JP2008204869A - Discharge lamp apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp apparatus in which, out of a plurality of discharge lamps connected in parallel, a lighting failure of one discharge lamp is certainly detected and a protective measure is taken. <P>SOLUTION: The discharge lamp apparatus is composed of a plurality of discharge lamps connected in parallel with an output side of a transformer 3 connected with an output side of a high frequency generating circuit 2. A magnetic body is wound by a plurality of winding wires 51 and flux detecting wires 52 which are connected in series with each of a plurality of the discharge lamps, and the flux detecting wires 52 detect that a total sum of fluxes generated in each of a plurality of the winding wires 51 becomes zero when all of the discharge lamps 4 are lit normally and detect that a total sum of fluxes generated in each of a plurality of the winding wire 51 does not become zero when at least one of the discharge lamps 4 becomes abnormal and thus an abnormality of at least one discharge lamp can be detected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a discharge lamp device, and more particularly to a discharge lamp device having a function of detecting an abnormality of a discharge lamp.

Patent Document 1 discloses a light source device in which a plurality of external electrode type rare gas fluorescent lamps are connected in parallel to at least one output transformer.
In Patent Document 2 and Patent Document 3, a plurality of EEFL lamps (External Electrofluorescent Lamps) are lit in parallel, and lighting sensors for individually detecting lighting and extinguishing at positions close to the EEFL lamps. There is shown a backlight unit that is provided with a (pattern coil, metal plate sensor), stops the inverter when any EEFL lamp is abnormal and becomes unlit, and performs a protective operation.
JP 2006-216391 A JP 2005-174909 A JP 2005-327725 A

However, the lighting sensors shown in Patent Document 2 and Patent Document 3 need to be as close as possible to the EEFL lamp in order to increase detection sensitivity. For this reason, as shown in FIG. 9 of Patent Document 3, the lighting sensor is installed on the reflection mirror in the lamp house. However, since the shadow is generated by the lighting sensor, the light output of the backlight unit may be reduced. There is.
In addition, when the lighting sensor as described above is applied to a rare gas fluorescent lamp in which external electrodes are arranged along the tube axis direction on the outer surface of a glass tube as shown in FIG. Since a high voltage is applied to the electrodes, if the lighting sensor is brought close to a rare gas fluorescent lamp, there is a possibility of dielectric breakdown, which is dangerous.
Furthermore, as described in Patent Document 2, since the output of the lighting sensor is easily influenced by individual differences of lamps, routing of the substrate pattern, installation state, ambient temperature, etc., in order to prevent malfunction due to those effects. There is a problem that the number of parts increases and the lighting circuit becomes complicated and large.

  In view of the above problems, the object of the present invention is that there is no risk of a decrease in light output or dielectric breakdown caused by arranging a lighting sensor in the vicinity of the discharge lamp, and individual differences of the discharge lamp, routing of the substrate pattern, Without adding a circuit to prevent malfunction due to the influence of the installation state, ambient temperature, etc., even if one of the multiple discharge lamps connected in parallel is not lit, it is reliably detected and protected operation An object of the present invention is to provide a lamp device having a function of performing the above.

The present invention employs the following means in order to solve the above problems.
The first means is a discharge comprising a high frequency generation circuit, the transformer having the output side of the high frequency generation circuit connected to the primary side of the transformer, and a plurality of discharge lamps connected in parallel to the secondary side of the transformer. In the lamp device, a plurality of windings and a magnetic flux detection winding connected in series to each of the plurality of discharge lamps are wound around a magnetic material, and all the discharge lamps are normally lit by the magnetic flux detection winding. And detecting that the sum of magnetic fluxes generated in each of the plurality of windings becomes zero, and generating magnetic fluxes in each of the plurality of windings when at least one discharge lamp becomes abnormal. A discharge lamp abnormality detecting circuit for detecting that at least one of the plurality of discharge lamps has become abnormal by detecting that the sum of the plurality of discharge lamps does not become zero. A pump apparatus.
According to a second means, in the first means, the discharge lamp abnormality detection circuit includes a total current sensor for detecting a sum of currents flowing through the plurality of discharge lamps on a secondary side of the transformer. This is a discharge lamp device.
A third means is the second means, wherein the total current sensor is constituted by two total current sensors connected in series, and both ends of the series connected total current sensors are not grounded, and the series The discharge lamp device is characterized in that the middle of the connected total current sensors is grounded.
According to a fourth means, in any one of the first to third means, the discharge lamp is an external electrode type fluorescent lamp having a pair of electrodes outside the discharge vessel. This is a discharge lamp device.

