Abstract:
A power supply device having a standby power cutoff structure, comprises: a power supply unit which has a plug connected to a socket, converts an external power for a power supply target device, and generates self-operating power; a connector unit which includes a power supply terminal to supply power to the power supply target device, and opens or blocks a power supply path between the external power and the power supply unit in response to a switching driving signal received from the power supply unit; and a cable for connecting the power supply unit and the connector unit, wherein the power supply unit checks the state of power supplied through a switching unit to output the switching driving signal to the switching unit such that the switching unit cuts off a power supply when the power supply target device is fully charged or the power supply device is turned off.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage application under 35 U.S.C. §371 of an International application filed on Mar. 17, 2011 and assigned application No. PCT/KR2011/001869, and claims the benefit under 35 U.S.C. §365(b) of a Korean patent application filed Mar. 31, 2010 in the Korean Intellectual Property Office and assigned application No. 10-2010-0029047, and a Korean patent application filed Jun. 16, 2010 in the Korean Intellectual Property Office and assigned application No. 10-2010-0057223, the entire disclosure of each of which is hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a power supply apparatus for supplying power to various electronic products requiring DC power, such as a conventional notebook, netbook, radio, CD player and the like, and more particularly to a technology which has a function of cutting off standby power when a power supply of a product is turned “off” and automatically cuts off the standby power when the power supply of the product is turned “off”. 
     BACKGROUND ART 
     In general, a power supply apparatus for supplying power to a product (notebook, netbook or the like) having a self charging battery or a product (radio, CD player or the like) having no charging battery includes a connector connected to the corresponding product, a plug connected to commercial AC power and the like, and has a structure of converting the commercial AC power to DC power suitable for the corresponding product and providing the converted DC power to the product through the connector. 
     However, the power supply apparatus has a problem in that power is wasted since standby power is continuously generated even in a state where a power supply of the product is turned “off” or a battery is fully charged. 
     Due to the above problem, a program for legally regulating standby power is recently prepared all over the world including Korea. The standby power of the power supply apparatus has been restricted to 1 W from 2010 in Korea, and the standby power was restricted to 1 W or less in 2010 and a bill of restricting the standby power to 0.5 W has been passed and is due to take effect in Europe in 2013. 
     Accordingly, it is greatly required to provide a method of minimally maintaining or cutting off the standby power in the power supply apparatus. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     The present invention has been made to solve the above mentioned problems occurring in the prior art and provides a power supply apparatus capable of completely cutting off standby power without unplugging an electronic product when a battery of the electronic product is fully charged and when a power supply of the electronic product is turned “off”. 
     The present invention provides a power supply apparatus capable of completely cutting off standby power of an electronic product in an off state and automatically switching the electronic product to an on state when a power supply of the electronic product is turned on if the corresponding electronic product is required to be in the on state. 
     Technical Solution 
     In accordance with an aspect of the present invention, there is provided a power supply apparatus with a standby power cut-off structure, the power supply apparatus including: a power supply unit for receiving external power supplied through a plug to convert the external power to power suitable for a power supply target apparatus and generating its own operation power of the power supply apparatus, the power supply unit including the plug connected to an outlet to receive the external power; a connector unit including a power supply terminal connected to a connection terminal of the power supply target apparatus to supply power to the power supply target apparatus, and a switching unit for establishing or blocking an electric conduction of a power supply path through which the external power is provided to the power supply unit by a drive of a solenoid according to a switching driving signal provided from the power supply unit and a mechanical movement according to the drive of the solenoid, the switching unit being installed in the corresponding power supply path between the external power and the power supply unit; and a cable for connecting the power supply unit and the connector unit, wherein the power supply unit identifies a supply state of power provided through the switching unit, outputs the switching driving signal to the switching unit when it is determined, through the identified supply state, that a battery of the currently connected power supply target apparatus is fully charged and/or a power supply is turned off, and allows the switching unit to cut off the power supply. 
