to the load circuit via at least one non-power supply side terminal of the pair of filament electrodes in the discharge lamp. Then, a series resonance circuit is formed which is connected in series with an inductor (to be described later) of the load circuit and performs appropriate resonance at the time of starting.

  In addition, an electrode heating transformer can be used instead of the above-described configuration in which the filament electrode is heated using a resonance capacitor. The electrode heating transformer can be configured with a secondary winding magnetically coupled to an inductor of a load circuit described later. However, the primary winding of the electrode heating transformer may be directly connected to an AC power source.

  <Regarding the load circuit> The load circuit is connected between the AC output terminals of the inverter main circuit and includes a series circuit portion of an inductor and a resonance capacitor. If desired, a DC cut capacitor, a feedback element, a current detection impedance, etc. Can be inserted in series. The inductor is connected in series with the discharge lamp so that part or all of the inductor acts as a current limiting impedance of the discharge lamp. The resonant capacitor is connected in parallel to the discharge lamp, and forms a series resonant circuit with the inductor when the discharge lamp is started.

  <Regarding Control Circuit> The control circuit includes monitoring control means, and is operated by being energized by an auxiliary power source. Then, when the voltage of the auxiliary power supply rises to the first voltage when the inverter device is turned on, the operation starts to operate the inverter main circuit, and the monitoring control means determines whether the discharge lamp is mounted on the load circuit. Monitor. The specific circuit configuration for monitoring the mounting state of the discharge lamp is not particularly limited, but for example, it can be configured to monitor the potential change of the non-power supply side terminal of the filament electrode in the discharge lamp. If the monitoring is performed on the low side of the discharge lamp, it is safe and the circuit configuration is simplified.

  Further, the control circuit is configured to operate when the monitoring control means detects that the discharge lamp is not mounted, and to control the auxiliary power supply, and the auxiliary power supply voltage decreases during the control. When the auxiliary power supply voltage becomes the second voltage, the control circuit performs a protection operation, and stops the operation of the inverter main circuit according to a preset program, or controls the output voltage to be low. . As a result, protection is performed so that the high voltage at the start is not continuously output from the inverter main circuit.

  The monitoring control means of the control circuit is configured to change the auxiliary power supply voltage to a third voltage lower than the second voltage when it is detected that the discharge lamp is not mounted. The control circuit is configured not to operate the inverter main circuit again even when the third voltage is applied. However, the monitoring control means is configured to continuously monitor by applying the third voltage.

  <About the operation of the present invention> In the present invention, since the above configuration is provided, the operation of the inverter main circuit is started using the change in the voltage of the auxiliary power supply, and the protective operation when the discharge lamp is not installed. Then, it is possible to appropriately switch between subsequent monitoring of the discharge lamp. That is, when the power of the inverter device is turned on, the auxiliary power supply rises, and when the auxiliary power supply voltage becomes the first voltage, the control circuit starts operating. The inverter main circuit is activated by the operation of the control circuit to generate alternating current, which is applied to the load circuit. The monitoring control means of the control circuit monitors whether or not the discharge lamp is mounted on the load circuit, and does not perform a control operation linked to the protection operation when the discharge lamp is mounted.

  On the other hand, since the discharge lamp is connected in parallel to the resonance capacitor of the load circuit, and the inductor and the resonance capacitor form a series circuit portion in the load circuit, moderate series resonance occurs in the series circuit at the start. As a result, a high voltage is generated across the resonant capacitor. Since this high voltage is applied to the discharge lamp connected in parallel to the resonant capacitor, the discharge lamp is easily started and shifted to AC lighting. In addition, at the time of starting, the inverter main circuit is configured so that the control circuit switches the inverter main circuit to the starting mode so as to output an alternating current adjusted so that the discharge lamp can be easily started by resonance of the series circuit portion of the load circuit. can do. Further, when the discharge lamp is turned on, the resonance of the series circuit is automatically suppressed.

  Therefore, the discharge lamp performs high-frequency lighting if the alternating current output from the inverter main circuit is high-frequency. In order to preheat the filament electrode as required before starting the discharge lamp, the control circuit can be configured to switch the inverter main circuit to the preheating mode. In this case, the inverter main circuit outputs an alternating current that is suppressed so that the discharge lamp cannot be started.

