JP3235114B2 - AC adapter - 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,
In particular, the present invention relates to an AC adapter that can change an output voltage according to a device that requires a DC power supply.

[0002]

2. Description of the Related Art When an AV device such as a radio, a tape recorder, or a word processor is used with an AC power supply other than a DC power supply such as a dry cell or a storage battery, it is necessary to use an AC adapter for stepping down the AC power supply and converting the AC power supply to DC. There is. FIG. 3 shows a schematic circuit configuration of a conventional AC adapter. As shown in the figure, a conventional AC adapter 2 includes a plug 4 connected to an AC power supply, a transformer rectifier circuit 6 for transforming and rectifying the AC power supplied from the plug 4, and a transformer rectified DC voltage. And a voltage adjusting circuit 8 for controlling and outputting the voltage at a constant voltage. The voltage adjustment circuit 8 includes a power transistor 10, a resistor 12, and a Zener diode 14.
It is composed of

However, in such an AC adapter 2, the DC voltage output from the output terminal 16 is a single type of constant voltage set by the Zener diode 14, and each of the AV devices has a required DC voltage. Since the voltages are different, there is a disadvantage that different types of AC adapters must be prepared according to the voltages. As a result, AC that is not actually used
There is a disadvantage that the number of adapters increases.

[0004]

In order to solve such inconveniences, the AC adapter is provided with a plurality of voltage adjustment circuits, and a changeover switch for switching the plurality of voltage adjustment circuits is provided to reduce the output voltage. AC adapters that can be changed have also been developed. However, such an AC adapter has a problem that the operation of switching the changeover switch is complicated, and there is a possibility that an erroneous switching may cause the device to apply an erroneous voltage.

The present invention has been made in view of such circumstances, and has developed an AC adapter capable of automatically changing an output voltage according to a device requiring a DC power supply without operating a changeover switch. The purpose is to provide.

[0006] To achieve the above object, the AC
The adapter is connected to a circuit that operates based on a DC voltage of a predetermined voltage applied through a power supply terminal, and is connected through a voltage setting terminal, and based on a current from the voltage setting terminal.
And reference voltage setting means for setting a predetermined reference voltage.
An AC adapter connected to a device for converting an AC voltage supplied from an AC power supply into a DC voltage.
A flow circuit, a first terminal connected to a voltage setting terminal of the device when the plug is connected to the device, the first terminal being provided on a plug attached to and detached from the device; If the terminal is connected to the voltage setting terminal of the device to adjust the converted DC voltage by the rectifier circuit, to the predetermined reference <br/> voltage that will be set by the reference voltage setting means of the device A voltage adjustment circuit, provided on the plug, a terminal connected to a power supply terminal of the device when the plug is connected to the device, and the terminal is connected to the power supply terminal when the plug is connected to the device; A second terminal for applying the DC voltage of the predetermined voltage to the device via the power supply terminal.

[0007]

According to the AC adapter of the present invention, since the reference voltage setting means is provided in the connector on the device side requiring a DC voltage, the output terminal of the AC adapter is connected to the connector on the device side. The reference voltage is set on the device side, and the DC voltage output is adjusted on the adapter side based on the set reference voltage. Therefore, by providing the reference voltage setting means on each device side in advance,
By connecting the output terminal of the AC adapter of the present invention to the connector section of the device, it becomes possible to automatically obtain a constant DC voltage required for each device, and the A
There is no need to prepare a C adapter.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an AC adapter according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic circuit configuration diagram of an AC adapter according to one embodiment of the present invention,
FIG. 2 is a schematic sectional view showing a connection state between an output terminal of an AC adapter and a connector section of the device according to one embodiment of the present invention.

As shown in FIG. 1, an AC adapter 20 according to an embodiment of the present invention includes a plug 4 connected to an AC power supply.
A rectifying circuit 6 for transforming and rectifying the AC power supplied from the plug 4, and a voltage regulating circuit 22 for controlling the transformed and rectified DC voltage to a constant voltage and outputting the same. The transformer rectifier circuit 6, for example,
It is composed of a transformer circuit for stepping down to about 0 V, a rectifier circuit for rectifying the transformed AC voltage, a smoothing circuit for smoothing the rectified DC voltage to some extent, and the like.
The configuration of the transformer rectifier circuit 6 is not limited.

In this embodiment, the voltage adjusting circuit 22 includes the power transistor 10 and the resistor 12.
The Zener diode 14 as a reference voltage setting means used in the conventional voltage adjusting circuit 2 is mounted in a connector section 26 of a device 24 such as an AV device requiring a DC voltage. The connector 26 has connection terminals 30 a to 30 c connected to output terminals 28 a to 28 c of the AC adapter 20.
Are mounted, and the Zener diode 14 is connected between the connection terminal 30b and the connection terminal 30c.

