Abstract:
A mobile device and a power supply device are provided in which a first part of a connector detachably connects an electrical device to the mobile device, a second part of the connector matches the first part, and a converter generates electrical energy by converting energy of a mechanical movement into electrical energy, where the electrical energy is generated by relative mechanical movement occurring between first and second parts of the connector when the first and second parts are connected.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a divisional of copending application U.S. Ser. No. 12/496,756 filed on Jul. 2, 2009. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method and a circuit for energizing an electrical device, as well as a system, a mobile device, and a power supply device using the method and the circuit for energizing an electrical device. 
     BRIEF SUMMARY OF THE INVENTION 
     According to an embodiment of the present invention, a method for energizing an electrical device is provided. The electrical device is coupled via a switch to an electrical power supply. According to the method, electrical energy is generated by converting energy of a mechanical movement into electrical energy. The generated electrical energy is supplied to the switch to provide an electrical coupling of the electrical device to the electrical power supply. The switch may be a semiconductor switch, for example a thyristor, a MOSFET, an IGBT or the like, or a mechanical switch, for example a relais. The electrical device may be a charger for charging a further electrical device, for example a battery powered mobile device. The charger and the battery powered device may be detachably connectable with each other via a plug and a matching socket. In this case, the electrical energy for activating the switch may be generated by the mechanical movement of inserting the plug into the socket. Furthermore, the electrical device may be a power supply unit for supplying the further device with electrical energy from the electrical power supply. 
     In the field of consumer electronics, especially battery powered mobile devices like for example mobile phones, mobile personal digital assistants, mobile audio playback devices like MP3 players, and mobile computers, the mobile device is coupled to the electrical power supply via a charger or a power supply unit. The charger or the power supply unit is on one side detachably connected to the battery powered mobile device via a connector comprising a plug and a matching socket, and on the other side via another connector to the electrical power supply, the so-called mains. Many users of such consumer electronics leave the charger or power supply unit connected to the electrical power supply, when they disconnect the mobile battery powered device from the charger or power supply unit. However, even when the connection between the mobile or battery powered device to the charger or power supply unit is disconnected, the charger or the power supply unit still consume electrical energy from the electrical power supply as long as it is are electrically connected to the electrical power supply. 
     Therefore, according to an embodiment of the present invention, the charger or the power supply unit is coupled to the electrical power supply via a switch which is adapted to couple and decouple the charger or the power supply unit electrically to/from the electrical power supply. A decoupling may be initiated by sensing a disconnecting of the mobile battery powered device from the charger or the power supply unit. For initiating an initial coupling of the charger or the power supply unit to the electrical power supply, the switch has to be activated, thus energizing the charger or the power supply unit with electrical energy from the electrical power supply. Therefore, according to an embodiment of the present invention, electrical energy is generated by converting a mechanical movement into electrical energy, and this electrical energy is provided to the switch. After the charger or the power supply unit has been energized, the switch may then be held in the activated state with electrical energy being derived from the charger or the power supply unit from the electrical power supply. Thus, the charger or the power supply unit consumes electrical energy only when the mobile battery powered device is connected. 
     According to an embodiment of the present invention, a piezoelectric element is used for generating electric energy from a mechanical movement by using the piezoelectric effect. Possible materials for the piezoelectric element include piezoelectric plastics and piezoelectric ceramics, for example. Therefore, the piezoelectric element may be integrated into a connector connecting the electrical device like the charger or the power supply unit to the further electrical device like the mobile battery powered device. Thus, when connecting the electrical device with the further device by moving the plug into the matching socket, the piezoelectric element may be mechanically activated to generate the electrical energy being supplied to the switch. 
     According to another embodiment, the generated electrical energy is galvanically isolated from the switch. This helps to separate lower voltages on a secondary side of the electrical device from higher voltages of a primary side of electrical device, to keep hazardous voltages away from the user. 
     According to another embodiment, the generated electrical energy is stored before being supplied to the switch. When using for example a piezoelectric element for generating the electrical energy, the piezoelectric element may generate a short peak of high energetic electrical energy. This peak may be too short for energizing the electrical device long enough to get the electrical device started up, and therefore it may be advantageous to store this electrical energy for example in a capacitor intermediately and provide it for a longer time from the capacitor to the switch until the electrical device is started up. Furthermore, the generated electrical energy may be limited to a predefined range, to avoid voltage peaks which may be dangerous for the electrical device, the further electrical device or user. 
