JP2006236876A - Lamp lighting circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably light lamps while suppressing dispersion of luminance of the lamps even when the number of lamps is increased. <P>SOLUTION: This lamp lighting circuit includes multiple closed loops wherein a predetermined number of lamps and the secondary windings of the predetermined number of transformers are connected serially. At least one of the primary windings of the transformers employed for each closed loop is connected to the primary winding of the transformer employed for another closed loop serially. By using such a structure, current of the lamps included in the closed loop is made uniform, and also current is made uniform even between the closed loops by connecting the primary windings of the transformers serially. According to this application, with regard to serial connection of the primary windings of the transformers, even if the number of transformers is limited, current uniformity can be propagated to the entirety by subjecting closed loops to catenation consecutively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lamp (for example, discharge tube) lighting circuit.

  For example, a discharge tube such as a cold cathode fluorescent tube has been conventionally used for a backlight of a liquid crystal display device. In recent years, the number of discharge tubes used for backlights has increased due to the increase in the size of liquid crystal display devices. However, it is required to make the current flowing through them uniform and to make the luminance uniform.

FIG. 1 shows a lighting circuit disclosed in Japanese Utility Model Laid-Open No. 59-187097. The lighting circuit shown in FIG. 1 includes an inverter V101, transformers T101 and T102, discharge tubes LP101 and LP102, and capacitors C101, C102, and C103. The inverter V101 is connected to terminals P1 and P2 of the primary winding of the transformer T101 and terminals P1 and P2 of the primary winding of the transformer T102. Note that the primary winding terminal P1 and the secondary winding terminal S1 of the transformer T101 are connected via a capacitor C102, and the primary winding terminal P1 and the secondary winding terminal S1 of the transformer T102 are both connected to the capacitor C103. Connected through. Further, the first terminal of the discharge tube LP101 is connected to the terminal S1 of the secondary winding of the transformer T101, and the second terminal of the discharge tube LP101 is connected to the terminal S1 of the secondary winding of the transformer T102. Has been. The first terminal of the discharge tube LP102 is connected to the terminal S2 of the secondary winding of the transformer T101, and the second terminal of the discharge tube LP102 is the terminal of the secondary winding of the transformer T102 via the capacitor C101. Connected to S2. Thus, the discharge tubes LP101 and LP102 are floating differential drive in which the left and right poles are opposite in polarity. However, a capacitor is connected to the secondary windings of the transformers T101 and T102, and there is a problem that the current balance of both the discharge tubes LP101 and LP102 is shifted by the capacity of the capacitor, resulting in a difference in the luminance of the discharge tubes. . Further, no consideration has been given as to what configuration is preferable when the number of discharge tubes is three or more.
Japanese Utility Model Publication No.59-187097

  Therefore, an object of the present invention is to provide a technique for stably lighting a lamp while suppressing variations in lamp brightness even when the number of lamps increases.

  The lamp lighting circuit according to the first aspect of the present invention has a plurality of closed loops in which a predetermined number of lamps and secondary windings of the predetermined number of transformers are connected in series. At least one of the primary windings of the transformer used in each closed loop is connected in series with the primary winding of the transformer used in the other closed loop. By adopting such a configuration, the current of the lamp included in the closed loop is made uniform, and the current can be made uniform between the closed loops by connecting the primary windings of the transformer in series. According to the present invention, even when the number of transformers is limited for the series connection of the primary windings of the transformer, the closed loops can be chained one after the other and the current uniformity can be propagated throughout.

  The lamp lighting circuit according to the second aspect of the present invention has a plurality of closed loops in which a predetermined number of lamps and secondary windings of the predetermined number of transformers are connected in series. All of the primary windings of the transformer used in each closed loop are connected in series with the primary windings of the transformers used in different closed loops. In this way, the coupling between the closed loops becomes strong, and the current uniformity is easily propagated throughout.

  Note that the predetermined number described above may be two. When the predetermined number is 2, the closed loops are connected so as to go around in a daisy chain.

  The lamp lighting circuit according to the third aspect of the present invention includes two lamps and secondary windings of two transformers connected in series so that the secondary windings of the lamp and the transformer are alternately arranged. A first closed loop, two lamps and two transformer secondary windings connected in series such that the lamp and transformer secondary windings alternate, and two lamps And a secondary winding of the two transformers and a third closed loop in which the lamp and the secondary winding of the transformer are alternately connected in series. The primary winding of the first transformer used in the first closed loop and the primary winding of any of the transformers used in the second closed loop are connected in series, and the second winding used in the first closed loop. The transformer primary winding and the primary winding of any of the transformers used in the third closed loop are connected in series. Thus, since the closed loop is chained in a daisy chain, the current uniformity is propagated along the chain.

  The lamp lighting circuit according to the fourth aspect of the present invention has a plurality of closed loops in which a first predetermined number of lamps and secondary windings of a first predetermined number of transformers are connected in series. And among the transformers used in the plurality of closed loops, the primary windings of the second predetermined number of transformers used in different closed loops are connected in series, and the secondary windings of the second predetermined number of transformers are At least one primary winding of another transformer used in a group of closed loops constituting a part is connected in series with a primary winding of a transformer used in a closed loop other than the closed loop group. Even if such a configuration is adopted, the current of the lamp included in the closed loop is made uniform.

  The lamp lighting circuit according to the fifth aspect of the present invention has a plurality of closed loops in which a first predetermined number of lamps and secondary windings of a first predetermined number of transformers are connected in series. The transformers used in the plurality of closed loops are grouped every second predetermined number, and the primary windings of the transformers in the group are connected in series, and the secondary windings of the transformers in the group The other transformers used in the closed loop that constitutes a part thereof belong to other groups. The coupling between the closed loops becomes stronger and the accuracy of the current uniformity becomes higher.

  A lamp lighting circuit according to a sixth aspect of the present invention is a lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to the lamp, and at least two primary windings. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are coupled via a transformer, and at least one of the secondary side closed loops is coupled to at least two other secondary side closed loops via the primary side closed loop. .

  In the lamp lighting circuit according to the sixth aspect of the present invention, at least one of the secondary side closed loops may be coupled to one other secondary side closed loop through the primary side closed loop.

  A lamp lighting circuit according to a seventh aspect of the present invention is a lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to the lamp, and at least two primary windings. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are coupled via a transformer, and all of the secondary side closed loops are connected to all other secondary loops via the primary side closed loop or the primary side closed loop and other secondary side closed loops. Combined with the secondary closed loop.

  In the lamp lighting circuit according to the seventh aspect of the present invention, the total number of transformers may be less than the product of the total number of primary closed loops and the total number of secondary closed loops.

  A lamp lighting circuit according to an eighth aspect of the present invention is a lamp lighting circuit including a plurality of transformers each having a primary winding connected to a power source and a secondary winding connected to the lamp, wherein the primary winding has at least two primary windings. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are coupled via a transformer, and at least one of the primary side closed loops is coupled to at least two other primary side closed loops via the secondary side closed loop.