  By the way, when the discharge lamp is not attached to the load circuit, the potential at the monitoring position by the monitoring control means of the load circuit becomes the potential at the time when the discharge circuit is not attached, so the auxiliary power supply is controlled by the detected voltage at that time. Therefore, when the auxiliary power supply voltage decreases and becomes the second voltage, the control circuit performs a protection operation. For this reason, the inverter main circuit stops its operation according to a preset program, or continues the operation so that the AC output decreases.

  Further, the control circuit performs the above-described protection operation, and the monitoring control unit changes the auxiliary power supply voltage to a third voltage lower than the second voltage. Then, the monitoring control means continues the monitoring operation. When the discharge lamp is mounted after the protection operation, the supervisory control means responds to this and restores the auxiliary power supply voltage to the original value. For this reason, since the control circuit operates the inverter main circuit again as it was, the AC voltage is output to the load circuit, and the discharge lamp is lit with a predetermined brightness.

  In the present invention, since the control circuit is energized by one auxiliary power source whose voltage changes and operates as described above, the circuit configuration is simplified. Further, the monitoring control means of the control circuit can be configured using the UVLO function.

    According to a third aspect of the present invention, there is provided an illuminating device comprising: an illuminating device main body; and the discharge lamp lighting device according to the second aspect disposed in the illuminating device main body.

  In the present invention, the “illuminating device” is a broad concept including all the devices that utilize the light emission of the discharge lamp of the discharge lamp lighting device as defined in claim 2, for example, a lighting fixture, a marker lamp, an indicator lamp, This includes advertising lights. The “illuminating device main body” refers to the remaining part of the lighting device excluding the discharge lamp lighting device. The lighting device allows the fluorescent lamp to be lit in a space closed by a member such as a translucent glove or a shade. However, it may be configured to light up while being open to the outside. Furthermore, among the discharge lamp lighting devices, the discharge lamp is preferably arranged in the illuminating device main body, but the other components are arranged at positions separated from the illuminating device main body, and they are connected by wiring. Can be configured.

  And according to this invention, the illuminating device which has an effect | action and effect of the discharge lamp lighting device prescribed | regulated to Claim 2 can be obtained.

    According to the first aspect of the present invention, the control means includes the monitoring control means, and is energized by the auxiliary power source to start the operation of the inverter main circuit when the voltage of the auxiliary power source is the first voltage, and the load circuit The state at the predetermined position is monitored, and the protection operation is performed when the detection voltage of the state monitoring is the predetermined voltage, and the voltage of the auxiliary power source becomes the second voltage lower than the first voltage in conjunction with the protection operation. Sometimes suitable for performing discharge lamp mounting monitoring / protection operation using the UVLO function to change the voltage of the auxiliary power supply to a third voltage lower than the second voltage and continuously monitoring the state, and even after the protection operation An inverter device having a load monitoring / protection function that can be continuously monitored can be provided.

    According to the second aspect of the present invention, the control circuit includes the monitoring control means and is energized by the auxiliary power source to start the operation of the inverter main circuit when the voltage of the auxiliary power source is the first voltage. The mounting state of the discharge lamp is monitored, the auxiliary power source is controlled when the detection voltage of the state monitoring is a predetermined voltage, and the inverter main circuit is turned on when the voltage of the auxiliary power source becomes a second voltage lower than the first voltage. By controlling the protection operation and changing the voltage of the auxiliary power supply to a third voltage lower than the second voltage, and continuously monitoring the mounting state of the discharge lamp, the UVLO function is achieved. Therefore, it is possible to provide a discharge lamp lighting device that is suitable for use in monitoring and protecting a load and having a load monitoring and protecting function that can be continuously monitored even after the protecting operation.

    According to invention of Claim 3, the illuminating device which has an effect of invention of Claim 2 can be provided.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

    1 and 2 show a first embodiment for implementing an inverter device and a discharge lamp lighting device according to the present invention, FIG. 1 is a circuit diagram, and FIG. 2 is a voltage waveform diagram of each part. In FIG. 1, the discharge lamp lighting device includes an inverter device HFI and a discharge lamp DL, and its input terminals a and b are connected to a commercial low-frequency AC power source AC.