     According to another embodiment of the present invention a circuit for energizing an electrical device is provided. The circuit comprises a switch, a converter, and a control circuit. The switch is adapted to couple the electrical device to an electrical power supply. The converter is adapted to generate electrical energy by converting energy of a mechanical movement into electrical energy. The control circuit is coupled to the switch and the converter and is furthermore adapted to supply the generated electrical energy from the converter to the switch, wherein the switch upon receiving the generated electrical energy provides an electrical coupling of the electrical device to the electrical power supply. The converter for generating electrical energy from a mechanical movement may be a piezoelectric element utilizing the piezoelectric effect for generating the electrical energy from the mechanical movement. The electrical device may comprise a charger for charging a further device or a power supply unit for supplying the further device with electrical energy from the electrical power supply. The electrical device may be detachably connectable to the further device via a connector comprising a plug and a matching socket. The converter, for example the piezoelectric element, may be integrated into the connector such that the generated electrical energy is generated by the mechanical movement when the plug is inserted into the socket. 
     The further device may comprise a battery powered device which cannot be connected directly to the high voltage of the electrical power supply, but needs to be supplied by a lower voltage derived from the electrical power supply by the electrical device, for example the charger or the power supply unit. The battery powered device may be a mobile device, a mobile phone, a personal digital assistant, a mobile navigation system or a mobile computer. 
     According to another embodiment the control circuit is further connected to the electrical device and configured to supply electrical energy from the electrical device to the switch after the mechanically generated electrical energy was supplied to the switch. Thus, the electrical coupling of the electrical device to the electrical power supply is maintained even when after the mechanical movement the converter does not provide further electrical energy to the switch. 
     According to another embodiment, the control circuit comprises a transformer for galvanically isolating the electrical energy generated by the converter from the switch. Furthermore, the control circuit may comprise a capacitor for storing the generated electrical energy before it is supplied to the switch. Finally, the control circuit may comprise a voltage limiting arrangement like a Zener diode, a breakdown diode, a low pass filter or a voltage regulator etc. for limiting the voltage of the electrical energy generated by the converter to a predefined range. 
     According to another embodiment of the present invention a system comprising a first electrical device, a second electrical device, a switch, a connector, a converter and a control circuit is provided. The first electrical device, for example a charger or a power supply unit, is configured to adapt electrical energy from an electrical power supply, a so-called mains, to electrical requirements of the second electrical device, for example a mobile device, a battery powered device, a mobile phone, a personal digital assistant, a mobile navigation system or a mobile computer. The switch is adapted to couple the first electrical device to the electrical power supply and may comprise a thyristor, a MOSFET or an IGBT. The connector is adapted to detachably connect the first electrical device to the second electrical device. The connector comprises a plug and a matching socket. According to a preferred embodiment, the connector is a USB connector. The converter is adapted to generate electrical energy by converting a mechanical movement into electrical energy. The converter is integrated into the connector such that the generated electrical energy is generated by a mechanical movement of the plug being inserted into the socket. The control circuit is coupled to the switch and the converter. The control circuit is adapted to supply the generated electrical energy from the converter to the switch to enable the switch to provide an electrical coupling of the first electrical device to the electrical power supply. 
     The system may further comprise an energy supply line for supplying energy from the first electrical device to the second electrical device. The energy supply line may be a multiple-conductor line or cable which is on one end of the line fixedly connected to the first electrical device and provides for example a plug on the other end, wherein the plug is matching to a socket provided in the second electrical device. The generated electrical energy, which may be generated by moving the plug into the socket, is transmitted from the converter to the control circuit via the energy supply line. 
     According to another embodiment of the present invention a mobile device is provided which comprises a first part of a connector for detachably connecting an electrical device, for example a charger or a power supply unit, to the mobile device. The electrical device comprises a second part of the connector which is matching to the first part comprised in the mobile device. The mobile device comprises furthermore a converter adapted to generate electrical energy by converting energy of a mechanical movement into electrical energy. The converter is integrated into the first part of the connector such that the generated electrical energy is generated by the mechanical movement which occurs when the first part of the connector is connected to the second part of the connector, for example when the first part is inserted into the second part or vice versa. 
     The mobile device may be a battery powered device, for example a mobile phone, a personal digital assistant, a mobile navigation system or a mobile computer. 
     According to yet another embodiment of the present invention, a power supply device is provided. The power supply device comprises a power converter, a switch, a first part of a connector, a converter, and a control circuit coupled to the switch and the converter. The power converter is adapted to convert electrical energy from an electrical power supply, a so-called mains, to electrical requirements of a further electrical device which is connectable to the first part of the connector. In general, this conversion comprises a conversion of electrical energy with a high voltage, for example 110 V or 220 V, to electrical energy with a lower voltage, typically in the range of 5-25 V. However, a power converter is not restricted to such a downscaling of the voltage and may also provide an upscaling of the voltage, for example to convert 12 V from an electrical power supply of a vehicle to the electrical requirements of the further electrical device. The switch is adapted to couple the power converter to the electrical power supply and may comprise a semiconductor switch, for example a thyristor, a triac, a MOSFET, or an IGBT. The first part of the connector may be a plug or a socket for detachably connecting the power supplied device to the further electrical device, wherein the further electrical device comprises a second part of the connector, for example a socket or a plug matching to the first part. The converter is adapted to generate electrical energy by converting energy of a mechanical movement into electrical energy. The converter is integrated into the connector such that the generated electrical energy is generated by the mechanical movement when the first part of the connector and the second part of the connector are connected. The control circuit as adapted to supply the electrical energy generated from the converter to the switch to provide an electrical coupling of the power converter to the electrical power supply. 
     The power supply device may be a charger for charging the further electrical device. The converter for generating the generated electrical energy from the mechanical movement may be integrated in the first part of the connector or may be alternatively integrated in the second part of the connector. 
     Although specific features described in the above summary and the following detailed description are described in connection with specific embodiments, it is to be understood that the features of the embodiments described can be combined with each other, unless it is noted otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Hereinafter exemplary embodiments of the invention will be described with reference to the drawings. 
         FIG. 1  shows a block diagram of a system according to an embodiment of the present invention. 
         FIG. 2  shows an embodiment of a switch according to an embodiment of the present invention in more detail. 
         FIG. 3  shows an embodiment of a control circuit according to an embodiment of the present invention. 
         FIG. 4  shows another embodiment of a system according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, exemplary embodiments of the present invention will be described in detail. It is to be understood that the following description is given only for the purpose of illustrating the principles of the invention and it is not to be taken in a limiting sense. Rather, the scope of the invention is defined only by the appended claims and is not intended to be limited by the exemplary embodiments hereinafter. 
     It is to be understood that in the following detailed description of the exemplary embodiments, any direct connection or coupling between functional blocks, devices, components or other physical or functional units shown in the drawings or description herein could also be implemented by an indirect connection or coupling. The use of same reference numbers in different instances in the description and the figures may indicate similar or identical items. 
     It is further to be understood that the features of the various exemplary embodiments described herein may be combined with each other unless specifically noted otherwise. 
       FIG. 1  shows an embodiment of a system  100  according to the present invention. The system  100  comprises a charger  101  and a mobile device  102 , for example a mobile phone. The charger  101  comprises a primary switched battery charger  103 , a control circuit  104 , a two-way semiconductor switch  106 , a current sensing resistor  107  and a charging connector  108 . The primary switched battery charger  103  is connectable via lines  109  and  110  to an electrical power supply, a so-called mains, providing for example 110 V or 220 V. 
     In the line  110  the semiconductor switch  106  is inserted such that, when the switch  106  is in the disconnected state, the primary switched battery charger  103  is electrically completely disconnected from the electrical power supply and no current is flowing through lines  109  and  110 . When the semiconductor switch  106  is in the connected state, the primary switched battery charger  103  is connected to and supplied with energy from the electrical power supply via lines  109  and  110 . 
     The primary switched battery charger  103  is adapted to convert a high voltage supplied from the electrical power supply into a low voltage which is suitable for charging a battery of the mobile device  102 . When the primary switched battery charger  103  is connected on its primary side via lines  109  and  110  to the electrical power supply, the primary switched battery charger  103  provides on its secondary side via lines  111  and  112  the lower voltage. The lines  111  and  112  connect the secondary side of the primary switched battery charger  103  with the charging connector  108 . The charging connector  108  may be a plug which fits into a corresponding socket in the mobile device  102 . 
     As shown in  FIG. 1 , in line  112  a series resistor R  107  is inserted which is used as a current sensing resistor which provides a current sensing voltage on lines  113  and  114  as long as a current is flowing through line  112  and the resistor  107 . Therefore, when the mobile device  102  is connected via the charging connector  108  to the primary switched battery charger  103 , and the primary switched battery charger  103  is connected via lines  109  and  110  to the electrical power supply, a charging voltage will be present on lines  111  and  112  and a corresponding charging current will flow through lines  111  and  112  causing a hold voltage on lines  113  and  114 . 
     The charging voltage on lines  111  and  112  is additionally supplied via lines  115  and  113 , respectively, to the control circuit  104 , and additionally the hold voltage on lines  113  and  114  is supplied to the control circuit  104 . As long as the charging voltage and the hold voltage are present, the control circuit  104  activates the semiconductor switch  106  via a connection  116  between the control circuit  104  and the semiconductor switch  106  to keep the semiconductor switch  106  in the connected state. When the charging connector  108  is removed from the mobile device  102 , i.e. the plug of the charging detector  108  is pulled out of the socket of the mobile device  102 , the current flow through the lines  111  and  112  is stopped. Thus, the hold voltage on the lines  113  and  114  becomes zero and the control circuit  104  causes the semiconductor switch  106  via the connection  116  to change into the disconnected state. Because of this there is no current flow through the lines  109  and  110  from the electrical power supply to the battery charger  103  and thus the battery charger  103  does not consume any energy from the electrical power supply anymore. 
     However, when the charging connector  108  is reconnected to the mobile device  102 , the charger  101  has to be reenergized to provide the charging voltage for the mobile device  102 . This is accomplished by generating electrical energy by converting mechanical energy into electrical energy. The mechanical energy is induced by the insertion of the charging connector  108  into the socket of the mobile device  102 , as indicated by a force arrow F in  FIG. 1 . To accomplish this, the charging connector  108  comprises a piezoelectric element  117  and a spring suspended hammer  118 . The piezoelectric element  117  is for example a piezoelectric ceramic or a piezoelectric plastic. The piezoelectric element  117  works in a similar way as a piezoelectric gas lighter, but using much lower force and much lower voltage. The spring suspended hammer  118  is released when the charging connector  108  is plugged into the mobile device  102 . The hammer  118  hits the piezoelectric element  117  thus generating a transient voltage as a starting voltage on lines  119  and  120 . When the charging connector plug  108  is unplugged from the mobile device socket  102 , the spring of the spring suspended hammer  118  is returned to its initial state. 
     Thus, the piezoelectric element  117  is excited by an impact from the spring suspended hammer mechanism  118 , and the transient starting voltage is provided to the control circuit  104 . This starting voltage is fed from the control circuit  104  via the connection  116  to the semiconductor switch  106 . The energy needed to trigger the semiconductor switch  106  is low and the energy provided by the piezoelectric element  117  is sufficient to energize the semiconductor switch  106  for such a long time that the primary switched battery charger  103  gets started up and provides the charging voltage to the mobile device  102  and thus the hold voltage on lines  113  and  114  for keeping the switch  106  via the control circuit  104  in the conducting state even when there is no more energy from the piezoelectric element  117 . 
     The two way semiconductor switch  106  may be composed of a triac as indicated in  FIG. 1  or may be composed of two MOSFETs in series as indicated in  FIG. 2 , or may be composed of IGBTs in series (not shown) or of any other suitable kind of semiconductor switch. 
     If there is a demand of a galvanic isolation, a transformer  122  can be used for coupling the transient voltage from the piezoelectric element  117 , as indicated in  FIG. 3 . The transient voltage or starting voltage from the piezoelectric element  117  ( FIG. 1 ) is supplied to a first winding  123  of the transformer  122 . This starting voltage induces in a second winding  124  of the transformer  122  a voltage which is intermediately stored in a capacitor  121  and provided via the connection  116  to a gate or control input of the semiconductor switch  106 . The capacitor  121  is optional. The capacitor  121  increases the time the starting voltage is supplied to the semiconductor switch  106  when the lengths of the transient voltage of the starting voltage is too short to start up the primary switched battery charger  103 . As indicated in  FIG. 3 , also the hold voltage on lines  113  and  114  can be galvanically isolated from the primary side of the primary switched battery charger  103 . The hold voltage provided on lines  113  and  114  is converted by a voltage to frequency converter  126  into an alternating current (AC). This alternating current is supplied to a third winding  125  of the transformer  122  and induces a hold voltage in the second winding  124  of the transformer  122 . This hold voltage is provided to the semiconductor switch  106  via the connection  116  as indicated in  FIG. 1 . 
       FIG. 4  shows another embodiment of a system  100  comprising a charger  101  and a mobile phone  102 . Similar reference signs in  FIGS. 1 and 4  indicate similar components and a detailed description of the components already described in connection with  FIG. 1  is therefore omitted. 
     The connection between the charger and the mobile phone  102  in  FIG. 4  is accomplished by a so-called USB connector  108 , and, as this USB connector  108  is a standardized component, in this embodiment the piezoelectric element  117  and the spring suspended hammer mechanism  118  are not integrated into the USB connector  108 , but integrated into the mobile phone  102 . As the standardized USB connector does not provide additional ports and lines for transmitting the starting voltage, for example lines  119  and  120  of  FIG. 1 , the transient voltage from the piezoelectric element  117  is overlaid on voltage lines  111  and  112  which are used for charging the battery of the mobile phone  102 . As indicated in  FIG. 4 , the feeding point from the piezoelectric element  117  can be equipped with a transient protection like a Zener diode  127  or a low pass filter (not shown) making sure that a too high voltage is not output on the lines  111  and  112 . 
     As stated above, the piezoelectric element  117  and the spring suspended hammer mechanism  118  are integrated into the mobile phone  102 . The spring suspended hammer is released when the USB connector  108  is inserted into the mobile phone  102  providing a force F on the hammer. The hammer hits the piezoelectric element  117  and causes the piezoelectric element  117  to generate a transient voltage which is supplied via the lines  111  and  112  to the first winding  123  of the transformer  122 . The transient voltage from the piezoelectric element  117  induces in the second winding  124  of the transformer  122  a starting voltage which is supplied via the connection  116  to the semiconductor switch  106 , as indicated in  FIG. 1 . When the connector  108  is unplugged from the mobile phone  102  the spring of the spring suspended hammer mechanism  118  is returned to its initial state. As the piezoelectric material of the piezoelectric element  117  is purely capacitive (e.g. in the range of 100 pF to 1 nF) this will not affect the normal voltage provided on lines  111  and  112  for charging the battery of the mobile phone  102 . To protect the primary switched battery charger  103  from the transient voltage of the piezoelectric element  117  a diode  128  may be coupled in series to line  111 . 
     To sum up, when the piezoelectric element  117  is excited by an impact F from the mechanism  118 , a voltage transient is generated as a starting voltage. This starting voltage is fed to the semiconductor switch  106 . Therefore, no extra voltage for triggering the semiconductor switch  106  is needed. Once the switch  106  is triggered, the switch  106  will conduct and the primary switched charger  103  will start and supply voltage to the mobile device or mobile phone  102 . As long as current is flowing to the mobile device or mobile phone  102  the hold voltage will ensure that the semiconductor switch  106  will be in the conducting state. When the mobile device or mobile phone  102  is decoupled from the charger  101 , the hold voltage will break down and the switch  106  will be in a non-conductive state. In this state no current or leak current exists and therefore the charger  101  does not consume any energy in this state. 
     While exemplary embodiments have been described above, various modifications may be implemented in other embodiments. For example, the semiconductor switch  106  may be supplied directly from the piezoelectric element  117 , without using the transformer  122 . Furthermore, for example, the hold voltage may be derived in a different manner from the primary switch battery charger  103 . 
     Furthermore, the embodiments described above may not only be used in a mobile phone, but may be used in any other kind of mobile device or battery powered device being supplied by a separate battery charger or a separate power supply unit which is connected to the device via a connector. It is also understood that all the embodiments described above are considered to be comprised by the present invention as it is defined by the appended claims.