JP2804707B2 - AC adapter for electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC adapter for converting an AC voltage into a DC voltage and supplying power to an electronic device. Also, the present invention relates to an AC adapter that can be used even when connected with a DC cable outside the electronic device body.

[0002]

2. Description of the Related Art In recent years, as the power saving performance of a device and the performance of a secondary battery have been improved, some portable electronic devices such as a notebook personal computer (hereinafter referred to as a notebook personal computer) have been driven by a battery. Many have appeared. Such a battery-powered notebook computer
Because it is sometimes used on an office desk,
It can also be driven using an AC adapter.

Further, the shape of the AC adapter is made the same as that of the battery pack,
A device that can selectively store any of them has also been proposed. However, such an apparatus cannot be used with the AC adapter arranged outside the apparatus. Therefore, the present applicant has devised a system configuration shown in FIG. As shown in this figure, the notebook computer 50 has a battery storage section 81 on the side of the main body,
By storing and mounting the battery pack 61 here, the battery pack 61 can be operated by energy supplied from the battery pack 61. On one side of the battery pack 61, two DC voltage output terminals 78 and 7
9 is provided, and when housed in the battery housing portion 81, is pressed into contact with the terminals 76 and 77 on the main body side to be electrically connected.

[0004] An AC adapter 10 having the same shape as that of the battery pack 61 can be accommodated in the battery accommodating section 81, and the notebook computer 50 can be operated by a DC voltage supplied from the AC adapter 10. . A
The C adapter 10 converts an AC voltage input from the AC plug 12 into a DC voltage, and outputs a DC voltage from two DC voltage output terminals 16 and 18 provided on one side surface. These terminals are connected to the battery pack 6
As in the case of 1, when the battery is housed in the battery housing 81, it is pressed against the terminals 76 and 77 on the main body side,
Electrically connected. This state is shown in FIG. As shown in this figure, when the AC adapter 10 is stored in the battery storage section 81 of the main body and used, the notebook PC is a normal AC power supply type notebook personal computer.

On the other hand, as shown in FIG. 7, the AC adapter 10 can be used outside the notebook computer 50. In this case, the dedicated DC cable 82
DC input jack 52 provided on the side of the main body
And DC output jack 2 provided on the side of AC adapter
1, a DC voltage is supplied from the AC adapter 10 to the notebook computer 50. At this time, the battery pack 61 may or may not be attached to the battery storage section 81 as shown in the drawing.

As described above, the AC adapter 10 can be used while being attached to the main body, and can also be used outside the main body. On the other hand, when the battery pack 61 is used by driving, it is connected to the AC adapter 10 without removing the battery pack 61 to use the commercial power supply without removing the battery pack 61, or
The battery pack can now be charged, making it easier for users to use.

[0007]

In the above configuration,
The DC voltage output terminals 16 and 18 provided on the AC adapter 10 are generally electrically connected to the terminals 76 and 77 on the main body side in a press-contact manner. Therefore,
These two terminals 16 and 18 are connected to the AC adapter 10
Although it is provided at a position slightly depressed from the back of
It is directly exposed to the outside. For this reason, for example, when the + terminal of the two DC voltage output terminals 16 and 18 contacts the live part (metal part or the like) of the notebook computer main body, the Vcc side (+ side) and the ground side (−) Side) in many cases. This is because the case of the notebook personal computer is often grounded for noise suppression. Generally, the housing of such a notebook computer is
Although it is molded with resin, its surface is metal-plated and further painted to prevent noise. Therefore, if the outermost coating is peeled off and the plated surface is exposed, if the + side DC output terminal of the AC adapter 10 comes into contact with this portion, a short circuit occurs and the AC adapter or a circuit inside the main body may be damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. When an AC adapter that can be used by being housed inside an electronic device body is used outside the electronic device, the AC adapter is provided on the AC adapter. An object of the present invention is to provide an AC adapter capable of safely and reliably preventing a short circuit caused by contact between a provided DC voltage output terminal and a live part of an electronic device body.

[0009]

An electronic device AC adapter according to the present invention can be used while being stored in a battery storage portion of an electronic device main body, and is connected to the main body by a DC cable. A DC voltage output terminal for supplying a DC voltage to the electronic device main body in a state where the DC adapter is stored in the battery storage portion; A cable connection terminal for connecting a cable,
When used outside the electronic device, detecting means for detecting the connection of the DC cable to the cable connection terminal, in response to the detection of the connection of the DC cable by the detecting means, And a switch for cutting off the DC voltage output from the DC voltage output terminal.