  The inverter device HFI includes a DC power source DC, an inverter main circuit INV, a load circuit LC, and a control circuit CC.

  The DC power source DC includes a bridge-type full-wave rectifier circuit BFR and a smoothing capacitor C1. The AC input terminal of the bridge-type full-wave rectifier circuit BFR is connected to the input terminals a and b of the discharge lamp lighting device via a noise prevention circuit (not shown). The smoothing capacitor C1 is connected between the DC output terminals of the bridge-type full-wave rectifier circuit BFR.

  The inverter main circuit INV is formed of a half-bridge inverter, and includes a pair of switching elements Q1 and Q2 and a drive circuit GDC whose main ends are connected in series. The pair of switching elements Q1 and Q2 connected in series is an N-type MODFET and is connected to both ends of the smoothing capacitor C1 of the DC power source DC. The drive circuit GDC drives the pair of switching elements Q1, Q2 as a half-bridge inverter by alternately applying gate drive signals that are 180 ° out of phase between the gates and sources of the pair of switching elements Q1, Q2.

  The load circuit LC is composed of a series circuit of a direct current cut capacitor C2, an inductor L1, and a resonance capacitor C3, and is connected in parallel to the switching element Q2 of the inverter main circuit INV.

  The auxiliary power supply SS includes an integration circuit IC and a clamp circuit CL. The integrating circuit IC is constituted by a series circuit of a resistor R1 and a capacitor C4, and one end on the resistor R1 side is connected to the positive electrode of the DC power source DC, and the other end on the capacitor C4 side is connected to the negative electrode. The output voltage of the auxiliary power supply SS is obtained from both ends of the capacitor C4. The clamp circuit CL is configured by a series circuit of a plurality of zener diodes ZD1 and ZD2, and is connected in parallel to the capacitor C4 of the integration circuit IC.

  The control circuit CC is composed of a control circuit body CC1 and monitoring control means CC2, and is energized by the auxiliary power supply SS. The control circuit body CC1 is configured such that its control output is control-inputted to the drive circuit DC of the inverter main circuit INV. When the operation starts, the control circuit body CC1 sends an activation signal to the drive circuit DC of the inverter main circuit INV to activate the inverter main circuit INV.

  The supervisory control means CC2 is composed of a load circuit voltage detection circuit VD, a resistor R4, and a switch SW1. In the load circuit voltage detection circuit VD, the resistors R2 and R3 form a voltage dividing circuit, and the voltage of the auxiliary power supply SS is applied to the voltage dividing circuit via the resistor R4. Further, one end of the voltage dividing circuit on the resistor R2 side is connected to a non-power supply side terminal to a filament electrode E2 on the low side of the discharge lamp DL described later. Further, a capacitor C5 is connected in parallel to the resistor R3 of the voltage dividing circuit. The switch SW1 is composed of a bipolar transistor, and its collector / emitter is connected to the Zener diode ZD2 of the clamp circuit CL of the auxiliary power supply SS so that it can be short-circuited, and its base / emitter is connected to both ends of the resistor R3 of the load circuit voltage detection circuit VD. doing.

  The discharge lamp DL is a fluorescent lamp and includes a pair of filament electrodes E1 and E2. The pair of filament electrodes E1 and E2 are inserted in series with the load circuit LC. Further, the discharge lamp DL is connected in parallel to the resonance capacitor C3 of the load circuit LC.

  Next, the circuit operation of the first embodiment will be described with reference to FIG. 2A shows the voltage of the auxiliary power supply, and FIG. 2B shows the output voltage of the inverter main circuit.

  In FIG. 2A, when the low-frequency AC power supply AC is turned on at time t0, the voltage between the output terminals of the auxiliary power supply SS increases exponentially by the action of the integration circuit IC. When the voltage of the auxiliary power supply SS becomes the first voltage V1 at time t1, the control circuit body CC1 starts to operate and sends a start signal to the drive circuit GDC. Note that the voltage of the auxiliary power supply SS is clamped at a constant value after the clamp circuit CL operates at a value exceeding the first voltage V1.

  When the activation signal is received, the drive circuit GDC starts to operate and drives the inverter main circuit INV, so that a high frequency voltage is generated between both ends of the switching element Q2, as shown in FIG. This high frequency voltage is applied to the load circuit LC.

  However, when the discharge lamp DL is not attached to the load circuit LC, since the pair of filament electrodes E1 and E2 are not inserted in series in FIG. 1, the potential of the load circuit voltage detection circuit VD is the voltage of the auxiliary power supply SS. Is equal to The voltage of the auxiliary power supply SS at this time exceeds the first voltage V1 as described above, but the switch SW1 of the monitoring control means CC2 is turned on at time t3. When the switch SW1 is turned on, the Zener diode ZD2 is short-circuited, so that the clamp voltage of the clamp circuit CL becomes low, so that the terminal voltage of the capacitor C4 of the integration circuit IC decreases exponentially from time t3.

  When the voltage of the auxiliary power supply SS starts to decrease and reaches the second voltage V2 at time t4, the control circuit body CC1 stops its operation. As a result, the drive circuit GDC stops operating in conjunction with each other, so that the inverter main circuit INV stops operating and no high-frequency voltage is output.

  The voltage of the auxiliary power supply SS is further decreased by turning on the switch SW1, and is decreased to a third voltage equal to the Zener voltage of the Zener diode ZD1, and thereafter the third voltage is maintained. Note that the third voltage is lower than the second voltage.

  Since the third voltage is applied from the auxiliary power supply SS even after the inverter main circuit INV stops operating, the monitoring control means CC2 continues monitoring the mounting of the discharge lamp DL. When the discharge lamp DL is mounted, the potential of the non-power supply side terminal of the filament electrode E2 becomes low, and this can be sensed. That is, since the base potential of the switch SW1 is lowered, the switch SW1 is turned off.

  When the switch SW1 of the monitoring control means CC2 is turned off, the voltage of the auxiliary power supply SS is restored and becomes the first voltage V1, so that the inverter main circuit INV starts to operate again via the control circuit body CC1. When the inverter main circuit INV starts operation, a high frequency voltage is output.

  The generated high frequency voltage is applied to the load circuit LC. Since the load circuit LC moderately resonates in series with the applied high frequency voltage, the terminal voltage of the resonance capacitor C3 increases. Since this high voltage is applied between the pair of filament electrodes E1 and E2 of the discharge lamp DL, the discharge lamp DL is easily started and lit. The high-frequency voltage output from the inverter main circuit INV has a rectangular wave shape, but is shaped into a sine wave by series resonance in the load circuit LC. Although not described, the control circuit CC can control the inverter main circuit INV to operate in the preheating mode before the discharge lamp DL is started. And it controls so that it may transfer to the mode mentioned above, ie, starting mode, in anticipation when a filament electrode will be in a thermoelectron emission state.

    FIG. 3 is a circuit diagram showing a second embodiment for carrying out the inverter device and the discharge lamp lighting device of the present invention. In the figure, the same parts as those in FIG. In this embodiment, the configuration of the auxiliary power supply SS is different.

  That is, in this embodiment, the auxiliary power supply SS is provided with a series stabilized power supply SSV called a series regulator instead of the clamp circuit CL. The stabilized power supply circuit SSV includes a transistor Q3, two sets of constant voltage elements ZD3 and ZD4, and a resistor R5. The collector and emitter of the transistor Q3 are inserted in series between the capacitor C4 of the integration circuit IC and the control circuit CC. The two sets of constant voltage elements ZD3 and ZD4 are composed of a pair of Zener diodes. These Zener diodes have a difference in height between the Zener voltages, and are connected in parallel to the base of the transistor Q3. The resistor R5 is connected between the emitter and base of the transistor Q3.

  The switch SW1 of the monitoring control means CC2 of the control circuit CC is connected in series with the constant voltage element ZD4 having the lower Zener voltage.

