Fluorescent x-ray analysis device and power supply device

Abstract

To reduce a turn-off surge voltage while keeping a distance between a switching element and a primary winding of a transformer.SOLUTION: A power supply for applying a tube voltage to a target includes: at least one transformer; a switching circuit which is connected to the primary side of the at least one transformer; and a substrate to which the switching circuit and the at least one transformer are connected, and which has a first layer and a second layer. The at least one transformer includes a first primary winding and a second primary winding in the primary side. A first wiring pattern for connecting the first primary winding and the switching circuit is formed in the first layer. A second wiring pattern for connecting the second primary winding and the switching circuit is formed in the second layer. When the substrate is viewed from a stacking direction in a planar view, the first layer and the second layer are disposed so that at least a part of the first wiring pattern overlaps with the second wiring pattern.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a fluorescent X-ray analyzer and a power supply device.

Background Art

[0002] Conventionally, in a method of irradiating a sample with X-rays to analyze the sample, an X-ray generator has been used. In the X-ray generator, X-rays are generated by applying a high voltage called a tube voltage between a cathode electrode and a target electrode. In the X-ray generator, a converter as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-187929) may be used to boost the voltage. For example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-212072) describes an X-ray generator that generates X-rays using a DC / DC converter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a switching element such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used in a converter, a surge voltage may be generated when the switching element is controlled from the on state to the off state. If the surge voltage exceeds the rated voltage value of the switching element, the switching element may be damaged. Although the occurrence of a failure due to the surge voltage can be suppressed by using a switching element with a high rated voltage value, the cost increases.

[0005] The magnitude of the surge voltage generated varies depending on the magnitude of the loop inductance of the path for one cycle including the switching element. For example, in the power supply device described in Patent Document 1, if the inductance component between the switching element and the primary winding of the transformer is reduced, the generated surge voltage will be reduced. That is, if the length of the wiring from the switching element to the primary winding is shortened, the magnitude of the generated surge voltage can be reduced.

[0006] However, both the switching element and the primary winding of the transformer are heating elements. When the physical distance between the switching element and the primary winding of the transformer becomes small, the heating elements become concentrated, and the temperature of the power supply device rises.

[0007] The present disclosure has been made to solve the above-described problems, and an object thereof is to reduce the turn-off surge voltage while maintaining the distance between the switching element and the primary winding of the transformer.

Means for Solving the Problems

[0008] The fluorescent X-ray analyzer according to one aspect of the present disclosure includes an X-ray tube that includes a filament and a target and irradiates a sample with primary X-rays, a detector that detects secondary X-rays generated from the sample, and a power supply that applies a tube voltage to the target. The power supply includes at least one transformer, a switching circuit connected to the primary side of at least one transformer, and a substrate having a first layer and a second layer to which the switching circuit and at least one transformer are connected. The at least one transformer includes a first primary winding and a second primary winding on the primary side. The first wiring pattern connecting the first primary winding and the switching circuit is formed on the first layer, and the second wiring pattern connecting the second primary winding and the switching circuit is formed on the second layer. The first layer and the second layer are arranged such that at least a part of the first wiring pattern overlaps the second wiring pattern when the substrate is viewed in a plan view from the stacking direction.

[0009] A power supply device according to an aspect of the present disclosure is a power supply device that applies a tube voltage to a target disposed in an X-ray tube. The power supply device includes at least one transformer, a switching circuit connected to a primary side of the at least one transformer, and a substrate to which the switching circuit and the at least one transformer are connected and which has a first layer and a second layer. The at least one transformer includes a first primary winding and a second primary winding on the primary side. A first wiring pattern connecting the first primary winding and the switching circuit is formed in the first layer, and a second wiring pattern connecting the second primary winding and the switching circuit is formed in the second layer. The first layer and the second layer are arranged such that at least a part of the first wiring pattern overlaps the second wiring pattern when the substrate is viewed in a plan view from the stacking direction.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to reduce the turn-off surge voltage while maintaining the distance between the switching element and the primary winding of the transformer.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0012] [Embodiment 1] This embodiment will be described in detail with reference to the drawings. For the same or corresponding parts in the drawings, the same reference numerals are given, and the description thereof will not be repeated in principle.

[0013] <Configuration of Power Supply Device and X-ray Tube> FIG. 1 is a diagram schematically showing a power supply device 100 and an X-ray tube 200 included in a fluorescent X-ray analyzer 1000. The fluorescent X-ray analyzer 1000 is, for example, an energy dispersive type fluorescent X-ray analyzer (EDX: Energy Dispersive X-ray Fluorescence Spectrometer). In this embodiment, an example in which a power supply device 100 that generates primary X-rays is applied to the fluorescent X-ray analyzer 1000 will be described.