  In the lamp lighting circuit according to the eighth aspect of the present invention, at least one of the primary side closed loops may be coupled to one other primary side closed loop through the primary side closed loop.

  A lamp lighting circuit according to a ninth aspect of the present invention is a lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to the lamp, and at least two primary windings. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are coupled via a transformer, and all of the primary side closed loops are connected to the secondary side closed loop or the secondary side closed loop and other primary side closed loops to all other primary sides. Combined with a closed loop.

  In the lamp lighting circuit according to the ninth aspect of the present invention, the total number of transformers may be smaller than the product of the total number of primary side closed loops and the total number of secondary closed loops.

  A lamp lighting circuit according to a tenth aspect of the present invention is a lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to the lamp, and at least two primary windings are provided. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are coupled via a transformer, and at least one of the secondary side closed loops is coupled to at least two other secondary side closed loops via the primary side closed loop and the primary side closed loop. At least one of the side closed loops is coupled to at least two other primary side closed loops via a secondary side closed loop.

  A lamp lighting circuit according to an eleventh aspect of the present invention is a lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to the lamp, and at least two primary windings are provided. A plurality of primary side closed loops arranged in series and a plurality of secondary side closed loops arranged with at least two secondary windings arranged in series. The primary side closed loop and the secondary side closed loop are alternately coupled in a chain via a transformer, and include at least three alternate coupling portions of the primary side closed loop and the secondary side closed loop.

  There are a plurality of circuits for realizing the above configuration, and specific examples are shown below, but the present invention is not limited to these.

  According to the present invention, even when the number of lamps increases, the lamp can be stably lit while suppressing variations in lamp luminance.

1. Embodiment 1
FIG. 2 shows a discharge tube lighting circuit 10 according to the first embodiment. The discharge tube lighting circuit 10 includes transformers T1 to T20 and discharge tubes LP1 to LP20 such as cold cathode fluorescent tubes. A terminal P1 of the primary winding of the transformer T1 is connected to a terminal P2 of the primary winding of the transformer T19 and a voltage detection terminal S5. A terminal P1 of the primary winding of the transformer T19 is connected to a first terminal of an inverter circuit (not shown) via an INV + terminal. A terminal P2 of the primary winding of the transformer T1 is connected to a second terminal of an inverter circuit (not shown) via an INV− terminal. That is, the primary windings of the transformers T1 and T19 are connected in series. The terminal S1 of the secondary winding of the transformer T1 is connected to one end of the discharge tube LP1, and the other end of the discharge tube LP1 is connected to the terminal S1 of the secondary winding of the transformer T2. Further, the terminal S2 of the secondary winding of the transformer T2 is connected to one end of the discharge tube LP2, and the other end of the discharge tube LP2 is connected to the terminal S2 of the secondary winding of the transformer T1. That is, the secondary windings of the transformers T1 and T2 and the discharge tubes LP1 and LP2 form a closed loop. Further, the terminal P1 of the primary winding of the transformer T2 is connected to the second terminal of the inverter circuit (not shown) via the INV− terminal, and the terminal P2 of the primary winding of the transformer T2 is connected to the voltage detection terminal S6. It is connected to the terminal P1 of the primary winding of the transformer T4. A terminal P2 of the primary winding of the transformer T4 is connected to the INV + terminal. That is, the primary windings of the transformer T2 and the transformer T4 are connected in series. Thus, when a voltage having a polarity of + − is applied to both ends of the discharge tube LP1 from the left, a voltage having a polarity of − + is applied to both ends of the discharge tube LP2. As described above, the discharge tubes LP1 and LP2 included in one closed loop are differentially driven.

  A terminal P1 of the primary winding of the transformer T3 is connected to a first terminal of an inverter circuit (not shown) via an INV + terminal. The terminal P2 of the primary winding of the transformer T3 is connected to the voltage detection terminal S1 and the terminal P1 of the primary winding of the transformer T5. A terminal P2 of the primary winding of the transformer T5 is connected to the INV− terminal. That is, the primary windings of the transformers T3 and T5 are connected in series. The terminal S1 of the secondary winding of the transformer T3 is connected to one end of the discharge tube LP3, and the other end of the discharge tube LP3 is connected to the terminal S1 of the secondary winding of the transformer T4. Further, the secondary winding terminal S2 of the transformer T4 is connected to one end of the discharge tube LP4, and the other end of the discharge tube LP4 is connected to the secondary winding terminal S2 of the transformer T3. That is, the secondary windings of the transformers T3 and T4 and the discharge tubes LP3 and LP4 constitute a closed loop. The discharge tubes LP3 and LP4 included in the closed loop are also driven by differential floating.

  Further, the terminal S1 of the secondary winding of the transformer T5 is connected to one end of the discharge tube LP5, and the other end of the discharge tube LP5 is connected to the terminal S1 of the secondary winding of the transformer T6. Further, the secondary winding terminal S2 of the transformer T6 is connected to one end of the discharge tube LP6, and the other end of the discharge tube LP6 is connected to the secondary winding terminal S2 of the transformer T5. As described above, the secondary windings of the transformers T5 and T6 and the discharge tubes LP5 and LP6 form a closed loop. The discharge tubes LP5 and LP6 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T6 is connected to the terminal INV-, and the terminal P2 of the primary winding of the transformer T6 is connected to the voltage detection terminal S7 and the terminal P1 of the primary winding of the transformer T8. . A terminal P2 of the primary winding of the transformer T8 is connected to the INV + terminal. Thus, the primary windings of the transformer T6 and the transformer T8 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T8 is connected to one end of the discharge tube LP7, and the other end of the discharge tube LP7 is connected to the terminal S1 of the secondary winding of the transformer T7. Further, the terminal S2 of the secondary winding of the transformer T7 is connected to one end of the discharge tube LP8, and the other end of the discharge tube LP8 is connected to the terminal S2 of the secondary winding of the transformer T8. Thus, the secondary windings of the transformers T7 and T8 and the discharge tubes LP7 and LP8 also form a closed loop. The discharge tubes LP7 and LP8 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T7 is connected to the terminal INV +, and the terminal P2 of the primary winding of the transformer T7 is connected to the voltage detection terminal S2 and the terminal P1 of the primary winding of the transformer T9. A terminal P2 of the primary winding of the transformer T9 is connected to the terminal INV-. Thus, the primary windings of the transformer T7 and the transformer T9 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T9 is connected to one end of the discharge tube LP9, and the other end of the discharge tube LP9 is connected to the terminal S1 of the secondary winding of the transformer T10. Furthermore, the secondary winding terminal S2 of the transformer T10 is connected to one end of the discharge tube LP10, and the other end of the discharge tube LP10 is connected to the secondary winding terminal S2 of the transformer T9. Thus, the secondary windings of the transformers T9 and T10 and the discharge tubes LP9 and LP10 form a closed loop. The discharge tubes LP9 and LP10 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T10 is connected to the terminal INV-, and the terminal P2 of the primary winding of the transformer T10 is connected to the voltage detection terminal S8 and the terminal P1 of the primary winding of the transformer T12. . A terminal P2 of the primary winding of the transformer T12 is connected to the INV + terminal. Thus, the primary windings of the transformer T10 and the transformer T12 are connected in series.

  Furthermore, the terminal S1 of the secondary winding of the transformer T12 is connected to one end of the discharge tube LP11, and the other end of the discharge tube LP11 is connected to the terminal S1 of the secondary winding of the transformer T11. Further, the terminal S2 of the secondary winding of the transformer T11 is connected to one end of the discharge tube LP12, and the other end of the discharge tube LP12 is connected to the terminal S2 of the secondary winding of the transformer T12. Thus, the secondary windings of the transformers T11 and T12 and the discharge tubes LP11 and LP12 constitute a closed loop. The discharge tubes LP11 and LP12 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T11 is connected to the terminal INV +, and the terminal P2 of the primary winding of the transformer T11 is connected to the voltage detection terminal S3 and the terminal P1 of the primary winding of the transformer T13. A terminal P2 of the primary winding of the transformer T13 is connected to the terminal INV−. Thus, the primary windings of the transformer T11 and the transformer T13 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T13 is connected to one end of the discharge tube LP13, and the other end of the discharge tube LP13 is connected to the terminal S1 of the secondary winding of the transformer T14. Furthermore, the secondary winding terminal S2 of the transformer T14 is connected to one end of the discharge tube LP14, and the other end of the discharge tube LP14 is connected to the secondary winding terminal S2 of the transformer T13. As described above, the secondary windings of the transformers T13 and T14 and the discharge tubes LP13 and LP14 form a closed loop. The discharge tubes LP13 and LP14 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T14 is connected to the terminal INV-, and the terminal P2 of the primary winding of the transformer T14 is connected to the voltage detection terminal S9 and the terminal P1 of the primary winding of the transformer T16. . A terminal P2 of the primary winding of the transformer T16 is connected to the INV + terminal. Thus, the primary windings of the transformer T14 and the transformer T16 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T16 is connected to one end of the discharge tube LP15, and the other end of the discharge tube LP15 is connected to the terminal S1 of the secondary winding of the transformer T15. Furthermore, the secondary winding terminal S2 of the transformer T15 is connected to one end of the discharge tube LP16, and the other end of the discharge tube LP16 is connected to the secondary winding terminal S2 of the transformer T16. As described above, the secondary windings of the transformers T15 and T16 and the discharge tubes LP15 and LP16 form a closed loop. The discharge tubes LP15 and LP16 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T15 is connected to the terminal INV +, and the terminal P2 of the primary winding of the transformer T15 is connected to the voltage detection terminal S4 and the terminal P1 of the primary winding of the transformer T17. A terminal P2 of the primary winding of the transformer T17 is connected to the terminal INV-. Thus, the primary windings of the transformer T15 and the transformer T17 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T17 is connected to one end of the discharge tube LP17, and the other end of the discharge tube LP17 is connected to the terminal S1 of the secondary winding of the transformer T18. Further, the secondary winding terminal S2 of the transformer T18 is connected to one end of the discharge tube LP18, and the other end of the discharge tube LP18 is connected to the secondary winding terminal S2 of the transformer T17. As described above, the secondary windings of the transformers T17 and T18 and the discharge tubes LP17 and LP18 form a closed loop. The discharge tubes LP17 and LP18 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T18 is connected to the terminal INV-, and the terminal P2 of the primary winding of the transformer T18 is connected to the voltage detection terminal S10 and the terminal P1 of the primary winding of the transformer T20. . A terminal P2 of the primary winding of the transformer T20 is connected to the INV + terminal. Thus, the primary windings of the transformer T18 and the transformer T20 are connected in series.

  Further, the terminal S1 of the secondary winding of the transformer T20 is connected to one end of the discharge tube LP19, and the other end of the discharge tube LP19 is connected to the terminal S1 of the secondary winding of the transformer T19. Further, the secondary winding terminal S2 of the transformer T19 is connected to one end of the discharge tube LP20, and the other end of the discharge tube LP20 is connected to the secondary winding terminal S2 of the transformer T20. As described above, the secondary windings of the transformers T19 and T20 and the discharge tubes LP19 and LP20 form a closed loop. The discharge tubes LP19 and LP20 included in the closed loop are also driven by differential floating.

  As described above, the current is equalized in each closed loop, and the current in the closed loop including the secondary windings of the transformer T2 and the transformer T4 is also equalized by the series connection of the primary windings of the transformer T2 and the transformer T4. . Similarly, the series connection of the primary windings of the transformer T3 and the transformer T5 also equalizes the closed loop current including the secondary windings of the transformer T3 and the transformer T5. Furthermore, the series connection of the primary windings of the transformer T6 and the transformer T8 makes the closed loop current including the secondary windings of the transformer T6 and the transformer T8 uniform. The series connection of the primary windings of the transformer T7 and the transformer T9 makes the closed loop current including the secondary windings of the transformer T7 and the transformer T9 uniform. Further, the series connection of the primary windings of the transformer T10 and the transformer T12 equalizes the closed loop current including the secondary windings of the transformer T10 and the transformer T12. Further, the series connection of the primary windings of the transformer T11 and the transformer T13 makes the closed loop current including the secondary windings of the transformer T11 and the transformer T13 uniform. Furthermore, the series connection of the primary windings of the transformer T14 and the transformer T16 equalizes the closed loop current including the secondary windings of the transformer T14 and the transformer T16. Further, the series connection of the primary windings of the transformer T15 and the transformer T17 makes the closed loop current including the secondary windings of the transformer T15 and the transformer T17 uniform. Further, the series connection of the primary windings of the transformer T18 and the transformer T20 makes the closed loop current including the secondary windings of the transformer T18 and the transformer T20 uniform. Further, the series connection of the primary windings of the transformer T19 and the transformer T1 makes the closed loop current including the secondary windings of the transformer T19 and the transformer T1 uniform. In this way, the current uniformity is propagated by being connected so that the closed loop goes around in a daisy chain through the transformer. Since the circuit has made a round, the current balance ability is somewhat reduced, but only a slight brightness gradient occurs, and brightness unevenness does not occur.

  Further, the series connection of the primary windings of the transformer is all suppressed to two series. In addition, the discharge tube is also restrained in series in the closed loop provided on the secondary winding side of the transformer. In such a case, the sensitivity of abnormality detection is increased in the voltage detection circuit connected via the voltage detection terminal.

