Abstract:
A current control device is disclosed, which reduces a standby current of a semiconductor memory device and a turn-on current of a transistor. The current control device includes an input controller configured to combine a trigger signal and a set signal controlling a circuit operation status, and a drive unit configured to drive an output signal of the input controller, wherein the drive unit includes a current controller for selectively providing a ground voltage in response to an activation status of a pull-down driving signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The priority of Korean patent application No. 10-2011-0044207 filed on May 11, 2011, the disclosure of which is hereby incorporated in its entirety by reference, is claimed. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a current control device, and more specifically to a current control device capable of reducing a standby current of a semiconductor memory device and a turn-on current of a transistor. 
         [0003]    With the development of computing systems and information communication technology, semiconductor memory devices for storing information therein have been rapidly developed to be manufactured with lower costs and to have smaller sizes and larger capacitance. In addition, as demand for the reduction of energy consumption also increases, semiconductor devices have been developed to restrict unnecessary current consumption. 
         [0004]    Generally, a cell array of a dynamic random access memory (DRAM) device includes a plurality of cells coupled to word lines and bit lines that are interconnected in the form of a net. Each cell includes one NMOS transistor and one capacitor. 
         [0005]    Operations of a general DRAM device will hereinafter be described in detail. 
         [0006]    First, a row strobe signal (/RAS) for operating the DRAM device is activated to a low level, so that row address signals are input to a row address buffer. A row decoding operation for selecting one of word lines contained in the cell array is carried out by decoding the row address signals. 
         [0007]    In this case, the data of cells coupled to the selected word line is applied to a pair of bit lines BL and /BL composed of a bit line and its complementary bit line. A sense-amplifier (also called a sense-amp) enable signal indicating an operation start time of a sense amplifier is enabled to drive a sense-amp driving circuit of a cell block selected by the row address signals. 
         [0008]    After that, sense-amp bias potentials are transitioned to a core potential Vcore and a ground potential Vss by the sense-amp driving circuit, so that the sense amplifier is driven. If the sense amplifier starts its operation, voltages of the bit lines BL and /BL that have maintained a slight potential difference therebetween are transitioned to have a high potential difference therebetween. 
         [0009]    Thereafter, a column decoder turns on a column transfer transistor that transfers data from each bit line to data bus lines in response to column address signals, such that data stored in the pair of bit lines BL and /BL is output to the outside of the semiconductor memory device through the data bus lines DB and /DB. 
         [0010]      FIG. 1  illustrates a signal processing circuit diagram of a typical semiconductor memory device. 
         [0011]    Referring to  FIG. 1 , the signal processing circuit includes a NAND gate ND 1  and a plurality of inverters IV 1 ˜IV 4 . 
         [0012]    The NAND gate ND 1  performs a logic NAND operation on a trigger signal TRIGGER and a set signal SET and outputs the NAND operation result. The inverters IV 1 ˜IV 4  drive an output signal of the NAND gate ND 1  and output an output signal OUT. 
         [0013]    The typical semiconductor memory device may further include a variety of circuit elements, for example, a NOR gate, a transistor, etc. 
         [0014]    The typical semiconductor memory device may be implemented as a user-desired semiconductor memory device by a combination of an inverter, a NAND gate, a NOR gate, and a transistor. 
         [0015]    In the typical semiconductor memory device, an inverter, a NAND gate, a NOR gate, a tri-state gate, etc. are implemented on the basis of transistors. A multi-input circuit is constructed using a combination of an AND gate and an OR gate. 
         [0016]    For example, as can be seen from  FIG. 1 , an AND circuit composed of a two-input NAND gate, e.g., ND 1 , and a plurality of inverters, e.g. IV 1 ˜IV 4 , outputs a high-level output signal OUT when two inputs are high in level. 
         [0017]    In this case, the two input signals SET and TRIGGER may be input at the same time. However, if the set signal SET is first input to set the circuit to a set status, an output time of the output signal OUT may be determined by the trigger signal TRIGGER that is input after the set signal SET. In other words, each circuit logic has been designed to include the set signal SET and the trigger signal TRIGGER. A general circuit logic may be classified into one case in which a circuit enters an idle status upon receiving a set signal SET for setting the circuit and the other case in which the set signal SET and an idle entry signal are separated from each other. 
         [0018]    If the semiconductor memory device enters the idle status as a user-desired operation is completed or if the semiconductor memory device such as a DRAM device enters a current reduction status such as a power-down mode, some transistors contained in an inverter circuit may maintain a turn-on status, or an off-leakage current may be generated in some other transistors. 
         [0019]    The above-mentioned semiconductor memory device has been designed to unnecessarily consume the off-leakage current and/or the transistor turn-on current during the idle status and/or the power-down mode. 
         [0020]    Numerous inverters have been used in most circuits. Accordingly, the off-leakage current and the transistor turn-on current may be unnecessarily consumed in, e.g., a circuit using an inverter having a large width, a delay circuit, and a delay chain. 
       BRIEF SUMMARY OF THE INVENTION 
       [0021]    Various embodiments of the present invention are directed to providing a current control device, which may substantially obviate one or more problems due to limitations or disadvantages of the related art. 
         [0022]    Embodiments of the present invention relate to a current control device for controlling a path to a ground voltage VSS of a semiconductor memory device, such that it can reduce a standby current generated in a circuit and a turn-on current of a transistor according to whether the semiconductor memory device enters an idle status or a power down mode. 
         [0023]    In accordance with one embodiment of the present invention, a current control circuit includes an input controller configured to combine a trigger signal and a set signal, wherein the set signal controls an internal operation of a semiconductor device, and a drive unit configured to drive an output signal of the input controller in response to a pull-down signal, wherein the drive unit includes an inverter unit configured to drive the output signal of the input controller, and a current controller configured to selectively provide a ground voltage to the inverter unit in response to the pull-down driving signal. 
         [0024]    In accordance with another embodiment of the present invention, a current control circuit includes an input controller configured to combine a trigger signal, a bank active signal, and a set signal, wherein the set signal controls an internal operation of a semiconductor device; and a drive unit configured to drive an output signal of the input controller in response to a pull-down driving signal, wherein the drive unit includes, an inverter unit configured to drive the output signal of the input controller; and a current controller configured to selectively provide a ground voltage to the inverter unit in response to the pull-down driving signal. 
         [0025]    The inverter unit comprises a plurality of inverter elements serially connected in the form of an inverter chain, and wherein the semiconductor device is a memory device. 
         [0026]    The current controller may comprises a plurality of pull-down driving elements coupled between the inverter unit and a ground voltage terminal, the pull-down driving elements being selectively activated in response to the pull-down driving signal. 
         [0027]    The current control circuit may further comprise a drive signal generator configured to generate the pull-down driving signal. 
         [0028]    The drive signal generator may include a falling delay unit configured to delay a falling start time of the set signal by a predetermined time; and an output unit configured to combine an output signal of the falling delay unit and a power-down signal so as to generate the pull-down driving signal. 
         [0029]    The drive signal generator may deactivate the pull-down driving signal irrespective of activation of the output signal of the falling delay unit, when the power-down signal is activated. 
         [0030]    The current control circuit may further include a storage unit configured to latch an output signal of the drive unit for a predetermined time. 
         [0031]    The current controller may operates in response to the pull-down driving signal and prevent the ground voltage from being supplied to the inverter unit in a power-down mode. 
         [0032]    It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  illustrates a signal processing circuit diagram of a typical semiconductor memory device. 
           [0034]      FIG. 2  illustrates a circuit diagram of a current control device according to an embodiment of the present invention. 
           [0035]      FIG. 3  illustrates a detailed circuit diagram of a drive signal generator according to an embodiment of the present invention. 
           [0036]      FIG. 4  illustrates a circuit diagram of a current control device according to another embodiment of the present invention. 
           [0037]      FIG. 5  illustrates a detailed circuit diagram of a drive signal generator according to another embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0038]    Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0039]      FIG. 2  illustrates a circuit diagram of a current control device according to an embodiment of the present invention. 
         [0040]    Referring to  FIG. 2 , the current control device includes an input controller  100 , a drive unit  200 , and a storage unit R 1 . 
         [0041]    The input controller  100  includes a NAND gate ND 2 . The NAND gate ND 2  performs a NAND operation on a trigger signal TRIGGER and a set signal SET and outputs the NAND operation result. 
