Alternating current/direct current two-way switch

1. An AC/DC two-way switch to be connected between one of an AC power source and a DC power source and a load to control a power supply to the load, comprising:

a bi-directional semiconductor switch element having a transistor structure connected in series between a first input terminal to be connected to a power source and a first output terminal to be connected to the load;

a rectifying unit connected in parallel with the power source between the first input terminal and a second input terminal;

a power source unit for converting an output voltage from the rectifying unit into a stable voltage;

a controller for controlling an entire operation of the AC/DC two-way switch by using a power supplied from the power source unit; and

a driving unit for turning on the bi-directional semiconductor switch element in response to a control signal from the controller.

2. The AC/DC two-way switch of claim 1 , wherein the bi-directional semiconductor switch element includes inversely connected two switch elements each having a high voltage-withstanding vertical transistor structure.

3. The AC/DC two-way switch of claim 1 , wherein the bi-directional semiconductor switch element has a lateral single-gate transistor structure including:

a first electrode and a second electrode connected in series between the first input terminal and the first output terminal and formed on a surface of a substrate;

an intermediate potential unit having at least a portion formed on the surface of the substrate and having an intermediate potential with respect to the potential of the first electrode and that of the second electrode; and

a control electrode having at least a portion connected on the intermediate potential unit, the control electrode controlling the intermediate potential unit, and

wherein the intermediate potential unit and the control electrode are disposed at a position which allows a certain withstand voltage to be maintained with respect to the first electrode and the second electrode.

4. The AC/DC two-way switch of claim 1 , wherein the bi-directional semiconductor switch element has a lateral dual-gate transistor structure including:

a first electrode and a second electrode connected in series between the power source and the load and formed on a surface of a substrate; and

a first control electrode and a second control electrode having at least a portion formed on the surface of the substrate, each receiving an independent control signal, and

wherein the first control electrode and the second control electrode are disposed at a position which allows a certain withstand voltage to be maintained.

5. The AC/DC two-way switch of claim 1 , wherein the rectifying unit is a half-wave rectification circuit, which is operable when an anode of a diode included in the rectifying unit is connected to the first input terminal and a positive electrode of the DC power source is connected to the first input terminal.

6. The AC/DC two-way switch of claim 1 , further comprising:

a second rectifying unit connected in parallel with the load between the first output terminal and a second output terminal; and

a second power source unit for converting an output voltage from the second rectifying unit into a stable voltage,

wherein the controller controls the entire operation of the AC/DC two-way switch based on a power supplied from either one of the power source unit and the second power source unit.

7. The AC/DC two-way switch of claim 1 , further comprising:

a power type determination unit for determining whether a power source connected with the first input terminal and the second input terminal is the AC power source or the DC power source; and

a power type informing unit for displaying a determination result from the power type determination unit.

8. The AC/DC two-way switch of claim 7 , wherein, when a zero-cross of an AC voltage is detected, the power type determination unit determines that the AC power source is connected.

9. The AC/DC two-way switch of claim 8 , wherein, when it is determined by the power type determination unit that the AC power source is connected, the controller outputs a control signal for electrically connecting the bi-directional semiconductor switch element in synchronization with a zero-cross detection of the power type determination unit.

10. The AC/DC two-way switch of claim 1 , further comprising:

an auxiliary switch element having switching contacts, which is connected in parallel with the bi-directional semiconductor switch element.

11. The AC/DC two-way switch of claim 1 , further comprising:

an auxiliary switch element having switching contacts, which is connected in series to the bi-directional semiconductor switch element.

12. The AC/DC two-way switch of claim 1 , further comprising:

a communications function unit for transmitting and receiving a signal to and from an external device.

13. The AC/DC two-way switch of claim 12 , wherein the communications function unit detects a control signal from the external device connected to a power line, the control signal being overlapped with power to be transmitted.

14. The AC/DC two-way switch of claim 1 , further comprising:

a second bi-directional semiconductor switch element connected in series between the second input terminal and a second output terminal.

15. The AC/DC two-way switch of claim 1 , wherein the first output terminal and a second output terminal have a socket shape.