Power supply circuit for flash discharge tube

Abstract

This power supply circuit for a flash discharge tube comprises: a voltage supply source having one output terminal; a branching part which branches wiring connected to the output terminal into a first wiring and a second wiring; a main discharge capacitor connected to the first wiring; a trigger capacitor connected to the second wiring; a first rectifier element which is provided between the branching part in the first wiring and the main discharge capacitor and which passes a current from the branching part side to the main discharge capacitor side; and a second rectifier element which is provided between the branching part in the second wiring and the trigger capacitor and which passes a current from the branching part side to the trigger capacitor side.

Description

Power circuit for flash discharge tube

[0001] The present disclosure relates to a power circuit for a flash discharge tube.

[0002] As a technology related to a power circuit for a flash discharge tube, for example, Patent Document 1 describes a light source device including a power circuit including a voltage supply source, a main discharge capacitor and a trigger capacitor to which a voltage is supplied from the voltage supply source.

[0003] Japanese Patent No. 6783531

[0004] In an optical measurement device using a light source device as described above, in recent years, further miniaturization and stabilization of measurement performance have been demanded. Therefore, further miniaturization and stabilization of light output are also demanded for the light source device. To achieve this, miniaturization of the voltage supply source incorporated in the light source device and stabilization of the light output of the flash discharge tube are important.

[0005] An object of the present disclosure is to provide a power circuit for a flash discharge tube capable of stabilizing the light output of the flash discharge tube while achieving miniaturization of the voltage supply source.

[0006] The power circuit for a flash discharge tube of the present disclosure is [1] "a power circuit for a flash discharge tube, comprising: a voltage supply source having one output terminal; a branching portion that branches a wiring connected to the output terminal into a first wiring and a second wiring; a main discharge capacitor connected to the first wiring; a trigger capacitor connected to the second wiring; a first rectifying element provided between the branching portion and the main discharge capacitor in the first wiring, for passing a current from the branching portion side to the main discharge capacitor side; and a second rectifying element provided between the branching portion and the trigger capacitor in the second wiring, for passing a current from the branching portion side to the trigger capacitor side."

[0007] The power supply circuit for a flash discharge tube disclosed herein employs a voltage supply source having a single output terminal, thereby enabling miniaturization of the voltage supply source. Furthermore, the disclosers have conducted extensive research and discovered that the voltage fluctuation of the main discharge capacitor is influenced by charge transfer between the main discharge capacitor and the trigger capacitor. Therefore, in the power supply circuit for a flash discharge tube disclosed herein, a first rectifier element is provided between the branching point in the first wiring and the main discharge capacitor, and a second rectifier element is provided between the branching point in the second wiring and the trigger capacitor. This suppresses charge transfer between the main discharge capacitor and the trigger capacitor, thereby suppressing voltage fluctuations of the main discharge capacitor. Consequently, it is possible to stabilize the optical output of the flash discharge tube while miniaturizing the voltage supply source.

[0008] The power supply circuit for a flash discharge tube of this disclosure may also be [2] "the power supply circuit for a flash discharge tube according to [1], wherein no resistive element is provided between the second rectifier element and the trigger capacitor in the second wiring." In this case, it is possible to reduce the time required to charge the trigger capacitor and / or the input power.

[0009] The power supply circuit for a flash discharge tube of this disclosure may also be [3] "the power supply circuit for a flash discharge tube according to [1] or [2], comprising a plurality of first rectifier elements, wherein the plurality of first rectifier elements are connected in parallel or in series with each other between the branch portion of the first wiring and the main discharge capacitor." In this case, it is possible to suppress the current flowing through the first rectifier element from exceeding the rated current, or the voltage applied to the first rectifier element from exceeding the rated voltage.

[0010] The power supply circuit for a flash discharge tube of this disclosure may also be [4] "a power supply circuit for a flash discharge tube according to any one of [1] to [3], comprising a plurality of second rectifier elements, wherein the plurality of second rectifier elements are connected in parallel or in series with each other between the branch portion of the second wiring and the trigger capacitor." In this case, it is possible to suppress the current flowing through the second rectifier element from exceeding the rated current, or the voltage applied to the second rectifier element from exceeding the rated voltage.