[0010] The AC for electronic equipment according to the invention of claim 2
The adapter according to claim 1, wherein a negative pole side of the DC circuit in the electronic device is connected to a housing of the electronic device and grounded, and the switch is connected to a positive terminal of the DC voltage output from the DC voltage output terminal by the switch. It is characterized in that only the pole side is cut off.

[0011]

In the AC adapter for an electronic device according to the first aspect of the present invention, when the AC adapter is disposed outside the electronic device and used, the cable connection terminal of the AC adapter is used to connect to the electronic device main body. Is detected, this is detected, and the DC voltage output from the DC voltage output terminal for supplying the DC voltage to the electronic device main body at the time of attachment to the battery housing is cut off.

An AC for electronic equipment according to the invention of claim 2
In the adapter, when the negative pole side of the DC circuit in the electronic device is connected to the housing of the electronic device and grounded, only the positive pole side of the DC voltage output from the DC voltage output terminal is cut off.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 shows a main part of an AC adapter according to an embodiment of the present invention. This AC adapter 1
0 has the same external appearance as that shown in FIG.
(Hereinafter, simply referred to as + side output terminal 18) and-side DC voltage output terminal 16 (hereinafter, simply referred to as-side output terminal 16).
Is provided. The + output terminal 18 is connected to the switch 15
Is connected to one end of a secondary coil of the transformer 13 via a diode 14 connected in the forward direction.
6 is connected to the other end of the secondary coil of the transformer 13 via the switch 17. The primary coil of the transformer 13 is connected to the AC plug 12 that can be connected to an outlet of a general commercial power supply.

The AC adapter 10 has a DC plug 23 to which a DC plug 23 of a dedicated DC cable 82 can be connected.
An output jack 21 is provided. This DC output jack 21 has three terminals a, as shown in FIG.
b and c, of which terminal a is a + side output terminal,
Terminal b is a negative output terminal, and terminal c is a terminal for detecting plug connection. The + output terminal a is connected between the switch 15 and the diode 14, and the DC voltage Vcc is applied to this. On the other hand, the negative output terminal b is connected to the transformer terminal of the switch 17 and is kept at the ground level.

Further, this circuit is provided with a switch drive circuit 19, and a DC cable presence / absence signal 2 from the connector connection detection terminal c of the DC output jack 21 described above.
2, the opening and closing of the switches 15 and 17 are controlled.

The operation of the AC adapter having the above configuration will be described.

First, the operation when the AC adapter 10 is used while housed in the battery housing section 81 (FIG. 5) of the notebook computer 50 will be described.

In this case, as shown in FIG. 6, when the AC adapter 10 is completely housed in the notebook personal computer main body, the output terminals 18 and 16 are connected to the terminal 77 on the main body side as shown in FIG. And 76. In this state, when the AC plug 12 is inserted into the outlet of the commercial power supply, a predetermined DC voltage Vcc is applied to the secondary coil of the transformer 13.
Occurs. At this time, the DC output jack 21
Since the DC plug 23 of the C cable 82 is not inserted, the terminal c is in contact with the terminal b as shown in FIG. For this reason, the switch drive circuit 19
A DC cable presence / absence signal 22 inputted to the terminal indicates a cable absence state.

The switch drive circuit 19 that detects this
Controls the switches 15 and 17 to be in the closed state. As a result, the DC voltage Vcc generated in the secondary coil of the transformer 13 is applied to the output terminals 18 and 16,
It will be supplied to the main body side.

Next, the operation when the AC adapter 10 is used outside the notebook computer 50 will be described.

In this case, the DC input jack 52 of the notebook computer 50 is
(FIG. 7) and the DC output jack 21 of the AC adapter 10 are connected. At this time, as shown in FIG.
By the insertion of the plug 23, the contact between the terminal b and the terminal c of the DC output jack 21 is cut off, and the DC cable presence / absence signal 22 from the terminal c indicates that the cable is present.

The switch drive circuit 19 which detects this
Controls the switches 15 and 17 to open. As a result, the DC voltage output from the output terminals 18 and 16 is cut off. For this reason, even if the + side output terminal 18 comes into contact with a metal part or the like of the main body housing part, a short circuit does not occur with the ground.

Next, a detailed configuration of the switch drive circuit 19 and the switches 15 and 17 in FIG. 1 will be described.

