JP4899486B2 - Discharge lamp lighting device and lighting fixture - Google Patents

Description

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

  FIG. 11 is a circuit diagram of a conventional example disclosed in Patent Document 1. In FIG. Hereinafter, the circuit configuration will be described.

  A series circuit of switching elements Q1, Q2 is connected to the DC power source E. Each switching element Q1, Q2 is made up of a power MOSFET, and a drive signal for alternately turning on / off is supplied from the drive circuit 2 of the control circuit section 1 to the gate terminal via the resistors R1, R2. A series circuit of a resonance (current limiting) inductor L1 and a resonance capacitor C1 is connected to both ends of one switching element Q2 via a DC cut capacitor C0. A discharge lamp La as a load is connected in parallel to both ends of the resonance capacitor C1. The discharge lamp La is a hot cathode type discharge lamp such as a fluorescent lamp, and includes a pair of filaments. The switching elements Q1, Q2, the DC cut capacitor C0, the resonance (current limiting) inductor L1, the resonance capacitor C1, and the discharge lamp La constitute an inverter circuit. A resistor R0 is connected in parallel to the DC cut capacitor C0.

  The inductor L1 includes a pair of secondary windings, and one filament terminal A, B of the discharge lamp La is connected between the terminals a, b of the first secondary winding via a capacitor C2. The other filament terminals C and D of the discharge lamp La are connected between the terminals c and d of the second secondary winding via a capacitor C3. Each secondary winding of the inductor L1 that supplies current to the filament of the discharge lamp La and capacitors C2 and C3 that control the amount of current flowing through the filament constitute a filament preheating circuit.

  The control circuit unit 1 that controls the switching elements Q1 and Q2 includes a frequency control circuit 3 that controls the frequency at which the switching elements Q1 and Q2 are alternately turned on and off. This frequency control circuit 3 has a frequency fph in a pre-heating mode in which the filament is heated until a predetermined time elapses after the power is turned on, and then a starting voltage for starting the lighting of the load until a predetermined time elapses. It has a timer function that shifts to the frequency fst to be applied and then to the frequency ft at which a predetermined load output state is obtained.

  The control circuit unit 1 includes predetermined comparators NL and EL. The output of the comparator NL starts oscillation of the inverter circuit when High and stops oscillation when Low. The output of the comparator EL is High to stop the inverter circuit. However, during preheating / starting, the function of stopping the inverter circuit by the output of the comparator EL is prohibited.

  This discharge lamp lighting device includes a low-pressure side no-load detection circuit for detecting whether or not a low-pressure side filament of the discharge lamp La is connected, and no start-up for detecting whether or not the discharge lamp La is connected when the inverter circuit is started. A load detection circuit and a DC component detection circuit for a voltage (lamp voltage) applied to the discharge lamp La are provided.

  First, the low voltage side no-load detection circuit will be described. A resistor R8 is connected between the positive electrode of the DC power source E and the filament terminal D on the low pressure side of the discharge lamp La, and resistors R12 and R13 are connected between the filament terminal D and the negative electrode (ground line) of the DC power source E. Are connected in series. A capacitor C7 is connected in parallel across the resistor R13, and its potential VD is applied between the base and emitter of the transistor Q3. These resistors R8, R12, R13, capacitor C7, transistor Q3, and filament terminals C, D constitute a low voltage side no-load detection circuit.

  Next, the startup no-load detection circuit will be described. A resistor R5 is connected between the positive electrode of the DC power supply E and the filament terminal B on the high voltage side of the discharge lamp La, and a resistor is connected between the filament terminal A on the high voltage side and the negative electrode (ground line) of the DC power supply E. A series circuit of R9, R10 and a Zener diode ZD1 is connected. A resistor R11 and a capacitor C6 are connected in parallel to both ends of the Zener diode ZD1 via the diode D1, and the potential VC is connected to the plus side input terminal of the comparator NL. These resistors R5, filament terminals B and A, resistors R9 and R10, Zener diode ZD1, diode D1, resistor R11, and capacitor C6 constitute a start-up no-load detection circuit.

  Next, a first DC component detection circuit that detects a DC component of the lamp voltage will be described. A series circuit of resistors R3 and R4 is connected between the connection point of the DC cut capacitor C0 and the inductor L1 and the negative electrode (ground line) of the DC power supply E. A capacitor C4 is connected in parallel to both ends of the resistor R4, and the potential VA is connected to the positive side input terminal of the comparator EL via the diode D2. These resistors R3 and R4 and capacitor C4 constitute a first DC component detection circuit.

  Next, a second DC component detection circuit that detects a DC component of the lamp voltage will be described. A series circuit of resistors R6 and R7 is connected between the filament terminal B and the negative electrode (ground line) of the DC power supply E. A capacitor C5 is connected in parallel to both ends of the resistor R7, and the potential VB is connected to the plus side input terminal of the comparator EL via the diode D3. These resistors R6, R7 and capacitor C5 constitute a second DC component detection circuit.

  The operation of the conventional example will be described below. In the inverter circuit, the switching elements Q1 and Q2 are alternately turned on and off by a drive signal from the control circuit unit 1 to the switching elements Q1 and Q2, and the inverter circuit is rectangular in a resonant load circuit including the inductor L1, the capacitor C1, and the discharge lamp La. A wave-like high-frequency voltage is applied to light the discharge lamp La with a sinusoidal high-frequency wave. Here, the on-duty ratio of the switching elements Q1 and Q2 operates at about 50%.