     Advantageous Effects 
     As described above, the present invention cuts off input power to a corresponding product to make standby power zero when a power supply of a notebook or a netbook is turned “off” or when a battery is fully charged and also turns “off” a power supply of electronic products (radio, CD player and the like) to make the standby power zero, so that unnecessary power consumption can be prevented. Further, a power supply apparatus according to the present invention is automatically switched to an on state when the electronic product is required to be in the on state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic external structure diagram of a power supply apparatus with a standby power cut-off structure according to an embodiment of the present invention. 
         FIG. 2  is an internal circuit block diagram of a power supply apparatus with a standby power cut-off structure and a related product according to an embodiment of the present invention. 
         FIGS. 3 to 7  are detailed plane views and side views of an example of a switching unit in  FIG. 1  or  FIG. 2 . 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     In the following description, a detailed explanation of known related functions and constitutions may be omitted to avoid unnecessarily obscuring the subject matter of the present invention. Further, terms which will be described below are defined considering functions according to the present invention, and may vary depending on an intention of the user and operator or a convention. Therefore, the definition should be made based on the contents throughout the specification. 
     The present invention proposes a power supply apparatus having a function of completely cutting off standby power when a power supply of an electronic product (notebook, netbook and the like) using a charging battery is turned “off” and a battery is fully charged or when a power supply of an electronic product (radio, CD player and the like) using no charging battery is turned “off” and a power plug is plugged into an outlet. 
       FIG. 1  is a schematic external structure diagram of a power supply apparatus with a standby power cut-off structure according to an embodiment of the present invention,  FIG. 1A  illustrates a structure of the power supply apparatus in a state where the power supply apparatus is not connected to a product, and  FIG. 1B  illustrates a structure of the power supply apparatus in a state where the power supply apparatus is connected to a product  300  (notebook, netbook, radio or the like). Referring to  FIG. 1 , the power supply apparatus according to the present invention has a plug configured to be insertable in an outlet to receive commercial AC power, and includes a power supply unit  200  for converting the commercial AC power to DC power suitable for the product  300  and generating its operation power, a connector unit  100  connected to the product  300 , and a cable  120  for connecting the power supply unit  200  and the connector unit  100 . 
     At this time, the connector unit  100  includes +/− power supply terminals  101  and  102  configured to be inserted in a connection terminal of the product  300 , and a switching unit  280  installed in a power supply path between the commercial AC power and the power supply unit  200  and configured to establish or block an electric conduction of the corresponding power supply path by a drive of a solenoid according to a switching control signal provided from the power supply unit  200  and a mechanical movement of a contact according to the drive of the solenoid. 
     When the switching unit  280  includes a knob  219  installed in a contact surface between the product  300  and the switching unit  280  when the connector unit  100  is connected to the product  300  and configured to be pressed. The knob  219  is configured to return to an original state by a knob spring  281  described below in a state where the connector unit  100  is not connected to the product. A contact of the switching unit  280  is mechanically configured to additionally move to a position for establishing an electric conduction of the power supply path by an initial press of the knob  219 . Further, the switching unit  280  may include a manual control switch  295  configured to manually turn “on” or “off” a power supply which will be described below. Similarly, the manual control switch  295  is configured to achieve the mechanical movement of the contact of the switching unit  280 . At this time, when the knob  219  is initially pressed, the manual control switch  295  is mechanically configured to move to a position in an on-state through an interworking, and it may be mechanically configured that a position movement according to an off-state and the on-state does not influence the movement of the knob  219  since a subject of the position movement is the manual control switch  295 . 
     The power supply unit  200  identifies a supply state of power provided via the switching unit  280 . When it is determined through the supply state that the currently connected product is in a state where a battery is fully charged or a power supply is turned off, the power supply unit  200  outputs a switching control signal to the switching unit  280  and allows the switching unit  280  to cut off the power supply. Further, the power supply unit  200  identifies whether operation power is provided from the corresponding connected product through the power supply terminal of the connector unit  100 . When the operation power is provided, the power supply unit  200  outputs the switching control signal to the switching unit  280  and allows the switching unit  280  to restart the power supply. 
     Hereinafter, configurations and operations of the connector unit  100  and the power supply unit  200  will be described in more detail with reference to the accompanying drawings. First, a mechanical structure of and the switching unit  280  installed in the connector unit  100  and an operation according to the mechanical structure will be described in more detail with reference to  FIGS. 3 to 7 . 
       FIGS. 3 to 7  are detailed plane structure views and side structure views of an example of the switching unit in  FIG. 1  or  FIG. 2 ,  FIG. 3  illustrates a state of the switching unit  280  when the initial connector unit  100  is not connected to the product  300 ,  FIG. 4  illustrates a state of the switching unit  280  while the connector unit  100  is connected to the product  300 , that is, the knob  219  is initially pressed,  FIG. 5  illustrates a state where the knob  219  is completely pressed,  FIG. 6  illustrates a state of the switching unit  280  by a power cut-off operation or a manual off control, and  FIG. 7  illustrates a state of the switching unit  280  while the connector unit  100  is separated from the product  300 . 
     Referring to  FIG. 1  and  FIGS. 3 to 7 , the switching unit  280  includes the knob  219  located in a predetermined position in the connector  100  and pressed in a D direction to supply main power to the power supply unit  200  when the connector unit  100  is inserted in the product  300 , and the knob spring  281  for returning the knob  219  to an original position when the knob  219  is released in a C direction. 
     Further, the switching unit  280  includes a cam lever  282  for pushing a cam  294  so that the cam  294  moves in an A direction according to a press of the knob  219 , and a lever spring  283  for returning the cam lever  282  to an original position after the cam lever  282  pushes the cam  294 . 
     Meanwhile, when the cam lever  282  hits the cam  294 , the cam  294  moves in the A direction and a slide  293  of a metal material integrally formed with the cam  294  is drawn and attached to a core  287  by force of a magnet  288  integrally formed with the core  287 , so that the cam  294  finally remains in the position moved in the A direction. At this time, a camp spring  292  for returning the cam  294  to an initial position in a B direction is installed in the cam  294 . When the cam  294  is attached to the core  287  by magnetic force of the magnet  288 , a state where the cam spring  292  is attached to the core  287  is maintained by configuring an intensity of the corresponding magnetic force to be stronger than that of restitutive force by the cam spring  292 . 
     Further, a striker  291  made of an insulation material integrally formed with the cam  294  is provided and the striker  291  presses an elastic contact  286  when the cam  294  moves in the A direction, so that the elastic contact  286  is connected with a fixed contact  285 . Through the connection between the elastic and fixed contacts  285  and  285 , the power supplied through the switching unit  280  is provided and blocked. 
     Moreover, when a current flows to the solenoid  284  in one direction to open the contact in a state where the fixed contact  285  and the elastic contact  286  are connected, repulsive force with the magnet  288  is generated and the cam spring  292  returns in the B direction, thereby the contacts are separated from each other. 
     Describing an operation of the switching unit  280  having such a configuration, when the connector unit  100  is connected to the electronic product such as a notebook, a netbook or the like, the knob  219  enters in the D direction and the cam lever  282  upwardly pushes the cam  294  as illustrated in  FIG. 4 , so that the slide  293  made of a metal conductor integrally formed with the cam  294  is taken by attractive force of the magnet  288  integrally formed with the core  287 . Accordingly, the striker  291  made of an insulation material integrally formed with the cam  294  moves in the A direction, and thus the fixed contact  285  and the elastic contact  286  are connected, thereby supplying power. Further, when the knob  219  pushes the cam lever  282  and moves downwardly, the lever  282  returns to an original position by the lever spring  283 , and the state illustrated in  FIG. 5  is maintained. 
     In such a state, as illustrated in  FIG. 6 , a micom (micom u 2  of  FIG. 2  described below) determines, through a current flowing in the power supply path, whether a power supply of the product such as the corresponding notebook, netbook or the like is turned off and a battery is being charged. When the battery is fully charged and a supply current is equal to or smaller than a reference current i 1 , the micom applies a voltage to one direction of the solenoid coil  284 , and repulsive force is generated. Then, the slide  293  pulls the cam  294  in the B direction by the cam spring  292 , and thus the striker  291  returns to an original position and the fixed contact  285  and the elastic contact  286  are separated from each other, so that input power is cut off and standby power is interrupted. 
     At this time, the manual control switch  295  in a cam knob type integrally formed with the cam  294  so as to turn on the power supply moves in the B direction, and the user can discriminate a current on/off state with his/her eyes through the movement. 
     When the power supply is desired to be turned on in a state where the connector unit  100  is inserted in the electronic product such as the notebook, the netbook or the like, if the manual control switch  295  is pushed in the A direction, the fixed contact  285  and the elastic contact  286  are connected to each other and make the state illustrated in  FIG. 5 , similarly as supplying power by pressing the knob  219 . As described above, it is possible to manually supply power through the manual control switch  295 . 
     Meanwhile, as illustrated in  FIG. 7 , when the connector unit  100  is extracted from the connection terminal of the electronic product such as the notebook, the netbook or the like, the knob  219  returns to an original position as the knob spring  281  moves in the C direction. At this time, the cam lever  282  moves in the C direction as opposed to a case where the knob  219  is pressed in the D direction, and makes the state illustrated in  FIG. 3  without touching the cam  294 . 
     At this time, since the supply current becomes equal to or smaller than the reference current i 1  when the product is separated, the micom applies the voltage to one direction of the solenoid coil  284  and thus the repulsive force with the magnet  288  is generated so that the slide  293  pulls the cam  294  in the B direction by the cam spring  292 , and the striker returns to the original position and thus the fixed contact  285  and the elastic contact  286  are separated from each other. As a result, the input power is cut off and then the standby power is interrupted. 
       FIG. 2  is an internal circuit block diagram of the power supply apparatus with the standby power cut-off structure and a related product according to an embodiment of the present invention, and illustrates, for example, a structure of the power supply unit  200  connected to the product  300  having a battery. First describing an internal configuration of the product  300  with reference to  FIG. 2 , the product  300  such as the notebook, the netbook or the like, for example, includes a main board (main B/D) for processing and controlling information, a key board (key B/D) for inputting data, a display unit for a screen display, a battery used as a power source when carrying the product, a battery charger for controlling charging of the battery, a DC/DC converter for converting DC power supplied from the power supply apparatus or battery power to power required by the corresponding product, a power switch (P/SW) for turning “on” or “off” a power supply, a power controller for controlling power according to an “on” or “off” state of the power switch, a standby power unit  302  for supplying power to control the power when the power supply is turned “off”, the standby power unit  302  and a switcher  303  therein for supplying power to the DC/DC converter when a power “on” signal is detected, and a Wake-on-LAN  305  for driving the product  300  through an Internet from the outside in a state where the power supply is turned “off”. 
     In such a configuration, particularly according to characteristics of the present invention, the product  300  may further include a switching unit driving switcher  301  for supplying power in order to allow the power supply apparatus to operate when the power supply is turned “on” in a state where the power from the power supply apparatus is cut off. The switcher  301  may be configured by a switching transistor Q 6  for providing battery power to the power supply terminal of the connector unit of the power supply apparatus under a control of the power controller. 
     Meanwhile, when the corresponding product, for example, a radio or a CD player does not have a charging battery, a configuration in which power is supplied to the power supply apparatus from the corresponding product is not provided, so that an existing product can be directly used. 
     Describing the configuration of the power supply apparatus with reference to  FIG. 2 , the power supply apparatus may include the connector unit  100  and the power supply unit  200 , and the connector unit  100  may include the switching unit  280  having the configuration illustrated in  FIGS. 1 ,  3 , and  7 . In addition, the power supply unit  200  includes a plug  202  for receiving external power (AC 110/220V), a power unit  200  for converting power provided from the corresponding plug  202  (via the switching unit  280 ) to DC power suitable for the product  300  and generating its own operation power VCC, a current sensing unit  204  for identifying a supply state of the power provided via the switching unit  280 , a controller (including a micom U 2  and a memory U 1 ) for receiving a current value from the current sensing unit  204  to grasp the supply state of current power, outputting a control signal for a standby power cut-off when it is determined that a battery of the currently connected product is fully charged and/or a power supply of the product is turned off, and determining that the current product is switched to an on state from an off state to output a control signal for a power supply, and a driver  201  for generating a switching driving signal to the switching unit  280  according to the control signal output from the controller. The micom U 2  included in the controller performs operation and determination actions, and the memory U 1  performs a function of storing a value of a current flowing when the power supply of the product is turned off and the battery is fully charged (when the power supply of the product with no battery is in the off state) as a reference current value. 
     At this time, the driver  201  may further include a constant voltage apparatus Q 7  for receiving the power through the switching unit driving switcher  301  to generate operation power of the controller and supplying the generated operation power when a power switch of the product  300  with the battery is turned “on” in a state where power of the power supply apparatus is cut off. 
     Further, the driver may be implemented in a structure connecting a first switching element to a fourth switching element (for example, npn type transistors Q 1 , Q 2 , Q 3 , and Q 4 ) as a means for driving the switching unit  280  by the control signal of the controller (micom U 2 ). 
     At this time, the first and second switching elements (transistors) Q 1  and Q 2  receive an input (for example, collector terminal) of power commonly provided from the constant voltage apparatus Q 7  and their own operation power VCC, and an output (for example, emitter terminal) of the second switching element Q 2  is connected to a first terminal of the solenoid and an output (emitter terminal) of the first switching element Q 1  is connected to a second terminal of the solenoid. Further, an input (collector terminal) of the third switching element Q 3  is connected to the first terminal of the solenoid and an output (emitter terminal) is connected to a ground terminal, and an input (collector terminal) of the fourth switching element Q 4  is connected to the second terminal of the solenoid and an output (emitter terminal) is connected to the ground terminal. 
     Describing an operation of the power supply apparatus having the configuration as illustrated in  FIG. 2  according to the present invention, when the power supply apparatus is inserted in an outlet and the connector unit  100  of the power supply apparatus is connected to the product  300 , the knob  219  of the switching unit  280  moves in the D direction and the operation of the switching unit  280  as described above is executed, which makes the state illustrated in  FIG. 5 . Then, the fixed contact  285  and the elastic contact  286  of the switching unit  280  are connected to each other and power is applied to the power unit  203 . As a result, the power unit  203  generates and supplies power required by the power supply apparatus and power required by the product  300 . 
     When the required power is supplied, the micom U 2  reads the current value from the current sensing unit  204  by an analog/digital converter AD 1 , stores the current value in an internal buffer, continuously checks a current flowing in the product  300  to compare the checked current with the value in the buffer, and changes the current into the value in the buffer when the current is smaller than the value in the buffer. Since the current value has no change when the power supply of the product  300  is turned “off” and the battery power is fully charged, if there is no change in the current although the current is additionally measured for a preset time T, it is considered that the power supply is turned “off” and the battery power is fully charged, and thus the current value in the buffer as the reference current i 1  is stored in the E2-PROM memory U 2  as a power “off” reference value. Thereafter, a second output O 2  of the micom U 2  is output as being in a “high” state in order to cut off the standby power. Accordingly, the first and third transistors Q 1  and Q 3  of the driver  201  are turned “on”, and thus a current flows from a point P to a point U via the solenoid  284 . Then, the repulsive force with the magnetic  288  is generated, and the cam  294  is pulled in the B direction by the cam spring  292 . Therefore, the striker  291  returns to the original position, and the fixed contact  285  and the elastic contact  286  are separated from each other as illustrated in  FIG. 6 , thereby cutting off the input power and then the standby power. 
     When a signal is input to a Wake-on-LAN detector  305  from the outside through an Internet or when the power switch (P/SW) of the product  300  is turned “on”, since the standby power unit  302  supplies minimally required power to the product even when the power supply is turned “off”, the power controller detects the signal or the on state, and transmits a control signal to the switcher  303  through an output O 4 . Accordingly, the required power is supplied to the product  300  through an operation of the DC/DC converter, and the product (notebook or the like) normally operates. 
     Further, the power controller transmits the control signal to the switching unit power switcher  301  through an output O 3  for the preset time t 1 , and accordingly the battery power is supplied to the micom U 2  through the constant voltage apparatus Q 7  of the driver  201  of the power supply apparatus, which starts operating the micom U 2 . The micom U 2  starts an initial operation to transmit a “high” pulse output to the first output O 1  and turns “on” the second and fourth transistors Q 2  and Q 4  of the driver. Accordingly, the current flows from the point U to the point P via the solenoid  284 , and pulling force with the magnet  288  is generated, so that the slide  293  pulls the cam  294  in the A direction, which allows the striker  291  to connect the elastic contact  286  and contact  285  as illustrated in  FIG. 5 . Accordingly, the power is supplied to the power supply apparatus, and the power supply apparatus supplies the required power to the product  300 . 
     Meanwhile, describing an operation of the power supply apparatus when the power supply apparatus is connected to the product having no battery, similarly as a case of the product having the battery, the power supply apparatus is inserted in the connector unit  100 , the knob  219  of the switching unit  280  moves in the D direction and the operation of the switching unit  280  as described above is executed, which makes the state illustrated in  FIG. 5 . Then, the fixed contact  285  and the elastic contact  286  of the switching unit  280  are connected to each other, and thus power is applied to the power unit  203 , thereby the power unit  203  generates and supplies power required by the power supply apparatus and power required by the product  300 . 
     When the required power is supplied, the micom U 2  reads the current value from the current sensing unit  204  by an analog/digital converter AD 1 , stores the current value in an internal buffer, continuously checks a current flowing in the product  300  to compare the checked current with the value in the buffer, and changes the current into the value in the buffer when the current is smaller than the value in the buffer. Since the current value has no change when the power supply of the product  300  is turned “off” and the battery power is fully charged, if there is no change in the current although the current is additionally measured for a preset time T, it is considered that the power supply is turned “off”, and thus the current value in the buffer as the reference current i 1  is stored in the E2-PROM memory U 2  as a power “off” reference value. Thereafter, a second output O 2  of the micom U 2  is output as being in a “high” state in order to cut off the standby power. Accordingly, the first and third transistors Q 1  and Q 3  of the driver  201  are turned “on”, and thus a current flows from a point P to a point U via the solenoid  284 . Then, the repulsive force with the magnet  288  is generated, and the cam  294  is pulled in the B direction by the cam spring  292 . Therefore, the striker  291  returns to the original position, and the fixed contact  285  and the elastic contact  286  are separated from each other as illustrated in  FIG. 6 , thereby cutting off the input power and then the standby power. 
     At this time, in the product having no battery, in order to turn “on” the power supply of the product without separating the connector unit  100 , the fixed contact  285  and the elastic contact  286  are connected to each other by pushing the manual control switch  295  of the switching unit  280  in the A direction as illustrated in  FIG. 5 . Accordingly, the power is supplied to the power supply apparatus, and the power supply apparatus supplies the required power to the product, which allows the product to normally operate when the power supply of the product is turned “on” in the future. 
     In such an operation, the product having no battery may have a configuration performing only a power cut-off operation without including the memory U 2  since it is considered that the power supply is turned “off” when there is no change in the current although the current is additionally measured for a predetermined time T. 
     Meanwhile, in the above detailed description, the power supply apparatus such as the notebook or the radio are described as an example in an embodiment for easier understanding of the present invention, but it will be apparent to those skilled in the art that the same principle may be applied to other similar products in the present invention. 
     Accordingly, various modifications and changes may be made to respective components without departing from the sprit and the scope of the present invention. The scope of the present invention is not limited to the above described embodiments, but should be defined by the appended claims.