[0011] The power supply circuit for a flash discharge tube of this disclosure may also be [5] "a power supply circuit for a flash discharge tube according to any one of [1] to [4], comprising a voltage limiting element provided between the second rectifier element and the trigger capacitor in the second wiring." In this case, the voltage limiting element can determine the voltage applied to the trigger capacitor.

[0012] The power supply circuit for a flash discharge tube of this disclosure may also be [6] "a power supply circuit for a flash discharge tube according to any one of [1] to [4], comprising a voltage limiting element provided between the branch portion and the second rectifier element in the second wiring." In this case, the voltage limiting element can determine the voltage applied to the trigger capacitor. Furthermore, it becomes possible to narrow the range of high voltage in the second wiring.

[0013] The power supply circuit for a flash discharge tube of this disclosure may also be [7] "a power supply circuit for a flash discharge tube according to any one of [1] to [6], comprising a trigger capacitor discharge circuit including a resistor connected in parallel with the trigger capacitor." In this case, the resistor can be used to configure a discharge path for discharging the charge stored in the trigger capacitor.

[0014] The power supply circuit for a flash discharge tube according to this disclosure may also be [8] "a power supply circuit for a flash discharge tube according to any one of [1] to [7], which is provided in a third wiring connected to the first wiring and the second wiring, and comprises a third rectifier element that allows current to pass from the second wiring side to the first wiring side." In this case, the third rectifier element can constitute a discharge path for discharging the charge stored in the trigger capacitor.

[0015] According to this disclosure, it is possible to provide a power supply circuit for a flash discharge tube that can stabilize the optical output of the flash discharge tube while miniaturizing the voltage supply source.

[0016] Figure 1 shows a part of the power supply circuit for a flash discharge tube according to an embodiment. Figure 2 shows another part of the power supply circuit for a flash discharge tube according to an embodiment. Figure 3 is a flowchart illustrating an example of operation of the power supply circuit for a flash discharge tube according to an embodiment. Figure 4 is a timing chart illustrating an example of operation of the power supply circuit for a flash discharge tube according to an embodiment. Figure 5(a) shows a part of the power supply circuit for a flash discharge tube according to the first modified example. Figure 5(b) shows a part of the power supply circuit for a flash discharge tube according to the second modified example. Figure 6(a) shows a part of the power supply circuit for a flash discharge tube according to the third modified example. Figure 6(b) shows a part of the power supply circuit for a flash discharge tube according to the fourth modified example. Figure 7 shows a part of the power supply circuit for a flash discharge tube according to the fifth modified example. Figure 8(a) shows a part of the power supply circuit for a flash discharge tube according to the sixth modified example. Figure 8(b) shows a part of the power supply circuit for a flash discharge tube according to the seventh modified example.

[0017] The embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0018] As shown in Figures 1 and 2, the power supply circuit 1 for the flashing discharge tube is a power supply circuit for a flashing discharge tube 10 used in, for example, an analytical instrument. The flashing discharge tube 10 is, for example, a xenon flash lamp. The power supply circuit 1 for the flashing discharge tube comprises a transformer T1, a branching section 3, a main discharge capacitor C1, a trigger capacitor C2, a Zener diode (voltage limiting element) D4, a trigger transformer T2, a thyristor Q2, a pulse branching circuit RC, and a diode D3.

[0019] The transformer T1 constitutes a voltage supply source 2. The voltage supply source 2 has one output terminal 21. In other words, the voltage supply source 2 does not have multiple terminals for outputting voltage, but only one. The voltage supply source 2 is a one-terminal voltage supply source. One wire 4 is connected to such a voltage supply source 2 via one output terminal 21. The output terminal 21 corresponds to one end of the secondary coil of the transformer T1.