  FIG. 12 shows the relationship between the inverter operating frequency and the resonance voltage of the capacitor C1. In the figure, fph is the operating frequency during preheating, fst is the operating frequency during startup, ft is the operating frequency during lighting, and fo is the no-load resonance frequency. When the power is turned on, the inverter circuit oscillates at a frequency fph (preceding preheating frequency) which is higher than the no-load resonance frequency fo determined by the inductor L1 and the capacitor C1 by the control circuit unit 1 and does not light the discharge lamp La. The discharge lamp La is applied with a resonance voltage lower than that at the start. At this time, a current is passed through the filament via the capacitors C2 and C3 by the voltage generated in the secondary winding of the inductor L1 to heat the filament (advance preheating mode). After pre-heating for a predetermined time, the operating frequency of the inverter changes to a frequency fst (starting voltage application frequency) so that the discharge lamp La can be lit, and a resonance voltage is applied so that the discharge lamp La can be lit. The light La is turned on (starting mode). Thereafter, the frequency changes to ft (lighting frequency) and shifts to a normal lighting state (lighting mode).

  Here, the conventional example has a function of detecting that the discharge lamp La is disconnected and stopping the oscillation of the inverter circuit, and the operation thereof will be described.

  First, when the power is turned on with the filament terminals A, B, C, and D connected, the filament terminals D and C and the resistor terminals R8 of the low-voltage side no-load detection circuit from the DC power source E are connected to this. A DC bias is applied through a path of resistors R12 and R13 and a capacitor C7 connected in parallel. However, the filament resistance value is approximately several Ω to several tens of Ω, and the resistors R8, R12, and R13 are configured with values of several tens of kΩ to several MΩ so as not to affect the resonant load circuit. Since the DC bias applied between them is extremely low and there is almost no DC bias of the resistor R13 connected between the base and emitter of the transistor Q3, the transistor Q3 is turned off.

  Further, a DC bias is applied from the DC power source E through the path of the resistor R5, filament terminals B and A, resistors R9 and R10, Zener diode ZD1, diode D1, resistor R11, and capacitor C6 of the startup no-load detection circuit. At this time, since the transistor Q3 is off, the DC bias of the resistor R11 and the capacitor C6 is not affected by the resistor R14, and a voltage with a voltage division ratio determined by only the resistor constituting the no-load detection circuit at start-up is applied. . As a result, a DC bias equal to or higher than the reference voltage Ref-NL is applied to the comparator NL, the output of the comparator NL becomes High, and the inverter circuit starts to oscillate.

  At this time, since the discharge lamp La is not lit, the DC voltage VA determined by a predetermined voltage division ratio is applied to the capacitor C4 of the first DC component detection circuit, and the reference voltage Ref-EL is applied via the diode D2. In some cases, a voltage exceeding the voltage is input to the comparator EL, but the comparator EL prohibits the detection operation in the preceding preheating mode and the start mode.

  Similarly, since the discharge lamp La is not lit on the capacitor C5 of the second DC component detection circuit, the DC voltage VB determined by a predetermined voltage division ratio is applied and exceeds the reference voltage Ref-EL via the diode D3. Although voltage may be input to the comparator EL, the comparator EL prohibits the detection operation in the preceding preheating mode and the start mode.

  When the power is turned on with the filament terminal A or B disconnected, the DC bias from the DC power source E of the start-up no-load detection circuit described above is cut off by the capacitor C2, and therefore the potentials of the resistor R11 and the capacitor C6 VC does not increase, and the input voltage to the positive input terminal of the comparator NL is lower than the reference voltage Ref-NL regardless of whether the transistor Q3 is on or off. Therefore, the output of the comparator NL is Low, and the inverter circuit stops oscillating. .

  When the filament terminal C or D is disconnected, the impedance between the filament terminals C-D is only the capacitor C3, and the DC impedance is infinite, so that the base emitter of the transistor Q3 of the low-voltage side no-load detection circuit Since the bias determined by the resistors R8, R12, and R13 is supplied between them, the transistor Q3 is turned on. The resistor R14 is connected to the filament terminal A-B, and even if a bias higher than the reference voltage Ref-NL is input to the resistor R11, the resistor R14 has a resistance value that reduces it to a bias lower than the reference voltage Ref-NL. Yes. That is, regardless of the connection of the filament terminal A-B, when the filament terminal C or D is disconnected, the transistor Q3 is turned on and the inverter circuit stops oscillation.

  Next, the case where the filament terminals A, B, C, and D are disconnected while the discharge lamp La is turned on will be described. First, when the filament terminal C or D is disconnected during lighting, since the DC bias is supplied to the base of the transistor Q3 in the same manner as when the filament terminal C or D is disconnected when the power is turned on, the transistor Q3 is turned on. Then, the input voltage to the positive input terminal of the comparator NL falls below the reference voltage Ref-NL, and the inverter circuit stops oscillating.

  Next, the case where the filament terminals A and B are disconnected will be described. When the discharge lamp La is turned on, the impedance of the discharge lamp La decreases from infinity to several hundred Ω. In addition, the impedance of the resistor of the start-up no-load detection circuit is several tens of kΩ to several MΩ to suppress the power loss in the resistor so that the resonance circuit is not affected. Is set to a sufficiently large value. As a result, the DC bias from the DC power source E to the resistors R9, R10, and R11 of the start-up no-load detection circuit is almost eliminated because the resistance voltage division ratio is extremely decreased due to the influence of the impedance on the discharge lamp La side. However, when the inverter circuit starts to oscillate, a high-frequency voltage is generated at both ends of the capacitor C1 and the discharge lamp La, and this high-frequency voltage is converted into a voltage obtained by half-wave rectification and peak value clamping by the Zener diode ZD1, and this is converted to the diode D1. The voltage VC of the capacitor C6 input to the comparator NL is held by rectifying and smoothing with the resistor R11 and the capacitor C6.

  In the first and second DC component detection circuits, when the discharge lamp La is lit, the switching elements Q1 and Q2 operate at a duty ratio of 50%, so that almost no DC component is applied to the discharge lamp La. For this reason, the potentials VA and VB of the resistors R4 and R7 are almost 0 V because the high frequency component is not applied by the capacitors C4 and C5 connected in parallel and the DC component is divided and detected.

  If a connection failure occurs in the A terminal of the filament while the discharge lamp La is lit, the lamp current of the discharge lamp La on the inverter circuit normally flows through the A terminal of the filament, but the path is cut off, so that the inductor Current continues to flow through the terminals a and b of the L1 secondary winding (preheating winding), the capacitor C2, and the B terminal of the filament. At this time, if the capacitance of the capacitor C2 is a capacitance that does not greatly affect the resonant load circuit, there is almost no fluctuation in the output of the discharge lamp La, and the resonant voltage generated there is also the same, so the input to the comparator NL There is no change in voltage.

  FIGS. 13 and 14 show equivalent circuits and operation waveforms when the filament terminal A is defectively connected. In these drawings, the first DC component detection circuit is denoted as Z3, the circuit portion having a resistance R9 or less of the startup no-load detection circuit is denoted as Z9, and the second DC component detection circuit is denoted as Z6. From this equivalent circuit, when the filament terminal A becomes poorly connected, the capacitor C2 is inserted in the lamp current path, and the DC cut capacitor on the inverter circuit is such that the capacitor C2 is added to the capacitor C0. It becomes.

  During normal lighting, about half of the voltage of the DC power source E is applied to the capacitor C0. However, when the filament terminal A is poorly connected, the voltage applied to the capacitor C0 and the capacitor C2 is the resistance R0 and the detection circuit. It is determined by the DC resistance voltage division ratio of Z3 and Z9. A DC voltage corresponding to the voltage division ratio is applied to the capacitor C2. Here, the detection circuit Z6 is connected in parallel to the discharge lamp La, but the impedance of the discharge lamp La is very small compared to the impedance constituting the detection circuit Z6 and can be almost ignored.

  In this state, the first DC component detection circuit Z3 detects the DC component voltage applied to the series circuit of the discharge lamp La and the capacitor C2, so that the DC component of the discharge lamp La is almost 0V. In addition, since the DC component voltage of the capacitor C2 is detected by the resistance divided voltage of the resistors R3 and R4, the detection voltage becomes higher than that during normal lighting, and a voltage exceeding the reference voltage Ref-EL is input to the comparator EL, and the inverter Stops the circuit from oscillating.

The operation waveforms at this time are shown in FIG. 14, in which V _La is the voltage across both ends of the discharge lamp La (lamp voltage), and V _La + VC2 is the capacitor C2 and the discharge lamp when the filament terminal A becomes poorly connected. The applied voltage to the series circuit of La is shown, DC shown here is showing the direct-current voltage shared by the capacitor | condenser C2 mentioned above, and DC 'is applied to resistance R4 which comprises the detection circuit Z3. This is the detection voltage.

  FIGS. 15 and 16 show equivalent circuits and operation waveforms when the filament terminal B becomes defective in connection. From this equivalent circuit, when the filament terminal B becomes poorly connected, the lamp current path does not change and continues to flow through the filament terminal A. In this state, the capacitor C2 is inserted between the second DC component detection circuit Z6 and the discharge lamp La. At this time, the detection voltage of the second DC component detection circuit Z6 has a configuration in which the DC power source E is divided by the resistor R5 and the detection circuit Z6. That is, the capacitor C2 is not affected by the impedance of the discharge lamp La, and a voltage obtained by dividing the DC power source E by the resistors R5, R6, and R7 is applied to the resistor R7 and the capacitor C5. The inverter circuit stops oscillating.

  According to this conventional example, even if one end of the filament terminal becomes poorly connected, in the inverter circuit where the lamp current path exists, it is possible to easily detect the one end poorly connected state, and furthermore, detect the one end poorly connected state. In this case, the inverter circuit can be controlled to a predetermined state. Therefore, it is possible to prevent continuous oscillation in a state where the filament terminal is poorly connected.

In addition, since it does not shift to the arc generation mode that occurs when one end of the filament terminal is poorly connected and the other end becomes poorly connected, it is possible to provide an inverter circuit with excellent safety requirements with a relatively inexpensive configuration and detection accuracy. High protection circuit can be realized.
JP 2004-193074 A

  By the way, in the above conventional example, the following malfunction may occur although it is very rare. In other words, although the discharge lamp La is not in the end-of-life state and is in a normal state in which the filament is not disconnected, the discharge lamp La immediately after the lighting mode transitions due to various variations in the discharge lamp La. A DC component may be applied between the La filament and the high and low pressure filaments. For example, when a positive direct current component is applied in the direction of terminals C to D in the low pressure side filament immediately after the lighting mode transition, and at the same time a positive direct current component is applied in the direction of the high pressure side filament from the low pressure side filament. In the low voltage side no-load detection circuit, the transistor Q3 is turned on, the input voltage to the positive input terminal of the comparator NL is lower than the reference voltage Ref-NL, and in the first DC component detection circuit, the detection voltage is from the normal lighting state. The voltage becomes higher than the reference voltage Ref-EL, and the detected voltage becomes higher than that during normal lighting, and the voltage higher than the reference voltage Ref-EL is input to the comparator EL. That is, the oscillation of the inverter circuit is stopped by any detection. After that, since the filament is normal, no-load detection at start-up does not operate, the inverter circuit resumes operation from the preceding preheating mode, and immediately after switching to the lighting mode through the start mode, the low-voltage side no-load detection circuit again Alternatively, either the first DC component detection circuit or the second DC component detection circuit operates to stop oscillation.