  Then, in the state where the power is turned on and the input terminals a and b of the discharge lamp lighting device are connected to the commercial low-frequency AC power supply AC, the switch SW1 of the monitoring control means CC2 is off, so the auxiliary power supply SS Only the constant voltage element ZD3 is connected to the base of the transistor Q3 of the series stabilized power supply SSV. The Zener voltage of the constant voltage element ZD3 is relatively high. Therefore, the auxiliary power supply SS outputs a voltage exceeding the first voltage V1 from the series stabilized power supply SSV.

  When the monitoring control means CC2 detects that the discharge lamp DL is not attached, the switch SW1 is turned on, so that the constant voltage element ZD4 is connected in parallel to the constant voltage element ZD3. Since the Zener voltage of the constant voltage element ZD4 is relatively low, the constant voltage element ZD3 does not operate, and the auxiliary power supply SS outputs the third voltage V3 from the series stabilized power supply SSV. In this state, the non-mounting of the discharge lamp DL is continuously monitored after the protection operation for the non-mounting of the discharge lamp DL. Therefore, when the discharge lamp DL is mounted, the auxiliary power supply SS is controlled to output a voltage exceeding the first voltage. Other circuit operations are the same as those in the first embodiment shown in FIG.

    FIG. 4 is a perspective view showing a ceiling-mounted fluorescent lamp apparatus as an embodiment for carrying out the lighting device of the present invention. In the figure, 1 is a lighting fixture body, 2 is a discharge lamp, and 3 is a lighting circuit.

  The luminaire main body 1 has a trough shape, a reflective paint is applied to the outer surface, and lamp sockets 1a and 1a are disposed on the lower surfaces of both ends in the longitudinal direction.

  The discharge lamp 2 is a fluorescent lamp and is mounted between a pair of lamp sockets 1a and 1a.

  The lighting circuit 3 has the circuit configuration shown in FIG.

The circuit diagram which shows the 1st form for implementing the inverter apparatus and discharge lamp lighting device of this invention Similarly, voltage waveform diagram of each part The circuit diagram which shows the 2nd form for implementing the inverter apparatus and discharge lamp lighting device of this invention The perspective view which shows the ceiling direct attachment type fluorescent lamp fixture as one form for implementing the illuminating device of this invention

Explanation of symbols

  CC ... control circuit, CC1 ... control circuit body, CC2 ... monitoring control means, CL ... clamp circuit, DC ... DC power supply, DL ... discharge lamp, IC ... integration circuit, INV ... inverter main circuit, LC ... load circuit, SS ... Auxiliary power

Claims (3)

DC power supply;
An inverter main circuit including at least one switching element, having an input terminal connected to a DC power source and outputting an AC voltage to an output terminal;
A load circuit connected to the output terminal of the inverter main circuit;
Including a monitoring control means, which is energized by the auxiliary power supply, starts the operation of the inverter main circuit when the voltage of the auxiliary power supply is the first voltage, and detects the state monitoring by monitoring the state at a predetermined position of the load circuit The protection operation is performed when the voltage is a predetermined voltage, and the voltage of the auxiliary power supply is set to be higher than the second voltage when the voltage of the auxiliary power supply becomes a second voltage lower than the first voltage in conjunction with the protection operation. A control circuit for changing to a lower third voltage and subsequently monitoring the state;
An inverter device comprising: An inverter device according to claim 1;
A discharge lamp comprising a filament electrode and connected to the load circuit of the inverter device;
Comprising
The load circuit includes a series circuit of an inductor and a capacitor;
The discharge lamp is connected in parallel with the capacitor of the load circuit;
The control circuit includes monitoring control means, and is energized by the auxiliary power source to start the operation of the inverter main circuit when the voltage of the auxiliary power source is the first voltage and to monitor the mounting state of the discharge lamp of the load circuit. The auxiliary power supply is controlled when the detection voltage for state monitoring is a predetermined voltage, and when the auxiliary power supply voltage becomes a second voltage lower than the first voltage, the inverter main circuit is controlled to perform a protection operation. At the same time, the auxiliary power supply voltage is changed to a third voltage lower than the second voltage to continuously monitor the mounting state of the discharge lamp;
A discharge lamp lighting device characterized by that. A lighting device body;
A discharge lamp lighting device according to claim 2, which is disposed in a lighting device body;
An illumination device comprising:

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