  An example of a circuit to which the voltage detection terminals S1 to S10 are connected is shown in FIG. The voltage detection terminal S1 is the anode of the diode D1, the voltage detection terminal S2 is the anode of the diode D2, the voltage detection terminal S3 is the anode of the diode D3, the voltage detection terminal S4 is the anode of the diode D4, and the voltage detection terminal S5 is the diode. The voltage detection terminal S6 is connected to the anode of the diode D6, the voltage detection terminal S7 is connected to the anode of the diode D7, the voltage detection terminal S8 is connected to the anode of the diode D8, and the voltage detection terminal S9 is connected to the anode of the diode D9. The detection terminal S10 is connected to the anode of the diode D10. The cathodes of all the diodes D1 to D10 are connected to one end of the resistor R2. In this way, the maximum voltage among the voltages at any of the voltage detection terminals appears at one end of the resistor R2. The other end of the resistor R2 is connected to one end of the capacitor C1, one end of the resistor R1, and the terminal EV_SENS. The other end of the resistor R1 and the other end of the capacitor C1 are grounded. An abnormality on the secondary winding side of the transformer is detected by a circuit connected to the terminal EV_SENS.

  The potential detected at the voltage detection terminal will be described with reference to FIG. In FIG. 4, the INV + terminal, the INV− terminal, and the voltage detection terminals S1 to S10 serving as the midpoint thereof are represented on the horizontal axis, and the voltage is represented on the vertical axis. In FIG. 4, the thick line c represents the relationship between normal potentials, the lower right bold line c represents the positive peak at the INV− terminal, and the lower left thick line represents the positive at the INV + terminal. The peak case is shown. On the other hand, for example, when the INV + terminal side is in a low impedance state, the potential relationship is as indicated by a one-dot chain line b. That is, when the INV− terminal has a positive peak, the line has a downward convex line, and when the INV + terminal has a positive peak, the line has a convex line. Looking at the potential at the midpoint, it may be higher than normal. Further, for example, when the INV-terminal side is in a low impedance state, the potential relationship is as indicated by a dotted line a. That is, the INV− terminal has a convex polygonal line when the peak is positive, and the INV + terminal has a convex polygonal line when the peak is positive. Looking at the potential at the midpoint, it may be higher than normal.

  In this way, if two primary windings as shown in FIG. 2 are used in series, even if synchronous detection is not performed, as shown in FIG. Can do. Even if the two discharge tubes in the closed loop are simultaneously balanced and become abnormal, the potential rises at the adjacent voltage detection terminals on both sides thereof. Therefore, it is possible to detect an impedance abnormality for all the discharge tubes with a circuit that takes an OR with a diode as shown in FIG.

  In some cases, a discharge tube lighting circuit as shown in FIGS. However, in the method in which only the primary windings are connected in series as shown in FIG. 5, the current in the secondary winding is equalized, but two transformers are required for each discharge tube, and there are too many primary transformers. If the windings are connected in series, the impedance on the primary winding side becomes too low, and the ratio of resistance components such as the lead wire portion and the soldering portion increases, which may lead to deterioration in efficiency. Further, as shown in FIG. 6, there may be employed a method in which only the secondary winding side of the transformer is connected in series to form a closed loop. In this case, the current on the secondary winding side of the transformer is equalized. However, when a large number of discharge tubes are connected in series, there is a problem that the current equalization accuracy deteriorates due to the stray capacitance. In addition, since the secondary winding of the transformer is a high voltage line, there is a difficulty in securing an abnormal discharge withstand voltage. Furthermore, as shown in FIG. 7, it is also possible to adopt a simple system in which the primary winding side of the transformer is connected in series and the secondary winding of the transformer and the discharge tube are connected in series to form a closed loop. However, there is no problem compared with FIG. 5 and FIG. 6, for example, in order to light 20 discharge tubes, the primary winding side is 5 series, and the secondary winding side discharge tubes are 4 series. When the discharge tube is turned on or more, the wiring and impedance problems recur.

  On the other hand, in the discharge tube lighting circuit 10 as in the present embodiment shown in FIG. 2, the problems of current equalization and impedance on the primary winding side do not occur.

2. Embodiment 2
A discharge tube lighting circuit 20 according to a second embodiment of the present invention is shown in FIG. The discharge tube lighting circuit 20 in FIG. 8 includes transformers T21 to T40 and discharge tubes LP21 to LP40. The discharge tubes LP21 to LP24 are the first set, the discharge tubes LP25 to LP28 are the second set, the discharge tubes LP29 to LP32 are the third set, the discharge tubes LP33 to LP36 are the fourth set, and the discharge tubes LP37 to LP40 are the fifth set. Make a pair. The discharge tubes in each set are connected in series. Further, the transformers connected to the discharge tubes in each set also belong to the same set.

  The terminal P1 of the primary winding of the transformer T21 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S5 and the terminal P1 of the primary winding of the transformer T39. A terminal P2 of the primary winding of the transformer T39 is connected to the INV− terminal. That is, the primary winding of the transformer T21 belonging to the first set and the primary winding of the transformer T39 belonging to the fifth set are connected in series.

  A terminal S1 of the secondary winding of the transformer T21 is connected to one end of the discharge tube LP21, and the other end of the discharge tube LP21 is connected to a terminal S2 of the secondary winding of the transformer T24. A terminal S1 of the secondary winding of the transformer T24 is connected to one end of the discharge tube LP24, and the other end of the discharge tube LP24 is connected to a terminal S2 of the secondary winding of the transformer T23. A terminal S1 of the secondary winding of the transformer T23 is connected to one end of the discharge tube LP23, and the other end of the discharge tube LP23 is connected to a terminal S2 of the secondary winding of the transformer T22. A terminal S1 of the secondary winding of the transformer T22 is connected to one end of the discharge tube LP22, and the other end of the discharge tube LP22 is connected to a terminal S2 of the secondary winding of the transformer T21. As described above, the discharge tubes LP21 to LP24 and the transformers T21 to T24 belong to the first set and are connected in series to form a closed loop. The discharge tubes LP21 to LP24 included in this closed loop are driven by differential floating.

  The terminal P1 of the primary winding of the transformer T22 is connected to the voltage detection terminal S10 and the terminal P2 of the primary winding of the transformer T36. A terminal P1 of the primary winding of the transformer T36 is connected to the INV + terminal. The terminal P2 of the primary winding of the transformer T22 is connected to the INV− terminal. That is, the primary winding of the transformer T22 belonging to the first set and the primary winding of the transformer T36 belonging to the fourth set are connected in series.

  Further, the terminal P1 of the primary winding of the transformer T23 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S1 and the terminal P1 of the primary winding of the transformer T25. A terminal P2 of the primary winding of the transformer T25 is connected to the INV− terminal. That is, the primary winding of the transformer T23 belonging to the first set and the primary winding of the transformer T25 belonging to the second set are connected in series.

  The terminal P1 of the primary winding of the transformer T24 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S6 and the terminal P1 of the primary winding of the transformer T30. A terminal P2 of the primary winding of the transformer T30 is connected to the INV− terminal. That is, the primary winding of the transformer T24 belonging to the first set and the primary winding of the transformer T30 belonging to the third set are connected in series.