  Such an operation is repeated endlessly, and the preceding preheating mode and the start mode are continuously repeated, so that not only the stress on each part of the circuit such as the transistors Q1 and Q2 is increased, but also the user is uncomfortable. there were.

  In order to solve the above problems, a flip-flop (not shown) is employed instead of the comparator EL, and the detection time constants of the first DC component detection circuit and the second DC component detection circuit are set to the low voltage side. There is a method of making it smaller than the detection time constant of the no-load detection circuit. Depending on this method, immediately after the transition to the lighting mode, a positive direct current component is applied in the direction of the terminals C to D in the low pressure side filament, and at the same time, a positive direct current component is applied in the direction of the high pressure side filament from the low pressure side filament. In this case, the detection time constant of the first DC component detection circuit or the second DC component detection circuit is smaller than the detection time constant of the low-voltage side no-load detection circuit. However, since the oscillation stop is maintained, there is no malfunction such as the preceding preheating mode and the start mode being continuously repeated, but the detection time constant of the low-voltage side no-load detection circuit must be relatively large, The detection speed (time required for detection) of a connection failure is different between the high pressure side and the low pressure side, and the detection speed on the low pressure side is different from that on the high pressure side. There is a problem that Kunar.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a discharge lamp lighting device and a luminaire that can detect a defective connection of a filament terminal and can reliably prevent malfunction of detection. is there.

In order to achieve the above object, the invention of claim 1 is an inverter circuit that converts a direct current input into a high frequency alternating current output and supplies it to the filament of a hot cathode discharge lamp, and adjusts the operating frequency of the inverter circuit. There are at least three operation modes in time series from the input start time of the DC input: a preheating mode for preheating the filament, a starting mode for starting a discharge lamp by applying a high voltage to the filament, and a lighting mode for rated lighting of the discharge lamp. Control means for switching, no-load detection means for detecting disconnection of the discharge lamp before starting the inverter circuit, and control means for stopping the inverter circuit when the disconnection of the discharge lamp is detected by the no-load detection means A first abnormality control means to be applied to the power supply, a disconnection detection means for detecting disconnection of the discharge lamp after the inverter circuit is started, and a disconnection detection means And second abnormality control means for giving a command to the control means to stop or limit the output of the inverter circuit when disconnection of the discharge lamp is detected, and first after the inverter circuit is started or after the discharge lamp is started. First invalidation means for invalidating the command output from the abnormality control means, and second invalidation means for invalidating the command output from the second abnormality control means until the discharge lamp is rated-lit. The second abnormality control means comprises a flip-flop in which the detection signal of the disconnection detection means is input to the set terminal, and the output signal for invalidating the command by the first invalidation means is input to the reset terminal. And

  According to a second aspect of the present invention, in the first aspect of the invention, the first abnormality control means and the second abnormality control means output from the no-load detection means and the disconnection detection means when the disconnection of the discharge lamp is detected. And a common input terminal for inputting a detection signal to be detected.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the first and second abnormality control means and the first and second invalidating means comprise one integrated circuit.

In order to achieve the above object, the invention according to claim 4 is an inverter circuit that converts a direct current input into a high frequency alternating current output and supplies it to a filament of a hot cathode discharge lamp, and adjusts the operating frequency of the inverter circuit. There are at least three operation modes in time series from the input start time of the DC input: a preheating mode for preheating the filament, a starting mode for starting a discharge lamp by applying a high voltage to the filament, and a lighting mode for rated lighting of the discharge lamp. Control means for switching, no-load detection means for detecting disconnection of the discharge lamp before starting the inverter circuit, and control means for stopping the inverter circuit when the disconnection of the discharge lamp is detected by the no-load detection means A first abnormality control means to be given to the battery, a life detection means for detecting the end of life state of the discharge lamp, and a life end of the discharge lamp by the life detection means A third abnormality control means for giving a command to the control means to stop or limit the output of the inverter circuit when a state is detected; and from the first abnormality control means after starting the inverter circuit or starting the discharge lamp. comprising: a first invalidation unit for invalidating the output commanding the discharge lamp and a third disabling means for disabling the instruction for outputting from the third abnormality control means until the rated lighting, the third anomaly The control means comprises a flip-flop in which the detection signal of the life detection means is input to the set terminal, and the output signal for invalidating the command by the first invalidation means is input to the reset terminal .

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the first abnormality control means and the third abnormality control means include a detection signal output from the no-load detection means when disconnection of the discharge lamp is detected. A common input terminal is provided for inputting a detection signal output from the life detecting means when the end of life state of the discharge lamp is detected.

  A sixth aspect of the invention is characterized in that, in the fourth or fifth aspect of the invention, the first and third abnormality control means and the first and third invalidating means are formed of one integrated circuit.

The invention of claim 7 is the invention according to any one of claims 1 to 6, wherein the control means changes the operating frequency of the inverter circuit in accordance with a dimming command given from the outside so that the discharge lamp is turned on at rated lighting. has also low light output dimming lights to cause dimming mode as the operation mode, the second invalidation means outputs the second abnormal control means when the control means is operating in the dimming mode The command is invalidated, and the third invalidating unit invalidates the command output from the third abnormality control unit when the control unit is operating in the dimming mode .

  The invention according to claim 8 is the invention according to claim 7, wherein the second or third disabling means adjusts the discharge lamp with a light output of less than 20% when the rated lighting is 100%. The command output from the second or third abnormality control means when the light is turned on is invalidated.

