JP2002300781A - Large current push-pull step-up circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a push-pull step-up power supply circuit which has a large capacity with the secondary side output. SOLUTION: This large current push-pull step-up circuit has a first plate-like electrode 1 of an approximately rectangular shape having a region disposing a push-pull transformer 20 in the center and terminal parts each mounting capacitors on both sides, a pair of second plate-like electrodes 2 and 3 each of an approximately rectangular shape having approximately a half area of the first plate-like electrode and having each a terminal connecting field-effect transistors and Zener diodes on one side, a third plate-like electrode 4 of an approximately rectangular shape having approximately same area of the upper plate part of the first plate-like electrode and having terminal parts each connecting to field-effect transistors, capacitors, and Zener diodes on both sides, and electric-insulation sheets 8. The first, the second and the third plate-like electrodes are electrically insulated between each other by the electric-insulation sheet 8 and integrally fixed with locking elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plate-like electrode structure of a push-pull type booster circuit used in a booster circuit for boosting a low DC voltage to a high DC voltage.

[0002]

2. Description of the Related Art In a push-pull type booster circuit, a large current flows on a low voltage primary side in order to ensure a high voltage output on a secondary side. For this reason, in a conventional configuration such as Japanese Patent Application No. 2000-218151 filed by the present applicant, a spike voltage caused by a back electromotive force generated when the switching element is turned off increases due to a large inductance of the primary side current circuit, The switching loss increases, the required capacity of the snubber circuit increases, the conversion efficiency between the primary input and the secondary output decreases, and the performance of the booster power supply circuit as a whole has deteriorated.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a push-pull type booster circuit, which minimizes a primary current path which causes a large current, minimizes an inductance of the primary current circuit, and generates a counter electromotive force generated when a switching element is turned off. Reduce power-induced spike voltage, reduce switching loss, reduce required capacity of snubber circuit, improve conversion efficiency between primary input and secondary output, and improve overall boost power supply circuit performance. Another object is to increase the capacity of the secondary side output.

[0004]

In order to solve the above-mentioned problems, the invention according to claim 1 has a substantially rectangular shape having a centrally disposed area for arranging a push-pull transformer and terminal parts for mounting capacitors on both sides. A first plate-like electrode, a pair of second plate-like members each having a terminal portion for connecting a field effect transistor and a Zener diode on one side and having a substantially rectangular shape and an area approximately half the area of the first plate-like electrode. A third plate-like electrode having an electrode, a terminal portion for connecting a field effect transistor, a capacitor, and a zener diode on both sides, having a substantially rectangular shape, and having an area approximately equal to the upper portion of the first plate-like electrode; An insulating sheet is provided, a pair of second plate-like electrodes is arranged below the first plate-like electrode, and a third plate-like electrode is arranged below the second plate-like electrode. 2nd and 3rd plates The plates are electrically insulated by an electric insulating sheet, and the first, second, and third plate electrodes are integrally fixed by a fastening element. Structure and

According to a second aspect of the present invention, the electronic elements arranged in the first, second, and third plate-like electrode structures are arranged at geometrically symmetric positions.

According to a third aspect of the present invention, the fastening element for fixing the first, second, and third plate electrodes is formed of an electrically insulating material.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment described below is an example, and according to a person having ordinary skill in the art, other embodiments may be used without departing from the technical scope of the present invention. Is easy to implement.

FIG. 1 shows a push-pull type booster power supply circuit according to the present invention. In FIG. 1, a primary circuit 100 surrounded by a dotted line includes a primary winding 20-2 of the push-pull transformer 20, a power supply 30 such as a 12 V battery connected to an intermediate lead portion B + of the primary winding, and a power supply for the B + line. An electrolytic capacitor 7 is connected to both ends of the capacitor 30 in parallel with each other in number m (total 2 m). Further, the primary circuit 10
0 indicates that n field effect transistors 5 and zener diodes 6 are connected in parallel between the C1 line and the B + line of the primary winding. The source S of the field effect transistor 5 is connected to the B + line, the drain D is connected to the C1 line, the gate G is connected to a control circuit (not shown), the cathode of the Zener diode 6 is connected to the C1 line, and the anode is connected to the B + line. . As shown, the primary winding C2
The same applies between the line and the B + line. The output of the secondary winding 20-3 via the core 20-1 of the push-pull transformer 20 is supplied to the load 50 via the rectifying and smoothing circuit 40 including a rectifying element and a capacitor.

A total of 2 m electrolytic capacitors 7 are divided into 2 m capacitors to reduce the internal impedance of the battery power supply 30 and absorb noise, and to cope with large currents. In the embodiment, m = 9. A total of 2n Zener diodes 6 constitute a snubber circuit. Further, a total of 2n field effect transistors 5 are controlled by a control circuit (not shown) to perform switching. Each of the Zener diode 6 and the field effect transistor 5 is divided into 2n pieces to cope with a large current. In the embodiment, n = 8
It is.

FIGS. 2 and 3 show a power supply circuit structure. A description will be given with reference to FIGS. The plate electrode structure of the power supply circuit includes an upper plate electrode 1, a pair of intermediate plate electrodes 2 and 3, and a lower plate electrode 4. The plate electrodes are insulated by an electric insulating sheet 8 made of epoxy resin or the like, and are integrally fixed by a plurality of insulating bolts 10 made of acrylic resin or the like. The pair of intermediate plate electrodes 2 and 3 are arranged such that the terminal portions 2-1 and 3-1 on one side are exposed to the left and right of the plate electrode.

The power source 30 is provided with screws and the like in the terminal portions 1-1 and 4-2 so that the upper plate electrode 1 has a positive potential and the lower plate electrode 4 has a negative potential. Used and electrically and mechanically connected. Push-pull transformer 20
Is a pair of E-type ferrite cores facing each other, a primary winding is wound in the center, the outer periphery of the primary winding is insulated with an insulating sheet or the like, and a secondary winding is placed on the upper layer of the insulating sheet or the like. It is a configuration in which the layers are wound. The winding ends C1, C2 of the primary winding are:
Terminals each capable of being screwed are electrically and mechanically connected. The terminal that can be screwed is electrically and mechanically connected to the intermediate lead portion B + of the primary winding. The lead portion 20-3 of the secondary winding is electrically and mechanically connected to a secondary-side smoothing circuit (not shown). Push-pull transformer 2
No. 0 electrically and mechanically connects the intermediate lead portion B + of the primary winding to a predetermined position of the upper plate electrode 1 with a bolt, and one end C1 of the primary winding is connected to the intermediate plate electrode 2 with a screw.
The other end C2 of the primary winding is also electrically and mechanically connected to a predetermined position of the intermediate plate electrode 3 in the same manner.

FIG. 4 shows a single state of the upper plate-like electrode 1, and FIG.
6 shows a single state of the pair of intermediate plate electrodes 2 and 3, and FIG. 6 shows a single state of the lower plate electrode 4. The upper plate-like electrode 1
A terminal portion 1-1 on one side, a screw hole for electrically and mechanically fixing the terminal portion B + of each primary winding of the transformer 20, and a rectangular through hole through which the terminal portions C1 and C2 are inserted; A circular or rectangular through-hole or screw hole (screw portion) such as a screw hole for integrally fixing the three plate-like electrodes 1, 2, and 3 is provided. The pair of intermediate plate-shaped electrodes 2 or 3 have the same shape, are provided with terminal portions 2-1 or 3-1 on one side, and are provided with similar through holes or screw holes (screw portions).
The lower plate-shaped electrode 4 has a terminal portion 4-2 on one side and a terminal portion 4-1 on both sides, and has a similar through hole or screw hole (screw portion).

Returning to FIG. 2 and FIG. First, in FIG. 2, the terminals arranged on the left and right of the plate-like electrode are:
Left and right lower plate electrode terminals 4-
1. Terminal 2-1 or 3-1 of intermediate plate electrode 2 or 3
Are alternately arranged. In the circuit structures shown in FIGS. 2 and 3, the terminals and the electronic elements described below are arranged symmetrically (the source S, the drain D, and the gate G of the field-effect transistor 5). Due to the foot arrangement, the arrangement of the electronic elements is shifted left and right by one terminal up and down in the drawing, but this is not an essential problem and can be regarded as a left and right symmetric arrangement.) The following electronic device arrangement connection
Only the right side facing the figure will be described, but the same applies to the left side.

The field effect transistor 5 is disposed outside the terminals 2-1 and 4-1 of the plate electrode, the drain D is connected to the terminal 2-1 of the intermediate plate electrode 2, and the source S is connected to the lower plate electrode 4.
The terminal 4-1 is electrically connected to the terminal 4-1 by solder or the like and mechanically connected. The gate G is connected to a control circuit (not shown). The Zener diode 6 is connected to the terminal 2-
1 and 4-1. The cathode is electrically and mechanically connected to the terminal 2-1 together with the drain D by soldering or the like, and the anode is similarly connected to the terminal 4-1 together with the source S. The electrolytic capacitor 7 has an upper plate electrode 4
An upper plate electrode 4 and a lower plate electrode terminal 4
-1 is similarly connected. The field-effect transistor 5 is contacted and / or fixed to a heat sink via an electrically insulating and thermally conductive resin such as silicon for cooling.

As is clear from the above description (particularly in FIG.
), The three plate-shaped electrodes are arranged symmetrically to the left and right, and the plurality of mounted electronic elements are arranged symmetrically with respect to the transformer 20 arranged at the center of the electrodes. Therefore, the geometric distance between the plurality of electronic elements and the primary winding of the transformer arranged on the substantially rectangular plate electrode (for example, the distance between the terminal C1 and the plurality of right electronic elements) is minimized. It is an arrangement configuration.

[0016]

As is apparent from the above description, according to the first aspect of the present invention, the primary current path of the push-pull type booster circuit is formed by the upper plate electrode 1, the pair of intermediate plate electrodes 2 or 3, And a three-layered electrode (bus bar) composed of the lower plate-shaped electrode 4 and the left and right symmetrical arrangement of the electronic elements, thereby minimizing the primary current path and reducing the inductance associated with the primary current circuit. This minimizes the switching element off-spike voltage, reduces switching losses, and improves efficiency.
The snubber circuit includes a source S of the field effect transistor 5,
A sufficient effect is obtained only by connecting the Zener diode 6 between the drains D, and a circuit in which a capacitor is connected in series with the parallel connection of the resistor and the diode of the conventional configuration is connected between the source S and the drain D of the field effect transistor 5. This configuration is unnecessary. As a result, the power consumption in the snubber circuit is
Significant reduction is achieved, and the power conversion efficiency (overall performance) between primary and secondary circuits, especially at low loads, is improved. According to the second aspect of the present invention, the electronic elements are arranged with geometric symmetry, and a circuit analysis including an inductance can be easily performed, thereby increasing the degree of freedom in circuit design. Furthermore, according to the third aspect of the present invention, by fixing the three plate-shaped electrodes by the fastening element formed of an electrically insulating material, a special fixing element and electrical insulation between the plate-shaped electrodes are considered. Without the need for assembly, assembly work can be easily performed, and assembly on a continuous production line becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a push-pull type booster power supply circuit showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a push-pull type step-up power supply showing one embodiment of the present invention.

FIG. 3 is a partial sectional view of the configuration diagram shown in FIG. 2;

FIG. 4 is a front view of an upper plate electrode.

FIG. 5 is a front view of an intermediate plate electrode.

FIG. 6 is a front view of a lower plate-like electrode.

[Explanation of symbols]

 Reference Signs List 100 Primary circuit of push-pull type booster power supply circuit 1 Upper plate electrode 2, 3 Intermediate plate electrode 4 Lower plate electrode 5 Field effect transistor 6 Tse diode 7 Electrolytic capacitor 8 Electrical insulating sheet 10 Electrical insulating fastening element

Claims (3)

[Claims] 1. A substantially rectangular first plate-like electrode (1) having a central area where a push-pull transformer (20) is arranged and terminals for mounting capacitors on both sides, and a field effect transistor on one side. , And a pair of second plate-like electrodes (2) and (3) each having a substantially rectangular shape having a terminal portion for connecting the Zener diode and having an area approximately half that of the first plate-like electrode. A third plate-shaped electrode (4) having a terminal portion for connecting a transistor, a capacitor, and a Zener diode and having a substantially rectangular shape and having an area approximately equal to the upper portion of the first plate-shaped electrode; ), A pair of second plate-like electrodes (2) and (3) are disposed below the first plate-like electrode (1), and a third plate-like electrode is disposed below the second plate-like electrode. (4) is arranged, these first, second and third plates A large current push-pull type booster circuit characterized in that the first, second and third plate-like electrodes are electrically insulated from each other by an electric insulating sheet (8) and the first, second and third plate-like electrodes are integrally fixed by a fastening element. Plate-shaped electrode structure. 2. The electronic device according to claim 1, wherein the electronic elements arranged in the first, second, and third plate-like electrode structures are arranged at geometrically targeted positions. 3. The device according to claim 1, wherein the fastening element for fixing the first, second, and third plate-shaped electrodes is formed of an electrically insulating material.