As shown in FIG. 2, a transistor 31 is used as the switch 15, and a transistor 43 is used as the switch 17. The collector of the transistor 31 is connected to the + output terminal 18, and the emitter is connected to Vcc. The base of the transistor 31 is connected to the emitter of the transistor 31 via a resistor 34 and to the terminal c of the DC output jack 21 via a resistor 35. On the other hand, the collector of the transistor 43 is connected to the negative output terminal 16, the emitter is grounded, and connected to the terminal b of the DC output jack 21.
The terminal a of the DC output jack 21 is directly connected to Vcc.

In this circuit, a transistor 37 is provided, the emitter of which is connected to Vcc, the base is connected via a resistor 36, and the collector is connected to a resistor 41.
And the resistor 42 is connected to the emitter of the transistor 43. The connection point between the resistors 41 and 42 is connected to the base of the transistor 43. Transistor 37
Is connected to a terminal c of the DC output jack 21 via a resistor 38 and a diode 39.

The operation of the switch drive circuit 19 having the above configuration will be described. DC plug 23 is DC output jack 2
1 is not inserted into the terminal 1, the terminal c is connected to the terminal b.
And the ground level. Therefore, a current flows from Vcc through the resistors 34 and 35, and the transistor 31
Is turned on, and the DC voltage Vcc is applied to the + output terminal 18. At this time, the resistance 36 and the resistance 3
8, a current flows to the ground side via the diode 39, the terminals c and b, and the transistor 37 is also turned on. As a result, a current flows through the resistor 41, and the transistor 43 is also turned on. Therefore, the negative output terminal 16 is connected to the ground side.

On the other hand, when the DC plug 23 is inserted and connected to the DC output jack 21, the terminals c and b of the DC output jack 21 are separated from each other, and no current flows through the resistors 34 and 35. As a result, the transistor 31 is turned off, and the connection between the + output terminal 18 and Vcc is disconnected.
At this time, simultaneously, the resistors 36 and 38 and the diode 39
The current in the path of FIG. As a result, the current of the resistor 41 does not flow, and the transistor 43 is also turned off. Therefore, the negative output terminal 16 is disconnected from the ground side.

Next, an outline of the internal power supply circuit of the notebook computer 50 will be described.

As shown in FIG.
0, a DC input jack 52 is provided, and its + input terminal a is connected to an internal load circuit 57 via a diode 55 and a switch 56 connected in the forward direction. On the other hand, the negative terminal b of the DC input jack 52 is
It is grounded and connected to the housing 51. DC
The plug connection detection terminal c of the input jack 52 is connected to the charge / discharge controller 65.

This figure shows a state in which the battery pack 61 is housed and mounted, and the output terminal 78 connected to the + side of the battery 62 and the output terminal 7 connected to the-side of the battery 62.
Numeral 9 is configured to be in pressure contact with terminals 76 and 77 on the main body side, respectively. The negative terminal 77 is grounded and connected to the housing 51, and the positive terminal 76 is connected to the switch 5.
9 is connected between the switch 56 and the diode 55. The charge / discharge controller 65 includes a DC plug detection signal 73 input from the DC input jack 52,
Based on a power switch ON / OFF signal 74 input according to the ON / OFF of a main power switch (not shown), the control signals 71 and 72 control the opening and closing operations of the switches 56 and 59.

The operation of the main body side power supply circuit configured as described above will be described.

When the DC plug 54 of the DC cable 82 is
When not connected to the input jack 52, the terminals b and c of the DC input jack 52 are in contact, and the DC plug detection signal 73 indicates that there is no DC plug. Thereby, the charge / discharge controller 65 is connected to the external AC adapter 1.
It is determined that 0 is not connected, and the power switch on / off signal 74 is checked. As a result, when the main power switch is on, both the switches 56 and 59 are closed. As a result, the DC voltage is supplied from the battery pack 61 to the load circuit, and the device is started. On the other hand, when the main power switch is off, the switches 56 and 59 are both opened. As a result, power is not supplied to the load circuit 57, and the power off state is maintained.

On the other hand, the DC plug 54 of the DC cable 82
Is inserted and connected to the DC input jack 52,
The DC plug detection signal 73 from the terminal c of the C input jack 52 indicates that a DC plug is present. The charge / discharge controller 65 that has detected this determines that the external AC adapter 10 is connected, and checks the power switch on / off signal 74. As a result, when the main power switch is on, the switch 56 is closed and the switch 59 is open. As a result, a DC voltage is supplied from the external AC adapter 10 through the DC input jack 52 to the load circuit 57.
And the device is activated. On the other hand, when the main power switch is off, the switch 56 is open and the switch 59 is closed. As a result, the DC current input from the external AC adapter 10 is input to the battery pack 61 via the switch 59 and the battery 62
Is charged. However, when the battery 62 is fully charged, the switch 5 is controlled by the charge / discharge controller 65.
9 is turned off and charging is not performed.

Although the power supply by the external AC adapter 10 in a state where the battery pack 61 is stored in the battery storage section 81 of the notebook computer 50 has been described with reference to FIG.
Can be stored and mounted in the battery storage section 81, and the apparatus can be driven using this as a power source. In this case,
The AC adapter 10 is mounted in place of the battery pack 61, and the output terminals 16 and 18 of the AC adapter 10 are connected to terminals 76 and 77 on the main body side, respectively. The switch 5 is controlled by the charge / discharge controller 65.
6 and 59 are controlled to open and close in response to the power switch on / off signal 74, so that the DC voltage supply to the load circuit 57 is controlled.

In the above embodiment, the AC adapter 10
In the case where the DC plug 23 is inserted into the DC input jack 21, the switches 15 and 17 are both disconnected, and the output terminals 18 and 16 are both disconnected. However, as described with reference to FIG. When the minus side of the DC circuit is grounded to the housing, only the switch 15 of the AC adapter 10 may be turned off and only the plus side output terminal 18 may be disconnected. In this case, even if the switch 17 on the ground side remains ON, the + output terminal 18
Does not cause a short circuit when it comes into contact with the housing of the notebook computer 50, and the same effect as when both switches are turned off can be obtained.

[0037]

As described above, according to the present invention,
When an AC adapter that can be used even when housed and mounted inside the electronic device body is used by arranging it outside the electronic device body,
When a DC cable for connecting to the electronic device body is connected to the AC adapter, the output of the DC output terminal exposed on the outer surface of the AC adapter is automatically cut off. Therefore, even when the DC output terminal of the AC adapter is inadvertently in contact with the live part of the main body, a short circuit does not occur, and the device can be prevented from being damaged due to an unexpected accident. is there.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a circuit configuration of an AC adapter according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a detailed circuit configuration of a switch drive circuit 19 and switches 15 and 17 in FIG.

FIG. 3 is a diagram schematically showing the structure and function of a DC output jack 21 in FIG.

FIG. 4 is a block diagram showing a main part of an internal circuit of the notebook computer 50 in FIG.

FIG. 5 is an external perspective view of the notebook computer 50, the AC adapter 10, and a battery pack 61.

FIG. 6 is an external perspective view showing a state in which the AC adapter 10 is housed and mounted inside the notebook computer 50.

FIG. 7 shows an AC adapter 10 provided outside the notebook computer main body.
FIG. 3 is a diagram for explaining a state in which both are arranged and connected between them by a dedicated DC cable.

[Explanation of symbols]

 Reference Signs List 10 AC adapter 11, 51 Housing 15, 17 Switch 16, 18 DC voltage output terminal 19 Switch drive circuit 21 DC output jack 23, 54 DC plug 50 Notebook PC 52 DC input jack 61 Battery pack 81 Battery storage section 76, 77 DC Voltage input terminal (main unit side)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 1/26-1/32 H01R 31/06 H02M 1/10

Claims (2)

(57) [Claims] 1. An AC adapter that can be used in a state of being stored in a battery storage portion of an electronic device main body and that can be used even when disposed outside the electronic device by being connected to the main body with a DC cable. A DC voltage output terminal for supplying a DC voltage to the electronic device main body while being stored in the battery storage portion; a cable connection terminal for connecting the DC cable; used outside the electronic device Detecting means for detecting the connection of the DC cable to the cable connection terminal, in response to the detection of the connection of the DC cable by the detection means, An AC adapter for electronic equipment, comprising: a switch for cutting off a DC voltage output. 2. The DC voltage output from the DC voltage output terminal according to claim 1, wherein a negative pole side of the DC circuit in the electronic device is connected to a housing of the electronic device and grounded, and the switch is used to control a DC voltage output from the DC voltage output terminal. An AC adapter for electronic equipment, characterized in that only the positive pole side of the AC adapter is cut off.