[0020] Power input pins I1 and I3 are connected to both ends of the primary coil of transformer T1, respectively. Power input pin I1 is connected to, for example, the positive terminal of the power supply voltage. Power input pin I3 is connected to, for example, the reference potential (GND). Transistor Q1 is connected in series with the primary coil of transformer T1. A main discharge voltage control circuit SC, which controls the on / off charging of the main discharge capacitor C1, is connected to the gate of transistor Q1. In response to the input of a pulse signal from the main discharge voltage control circuit SC to transistor Q1, a pulse current flows through the primary coil and a pulse current flows through the secondary coil of transformer T1. As a result, voltage is supplied from the voltage supply source 2.

[0021] The branching section 3 branches the wiring 4 connected to the output terminal 21 into the first wiring 5 and the second wiring 6. In other words, the branching section 3 is a circuit component to which wiring 4 is connected as one input line, and to which the first wiring 5 and the second wiring 6 are connected as two output lines.

[0022] The main discharge capacitor C1 is a capacitor that stores charge (energy) to cause the flash discharge tube 10 to emit light. The main discharge capacitor C1 is connected to the first wiring 5. Both ends of the main discharge capacitor C1 are connected to the anode 11 and cathode 12 of the flash discharge tube 10, respectively. Voltage divider resistors R1 and R2 are connected in parallel to the main discharge capacitor C1. The charging voltage of the main discharge capacitor C1 is divided by the voltage divider resistors R1 and R2 and input to the main discharge voltage control circuit SC. In addition, the voltage divider resistors R1 and R2 constitute part of the discharge path that discharges the charge stored in the main discharge capacitor C1 when the voltage from the voltage supply source 2 is interrupted.

[0023] The trigger capacitor C2 is a capacitor that stores the charge used to trigger the flash discharge tube 10 to emit light. The trigger capacitor C2 is connected to the second wiring 6. The Zener diode D4 is provided between the branch 3 in the second wiring 6 and the trigger capacitor C2. In the illustrated example, the Zener diode D4 is provided between the second rectifier element D2 (described later) and the trigger capacitor C2 in the second wiring 6. The Zener diode D4 determines the voltage applied to the trigger capacitor C2. For example, the voltage applied to the trigger capacitor C2 can be determined as "the voltage applied to the main discharge capacitor C1 - the voltage applied to the Zener diode D4".

[0024] The trigger transformer T2 outputs a high-voltage pulse that triggers the light emission of the flash discharge tube 10. A trigger capacitor C2 is connected to one end of the primary coil of the trigger transformer T2. A pulse branching circuit RC is connected to both ends of the secondary coil of the trigger transformer T2.

[0025] Thyristor Q2 is connected in parallel to the primary coil of the trigger transformer T2. Thyristor Q2 is also connected to the trigger signal input pin I2. Thyristor Q2 turns ON when a trigger signal is input via the trigger signal input pin I2. As a result, the charge of the trigger capacitor C2 is output to the trigger transformer T2, which generates a high-voltage pulse, and this high-voltage pulse is applied to the flash discharge tube 10. Note that a transistor may be used instead of thyristor Q2.

[0026] The pulse branching circuit RC branches the high-voltage pulse output from the trigger transformer T2. The pulse branching circuit RC applies the branched high-voltage pulse to the anode 11, probe 13, and sparker 14 of the flash discharge tube 10. The pulse branching circuit RC includes capacitors C3, C4, C5 and resistors R3, R4, R5. Capacitors C3, C4, and C5 are connected in parallel to each other and connected to one end of the secondary coil of the trigger transformer T2. One end of capacitor C3 is connected to the anode 11, one end of capacitor C4 is connected to the probe 13, and one end of capacitor C5 is connected to the sparker 14. Resistor R3 is provided in the wiring between one end of capacitor C5 and the other end of the secondary coil of the trigger transformer T2. Resistor R4 is provided and connected in the wiring between one end of capacitor C4 and one end of resistor R3. Resistor R5 is provided in the wiring between one end of capacitor C3 and one end of capacitor C4.

[0027] Diode D3 is a rectifier element that prevents the high-voltage pulse output from the trigger transformer T2 from being applied to the upstream side. Diode D3 is provided in the wiring between one end of the voltage divider resistor R1 and one end of the capacitor C3. Diode D3 is an element that allows current from the branch section 3 and the main discharge capacitor C1 to pass to the anode 11 side.

[0028] The power supply circuit 1 for the flash discharge tube includes a first rectifier element D1 and a second rectifier element D2. The first rectifier element D1 is provided between the branch section 3 and the main discharge capacitor C1 in the first wiring 5. The first rectifier element D1 is an element that allows current to pass from the branch section 3 side to the main discharge capacitor C1 side. The first rectifier element D1 is, for example, a diode. The second rectifier element D2 is provided between the branch section 3 and the trigger capacitor C2 in the second wiring 6. The second rectifier element D2 is an element that allows current to pass from the branch section 3 side to the trigger capacitor C2 side. The second rectifier element D2 is, for example, a diode. No resistive element is provided between the second rectifier element D2 and the trigger capacitor C2 in the second wiring 6.

[0029] Next, an example of the operation of the flash discharge tube power supply circuit 1 will be explained with reference to the flowchart in Figure 3 and the graph in Figure 4. In each graph in Figure 4, the vertical axis represents the voltage of the main discharge capacitor C1, the voltage of the trigger capacitor C2, and the trigger signal, and the horizontal axis represents time.

[0030] First, a power supply voltage of, for example, several volts to over ten volts is input to the power supply input pin I1 (step S1). As a result, the main discharge voltage control circuit SC, voltage supply source 2, transistor Q1, first rectifier element D1, second rectifier element, voltage divider resistors R1 and R2 charge the main discharge capacitor C1 and trigger capacitor C2 with a predetermined voltage (several hundred volts) (step S2). At this time, the same voltage as that applied to the main discharge capacitor C1 is also applied between the anode 11 and cathode 12 of the flash discharge tube 10.

[0031] Next, the device remains in a standby state until a trigger signal is input from the trigger signal input pin I2. When a trigger signal is input, the thyristor Q2 switches from OFF to ON (YES in step S3, time t1). As a result, the charge stored in the trigger capacitor C2 is output to the trigger transformer T2, and a high-voltage pulse voltage is generated in the trigger transformer T2. This high-voltage pulse voltage is branched by the pulse branching circuit RC and applied to the flash discharge tube 10 (step S4). The high-voltage pulse voltage applied to the sparker 14 generates a sparker discharge inside the flash discharge tube 10 (step S5). As a result, the internal gas (e.g., xenon gas) inside the flash discharge tube 10 is ionized. A preliminary discharge is generated between the anode 11, cathode 12, and probe 13 (step S6, time t2).

[0032] Subsequently, the charge stored in the main discharge capacitor C1 is output to the flash discharge tube 10, causing a main discharge to occur inside the flash discharge tube 10, and the flash discharge tube 10 to emit light (step S7, time t3). After the dead time (the pause period from emission to resumption of charging) has elapsed since emission, if the power supply voltage input has not been stopped, the process proceeds to step S2 of the next cycle (NO in steps S8 and S9). Then, the flash discharge tube 10 repeatedly emits light as described above. Due to the presence of the dead time, the flash discharge tube 10 emits pulsed light rather than continuous light. On the other hand, if the power supply voltage input has been stopped after the dead time has elapsed since emission, the operation of the flash discharge tube power supply circuit 1 is terminated (YES in step S9).

[0033] As described above, the power supply circuit 1 for the flash discharge tube employs a voltage supply source 2 having one output terminal 21, which makes it possible to miniaturize the voltage supply source 2 compared to the case where multiple output terminals are provided. This makes it possible to miniaturize the power supply circuit 1 for the flash discharge tube, and by extension, the module including the power supply circuit 1 for the flash discharge tube. Furthermore, the disclosers have conducted extensive research and found that the voltage fluctuation of the main discharge capacitor C1 is affected by the charge transfer between the main discharge capacitor C1 and the trigger capacitor C2. Therefore, in the power supply circuit 1 for the flash discharge tube, a first rectifier element D1 is provided between the branch section 3 in the first wiring 5 and the main discharge capacitor C1, and a second rectifier element D2 is provided between the branch section 3 in the second wiring 6 and the trigger capacitor C2. This suppresses the charge transfer and suppresses the voltage fluctuation of the main discharge capacitor C1. For example, it is possible to suppress the discharge of charge stored in the main discharge capacitor C1 via the thyristor Q2, which reduces the amount of charge sent from the main discharge capacitor C1 to the flash discharge tube 10. The stability of the light output of the flash discharge tube 10 is affected by the voltage of the main discharge capacitor C1. Therefore, by suppressing voltage fluctuations of the main discharge capacitor C1, it is possible to stabilize the light output of the flash discharge tube 10. Thus, it is possible to stabilize the light output of the flash discharge tube 10 while miniaturizing the voltage supply source 2. Furthermore, if the first rectifier element D1 and the second rectifier element D2 are not provided, and a state occurs where the main discharge capacitor C1 does not discharge even when the thyristor Q2 is turned ON (so-called mis-flash), a current greater than the holding current may be supplied from the main discharge capacitor C1 to the thyristor Q2, causing the thyristor to remain ON (so-called latching). In this case, the main discharge capacitor C1 and the trigger capacitor C2 may not be able to reach a predetermined voltage, resulting in a problem where normal discharge and light emission operations cannot be performed. However, the flash discharge tube power supply circuit 1 can suppress such problems.

[0034] In the power supply circuit 1 for the flash discharge tube, no resistive element is provided between the second rectifier element D2 and the trigger capacitor C2 in the second wiring 6. In this case, it is possible to reduce the time required to charge the trigger capacitor C2 and / or the input power.

[0035] The power supply circuit 1 for the flash discharge tube includes a Zener diode D4 provided between the second rectifier element D2 and the trigger capacitor C2 in the second wiring 6. In this case, the Zener diode D4 can determine the voltage applied to the trigger capacitor C2.

[0036] Furthermore, for the flash discharge tube power supply circuit 1 and a comparative example flash discharge tube power supply circuit that does not have the first rectifier element D1 and the second rectifier element D2, a test was conducted to evaluate the stability of the flash discharge tube 10 by measuring the voltage change (energy equivalent) of the main discharge capacitor C1. As a result, while the voltage change was approximately 0.1% in the flash discharge tube power supply circuit of the comparative example, the voltage change was approximately 0.02% in the flash discharge tube power supply circuit 1, confirming the effect of stabilizing the light output of the flash discharge tube 10.

[0037] The embodiments described above are not limited to the above-described embodiments.

[0038] The flash discharge tube power supply circuit 1 of the above embodiment may include a plurality of first rectifier elements D11 to D1n (where n is an integer of 2 or more), as shown in Figure 5(a). These plurality of first rectifier elements D11 to D1n are connected in parallel to each other between the branch section 3 in the first wiring 5 and the main discharge capacitor C1. Each of the plurality of first rectifier elements D11 to D1n is configured in the same manner as the first rectifier element D1 described above.

[0039] In this power supply circuit 1 for a flash discharge tube, the above-mentioned effect is achieved, which allows for miniaturization of the voltage supply source 2 while stabilizing the light output of the flash discharge tube 10. Furthermore, since n first rectifier elements D1 are connected in parallel, the current flowing through each first rectifier element D1 is 1 / n compared to when only one first rectifier element D1 is connected, making it possible to suppress the current flowing through the first rectifier element D1 from exceeding the rated current.

[0040] Instead of or in addition to including n first rectifying elements D1 connected in parallel with each other, n second rectifying elements D2 connected in parallel with each other may be provided. In this case, it is possible to suppress the current flowing through the second rectifying element D2 from exceeding the rated current.