  According to the present invention, there is no risk of a decrease in light output or dielectric breakdown as compared with a conventional one in which a lighting sensor is disposed in the vicinity of a discharge lamp to detect non-lighting of the discharge lamp, and individual differences among discharge lamps There is no need to add a circuit to prevent malfunction due to the influence of the routing, installation state, ambient temperature, etc. of the substrate pattern, and if any one of the plurality of discharge lamps connected in parallel is not lit, It is possible to reliably detect and perform a protection operation.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a circuit configuration of a discharge lamp device according to the present invention, FIG. 2 is a diagram showing a configuration of a rare gas fluorescent lamp, and FIG. 3 is a diagram showing a configuration of an EEFL lamp.
In FIG. 1, 1 is a DC power source, 2 is a high frequency generation circuit, 3 is a transformer, 4 is a discharge lamp, 5 is a current comparison transformer, 6 is a current sensor, 7 is an abnormality detection circuit, and the discharge lamp abnormality detection circuit is It comprises a current comparison transformer 5, a current sensor 6, an abnormality detection circuit 7, and the like.

As an example of the discharge lamp 4, an external electrode type rare gas fluorescent lamp as shown in FIG. 2 is used. This external electrode type rare gas fluorescent lamp 41 includes a straight glass tube 42 enclosing a rare gas therein, a pair of external electrodes 43 and 44 extending in the tube axis direction on the outer surface of the glass tube 42, and a glass tube 42. And a fluorescent material 45 applied to the inner surface of the substrate.
As another example of the discharge lamp 4, an EEFL lamp 46 as shown in FIG. 3 is used. The EEFL lamp 46 is not provided with an electrode inside the glass tube 47, but is provided at both ends of the outer surface of the glass tube 47 in which a fluorescent material 50 as a light emitter is applied on the inner surface and a discharge gas is filled into the discharge space as a discharge medium. The external electrodes 48 and 49 are formed.

  As shown in FIG. 1, the high frequency generator circuit 2 receives a DC voltage from the DC power source 1 and outputs a high frequency voltage. The push-pull inverter circuit, half-bridge inverter circuit, full-bridge inverter circuit, flyback It is composed of any circuit such as an inverter circuit.

  The transformer 3 boosts the high frequency voltage output from the high frequency generation circuit 2 input to the primary side, and outputs the high frequency high voltage from the secondary side. One end of the secondary side terminal of the transformer 3 is connected to one of the electrodes of the discharge lamp (1 to N) 4, and each opposing electrode of the discharge lamp (1 to N) 4 is a current input of the current comparison transformer 5. Each of the coils (1 to N) 51 is connected to the terminal A side.

  The current input coil (1 to N) 51 is wound around a common magnetic path of the magnetic body of the current comparison transformer 5 and is common when currents of the same magnitude are supplied in the same direction with the terminal A or the terminal B as a reference. The magnetic fluxes generated in the magnetic paths are configured to cancel each other and become zero. All terminals B of the current input coils (1 to N) 51 are short-circuited and connected to the other end of the secondary side terminal of the transformer 3 via the current sensor 6.

  A current sensor output signal is output from the current sensor 6 and input to the abnormality detection circuit 7. As the current sensor 6, a resistor, a capacitor, a coil, a current transformer, a photocoupler, or a combination of these is used.

  The magnetic flux detection coil 52 of the current comparison transformer 5 is wound around a common magnetic path with the current input coils (1 to N) 51, and detects a magnetic flux change generated in the common magnetic path. The induced electromotive force induced in the magnetic flux detection coil 52 is output as a current comparison transformer output signal and input to the abnormality detection circuit 7. The abnormality detection circuit 7 detects an abnormality of the discharge lamp (1 to N) 4 based on the lighting operation start signal, the current sensor output signal, and the current comparison transformer output signal, and outputs the abnormality occurrence signal to the high frequency generation circuit 2. .

  The high frequency generation circuit 2 is normally controlled to operate and stop according to the state of the lighting operation start signal, but when the abnormality is notified by the abnormality generation signal output from the abnormality detection circuit 7, the lighting operation start signal Regardless of the state, the high-frequency voltage output is immediately stopped.

FIG. 4 is a diagram showing a detailed circuit configuration of the abnormality detection circuit 7 shown in FIG.
In the figure, 71 is a smoothing circuit (1), 72 is a smoothing circuit (2), 73 is an overcurrent detection circuit, 74 is a no-load detection circuit, 75 is a current mismatch detection circuit, 76 is an OR circuit (1), Reference numeral 77 denotes a lighting impossibility detection circuit, and reference numeral 78 denotes an OR circuit (2). Other configurations correspond to the configurations of the same reference numerals shown in FIG.

