JP2001005577A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make preventable a receiving part or a transmitting part from being electrically destroyed at the time of insertion of a plug, and to make preventable the malfunction of a communicating circuit due to any contract with the other terminal during insertion of the plug. SOLUTION: In this electronic equipment, after a circuit 4 waiting for a prescribed time is operated according to a signal 5 for detecting that an electric plug 2 is completely inserted into a receptacle 1, a switch 3 is short-circuited so that the electric plug 2 can be simultaneously connected with each signal line of a communicating circuit 10. Thus, during the insertion of the plug, the switch 3 is opened so that each signal line between the receptacle and the communicating circuit part can be electrically opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device using a detachable communication cable.

[0002]

2. Description of the Related Art Generally, when electronic devices in operation are connected by a communication cable, the ground (reference potential) of the other device is the same as the ground of the own device immediately before the connection. Since the potential is not guaranteed, if the signal electrodes contact each other before the ground electrodes of both devices are connected, the signal electrodes of both devices will come into contact with an excessive potential difference. In some cases, the receiving element or the transmitting element may be destroyed.

FIG. 4 shows the shapes of a plug 16 and a receptacle 17 standardized by IEEE1394. IEEE
The electrode of the E1394 standard receptacle is arranged up to a position where the power supply-related electrode 18 is close to the tip of the receptacle 17, and the signal electrode 19 is arranged at a position deeper than that. As a result, when the plug 16 and the receptacle 17 are connected, the power supply electrode comes in contact with the signal electrode before the signal electrode, and first, the ground (reference potential) between the devices and the power supply are connected first. After the preparation for connecting the signal lines is completed, the signal lines are safely connected. As a result, problems such as unexpected excessive voltage being applied to the receiving circuit and the transmitting circuit, and inconsistent data being input to the IEEE 1394 state transition circuit to cause malfunctions are solved.

[0004] In general, when electronic devices in operation are connected with a communication cable, indefinite data is input as noise to the receiving side depending on the order in which a plurality of signal lines are connected. There was a problem of malfunction.

As a means for solving this problem, Japanese Patent Laid-Open Publication No. 2-53125 discloses a device for preventing a malfunction when connecting the plug and the receptacle. On the other hand, separate electrodes for connection detection are provided at both ends of the plug and the receptacle where the electrodes are lined up in the vertical direction.If the voltage status of the electrodes at both ends does not match, it is determined that the connection is in progress and the operation of the electronic device is performed. This is to interrupt and prevent malfunction.

[0006]

A small single-headed plug (hereinafter referred to as a mini-plug) is applied as an electrical plug such as IEEE1394, and an OMJ (optical mini-jack shared with photoelectric) is applied as a corresponding receptacle. As a result, development for reducing the area occupied by the receptacle of the device is also in progress.

[0007] The OMJ is provided with terminals for electrical mini-plugs, and a light-receiving circuit for processing an optical signal and a light-emitting circuit when an optical fiber plug having the same shape as the mini-plug is inserted. A circuit (hereinafter referred to as an optical front-end circuit) is built in, and one receptacle can support both an optical plug and an electric plug. As a result, it is not necessary to use two receptacles for an optical signal and an electrical signal, so that the size of the device can be reduced. In addition, studies are underway to transfer IEEE 1394 signals using a single optical fiber on the premise that the present invention is applied to a small receptacle such as the OMJ.

In the case of such an electric mini plug (small single-head plug), the electrodes are arranged in a direction parallel to the insertion direction as shown in the lower diagram of FIG. Since the conventional technology shown in FIG. 4 cannot be applied and the signal terminals may come into contact before the ground terminal is connected during insertion, the signal electrodes of both devices have an excessive potential difference. There is a problem in that the contact may occur while the transmitting and receiving elements having a low withstand voltage are used.

[0009] As another problem, an electrical mini-plug and a receptacle such as an OMJ which fits into the electrical mini-plug are IEEE-compatible.
When applied to a communication standard such as 1394, when inserting a mini-plug having the electrode arrangement as described above into a receptacle, it is necessary to wait until the plug is completely inserted and connected to the corresponding electrode of the receptacle. Each electrode of the plug will contact an electrode other than the corresponding electrode of the receptacle. The IEEE 1394 standard does not consider the case where the plug electrode contacts an electrode other than the corresponding electrode of the receptacle when inserting the plug. Therefore, when a mini-plug is used as the plug, when the plug is inserted, the plug is inserted. There is a problem that the communication circuit is adversely affected, for example, by contacting other electrodes in the device, undefined data is input and a malfunction occurs.