  As described above, the primary winding terminal P1 of the transformer T25 is connected to the voltage detection terminal S1 and the primary winding terminal P2 of the transformer T23, and the primary winding terminal P2 of the transformer T25 is connected to INV. -It is connected to the terminal. That is, the primary winding of the transformer T25 belonging to the second set and the primary winding of the transformer T23 belonging to the first set are connected in series.

  The terminal S1 of the secondary winding of the transformer T25 is connected to one end of the discharge tube LP25, and the other end of the discharge tube LP25 is connected to the terminal S2 of the secondary winding of the transformer T28. A terminal S1 of the secondary winding of the transformer T28 is connected to one end of the discharge tube LP28, and the other end of the discharge tube LP28 is connected to a terminal S2 of the secondary winding of the transformer T27. A terminal S1 of the secondary winding of the transformer T27 is connected to one end of the discharge tube LP27, and the other end of the discharge tube LP27 is connected to a terminal S2 of the secondary winding of the transformer T26. A terminal S1 of the secondary winding of the transformer T26 is connected to one end of the discharge tube LP26, and the other end of the discharge tube LP26 is connected to a terminal S2 of the secondary winding of the transformer T25. As described above, the discharge tubes LP25 to LP28 and the transformers T25 to T28 belong to the second set and are connected in series to form a closed loop. The discharge tubes LP25 to LP28 included in the closed loop are also driven by differential floating.

  Further, the terminal P1 of the primary winding of the transformer T26 is connected to the voltage detection terminal S9 and the terminal P2 of the primary winding of the transformer T40, and the terminal P2 of the primary winding of the transformer T26 is connected to the INV− terminal. Has been. A terminal P1 of the primary winding of the transformer T40 is connected to the INV + terminal. That is, the primary winding of the transformer T26 belonging to the second set and the primary winding of the transformer T40 belonging to the fifth set are connected in series.

  The terminal P1 of the primary winding of the transformer T27 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S2 and the terminal P1 of the primary winding of the transformer T29. A terminal P2 of the primary winding of the transformer T29 is connected to the INV− terminal. That is, the primary winding of the transformer T27 belonging to the second set and the primary winding of the transformer T29 belonging to the third set are connected in series.

  The terminal P1 of the primary winding of the transformer T28 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S7 and the terminal P1 of the primary winding of the transformer T34. A terminal P2 of the primary winding of the transformer T34 is connected to the INV− terminal. That is, the primary winding of the transformer T28 belonging to the second set and the primary winding of the transformer T34 belonging to the fourth set are connected in series.

  As described above, the primary winding terminal P1 of the transformer T29 is connected to the voltage detection terminal S2 and the primary winding terminal P2 of the transformer T27, and the primary winding terminal P2 of the transformer T29 is connected to the INV. -It is connected to the terminal. That is, the primary winding of the transformer T29 belonging to the third set and the primary winding of the transformer T27 belonging to the second set are connected in series.

  The terminal S1 of the secondary winding of the transformer T29 is connected to one end of the discharge tube LP29, and the other end of the discharge tube LP29 is connected to the terminal S2 of the secondary winding of the transformer T32. A terminal S1 of the secondary winding of the transformer T32 is connected to one end of the discharge tube LP32, and the other end of the discharge tube LP32 is connected to a terminal S2 of the secondary winding of the transformer T31. A terminal S1 of the secondary winding of the transformer T31 is connected to one end of the discharge tube LP31, and the other end of the discharge tube LP31 is connected to a terminal S2 of the secondary winding of the transformer T30. A terminal S1 of the secondary winding of the transformer T30 is connected to one end of the discharge tube LP30, and the other end of the discharge tube LP30 is connected to a terminal S2 of the secondary winding of the transformer T29. As described above, the discharge tubes LP29 to LP32 and the transformers T29 to T32 belong to the third group and are connected in series to form a closed loop. The discharge tubes LP29 to LP32 included in the closed loop are also driven by differential floating.

  As described above, the terminal P1 of the primary winding of the transformer T30 is connected to the voltage detection terminal S6 and the terminal P2 of the primary winding of the transformer T24, and the terminal P2 of the primary winding of the transformer T30 is Connected to INV- terminal. That is, the primary winding of the transformer T30 belonging to the third set and the primary winding of the transformer T24 belonging to the first set are connected in series.

  The terminal P1 of the primary winding of the transformer T31 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S3 and the terminal P1 of the primary winding of the transformer T33. A terminal P2 of the primary winding of the transformer T33 is connected to the INV− terminal. That is, the primary winding of the transformer T31 belonging to the third set and the primary winding of the transformer T33 belonging to the fourth set are connected in series.

  The terminal P1 of the primary winding of the transformer T32 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S8 and the terminal P1 of the primary winding of the transformer T38. A terminal P2 of the primary winding of the transformer T38 is connected to the INV− terminal. That is, the primary winding of the transformer T32 belonging to the third set and the primary winding of the transformer T38 belonging to the fifth set are connected in series.

  As described above, the primary winding terminal P1 of the transformer T33 is connected to the voltage detection terminal S3 and the primary winding terminal P2 of the transformer T31, and the primary winding terminal P2 of the transformer T33 is connected to the INV. -It is connected to the terminal. That is, the primary winding of the transformer T33 belonging to the third set and the primary winding of the transformer T31 belonging to the second set are connected in series.

  The terminal S1 of the secondary winding of the transformer T33 is connected to one end of the discharge tube LP33, and the other end of the discharge tube LP33 is connected to the terminal S2 of the secondary winding of the transformer T36. The terminal S1 of the secondary winding of the transformer T36 is connected to one end of the discharge tube LP36, and the other end of the discharge tube LP36 is connected to the terminal S2 of the secondary winding of the transformer T35. A terminal S1 of the secondary winding of the transformer T35 is connected to one end of the discharge tube LP35, and the other end of the discharge tube LP35 is connected to a terminal S2 of the secondary winding of the transformer T34. The terminal S1 of the secondary winding of the transformer T34 is connected to one end of the discharge tube LP34, and the other end of the discharge tube LP34 is connected to the terminal S2 of the secondary winding of the transformer T33. As described above, the discharge tubes LP33 to LP36 and the transformers T33 to T36 belong to the fourth set and are connected in series to form a closed loop. The discharge tubes LP33 to LP36 included in the closed loop are also driven by differential floating.

  As described above, the primary winding terminal P1 of the transformer T34 is connected to the voltage detection terminal S7 and the primary winding terminal P2 of the transformer T28, and the primary winding terminal P2 of the transformer T34 is connected to the INV. -It is connected to the terminal. That is, the primary winding of the transformer T34 belonging to the fourth set and the primary winding of the transformer T28 belonging to the second set are connected in series.

  The terminal P1 of the primary winding of the transformer T35 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S4 and the terminal P1 of the primary winding of the transformer T37. A terminal P2 of the primary winding of the transformer T37 is connected to the INV− terminal. That is, the primary winding of the transformer T35 belonging to the fourth set and the primary winding of the transformer T37 belonging to the fifth set are connected in series.