  In the figure, the current sensor 6 outputs a current sensor output signal which is an analog signal, and the signal is input to the smoothing circuit (1) 71. The smoothing circuit (1) 71 outputs an analog signal obtained by smoothing the current sensor output signal, and the signal is input to the overcurrent detection circuit 73 and the no-load detection circuit 74. The overcurrent detection circuit 73 outputs an overcurrent detection signal which is a logic signal, and the signal is input to the OR circuit (2) 78. The overcurrent detection signal becomes true when the magnitude of the analog signal of the smoothing circuit (1) 71 exceeds the set value in the overcurrent detection circuit 73 and is held by itself.

  The no-load detection circuit 74 outputs a no-load detection signal that is a logic signal, and the signal is input to the OR circuit (1) 76. The no-load detection signal becomes true when the analog signal of the smoothing circuit (1) 71 falls below a set value in the no-load detection circuit 74.

  The current comparison transformer output signal detected by the magnetic flux detection coil 52 of the current comparison transformer 5 is input to the smoothing circuit (2) 72, and the smoothing circuit (2) 72 outputs an analog signal obtained by smoothing the current comparison transformer output signal. The analog signal is input to the current mismatch detection circuit 75. The current mismatch detection circuit 75 outputs a current mismatch detection signal that is a logic signal, and this signal is input to the OR circuit (1) 76. The current mismatch detection signal becomes true when the analog signal of the smoothing circuit (1) 71 exceeds the set value in the current mismatch detection circuit 75.

  The lighting failure detection circuit 77 outputs a lighting failure detection signal that is a logic signal when the time during which both the input A and the input B are true exceeds the set time, and the signal is input to the OR circuit (2) 78. The The OR circuit (2) 78 outputs an abnormality occurrence signal that is a logic signal.

Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a diagram showing a circuit configuration of the discharge lamp device according to the invention of the present embodiment.
In the figure, 8 is a step-up transformer (1), 9 is a step-up transformer (2), 10 is a current sensor (1), and 11 is a current sensor (2). Other configurations correspond to the configurations of the same reference numerals shown in FIG.

  The high frequency pulse voltage output from the high frequency generation circuit 2 is input in parallel to the primary side of the step-up transformer (1) 8 and the step-up transformer (2) 9 so as to have an opposite phase. The step-up transformer (1) 8 and the step-up transformer (2) 9 step up the high-frequency pulse voltage input to the primary side, and output a high-frequency high voltage having an opposite phase to the secondary side.

  The secondary HV terminal of the step-up transformer (1) 8 is connected to one of the electrodes of the discharge lamp (1 to N) 4, and the other electrode facing the discharge lamp (1 to N) 4 is connected to the current comparison transformer. The five current input coils (1 to N) 51 are respectively connected to the terminal A side.

  The current input coil (1 to N) 51 is wound around a common magnetic path of the magnetic body of the current comparison transformer 5 and is common when currents of the same magnitude are supplied in the same direction with the terminal A or the terminal B as a reference. The magnetic fluxes generated in the magnetic paths are configured to cancel each other and become zero. All terminals B of the current input coils (1 to N) 51 are short-circuited and connected to the secondary HV terminal of the step-up transformer (2) 9.

  The magnetic flux detection coil 52 of the current comparison transformer 5 is wound around a common magnetic path with the current input coils (1 to N) 51, and detects a magnetic flux change generated in the common magnetic path. The induced electromotive force induced in the magnetic flux detection coil 52 is output as a current comparison transformer output signal, and this signal is input to the abnormality detection circuit 7.

  The secondary side LV terminal of the step-up transformer (1) is connected to one end of the current sensor (1) 10, the other end of the current sensor (1) 10 is grounded, and the current sensor (1) from the current sensor (1) 10 is connected. ) The output signal is input to the abnormality detection circuit 7. The secondary LV terminal of the step-up transformer (2) is connected to one end of the current sensor (2) 11, the other end of the current sensor (2) 11 is grounded, and the current sensor from the current sensor (2) 11 is connected. (2) The output signal is input to the abnormality detection circuit 7. As the current sensor (1) 10 and the current sensor (2) 11, a resistor, a capacitor, a coil, a current transformer, a photocoupler, or the like, or a combination thereof is used.

  The abnormality detection circuit 7 detects an abnormality of the external electrode type discharge lamps (1 to N) 4 based on the lighting operation start signal, the current sensor (1) output signal, the current sensor (2) output signal, and the current comparison transformer output signal. It detects and outputs an abnormality occurrence signal to the high frequency generation circuit 2.

