JP2001045764A - Power-supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of an excessive surge voltage caused by an external noise or the like by a method wherein a suppression means which suppresses high-voltage pulses generated by a noise creeping from a commercial power supply is installed at a choke coil which constitutes a line filter. SOLUTION: In this switching power-supply apparatus, an active filter and a line filter are provided. Two round lands 10, 11 by which respective terminals of inphase lines of common-mode choke coils are connected to wiring patterns on a printed-circuit board P are arranged so as to be separated from each other, and a discharging gap is constituted. At this time, a slit 12 is formed between the round lands 10, 11, protrusion parts 10a, 11a are formed, and constriction parts 13 are formed in pattern parts of connection lines. As a result, the generation of an excessive surge voltage caused by an external noise is suppressed. When a continuous discharge is generated in the discharging gap, the wiring partters are fused in the constriction parts 13, and it is possible to prevent a continuous discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply device having an active filter, and more particularly to a technique for coping with high voltage noise such as a lightning surge.

[0002]

2. Description of the Related Art Conventionally, switching power supplies have been widely used as DC power supplies for various electronic devices because of their advantages of small size, light weight, and high efficiency. A rectification method called a capacitor input type rectification method is usually used for an AC input portion of the switching power supply device. However, recently, with the spread of the switching power supply, generation of a harmonic current which is an adverse effect has been a problem. And is being regulated in Japan and overseas.

As a countermeasure against the harmonic current, a technique called an active filter for shaping an input current in a form proportional to an input voltage has attracted attention as a reliable method. However, this active filter is composed of a step-up chopper circuit or a step-down chopper circuit that shapes the waveform by controlling the switching element, and is added to the AC input section. There is a disadvantage that the level (terminal noise) increases.

In order to prevent this terminal noise from flowing out to the commercial AC power supply side, conventionally, several stages of line filters each including a capacitor and a coil are provided to cut off high-frequency noise. In this case, in the power supply device including the active filter, it is necessary to increase the capacitance of the capacitor constituting the active filter or the inductance of the coil, or to increase the number of stages of the line filter.

FIG. 11 is a circuit diagram showing a schematic configuration of a switching power supply device having an active filter.

In FIG. 11, an AC input of 50 Hz or 60 Hz input from a commercial AC power supply 1 is full-wave rectified by a diode bridge DB 1 via a line filter 2. The full-wave rectified AC input is supplied to the active filter 3.

In the active filter 3, the switching of the switching element Q1 is controlled according to the output power so that the input current waveform is a sine wave having the same phase as the input voltage waveform, and the peak value is changed according to the power amount. Is controlled. By the action of the active filter 3, a stable DC voltage is supplied to the converter 4, and by various known methods, as a DC output on the secondary side insulated from the primary side, which is the AC input side, by the transformer T, A desired voltage output is obtained.

Here, the line filter 2 is configured as a two-stage line filter, and the line filter on the diode bridge DB1 side is a high-frequency switching element Q
1. The line filter on the AC input side functions to cut off high-frequency noise lower than the high-frequency noise generated by Q1 and Q2. Not to return to the commercial AC power supply side, and also to block external high-frequency noise.

[0009]

However, when a high-voltage pulse surge (for example, a lightning surge applied to a commercial AC power supply) is externally applied to the power supply apparatus having such a configuration, the line filter 2 is not connected to the power supply apparatus. Since the two common mode choke coils L1 and L2 have variations in inductance between the coils, the voltage jumps up on one line, causes resonance with the next stage circuit, and the inductance of each winding and the inductance between them. Resonance occurs with the generated stray capacitance. For this reason, the active filter 3 in the subsequent stage,
Excessive surge voltage is applied to the semi-conductive switching elements Q1 and Q2 of the converter 4, and the semiconductor switching element Q
1, Q2, or cause malfunctions, and the semiconductor switching elements Q1, Q2
Even if no abnormalities occur, when the circuit is discharged due to an excessive surge voltage in the rectified circuit, an excessive surge current flows through the diode bridge DB1 and the diode bridge DB1 is broken.

The problem is that the greater the inductance of the choke coils L1 and L2 used in the line filter 2, the higher the filtering effect is, the larger the generated excessive surge voltage becomes. If the inductance is increased to suppress noise when an active filter or the like is provided,
The evil was getting bigger.