  As described above, the terminal P1 of the primary winding of the transformer T36 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S10 and the terminal P1 of the primary winding of the transformer T22. That is, the primary winding of the transformer T36 belonging to the fourth set and the primary winding of the transformer T22 belonging to the first set are connected in series.

  Furthermore, as described above, the terminal P1 of the primary winding of the transformer T37 is connected to the voltage detection terminal S4 and the terminal P2 of the primary winding of the transformer T35, and the terminal P2 of the primary winding of the transformer T37 is , INV- terminal. That is, the primary winding of the transformer T37 belonging to the fifth set and the primary winding of the transformer T35 belonging to the fourth set are connected in series.

  The terminal S1 of the secondary winding of the transformer T37 is connected to one end of the discharge tube LP37, and the other end of the discharge tube LP37 is connected to the terminal S2 of the secondary winding of the transformer T40. A terminal S1 of the secondary winding of the transformer T40 is connected to one end of the discharge tube LP40, and the other end of the discharge tube LP40 is connected to a terminal S2 of the secondary winding of the transformer T39. A terminal S1 of the secondary winding of the transformer T39 is connected to one end of the discharge tube LP39, and the other end of the discharge tube LP39 is connected to a terminal S2 of the secondary winding of the transformer T38. The terminal S1 of the secondary winding of the transformer T38 is connected to one end of the discharge tube LP38, and the other end of the discharge tube LP38 is connected to the terminal S2 of the secondary winding of the transformer T37. As described above, the discharge tubes LP37 to LP40 and the transformers T37 to T40 belong to the fifth set and are connected in series to form a closed loop. The discharge tubes LP37 to LP40 included in the closed loop are also driven by differential floating.

  As described above, the terminal P1 of the primary winding of the transformer T38 is connected to the voltage detection terminal S8 and the terminal P2 of the primary winding of the transformer T32. The terminal P2 of the primary winding of the transformer T38 is connected to the INV -It is connected to the terminal. That is, the primary winding of the transformer T38 belonging to the fifth set and the primary winding of the transformer T32 belonging to the third set are connected in series.

  Further, as described above, the terminal P1 of the primary winding of the transformer T39 is connected to the voltage detection terminal S5 and the terminal P2 of the primary winding of the transformer T21, and the terminal P2 of the primary winding of the transformer T39 is , INV- terminal. That is, the primary winding of the transformer T39 belonging to the fifth set and the primary winding of the transformer T21 belonging to the first set are connected in series.

  Furthermore, as described above, the terminal P1 of the primary winding of the transformer T40 is connected to the INV + terminal, and the terminal P2 is connected to the voltage detection terminal S9 and the terminal P1 of the primary winding of the transformer T26. Yes. That is, the primary winding of the transformer T40 belonging to the fifth set and the primary winding of the transformer T26 belonging to the second set are connected in series.

  The INV + terminal is connected to a first terminal of an inverter circuit (not shown), and the INV− terminal is connected to a second terminal of the inverter circuit. Further, the voltage detection terminals S1 to S10 are connected to the circuit shown in FIG.

  The main difference between the first embodiment and the second embodiment is that the number of discharge tubes included in the closed loop is changed from two to four. Thus, when the number of discharge tubes included in the closed loop is four, the primary windings of the four transformers can be connected to the primary windings of another set of transformers. In the present embodiment, the primary windings of four transformers are connected to the primary winding of any other transformer. In the case of the first set of transformers, the transformer is connected to any one of the second to fifth sets of transformers. Further, when the discharge tubes are arranged in a line as shown in FIG. 8, on the left side of the discharge tube, the primary windings of the transformers of adjacent groups (5 groups are 1 group and 4 groups) are cascaded in series. In the right side of the discharge tube, the primary windings of two pairs of transformers separated from each other are connected in cascade.

  The state of connection between groups is shown in FIG. In FIG. 9, a dotted line represents a connection to an adjacent set, and a solid line represents a connection to a set separated by two. The group connected by the dotted line is connected to the primary winding of the left transformer of the discharge tube, and the group connected by the solid line is connected to the primary winding of the right transformer of the discharge tube. In this way, since any pair has a series connection of primary windings, the accuracy of current uniformity is high. Further, since the farthest connection is between two groups on the right side, the coupling is stronger than in the first embodiment, and the current uniformity is improved.

3. Embodiment 3
FIG. 10 illustrates a discharge tube lighting circuit 30 according to a third embodiment. The discharge tube lighting circuit 30 includes transformers T41 to T60 and discharge tubes LP41 to LP60. In the present embodiment, the first set is configured by the transformers T51, T53, T58, and T60, the second set is configured by the transformers T47, T49, T54, and T56, and the third set is configured by the transformers T43, T45, T50, and T52. The fourth set is configured by the transformers T41, T59, T46, and T48, and the fifth set is configured by the transformers T55, T57, T42, and T44.

  A terminal P1 of the primary winding of the transformer T41 is connected to a terminal P2 of the primary winding of the transformer T59, and a terminal P2 of the primary winding of the transformer T41 is connected to a terminal P1 of the primary winding of the transformer T46. Yes. A terminal P2 of the primary winding of the transformer T46 is connected to a terminal P1 of the primary winding of the transformer T48, and a terminal P2 of the primary winding of the transformer T48 is connected to the −INV terminal. A terminal P1 of the primary winding of the transformer T59 is connected to the + INV terminal. Thus, the primary windings of the fourth set of transformers T41, T59, T46, and T48 are connected in series.

  The terminal S1 of the secondary winding of the transformer T41 is connected to one end of the discharge tube LP41, and the other end of the discharge tube LP41 is connected to the terminal S1 of the secondary winding of the transformer T42. The terminal S2 of the secondary winding of the transformer T42 is connected to one end of the discharge tube LP42, and the other end of the discharge tube LP42 is connected to the terminal S2 of the secondary winding of the transformer T41. Thus, the secondary windings of the transformers T41 and T42 and the discharge tubes LP41 and LP42 are connected in series to form a closed loop. The discharge tubes LP41 and LP42 included in the closed loop are driven by differential floating.

  A terminal P1 of the primary winding of the transformer T42 is connected to a terminal P2 of the primary winding of the transformer T57, and a terminal P1 of the primary winding of the transformer T57 is connected to a terminal P2 of the primary winding of the transformer T55. A terminal P1 of the primary winding of the transformer T55 is connected to the + INV terminal. The primary winding terminal P2 of the transformer T42 is connected to the primary winding terminal P1 of the transformer T44, and the primary winding terminal P2 of the transformer T44 is connected to the -INV terminal. Thus, the primary windings of the fifth set of transformers T42, T44, T55, and T57 are connected in series.

  The terminal S1 of the secondary winding of the transformer T44 is connected to one end of the discharge tube LP43, and the other end of the discharge tube LP43 is connected to the terminal S1 of the secondary winding of the transformer T43. The terminal S2 of the secondary winding of the transformer T43 is connected to one end of the discharge tube LP44, and the other end of the discharge tube LP44 is connected to the terminal S2 of the secondary winding of the transformer T44. Thus, the secondary windings of the transformers T43 and T44 and the discharge tubes LP43 and LP44 are connected in series to form a closed loop. The discharge tubes LP43 and LP44 included in the closed loop are also driven by differential floating.