  The high frequency generation circuit 2 is normally controlled to operate and stop according to the state of the lighting operation start signal, but when the abnormality is notified by the abnormality generation signal output from the abnormality detection circuit 7, the lighting operation start signal Regardless of the state, the high-frequency voltage output is immediately stopped.

  The step-up transformer (1) 8 and the step-up transformer (2) 9 have a configuration in which the primary coils of the step-up transformer (1) and the step-up transformer (2) are connected in series in addition to the configuration shown in FIG. May be configured with one secondary coil divided into two.

FIG. 6 is a diagram showing a detailed circuit configuration of the abnormality detection circuit 7 shown in FIG.
In the same figure, the structure in the abnormality detection circuit 7 corresponds to the structure of the same symbol shown in FIG. The current sensor (1) 10 and the current sensor (2) 11 each output an output signal and an output signal of the current sensor (1), which are analog signals, and are input to the smoothing circuit (1) 71. The smoothing circuit (1) 71 outputs an analog signal obtained by smoothing the output signal of the current sensor (1) and the output signal of the current sensor (2), and the signal is input to the overcurrent detection circuit 73 and the no-load detection circuit 74. .

  The overcurrent detection circuit 73 outputs an overcurrent detection signal which is a logic signal, and the signal is input to the OR circuit (2) 78. The overcurrent detection signal becomes true when the magnitude of the analog signal of the smoothing circuit (1) 71 exceeds the set value in the overcurrent detection circuit 73 and is held by itself.

  The no-load detection circuit 74 outputs a no-load detection signal that is a logic signal, and this signal is input to the OR circuit (1) 76. The no-load detection signal becomes true when the analog signal of the smoothing circuit (1) 71 falls below a set value in the no-load detection circuit 74.

  The current comparison transformer output signal detected by the magnetic flux detection coil 52 of the current comparison transformer 5 is input to the smoothing circuit (2) 72. The smoothing circuit (2) 72 outputs an analog signal obtained by smoothing the current comparison transformer output signal, and the signal is input to the current mismatch detection circuit 75. The current mismatch detection circuit 75 outputs a current mismatch detection signal that is a logic signal, and this signal is input to the OR circuit (1) 76. The current mismatch detection signal becomes true when the analog signal of the smoothing circuit (2) 72 exceeds the set value in the current mismatch detection circuit 75.

  A lighting operation start signal that is a logic signal is input to the input A of the lighting failure detection circuit 77, and an output signal of the logical sum circuit (1) 76 is input to the input B of the lighting failure detection circuit 77. The lighting failure detection circuit 77 outputs a lighting failure detection signal that is a logical signal when the time during which both the input A and the input B are true exceeds the set time, and this signal is input to the OR circuit (2) 78. The OR circuit (2) 78 outputs an abnormality occurrence signal which is a logic signal.

Next, with reference to FIG. 7, a circuit operation when one discharge lamp during lighting operation in the discharge lamp device according to the invention of the present embodiment is not lit will be described.
FIG. 7 is a timing chart showing circuit operations in the circuits shown in FIGS. Here, all logic signals are represented by positive logic.

  First, at time point a, the lighting operation start signal becomes true, and the high frequency generation circuit 2 starts operating. Since the discharge lamp 4 is not lit at the time point a, the no-load detection signal and the output signal of the logical sum circuit (1) become true. At a time point b, the discharge lamp 4 starts to discharge after a slight delay in the start of discharge. At the same time, the no-load detection signal and the output signal of the logical sum circuit (1) become false.

  Next, assuming that one of the discharge lamps (1 to N) 4, for example, the discharge lamp (2) 4 is not lit at time c, the non-lighting discharge lamp (2) 4 has a current (IL2). Becomes difficult to flow, current balance is lost, and a pulse signal is generated in the current comparison transformer output signal. At the same time, the current mismatch detection signal and the output signal of the logical sum circuit (1) become true.

  The current sensor (1) output signal and the current sensor (2) output signal are reduced by a magnitude of 1 / N, but when the number N of the discharge lamps (1 to N) 4 is large, the change of these signals is small. Therefore, the no-load detection signal remains false. Usually, it is difficult to detect a failure when one of the plurality of discharge lamps is damaged. For example, when N = 10, it is necessary to detect the failure with an accuracy of 1/10. When N = 20, it is necessary to detect with an accuracy of 1/20, but the lamp current variation is ± 10%. In some cases, a failure may not be detected.

  Finally, the time when the lighting operation start signal and the logical sum circuit (1) output signal (input A and input B of the lighting failure detection circuit 77) are true exceeds the reference time inside the lighting failure detection circuit 77 at the time point d, The lighting impossible detection signal becomes true. At the same time, the abnormality occurrence signal becomes true, the operation of the high frequency generation circuit 2 is stopped, and all the discharge lamps (1 to N) 4 are turned off.

Next, the circuit operation when all the discharge lamps in the lighting operation in the discharge lamp device according to the invention of the present embodiment are not lit will be described with reference to FIG.
FIG. 8 is a timing chart showing circuit operations in the circuits shown in FIGS. Here, all logic signals are represented by positive logic.

  The operation at time point a and time point b is the same as in FIG. If all the discharge lamps (1 to N) 4 are not lit at time c, the output signal of the current sensor (1) and the output signal of the current sensor (2) become zero, the output signal of the OR circuit (1) and The no-load detection signal becomes true. The current comparison transformer output signal is not output at all because the current flowing through each discharge lamp (1 to N) 4 is balanced to zero, and the current mismatch detection signal remains false.

  Finally, the time when the lighting operation start signal and the logical sum circuit (1) output signal (input A and input B of the lighting failure detection circuit 77) are true exceeds the reference time in the lighting failure detection circuit at the time point d, and the lighting is performed. The impossibility detection signal becomes true. At the same time, the abnormality occurrence signal becomes true, and the operation of the high frequency generation circuit 2 is stopped.

  Thus, when some of the discharge lamps (1 to N) 4 are not lit, a signal is generated as a current comparison transformer output signal, but all the discharge lamps (1 to N) 4 are not lit simultaneously. In this case, no signal is generated in the current comparison transformer output signal. Therefore, partial non-lighting detection by the current comparison transformer 5 and total non-lighting detection by the current sensors (1) 10 and (2) and (12) must be performed simultaneously.

Next, the circuit operation when one of the discharge lamps in the lighting operation is short-circuited in the discharge lamp device according to the invention of the present embodiment will be described with reference to FIG.
FIG. 9 is a timing chart showing circuit operations in the circuits shown in FIGS. Here, all logic signals are represented by positive logic.

  The operation at time point a and time point b is the same as in FIG. If the discharge lamp (1) 4 of the discharge lamps (1 to N) 4 is short-circuited at a time point c and a large short-circuit current (IL1) flows, the current sensor (1) 10 and the current sensor (2) 11 are large. The output signal of the current sensor (1) and the output signal of the current sensor (2) are output, and the overcurrent detection signal output from the overcurrent detection circuit 73 becomes true. As a result, the abnormality occurrence signal output from the OR circuit (2) 78 becomes true, and the high frequency generation circuit 2 immediately stops its operation.

  Further, even when any of the high-voltage terminals has a ground fault, since the ground fault current is detected by either the current sensor (1) 10 or the current sensor (2) 11, the operation of the high-frequency generation circuit 2 is immediately stopped. be able to.

FIG. 10 is a diagram showing a more detailed circuit configuration of the abnormality detection circuit 7, the current sensor (1) 10, and the current sensor (2) 11 shown in FIG.
As shown in the figure, the current sensor (1) 10 is composed of a resistor R1, and the voltage generated by the current flowing through the resistor R1 becomes an output signal of the current sensor (1). Further, the current sensor (2) 11 is constituted by a resistor R2, and a voltage generated by the current flowing through the resistor R2 becomes an output signal of the current sensor (2).

  In the smoothing circuit (1) 71, the current sensor (1) output signal and the current sensor (2) output signal are respectively input to the anode terminals of the diodes D1 and D2. The cathode terminals of the diodes D1 and D2 are connected to each other, and are further grounded through a capacitor C1 and a resistor R3 connected in parallel. The output signal of the current sensor (1) and the output signal of the current sensor (2) are rectified and synthesized via the diodes D1 and D2, smoothed by the capacitor C1 and the resistor R3, and become an output signal of the smoothing circuit (1) 71.

  In the overcurrent detection circuit 73, the output signal of the smoothing circuit (1) 71 is input to the + terminal of the comparator 1, and the reference voltage Vref1 is input to the − terminal. The output signal of the comparator 1 is connected to the S terminal of the latch circuit, the R terminal of the latch circuit is connected to the reset circuit, and an overcurrent detection signal is output from the Q terminal of the latch circuit. When the High signal is input to the S terminal, the latch circuit sets the overcurrent detection signal to High, and maintains that state until the High signal is input to the R terminal. The reset circuit outputs a pulse signal of a High signal when the power is turned on or from an external operation, etc., resets the latch circuit, and sets the overcurrent detection signal to Low.