[0014] As shown in FIG. 1, the fluorescent X-ray analyzer 1000 includes a power supply device 100, an X-ray tube 200, and a detector 300. The power supply device 100 applies a voltage to the X-ray tube 200 to excite the primary X-rays 10. The primary X-rays 10 are irradiated onto the sample S. The sample S irradiated with the primary X-rays 10 emits fluorescent X-rays 20. The fluorescent X-rays 20 emitted from the sample S are referred to as "secondary X-rays" with respect to the primary X-rays. The detector 300 detects the fluorescent X-rays 20. Thereby, the fluorescent X-ray analyzer 1000 can perform quantitative analysis or qualitative analysis of the sample S.

[0015] Inside the X-ray tube 200, a target Tg1 and a filament F1 are arranged. The target Tg1 is the anode, and the filament F1 is the cathode. In the X-ray tube 200, the target Tg1 and the filament F1 are arranged at intervals from each other. The power supply device 100 includes a filament power supply unit 110, a high-voltage power supply unit 120, and a tube current control unit 130.

[0016] The filament power supply unit 110 heats the filament F1 by supplying current to the filament F1. Hereinafter, the current supplied to the filament F1 by the filament power supply unit 110 is referred to as the "filament current".

[0017] The high-voltage power supply unit 120 applies a high voltage between the target Tg1 and the filament F1. Hereinafter, the high voltage applied by the high-voltage power supply unit 120 is referred to as the "tube voltage". The high-voltage power supply unit 120 uses a rectifier, a converter, a Cockcroft-Walton circuit, etc., to boost the DC voltage converted from the commercial power supply using a switching power supply and generate a high voltage. Note that the high-voltage power supply unit 120 can correspond to the "power supply" in the present disclosure.

[0018] As shown in FIG. 1, the high-voltage power supply unit 120 is connected to the target Tg1 via the power line L3. Also, the high-voltage power supply unit 120 is connected to the ground terminal GND via the power line L5. Inside the X-ray tube 200, thermoelectrons are generated by heating the filament F1 by the filament power supply unit 110. The thermoelectrons collide with the target Tg1 when a tube voltage is applied between the filament F1 and the target Tg1 by the high-voltage power supply unit 120. Thereby, the primary X-ray 10 is excited.

[0019] As shown in FIG. 1, the filament power supply unit 110 is connected to the filament F1 via the power line L1 and the power line L1A. The power line L1 is connected to one end of the filament F1, and the power line L1A is connected to the other end of the filament F1. The terminals T1 and T1A of the filament power supply unit 110 are connected to the power lines L1 and L1A, respectively. The terminals T2 and T2A of the power supply device 100 are connected to the filament F1.

[0020] The connection point Cp1 is a connection point between the connection point of the terminals T1 and T2 and the connection point of the terminals T1A and T2A. A resistor R322 is connected between the connection point Cp1 and the connection point of the terminals T1 and T2. A resistor R316 is connected between the connection point Cp1 and the connection point of the terminals T1A and T2A.

[0021] One end of the power line L4 is connected to the connection point Cp1, and the other end of the power line L4 is connected to the ground terminal GND via a resistor. Note that one end of the power line L4 may be connected to either the connection point of the terminals T1 and T2 or the connection point of the terminals T1A and T2A instead of the connection point Cp1.

[0022] The tube current control unit 130 performs feedback control to adjust the output of the filament power supply unit 110 based on the current value of the current flowing through the power line L4. More specifically, the tube current control unit 130 detects the tube current value flowing through the power line L4 by converting the tube current flowing through the power line L4 into a voltage value with a resistor and amplifying it by an amplifier Am1. The tube current control unit 130 transmits the detected tube current value to the filament current control unit 111. The filament power supply unit 110 adjusts the filament current output based on the tube current value detected by the tube current control unit 130.

[0023] In the X-ray fluorescence analyzer 1000 of the present embodiment, the voltage is boosted using a DC-DC converter for boosting inside the high-voltage power supply unit 120. Hereinafter, the internal configuration of the DC-DC converter 500 for boosting included in the high-voltage power supply unit 120 will be described with reference to FIG. 2.

[0024] FIG. 2 is a diagram for explaining the internal configuration of a step-up DCDC converter 500 included in the high-voltage power supply unit 120 in Embodiment 1. The DCDC converter 500 in Embodiment 1 is a DCDC converter, and more specifically, a push-pull converter.

[0025] As shown in FIG. 2, the DCDC converter 500 includes a transformer primary-side circuit 401, a transformer secondary-side circuit 402, and a transformer 30. The transformer 30 includes a primary winding Tr11, Tr12 included in the transformer primary-side circuit 401 and a secondary winding Tr2 included in the transformer secondary-side circuit 402. Note that the transformer 30 may correspond to the "at least one transformer" in the present disclosure. Also, the primary winding Tr11 may correspond to the "first primary winding" in the present disclosure. Further, the primary winding Tr12 may correspond to the "second primary winding" in the present disclosure.