[0010] The plug and the receptacle having the shape disclosed in Japanese Patent Application Laid-Open No. 2-53125 solve the problem of general malfunction, but have a problem with a shape such as a mini-plug.

In the plug and receptacle defined by IEEE 1394, the positional relationship between the power supply terminal and the signal terminal is devised as shown in FIG. Occupies a large area with respect to the surface area of the device, and when optical fibers are used, there is no defined receptacle for sharing with an electric cable, and separate receptacles for electric signals and optical signals are provided. However, there is a problem that it is not suitable for small portable devices.

The present invention has been made to solve such a problem, and is disclosed in Japanese Patent Laid-Open No. 2-53125 and IE.
An object of the present invention is to solve the above-mentioned problem by using a mini-plug and a receptacle fitted therein, instead of a plug and a receptacle having a shape as seen in the EE1394 standard, and to provide a receptacle shared by photoelectric.

[0013]

An electronic device according to a first aspect of the present invention is an electronic device having a function of attaching and detaching a communication cable, wherein a plug of the communication cable is connected to a receptacle attached to the electronic device. A state in which the insertion is detected, comprising: means for detecting insertion; and opening / closing means for short-circuiting or opening a communication signal line between the receptacle and the communication circuit unit based on a detection result of the detection means. Then, the communication signal line between the receptacle and the communication circuit unit is short-circuited by the opening / closing means, and the communication signal line between the receptacle and the communication circuit unit is opened by the opening / closing means when insertion is not detected. Open to the public.

An electronic device according to a second aspect of the present invention is the electronic device according to the first aspect, further comprising a unit that waits for a specific period based on the detection of the insertion by the detection unit, The communication signal line between the receptacle and the communication circuit unit is short-circuited by the opening / closing means after the specific standby period.

An electronic device according to a third aspect of the present invention is the electronic device according to the first or second aspect, wherein the detecting means is performed by the receptacle.

An electronic apparatus according to a fourth aspect of the present invention is the electronic apparatus according to any one of the first to third aspects, wherein the plug and the receptacle correspond to a small single-head plug and a small single-head plug, respectively. It is characterized by being.

An electronic apparatus according to a fifth aspect of the present invention is the electronic apparatus according to the fourth aspect, wherein the receptacle is an optical mini jack (OMJ) that shares an optical signal and an electrical signal with plugs of the same shape. It is characterized by being.

The operation of the present invention will be described below.

According to the first aspect of the present invention, it is detected that the plug of the communication cable has been completely inserted into the receptacle of the electronic device, and the detection signal connects the signal line between the plug and the receptacle. Thus, the ground and the signal line are connected at the same time after they are completely inserted, and the signal line is not connected before the ground is connected, thereby solving the above problem.

Further, even if the electrodes come into contact with each other during insertion, they are not electrically connected, so that there is no adverse effect on communication circuits such as the IEEE 1394 standard, and the above problem is solved.

According to the second aspect of the present invention, after detecting that the plug has been inserted to the predetermined position, the plug is completely stopped in the receptacle by connecting the signal line after waiting for a specific time. By this time, bouncing due to rubbing the same electrode can be eliminated.

According to the third aspect of the present invention, a detection signal can be directly obtained from the receptacle by using the receptacle having the function of detecting the connection of the plug.
There is no need to provide a separate detecting means.

According to the fourth aspect of the present invention, IEEE1394
Compared with the case where a standard receptacle is used, the area occupied by the receptacle with respect to the surface area of the device can be reduced, which is effective in realizing miniaturization of the device.

According to the fifth aspect of the present invention, a single receptacle can handle an optical fiber plug, so that it is not necessary to mount separate receptacles for electric signals and optical signals, thereby realizing miniaturization of equipment. It is effective for

[0025]

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, a receptacle 1 is an optical mini jack (Optical Min. Jack) used in the present invention.
iJack; hereinafter, referred to as OMJ), and its outline is shown in FIG. 3 (b). The OMJ incorporates an optical front-end circuit 8 such as a light-receiving element corresponding to an optical fiber, a driving circuit thereof, a light-emitting element, and an amplifier circuit thereof in addition to the electrical contact section 7, as shown in FIG. The user can select and use either the electric cable plug or the optical fiber plug having the same shape. The OMJ in which only one of the light receiving unit and the light emitting unit is built in the receptacle is built in a portable MD recorder or the like, and has already been commercialized for digital audio communication. In the present embodiment, when an IEEE 1394 electrical signal is used, it is handled by a plug having a shape as shown in the lower diagram of FIG.

FIG. 2 shows the circuit of the electrical contact 7 of the OMJ. In FIG. 2, reference numeral 11 denotes a movable piece having an upper half made of an insulator and a lower half made of a conductive material, and 12 denotes a fixed fixed piece having a conductive property. When the plug is not inserted in the OMJ, as shown in FIG.
Are separated, and the output terminal 13 is pulled up to the power supply through the resistance inside the OMJ. Therefore, the same voltage as the power supply, that is, a high level is output from the output terminal 13. OM
When the plug is connected to J, the movable section 11 and the fixed section 12 are connected as shown in FIG. 3A, and the same voltage as the ground, that is, a low level is output from the output terminal 13.
Reference numeral 14 denotes a signal terminal corresponding to four types of signal lines in IEEE1394, and 15 denotes a power supply terminal including a ground. 14 and 15 are communication circuits 10 through the switch 3
Connected to.

In FIG. 1, reference numeral 5 denotes a detection signal for detecting that the plug is completely inserted into the receptacle, and is connected to the terminal 13 in FIG. Thus, signal 5 is low when the plug is fully inserted,
Otherwise, it is high.

Reference numeral 4 denotes a standby circuit, which waits for a specific time after the detection signal 5 changes from the high level to the low level, and then short-circuits the switch 3 by the control signal 6. While the detection signal 5 keeps the low level, the control signal 6 also keeps the switch 3 short-circuited, and the control signal 6 opens the switch 3 at the same time as the detection signal 5 becomes the high level. The standby circuit can be configured by using a digital timer or an element having an analog time constant. The waiting time is desirably 300 ms to 400 ms.

The switch 3 can be configured as a mechanical relay circuit or a circuit using an electric semiconductor.

Reference numeral 10 denotes an IEEE 1394 communication circuit or an LSI having the function thereof, which processes an IEEE 1394 electric signal when an electric plug is inserted, and converts an IEEE 1394 optical signal into one when an optical plug is inserted. Handles the protocol to be transmitted by the book optical fiber. The IEEE 1394 communication circuit 10 is connected to the OMJ 1 by an electric signal 9 and is connected via the switch 3 as shown in FIG. When an optical fiber is used, it communicates with the optical front end circuit 8 through an electric signal 9, and when an electric cable is used, it communicates with the contact 7 through the switch 3. Since the optical fiber plug does not have an electric terminal and does not have the above-mentioned problem, the description in the case of using the optical fiber plug is omitted.

When the electric plug is inserted into the OMJ 1, the movable section 11 and the fixed section 12 shown in FIG. 2 are separated while the plug is being inserted, and the detection signal 5 is at a high level. 1 when plug 2 is almost completely inserted
After the detection signal 5 becomes low level due to the contact between 1 and 12, the standby circuit 4 is activated and the switch 3
Are short-circuited, and the signal and power supply of the plug 2 are connected to the communication circuit 10 through the OMJ 1 and the switch 3.

From the start of the plug insertion to the end of the plug insertion, each electrode of the plug 2 comes into contact with an electrode other than the corresponding electrode of the OMJ 1, but since the switch 3 is open,
The signal of the plug 2 and the power supply are not connected to the communication circuit 10. When the plug 2 is inserted almost to the end and the sections 11 and 12 in FIG.
5 indicates that the respective electrodes on the OMJ side have reached the predetermined electrodes of the corresponding plugs 2, but for a short period of time until the plugs are completely inserted thereafter, the respective electrodes on the OMJ side correspond to the respective plugs. This causes the electrodes to rub against each other, resulting in an electrically unstable contact state (bouncing, chattering). However, since the switch 3 is still open by the standby circuit 4 during this unstable short period, the communication circuit 10 and the plug 2 are connected after the unstable period ends.

That is, when the plug and the OMJ are in contact with an electrode different from the predetermined electrode, or during the last unstable period of insertion, the signal of the plug 2 and the signal of the communication circuit 10 are not connected. Instead, all electrodes are simultaneously connected by the switch 3 after the insertion is completed and the signal is stabilized. For this reason, since the signal is not connected first without the ground being connected, there is no possibility that the transmitting element and the receiving element in the communication circuit 10 are destroyed. Further, the communication circuit 10
In the case of EEE1394 or the like, since indefinite data is not input during the insertion of the plug, the operation state of the communication circuit 10 is not adversely affected.

