JP2011060568A - Power source for driving magnetron - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source for driving a magnetron capable of mounting a printed circuit board on a mounting plate without fracturing patterns. <P>SOLUTION: The power source for driving a magnetron has the printed circuit board, an inverter circuit including a semiconductor switching element for converting power of a power source into high frequency and a capacitor on the printed circuit board, a step-up transformer for converting the power made at high frequency with the inverter circuit into high voltage and supplying the power to the magnetron which requires high voltage, and a heat-radiating fin for cooling heat generated from the semiconductor switching element. Thus, the printed circuit board can be mounted on the mounting plate without fracturing the patterns on the printed circuit board since a reinforcing member supporting between the step-up transformer and the heat-radiating fin is provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetron driving power source using a magnetron such as a microwave oven as a load.

  A conventional magnetron driving power supply will be described with reference to the drawings. FIG. 6 is a front view showing an appearance of a conventional magnetron driving power source. FIG. 7 is an enlarged view of the main part showing the solder surface of the mounting portion of the semiconductor switching element on the printed circuit board of the same power source. FIG. 8 is a block diagram showing a circuit of the same power source.

  In these drawings, the magnetron driving power source includes a unidirectional power source unit 1, an inverter circuit unit 2, a driving circuit 3, a high voltage rectifier circuit 4, and a magnetron 5. The unidirectional power supply unit 1 is a low-pass filter circuit including a diode bridge 102 that full-wave rectifies an AC power supply from a commercial power supply 101, a choke coil 103, and a capacitor 104, and a role of a filter for high-frequency switching operation of the inverter circuit unit 2 To fulfill.

  The inverter circuit unit 2 includes a resonant capacitor 201, a semiconductor switching element 202, a commutation diode 203, and a step-up transformer 204. The switching element 202 performs a switching operation according to a switching control signal of 20 to 50 kHz supplied from the drive circuit 3. Thereby, a high frequency voltage is generated in the primary winding of the step-up transformer 204.

  The high voltage rectifier circuit 3 includes capacitors 401 and 402 and diodes 403 and 404. The high voltage rectifier circuit 3 generates a high voltage DC voltage by rectifying the voltage generated in the secondary winding of the step-up transformer 204 by a half-wave voltage doubler. , Applied to the magnetron 5.

  An AC voltage for the heater is also applied to the magnetron 5 from the heater winding of the step-up transformer 204. The magnetron 5 is in a state where it can oscillate when the AC voltage for the heater is applied by being heated side by side, and when a high-voltage current voltage is applied in this state, electromagnetic energy is generated.

  The semiconductor switching element 202 of the inverter circuit unit 2 includes radiating fins 6 for cooling the heat generation as shown in FIG. Moreover, the radiation fin 6 and the step-up transformer 204 are located on the side surface of the printed board.

  Furthermore, two pattern examples of an enlarged view of the main part when the lead terminal portion of the semiconductor switching element 202 is viewed from the solder surface side are shown in FIGS. As shown in FIGS. 7A and 7B, slits S1, S2, and S3 are provided in the printed circuit board of the lead terminals of the gate G, the emitter E, and the collector C of the semiconductor switching element 204.

  This is because the semiconductor switching element 204 generates a large amount of heat, and a thermal stress is generated on the printed circuit board through the lead wire, so that this thermal stress is reduced. The configuration of the conventional magnetron driving power source is described in Patent Document 1.

Japanese Patent No. 3986462

  However, in such a configuration, when the magnetron driving power source is mounted on the set (inverter mounting plate), if it is mounted between the step-up transformer 204 and the heat radiating fins 6, an excessive amount to the slit of the semiconductor switching element 202 is excessive. There is a problem that stress is generated, the pattern of the semiconductor switching element 202 is torn, and the semiconductor switching element 202 is broken.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a magnetron driving power source that enables an inverter to be attached without a substrate pattern being torn.

  In order to solve the conventional problems, a magnetron driving power supply according to the present invention includes a printed circuit board, an inverter circuit including a semiconductor switching element and a capacitor for converting power of the power supply to a high frequency on the printed circuit board, A step-up transformer that converts high-frequency power generated by the inverter circuit into a high voltage and that supplies power to a magnetron that requires high voltage; and a heat radiation fin that cools the heat generated by the semiconductor switching element. By providing a reinforcing member that supports the printed circuit board, it is possible to attach the printed circuit board without tearing the pattern of the printed circuit board.

  The magnetron driving power source according to the present invention can attach the printed circuit board to the mounting plate without tearing the pattern of the printed circuit board by attaching a reinforcing member between the step-up transformer and the radiation fin.

Sectional drawing of the reinforcing member in Embodiment 1 of this invention, and side view of the reinforcing member The front view which shows the external appearance of the power supply for magnetron drive in the form of this invention The front view which shows the structure which provided the semiconductor switching element in the radiation fin in Embodiment 1 of this invention The front view which shows the structure which provided the semiconductor switching element and the diode bridge in the radiation fin in Embodiment 2 of this invention The front view which shows the structure which provided the two semiconductor switching elements and the diode bridge in the radiation fin in Embodiment 3 of this invention Front view showing the appearance of a magnetron driving power source in a conventional magnetron driving power source The main part enlarged view of the lead terminal part of the semiconductor switching element seen from the solder side of the printed circuit board in the conventional magnetron driving power supply Block configuration diagram showing a conventional magnetron drive power supply circuit

  According to a first aspect of the present invention, there is provided a printed circuit board, an inverter circuit including a semiconductor switching element and a capacitor for converting the power of the power source to a high frequency on the printed circuit board, and converting the high frequency power by the inverter circuit into a high voltage. And a step-up transformer that supplies power to a magnetron that requires high pressure, a heat radiation fin that cools heat generated by the semiconductor switching element, and a reinforcing member that supports the space between the step-up transformer and the heat radiation fin. .

Thereby, the said printed circuit board can be attached to an attachment board, without the pattern of a printed circuit board tearing.

  According to a second invention, in the first invention, the reinforcing member presses the core of the step-up transformer. Thereby, the vibration of the core can be suppressed.

  According to a third invention, in the first invention, the reinforcing member and the step-up transformer are thermally melted and fixed. Thereby, the reinforcing member and the core can be easily fixed.

  According to a fourth invention, in any one of the first to third inventions, the radiating fin for cooling the heat generation of the semiconductor switching element includes both the semiconductor switching element and a diode bridge for rectifying the commercial power source. Thereby, both a semiconductor switching element and a diode bridge can be cooled.

  According to a fifth invention, in any one of the first to third inventions, the radiating fin for cooling the heat generated by the semiconductor switching element includes both at least two semiconductor switching elements and a diode bridge for rectifying the commercial power source. It is. Thereby, both a semiconductor switching element and a diode bridge can be cooled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 (a) is a front view of a reinforcing member for a magnetron driving power source according to the first embodiment of the present invention, FIG. 1 (b) is a side view of the reinforcing member, and FIG. FIG. 3 is a front view showing a configuration in which a semiconductor switching element is provided on a heat radiating fin.

  The magnetron driving power source according to the present embodiment has a configuration in which a step-up transformer 204 and a heat radiating fin 6 are arranged on the side surface of the printed circuit board 7 on the printed circuit board 7 and a reinforcing member 8 is provided between the printed circuit board 7 to prevent pattern tearing. ing.

  The step-up transformer and the reinforcing member can be easily fixed by heat melting. Further, since the reinforcing member 8 is configured to hold down the core 9 of the step-up transformer 204, vibration of the core 9 can be suppressed.

  As described above, the reinforcing member 8 is configured to be inserted between the step-up transformer 204 and the heat radiating fins 6, so that when the magnetron driving power source is mounted on the set (inverter mounting plate), Even if it is mounted with the heat radiating fins 6 between them, even if there is a slit in the semiconductor switching element 202, the pattern of the semiconductor switching element portion 202 can be inserted without tearing.

(Embodiment 2)
FIG. 4 is a view showing the radiation fin 6 according to the second embodiment of the present invention, in which the type of the radiation fin according to the first embodiment shown in FIG. 2 is changed.

  As shown in FIG. 4, the radiation fin 6 that cools the heat generated by the semiconductor switching element 202 is also provided in the configuration of the radiation fin when both the semiconductor switching element and the diode bridge 102 that rectifies the commercial power supply are provided. In the same manner as in FIG. 1, the reinforcing member 8 can be inserted between the step-up transformer 204 and the radiation fin 6.

(Embodiment 3)
FIG. 5 is a view showing the radiation fin 6 according to the second embodiment of the present invention, in which the type of the radiation fin according to the first embodiment shown in FIG. 2 is changed.

  As shown in FIG. 5, in the configuration of the radiation fin 6 in the case where both the at least two semiconductor switching elements 202 and 205 and the diode bridge 102 for rectifying the commercial power supply are provided, the step-up transformer 204 is also provided as in the first embodiment. The reinforcing member 8 can be inserted between the heat radiating fins 6.

  Although various embodiments of the present invention have been described above, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art can make modifications and applications based on the description and well-known techniques. This is also the scope of the present invention, and is included in the scope for which protection is sought.

  As described above, the magnetron driving power source according to the present invention can be applied to a microwave heating apparatus such as a microwave oven, and by attaching a reinforcing member between the step-up transformer and the heat radiating fin, The printed circuit board can be attached to the mounting plate without tearing the pattern.

DESCRIPTION OF SYMBOLS 1 Unidirectional power supply part 2 Inverter circuit part 3 Drive circuit 4 High voltage rectifier circuit 5 Magnetron 6 Radiation fin 7 Printed circuit board 8 Reinforcement member 9 Core 101 Commercial power supply 102 Diode bridge 103 Choke coil 104 Capacitor 201 Resonance capacitor 202 Semiconductor switching element 203 Commutation Diode 204 Step-up transformer 205 Semiconductor switching element 401, 402 Capacitor 403, 404 Diode

Claims (5)

A printed circuit board, an inverter circuit including a semiconductor switching element and a capacitor for converting the power of the power source to a high frequency on the printed circuit board, and converting the high frequency power generated by the inverter circuit to a high voltage and requiring a high voltage A magnetron driving power source comprising a step-up transformer that supplies electric power to the magnetron, and a radiation fin that cools heat generated by the semiconductor switching element, and a reinforcing member that supports the gap between the high-voltage transformer and the radiation fin. The magnetron driving power source according to claim 1, wherein the reinforcing member has a configuration for pressing a core of a step-up transformer. The magnetron driving power source according to claim 1, wherein the reinforcing member is configured to thermally melt and fix the reinforcing member and the step-up transformer. The magnetron driving power source according to any one of claims 1 to 3, wherein the radiating fin includes both the semiconductor switching element and a diode bridge that rectifies a commercial power source. The magnetron driving power source according to any one of claims 1 to 3, wherein the radiating fin includes a diode bridge that rectifies at least two semiconductor switching elements and a commercial power source.

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