[0026] The DCDC converter 500 boosts the DC voltage of 24V applied from the power supply voltage VCC by driving the switching elements Mf1, Mf2. The DC voltage applied from the power supply voltage VCC is generated by rectifying a commercial power supply or the like. Note that the DC voltage applied from the power supply voltage VCC may be a voltage other than 24V. The voltage boosted by the DCDC converter 500 is further boosted to the output voltage of the high-voltage power supply unit 120 by a Cockcroft-Walton circuit or the like. The output voltage of the high-voltage power supply unit 120 is, for example, 60 kV.

[0027] As shown in FIG. 2, the primary winding Tr11 has an end H1 and an end H3. In the transformer primary-side circuit 401, a path Pt3 is connected to the end H3 of the primary winding Tr11. The path Pt3 is a path between the inductor L10 and the end H3. Also, a path Pt1 is connected to the end H1 of the primary winding Tr11. The path Pt1 is a path between the end H1 and the drain terminal of the switching element Mf1.

[0028] The primary winding Tr12 has an end H2 and an end H4. A path Pt4 is connected to the end H4 of the primary winding Tr12. The path Pt4 is a path between the inductor L10 and the end H4. Also, a path Pt2 is connected to the end H2 of the primary winding Tr12. The path Pt2 is a path between the end H2 and the drain terminal of the switching element Mf2.

[0029] Both ends of the inductor L10 are connected to the ground terminal GND via a plurality of capacitors. Specifically, capacitors C5, C6, and C7 are connected in parallel between one end of the inductor L10 and the ground terminal GND. Also, capacitors C8 to C12 are connected in parallel between the other end of the inductor L10 and the ground terminal GND. The capacitors C5 to C12 function as bypass capacitors for removing AC components.

[0030] The power supply voltage VCC is connected to the end H3 of the primary winding Tr11 via the path Pt3 and the inductor L10. On the other hand, the drain terminal of the switching element Mf1 is connected to the end H1 of the primary winding Tr11 via the path Pt1. In Embodiment 1, the switching element Mf1 is, for example, a MOSFET and is an element for switching the supply of current to the primary winding Tr11. A snubber circuit Sn1 is connected between the drain terminal and the source terminal of the switching element Mf1. The snubber circuit Sn1 is a protection circuit that suppresses the transient high voltage generated when the switch in the switching element Mf1 is turned off.

[0031] The drive circuit 350 is connected to the gate terminal of the switching element Mf1 via the resistor R2. The drive circuit 350 performs PWM (Pulse Width Modulation) control on the switching element Mf1. A resistor R4 and a bidirectional zener diode D1 are connected in parallel between the gate terminal and the source terminal of the switching element Mf1. The bidirectional zener diode D1 is provided to protect the switching element Mf1 when an overvoltage occurs at the gate terminal of the switching element Mf1.

[0032] Similarly, the circuit connected to the primary winding Tr12 will also be described. The power supply voltage VCC is connected to the end H4 of the primary winding Tr12 via the path Pt4 and the inductor L10. On the other hand, the switching element Mf2 is connected to the end H2 of the primary winding Tr12 via the path Pt2. The switching element Mf2 is, for example, a MOSFET, similar to the switching element Mf1, and is an element for switching the supply of current to the primary winding Tr12.

[0033] A snubber circuit Sn2 is connected between the drain terminal and the source terminal of the switching element Mf2. The snubber circuit Sn2 is a protection circuit that suppresses the transient high voltage generated when the switch of the switching element Mf2 is turned off. In a certain aspect, the switching elements Mf1 and Mf2 may be IGBTs (Insulated Gate Bipolar Transistors) instead of MOSFETs. Note that the switching element Mf1 may correspond to the "first switching element" in the present disclosure. Also, the switching element Mf2 may correspond to the "second switching element" in the present disclosure. Furthermore, both the switching element Mf1 and the switching element Mf2 may correspond to the "switching circuit" in the present disclosure. Also, the snubber circuit Sn1 may correspond to the "first snubber circuit" in the present disclosure. The snubber circuit Sn2 may correspond to the "second snubber circuit" in the present disclosure.

[0034] The drive circuit 350 is connected to the gate terminal of the switching element Mf2 via the resistor R6. The drive circuit 350 performs PWM control on the switching element Mf2. A resistor R8 and a bidirectional zener diode D2 are connected in parallel between the gate terminal and the source terminal of the switching element Mf2. The bidirectional zener diode D2 is provided to protect the switching element Mf2 when an overvoltage occurs at the gate terminal of the switching element Mf2.

[0035] The drive circuit 350 repeatedly turns on and off the switching element Mf1 and repeatedly turns on and off the switching element Mf2 to alternately supply current to the primary winding Tr11 and the primary winding Tr12. The drive circuit 350 controls each of the switching elements Mf1 and Mf2 so that the switching elements Mf1 and Mf2 do not simultaneously turn on.

[0036] As shown in FIG. 2, one end of each of the resistors R10 and R11 is connected to the source terminals of the switching elements Mf1 and Mf2, respectively. The other end of the resistor R10 is connected to the ground terminal GND. Similarly, the other end of the resistor R11 is connected to the ground terminal GND.

[0037] As described above, the high-voltage power supply unit 120 in the present embodiment includes a DCDC converter 500 that repeatedly drives the switching elements Mf1 and Mf2 to boost the voltage. In the present embodiment, a surge voltage may be generated when the switching elements Mf1 and Mf2 are switched from the on state to the off state. Hereinafter, this surge voltage is referred to as a "turn-off surge voltage".

[0038] The cause of the generation of the turn-off surge voltage is that the parasitic capacitance of the switching element is excessively charged due to the influence of the loop inductance of the one-round path including the switching element. When the turn-off surge voltage exceeds the rated voltage value of the switching elements Mf1 and Mf2, the switching elements Mf1 and Mf2 may malfunction.

[0039] If the leakage inductance between the primary windings Tr11 and Tr12 is reduced, the inductance component between the switching element Mf1 and the primary winding Tr11 becomes smaller, and the turn-off surge voltage generated in the switching element Mf1 becomes smaller. If the length of the path Pt1 is shortened, the inductance component becomes smaller. However, when the length of the path Pt1 is shortened, the physical distance between the switching element Mf1, which is a heating element, and the primary winding Tr11 becomes shorter, and the heating elements become densely packed. Similarly, when the length of the path Pt2 is shortened, while the magnitude of the turn-off surge voltage generated in the switching element Mf2 can be reduced, the physical distance between the switching element Mf2, which is a heating element, and the primary winding Tr12 becomes shorter, and the heating elements become densely packed.

[0040] Therefore, in the high-voltage power supply unit 120 of the present embodiment, the paths Pt1 and Pt2 are implemented as wiring patterns on the printed circuit board. In the present embodiment, by using the printed circuit board Sb1 and adopting a parallel flat plate structure in which the paths Pt1 and Pt2 having a flat plate structure are arranged in parallel, respectively, the degree of coupling between the primary winding Tr11 and the primary winding Tr12 is improved, and the leakage inductance between the primary windings Tr11 and Tr12 is reduced. By being able to reduce the leakage inductance between the primary windings Tr11 and Tr12, it is possible to suppress an increase in the magnitude of the turn-off surge voltage generated while suppressing a decrease in the distance between the switching element Mf1 and the primary windings Tr11 and Tr12. Note that the path Pt1 may correspond to the "first wiring pattern" in the present disclosure. The path Pt2 may correspond to the "second wiring pattern" in the present disclosure.

[0041] FIG. 3 is a plan view of the printed circuit board Sb1 in Embodiment 1. The printed circuit board Sb1 is a board having a plurality of layers laminated in the Z-axis direction. In the following description, the normal direction of the printed circuit board Sb1 is defined as the Z-axis direction, and the plane perpendicular to the Z-axis direction is defined as the X-axis and the Y-axis. Also, in each figure, the positive direction of the Z-axis may be referred to as the upper side, and the negative direction may be referred to as the lower side. The Z-axis direction may correspond to the "lamination direction" in the present disclosure.

[0042] In this embodiment, the printed circuit board Sb1 has four layers LyT1, Ly1, Ly2, and LyB1. The layer LyT1 is the layer exposed on the positive Z-axis side and is the outermost surface of the printed circuit board Sb1. The upper part of FIG. 3 shows a view of the layer LyT1 when viewed from the positive Z-axis side. The lower part of FIG. 3 shows a cross-sectional view of the four layers LyT1, Ly1, Ly2, and LyB1. As shown in the lower part of FIG. 3, the layers are arranged in the order of LyT1, Ly1, Ly2, and LyB1 from the positive Z-axis side. The thickness of each layer in the Z-axis direction is, for example, 1.1 mm. Note that 1.1 mm is only an example, and the thickness of each layer in the Z-axis direction may be other than 1.1 mm, or each layer may have a different thickness. Further, the number of layers included in the printed circuit board Sb1 is not limited to four layers, and may be, for example, two layers, six layers, or the like.

[0043] Referring to the upper part of FIG. 3, a transformer 30 is arranged on the positive Y-axis side of the printed circuit board Sb1. The ends H1 and H3 of the primary winding Tr11 and the ends H2 and H4 of the primary winding Tr12 are connected to the printed circuit board Sb1. Switching elements Mf1 and Mf2 are arranged on the negative Y-axis side of the printed circuit board Sb1.

[0044] Snubber circuits Sn1 and Sn2 are mounted on the positive Z-axis side of the layer LyT1 of the printed circuit board Sb1. The printed circuit board Sb1 has a conductive wiring pattern inside, and the transformer 30 and the switching elements Mf1 and Mf2 are electrically connected by the wiring pattern.

[0045] Hereinafter, with reference to FIGS. 4 and 5, the layers Ly1 and Ly2 arranged on the negative Z-axis side of the layer LyT1 will be described. FIG. 4 is a plan view of the layer Ly1 included in the printed circuit board Sb1 in Embodiment 1. In this embodiment, the layer Ly1 is the layer arranged on the negative Z-axis side of the layer LyT1 and is the layer adjacent to the layer LyT1. That is, the layer Ly1 is the second layer from the positive Z-axis side. Note that the layer Ly1 may correspond to the "first layer" in the present disclosure.

[0046] As shown in FIG. 4, a path Pt1 is formed as a wiring pattern on the layer Ly1. The path Pt1 electrically connects the primary winding Tr11 of the transformer 30 and the switching element Mf1. A snubber circuit Sn1 is connected to the path Pt1. The length between the end H1 of the primary winding Tr11 and the switching element Mf1 is the length Ds1.

[0047] FIG. 5 is a plan view of the layer Ly2 included in the printed circuit board Sb1 in the first embodiment. In the present embodiment, the layer Ly2 is a layer disposed on the negative Z-axis side of the layer Ly1. The layer Ly2 is adjacent to the layer Ly1 in the stacking direction. That is, the layer Ly2 is the third layer from the positive Z-axis side. Note that the layer Ly2 may correspond to the "second layer" in the present disclosure.

[0048] As shown in FIG. 5, a path Pt2 is formed as a wiring pattern on the layer Ly1. The path Pt2 electrically connects the primary winding Tr12 of the transformer 30 and the switching element Mf2. A snubber circuit Sn2 is connected to the path Pt2. The length between the end H2 of the primary winding Tr12 and the switching element Mf2 is the length Ds2.

[0049] In the present embodiment, the region Rg1 shown in FIG. 5 is a region where the path Pt2 and the path Pt1 overlap when viewed from the positive Z-axis side of the path Pt2 and the path Pt1. Both the path Pt1 and the path Pt2 have the shape shown as the region Rg1. That is, the path Pt1 is configured to at least partially overlap the path Pt2 when the printed circuit board Sb1 is viewed in plan. In the region shown as the region Rg1, the degree of magnetic field coupling between the path Pt1 and the path Pt2 is improved. Thereby, the mutual inductance between the primary winding Tr11 and the primary winding Tr12 is improved.

[0050] The mutual inductance between the primary winding Tr11 and the primary winding Tr12 is improved, that is, the leakage inductance between the primary windings Tr11 and Tr12 is reduced, and the loop inductance that causes the turn-off surge voltage is reduced. As a result, in the fluorescence X-ray analyzer 1000 of the present embodiment, the turn-off surge voltage can be reduced while maintaining the distance between the switching element and the primary winding of the transformer. The length Ds1 is, for example, 51 mm, and the length Ds2 is, for example, 43 mm.

[0051] In the present embodiment, with respect to the length Ds1 of 51 mm, the pattern width (length in the X-axis direction) of the path Pt1 is, for example, between 7 mm and 10 mm. With respect to the length Ds2 of 43 mm, the pattern width of the path Pt2 is, for example, between 7 mm and 10 mm. Note that the lengths Ds1 and Ds2 and the pattern widths of the paths Pt1 and Pt2 are examples and may be other sizes.

[0052] <Comparative Example> Hereinafter, the comparative example will be described with reference to FIGS. 6 and 7. FIG. 6 is a plan view for explaining the paths Pt1Z and Pt2Z in Comparative Example 1. In the following comparative examples, an example will be described in which the paths Pt1 and Pt2 in the present embodiment are formed as paths Pt1Z and Pt2Z that are cables instead of the wiring patterns of the printed circuit board Sb1.

[0053] In the example of FIG. 6, the switching element Mf1 and the primary winding Tr11 are connected by the path Pt1Z. The path Pt1Z is a cable disposed on the positive Z-axis side of the printed circuit board Sb1. Similarly, the switching element Mf2 and the primary winding Tr12 are connected by the path Pt2Z. The path Pt2Z is also a cable disposed on the positive Z-axis side of the printed circuit board Sb1. Further, FIG. 6 shows a path Pt3Z connecting the power supply voltage VCC and the primary winding Tr11 and a path Pt4Z connecting the power supply voltage VCC and the primary winding Tr12. The paths Pt3Z and Pt4Z are cables disposed on the positive Z-axis side of the printed circuit board Sb1, similar to the paths Pt1Z and Pt2Z.

[0054] In the region Rg2 shown in FIG. 6, the paths Pt1Z to Pt4Z are twisted together. By twisting together the paths Pt1Z to Pt4Z which are cables, the degree of coupling between the path Pt1Z and the path Pt2Z is improved compared to the case where the paths Pt1Z to Pt4Z are wired without being twisted together. In the comparative example, first, the path Pt1Z and the path Pt3Z are twisted together, and the path Pt2Z and the path Pt4Z are twisted together. Then, the twisted path Pt1Z and path Pt3Z, and the twisted path Pt2Z and path Pt4Z are further twisted together. In a comparative example of a certain aspect, other twisting orders may be used.

[0055] However, even when the paths Pt1Z to Pt4Z which are cables are twisted together as shown in FIG. 6, there are spaces between the cables, insulation covers of the cables, etc. Also, in the comparative example, the area where each path per unit length is adjacent is smaller than the area where each path per unit length is adjacent in Embodiment 1, and in the comparative example, the leakage inductance becomes large. From this, the degree of coupling between the path Pt1Z and the path Pt2Z in Comparative Example 1 is weaker than the degree of coupling between the path Pt1 and the path Pt2 which are superimposed as the wiring pattern shown in this embodiment. Therefore, although the length between the switching element Mf1 and the end H1 of the primary winding Tr11 in Comparative Example 1 is the same length Ds1 as in this embodiment, since the coupling between the path Pt1 and the path Pt2 is weaker than in this embodiment, the turn-off surge voltage generated becomes large.

[0056] FIG. 7 is a plan view for explaining the paths Pt1Z, Pt2Z in Comparative Example 2. In the example of FIG. 7, the paths Pt1Z, Pt2Z are formed as cables in the same manner as in the example of FIG. 6. In the example of FIG. 7, the length between the end H1 of the primary winding Tr11 and the switching element Mf1 is the length Ds3. The length Ds3 is shorter than the length Ds1 in this embodiment.

[0057] As described with reference to FIG. 6, when the paths Pt1Z to Pt4Z are realized as cables, the mutual inductance between the primary winding Tr11 and the primary winding Tr12 becomes small, and the leakage inductance between the primary windings Tr11 and Tr12 increases as compared with the present embodiment. In the example of FIG. 7, the length of the paths Pt1Z to Pt4Z itself is shortened to suppress an increase in the inductance component of the paths Pt1Z and Pt2Z.

[0058] However, in Comparative Example 2, the distance between the transformer 30 and the switching element Mf1 becomes short, and the heat generating elements are concentrated. The snubber circuits Sn1 and Sn2 are also heat generating elements like the transformer 30 and the switching element Mf1. The snubber circuits Sn1 and Sn2 are arranged in the vicinity of the transformer 30 and the switching elements Mf1 and Mf2. In the comparative example, since the distance between the transformer 30 and the switching element Mf1 is short, the distances between the transformer 30, the switching elements Mf1 and Mf2, and the snubber circuits Sn1 and Sn2 become small, and a plurality of heat generating elements are concentrated.

[0059] When a plurality of heat generating elements are concentrated, it may lead to an excessive increase in the temperature of the high-voltage power supply unit 120 due to the interaction. In the present embodiment, since the paths Pt1 and Pt2 are realized using the wiring pattern of the printed circuit board Sb1, it is possible to sufficiently secure the length Ds1 while suppressing an increase in the inductance component of the paths Pt1 and Pt2.

[0060] As a further comparative example, it is conceivable to protect the switching elements Mf1 and Mf2 from the turn-off surge voltage by increasing the capacitance of the capacitors included in the snubber circuits Sn1 and Sn2. However, by increasing the capacitance of the capacitors, the power consumed by the snubber circuits Sn1 and Sn2 increases, and the heat generation of the snubber circuits Sn1 and Sn2 becomes stronger. In the present embodiment, since the paths Pt1 and Pt2 are realized using the wiring pattern of the printed circuit board Sb1, it is possible to reduce the resistance of the snubber circuits Sn1 and Sn2 and the constants of the capacitors, and the power consumed by the snubber circuits Sn1 and Sn2 can be reduced.

[0061] [Embodiment 2] In Embodiment 1, an example in which one transformer 30 is connected to the printed circuit board Sb1 was described. In Embodiment 2, a configuration in which, in addition to the transformer 30, a transformer 30A is connected to the printed circuit board Sb1 will be described. Note that, in Embodiment 2, descriptions of configurations overlapping with those of the fluorescent X-ray analyzer 1000 of Embodiment 1 will not be repeated.

[0062] FIG. 8 is a plan view of the layer Ly1 included in the printed circuit board Sb1 in Embodiment 2. In Embodiment 2, in addition to the transformer 30, a transformer 30A is connected to the printed circuit board Sb1. Further, in addition to the switching element Mf1, a switching element Mf1A is connected to the printed circuit board Sb1. That is, in Embodiment 2, there are two configurations shown in FIG. 2.

[0063] As shown in FIG. 8, in addition to the path Pt1, a path Pt1A is formed as a wiring pattern on the layer Ly1. The path Pt1A electrically connects the primary winding of the transformer 30A and the switching element Mf1A. That is, the fluorescent X-ray analyzer 1000 of Embodiment 2 includes two transformer primary side circuits 401.

[0064] Note that, in Embodiment 2, the transformer 30 may correspond to the "first transformer" in the present disclosure. In Embodiment 2, the transformer 30A may correspond to the "second transformer" in the present disclosure. In Embodiment 2, the path Pt1 may correspond to the "first wiring pattern of the first transformer" in the present disclosure. In Embodiment 2, the path Pt1A may correspond to the "first wiring pattern of the second transformer" in the present disclosure.

[0065] FIG. 9 is a plan view of layer Ly2 included in printed circuit board Sb1 in Embodiment 2. As shown in FIG. 9, in addition to path Pt2, path Pt2A is formed as a wiring pattern on layer Ly2. Path Pt2A electrically connects the primary winding of transformer 30A and switching element Mf2A. A snubber circuit Sn2A is connected to path Pt2A.

[0066] Thus, the fluorescence X-ray analyzer 1000 of Embodiment 2 has two transformers. In Embodiment 2, path Pt1 connected to transformer 30 and path Pt1A connected to transformer 30A are formed on the same layer Ly1. Also, in Embodiment 2, path Pt2 connected to transformer 30 and path Pt2A connected to transformer 30A are formed on the same layer Ly2. It is desirable that the circuits connected to transformer 30 and the circuits connected to transformer 30A have the same configuration and characteristics. Note that in Embodiment 2, path Pt2 may correspond to the "second wiring pattern of the first transformer" in the present disclosure. In Embodiment 2, path Pt2A may correspond to the "second wiring pattern of the second transformer" in the present disclosure.

[0067] [Modification Example] In the present embodiment, layer Ly1 and layer Ly2 are adjacent to each other. However, in some aspects, other layers may be arranged between layer Ly1 and layer Ly2. Also, in the present embodiment, length Ds1 and length Ds2 are different lengths, but they may be the same length. Also, the shapes of path Pt1 and path Pt2 are not limited to the shapes shown in FIGS. 4 and 5, and may be other shapes.

[0068] Furthermore, in the present embodiment, as shown in FIG. 3, an example in which switching elements Mf1 and Mf2 are arranged at different positions in the X-axis direction has been described. However, switching element Mf1 may be arranged at a different position in the Z-axis direction or the Y-axis direction.

[0069] Further, in Embodiment 2, the path Pt1 and the path Pt1A may be formed in different layers, and the path Pt2 and the path Pt2A may be formed in different layers. For example, when the printed circuit board Sb1 is formed of four or more layers including the first layer to the fourth layer, the path Pt1 may be disposed in the first layer, the path Pt2 may be disposed in the second layer, the path Pt1A may be disposed in the third layer, and the path Pt2A may be disposed in the fourth layer.

[0070] [Aspect] Those skilled in the art will understand that the above-described plurality of exemplary embodiments are specific examples of the following aspects.

[0071] (Item 1) A fluorescent X-ray analyzer (1000) according to one aspect includes an X-ray tube (200) including a filament (F1) and a target (Tg1) that irradiates a sample (S) with primary X-rays (10), a detector (300) that detects secondary X-rays (20) generated from the sample, and a power supply (120) that applies a tube voltage to the target, wherein the power supply includes at least one transformer (30), a switching circuit (Mf1, Mf2) connected to a primary side of the at least one transformer, and a substrate (Sb1) having a first layer (Ly1) and a second layer (Ly2), to which the switching circuit and the at least one transformer are connected, wherein the at least one transformer includes a first primary winding (Tr11) and a second primary winding (Tr12) on the primary side, a first wiring pattern (Pt1) connecting the first primary winding and the switching circuit is formed in the first layer, and a second wiring pattern (Pt2) connecting the second primary winding and the switching circuit is formed in the second layer. The fluorescence X-ray analyzer (1000) is configured such that when the substrate is viewed in a plan view from the stacking direction (Z-axis direction), at least a part of the first wiring pattern overlaps with the second wiring pattern.

[0072] According to the fluorescence X-ray analyzer 1000 described in claim 1, it is to reduce the turn-off surge voltage while maintaining the distance between the switching element and the primary winding of the transformer.

[0073] (Claim 2) In the fluorescence X-ray analyzer (1000) described in claim 1, The first layer is a layer adjacent to the second layer in the stacking direction.

[0074] According to the fluorescence X-ray analyzer 1000 described in claim 2, the degree of coupling between the path Pt1 and the path Pt2 can be improved.

[0075] (Claim 3) In the fluorescence X-ray analyzer (1000) described in claim 1 or claim 2, The switching circuit includes a first switching element (Mf1) connected to the first primary winding by the first wiring pattern (Pt1), and a second switching element (Mf2) connected to the second primary winding by the second wiring pattern (Pt2).

[0076] According to the fluorescence X-ray analyzer 1000 described in claim 3, power can be supplied to the transformer 30 using a plurality of switching elements.

[0077] (Claim 4) In the fluorescence X-ray analyzer (1000) described in claim 3, The power supply further includes a first snubber circuit (Sn1) connected to the first primary winding and the first switching element, and a second snubber circuit (Sn2) connected to the second primary winding and the second switching element.

[0078] According to the fluorescent X-ray analyzer 1000 described in claim 4, it is possible to suppress the concentration of heat-generating elements including the snubber circuit.

[0079] (Claim 5) In the fluorescent X-ray analyzer (1000) according to any one of claims 1 to 4, the at least one transformer includes a first transformer (30) and a second transformer (30A), the first wiring pattern (Pt1) in the first transformer (30) and the first wiring pattern (Pt1A) in the second transformer (30A) are formed in the same first layer, the second wiring pattern (Pt2) in the first transformer (30) and the second wiring pattern (Pt2A) in the second transformer (30A) are formed in the same second layer.

[0080] According to the fluorescent X-ray analyzer 1000 described in claim 5, in a configuration having a plurality of transformers, the wiring patterns can be formed in the same layer, so that the characteristics of the primary side circuit 401 of the transformer shown in FIG. 2 can be made closer to the same between two systems for each transformer.

[0081] (Claim 6) A power supply device (100) according to one aspect is a power supply device (120) that applies a tube voltage to a target (Tg1) disposed in an X-ray tube (200), the power supply device includes at least one transformer (30), a switching circuit (Mf1, Mf2) connected to the primary side of the at least one transformer, a substrate (Sb1) to which the switching circuit and the at least one transformer are connected and which has a first layer (Ly1) and a second layer (Ly2), the at least one transformer includes a first primary winding (Tr11) and a second primary winding (Tr12) on the primary side, a first wiring pattern (Pt1) connecting the first primary winding and the switching circuit is formed in the first layer, The second wiring pattern (Pt2) that connects the second primary winding and the switching circuit is formed in the second layer, The first layer and the second layer are arranged such that at least a part of the first wiring pattern overlaps with the second wiring pattern when the substrate is viewed in a plan view from the stacking direction (Z-axis direction), in a power supply device (120).

[0082] According to the power supply device described in claim 6, it is to reduce the turn-off surge voltage while maintaining the distance between the switching element and the primary winding of the transformer.

[0083] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the description of the above embodiments but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of reference numerals

[0084] 30 Transformer, 100 Power supply device, 110 Filament power supply unit, 111 Filament current control unit, 120 High-voltage power supply unit, 130 Tube current control unit, 200 X-ray tube, 300 Detector, 350 Drive circuit, 401,402 Secondary circuit, 500 DCDC converter, 1000 Fluorescent X-ray analyzer, Am1,Am2 Amplifier, Cp1 Connection point, D1,D2 Bidirectional Zener diode, T1,T1A,T2A,T2 Terminal, Ds1,Ds2,Ds3 Length, F1 Filament, GND Ground terminal, H1~H4 End, L1A,L1,L3,L4,L5 Power line, L10 Inductor, Ly1,Ly2,LyT1 Layer Mf1,Mf2 Switching element, Pt1~Pt4,Pt1Z~Pt4Z Path, Rg1,Rg2 Region, S Sample, Sb1 Printed circuit board, Sn1,Sn2 Snubber circuit, Tg1 Target, Tr2 Secondary winding, Tr11,Tr12 Primary winding.

Claims

1. An X-ray tube that includes a filament and a target and irradiates a sample with primary X-rays, a detector that detects secondary X-rays generated from the sample, and a power supply that applies a tube voltage to the target, wherein the power supply includes at least one transformer, a switching circuit connected to a primary side of the at least one transformer, and a substrate having a first layer and a second layer, to which the switching circuit and the at least one transformer are connected, wherein the at least one transformer includes a first primary winding and a second primary winding on the primary side, a first wiring pattern that connects the first primary winding and the switching circuit is formed on the first layer, a second wiring pattern that connects the second primary winding and the switching circuit is formed on the second layer, and the first layer and the second layer are arranged such that at least a part of the first wiring pattern overlaps the second wiring pattern when the substrate is viewed in a plan view from the stacking direction. A fluorescent X-ray analyzer.

2. The fluorescent X-ray analyzer according to claim 1, wherein the first layer is a layer adjacent to the second layer in the stacking direction.

3. The switching circuit includes a first switching element connected to the first primary winding by the first wiring pattern, and a second switching element connected to the second primary winding by the second wiring pattern. The fluorescent X-ray analyzer according to claim 1 or claim 2.

4. The power supply further includes a first snubber circuit connected to the first primary winding and the first switching element, and a second snubber circuit connected to the second primary winding and the second switching element. The fluorescent X-ray analyzer according to claim 3.

5. The at least one transformer includes a first transformer and a second transformer, the first wiring pattern in the first transformer and the first wiring pattern in the second transformer are formed on the same first layer, and the second wiring pattern in the first transformer and the second wiring pattern in the second transformer are formed on the same second layer. The fluorescent X-ray analyzer according to claim 1 or claim 2.

6. A power supply device that applies a tube voltage to a target disposed in an X-ray tube, wherein the power supply device includes at least one transformer, A switching circuit connected to the primary side of the at least one transformer; A substrate having a first layer and a second layer, to which the switching circuit and the at least one transformer are connected; The at least one transformer includes a first primary winding and a second primary winding on the primary side; A first wiring pattern connecting the first primary winding and the switching circuit is formed on the first layer; A second wiring pattern connecting the second primary winding and the switching circuit is formed on the second layer; A power supply device in which the first layer and the second layer are arranged such that at least a part of the first wiring pattern overlaps the second wiring pattern when the substrate is viewed in plan from the stacking direction.

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