JPH03261364A - High-speed semiconductor switch - Google Patents

Abstract

PURPOSE:To reduce the inductance of a circuit and a wiring and suppress excess voltage generated in switching over by connecting snubber units, which are formed on printed boards, to the circuit. CONSTITUTION:Snubber units 26 made by mounting circuit components on the surfaces of printed boards 27 and plate electrode conductors 28a and 28b on both ends thereof are laminated and attached to a frame 22 close to a semiconductor stack 24. A plate conductor 29 is connected to heat sinks 11a at both sides of an element 10a and to an electrode conductor 28a of the snubber units. One end of a plate conductor 30 is closely brought into contact with the plate conductor 30 from another heat sink 11b through an insulator 31 and with the rear of a printed board 27 of the snubber units 26 and extended to another electrode conductor 28b for connection. The electrode conductors 25a and 25b of the semiconductor stack 24 are coaxial.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Field of Application) The present invention relates to a high-speed semiconductor switch for a pulse generator used in a laser, an accelerator, etc.

(Prior Art) Generally, high-speed, large-current pulse generators have been used in applied fields such as lasers and accelerators. These pulse generators use a capacitor for charging and discharging, a switching element that quickly discharges the voltage charged in the capacitor, a pulse transformer that boosts the voltage to a high voltage, and the like.

FIG. 3 is a diagram showing an example of a typical circuit configuration of this type of pulse generator, and shows an example of a circuit of a pulse generator using a semiconductor element as a switching element.

This pulse generator applies a predetermined voltage to a capacitor 1 from another circuit with the polarity shown in FIG. This generates a high voltage pulse between the UV terminals. On the other hand, a snubber circuit 4 includes a diode 5, a capacitor 6, and a resistor 7, and is used to prevent overvoltage caused by inductance when the switching element 2 is turned on and off.

That is, in pulse generators used in lasers, accelerators, etc., a short pulse waveform of approximately several + n5 ec to several μsec is required as the pulse width of the current applied to the load. Therefore, it is necessary to keep the inductance of the closed circuit 8 shown in FIG. 1 extremely small, and to keep the overvoltage generated by this inductance small. In order to reduce these inductances, it is necessary to reduce the inductance of the capacitor 1 and the leakage inductance of the switching element 2 and pulse transformer 3. In particular, it is necessary to reduce the wiring indance between the respective devices mentioned above, and to reduce the wiring inductance of the snubber circuit 4 to prevent overvoltage caused by these inductances.

An example of a conventional semiconductor switch will be described below with reference to FIGS. 4 and 5.

FIG. 4 shows a front view of the semiconductor switch, and FIG.
A BB arrow view in the figure is shown.

4 and 5, 9 is a semiconductor stack, which includes flat semiconductor switching elements 10a to 10C (hereinafter simply referred to as elements) and heat sinks lla to 11d that dissipate heat generated by the elements 10a to 10c. The electrode conductors 12a, 12 are laminated alternately, and electrode conductors 12a, 12 are placed on both ends of the layers.
b and insulating seat 13, press plates 14 a, 14 b,
It is constructed by applying pressure by a pressure device consisting of a 14cs tightening bolt 15, a disc spring 16, and a nut 17.

In the semiconductor stack 9 configured in this manner, the electrode conductor 12b is bent at an appropriate location and brought to the position of the electrode conductor 12a. On the other hand, 18 is a snubber unit in which a diode 5, a capacitor 6, and a resistor 7 are attached to the surface of a substrate 19 with screws, and an electrode 20a made of screws.

20b are attached to the substrate 21, and are stacked and attached to the frame 22 installed near the semiconductor stack 9. Furthermore, 23a and 23b are electric wires, and the element 10
It is connected to the heat sinks 11a and 11b at both ends of a and the electrodes 20a and 20b of the snubber unit 18.

However, in the semiconductor switch configured as described above, the elements 10a to 10c and the heat sinks lla to 1
When the number of laminated layers 1d increases, the total length of the laminated portions of the elements 10a to 10c, Heatons, and links 11a to 11d, and the electrode conductor 20b increases, resulting in a problem that the wiring inductance of the circuit increases. Furthermore, the wiring inductance between the semiconductor stack 9 and the snubber unit 18 is large, and the overvoltage generated during switching of the elements 10a to 10c cannot be sufficiently reduced, so there is a problem that the elements 10a to IOC are destroyed. .

(Issue 8 to be solved by the invention) As described above, in the conventional semiconductor switch, the wiring inductance of the circuit is large, and the wiring inductance between the semiconductor stack and the snubber unit is large. There was a problem in that the generated overvoltage could not be suppressed and the element would be destroyed.

The purpose of the present invention is to minimize the wiring inductance of the circuit, reduce the wiring inductance between the semiconductor stack and the snubber unit, suppress the overvoltage that occurs when switching the element, and prevent the destruction of the element. Our objective is to provide an extremely reliable high-speed semiconductor switch that is capable of

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides heat sinks on both sides of a flat semiconductor element, and further interposes input/output electrode conductors and insulating seats on the outside of the heat sinks. In a semiconductor switch consisting of a semiconductor stack to which input/output electrode conductors are connected, and a snubber unit consisting of a diode, a capacitor, and a resistor, the snubber unit is made into a printed circuit board, and the snubber unit is Flat electrode conductors are provided at both ends, and one of the heat sinks on both sides of the flat semiconductor element is connected to one electrode conductor of the snubber unit, and the other heat sink is connected to the flat conductor through an insulator. They are brought into close contact and extended to the other electrode conductor for connection.