In particular, recently, with the development of data communication networks, emphasis has been placed on the electromagnetic environment, and the standard of immunity to external noise such as noise reduction and lightning surge generated by the power supply device itself has been increased. The request has become stronger.

The present invention has been made under such a background, and an object thereof is to suppress generation of an excessive surge voltage due to external noise or the like.

[0013]

In order to solve the above-mentioned problems, the present invention suppresses a high voltage pulse caused by noise intruding from a commercial power supply in a switching power supply device having a line filter and an active filter. The suppression means is provided on the choke coil constituting the line filter.

Further, in the present invention, the suppressing means arranges two lands for connecting each terminal of an in-phase line of a common mode choke coil constituting the line filter to a wiring pattern of a printed circuit board at a minute interval. The discharge gap thus formed is included.

In the present invention, the two lands may be:
It is composed of a round land.

Further, in the present invention, the suppressing means includes a slit formed between the two lands arranged at a minute interval.

Further, in the present invention, the suppressing means is formed on the two round lands by removing the round holes formed between the two round lands arranged at a minute interval. Including a projection.

Further, in the present invention, the resist is removed from at least the opposing portions of the two lands.

In the present invention, the suppressing means includes a constricted portion formed in the wiring pattern portion extending to the two lands.

Further, in the present invention, the suppressing means is respectively inserted into two lands for connecting each terminal of the common mode line of the common mode choke coil constituting the line filter to a wiring pattern of a printed circuit board. And two conductive eyelets, and the two eyelets have protrusions at opposing portions.

In the present invention, the suppression means is constituted by a constant voltage limiting element connected to each terminal of the same line of the common mode choke coil constituting the line filter.

In the present invention, the suppression means is provided for a common mode choke coil on an arbitrary line of the line filter.

In the present invention, the suppression means is provided for a common mode choke coil on each line of the line filter.

In the present invention, the suppression means is provided for each common mode choke coil constituting the line filter in a plurality of stages.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a line filter portion of a switching power supply device with an active filter to which the present invention is applied. This switching power supply device is actually a line filter 2A shown in FIG. It is composed of other circuits shown in FIG.

In FIG. 1, an AC power supply is connected to an input terminal T1.
And supplied from the commercial AC power supply 1 shown in FIG. The common mode choke coil L1 has a large inductance value and functions to remove common mode noise on a relatively low frequency side (100 kHz to 1 MHz) by coupling with the capacitors C2 and C3. The common mode choke coil L2 has a smaller inductance value than the common mode choke L1 and a small stray capacitance, and removes common mode noise on the relatively high frequency side (1 MHz to 10 MHz) by coupling with the capacitors C5 and C6. To work. Capacitor C1, C
Reference numerals 4 and C7 are provided to remove normal mode noise generated from the commercial AC power supply line and the power supply device.

[First Embodiment] In a first embodiment of the present invention, a pattern of a printed circuit board P is devised as shown in FIGS. The feature is that a discharge gap is formed. FIG. 2 is a plan view of the printed circuit board P, and FIG. 3 is an enlarged view of a portion surrounded by a broken circle in FIG.

As shown in FIGS. 2 and 3, the discharge gap is formed by two round lands 1 spaced apart from each other.
0 and 11 are formed. These two round lands 10 and 11 are arranged to face each other such that their centers are located on the same coaxial line, and of the axial portion connecting the centers of the round lands 10 and 11, the radius at which the round lands 10 and 11 face each other. In portions, the resist is removed as indicated by hatching to facilitate discharge.

The reason why the discharge gap is formed by the round land is that when the substrate pattern is formed by the etching process, the round land has a larger shape than the other wiring pattern portions.
This is because the accuracy of the position facing the discharge location and the like can be easily secured. Further, in order to prevent discharge on the surface of the printed circuit board P and prevent insulation deterioration of the board, the round land 10 is used.
A slit 12 is provided between the reference numerals 11. Further, protrusions 10a, 11a are provided at positions facing the round lands 10, 11.
Are formed. Although one line is shown in FIG. 3, the other line has the same configuration.

With this configuration, when an external high-voltage surge is applied to the choke coil L1, if a voltage equal to or greater than a certain value is generated at both ends of the choke coil L1, a discharge phenomenon occurs in the discharge gap. The discharge absorbs a high-voltage surge, and suppresses an excessive surge voltage due to the application of a high-voltage pulse that occurs in the conventional circuit. Therefore,
It is possible to eliminate the influence on the switching power supply unit including the active filter and the comparator circuit in the subsequent stage, and to prevent the destruction and malfunction of the semi-conductive switching elements Q1 and Q2.

When an experiment was conducted by applying a surge voltage waveform (maximum peak value 2 KV) specified as a lightning surge test, conventionally, as shown in FIG. On the other hand, in the above embodiment, an excessive vibration component was removed and the surge voltage applied to the circuit could be suppressed within 2 KV as shown in FIG.

Since the discharge gap is arranged between both terminals of the common mode line of the common mode choke coil L1, unlike the discharge gap arranged between the common mode choke coil L1 and the ground, even if a continuous surge voltage is applied, the discharge gap is not grounded. Although it is not necessary to consider the disconnection of the fuse due to dropping, in this embodiment, FIG.
As shown in FIG.
By providing the constricted portion 13 in the pattern portion of the connection line to the connection 11, even if a continuous discharge occurs in the discharge gap in the subsequent circuit due to a ground drop or the like, the wiring pattern is formed in the constricted portion 13. Are blown to prevent continuous discharge.

[Second Embodiment] In a second embodiment, the discharge gap is improved by modifying the pattern of the printed circuit board P as shown in FIGS. There is a characteristic in the point formed. FIG. 6 is a plan view of the printed circuit board, and FIG. 7 is an enlarged view of a portion surrounded by a broken line circle in FIG.

The discharge gap in the second embodiment is:
As shown in FIGS. 6 and 7, it is formed by two round lands 10 and 11 arranged apart from each other. These two round lands 10, 11 are arranged to face each other such that their centers are located on the same axis. Then, a round hole 14 having a diameter larger than the distance between the two round lands 10 and 11 is formed in the printed circuit board P around the middle point between the two round lands 10 and 11, whereby the round lands 10 and 11 are formed. Protrusions 10b and 11b are formed on each of the layers 11 to improve the discharge performance. In the present embodiment, the interval between the projections 10b and 11b formed on the round lands 10 and 11 by the round holes 14 is set to 2.5 mm.

In the present embodiment, as shown by hatching in FIG. 7, the resist at the opposing portions of the round lands 10 and 11 is deleted in a half-moon shape. Further, similarly to the first embodiment, the round lands 1 forming the discharge gap are formed.
Constriction 13 in the pattern portion of the connection line to 0, 11
Is provided. Although one line is shown in FIG. 7, the other line has the same configuration.

Experiments have confirmed that the same effects as those of the first embodiment can be obtained by such a configuration of the second embodiment.

[Third Embodiment] In the third embodiment, as shown in FIGS. 8 and 9, a discharge gap is formed by eyelets 15 and 16 for the portion indicated by reference numeral 6 in FIG. I have. 8 is a cross-sectional view of the printed circuit board P, and FIG. 9 is a plan view of the portion of FIG. 8 before the choke coil L1 is attached to the printed circuit board P.

Eyelets are originally inserted into lead holes to compensate for insufficient strength of the substrate when mounting electronic components such as large coils. In the present embodiment, the conductive eyelets 15 and 16 are used for the land portions of the choke coil L1, and the protrusions 15 are provided on the outer peripheral portions of the eyelets 15 and 16.
By forming a and 16a, the discharge property is improved.

The eyelets 15, 16 are arranged to face each other such that their centers are located on the same coaxial line. Further, as shown in FIG. 9, the projections 15a, 16a
Is formed only on one side of the printed circuit board P, but it is also possible to further improve the discharge performance by forming a projection on the opposite side.

[Fourth Embodiment] In the fourth embodiment,
As shown in FIG. 10, by connecting a voltage clamp element 17 having a constant voltage limiting function such as a varistor or an arrestor between lead terminals of the same line of the choke coil L1, a high voltage pulse is generated by the voltage clamp element 17. Clamping prevents high voltage pulses from passing through the choke coil L1, thereby suppressing the occurrence of excessive high voltage surge.

In this embodiment, although the number of components is increased as compared with the first to third embodiments, the voltage level to be clamped can be varied, so that the occurrence of an excessive high voltage surge can be suppressed more reliably. Will be able to

The present invention is not limited to the above embodiment. For example, the first to fourth excessive surge voltage suppressing mechanisms can be provided for each of a plurality of choke coils. . Further, the first to fourth excessive surge voltage suppressing mechanisms may be provided only on one line.

[0044]

As described above, according to the present invention,
In the switching power supply device including the line filter and the active filter, the suppression means for suppressing the high voltage pulse caused by the noise invading from the commercial power supply is provided in the choke coil constituting the line filter. It is possible to suppress the occurrence of an excessive surge voltage due to this.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a line filter to which the present invention is applied.

FIG. 2 is a plan view of a printed circuit board provided with an excessive surge voltage suppression mechanism according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a portion circled in FIG. 2;

FIG. 4 is a waveform diagram showing an excessive surge voltage that has conventionally occurred.

FIG. 5 is a waveform chart showing a surge voltage suppressed by the present invention.

FIG. 6 is a plan view of a printed circuit board provided with an excessive surge voltage suppression mechanism according to a second embodiment of the present invention.

FIG. 7 is an enlarged view of a portion circled in FIG. 6;

FIG. 8 is a sectional view of a printed circuit board showing an excessive surge voltage suppressing mechanism according to a third embodiment of the present invention.

FIG. 9 is a plan view of a portion shown in FIG. 8 before a choke coil is attached.

FIG. 10 is a circuit diagram showing an excessive surge voltage suppression mechanism according to a fourth embodiment of the present invention.

FIG. 11 is a circuit diagram showing a schematic configuration of a switching power supply device provided with a conventional active filter.

[Explanation of symbols]

2A: Line filter, 3: Active filter, 4:
Converters 10, 11: round land, 10a, 11a,
10b, 11b, 15a, 16a: projecting portion, 12: slit, 13: constricted portion, 14: round hole, 15, 16: eyelet, 17: voltage clamp element, L1, L2: common mode choke coil, P: printed circuit board , Q1, Q2: switching elements.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 37/00 H01F 37/00 NK H02M 1/12 H02M 1/12 7/06 7/06 H

Claims (12)

[Claims] 1. A switching power supply device having a line filter and an active filter, wherein a suppression means for suppressing a high-voltage pulse caused by noise entering from a commercial power supply is provided in a choke coil constituting the line filter. A power supply device characterized by the above-mentioned. 2. The suppression means is formed by arranging two lands for connecting each terminal of the same line of a common mode choke coil constituting the line filter to a wiring pattern of a printed circuit board at a minute interval. 2. The power supply device according to claim 1, further comprising a discharge gap. 3. The power supply device according to claim 2, wherein the two lands are configured by round lands. 4. The power supply device according to claim 2, wherein said suppressing means includes a slit formed between said two lands arranged at a minute interval. 5. The restraining means includes: a round hole formed between the two round lands arranged at a minute interval; and a projection formed on the two round lands by being removed by the round hole. The power supply device according to claim 3, further comprising: 6. The power supply device according to claim 2, wherein a resist is removed from at least a portion of the two lands opposed to each other. 7. The power supply device according to claim 2, wherein said suppressing means includes a constricted portion formed in a wiring pattern portion reaching said two lands. 8. The control means according to claim 1, wherein each of the terminals of the common mode choke coil constituting the line filter is connected to two lands for connecting a terminal of the same line to a wiring pattern of a printed circuit board. 2. The power supply device according to claim 1, wherein the power supply device is constituted by two eyelets, and has a projection at a portion facing the two eyelets. 9. The power supply device according to claim 1, wherein said suppressing means is constituted by a constant voltage limiting element connected to each terminal of the common mode choke coil constituting said line filter. . 10. The power supply device according to claim 1, wherein the suppression unit is provided for a common mode choke coil on an arbitrary line of the line filter. 11. The power supply device according to claim 1, wherein said suppression means is provided for a common mode choke coil on each line of said line filter. 12. The power supply device according to claim 1, wherein said suppression means is provided for each common mode choke coil constituting said line filter in a plurality of stages.