JPH0591743A - Power converter - Google Patents

Abstract

PURPOSE:To reduce in size an entire power converter and to provide noise prevention and a mass production by reducing in size components to be used, separating the components to primary and secondary sides, and regularly mounting them. CONSTITUTION:Eight DC/DC converters 271-27g having the same circuit configurations on a bottom board of a chassis 51 are separated into primary and secondary sides, regularly arranged and mounted. Input and output temminals of the converters are respectively connected in series to constitute one DC/DC converter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter using a plurality of DC-DC converters.

[0002]

2. Description of the Related Art For example, a power converter using a forward converter is known as a power converter used in a discharge lamp lighting device. This power converter takes in an AC power supply through a fuse and a filter circuit, converts it into a DC power supply using a full-wave rectifier circuit and a smoothing capacitor, and uses a switching transistor, a transformer, a choke coil, a diode, A forward converter including a control circuit for driving and controlling a capacitor and a transistor is connected and configured.

Conventionally, when such a power converter is arranged on a wiring board and assembled in a chassis, it is shown in FIG.
, (B). That is, the insulating film 2 is attached on the chassis 1, and the wiring board 3 is arranged above the insulating film 2. The fuse 4, the filter circuit component 5, the switching transistor 7 attached to the heat sink 6, the control circuit component 8, the transformer 9, the choke coil 10, the diodes 11 and 12, the capacitor 13, the control circuit component are provided on the wiring board 3. 14 are arranged and the chassis 1
Lead wires 15a, 1 connected to the input terminal from one end side of the
5b, a lead wire 16 connected to the output terminal from the other end
a and 16b are pulled out.

[0004]

Although such a conventional device uses a relatively small number of circuit components, the individual components are large due to the large withstand voltage and capacitance of each component, which results in a large overall configuration. was there. In addition, since the individual components are large, the placement of the components on the wiring board 3 is restricted, and the components that should be adjacent to each other cannot be placed in a short distance. Further, there is no regularity in the wiring of the individual components. There was a problem that signal noise and radio noise were easy to get in because the output side and the output side were mixed. Furthermore, since it is difficult to carry out regular wiring, there is a problem that automation of mounting is difficult and mass production cannot be performed.

Therefore, according to the present invention, each component to be used can be miniaturized, and the primary side and the secondary side can be separately and regularly mounted on the wiring board, so that the device can be miniaturized and signal noise and noise can be reduced. An object of the present invention is to provide a power conversion device that can sufficiently cope with radio noise and can be easily mass-produced.

[0006]

According to the present invention, a plurality of DC-DC converters having the same or substantially the same circuit configuration are mounted on a wiring board by separating the primary side and the secondary side and arranging them regularly. Then, the input terminal and the output terminal of each DC-DC converter are connected in series or in parallel or in a combination of series and parallel to form one DC-DC converter.

[0007]

In the present invention having such a configuration, one DC-DC converter is constructed by connecting the input terminals and output terminals of a plurality of DC-DC converters in series or in parallel or in combination of series and parallel. The breakdown voltage and capacity of each circuit component can be reduced. Further, since a plurality of DC-DC converters having the same or substantially the same circuit configuration are separated from the primary side and the secondary side and are regularly arranged and mounted, the wiring distance is short and the wiring is neat. Furthermore, it becomes possible to automate the mounting of circuit components.

[0008]

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

FIG. 1 is a diagram showing a circuit configuration, which includes 21a and 2a.
1b is an input terminal connected to an AC power supply. A power supply circuit section 22 is connected between the input terminals 21a and 21b. The power supply circuit unit 22 includes a fuse 23, a coil 24,
It is composed of a capacitor 25 and a full-wave rectifier circuit 26.
Between the output terminals of the full-wave rectifier circuit 26, for example, a series circuit of input terminals of eight DC-DC converters 271, 272, ... 278 is connected.

Each of the DC-DC converters 271-27
8 is provided with a smoothing capacitor 31, and this smoothing capacitor 3
A primary side input terminal is provided between both ends of 1 and a series circuit of a diode 32 and a constant voltage diode 33 and a series circuit of a primary winding of a transformer 34 and a field effect transistor 35 are connected in parallel across both ends. ing. A capacitor 36 is connected in parallel between both ends of the constant voltage diode 33, and a control circuit 37 for switching the transistor 35 is connected between both ends of the capacitor 36. The smoothing capacitors 31 of the DC-DC converters 271 to 278 are connected in series, and both ends of the series circuit are connected to the output terminal of the full-wave rectifier circuit 26. In the transformer 34, the primary winding and the secondary winding are insulated from each other, and the secondary winding has a capacitor 3 via a diode 38.
9 are connected in parallel. Then, the capacitors 39 of the DC-DC converters 271 to 278 are connected in series,
Both ends of the series circuit are connected to output terminals 40a and 40b, respectively.

Each circuit component forming such a circuit is incorporated in the chassis 51 as shown in FIGS. 2 (a) and 2 (b). That is, the lead wires 52a and 52b connected to the input terminals 21a and 21b from one end of the chassis 51.
And output terminals 40a, 40 from the other end side.
Lead wires 53a and 53b connected to b are drawn out.

The upper surface of the bottom of the chassis 51 is insulated, and the upper surface also serves as a circuit board. Then, on the input terminal side on the board, the components of the fuse 23, the coil 24 and the capacitor 25, which constitute the power supply circuit section 22, and the full-wave rectification circuit 26 are arranged.

On the output terminal side of the power supply circuit section 22, the components of the eight DC-DC converters 271 to 278 are mounted such that the primary side and the secondary side are separated and regularly arranged. .. That is, in each of the DC-DC converters 271 to 278, a relatively large transformer 34 is mounted in a substantially central portion, and a field effect transistor 35, a smoothing capacitor 31, a diode 32, and a constant voltage which constitute a primary side below the transformer 34. Diode 33, capacitor 3
6. A circuit component 54 including a control circuit 37 is mounted, and a diode 38 constituting a secondary side is provided above the transformer 34.
The circuit component 55 of the capacitor 39 is mounted.

In this embodiment having such a structure, the voltage generated at the output terminal of the full-wave rectifier circuit 26 is divided by the series circuit of eight smoothing capacitors 31. Therefore, the voltage applied to each smoothing capacitor 31 is the full-wave rectifier circuit 26.
1/8 of the output voltage from

Each DC-DC converter circuit 271 ...
In 278, a high frequency voltage is generated in the secondary winding of the transformer 34 by the on / off operation of the field effect transistor 35, and the high frequency voltage is rectified via the diode 38 and smoothed by the capacitor 39. Thus each DC-
A DC voltage is generated across the capacitors 39 of the DC converter circuits 271 to 278.

However, each DC-DC converter circuit 27
Between the ends of the series circuit of the capacitors 39 of 1 to 278, a direct current voltage which is eight times the direct current voltage generated between the ends of the individual capacitors 39 is generated. Thus each DC-
Output terminals 40a and 40b even if the voltage generated in the capacitor 39 of the DC converter circuits 271 to 278 is relatively low.
The voltage generated between them is sufficiently high. Therefore, if a discharge lamp is connected as a load between the output terminals 40a and 40b, the discharge lamp can be easily turned on.

In this way, each DC-DC converter circuit 2
Since the voltage input to 71 to 278 and the voltage output from each DC-DC converter circuit 271 to 278 are low,
A large withstand voltage is not required for the circuit components constituting the DC-DC converter circuits 271 to 278, and the capacity can be reduced. Therefore, each DC-DC converter circuit 27
Small and light-weight circuit components can be used as the circuit components 1 to 278. That is, as shown in FIG. 2B, the height of the entire chassis can be reduced, and a thin, compact and lightweight power conversion device can be configured.

Further, since small and light-weight circuit components can be used, the degree of freedom in component arrangement is increased, and therefore components that should be adjacent to each other can be disposed adjacent to each other, so that the wiring distance can be shortened sufficiently. Moreover, since the primary side and the secondary side are separately mounted via the transformer 34, there is no fear that wirings will be mixed on the primary side and the secondary side. Therefore, sufficient countermeasures against signal noise and radio wave noise can be taken.

Each DC-DC converter circuit 271 ...
Since 278 has the same configuration and is regularly arranged and mounted on the chassis substrate, the mounting work of the circuit components on the substrate can be easily automated and mass production can be easily realized.

In the above embodiment, the input terminals and output terminals of the DC-DC converter circuits 271 to 278 are connected in series, but the present invention is not limited to this, and the input terminals and the output terminals are not limited thereto. May be connected in parallel or in a combination of series and parallel.

[0021]

As described above in detail, according to the present invention, it is possible to reduce the size of each component to be used, and to regularly and separately mount the primary side and the secondary side on the wiring board. It is possible to provide a power conversion device that can be downsized, can sufficiently take measures against signal noise and radio wave noise, and can be easily mass-produced.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of mounting circuit components in the embodiment.

FIG. 3 is a diagram showing a conventional circuit component mounting example.

[Explanation of symbols]

271-278 ... DC-DC converter, 31 ... Smoothing capacitor, 34 ... Transformer, 35 ... Field effect transistor.

Claims (1)

[Claims] 1. A plurality of DC-DC converters having the same or substantially the same circuit configuration on a wiring board, the primary side and the secondary side are separated and regularly arranged and mounted, and each of the DC-DC converters is mounted. An electric power converter comprising a single DC-DC converter configured by connecting the input terminal and the output terminal of the above in series or in parallel or in combination of series and parallel.