         [0042]    The set signal SET may be used to control driving of a circuit such as a semiconductor device. If the set signal SET is activated, a circuit receiving the set signal SET starts its internal operation. The trigger signal TRIGGER may correspond to a preparation signal for activating a sense amplifier in the semiconductor device. 
         [0043]    The drive unit  200  includes an inverter unit  210  and a current controller  220 . 
         [0044]    The inverter unit  210  includes pairs of PMOS transistors P 1 ˜P 3  and NMOS transistors N 1 ˜N 3 . In other words, the inverter unit  210  includes a plurality of inverters serially connected in the form of an inverter chain. In another embodiment, the inverter unit  210  may be composed of a plurality of delay elements connected in series to each other. 
         [0045]    The current controller  220  includes a plurality of pull-down driving elements disposed between the inverter unit  210  and a ground voltage terminal VSS. The pull-down driving elements are controlled by a pull-down driving signal SETFD. The pull-down driving elements are composed of NMOS transistors N 4 ˜N 6 . 
         [0046]    The NMOS transistors N 4 , N 5  and N 6  of the current controller  220  are coupled to the NMOS transistors N 1 , N 2 , and N 3  of the inverter unit  210 , respectively. The NMOS transistors N 4 ˜N 6  may receive the pull-down driving signal SETFD through their common gate terminal. 
         [0047]    Accordingly, the PMOS transistor P 1 , the NMOS transistor N 1 , and the NMOS transistor N 4  are serially coupled between a power-supply voltage terminal VCC and the ground voltage terminal VSS. The PMOS transistor P 1  and the NMOS transistor N 1  receive an output signal of the NAND gate ND 2  through their common gate terminal. The NMOS transistor N 4  receives the pull-down driving signal SETFD through a gate terminal. 
         [0048]    The PMOS transistor P 2 , the NMOS transistor N 2 , and the 
         [0049]    NMOS transistor N 5  are serially coupled between the power-supply voltage terminal VCC and the ground voltage terminal VSS. A common gate terminal of the PMOS transistor P 2  and the NMOS transistor N 2  is coupled to an inverter element of the previous stage, e.g., an output terminal of the inverter composed of the PMOS transistor P 1  and the NMOS transistor N 1 . The NMOS transistor N 5  receives the pull-down driving signal SETFD through a gate terminal. 
         [0050]    The PMOS transistor P 3 , the NMOS transistor N 3 , and the NMOS transistor N 6  are serially coupled between the power-supply voltage terminal VCC and the ground voltage terminal VSS. A common gate terminal of the PMOS transistor P 3  and the NMOS transistor N 3  is coupled to an inverter element of a previous stage. The NMOS transistor N 6  receives the pull-down driving signal SETFD through a gate terminal. 
         [0051]    The storage unit R 1  includes latch-type inverters IV 5  and IV 6  in which an input terminal of the inverter IV 5  is coupled to an output terminal of the inverter IV 6  and an output terminal of the inverter IV 5  is coupled to an input terminal of the inverter IV 6 . The storage unit R 1  latches an output signal of the drive unit  200  and outputs an output signal OUT. 
         [0052]      FIG. 3  illustrates a detailed circuit diagram of a drive signal generator  300  for generating the pull-down driving signal SETFD used in the current control device shown in  FIG. 2  according to an embodiment of the present invention. 
         [0053]    Referring to  FIG. 3 , the drive signal generator  300  includes a falling delay unit  310  and an output unit  330 . 
         [0054]    The falling delay unit  310  delays a falling time of the set signal SET and outputs a delayed set signal. That is, if the set signal SET is enabled to a high level, the falling delay unit  310  extends a period of the high level status by a predetermined time, such that a transition start time for the falling status is delayed by the predetermined time. 
         [0055]    The output unit  330  includes inverters IV 7  and IV 8  and a NAND gate ND 3 . The NAND gate ND 3  performs a NAND operation on an output signal of the falling delay unit  310  and an inverted power down signal output from the inverter IV 7  that inverts a power down signal PWRDN. The inverter IV 8  inverts an output signal of the NAND gate ND 3  to output the pull-down driving signal SETFD. 