  A terminal P1 of the primary winding of the transformer T43 is connected to the + INV terminal. The terminal P2 of the primary winding of the transformer T43 is connected to the terminal P1 of the primary winding of the transformer T45. A terminal P2 of the primary winding of the transformer T45 is connected to a terminal P1 of the primary winding of the transformer T50, and a terminal P2 of the primary winding of the transformer T50 is connected to a terminal P1 of the primary winding of the transformer T52. . A terminal P2 of the primary winding of the transformer T52 is connected to the -INV terminal. Thus, the primary windings of the third set of transformers T43, T45, T50, and T52 are connected in series.

  The terminal S1 of the secondary winding of the transformer T45 is connected to one end of the discharge tube LP45, and the other end of the discharge tube LP45 is connected to the terminal S1 of the secondary winding of the transformer T46. The terminal S2 of the secondary winding of the transformer T46 is connected to one end of the discharge tube LP46, and the other end of the discharge tube LP46 is connected to the terminal S2 of the secondary winding of the transformer T45. As described above, the secondary windings of the transformers T45 and T46 and the discharge tubes LP45 and LP46 are connected in series to form a closed loop. The discharge tubes LP45 and LP46 included in the closed loop are also driven by differential floating.

  Furthermore, the secondary winding terminal S1 of the transformer T48 is connected to one end of the discharge tube LP47, and the other end of the discharge tube LP47 is connected to the secondary winding terminal S1 of the transformer T47. A terminal S2 of the secondary winding of the transformer T47 is connected to one end of the discharge tube LP48, and the other end of the discharge tube LP48 is connected to a terminal S2 of the secondary winding of the transformer T48. Thus, the secondary windings of the transformers T47 and T48 and the discharge tubes LP47 and LP48 are connected in series to form a closed loop. The discharge tubes LP47 and LP48 included in the closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T47 is connected to the + INV terminal, and the terminal P2 is connected to the terminal P1 of the primary winding of the transformer T49. The primary winding terminal P2 of the transformer T49 is connected to the primary winding terminal P1 of the transformer T54, and the primary winding terminal P2 of the transformer T54 is connected to the primary winding terminal P1 of the transformer T56. A terminal P2 of the primary winding of the transformer T56 is connected to the -INV terminal. Thus, the primary windings of the second set of transformers T47, T49, T54, and T56 are connected in series.

  The terminal S1 of the secondary winding of the transformer T49 is connected to one end of the discharge tube LP49, and the other end of the discharge tube LP49 is connected to the terminal S1 of the secondary winding of the transformer T50. A terminal S2 of the secondary winding of the transformer T50 is connected to one end of the discharge tube LP50, and the other end of the discharge tube LP50 is connected to a terminal S2 of the secondary winding of the transformer T49. As described above, the secondary windings of the transformers T49 and T50 and the discharge tubes LP49 and LP50 are connected in series to form a closed loop. The discharge tubes LP49 and LP50 included in the closed loop are also driven by differential floating.

  Further, the terminal S1 of the secondary winding of the transformer T52 is connected to one end of the discharge tube LP51, and the other end of the discharge tube LP51 is connected to the terminal S1 of the secondary winding of the transformer T51. The terminal S2 of the secondary winding of the transformer T51 is connected to one end of the discharge tube LP52, and the other end of the discharge tube LP52 is connected to the terminal S2 of the secondary winding of the transformer T52. As described above, the secondary windings of the transformers T51 and T52 and the discharge tubes LP51 and LP52 are connected in series to form a closed loop. The discharge tubes LP51 and LP52 included in this closed loop are also driven by differential floating.

  The terminal P1 of the primary winding of the transformer T51 is connected to the + INV terminal, and the terminal P2 is connected to the terminal P1 of the primary winding of the transformer T53. A terminal P2 of the primary winding of the transformer T53 is connected to a terminal P1 of the primary winding of the transformer T58, and a terminal P2 of the primary winding of the transformer T58 is connected to a terminal P1 of the primary winding of the transformer T60. A terminal P2 of the primary winding of the transformer T60 is connected to the -INV terminal. Thus, the primary windings of the first set of transformers T51, T53, T58, and T60 are connected in series.

  The terminal S1 of the secondary winding of the transformer T53 is connected to one end of the discharge tube LP53, and the other end of the discharge tube LP53 is connected to the terminal S1 of the secondary winding of the transformer T54. The terminal S2 of the secondary winding of the transformer T54 is connected to one end of the discharge tube LP54, and the other end of the discharge tube LP54 is connected to the terminal S2 of the secondary winding of the transformer T53. As described above, the secondary windings of the transformers T53 and T54 and the discharge tubes LP53 and LP54 are connected in series to form a closed loop. The discharge tubes LP53 and LP54 included in the closed loop are also driven by differential floating.

  Further, the terminal S1 of the secondary winding of the transformer T56 is connected to one end of the discharge tube LP55, and the other end of the discharge tube LP55 is connected to the terminal S1 of the secondary winding of the transformer T55. A terminal S2 of the secondary winding of the transformer T55 is connected to one end of the discharge tube LP56, and the other end of the discharge tube LP56 is connected to a terminal S2 of the secondary winding of the transformer T56. Thus, the secondary windings of the transformers T55 and T56 and the discharge tubes LP55 and LP56 are connected in series to form a closed loop. The discharge tubes LP55 and LP56 included in the closed loop are also driven by differential floating.

  The terminal S1 of the secondary winding of the transformer T57 is connected to one end of the discharge tube LP57, and the other end of the discharge tube LP57 is connected to the terminal S1 of the secondary winding of the transformer T58. A terminal S2 of the secondary winding of the transformer T58 is connected to one end of the discharge tube LP58, and the other end of the discharge tube LP58 is connected to a terminal S2 of the secondary winding of the transformer T57. Thus, the secondary windings of the transformers T57 and T58 and the discharge tubes LP57 and LP58 are connected in series to form a closed loop. The discharge tubes LP57 and LP58 included in the closed loop are also driven by differential floating.

  Further, the terminal S1 of the secondary winding of the transformer T59 is connected to one end of the discharge tube LP59, and the other end of the discharge tube LP59 is connected to the terminal S1 of the secondary winding of the transformer T60. A terminal S2 of the secondary winding of the transformer T60 is connected to one end of the discharge tube LP60, and the other end of the discharge tube LP60 is connected to a terminal S2 of the secondary winding of the transformer T59. As described above, the secondary windings of the transformers T59 and T60 and the discharge tubes LP59 and LP60 are connected in series to form a closed loop. The discharge tubes LP59 and LP60 included in the closed loop are also driven by differential floating.

  The + INV terminal is connected to a first terminal of an inverter circuit (not shown), and the −INV terminal is connected to a second terminal of the inverter circuit.

  Thus, the secondary windings of the four transformers belonging to the first set belong to four separate closed loops. The other secondary winding transformers included in the closed loop belong to the second group, the third group, the fourth group, and the fifth group. Further, the secondary windings of the four transformers belonging to the second set belong to four separate closed loops. The other secondary winding transformers included in the closed loop belong to the first group, the third group, the fourth group, and the fifth group.

  The secondary windings of the four transformers belonging to the third set belong to four separate closed loops. The other secondary winding transformer included in the closed loop belongs to the first group, the second group, the fourth group, and the fifth group. The secondary windings of the four transformers belonging to the fourth group belong to four separate closed loops. The other secondary winding transformer included in the closed loop belongs to the first group, the second group, the third group, and the fifth group. The secondary windings of the four transformers belonging to the fifth group belong to four separate closed loops. The other secondary winding transformer included in the closed loop belongs to the first group, the second group, the third group, and the fourth group.

  The difference between the first embodiment and the third embodiment is that four primary windings of the transformer are in series. As a result, as schematically shown in FIG. 11, since any pair is connected through one closed loop including the secondary winding of the transformer, the accuracy of current uniformity is high. Since the secondary winding side of the transformer is limited to two discharge tubes, this also increases the accuracy of current uniformity. In FIG. 11, ● indicates that the transformer on the right side of the discharge tube is connected via a closed loop, and ○ indicates that the transformer on the left side of the discharge tube is connected via a closed loop. All the pairs are connected to the other pairs on the left and right sides via a closed loop.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the number of primary windings connected in series and the number of discharge tubes connected to the secondary winding can be implemented other than the examples described above. Alternatively, not all of the transformers belonging to one set may be connected to another set of transformers, but only a part of the transformer may be connected to another set of transformers. Further, the present invention can be applied to lamps such as LEDs other than the discharge tube.

It is a figure which shows the example of a conventional circuit. 1 is a circuit diagram according to a first embodiment of the present invention. It is a figure which shows the circuit example connected to a voltage detection terminal in the 1st Embodiment and 2nd Embodiment of this invention. It is a figure showing the relationship between a terminal and an electric potential. It is a figure which shows the example of a circuit which makes the primary winding of a transformer in series. It is a figure which shows the circuit example which makes the secondary winding of a transformer serial. It is a figure which shows the circuit example which connects the primary winding and secondary winding of a transformer separately in series. It is a circuit diagram in the 2nd Embodiment of this invention. It is a figure which shows the connection relation between the groups in the 2nd Embodiment of this invention. It is a circuit diagram in a 3rd embodiment of the present invention. It is a figure which shows the connection relation between the groups in the 3rd Embodiment of this invention.

Explanation of symbols

R resistance L coil C capacitor T transformer D diode

Claims (16)

A plurality of closed loops in which a predetermined number of lamps and secondary windings of the predetermined number of transformers are connected in series;
A lamp lighting circuit in which at least one of primary windings of a transformer used in each closed loop is connected in series with a primary winding of another transformer used in the closed loop. A plurality of closed loops in which a predetermined number of lamps and secondary windings of the predetermined number of transformers are connected in series;
A lamp lighting circuit in which all of the primary windings of the transformer used in each of the closed loops are connected in series with the primary windings of different transformers used in the closed loop.   The lamp lighting circuit according to claim 2, wherein the predetermined number is two. A first closed loop in which two lamps and two transformer secondary windings are connected in series so that the lamp and transformer secondary windings alternate;
A second closed loop in which two lamps and two transformer secondary windings are connected in series so that the lamp and transformer secondary windings alternate;
A third closed loop in which two lamps and two transformer secondary windings are connected in series so that the lamp and transformer secondary windings alternate;
Have
The primary winding of the first transformer used in the first closed loop and the primary winding of any transformer used in the second closed loop are connected in series,
A lamp lighting circuit in which a primary winding of a second transformer used in the first closed loop and a primary winding of any transformer used in the third closed loop are connected in series. A plurality of closed loops in which a first predetermined number of lamps and secondary windings of the first predetermined number of transformers are connected in series;
A primary winding of a second predetermined number of transformers used in different closed loops among the transformers used in the plurality of closed loops is connected in series,
At least one of the primary windings of another transformer used in a group of closed loops of which the secondary winding of the second predetermined number of transformers forms a part is used in a closed loop other than the group of closed loops. A lamp lighting circuit connected in series with the primary winding of the transformer. A plurality of closed loops in which a first predetermined number of lamps and secondary windings of the first predetermined number of transformers are connected in series;
Transformers used in the plurality of closed loops are grouped every second predetermined number,
The primary windings of the transformers in the group are connected in series,
A lamp lighting circuit in which another transformer used in a closed loop in which a secondary winding of a transformer in the group forms a part belongs to another group. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary closed loop and the secondary closed loop are coupled via the transformer,
At least one of the secondary side closed loops is coupled to at least two other secondary side closed loops via the primary side closed loop.   8. The lamp lighting circuit according to claim 7, wherein at least one of the secondary side closed loops is coupled to one other secondary side closed loop through the primary side closed loop. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary closed loop and the secondary closed loop are coupled via the transformer,
All of the secondary side closed loops are coupled to all other secondary side closed loops through the primary side closed loop or the primary side closed loop and other secondary side closed loops.   10. The lamp lighting circuit according to claim 9, wherein the total number of the transformers is smaller than the product of the total number of the primary side closed loops and the total number of the secondary closed loops. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary closed loop and the secondary closed loop are coupled via the transformer,
At least one of the primary side closed loops is coupled to at least two other primary side closed loops via the secondary side closed loop.   12. The lamp lighting circuit according to claim 11, wherein at least one of the primary side closed loops is coupled to one other primary side closed loop through the primary side closed loop. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary closed loop and the secondary closed loop are coupled via the transformer,
All the said primary side closed loop couple | bonds with all the said other primary side closed loops via the said secondary side closed loop or the said secondary side closed loop, and another primary side closed loop. The lamp lighting circuit characterized by the above-mentioned.   14. The lamp lighting circuit according to claim 13, wherein the total number of the transformers is smaller than the product of the total number of the primary side closed loops and the total number of the secondary closed loops. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary closed loop and the secondary closed loop are coupled via the transformer,
At least one of the secondary closed loops is coupled to at least two other secondary closed loops via the primary closed loop;
At least one of the primary side closed loops is coupled to at least two other primary side closed loops via the secondary side closed loop. A lamp lighting circuit including a plurality of transformers in which a primary winding is connected to a power source and a secondary winding is connected to a lamp,
A plurality of primary closed loops in which at least two primary windings are arranged in series;
A plurality of secondary closed loops in which at least two secondary windings are arranged in series;
Comprising
The primary side closed loop and the secondary side closed loop are alternately connected in a chain via the transformer,
A lamp lighting circuit comprising at least three alternate coupling portions of the primary side closed loop and the secondary side closed loop.

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