[0041] As shown in FIG. 5(b), the power supply circuit 1 for a flash discharge tube of the above embodiment may include a plurality of first rectifying elements D11 to D1n. These plurality of first rectifying elements D11 to D1n are connected in series with each other between the branch portion 3 in the first wiring 5 and the main discharge capacitor C1. Each of the plurality of first rectifying elements D11 to D1n is configured in the same manner as the above-described first rectifying element D1.

[0042] Even in such a power supply circuit 1 for a flash discharge tube, the above-described effect of enabling stabilization of the light output of the flash discharge tube 10 while reducing the size of the voltage supply source 2 is achieved. Further, since n first rectifying elements D1 are connected in series, the voltage applied to each of the first rectifying elements D1 becomes 1 / n compared to the case where one first rectifying element D1 is connected, and it is possible to suppress the voltage applied to the first rectifying element D1 from exceeding the rated voltage.

[0043] Instead of or in addition to including n first rectifying elements D1 connected in series with each other, n second rectifying elements D2 connected in series with each other may be provided. In this case, it is possible to suppress the voltage applied to the second rectifying element D2 from exceeding the rated voltage.

[0044] In the power supply circuit 1 for a flash discharge tube of the above embodiment, as shown in FIG. 6(a), a plurality of first rectifying elements D11 to Dmn (m is an integer of 2 or more) may be provided. These plurality of first rectifying elements D11 to Dmn are connected in parallel with each other and in series with each other between the branch portion 3 in the first wiring 5 and the main discharge capacitor C1. Specifically, a set of n first rectifying elements D1 connected in parallel with each other are connected in series with m sets. Each of the plurality of first rectifying elements D11 to Dmn is configured in the same manner as the above-described first rectifying element D1.

[0045] Even in such a power supply circuit 1 for a flash discharge tube, the above-described effect of enabling stabilization of the light output of the flash discharge tube 10 while reducing the size of the voltage supply source 2 is achieved. Further, since n first rectifying elements D1 are connected in parallel, the current flowing through each of the first rectifying elements D1 becomes 1 / n compared to the case where one first rectifying element D1 is connected, and it is possible to suppress the current flowing through the first rectifying element D1 from exceeding the rated current. Since m first rectifying elements D1 are connected in series, the voltage applied to each of the first rectifying elements D1 becomes 1 / m compared to the case where one first rectifying element D1 is connected, and it is possible to suppress the voltage applied to the first rectifying element D1 from exceeding the rated voltage.

[0046] In addition, instead of or in addition to including a plurality of first rectifying elements D1 connected in parallel with each other and in series with each other, a plurality of second rectifying elements D2 connected in parallel with each other and in series with each other may be provided. In this case, it is possible to suppress the voltage applied to the second rectifying element D2 from exceeding the rated current, and it is possible to suppress the current flowing through the second rectifying element D2 from exceeding the rated current.

[0047] In the above embodiment, as shown in FIG. 6(b), instead of the first rectifying element D1 which is a diode, a transistor 8 may be provided. By using the transistor 8, it is possible to reduce the power loss.

[0048] In the above embodiment, as shown in FIG. 7, the Zener diode D4 may be provided between the branch portion 3 in the second wiring 6 and the second rectifying element D2. In this case, the voltage applied to the trigger capacitor C2 can be determined by the Zener diode D4. Further, the high voltage range in the second wiring 6 becomes the range from the branch portion 3 to the Zener diode D4, and it is possible to narrow the high voltage range in the second wiring 6. In this case, it is advantageous in ensuring a certain distance or more between the conductive portions on the substrate on which the power supply circuit 1 for the flash discharge tube is mounted.

