JP2005183489A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device where a choke input type rectification smoothing circuit can be adopted for a pulley main amplifier whose mounting density of a component is high and a small audio amplifier, by arranging a choke inductor used in the choke input type rectification smoothing circuit in a central air gap of a toroidal type power transformer. <P>SOLUTION: The toroidal type power transformer 2 is used for a voltage reducing means of a power supply circuit, and the choke inductor 3 is arranged in a part of a smoothing means. The choke inductor 3 is disposed in the central air gap of the toroidal type power transformer 2. They are resin-sealed in a metal shielding case 4 so as to be integrated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

As a power supply circuit for an audio amplifier, particularly for a choke input type rectifying and smoothing circuit intended to eliminate harmonic noise components, a power supply device that does not require a space for installing a choke inductor and suppresses the cost of the choke inductor .

The function of the audio amplifier is to faithfully amplify a minute voltage music signal. In particular, audio amplifiers that pursue high sound quality are required to remove harmonic noise components that affect signal processing for supplied power.

For this reason, a choke input type rectifying / smoothing circuit is employed in some audio amplifiers pursuing high sound quality.
The choke input type rectifying and smoothing circuit steps down an AC commercial power supply to an arbitrary AC voltage with a power transformer, then rectifies the power supply voltage from AC to pulsating current with a rectifier diode, and smoothes the pulsating current with a smoothing capacitor via a choke inductor. And converted to direct current.

Examples of audio amplifiers that employ a choke input type rectifying and smoothing circuit include an audio amplifier manufactured by Nippon Marantz Co., Ltd., a control amplifier “SC-7S1”, a power amplifier “MA-9S1”, and the like.

Choke input type rectifying / smoothing equipment: Audio control amplifier “SC-7S1” and audio power amplifier “MA-9S1” manufactured by Nippon Marantz Co., Ltd.

In the audio control amplifier “SC-7S1” and audio power amplifier “MA-9S1” manufactured by Nippon Marantz Co., Ltd., the choke inductor used in the choke input type rectifying and smoothing circuit was a large and expensive component. .

When the choke inductor is energized, a leakage flux (leakage magnetic flux) is generated, which may affect adjacent electric circuits. In addition, the choke inductor core may vibrate due to energization. In order to solve these two problems, it was necessary to take measures such as enclosing the choke inductor with a metal shield case to prevent leakage flux and encapsulating with resin to suppress vibration. As a result, the choke inductor is expensive.

In addition, the choke inductor surrounded by the metal shield case has a large shape and requires a large space for arrangement as compared with other power supply circuits. Larger power supply circuits lead to larger audio amplifiers, which is not suitable for efforts to reduce the size of light and thin in the Japanese living environment.

FIG. 1 is a perspective view including a partial cutout showing a power supply device 1 of the present invention.
FIG. 2 is an exploded view showing a structure in which the choke inductor 3 according to the present invention is arranged in the central gap of the toroidal power transformer 2 and integrated in the metal shield case 4.

The present invention is provided with a toroidal power transformer 2 having a donut shape and a choke inductor 3 for smoothing the output from the toroidal power transformer 2, and the choke inductor is provided in the central gap of the toroidal power transformer. It is characterized by being disposed and integrated with resin in the metal shield case 4 together.

The smoothing member disposed in the central gap of the toroidal power transformer is not limited to the choke inductor, and a resistor or a capacitor may be used.

  By disposing the choke inductor used in the choke input type rectifying and smoothing circuit in the central gap of the toroidal type power transformer, a space for installing the choke inductor is not required. For this reason, the choke input type rectifying / smoothing circuit can be adopted for a pre-main amplifier or a small audio amplifier having a relatively high mounting density of components.

Also, since the metal shielding case for the choke inductor is also used as the metal shielding case for the toroidal power transformer, the resin sealing work can be done only once, so the metal shielding case for the choke inductor and the accompanying resin sealing work are not required. The cost can be reduced accordingly.

The invention can be implemented as follows for a choke input current smoothing circuit using a toroidal power transformer having a donut shape as a power transformer and using a choke inductor.

The core size of the toroidal power transformer is determined by the rated output power specifications of the audio amplifier.

The core size of the choke inductor is determined by the voltage / current specification of the power supply circuit. As for the core size, it is desirable to be as small as possible in order to be disposed in the central gap of the toroidal power transformer. For this reason, an EI core that is formed by stacking silicon steel plates having E and I shapes, which can be formed with a large number of turns and whose overall shape is close to a cube, is optimal.

If the determined outer shape of the choke inductor is smaller than the central gap portion of the toroidal power transformer, the invention can be implemented.
When it becomes larger than the central gap of the toroidal power transformer, the core size of the choke inductor is reduced by taking measures to reduce power consumption with respect to the voltage / current specifications of the power circuit.

If the choke inductor cannot be reduced in size, the choke inductor is arranged in the central gap of the toroidal power transformer by adjusting the core size of the toroidal power transformer by one rank.

The toroidal power transformer in which the choke inductor is disposed in the central gap is housed in a metal shield case with each lead wire pulled out, and encapsulated with resin in the metal shield case.
Thus, the choke inductor for the choke input type rectifying and smoothing circuit has a structure integrated with the toroidal type power transformer.

The smoothing member disposed in the central gap of the toroidal power transformer is not limited to the choke inductor, and a resistor or a capacitor may be used.

The perspective view containing the notch which shows the power supply device of this invention. The exploded view which shows the structure which has arrange | positioned the choke inductor of this invention in the center space | gap part of a toroidal type power transformer.

Explanation of symbols

1: Power supply device 2: Toroidal power transformer 3: Choke inductor 4: Metal shield case 5: Chassis

Claims (1)

A toroidal power transformer having a donut shape and a choke inductor for smoothing the output from the toroidal power transformer are provided, and the choke inductor is disposed in the central air gap of the toroidal power transformer to provide a metal shield. A power supply device that is sealed with resin in a case.

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