The output terminal 2 of the output terminal of the AC adapter 20
As shown in FIG. 1, 8a to 28c are connected to connection terminals 30a to 30c of the connector 26, respectively.
The reference voltage set by the Zener diode 14 as the reference voltage setting means acts as the base voltage of the power transistor 10, and the output terminals 28a and 28c
And outputs a constant DC voltage required by the device 24. Since the reference voltage set by the Zener diode 14 differs depending on the type of the device 24, the device 2
Select Zener diode 14 according to 4 types,
It is necessary to mount the Zener diode 14 on the connector 26 of the device 24 in advance.

Next, a specific structure of the output terminal of the AC adapter and the connector of the apparatus according to one embodiment of the present invention will be described. As shown in FIG. 2, the output terminals 28a to 28c of the AC adapter 20 are formed on the inner and outer peripheral surfaces of a cylindrical insertion end 34 of the plug 32. Output terminal 2
8a is mounted in a ring shape on the inner peripheral surface of the insertion end 34, and the insertion end 34 of the plug 32 is inserted into a fitting groove 36 formed in the connector 26 of the device 24. ,
A connection state is established with the connection terminal 30a protruding in the center of the fitting groove 36 in the axial direction. The output terminal 28b is mounted on the outer peripheral surface of the proximal end of the insertion end 34 in a ring shape, and the output terminal 28c is mounted on the outer peripheral surface of the distal end of the insertion end 34 in a ring shape. With the insertion end 34 of the plug 32 inserted into the fitting groove 36 formed in the connector part 26 of the device 24, the connection terminals 30 b and 30 c mounted on the inner peripheral surface of the fitting groove 36 are connected. On the other hand, they are connected.

With such a structure of the plug 32 and the connector section 26, a plug of a conventional AC adapter can be connected to the connector section 26 of the device 24. In this case, in the plug of the conventional AC adapter, the output terminal 28b and the output terminal 28c of the present embodiment are different.
Since a single terminal is mounted on the entire outer peripheral surface of the insertion end 34, the connection terminal 30b and the connection terminal 30c on the device side are in a conductive state, the Zener diode 14 is short-circuited, and the setting with the conventional AC adapter is performed. The supplied constant DC voltage is supplied to the device side without any problem.

The plug 3 of the AC adapter according to the present embodiment
2, the output terminal 28b is in a non-contact state with the connection terminal on the device side even if the insertion end portion 34 in 2 is inserted into the fitting groove in the connector portion of the conventional device on which the reference voltage setting means is not mounted (see FIG. In the connector part of the conventional device, a connection terminal corresponding to the connection terminal 30b of the present embodiment is not mounted), so that safety and compatibility are not impaired.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the reference voltage setting means is not limited to the Zener diode 14, but may be any means for providing a reference voltage to the voltage adjustment circuit 20. For example, a fixed resistor may be used.

[0016]

As described above, according to the present invention,
According to the adapter, by providing the reference voltage setting means on each device side in advance, by connecting the output terminal of the AC adapter of the present invention to the connector portion of the device, each switch can be operated without operating a changeover switch or the like. It is possible to automatically obtain the constant DC voltage required for the device,
There is no need to prepare an AC adapter for each device. Further, according to the reference potential setting means mounted on the device side, A
Since the voltage output from the C adapter is automatically determined, the AC adapter can be used without worrying about the voltage required by the device, and the usability is improved. Furthermore, since the number of parts does not increase as compared with the conventional AC adapter, the manufacturing cost does not increase. Furthermore, by adopting a structure of the connection part substantially similar to the conventional one, compatibility with the conventional AC adapter is also ensured.

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view showing a connection state between an output terminal of an AC adapter and a connector section of the device according to one embodiment of the present invention.

FIG. 3 is a schematic circuit configuration diagram of a conventional AC adapter.

[Explanation of symbols]

 14 Zener diode 20 AC adapter 22 Voltage adjustment circuit 24 Device 26 Connector part 28a Output terminal 28b Output terminal 28c Output terminal

Claims (1)

(57) [Claims] A circuit which operates based on a DC voltage of a predetermined voltage applied through a power supply terminal, is connected via a voltage setting terminal, and is connected to a circuit based on a current from the voltage setting terminal.
And reference voltage setting means for setting a predetermined reference voltage.
An AC adapter connected to a device that converts an AC voltage supplied from an AC power supply into a DC voltage
A rectifier circuit, a first terminal that is provided on a plug that is attached to and detached from the device, and that is connected to the voltage setting terminal of the device when the plug is connected to the device; When the terminal is connected to the voltage setting terminal of the device, the DC voltage converted by the rectifier circuit ,
A voltage adjustment circuit for adjusting prior Symbol predetermined reference voltage that will be set by the reference voltage setting means of the device, provided on the plug, connected to the power supply terminal of the device when the plug is connected to said device An AC adapter having a second terminal that, when connected to the power terminal, applies the adjusted DC voltage of the predetermined voltage to the device via the power terminal.