  According to a ninth aspect of the present invention, in any one of the first, second, fourth, and fifth aspects, the second abnormality control means issues a command to the control means when a detection signal is input from the disconnection detection means or the end of life state. It is characterized by latching.

  In order to achieve the above object, a tenth aspect of the invention provides a discharge lamp lighting device according to any one of the first to ninth aspects, a fixture main body to which the discharge lamp lighting device is attached, a The electric lamp is detachably mounted and includes a discharge lamp lighting device and a socket for electrically connecting the discharge lamp.

  According to the present invention, similarly to the conventional example, even if one end of the filament terminal becomes poorly connected, in the discharge lamp lighting device including the inverter circuit in which the lamp current path exists, it is possible to easily detect the one end poorly connected state. In addition, it can reliably prevent malfunctions in detection, and since it does not shift to the arc generation mode that occurs when the other end of the filament terminal is poorly connected, the inverter circuit with excellent safety is compared. In addition, it is possible to provide a protection function with high detection accuracy while preventing malfunctions such as the preceding preheating mode and the start mode being continuously repeated.

(Embodiment 1)
A circuit diagram of this embodiment is shown in FIG. In the present embodiment, a latch circuit F / F is used instead of the comparator EL, and the output of the comparator NL is input to the reset terminal R of the latch circuit F / F composed of an RS flip-flop. A resistor R15 is connected between the point input to the frequency control circuit 3 via the mask circuit MK2 and between the resistor R12 and the resistor R13, and a capacitor C8 is connected between the connection point of the resistors R12 and R15 and the ground. The DC component detection circuit is configured, and the potential VE of the capacitor C8 is input to the set input terminal S of the latch circuit F / F via the diode D4. The diode D1 is deleted and short-circuited in the start-up no-load detection circuit. In addition, the zener diode ZD1 is deleted, and after the start of the inverter circuit or the start of the discharge lamp La The first mask circuit MK1, which is the first invalidating means for invalidating the command (High level signal) output from the comparator NL, which is the abnormality control means, and the second abnormality control means, until the discharge lamp La is rated on. 11 is different from the conventional example shown in FIG. 11 in that a second mask circuit MK2 as second invalidating means for invalidating a command (latch signal) output from the latch circuit F / F is provided. The configuration is the same as that of the conventional example. Therefore, the same components as those in the conventional example are denoted by the same reference numerals and the description thereof is omitted.

  The latch circuit F / F outputs a latch signal (high level signal) from the output terminal Q to the first mask circuit MK1 when a voltage equal to or higher than a preset internal reference voltage is input to the set input terminal S. The output of the second mask circuit MK2 is input to the reset terminal R, and the latch of the latch circuit F / F is reset when the comparator NL operates before the inverter circuit is activated (the output terminal Q is set to the Low level). . This reset operation is performed to automatically release the latch when the discharge lamp La is replaced, for example.

  The low voltage side no-load detection circuit cannot detect the disconnection of the filament terminals C and D during lighting because the detection operation after the inverter circuit is activated is prohibited by the second mask circuit MK2. Therefore, by adding a third DC component detection circuit, it is possible to detect the disconnection of the filament terminals C and D during lighting. That is, in the normal state in which the filament terminals C and D are connected when the discharge lamp La is turned on, the potential VE of the capacitor C8 constituting the third DC component detection circuit is substantially 0 V, so that the latch circuit F / F latches. When no signal is output, but the filament terminal C or D is disconnected, the impedance between the filament terminals C-D becomes only the capacitor C3 and the DC impedance becomes infinite, and resistors R8, R12, Since a DC voltage determined by R15 and R13 is applied, a latch signal is output from the latch circuit F / F and the inverter circuit stops oscillating. Here, the on-voltage of the transistor is about 1V, whereas the internal reference voltage preset at the input terminal S of the latch circuit F / F is often about 5V for the purpose of improving noise resistance performance, etc. In order to change the levels of VD and VE, a resistor R15 is inserted between the resistors R12 and R13.

  On the other hand, in the start-up no-load detection circuit, it is necessary to rectify and smooth the high-frequency voltage generated at both ends of the discharge lamp La after the start mode so as to hold the potential VC of the capacitor C6 above the reference voltage Ref-NL of the comparator NL. Therefore, the Zener diode ZD1 and the diode D1 which are half-wave rectifier parts are not necessary, and depending on the type of the discharge lamp La, there is a low high frequency voltage at the time of lighting, but in the case of such a discharge lamp La In addition, it is not necessary to consider an increase in the size or increase in the number of the resistor R10 in order to design the resistor R11 to be relatively large and the resistor R10 to be relatively small in anticipation of high-frequency charging.

  Here, the operation of stopping oscillation (or output limitation) of the inverter circuit when the discharge lamp La is disconnected is basically the same as that of the conventional example, and thus the description thereof is omitted. On the other hand, although the discharge lamp La is not in the end-of-life state and is in a normal state in which the filament is not disconnected, the discharge lamp La immediately after shifting to the lighting mode due to various variation factors of the discharge lamp La. In the case where a DC component is applied between the La filament and the high-pressure filament and the low-pressure filament, the present embodiment prevents the occurrence of malfunctions in which the preceding preheating mode and the start mode are continuously repeated as follows. Yes.

  For example, when a DC component in the positive direction is applied in the direction from the terminals C to D in the low-voltage side filament immediately after the lighting mode transition, a DC component in the positive direction is applied in the direction from the low-voltage side filament to the high-pressure side filament. In the present embodiment, the command (High level signal) output from the comparator NL by the first mask circuit MK1 is invalidated, so that the latch circuit F / F always operates to output a latch signal, and the latch signal is The frequency is supplied to the frequency control circuit 3 without being invalidated by the second mask circuit MK2, and the oscillation stop (or output limitation) operation of the inverter circuit is maintained. As a result, the preceding preheating mode and the start mode are continuously repeated. It is possible to prevent malfunctions such as Moreover, as described in the problem to be solved by the invention, it is necessary to make the detection time constants of the first DC component detection circuit and the second DC component detection circuit smaller than the detection time constant of the low voltage side no-load detection circuit. As a result, the detection speed (time required for detection) of one end connection failure of the filament terminal that is lit is not different between the high pressure side and the low pressure side, and the detection speed on the low pressure side is slower than the high pressure side. can be solved.

  As described above, according to the present embodiment, in the inverter circuit in which the lamp current path exists even when one end of the filament terminal becomes defective in connection as in the conventional example, the one end connection defective state can be easily detected. Detection malfunctions can be reliably prevented, and since there is no transition to the arc generation mode that occurs when one end of the filament terminal is poorly connected and the other end becomes poorly connected, a highly safe inverter circuit is relatively inexpensive. In addition, it is possible to provide a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Note that the first and second DC component detection circuits are Emileless detection circuits (Lifetime) that detect that the discharge lamp La is in an end-of-life state (so-called Emires state) and half-wave discharge is generated and a DC component is applied. Therefore, the circuit can be protected by stopping the oscillation of the inverter circuit or limiting the output by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

(Embodiment 2)
A circuit diagram of this embodiment is shown in FIG. In the present embodiment, the parallel circuit of the DC cut capacitor C0 and the resistor R0 is inserted between the resonance capacitor C1 and the discharge lamp La, and the resistor R3 in the first DC component detection circuit is replaced with the resonance capacitor C1. And the point connected to the connection point of the discharge lamp La are different from those of the first embodiment, but other configurations and basic operations are the same as those of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In this embodiment, as shown in FIGS. 3 (a) and 3 (b), the equivalent circuit when the filament terminal A or B becomes defective in connection is different from that in Embodiment 1 (conventional example). Since the operation is basically the same as that of the first embodiment (conventional example), the description is omitted. Here, although the capacitor C0 is used for cutting the DC component, the same effect can be obtained even if a so-called double resonance circuit configuration is adopted by setting the capacitance of the capacitor C0 to a value that can contribute to resonance.

  As described above, in this embodiment as well as in the first embodiment, even if one end of the filament terminal becomes defective in connection, it is possible to easily detect the one-end connection failure in the inverter circuit in which the lamp current path exists. Detection malfunctions can be reliably prevented, and since there is no transition to the arc generation mode that occurs when one end of the filament terminal is poorly connected and the other end becomes poorly connected, a highly safe inverter circuit is relatively inexpensive. In addition, it is possible to provide a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

(Embodiment 3)
A circuit diagram of this embodiment is shown in FIG. This embodiment is an example in which the configuration of the discharge lamp La, which is a load in the second embodiment, is configured in a series of two lamps. The same components as those of the second embodiment are denoted by the same reference numerals, and the same operation is performed. Will not be described.

  In this embodiment as well as in the first and second embodiments, even if one end of the filament terminal becomes poorly connected, the inverter circuit in which the lamp current path exists can easily detect the one end poorly connected state and Malfunctions can be reliably prevented, and since the transition to the arc generation mode that occurs when the other end of the filament terminal is poorly connected and then the other end becomes poorly connected, a safe inverter circuit is relatively inexpensive. In addition, it is possible to realize a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

(Embodiment 4)
A circuit diagram of this embodiment is shown in FIG. The present embodiment is an example in which the preheating current of the filament of the discharge lamp La, which is the load in the second embodiment, is supplied from the preheating transformer L2 and the capacitor C9. That is, the secondary winding for filament preheating is not provided in the inductor L1, but the primary winding of the preheating transformer L2 is connected to both ends of the switching element Q2 via the capacitor C9, and the preheating transformer L2 is connected to the filament preheating. Secondary windings are provided. The same components as those of the second embodiment are denoted by the same reference numerals, and the description of the same operation is omitted.

  Also in this embodiment, in the inverter circuit where the lamp current path exists even if one end of the filament terminal becomes poorly connected as in the first to third embodiments, it is possible to easily detect the one end poorly connected state and to detect it. Malfunctions can be reliably prevented, and since the transition to the arc generation mode that occurs when the other end of the filament terminal is poorly connected and then the other end becomes poorly connected, a safe inverter circuit is relatively inexpensive. In addition, it is possible to realize a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

(Embodiment 5)
A circuit diagram of this embodiment is shown in FIG. In this embodiment, the first and second DC component detection circuits are configured by a common resistor R4 and a capacitor C4, the first and second DC component detection circuits, the low-voltage side no-load detection circuit, The point that the output terminal of each detection circuit of the load detection circuit is connected directly to the input terminal of the comparator NL and the latch circuit F / F directly or via the diodes D2 and D4, and the control circuit unit 1 is a so-called HVIC (High Voltage IC). However, the same components as those of the second embodiment are denoted by the same reference numerals, and the description of the same operation is omitted.

  The HVIC that constitutes the control circuit unit 1 includes, for example, an 8V / 24V CMOS, a 24V bipolar, and a 600V withstand voltage DMOS on the same chip by a 600V withstand voltage junction separation process using a multiple field plate structure. As a result, a low-voltage / high-voltage control / protection circuit, a 600 V level shift circuit, and a driver are realized on a single chip.

  In the present embodiment as well, in the inverter circuit where the lamp current path exists even if one end of the filament terminal becomes poorly connected as in the first to fourth embodiments, it is possible to easily detect the one end poorly connected state and to detect it. Malfunctions can be reliably prevented, and since the transition to the arc generation mode that occurs when the other end of the filament terminal is poorly connected and then the other end becomes poorly connected, a safe inverter circuit is relatively inexpensive. In addition, it is possible to realize a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Furthermore, since the outputs of all the detection circuits can be shared by one and the input terminal of the control circuit unit 1 becomes one, the HVIC package constituting the control circuit unit 1 can be downsized. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

(Embodiment 6)
A circuit diagram of this embodiment is shown in FIG. In the present embodiment, the detection outputs of the first and second DC component detection circuits, the low-voltage side no-load detection circuit, and the start-up no-load detection circuit are all supplied to the control circuit unit 1 through the microcomputer 10, and the first The function of the mask circuit MK1 of the second embodiment is different from that of the fifth embodiment in that it is realized by the microcomputer 10. However, the same components as those of the fifth embodiment are denoted by the same reference numerals, and the same operations will be described. Omitted.

  The microcomputer 10 controls the control circuit unit 1 in accordance with a dimming command (for example, a numerical value represented by an output ratio with 100% when the output of the inverter circuit is equal to the rated lamp power) given from the external dimmer 20. By controlling the frequency control circuit 3 and changing the operating frequency of the inverter circuit, the discharge lamp La has a function of dimming and lighting with a light output lower than that at the rated lighting.

  In the present embodiment as well, in the inverter circuit where the lamp current path exists even if one end of the filament terminal becomes poorly connected as in the first to fifth embodiments, it is possible to easily detect the one end poorly connected state and to detect it. Malfunctions can be reliably prevented, and since the transition to the arc generation mode that occurs when the other end of the filament terminal is poorly connected and then the other end becomes poorly connected, a safe inverter circuit is relatively inexpensive. In addition, it is possible to realize a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Further, since the microcomputer 10 has the function of the first mask circuit MK1, there is an advantage that it can be easily realized, and an inexpensive existing HV1C that does not have the function of the first mask circuit MK1 is used as the control circuit unit 1. it can. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply.

  Here, at the beginning of use of the discharge lamp La, the lamp is dimmed with lamp power lower than the rated lamp power, and is increased so as to approach the rated lamp power as the cumulative lighting time increases. A technique for saving energy while keeping the output of La substantially constant is already known (see, for example, Japanese Patent Laid-Open No. 2002-43086), but the cumulative lighting time of the discharge lamp La without using the dimmer 20 is known. The microcomputer 10 may be equipped with a timer function for measuring time.

(Embodiment 7)
A circuit diagram of this embodiment is shown in FIG. In the present embodiment, when the dimming command (dimming ratio) given from the dimmer 20 is less than a predetermined value, the third detection output of any of the first to third DC component detection circuits is invalidated. Although the difference from the sixth embodiment is that the mask circuit MK3 is provided, the same components as those of the sixth embodiment are denoted by the same reference numerals, and the description of the same operation is omitted.

  It is known that the impedance (lamp impedance) of the hot cathode discharge lamp La increases rapidly when the dimming ratio is less than about 20% (see FIG. 9). Therefore, in the region where the dimming command (dimming ratio) given from the dimmer 20 is less than a predetermined value (about 20%), for example, the detection of the first DC component detection circuit is performed although the filament is not abnormal. The voltage VA may exceed the reference voltage of the latch circuit F / F, and the inverter circuit may stop oscillating or the output may be limited due to erroneous detection of filament abnormality.

  Therefore, in the present embodiment, when the dimming command (dimming ratio) given from the dimmer 20 is less than 20%, the third mask circuit MK3 is one of the first to third DC component detection circuits. By invalidating the detection output, it is possible to prevent erroneous detection of filament abnormality in the region where the dimming ratio is less than 20% as described above. In the present embodiment, the third mask circuit MK3 is realized by the microcomputer 10.

  In the present embodiment as well, in the inverter circuit in which the lamp current path exists even if one end of the filament terminal becomes poorly connected as in the first to sixth embodiments, it is possible to easily detect the poorly connected end state and to detect it. Malfunctions can be reliably prevented, and since the transition to the arc generation mode that occurs when the other end of the filament terminal is poorly connected and then the other end becomes poorly connected, a safe inverter circuit is relatively inexpensive. In addition, it is possible to realize a protection function with high detection accuracy while preventing malfunction such as the preceding preheating mode and the start mode being continuously repeated. Since the first and second DC component detection circuits can also be used as the Emires detection circuit, the inverter circuit oscillation is stopped by detecting not only the filament connection failure but also the end-of-life state of the discharge lamp La. Alternatively, the output can be limited to protect the circuit. Further, the same effect can be obtained even if the command of the comparator NL is invalidated after the start mode in the first mask circuit MK1. Furthermore, the DC power supply E may be configured by an AC power supply and a circuit (for example, a boost chopper circuit) that rectifies and smoothes the AC power supply. Further, similarly to the sixth embodiment, the microcomputer 10 may be equipped with a timer function for measuring the cumulative lighting time of the discharge lamp La without using the dimmer 20.

  By the way, the discharge lamp lighting device of the first to seventh embodiments described above includes a substantially prismatic tool body 30 to which a discharge lamp lighting device (not shown) is attached, as shown in FIG. A luminaire (direct-attached type) provided with a pair of sockets 31 and 31 for electrically connecting the discharge lamp lighting device and the discharge lamp La while a straight tube-type discharge lamp La provided in the main body 30 is detachably mounted. Fluorescent lamp fixtures for facilities).

1 is a circuit diagram of Embodiment 1. FIG. FIG. 6 is a circuit diagram of a second embodiment. FIG. 4A shows an equivalent circuit when the filament terminal A becomes poorly connected, and FIG. 4B shows an equivalent circuit when the filament terminal B becomes poorly connected. FIG. 6 is a circuit diagram of a third embodiment. FIG. 6 is a circuit diagram of a fourth embodiment. FIG. 9 is a circuit diagram of a fifth embodiment. FIG. 10 is a circuit diagram of a sixth embodiment. FIG. 10 is a circuit diagram of the seventh embodiment. It is a graph which shows the relationship between the light control ratio and detection voltage in the same as the above. Embodiment of the lighting fixture of this invention is shown, (a) is a 1 light type perspective view, (b) is a 2 light type perspective view. It is a circuit diagram of a conventional example. It is a characteristic view which shows the relationship between an inverter operating frequency same as the above and a resonant voltage. It is an equivalent circuit diagram when the filament terminal A same as above becomes a connection failure. It is operation | movement explanatory drawing when the filament terminal A same as the above becomes a connection failure. It is an equivalent circuit diagram when filament terminal B same as the above becomes a connection failure. It is operation | movement explanatory drawing when the filament terminal B same as the above becomes a connection failure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control circuit part 2 Drive circuit 3 Frequency control circuit NL Comparator F / F latch circuit MK1 1st mask circuit MK2 2nd mask circuit

Claims (10)

An inverter circuit that converts DC input to high-frequency AC output and supplies it to the filament of a hot cathode type discharge lamp, a preheating mode that preheats the filament by adjusting the operating frequency of the inverter circuit, and a high voltage is applied to the filament A control means for switching at least three operation modes in time series from the input start time of the DC input, and a connection of the discharge lamp before starting the inverter circuit. A no-load detection means for detecting disconnection, a first abnormality control means for giving a command to the control means to stop the inverter circuit when disconnection of the discharge lamp is detected by the no-load detection means, Disconnection detecting means for detecting disconnection of the discharge lamp after start-up, and an inverter when disconnection of the discharge lamp is detected by the disconnection detecting means. Second abnormality control means for giving a command to the control means to stop or limit the output of the output circuit, and invalidate the command output from the first abnormality control means after starting the inverter circuit or starting the discharge lamp First invalidation means, and second invalidation means for invalidating a command output from the second abnormality control means until the discharge lamp is lit at rated power , the second abnormality control means being a disconnection detection means. The discharge lamp lighting device is characterized by comprising a flip-flop in which the detection signal is input to the set terminal and the output signal for invalidating the command by the first invalidating means is input to the reset terminal .   The first abnormality control unit and the second abnormality control unit have a common input terminal for inputting a detection signal output from the no-load detection unit and the disconnection detection unit when disconnection of the discharge lamp is detected. The discharge lamp lighting device according to claim 1.   3. The discharge lamp lighting device according to claim 1 or 2, wherein the first and second abnormality control means and the first and second invalidation means comprise one integrated circuit. An inverter circuit that converts DC input to high-frequency AC output and supplies it to the filament of a hot cathode type discharge lamp, a preheating mode that preheats the filament by adjusting the operating frequency of the inverter circuit, and a high voltage is applied to the filament A control means for switching at least three operation modes in time series from the input start time of the DC input, and a connection of the discharge lamp before starting the inverter circuit. A no-load detection means for detecting disconnection, a first abnormality control means for giving a command to the control means to stop the inverter circuit when disconnection of the discharge lamp is detected by the no-load detection means, Life detection means for detecting the end-of-life condition, and when the end-of-life condition of the discharge lamp is detected by the life detection means, the inverter circuit is stopped or Third abnormality control means for giving a command for output limitation to the control means, and a first invalidation for invalidating a command output from the first abnormality control means after starting the inverter circuit or after starting the discharge lamp And a third invalidating means for invalidating a command output from the third abnormality control means until the discharge lamp is rated-lit . The third abnormality control means is set with a detection signal of the life detecting means. A discharge lamp lighting device comprising a flip-flop that is input to a terminal, and an output signal that the first invalidating means invalidates the command is input to the reset terminal .   The first abnormality control means and the third abnormality control means detect the life when a detection signal output from the no-load detection means and the end-of-life condition of the discharge lamp are detected when disconnection of the discharge lamp is detected. 5. The discharge lamp lighting device according to claim 4, further comprising a common input terminal for inputting a detection signal output from the means.   6. The discharge lamp lighting device according to claim 4 or 5, wherein the first and third abnormality control means and the first and third invalidation means comprise one integrated circuit. The control means has, as an operation mode, a dimming mode in which the operation frequency of the inverter circuit is changed according to a dimming command given from the outside to dimm and light the discharge lamp with a light output lower than the rated lighting. second disabling means invalidates an instruction output from the second abnormality control means when the control means is operating in the dimming mode, the third disabling means, said control means adjusting The discharge lamp lighting device according to any one of claims 1 to 6, wherein a command output from the third abnormality control means is invalidated when operating in the light mode .   The second or third invalidating means is the second or third abnormality when the control means is dimming and lighting the discharge lamp with a light output of less than 20% when the rated lighting time is 100%. 8. The discharge lamp lighting device according to claim 7, wherein a command output from the control means is invalidated.   The second abnormality control means latches a command to the control means when a detection signal is input from the disconnection detection means or the end of life state. Discharge lamp lighting device.   The discharge lamp lighting device according to any one of claims 1 to 9, a fixture main body to which the discharge lamp lighting device is attached, a discharge lamp provided in the fixture main body is detachably mounted, and the discharge lamp lighting device and the discharge lamp are mounted. A lighting apparatus comprising a socket for electrically connecting an electric lamp.

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