         [0056]    Operations of the current control device shown in  FIG. 2  will hereinafter be described in detail with reference to  FIGS. 2 and 3 . 
         [0057]    For convenience of description and better understanding of the present invention, although an embodiment of the present invention describes a case of using the power-down signal PWRDN that is activated during a power-down mode, the scope or spirit of the present embodiment is not limited thereto, and can also be applied to another case in which a standby signal is activated during a standby mode. 
         [0058]    In a normal operation mode, not the power-down mode, the power-down signal PWRDN is deactivated to a low level. Accordingly, the inverted power down signal output from the inverter IV 7  has a high level. 
         [0059]    In addition, if a bank is selected in an active operation, the set signal SET transitions from a low level to a high level. As a result, the output signal of the NAND gate ND 3  goes to a low level, and the pull-down driving signal SETFD corresponding to the output signal of the inverter IV 8  goes to a high level. 
         [0060]    In this case, if the set signal SET goes to a high level and the trigger signal TRIGGER goes to a low level, the output signal of the NAND gate ND 2  goes to a high level so that the inverter unit  210  operates. 
         [0061]    When the pull-down driving signal SETFD goes to a high level, all the NMOS transistors N 4 ˜N 6  of the current controller  220  are turned on. As a result, a ground voltage VSS is supplied to source terminals of the NMOS transistors N 1 ˜N 3  of the inverter unit  210 . 
         [0062]    After that, when the trigger signal TRIGGER is activated to a high level, the output signal of the NAND gate ND 2  goes to a low level so that the current control device normally operates. 
         [0063]    Subsequently, if the trigger signal TRIGGER is deactivated to a low level and the set signal SET transitions from a high level to a low level, the falling start time of the set signal SET is delayed by the predetermined time by the falling delay unit  310 . In other words, although the set signal SET is transitioned to a low level, the output signal of the falling delay unit  310  maintains a high level for at least the predetermined time. 
         [0064]    Therefore, the pull-down driving signal SETFD maintains a high level for at least the predetermined time, such that the current controller  220  is continuously turned on. If the current controller  220  maintains the turn-on status, the ground voltage VSS is continuously provided to the inverter unit  210  such that an operation time of the storage unit R 1  can be guaranteed. 
         [0065]    After lapse of a delay time of the falling delay unit  310 , the pull-down driving signal SETFD transitions from a high level to a low level, such that each NMOS transistor in the current controller  220  is turned off to prevent the ground voltage VSS from being applied to the inverter unit  210 . As a result, the inverter unit  210  is deactivated. 
         [0066]    The storage unit R 1  latches a previous output level to prevent the output signal of the inverter unit  210  from entering an abnormal status during the ground voltage VSS is not applied to the inverter unit  210 . 
         [0067]    The embodiment of the present invention performs user-desired operations upon receiving the set signal SET, obtains the operation time of the storage unit R 1  using the falling-delayed pull-down driving signal SETFD and the power-down signal PWRDN, and prevents the ground voltage terminal from being coupled to the inverter unit  210  through the current controller  220 . 
         [0068]    On the other hand, when entering the power-down mode, the power-down signal PWRDN transitions to a high level. The output signal of the inverter IV 7  goes to a low level. 
         [0069]    Under this condition, the pull-down driving signal SETFD goes to a low level irrespective of a logic level of the set signal SET, such that it is impossible for the current controller  220  to provide the ground voltage VSS to the inverter unit  210 . As a result, a standby current of the inverter unit  210  and a turn-on current of the transistors in the inverter unit  210  can be reduced. 
         [0070]      FIG. 4  illustrates a circuit diagram of a current control device according to another embodiment of the present invention. 
         [0071]    Referring to  FIG. 4 , the current control device includes an input controller  400 , a drive unit  500 , and a storage unit R 2 . 
         [0072]    The input controller  400  includes a NAND gate ND 4 . The NAND gate ND 4  performs a NAND operation on a trigger signal TRIGGER, a bank active signal BA, and a set signal SET, and outputs the NAND operation result. 
         [0073]    The drive unit  500  includes an inverter unit  510  and a current controller  520 . 
         [0074]    The inverter unit  510  includes pairs of PMOS transistors P 4 ˜P 6  and NMOS transistors N 7 ˜N 9 . In other words, the inverter unit  510  includes a plurality of inverters serially connected in the form of an inverter chain. In another embodiment, the inverter  510  may be composed of a plurality of delay elements connected in series to each other. 
         [0075]    The current controller  520  includes a plurality of pull-down driving elements disposed between the inverter unit  510  and the ground voltage terminal VSS such that the pull-down driving elements are controlled by a pull-down driving signal SETBAFD. The pull-down driving elements are composed of NMOS transistors N 10 ˜N 12 . 
         [0076]    The NMOS transistors N 10 , N 11  and N 12  of the current controller  520  are coupled to the NMOS transistors N 7 , N 8 , and N 9  of the inverter unit  510 , respectively. The NMOS transistors N 10 ˜N 12  receive the pull-down driving signal SETBAFD through a common gate terminal. 
         [0077]    The PMOS transistor P 4 , the NMOS transistor N 7 , and the NMOS transistor N 10  are serially coupled between the power-supply voltage terminal VCC and the ground voltage terminal VSS. The PMOS transistor P 4  and the NMOS transistor N 7  receive an output signal of the NAND gate ND 4  through a common gate terminal. The NMOS transistor N 10  receives the pull-down driving signal SETBAFD through a gate terminal. 
         [0078]    The PMOS transistor P 5 , the NMOS transistor N 8 , and the NMOS transistor N 11  are serially coupled between the power-supply voltage terminal VCC and the ground voltage terminal VSS. A common gate terminal of the PMOS transistor P 5  and the NMOS transistor N 8  is coupled to an inverter element of the previous stage, e.g., an output terminal of the inverter composed of the PMOS transistor P 4  and the NMOS transistor N 7 . The NMOS transistor N 11  receives the pull-down driving signal SETBAFD through a gate terminal. 
         [0079]    The PMOS transistor P 6 , the NMOS transistor N 9 , and the NMOS transistor N 12  are serially coupled between the power-supply voltage terminal VCC and the ground voltage terminal VSS. A common gate terminal of the PMOS transistor P 6  and the NMOS transistor N 9  is coupled to an inverter element of a previous stage. The NMOS transistor N 12  receives the pull-down driving signal SETBAFD through a gate terminal. 
         [0080]    The storage unit R 2  includes latch-type inverters IV 9  and IV 10  in which an input terminal of the inverter IV 9  is coupled to an output terminal of the inverter IV 10  and an output terminal of the inverter IV 9  is coupled to an input terminal of the inverter IV 10 . The storage unit R 2  latches an output signal of the drive unit  500  and outputs an output signal OUT. 
         [0081]      FIG. 5  illustrates a detailed circuit diagram of a drive signal generator  600  for generating the pull-down driving signal SETBAFD used in the current control device shown in  FIG. 4  according to an embodiment of the present invention. 
         [0082]    Referring to  FIG. 5 , the drive signal generator  600  includes an input unit  610 , a falling delay unit  620 , and an output unit  640 . 
         [0083]    The input unit  610  includes a NOR gate NOR 1  and an inverter IV 11 . The NOR gate NOR 1  performs a NOR operation on the set signal SET and the bank active signal BA. The inverter IV 11  inverts an output signal of the NOR gate NOR 1 . If any one of the set signal SET and the bank active signal BA goes to a high level, the input unit  610  enables an output signal of the inverter IV 11  to a high level. 
         [0084]    The falling delay unit  620  delays a falling start time of the output signal of the input unit  610 . That is, if the set signal SET or the bank active signal BA is enabled to a high level, the falling delay unit  620  extends a period of the high level status by a predetermined time, such that a transition start time for the falling status is delayed by the predetermined time. 
         [0085]    The output unit  640  includes inverters IV 12  and IV 13  and a NAND gate ND 5 . The NAND gate ND 5  performs a NAND operation on an output signal of the falling delay unit  620  and an inverted power down signal output from the inverter IV 12  that inverts a power down signal PWRDN. The inverter IV 13  inverts an output signal of the NAND gate ND 5  to output the pull-down driving signal SETBAFD. 
         [0086]    Operations of the current control device shown in  FIG. 4  will hereinafter be described in detail with reference to  FIGS. 4 and 5 . 
