JP2002343073A - Av device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AV device which can evade such a problem that a noise signal is overlapped on a video/voice output signal as operation of a power source circuit, by arranging the power source circuit and an external input/output terminal at positions at which distance between them is farthest in a case. SOLUTION: In the AV device, a switching power source circuit 6 receiving supply of AC voltage and outputting desired voltage to a load circuit side and a video/voice signal processing circuit 8 are provided on one wiring substrate 3 stored in a case 2, the switching power source circuit 6 is arranged near a rear side wall 2b of the case 2, and the external input terminal and external output terminals 10-13 are arranged at a left or right side wall 2c of the case 2 positioned on a diagonal for the switching power source circuit 6 in the case 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AV device such as a DVD player or a VCR, and more particularly, to a problem that a video / audio output signal is affected by noise when a power supply unit having a switching power supply circuit operates. The present invention relates to an AV device capable of preventing the problem.

[0002]

2. Description of the Related Art As an example of a switching power supply widely used in a power supply section of an AV apparatus, a power supply in which an input terminal and an output terminal are provided on a printed circuit board and housed in a case body is known. (See Japanese Utility Model Laid-Open No. 5-76088). In this device, an input terminal and an output terminal are separately provided and juxtaposed on the bottom surface of a case body, and the input terminal and the output terminal are arranged diagonally with respect to the case body. This solves the conventional problem that, when a plurality of switching power supply devices are provided side by side on a printed circuit board, it is necessary to divide the input side patterns into two layers by interposing an insulating material so that the input side patterns do not intersect and contact with each other. That is, the manufacturing process of the printed circuit board can be simplified.

In this type of power supply device, a switching power supply circuit, an audio signal processing circuit, and the like are provided on a single printed circuit board. External input / output terminals connected to the audio signal processing circuit are provided. Since the external input / output terminal is not separated from the switching power supply circuit, there is a problem that the external input / output terminal receives high-frequency induction and transmits a noise signal to the externally connected device. As an example of this, in the case of a popular DVD player, as shown in FIG.
2, a printed circuit board 23 having a substantially square shape and the same size is housed, and a power supply unit 26, a video / audio signal processing unit 28 and the like are provided on the printed circuit board 23. The case body 22
The power cord 4 is pulled out from the right side of the rear wall 22b, and a plurality of jacks and connection terminals 10 to 13 for connecting to an external device are exposed near the left side.

The printed circuit board 23 is provided with holes 23e and 23f for arranging the components of the mechanical mechanism at various places. Then, the right portion 2 of the printed circuit board 23
The circuit element of the power supply unit 26 is mounted on the 3c side, and the circuit element of the video / audio signal processing unit 28 is mounted on the rear end 23b side. Further, circuit elements constituting the built-in circuit unit 27 including the display circuit 27a and the operation signal processing unit 27b are mounted on the front end 23a side. In the power supply section 26, the other end of the power cord 4 having the plug 5 attached to one end is connected to an input terminal provided on the right edge 23h side. This input terminal is connected to a switching circuit 2 including a plurality of switching transistors via a bridge circuit 26a.
6b is connected. 26c is the switching circuit 2
The transformer connected to 6b, 26d is a transformer 26c
A rectifier circuit for converting the output of the rectifier circuit into a direct current, a voltage stabilizing circuit for stabilizing the output of the rectifier circuit 26d;
Is a voltage output circuit that supplies the output of the voltage stabilizing circuit 26e to each load circuit.

The output side of the voltage output circuit 26f is connected to a built-in circuit section 27 and a video / audio signal processing section 28, and also to a mechanical mechanism section and an optical pickup side circuit via a detachable terminal section 26h. ing. The video / audio signal processing unit 28 includes a DVD signal processing unit, an A / V decoder, a video encoder, a D / A converter, and the like.
The input side is connected to the optical pickup side circuit via the detachable terminal section 28a. On the other hand, the output side is connected to two sets of RCA jacks 10, one S-video output terminal 11, one optical signal output terminal 12, and two sets of audio jacks 13, respectively. These jacks and output terminals 10
13 are arranged side by side substantially at the center on the rear side wall 22c of the case body 22.

In this VD player, when the insertion plug 5 is plugged into an outlet, an AC voltage from a commercial power supply is guided to the power supply section 26, and the switching circuit 26b starts switching operation, thereby causing the voltage output circuit 26f to operate.
Supplies a DC voltage to each part of the circuit on the load side. With this voltage supply, the DVD playback system starts operating, and after the recorded information of the DVD is read and processed by the video / audio signal processing unit 8, the video signal and the audio signal are converted to the jack and output terminal 10 by the video signal and the audio signal. 13 to the external device side.

[0007]

However, in the above-mentioned conventional AV apparatus and DVD player, the switching power supply circuit and the video / audio signal processing circuit arranged side by side on the printed circuit board are adjacent to each other, and the video signal output terminal and the audio signal Since the output terminal is also close to the switching power supply circuit, there is a problem that externally connected devices are affected by noise. That is, in a DVD player or the like, when the switching circuit 26b of the power supply unit 26 starts a switching operation, a high frequency which is a factor of noise is generated. The higher the frequency, the greater the induction nearer to the switching circuit 26b, which is the oscillation source.
13 are also strongly affected by high frequencies. Then, the noise signal caused by the high frequency is superimposed on the video signal and the audio signal transmitted from the DVD player to the external device, and the noise is emitted from the speed of the external device. In addition, the video signal is also affected by noise, causing a problem that the display image on the monitor is disturbed or darkened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is provided with the operation of the power supply circuit by arranging the power supply circuit and the external input / output terminal at the most distant position in the housing. It is an object of the present invention to provide an AV apparatus that can avoid a problem that a noise signal is superimposed on a video / audio output signal.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, an AC voltage is supplied onto a single wiring board housed in a housing. A switching power supply circuit for outputting a required voltage on the load circuit side, and a video / audio signal processing circuit for processing video and audio signals are provided, and a power cord connected to an input side of the switching power supply circuit is provided in the housing. In the AV apparatus, the external input terminal connected to the input side of the video / audio signal processing circuit and the external output terminal connected to the output side are pulled out from the side wall of the body and attached to the side wall of the housing. The switching power supply circuit is arranged near the rear side wall of the housing, and the external input terminal and the external output terminal are arranged diagonally with respect to the switching power supply circuit in the housing. Or it is characterized in that arranged on the right wall.

According to a second aspect of the present invention, there is provided a power supply circuit for receiving a supply of an AC voltage and outputting a required voltage to a load circuit side on a single wiring board housed in a housing; A video / audio signal processing circuit for processing a signal and an audio signal, wherein a power cord connected to an input side of the power supply circuit is drawn out from a side wall of the housing, and the video / audio signal processing circuit is provided. In an AV apparatus in which an external input terminal connected to the input side of the AV device and an external output terminal connected to the output side are mounted on the side wall of the housing, the power supply circuit, the external input terminal and the external output terminal, It is characterized in that it is arranged at a position where the mutual space is most separated in the housing. The invention according to claim 3 is the switching power supply circuit, wherein the power supply circuit includes a switching element, wherein the switching element is disposed near a rear wall of the housing, and the external input terminal and the external output terminal are provided. However, the switching element is characterized in that the switching element is disposed on a left or right side wall of the housing which is arranged diagonally in the housing. Further, the invention according to claim 4 is characterized in that the wiring board is formed to have substantially the same size as the housing.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a case main body showing an external connection terminal of the AV device according to the embodiment of the present invention, and FIG. 2 is a schematic layout diagram showing respective circuit parts mounted on a wiring board of the AV device. This AV device is applied to a DVD player 1 that reproduces recorded information of a DVD, and accommodates a mechanical mechanism of a reproducing system in a case main body 2 of the DVD player 1 and one piece for mounting various circuit elements. Printed circuit board 3 is built in.

The case main body 2 is formed in a substantially rectangular shape as shown in FIG. 1, and is provided with a disc tray insertion / removal opening, an LCD display section, a key operation section and the like on the front side wall 2a (see FIG. 2). A through hole 2e for drawing out the power cord 4 is formed in the rear side wall 2b of the case body 2, and a plurality of jacks for connecting to external devices and small holes for exposing the connection terminals 10 to 13 are formed in the right side wall 2c. Has been established. In the case body 2, although not shown, a mechanical mechanism including a motor for rotating the DVD, an optical pickup for reading recorded information of the DVD, a servo circuit for controlling the drive of the optical pickup and the motor, and the like. Is stored.

As shown in FIG. 2, the printed circuit board 3 is formed in a substantially rectangular shape smaller in size than the case main body 2, and has holes 3e for disposing components of the mechanical mechanism in various places. , 3f has been established. Then, almost the entire electric circuit is mounted on the single printed circuit board 3. That is, while the circuit element of the power supply unit 6 is mounted on the rear end 3b side of the printed circuit board 3, the video / audio signal processing unit 8 and other circuit elements constituting the built-in circuit unit 7 are mounted on the front end 3a side, On the lower surface side, a wiring pattern for connecting these circuit elements is formed. Power supply unit 6
Is a conventionally known switching power supply circuit in which the other end of the power supply cord 4 having the plug 5 attached to one end is connected to the input terminal 4a. The input terminal 4a is provided on the left edge 3g side of the rear end 3b of the printed circuit board 3, and is connected to a bridge circuit 6a via a fuse and a line filter.

A switching circuit 6b comprising a plurality of switching transistors and the like is connected to the bridge circuit 6a. This switching circuit 6b is also arranged near the left edge 3g of the printed circuit board 3, and the primary side of the transformer 6c is connected to the output side. A rectifier circuit 6d composed of a plurality of diodes is connected to the secondary side of the transformer 6c. Further, an output side of the rectifier circuit 6d is connected to an error detection circuit (not shown) and a voltage stabilizing circuit 6e including a photocoupler 6g and the like.
The output side of the voltage stabilizing circuit 6e has a voltage of 3.3V.
And a voltage output circuit 6f that outputs voltages having different levels such as 5.0V and 5.0V.

The voltage output circuit 6f has a plurality of output terminals, and is connected to connection terminals of the mechanical mechanism via detachable terminals 6h provided on the left side 3d of the printed circuit board 3. . Further, a video / audio signal processing unit 8 and a built-in circuit unit 7 arranged on the front end 3a side of the printed circuit board 3 are connected to each output terminal of the voltage output circuit 6f. The built-in circuit section 7 includes a display circuit 7a, an operation signal processing circuit 7b, and the like. The display circuit 7a is connected to an LCD display unit attached to the front wall 2a. The operation signal processing circuit 7b is connected to a key operation unit and a remote control reception unit disposed on the front side wall 2a.

The video / audio signal processing section 8 includes a DVD signal processing section, an A / V decoder, an optical signal output circuit, and an SVHS.
It is provided with an output circuit and the like. The video / audio signal processing section 8 has an input side connected to the optical pickup side circuit via a detachable terminal section 8a, and an output side connected to an RCA jack 10, an S video output terminal 11, an optical signal output terminal 12, and an audio jack 13. Each is connected. As shown in FIG. 1, the RCA jack 10 has L channel and R channel audio signal output terminals 10a and 10a.
b and a video signal output terminal 10c, and two sets of RCA jacks 10 having these three terminals 10a, 10b, and 10c arranged side by side are arranged vertically.

The S-video output terminal 11 has four pins, two for a luminance signal and two for a chroma signal, fixed in a cylindrical insertion portion, and has a S-video input terminal.
The connector attached to the V to S cable is connected.
The optical signal output terminal 12 has an optical signal transmission element provided in the insertion portion, and is connected to a connector attached to an optical signal transmission cable from a digital audio device. The audio jacks 13 are L-channel and R-channel audio signal output terminals 13a and 13b, and two sets of audio jacks 13 having these two terminals arranged side by side are arranged vertically. These jacks and output terminals 10 to 13
On the right side wall 2c of the case body 2, an RCA jack 10, an S-video output terminal 11, an optical signal output terminal 12, and an audio jack 13 are arranged in this order from the front side wall 2a side to the rear side wall 2b side.

Although not shown, the DVD player 1 outputs a signal read from a DVD track by the optical pickup to an RF amplifier. This RF amplifier amplifies the read signal and outputs it to the DVD equalizer.
This DVD equalizer uses the RF signal from the RF amplifier to
The D band RF signal is filtered and equalized and sent to the DVD signal processing unit. The DVD signal processor receives the data stream in the DVD band output from the DVD equalizer, demodulates the modulated data, corrects an error generated in this process, and outputs the result to the A / V decoder. This A / V
The decoder separates a video signal and an audio signal from data output from the DVD signal processing unit, and outputs the processed video signal to a video encoder and the audio signal to a D / A converter.

A converter for converting an audio signal into an optical signal is connected to the A / V decoder. And
The optical signal output terminal is connected to the output side of the converter, and the audio signal separated by the A / V decoder is transmitted to the optical signal output terminal side as an optical signal. The video encoder encodes a video signal from the A / V decoder into a corresponding video display system, and encodes the video signal into a video signal output terminal 10c of each of the RCA jacks 10 and a video signal pin of the S video output terminal 11. To send to. On the other hand, the D / A converter converts a digital audio signal into an analog signal and converts the L and R signal output terminals 10a and 10b of the
The signals are sent to the audio signal pin of the video output terminal 11 and the L and R signal output terminals 13a and 13b of the audio jack 13, respectively.

Next, the operation of the DVD player will be described with reference to FIGS. The user has D
When the VD player 1 is used, when the insertion plug 5 is inserted and connected to an outlet, an AC voltage from a commercial power supply is guided to the power supply unit 6. The power supply unit 6 includes a bridge circuit 6
When the DC voltage output from a is applied to the switching circuit 6b, this circuit element starts the switching operation, and the AC voltage is supplied to the transformer 6c. After the AC output of the transformer 6c is converted into a DC voltage by the rectifier circuit 6d and stabilized by the voltage stabilizing circuit 6e,
The voltage is supplied from the voltage output circuit 6f to each circuit on the load side.
With this voltage supply, the DVD playback system starts operating, and D
The VD recorded information is read and sent from the optical pickup side circuit to the video / audio signal processing unit 8. The video / audio signal processing unit 8 processes the transmission signal,
The video signal and the audio signal are connected to the jacks and the output terminals 10 to 10.
Send to 13 side. Therefore, output signals are respectively transmitted to the external devices via the cables connected thereto.

Incidentally, in the DVD player 1, since the power supply section 6 is constituted by a switching power supply circuit, when the switching circuit 6b of the power supply section 6 starts the switching operation, the switching circuit 6b side usually operates at 50 kHz. A high frequency of about 100 KHz is generated. Although this high frequency is a factor of noise, the problem affecting the external device connected to the DVD player 1 is greatly suppressed. That is, in the DVD player 1, the circuit element of the power supply unit 6 and the circuit element of the video / audio signal processing unit 8 are mounted on one printed circuit board 3 housed in the case body 2 with a space therebetween. . In particular, the switching circuit 6b is disposed near the left edge 3g on the rear end portion 3b side of the printed circuit board 3, and the RCA jack and the output terminal 1
Reference numerals 0 to 13 and the like are arranged concentratedly near the right edge 3 h on the front end 3 a side of the printed circuit board 3.

Therefore, the switching circuit 6b and the RCA jacks and the output terminals 10 to 13 are arranged diagonally on the printed circuit board 3 and are most distant from each other.
For this reason, induction of the high frequency generated on the switching circuit 6b side to the RCA jack and the output terminals 10 to 13 is greatly reduced. This makes it difficult for a noise signal due to a high frequency to be superimposed on a video signal and an audio signal transmitted from the DVD player 1 to the external device, so that noise is not emitted from the speed of the external device. In addition, since the video signal is hardly affected by the noise, the problem that the display image on the monitor is disturbed or darkened does not occur.

In the above embodiment, one printed circuit board 3 accommodated in the substantially rectangular case body 2 is used.
Has been described as an example in which the case body and the printed circuit board are formed to be substantially the same size, and the operation and effect are comparable to those of the above embodiment. can get. Also, in such an example,
A power supply unit 6 including a switching circuit 6b is disposed near the right edge on the rear end 3b side of the printed circuit board 3,
The A jack, the output terminals 10 to 13 and the like may be arranged near the left edge on the front end 3a side of the printed circuit board 3.