(Function) Therefore, in the high-speed semiconductor switch of the present invention, the wiring inductance of the circuit can be kept small, and the wiring inductance between the flat semiconductor element and the snubber unit can be reduced. As a result, the overvoltage generated across the flat semiconductor element during switching can be suppressed to a small level, and destruction of the flat semiconductor element can be prevented.

(Embodiment) The present invention employs a semiconductor stack in which input and output electrode conductors are configured coaxially, and also forms a snubber unit into a printed circuit board to provide an electrode conductor, and a flat conductor is used to connect one of the heat sinks on both sides of the element. The snubber unit is connected to one electrode conductor of the snubber unit, and is connected from the other heat sink to the other electrode conductor by being brought into close contact with the flat conductor via an insulator.

Hereinafter, one embodiment of the present invention based on the above concept will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a front view showing a configuration example of a high-speed semiconductor switch according to the present invention, and FIG. 2 is a view taken along the line A--A in FIG. In FIGS. 1 and 2, the same elements as those in FIGS. 4 and 5 are denoted by the same reference numerals, and the explanation thereof will be omitted. Only the different parts will be described here.

In FIGS. 1 and 2, the electrode conductors 25a and 25b of the semiconductor stack 24 are configured coaxially to reduce wiring inductance. Further, 26 is a snubber unit, which has a diode 5, a capacitor 6, a resistor 7, and a flat electrode conductor 28a on both ends on the surface of a printed circuit board 27.
, 28b are attached to the frame 22 installed near the semiconductor stack 24 in a stacked manner. Furthermore, 2
9 is a flat conductor, one end of which connects to the heat sinks lla on both sides of the element 10a, and the heat sink lla on one side of the element 11b.
and is connected to the electrode conductor 28g of the snubber unit. In addition, one end of the flat conductor 30 is connected to the other heat sink llb.
It is brought into close contact with the flat plate conductor 30 via the insulator 31, and further brought into close contact with the back surface of the printed circuit board 27 of the snubber unit 26, and is extended and connected to the other electrode conductor 28b.

In the high-speed semiconductor switch of this embodiment configured as described above, the inductance of the circuit can be reduced by employing a semiconductor stack having a coaxial electrode configuration. In addition, the semiconductor stack 24 and the snubber unit 2
By making the wiring between 6 and 6 completely close together,
Wiring inductance between the semiconductor stack 24 and the snubber unit 26 can be reduced. This results in
The overvoltage generated across the element 10a during switching can be suppressed to a small level, and destruction of the element 10a can be prevented.

In the above embodiment, one end of the flat conductor 30 does not necessarily have to be in close contact with the back surface of the printed circuit board 27 of the snubber unit 26.

[Effects of the Invention] As explained above, according to the present invention, a heat sink is placed on both sides of a flat semiconductor element, and a laminate with an input/output electrode conductor and an insulating seat interposed on the outside thereof is tightened and pressurized, and the input/output is A semiconductor stack with connected electrode conductors, a diode,
In a semiconductor switch composed of a snubber unit consisting of a capacitor and a resistor, the snubber unit is made into a printed circuit board, flat electrode conductors are provided at both ends of the snubber unit, and one heat sink of the human sinks on both sides of the flat semiconductor element is formed. Since the heat sink is connected to one electrode conductor of the snubber unit with a flat conductor, and the other heat sink is connected to the flat conductor through an insulator and extended to the other electrode conductor, the wiring inductance of the circuit can be reduced. An extremely reliable high-speed semiconductor switch that minimizes the wiring inductance between the semiconductor stack, snubber, and unit, suppresses overvoltages that occur during device switching, and prevents device destruction. can be provided.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a high-speed semiconductor switch according to the present invention, FIG. 2 is a view taken along arrow A-A in FIG. 1, and FIG. 3 is a pulse generation using the high-speed semiconductor switch according to the present invention. FIG. 4 is a front view showing an example of the structure of a conventional semiconductor switch, and FIG. 5 is a view taken along the line B--B in FIG. 4. DESCRIPTION OF SYMBOLS 1... Capacitor, 2... Semiconductor element, 3... Pulse transformer, 4... Snubber circuit, 5... Diode, 6... Capacitor, 7... Resistor, 8... Closed Circuit, 9... Semiconductor stack, 10a, 10b, 10c
...Flat semiconductor element, lla, llb, llc, ll
d... Heat sink, 12a, 12b... Electrode conductor, 13-... Insulating seat, 14a, 14b, 14cm... Holding plate, 15... Tightening bolt, 16... Belleville spring, 17
...Natsuto, 18...Snubber unit, 19...
Substrate, 20a. 20b... Electrode, 22... Frame, 23a. 23b... Electric wire, 24... Semiconductor stack, 25a
. 25b... Electrode conductor, 26... Snubber unit, 2
7... Printed circuit board, 28a, 28b... Electrode conductor, 29... Flat plate conductor, 30... Flat plate conductor, 31
···Insulator.

Claims (1)

[Claims] A heat sink is placed on both sides of a flat semiconductor element, and a laminate with an input/output electrode conductor and an insulating pad interposed outside the heat sink is tightened and pressurized to form a semiconductor stack to which the input/output electrode conductor is connected. , a snubber unit consisting of a diode, a capacitor, and a resistor, the snubber unit is made into a printed circuit board, flat electrode conductors are provided at both ends of the snubber unit, and heat sinks on both sides of the flat semiconductor element are provided. One of the heat sinks is connected to one electrode conductor of the snubber unit with a flat conductor, and the other heat sink is connected to the flat conductor through an insulator and extended to the other electrode conductor. A high-speed semiconductor switch characterized by: