Abstract:
A universal power adapter has an input for receiving an input voltage from a power source and an output for supplying an output voltage selected from amongst two or more preset voltages. A voltage converter circuit converts between the input voltage and the two or more preset voltages. A connector tip connectable with the output connects one of the two or more preset voltages to the output

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to power adapters/converters used to power or charge portable electronic equipment. More particularly, although not exclusively, the invention relates to a universal battery charger and/or power adapter having a choice of configurations for use in different countries and with different equipment. 
       BACKGROUND  
       [0002]    The applicant has already proposed an electrical adapter for use in countries having main electrical pin/socket patterns that allow no alternative plug-insertion orientations. This adapter is described in the following published documents, the entire contents of which are incorporated herein by reference: 
         [0003]    Australian Patent Application No. 2006202331 filed on 31 May 2006, 
         [0004]    Chinese Patent Application No. 200610114891.9 filed on 16 Aug. 2006, 
         [0005]    Chinese publication CN1518169A dated August 2004. 
         [0006]    European Community Patent Application No. 06252004.4 filed on 11 Apr. 2006, 
         [0007]    European publication EP1437804A2 dated 14 Jul. 2004, 
         [0008]    Japanese Patent Application No. 2006-236097 filed on 31 Aug. 2006, 
         [0009]    Japanese publication 2004214206A2 dated 29 Jul. 2004, and 
         [0010]    Korean Patent Application No. 10-2006-0048801 filed on 30 May 2006. 
         [0011]    Taiwanese Patent Application No. 95119620 filed on 2 Jun. 2006, 
         [0012]    U.S. Pat. No. 6,942,508 dated 13 Sep. 2005, 
         [0013]    U.S. patent application Ser. No. 11/401,443 filed on 11 Apr. 2006, 
         [0014]    The electrical adapter disclosed in the above documents has a plug top that can be changed to match the different power outlet socket configurations in use in different countries. The pug top and a matching receptor on the electrical adapter have cooperating rotary connection features with electrical connections to facilitate connection of a desired pug top to the adapter. The electrical adapter can also be used with various different pieces of electrical equipment. The electrical adapter has multiple output leads having different voltage outputs or a single lead with a selector switch to set the output voltage of the lead. This requires the user to make a selection of output leads or to set a selector switch. If a wrong selection is made the electrical equipment being used with the adapter might not work, or worse, might be damaged. 
       SUMMARY OF THE INVENTION  
       [0015]    It is one object of the current invention to provide a power adapter/converter for portable electronic equipment which overcomes or at least ameliorates this problem, or which at least provides the public with a useful choice. A preferred embodiment of the present invention provides an electrical adapter which does not require user selection of output voltage. 
         [0016]    Accordingly, there is disclosed herein a universal power adapter for converting between an input voltage and two or more output voltages, comprising an input for receiving an input voltage from a power source, an output for supplying an output voltage selected from amongst two or more preset voltages, a voltage converter circuit for converting between the input voltage and the two or more preset voltages, and a connector tip connectable with the output for facilitating connection of a power consuming device to the output, the connector tip further connecting one of the two or more preset voltages to the output. 
         [0017]    Preferably, the voltage converter includes a voltage divider circuit having floating divider legs, and the connector tip grounds one or more of said floating legs to connect one of the preset voltages to the output. 
         [0018]    Preferably, the output includes a plurality of terminals connected with respective ones of the floating divider legs, and the connector tip includes a one or more pins that engage respective terminals when the tip is connected with the output. 
         [0019]    Preferably, the universal power adapter is a direct current converter, the input being adapted for connection with a direct current voltage source. 
         [0020]    Preferably, the input includes rotary connection features for connection of interchangeable plug bases for use in power outlets of different countries. 
         [0021]    Preferably, the universal power adapter further includes a power converter having an input connectable with an alternating current power supply and an output connectable with the input for supplying the input voltage to the voltage converter. 
         [0022]    Preferably, the universal power adapter further includes two or more interchangeable connector tips for connect different ones of the two or more preset voltages to the output. 
         [0023]    There is also disclosed herein universal power adapter/converter comprising an adapter body having an input connector and an output connector, a power converter circuit having an input connected with the input connector and an output connected with the output connector, a control circuit having two or more preset output voltages, the control circuit connected with the input connector and output connector, and one or more adapter tips connectable with the input connector or output connector and thereby connecting one of the preset voltages of the power converter circuit. 
         [0024]    Further aspects of the present invention will become apparent from the following description which is given by way of example only. 
     
    
     
       BRIEF DESCRIPTION OF DRAWING FIGURES  
         [0025]    Preferred embodiments of the current invention will now be described with reference to the accompanying drawings, wherein: 
           [0026]      FIG. 1  is a schematic electrical circuit diagram of a power adapter/converter according to the invention, 
           [0027]      FIG. 2  is a schematic illustration of the power adapter/converter, 
           [0028]      FIG. 3  is a schematic illustration of an output connector of the power adapter/converter, 
           [0029]      FIG. 4 , is a schematic illustration of adaptor tip of the power adapter/converter, and 
           [0030]      FIG. 5  is a schematic illustration of an alternative embodiment of the adaptor tip and converter output. 
       
    
    
     DETAILED DESCRIPTION  
       [0031]    The invention will now be described as practiced in a universal charger and power adapter for use in different countries and with various type of portable electronic equipment. The power adapter has interchangeable plug bases for use in power outlets of different countries. The power adapted has three power outputs at the remote end of three output cords for connection of interchangeable adapter tips that fit different types of electronic equipment. Two outputs have a fixed 5.5V output with mini-USB connectors for charging or powering equipment that can normally be charged/powered from a computer USB port, such as mobile phones, PDA&#39;s, handheld computers and audio (MP3) players. The third outlet has a variable voltage output for powering/charging laptop computers and the like. The adapter has a selectable voltage setting for choosing the voltage output of the third output. At the end of the third output chord is a mating socket to which interchangeable adapter tips are connected for use with higher power equipment such as laptop computers and the like. 
         [0032]    Referring to the drawings of the current invention, in a preferred embodiment a power converter  1  can be connected to the mating socket of the third adapter output. The converter  1  has a DC power input side  2  with an input connector for mating with the output mating socket of the adapter., and an output side  3  with an output connector having ground and a voltage terminals (V 1 ) and four voltage setting terminals P 11 , P 12 , P 13  and P 14 . As with the electrical adapter, different adapter tips  4 ,  5 ,  6  can be connected to the output connector  3  of the power converter  1  for connection of the converter to different types of electrical equipment. 
         [0033]    Within the power converter  1  is electric circuitry including feedback and pulse width modulation (PWM) controller operating power switches Q 1  and Q 2  of the power converter circuit  7 . Inductor L 1  and capacitor C 1  are provided for output voltage and current smoothing as is known in the art. The PWM controller has a plurality of preset output voltages and controls the timing and duty cycle of switches Q 1  and Q 2  in accordance with a feedback signal at input V FB . A feedback circuit  8  comprising voltage divider resistors R 1 , R 2 , R 11 , R 12 , R 13  and R 14 , having output connector terminals P 11 , P 12 , P 13  or P 14 , providing a feedback signal to terminal V FB  of the PWM controller. The output connector terminals P 11 , P 12 , P 13  or P 14  of the voltage divider circuit are normally floating. The ratio of the output voltage to feedback signal is controlled by grounding one or more of the output connector terminals P 11 , P 12 , P 13  or P 14  to adjust the ratio of the voltage divider circuit. When the ration of the feedback signal is changed the PWM controller sees this as a change in output voltage and responds by rising, or lowering, the output voltage accordingly. 
         [0034]    Converter  1  is a power supply with one or more than one preset output voltage. In the preferred embodiment the grounding of terminals P 11 -P 14  is via connections inside the adapter tips  4 ,  5 ,  6 . With  4  setter terminals P 11 -P 14  a configuration of sixteen different output voltages are available. When a user connects one of the adapter tips a respective preset output voltage appears at the adapter tip. Each adapter tip  4 ,  5 ,  6  is configured for connection with certain electronic equipment and has appropriate ones of its pins P 1 , P 2 , P 3 , P 4  grounded within the adapter tip so that when connecting the adapter tip to the output connector the correct output voltage is automatically set for the adapter tip configuration and electrical equipment it is used with. 
         [0035]    Converter  1  is a power supply with one or more than one preset output voltages, although the output voltage V 1  can be changed, it is not a programmable output power supply, in short, the output voltage cannot be set to a desired voltage by an external programmer. The converter can only provide a set of output voltage that is determined by the combination of voltage divider resistors R 1 , R 2 , R 11 , R 12 , R 13  and R 14 . 
         [0036]    A power converter of the invention gives very good protection against overloading. For example, if the converter voltage is programmable to any voltage by external means, it is very possible for the converter to operate out of the designed range, or a fault or instability of the external means can change the converter output voltage and cause damage to connected equipment. As the invention does not rely on external components or values to adjust the output voltage, only a tip is used to connect the resistors to ground, and if the tip fails or is absent, it can only cause a less than desired output voltage. 
         [0037]    It will also be appreciated by those skilled in the art that in other embodiments of the invention setter terminals could also be applied to the input connector so that a connector from the input power supply can likewise have setting terminals grounded within the connector to automatically set the input voltage of the power converter to the output voltage from the power supply. 
         [0038]    In the device of the earlier application the connectors included a locking collar  41  in that application) for locking the adapter tip to the power cords. In certain embodiments of the current invention it is envisage that the locking collar can be incorporated on the power adapter connector. This reduces the numbers of parts for interchangeable adapter tips and makes their manufacturer easier and cheaper. A single locking collar on the power adapter connector can lock multiple adapter tips to the power adapter. 
         [0039]      FIG. 5  illustrates an alternative arrangement for the converter output  3  and adaptor tips  4 ,  5 ,  6 . In the alternative embodiment there is no grounding or electrical connection to the adaptor tip setting pins P 1 , P 2 , P 3 , P 4 . The output connector  3  of the power converter has a plurality of connector jacks S 11 , S 12 , S 13 , S 14  that can receive a corresponding adaptor tip pin P 1 , P 2 , P 3 , P 4  and thereby make an electrical connection within the power converter. The floating leg of each divider resistor R 11 , R 12 , R 13 , R 14  is connected with a corresponding connector jack S 11 , S 12 , S 13 , S 14 . If a connector jack S 11 , S 12 , S 13 , S 14  receives a pin P 1 , P 2 , P 3 , P 4  of the adaptor tip the corresponding resistor leg is grounded. By provided different combinations of pins P 1 , P 2 , P 3 , P 4  on adaptor tips different ones of the resistors can be grounded by connection of an adaptor tip  4 ,  5 ,  6  to the output connector  3  thereby connecting one of the preset output voltages to the adaptor tip. 
         [0040]    It should be appreciated that modifications and alternations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention.