Electronic equipment a terminal for inputting or outputting signals to be used in a circuit provided in electronic equipment, and a fuse provided on a signal ground line between the terminal and the circuit.
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1. Electronic equipment comprising:
a terminal for inputting or outputting signals to be used in a circuit provided therein, said terminal being connected to said circuit through at least a signal line and a signal ground line; a fuse provided on said signal ground line, wherein said signal ground line is contained in a signal ground pattern; and a solder land provided on said signal ground pattern.
4. Electronic equipment comprising:
a pre-amplifier; a terminal on said pre-amplifier for inputting or outputting signals; a signal ground pattern, wherein said signal ground pattern is provided in the vicinity of said terminal; and a first fuse, wherein said first fuse is provided in the vicinity of said terminal and is connected to another piece of electronic equipment, and wherein said first fuse is designed to blow when electric current equal to or greater than a predetermined value flows through said signal ground pattern.
12. Electronic equipment comprising:
a terminal for inputting or outputting signals to be used in a circuit provided therein, said terminal being connected to said circuit through at least a signal line and a signal ground line; and a first fuse provided on said signal ground line, wherein said signal ground line is contained in a signal ground pattern, wherein said first fuse is connected to another piece of electronic equipment, and wherein said first fuse is designed to blow when electric current equal to or greater than a predetermined value flows through said signal ground pattern.
3. Electronic equipment according to
5. Electronic equipment according to
6. Electronic equipment according to
7. Electronic equipment according to
9. Electronic equipment according to
wherein said first fuse and said at least one solder land are formed on said signal ground line.
10. Electronic equipment according to
11. Electronic equipment according to
13. Electronic equipment according to
15. Electronic equipment according to
16. Electronic equipment according to
17. Electronic equipment according to
19. Electronic equipment according to
wherein said first fuse and said at least one solder land are formed on said signal ground line.
20. Electronic equipment according to
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1. Field of the Invention
The present invention generally relates to electronic equipment having an overcurrent protection fuse, and more particularly to electronic equipment having a fuse provided on a signal ground line.
2. Description of the Related Art
In recent years, users occasionally use car stereos by respectively connecting external power amplifiers thereto so as to enjoy audio from the car stereos with higher quality at a larger volume. In this case, audio signals are amplified by an amplifier circuit provided in the power amplifier. Then, sounds represented by the amplified signals are outputted from speakers. That is, as shown in
Meanwhile, when a user uses both of a car stereo and a power amplifier in a car, it is necessary to connect the power line (corresponding to the positive terminal (+)) and the ground line (corresponding to the negative terminal (-)) of a battery to each of the car stereo and the power amplifier. However, because it is usual that an operation of connecting this battery thereto is performed by using power cables 6, there is a fear that miswiring may occur.
Usually, the car stereo and the power amplifier are constructed in such a way as not to operate even when miswiring occurs in the power cables 6. However, the car stereo and the power amplifier may operate when power or a ground is supplied thereto from a path other than the power cables 6. Hereinafter, a representative example of this is described with reference to FIG. 4.
However, in this case, electric current I2 consumed by the power amplifier 3 cannot return directly to the battery through the power cable 6, as illustrated n FIG. 3. Thus, the current I2 returns to the battery 5 through the RCA cable 2 and the car stereo 1, as illustrated in FIG. 4. Therefore, in addition to the current I1 consumed by the car stereo 1, the electric current I2 additionally flows through the car stereo 1.
Because the current I1 is a known current for the car stereo 1, a sufficient current capacity is ensured at a design stage. On the other hand, the current I2 is an unknown current, which is caused by miswiring, for the car stereo 1. Moreover, the current I2 flows through a signal ground pattern constituted by a relatively thin pattern. Thus, a sufficient current capacity is not ensured for the current I2. Therefore, in the car stereo 1, a thin part of the signal ground pattern provided therein, that is, a part having a small current capacity is burnt out owing to the current I2. This causes a fault of the stereo. Especially, when all currents to be passed through electronic equipment, such as the power amplifier 3, which consumes large current, flow thereinto, this inflow causes the breakage of electronic components in addition to the burning-out of the signal ground pattern.
A non-limiting aspect of the present invention is to solve the aforementioned problem.
To achieve the above mentioned aspect, there is provided electronic equipment that comprises a terminal for inputting or outputting signals to be used in a circuit provided therein. This terminal is connected to the circuit through at least a signal line and a signal ground line. The electronic equipment further comprises a fuse provided on the signal ground line.
Hereinafter, an embodiment of the invention is described with reference to FIG. 1.
As shown in
Thus, in this car stereo, even when a miswired power amplifier is connected thereto, electric current consumed by the power amplifier inevitably flows through the pattern fuse 11 provided in the vicinity of the pre-amplifier output terminal. When overcurrent, the amount of which is equal to or more than that of consumption current in the case of ordinary use, flows therethrough, the pattern is melted by heat. Consequently, at each generation of overcurrent, the pattern fuse 11 is inevitably melted. Hence, this car stereo can prevent electric current consumed by the power amplifier 3 from flowing thereinto. Thus, important patterns and electronic components provided therein can be protected. Incidentally, similar effects can be obtained by using a retrofit fuse, such as a chip fuse, instead of the pattern fuse.
Further, this car stereo has a pattern fuse formed in the vicinity of a terminal so as to be connected to another piece of electronic equipment. Thus, a failure component can easily be located. Moreover, the cause of the failure can be identified to a certain extent. That is, when the fuse pattern is melted in spite of the fact that no failures occur in this car stereo itself, there is a good possibility that over current is generated because the ground line is not connected to one of the car stereo and the power amplifier. Therefore, in such a case, the recurrence of the failure can be prevented by urging a user to recheck whether the power cables are connected to each of the car stereo and the power amplifier.
Furthermore, this car stereo has solder lands 12, between which a retrofit chip fuse is attached in the proximity of the fuse pattern 11. Thus, this car stereo can easily be repaired. Moreover, this product uses the chip fuse only when the pattern fuse is melted. Consequently, the cost of components of the product can be held down.
Incidentally, although the car stereo has been described byway of example in the foregoing description of this embodiment, the scope of application of the invention is not limited thereto. It is sufficient that the electronic equipment of the invention has a terminal to be connected to another piece of electronic equipment, and that the electronic equipment needs to be connected to a ground line serving as a power cable from the power supply.
As described above, according to the electronic equipment of the invention, a fuse is inserted on the signal ground line to be connected to an input/output terminal that is connected to another piece of electronic equipment. Consequently, an overcurrent, which is generated owing to miswiring from a power supply, can be restrained from passing through a signal ground line and affecting another piece of electronic equipment.
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| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Apr 12 2002 | SUENAGA, SHOJI | Pioneer Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012976 | /0679 | |
| Jun 06 2002 | Pioneer Corporation | (assignment on the face of the patent) | / |
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