[0024]

As described above, according to the first aspect of the present invention, the switching power supply circuit and the external input terminal and the external output terminal of the video / audio signal processing circuit are arranged diagonally in the housing. Since these terminals are located farthest away from the switching power supply circuit, each terminal is less susceptible to induction of high frequency generated at the time of switching operation of the switching power supply circuit. While noise is no longer introduced into the video / audio signal processing circuit, noise is no longer transmitted to the externally connected device via the external output terminal, and noise is emitted from speakers of the externally connected device or displayed on the monitor. This has the effect of avoiding problems such as disturbances. Further, since the power supply circuit and the external input terminal and the external output terminal are disposed at the positions where the power supply circuit and the external output terminal are most separated from each other in the housing, a circuit element that generates a high frequency is used in the power supply circuit. In this case, it becomes difficult for each terminal to receive high-frequency induction generated during the operation of the power supply circuit, and noise is not introduced into the video / audio signal processing circuit via the external input terminal, while external noise is prevented via the external output terminal. Noise is no longer transmitted to the connected device, and there is an effect of avoiding a problem that noise is emitted from a speaker of the externally connected device or an image displayed on a monitor is disturbed.

According to a third aspect of the present invention, the power supply circuit is a switching power supply circuit having a switching element, wherein the switching element is disposed near a rear side wall of the housing, and an external input terminal and an external output terminal are provided. Since the switching element is disposed on the left or right side wall of the housing which is arranged diagonally in the housing, each terminal is hardly subjected to induction of high frequency generated at the time of switching operation of the switching power supply circuit, and external input is performed. While no noise is introduced into the video / audio signal processing circuit through the terminal, the noise is not transmitted to the externally connected device through the external output terminal. There is an advantage that problems such as disturbed displayed images are avoided. According to a fourth aspect of the present invention, since the wiring board is formed to have substantially the same size as the housing, the distance between the switching power supply circuit, the external input terminal, and the external output terminal in the housing is the largest. Thus, there is an advantage that each terminal is less likely to receive high-frequency induction generated during the switching operation of the switching power supply circuit.

[Brief description of the drawings]

FIG. 1 is a perspective view of a case main body showing an external connection terminal of an AV device according to an embodiment of the present invention.

FIG. 2 is a schematic layout diagram showing circuit components mounted on a wiring board of the AV device.

FIG. 3 is a schematic layout diagram showing circuit components mounted on a wiring board of a conventional AV device.

[Explanation of symbols]

 Reference Signs List 2 housing 2b rear wall 2c right side wall (right side wall) 3 wiring board 6 power supply section (switching power supply circuit) 8 video / audio signal processing circuit 10-13 video / audio signal output terminal

Claims (4)

[Claims] 1. A switching power supply circuit for receiving a supply of an AC voltage and outputting a required voltage to a load circuit on a single wiring board housed in a housing, and a video for processing a video signal and an audio signal. A voice signal processing circuit is provided,
A power cord connected to the input side of the switching power supply circuit was pulled out from the side wall of the housing, and connected to an external input terminal and an output side connected to the input side of the video / audio signal processing circuit. In an AV device having an external output terminal attached to a side wall of the housing, the switching power supply circuit is disposed near a rear wall of the housing, and the external input terminal and the external output terminal are connected to the switching power supply circuit in the housing. An AV apparatus, wherein the AV apparatus is disposed on a left or right wall of a housing which is arranged diagonally in the body. 2. A power supply circuit for receiving a supply of an AC voltage and outputting a required voltage to a load circuit side, and a video / audio signal for processing a video signal and an audio signal, on a single wiring board housed in a housing. An audio signal processing circuit is provided, and a power cord connected to an input side of the power supply circuit is drawn out from a side wall of the housing, and an external input connected to an input side of the video / audio signal processing circuit. In an AV device in which a terminal and an external output terminal connected to an output side are mounted on a side wall of the housing, the power supply circuit and the external input terminal and the external output terminal are most separated from each other in the housing. An AV apparatus, wherein the AV apparatus is disposed at a position. 3. The power supply circuit according to claim 1, wherein the power supply circuit is a switching power supply circuit including a switching element, wherein the switching element is disposed near a rear wall of the housing, and the external input terminal and the external output terminal are different from the switching element. The AV device according to claim 2, wherein the AV device is disposed on a left or right side wall of the case that is arranged diagonally in the case.
apparatus. 4. The wiring board according to claim 2, wherein the wiring board is formed to have substantially the same size as the housing.
2. The AV device according to item 1.