JPH04347578A - Ac adapter - Google Patents

Abstract

PURPOSE:To provide an AC adapter which can automatically vary the output voltage in correspondence with a device which needs a DC power source without operating a changeover switch. CONSTITUTION:A Zener diode 14 is provided in a connector 26 of a device 24 side, which needs a DC voltage, and a circuit 22 for outputting a DC voltage corresponding to a voltage regulating reference voltage to be input from the connector of the device side, is provided. Thus, the reference voltage is set at the device 24 side, and the DC voltage to be output is regulated based on the set reference voltage.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an AC adapter.
In particular, the present invention relates to an AC adapter that makes it possible to change the output voltage depending on the device that requires a DC power source.

0002

[Prior Art] When using AV equipment such as radios, tape recorders, word processors, etc. with an AC power source other than a DC power source such as a dry battery or storage battery, it is necessary to use an AC adapter to step down the AC power source and convert it to DC power. There is. FIG. 3 shows a schematic circuit configuration of a conventional AC adapter. As shown in the figure, the conventional AC adapter 2 includes a plug 4 connected to an AC power source, a transformer rectifier circuit 6 that transforms and rectifies the AC power supplied from the plug 4, and a transformer rectifier circuit 6 that transforms and rectifies the transformer-rectified DC voltage. The voltage adjustment circuit 8 controls and outputs a constant voltage. The voltage adjustment circuit 8 includes a power transistor 10, a resistor 12, and a Zener diode 14.
It consists 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 moreover, each AV device has a DC voltage that is set by the Zener diode 14. Since the voltages are different, there is an inconvenience that different types of AC adapters must be prepared depending on the voltages. As a result, there is an inconvenience that the number of AC adapters that are not actually used increases.

0004

[Problems to be Solved by the Invention] In order to eliminate such inconveniences, an AC adapter is provided with a plurality of voltage adjustment circuits and a changeover switch for switching between the plurality of voltage adjustment circuits, so as to change the output voltage. AC adapters that can be changed have also been developed. However, such an AC adapter has the problem that the task of switching the switch is complicated, and if the switch is switched incorrectly, there is a risk that an incorrect voltage may be applied to the device.

The present invention was made in view of the above circumstances, and provides an AC adapter that can automatically change the output voltage according to the device requiring DC power without operating a changeover switch. The purpose is to provide.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the AC adapter of the present invention is provided with a reference voltage setting means on the device side that requires DC voltage, and a reference voltage setting means on the adapter side. The present invention is characterized in that it is provided with a circuit that outputs a DC voltage corresponding to a reference voltage for voltage adjustment inputted from the voltage setting means.

[0007]

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

[0008]

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

As shown in FIG. 1, an AC adapter 20 according to an embodiment of the present invention has a plug 4 connected to an AC power source.
, a transformer-rectifier circuit 6 that transforms and rectifies the AC power supplied from the plug 4, and a voltage adjustment circuit 22 that controls the transformer-rectified DC voltage to a constant voltage and outputs it. The transformer rectifier circuit 6 converts 100V to 20V, for example.
It is composed of a transformer circuit that steps down the voltage to about V, a rectifier circuit that rectifies the transformed AC voltage, and a smoothing circuit that smoothes the rectified DC voltage to some extent. In the present invention, the transformer rectifier circuit 6 The configuration is not limited.

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

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

Next, the specific structure of the output terminal of the AC adapter and the connector section of the device according to an embodiment of the present invention will be explained. 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 the cylindrical insertion end 34 of the plug 32. Output terminal 2
8a is attached in a ring shape to the inner circumferential surface of the insertion end 34, and when the insertion end 34 of the plug 32 is inserted into the fitting groove 36 formed in the connector section 26 of the device 24. ,
It is configured to be connected to a connecting terminal 30a that protrudes in the axial center of the fitting groove 36. Further, the output terminal 28b is attached in a ring shape to the outer peripheral surface on the proximal side of the insertion end 34, and the output terminal 28c is attached in a ring shape to the outer peripheral surface on the distal side of the insertion end 34, With the insertion end 34 of the plug 32 inserted into the fitting groove 36 formed in the connector section 26 of the device 24, the connection terminals 30b and 30c attached to the inner peripheral surface of the fitting groove 36 are inserted. However, they are each in a connected state.

By configuring the plug 32 and the connector section 26 in this manner, it is also possible to connect a conventional AC adapter plug to the connector section 26 of the device 24. In this case, in the conventional AC adapter plug, unlike the output terminals 28b and 28c of this embodiment, a single terminal is attached to the entire outer circumferential surface of the insertion end 34, so that the device side The connection terminal 30b and the connection terminal 30c become conductive, the Zener diode 14 is short-circuited, and the constant DC voltage set by the conventional AC adapter is supplied to the device without any problem.

[0014] Also, the plug 3 of the AC adapter of this embodiment
Even if the insertion end 34 in 2 is inserted into the fitting groove in the connector section of a conventional device in which the reference voltage setting means is not installed, the output terminal 28b will be in a non-contact state with the connection terminal on the device side ( In the connector section of the conventional device, a connection terminal corresponding to the connection terminal 30b of this embodiment is not attached, so that safety and compatibility are not compromised.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but 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 any means that provides a reference voltage to the voltage adjustment circuit 20 may be used. For example, it may be a fixed resistance.

[0016]

[Effects of the Invention] As explained above, the AC of the present invention
According to the adapter, by providing a reference voltage setting means in advance on each device side, by connecting the output terminal of the AC adapter of the present invention to the connector section of the device, each device can be adjusted without operating a changeover switch or the like. It becomes possible to automatically obtain the constant DC voltage required for the equipment,
There is no need to prepare an AC adapter for each device. Also, depending on the reference potential setting means installed on the device side,
Since the voltage output from the C adapter is automatically determined, it becomes possible to use the AC adapter without worrying about the voltage required by the device, improving usability. Furthermore, since the number of parts does not increase compared to conventional AC adapters, manufacturing costs do not increase. Furthermore, by making the structure of the connection part almost the same as that of the conventional one, compatibility with the conventional AC adapter is also ensured.

[Brief explanation of drawings]

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

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

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

[Explanation of symbols]

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

Claims (1)

[Claims] Claim 1: In an AC adapter that rectifies and adjusts the voltage of an AC power source and outputs a DC voltage, a reference voltage setting means is provided on the side of the device that requires the DC voltage, and a reference voltage setting means is provided on the side of the adapter that connects the adapter and the device. An AC adapter characterized in that it is provided with a circuit that outputs a DC voltage corresponding to a reference voltage for voltage adjustment inputted from a reference voltage setting means on the device side when the AC adapter is connected to the AC adapter.