[0049] In the above embodiment, as shown in Figure 8(a), a trigger capacitor discharge circuit including resistors Rd1 and Rd2 connected to the trigger capacitor C2 may be provided. In this case, a discharge circuit (discharge path) for discharging the charge stored in the trigger capacitor C2 can be configured in which the discharge current flows in the order of trigger capacitor C2, trigger transformer T2, and resistor Rd1. Alternatively, a discharge circuit (discharge path) for discharging the charge stored in the trigger capacitor C2 can be configured in which the discharge current flows in the order of trigger capacitor C2 and resistor Rd2. Therefore, when power supply to the flash discharge tube power supply circuit 1 (input of power supply voltage to power supply input pin I1) is stopped, it is possible to accelerate the voltage drop of the trigger capacitor C2. Note that only one of resistors Rd1 or Rd2 may be provided.

[0050] In the above embodiment, a third rectifier element D6 may be provided, as shown in Figure 8(b). The third rectifier element D6 is provided on the third wiring 7 connected to the first wiring 5 and the second wiring 6. The third rectifier element D6 allows current to pass from the second wiring 6 side to the first wiring 5 side. The third rectifier element D6 is, for example, a diode. In this case, a discharge path can be configured in which the discharge current flows in the order of trigger capacitor C2, third rectifier element D6, voltage divider resistors R1, R2, and trigger transformer T2 to discharge the charge stored in the trigger capacitor C2. Therefore, when the power supply to the flash discharge tube power supply circuit 1 is stopped, it is possible to accelerate the voltage drop of the trigger capacitor C2. In addition, since the discharge path is configured using the third rectifier element D6 instead of resistors, power loss during charging can also be suppressed.

[0051] In the above embodiments, the flash discharge tube 10 is not particularly limited, and various known electron tubes may be used. The components in the above embodiments and modifications are not limited to the materials and shapes described above, and various materials and shapes can be applied. Furthermore, the components in the above embodiments and modifications can be arbitrarily applied to the components in other embodiments or modifications.

[0052] 1...Power supply circuit for flash discharge tube, 2...Voltage supply source, 3...Branch section, 4...Wiring, 5...First wiring, 6...Second wiring, 7...Third wiring, 10...Flash discharge tube, 21...Output terminal, C1...Main discharge capacitor, C2...Trigger capacitor, D1...First rectifier element, D2...Second rectifier element, D4...(Voltage limiting element), D6...Third rectifier element, Rd2, Rd2...Resistors.

Claims

1. A power supply circuit for a flash discharge tube, comprising: a voltage supply source having one output terminal; a branching section that branches a wire connected to the output terminal into a first wire and a second wire; a main discharge capacitor connected to the first wire; a trigger capacitor connected to the second wire; a first rectifier element provided between the branching section and the main discharge capacitor in the first wire, which allows current to pass from the branching section side to the main discharge capacitor side; and a second rectifier element provided between the branching section and the trigger capacitor in the second wire, which allows current to pass from the branching section side to the trigger capacitor side.

2. The power supply circuit for a flash discharge tube according to claim 1, wherein no resistive element is provided between the second rectifier element and the trigger capacitor in the second wiring.

3. The power supply circuit for a flash discharge tube according to claim 1 or 2, comprising a plurality of first rectifier elements, wherein the plurality of first rectifier elements are connected in parallel or in series with each other between the branch portion of the first wiring and the main discharge capacitor.

4. The power supply circuit for a flash discharge tube according to claim 1 or 2, comprising a plurality of the second rectifier elements, wherein the plurality of the second rectifier elements are connected in parallel or in series with each other between the branch portion and the trigger capacitor in the second wiring.

5. The power supply circuit for a flash discharge tube according to claim 1 or 2, further comprising a voltage limiting element provided between the second rectifier element and the trigger capacitor in the second wiring.

6. The power supply circuit for a flash discharge tube according to claim 1 or 2, further comprising a voltage limiting element provided between the branching portion and the second rectifier element in the second wiring.

7. The power supply circuit for a flash discharge tube according to claim 1 or 2, comprising a trigger capacitor discharge circuit including a resistor connected to the trigger capacitor.

8. The power supply circuit for a flash discharge tube according to claim 1 or 2, further comprising a third rectifier element provided in a third wiring connected to the first wiring and the second wiring, which allows current to pass from the second wiring side to the first wiring side.

Images