  In the no-load detection circuit 74, the output signal of the smoothing circuit (1) 71 is input to the negative terminal of the comparator 2, and the reference voltage Vref2 is input to the positive terminal. The comparator 2 outputs a no-load detection signal. The comparator 2 compares the output signal of the smoothing circuit (1) 71 with the reference voltage Vref2, and when the output signal of the smoothing circuit (1) 71 is small, the no-load detection signal is set to High.

  In the smoothing circuit (2) 72, the current comparison transformer output signal is input to both ends of the resistor R4, one end of the resistor R4 is connected to the anode terminal of the diode D3, and the other end is grounded. The cathode terminal of the diode D3 is grounded via a capacitor C2 and a resistor R5 connected in parallel. The resistor R4 constitutes an integration circuit together with the magnetic flux detection coil of the current comparison transformer 5, and converts the magnitude of the magnetic flux change into a voltage. The voltage of the resistor R4 is rectified and smoothed by the diode D3, the capacitor C2, and the resistor R5, and becomes an output signal of the smoothing circuit (2) 72.

  In the current mismatch detection circuit 75, the output signal of the smoothing circuit (2) 72 is input to the + terminal of the comparator 3, and the reference voltage Vref3 is input to the-terminal. A current mismatch detection signal is output from the comparator 3. The comparator 3 compares the output signal of the smoothing circuit (2) 72 with the reference voltage Vref3, and sets the current mismatch detection signal to High when the output signal of the smoothing circuit (2) 72 is large.

  The OR circuit (1) 76 receives the no-load detection signal and the current mismatch detection signal, and outputs a High signal when any of these input signals becomes High.

  In the lighting failure detection circuit 77, a lighting operation start signal is input to the A terminal, and an output signal from the OR circuit (1) 76 is input to the B terminal. The A terminal is connected to one input terminal of the AND circuit, and the B terminal is connected to the other input terminal of the AND circuit. The output terminal of the AND circuit is connected to the buffer via a diode D4 and a resistor R6 connected in parallel. The anode terminal of the diode D4 is located on the input side of the buffer. A non-lighting detection signal is output from the buffer. When both the A terminal and the B terminal become High, the output terminal of the AND circuit becomes High, and the capacitor C3 is charged through the resistor R6. When the voltage of the capacitor C3 exceeds the buffer threshold, the output signal of the buffer becomes High, and the lighting failure detection signal becomes High. By changing the time constants of the resistor R6 and the capacitor C3, it is possible to adjust the set time at which it is determined that lighting is impossible. When either the A terminal or the B terminal becomes Low, the output terminal of the AND circuit becomes Low, and the capacitor C3 is quickly discharged via the diode D4.

  The OR circuit (2) 78 receives the overcurrent detection signal and the lighting failure detection signal, and outputs a High signal when any of these input signals becomes High, and the signal becomes an abnormality occurrence signal.

FIG. 11 is a diagram illustrating an example of the configuration of the current comparison transformer 5 illustrated in FIGS. 1, 4 to 6, and 10.
The magnetic material used for the magnetic path of the current comparison transformer 5 is a ferrite core or the like, and its shape is a toroidal type, E type, U type, I type, or the like. The current input coil (1) 51 to current input coil (4) 51 are wound around a common magnetic path, and the turn ratio of each current input coil (1) 51 to (4) 51 is 1: 1: 1: 3. It is.

  When the current input coils (1) 51 to (3) 51 cause the currents IL1 to IL3 flowing through the current input coils (1) 51 to (3) 51 to flow in the directions of the arrows, the current input coils (1) 51 to (3) 51 generate a magnetic flux in the direction of the arrows of the magnetic flux φ. appear. Moreover, when the current IL4 flowing through the current input coil (4) 51 flows in the direction of the arrow, the current input coil (4) 51 generates a magnetic flux in the direction opposite to the arrow of the magnetic flux φ. Since the magnitude of the magnetic flux per unit current of the current input coil (4) is three times that of the current input coils (1) 51 to (3) 51, the current input coils (1) 51 to (4) 51 If the magnitude of the flowing current is the same, the magnetic flux generated in the magnetic path cancels and becomes zero.

  The magnetic flux detection coil 52 is wound around a common magnetic path with the current input coils (1) 51 to (4) 51. When a magnetic flux change occurs in the magnetic path, an induced electromotive force is generated, and this is detected. It is possible to know the mismatch of the currents flowing through the current input coils (1) 51 to (4) 51.