Although the embodiment of the present invention has been described with reference to IEEE 1394 as an example, the present invention is not limited to IEEE 1394, but also to USB (Universal Serial).
Bus) can be applied to other electronic devices using other communication standards.

In the embodiment of the present invention, an example of a plug including a power terminal has been described. However, in IEEE1394, a plug having only a signal line without a power terminal and a receptacle can be used. The invention is equally applicable.

It is not necessary to use an OMJ in a device that does not use an optical fiber, and the present invention can be applied to a mini jack using a normal mini jack.

[0037]

According to the first and second aspects of the present invention, it is possible to prevent the receiving section or the transmitting section from being electrically damaged when the plug is inserted. Further, malfunction of the communication circuit due to contact with another terminal during insertion of the plug can be prevented.

According to the third aspect of the present invention, since the receptacle itself also serves as a means for detecting the insertion state of the communication cable,
It is possible to reduce the number of components, the area occupied by components, etc. of the circuit board.

According to the fourth or fifth aspect of the present invention, the area occupied by the receptacle with respect to the surface area of the device can be reduced, which is effective for realizing the miniaturization of the device.

In the present invention, an example of a plug including a power supply terminal has been described. However, in IEEE1394, a plug and a receptacle having only a signal line not including a power supply terminal can be used. Can be applied.

In addition, the above-mentioned invention can be applied not only to IEEE1394 but also to USB (Universal Serial).
Bus) can be applied to other electronic devices using other communication standards.

It is not necessary to use an OMJ in a device that does not use an optical fiber, and the present invention can be applied to a mini jack using a normal mini jack.

[Brief description of the drawings]

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

FIGS. 2A and 2B are internal circuit diagrams of a contact portion 7 of the OMJ used in the present invention, wherein FIG. 2A shows a state when a plug is inserted, and FIG.

3A is a diagram showing a plug shape of a communication cable used in the present invention, and FIG. 3B is an external view of an OMJ used in the present invention.

FIG. 4 shows shapes of plug and receptacle electrodes according to the IEEE 1394 standard.

FIG. 5 is an example of the prior art in which the shapes of the plug and the receptacle are different from the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical mini jack (OMJ) 2 Electric plug 3 Switch (opening / closing means) 4 Standby circuit 5 Plug insertion detection signal 6 Control signal 7 Contact part inside OMJ 8 Front end circuit inside OMJ 9 Electric signal for optical communication 10 Communication circuit 11 Movable section 12 Fixed section 13 Terminal for detecting plug insertion state 14 Signal terminal 15 Power supply terminal 16 IEEE1394 standard plug 17 IEEE1394 standard receptacle 18 Receptacle side power electrode 19 Receptacle side signal electrode 20 Plug side electrode

Continuing on the front page (72) Inventor Yuji Ichikawa 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside (72) Inventor Masafumi Takahashi 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Daisuke Nakano 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Toru Ueda 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (5)

[Claims] 1. An electronic device having a function of attaching and detaching a communication cable, comprising: means for detecting that a plug of the communication cable is inserted into a receptacle attached to the electronic device; Opening and closing means for short-circuiting or opening a communication signal line between the receptacle and the communication circuit unit based on the condition.When the insertion is detected, the opening and closing means causes the opening and closing means to open and close the communication signal line between the receptacle and the communication circuit unit. An electronic apparatus, wherein a communication signal line is short-circuited, and in a state where insertion is not detected, the communication signal line between the receptacle and the communication circuit unit is opened by the opening / closing means. 2. The electronic device according to claim 1, further comprising: a unit that waits for a specific period based on the detection of the insertion by the detection unit, and the opening and closing unit after the specific standby period. An electronic device, wherein the communication signal line between the receptacle and the communication circuit unit is short-circuited. 3. The electronic device according to claim 1, wherein the detection unit is provided in the receptacle. 4. The electronic device according to claim 1, wherein the plug and the receptacle are small-sized single-headed plugs and receptacles corresponding to small-sized single-headed plugs, respectively. 5. The electronic device according to claim 4, wherein the receptacle is an optical mini jack (OMJ) that shares an optical signal and an electrical signal with plugs of the same shape.