         [0087]    In a normal operation mode, not the power-down mode, the power-down signal PWRDN is deactivated to a low level. Accordingly, the inverted power down signal output from the inverter IV 12  has a high level. 
         [0088]    In addition, if any one of the set signal SET and the bank active signal BA transitions from a low level to a high level, the output signal of the NAND gate ND 5  goes to a low level, and the pull-down driving signal SETBAFD corresponding to the output signal of the inverter IV 13  goes to a high level. 
         [0089]    In this case, if the set signal SET and the bank active signal BA go to a high level and the trigger signal TRIGGER goes to a low level, the output signal of the NAND gate ND 4  goes to a high level so that the inverter unit  510  operates. 
         [0090]    When the pull-down driving signal SETBAFD goes to a high level, all the NMOS transistors N 10 ˜N 12  of the current controller  520  are turned on. As a result, a ground voltage VSS is supplied to source terminals of the NMOS transistors N 7 ˜N 9  of the inverter unit  510 . 
         [0091]    After that, when the trigger signal TRIGGER is activated to a high level, the output signal of the NAND gate ND 4  goes to a low level so that the current control device normally operates. 
         [0092]    Subsequently, if the trigger signal TRIGGER is deactivated to a low level and the set signal SET and the bank active signal BA transition from a high level to a low level, the falling start time of the set signal SET or the bank active signal BA is delayed by the predetermined time by the falling delay unit  620 . In other words, although the set signal SET and the bank active signal BA transition to a low level, the output signal of the falling delay unit  620  maintains a high level during at least the predetermined time. 
         [0093]    Therefore, the pull-down driving signal SETBAFD maintains a high level for at least the predetermined time, such that the current controller  520  is continuously turned on. If the current controller  520  maintains the turn-on status, the ground voltage VSS is continuously provided to the inverter unit  510  such that an operation time of the storage unit R 2  can be guaranteed. 
         [0094]    After lapse of a delay time of the falling delay unit  620 , the pull-down driving signal SETIDLEFD transitions from a high level to a low level, such that each NMOS transistor in the current controller  520  is turned off to prevent the ground voltage VSS from being applied to the inverter unit  510 . As a result, the inverter unit  510  is deactivated. 
         [0095]    The storage unit R 2  for latching a previous output level to prevent the output signal of the inverter unit  510  from entering an abnormal status during the ground voltage VSS is not applied to the inverter unit  510 . 
         [0096]    On the other hand, when entering the power-down mode, the power-down signal PWRDN transitions to a high level. The output signal of the inverter IV 12  goes to a low level. 
         [0097]    Under this condition, the pull-down driving signal SETBAFD goes to a low level irrespective of a logic level of the set signal SET or the bank active signal BA, such that it is impossible for the current controller  520  to provide the ground voltage VSS to the inverter unit  510 . As a result, a standby current of the inverter unit  510  and a turn-on current of the transistors in the inverter unit  510  can be reduced. 
         [0098]    As is apparent from the above description, the embodiments of the present invention have the following characteristics. 
         [0099]    First, the current control device according to the embodiments of the present invention controls the path of the ground voltage VSS for use in the semiconductor memory device, such that it can reduce not only the standby current generated in the circuit but also the turn-on current of the transistor according to whether the circuit enters the idle status or the power down mode. 
         [0100]    Second, the current control device according to the embodiments of the present invention reduces not only the standby current but also the turn-on current of the transistor, so that it can implement a low-power semiconductor memory device such as a low-power DRAM device. 
         [0101]    Those skilled in the art will appreciate that the present invention may be carried out in other specific ways than those set forth herein without departing from the spirit and essential characteristics of the present invention. The above exemplary embodiments are therefore to be construed in all aspects as illustrative and not restrictive. The scope of the invention should be determined by the appended claims and their legal equivalents, not by the above description, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein. Also, it is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be presented in combination as an exemplary embodiment of the present invention or included as a new claim by a subsequent amendment after the application is filed. 
         [0102]    Although a number of illustrative embodiments consistent with the invention have been described, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. Particularly, numerous variations and modifications are possible in the component parts and/or arrangements which are within the scope of the disclosure, the drawings and the accompanying claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.