12 shows the configuration of the number of turns of the four current input coils (1) 51 to (4) 51 of the current comparison transformer 5, and the magnitudes of currents IL1 to IL4 flowing through the current input coils (1) 51 to (4) 51. And a table showing the sum of magnetomotive forces.
Here, the sign of the number of turns of the current input coil represents the direction of the magnetic flux. The magnitude of the current flowing through the current input coil is 1 or 0. When the current flowing through the current input coil is 0, this corresponds to the fact that the discharge lamp connected to the current input coil is not lit. The magnetomotive force is the current flowing in the current input coil × the number of turns of the current input coil. The magnitude obtained by dividing the total magnetomotive force of each of the current input coils (1) 51 to (4) 51 by the magnetic resistance of the current comparison transformer 5 corresponds to the magnetic flux φ.

  Example 1 shows a case where the turns ratio of the current input coils (1) 51 to (4) 51 is 2: 2: 2: −6. In this case, the total magnetomotive force is 0. This is only when all of the currents IL1 to IL4 of the current input coils (1) 51 to (4) 51 become 1 or 0 as in No16. That is, when some of the discharge lamps are not lit, a change in magnetic flux in the magnetic path occurs, and the non-lighting can be detected by the induced electromotive force generated in the magnetic flux detection coil 52.

  Example 2 shows a case where the turns ratio of the current input coils (1) 51 to (4) 51 is 2: -2: 2: -2. In this case, the total magnetomotive force becomes zero. Not only when all of the currents IL1 to IL4 of the current input coils (1) 51 to (4) 51 become 1 or 0 as in No1 and No16, but also when No4, No7, etc., become 0. Therefore, it is impossible to detect all combinations in which some discharge lamps are not lit. In order to avoid the problem as in the second example, it is preferable that a plurality of current input coils except for all have no combination in which the sum of the number of turns of the current input coils is zero.

FIG. 13 is a diagram illustrating another example of the configuration of the current comparison transformer 5 illustrated in FIGS. 1, 4 to 6, and 10.
The magnetic material used for the magnetic path of the current comparison transformer 5 is a ferrite core or the like, and its shape is a toroidal type, E type, U type, I type, or the like. The current input coils (1) 51 to (6) 51 are wound around a common magnetic path, and the turn ratio of the current input coils (1) 51 to (6) 51 is 2: 2: 3: 3: 4: 4.

  When the current input coils (1) 51, (3) 51, (5) 51 pass a current in the direction of the arrow, the current input coils (1) 51, (3) 51, (5) 51 generate a magnetic flux in the forward direction of the arrow of the magnetic flux φ. 4) 51 and (6) 51 generate a magnetic flux in the direction opposite to the arrow of the magnetic flux φ when a current flows in the direction of the arrow. The current IL5 flowing through the current input coil (5) 51 is connected so that a combined current of the current IL1 flowing through the current input coil (1) 51 and the current IL2 flowing through the current input coil (2) 51 flows. 6) The current IL6 flowing in 51 is connected so that a combined current of the current IL3 flowing in the current input coil (3) 51 and the current IL4 flowing in the current input coil (4) 51 flows.

  In the structure of the current comparison transformer 5, the current IL1 flowing through the current input coil (1) 51 = the current IL2 flowing through the current input coil (2) 51, the current IL3 flowing through the current input coil (3) 51 = the current input coil (4 ) In the case of current IL4 flowing through 51 and IL1 + IL2 + IL3 + IL4, that is, when IL1 = IL2 = IL3 = IL4, the magnetic fluxes in the magnetic path cancel each other and become zero.

  The magnetic flux detection coil 52 is wound around a magnetic path common to the current input coils (1) 51 to (6) 51. When a magnetic flux change occurs in the magnetic path, an induced electromotive force is generated, and current is detected by detecting this. It is possible to know the mismatch of the currents flowing through the input coils (1) 51 to (6) 51.

  14 shows the configuration of the number of turns of each current input coil (1) 51 to (6) 51 and the current input coils (1) 51 to 51 for the current input coils (1) 51 to (6) 51 shown in FIG. (6) It is the table | surface shown about the electric current IL1-IL6 which flows into 51, and the sum total of a magnetomotive force. Here, the sign of the number of turns of the current input coils (1) 51 to (6) 51 represents the direction of the magnetic flux, and the magnitudes of the currents IL1 to IL4 of the current input coils (1) 51 to (4) 51 are 1 or 0. And When the current flowing through the current input coil is 0, this corresponds to the lamp connected to the current input coil being unlit. The magnetomotive force is the current flowing through the current input coil × the number of turns of the current input coil. The magnitude obtained by dividing the total magnetomotive force of each of the current input coils (1) 51 to (6) 51 by the magnetic resistance of the current comparison transformer 5 corresponds to the magnetic flux φ.

  The total magnetomotive force is 0 only when all of the currents IL1 to IL4 flowing through the current input coils (1) 51 to (4) 51 are 1 or 0 as in No1 and No16. That is, when some of the lamps are not lit, magnetic flux changes in the magnetic path, and the non-lighting can be detected by the induced electromotive force generated in the magnetic flux detection coil 52.

It is a figure which shows the circuit structure of the lamp device which concerns on invention of 1st Embodiment. It is a figure which shows the structure of a noble gas fluorescent lamp. It is a figure which shows the structure of an EEFL lamp. It is a figure which shows the detailed circuit structure of the abnormality detection circuit 7 shown in FIG. It is a figure which shows the circuit structure of the lamp device which concerns on invention of 2nd Embodiment. It is a figure which shows the detailed circuit structure of the abnormality detection circuit 7 shown in FIG. 7 is a timing chart showing circuit operations in the circuits shown in FIGS. 5 and 6. 7 is a timing chart showing circuit operations in the circuits shown in FIGS. 5 and 6. 7 is a timing chart showing circuit operations in the circuits shown in FIGS. 5 and 6. It is a figure which shows the more detailed circuit structure of the abnormality detection circuit 7, current sensor (1) 10, and current sensor (2) 11 which were shown in FIG. It is a figure which shows an example of a structure of the current comparison transformer 5 shown in FIG.1, FIG.4-FIG.6, and FIG. The configuration of the number of turns of the four current input coils (1) 51 to (4) 51 of the current comparison transformer, the magnitudes IL1 to IL4 of the current flowing through the current input coils (1) 51 to (4) 51, and the magnetomotive force It is the table | surface shown about the total. FIG. 11 is a diagram illustrating another example of the configuration of the current comparison transformer 5 illustrated in FIGS. 1, 4 to 6, and 10. For the current input coils (1) 51 to (6) 51 shown in FIG. 13, the number of turns of each current input coil (1) 51 to (6) 51, and each current input coil (1) 51 to (6) 51 It is the table | surface shown about the sum total of the electric current IL1-IL6 and magnetomotive force which flow into.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2 High frequency generating circuit 3 Transformer 4 Outdoor lamp (1-N)
41 External electrode type rare gas fluorescent lamp 42 Glass tube 43, 44 External electrode 45 Fluorescent material 46 EEFL lamp 47 Glass tube 48, 49 External electrode 50 Fluorescent material 5 Current comparison transformer 51 Current input coil (1 to N)
52 Magnetic flux detection coil 6 Current sensor 7 Abnormality detection circuit 71 Smoothing circuit (1)
72 Smoothing circuit (2)
73 Overcurrent detection circuit 74 No-load detection circuit 75 Current mismatch detection circuit 76 OR circuit (1)
77 Non-lighting detection circuit 78 OR circuit (2)
8 Step-up transformer (1)
9 Step-up transformer (2)
10 Current sensor (1)
11 Current sensor (2)

Claims (4)

In a discharge lamp device comprising a high frequency generation circuit, the transformer in which the output side of the high frequency generation circuit is connected to the primary side of the transformer, and a plurality of discharge lamps connected in parallel to the secondary side of the transformer,
When a plurality of windings connected in series with each of the plurality of discharge lamps and a magnetic flux detection winding are wound around a magnetic body, and when all the discharge lamps are normally lit, the magnetic flux detection winding It is detected that the sum of magnetic fluxes generated in each of the plurality of windings becomes zero, and when at least one discharge lamp becomes abnormal, the sum of magnetic fluxes generated in each of the plurality of windings is zero. A discharge lamp device comprising: a discharge lamp abnormality detection circuit that detects that at least one of the plurality of discharge lamps has become abnormal by detecting that the failure has not occurred.   2. The discharge lamp device according to claim 1, wherein the discharge lamp abnormality detection circuit includes a total current sensor that detects a sum of currents flowing through the plurality of discharge lamps on a secondary side of the transformer.   The summed current sensor is composed of two summed current sensors connected in series. Both ends of the summed current sensor connected in series are not grounded, and the middle of the summed current sensors connected in series is grounded. The discharge lamp device according to claim 2, wherein The discharge lamp device according to any one of claims 1 to 3, wherein the discharge lamp is an external electrode type fluorescent lamp provided with a pair of electrodes outside a discharge vessel.

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