Patent Abstract:
An electronic circuit in a package, including two functions, the package orientation activating a single one of the two functions.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority benefit of French patent application number 11/56674, filed on Jul. 22, 2011, which is hereby incorporated by reference to the maximum extent allowable by law. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    Embodiments generally relate to electronic circuits and, more specifically, to integrated circuits housed in a package having connection tabs adapted to transfer contacts to other components or other circuits of an electronic device. 
         [0004]    2. Discussion of the Related Art 
         [0005]    Many electronic circuits, be they monolithic circuits, or digital or analog integrated circuits, are assembled in packages to then be assembled with other circuits or components on an electronic board, for example, a printed circuit. 
         [0006]    The packages are generally made of resin or other insulating materials and comprise conductive contacting elements to transfer connections internal to the package to the outside, to establish connections with the other electronic board circuits. 
         [0007]    The connection transfer elements may be conductive contact transfer tabs laterally coming out of the package, conductive bumps at the lower surface of the package to be transferred to corresponding conductive pads of the electronic board, etc. 
         [0008]    As a result of the miniaturization of integrated circuits, the bulk of an electronic circuit is now due more to the package bulk than to the bulk associated with the electronic functions performed by the integrated circuit. This results in a loss of space in packages having a size, among others, conditioned by the elements of connection to the outside and the intervals to be left between these elements to provide an insulation between the different external connections. 
         [0009]    It has already been provided to house, in a same package, several integrated circuits, or a circuit performing several functions, by selecting the function to be used by means of a dedicated external terminal. The circuit connection terminals (tabs or bumps) can then be configured to be assigned to one or the other function. Such a solution requires an additional terminal, which generates an increase of the package size due to its simple presence. 
       SUMMARY 
       [0010]    An embodiment overcomes all or part of the disadvantages of known usual dual-function electronic circuits. 
         [0011]    Another embodiment provides a packaged electronic circuit capable of performing two functions without for any external terminal to be necessary to select the chosen function. 
         [0012]    Thus an embodiment provides an electronic circuit in a package, comprising two functions, the package orientation activating a single one of the two functions. 
         [0013]    According to an embodiment, the circuit comprises, on each of two opposite sides of the package, a first terminal intended to receive a power supply voltage, the respective positions of the first two terminals being symmetrical with respect to the center of the segment connecting the first two terminals. 
         [0014]    According to an embodiment, the circuit further comprises a selector of the activated function according to the direction of the power supply voltage applied between said first terminals. 
         [0015]    According to an embodiment, said selector comprises:
       two terminals of provision of a power supply voltage internal to the electronic circuit; and   a terminal for providing a signal indicative of the circuit orientation.       
 
         [0018]    According to an embodiment, each first terminal is connected to one of said internal power supply terminals by a single MOS transistor. 
         [0019]    According to an embodiment, second terminals are directly connected to one or the other of the functions. 
         [0020]    According to an embodiment, second terminals are connected, via multiplexers, to said functions. 
         [0021]    The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIGS. 1A and 1B  are top views of an embodiment of a packaged electronic circuit in two orientations; 
           [0023]      FIG. 2  is a block diagram of an embodiment of an electronic circuit; 
           [0024]      FIG. 3  shows an embodiment of a selection circuit integrated to the electronic circuit; 
           [0025]      FIGS. 4A and 4B  show an example of application of the circuit of  FIGS. 1A and 1B ; 
           [0026]      FIGS. 5A and 5B  show another example of application of the circuit of  FIGS. 1A and 1B ; and 
           [0027]      FIG. 6  is a block diagram of an alternative embodiment of the electronic circuit. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    The same elements have been designated with the same reference numerals in the different drawings. For clarity, only those elements which are useful to the understanding of the described embodiments have been shown and will be discussed. In particular, the implementation of the functions contained in the circuit has not been detailed, embodiments being compatible with usual integrated circuit manufacturing techniques. Further, the package manufacturing has not been detailed either, embodiments being here again compatible with usual manufacturing techniques. 
         [0029]      FIGS. 1A and 1B  show an embodiment of an electronic circuit in a package  1  in two assembly configurations. Package  1  integrates at least one integrated circuit (not shown in  FIGS. 1A and 1B ). Package  1  supports at least four (in the shown example, eight) contact transfer terminals or elements  12 A,  12 B, and  13 . In the example of  FIGS. 1A and 1B , it is assumed that these elements are tabs of electric connection to a printed circuit board, not shown. Among such tabs, two first tabs (tabs  12 A and  12 B) have a specific function. The two tabs are located on two opposite sides  14 A and  14 B of package  1 . They are besides arranged in positions such that by pivoting package  1  by 180° (in the same plane, that is, without flipping it, the front surface remaining the front surface and the rear surface remaining the rear surface), tab  12 A is in place of tab  12 B and conversely. In other words, terminals  12 A and  12 B are, in the package plane, symmetrical with respect to the center of the segment (virtual line) joining terminals  12 A and  12 B. 
         [0030]    In  FIG. 1A , tab  12 A is located, in the arbitrary orientation of the drawings, at the bottom left of the circuit and tab  12 B is located at the top right, while in  FIG. 1B , tab  12 B is at the bottom left and tab  12 A is at the top right.  FIGS. 1A and 1B  show two orientations, respectively designated with 0 and 1, of the package, the orientation of package  1  conditioning its operation. 
         [0031]    As a variation, the first terminals may have other positions around the package (for example, in the middle of sides  14 A and  14 B), provided to respect the indicated symmetry. 
         [0032]    Tabs  12 A and  12 B are intended to receive the power supply of the circuit(s) contained in the package, that is, they are intended to be connected either to a first positive or negative voltage (in the example, a positive voltage Vdd), or to ground (GND), or to a voltage of opposite sign. The direction (sign) of the D.C. voltage between terminals  12 A and  12 B, which is conditioned by the package orientation, in turn conditions the package function, that is, that of the two functions that it contains which is activated. 
         [0033]    Preferably, to ease the assembly, a visual mark or guide  16  is provided on one of the surfaces of package  1  along one of its sides. This enables the operator or the machine for assembling packages on an electronic circuit board to determine the orientation to be given to the package according to the function to be activated. The example of  FIG. 1  relates to a guide of the type provided in so-called DIL (Dual-in-Line) packages. The guides may be formed in many other ways, for example, a chamfer all along the edge of a package, a small hole in an angle, etc. 
         [0034]      FIG. 2  is a block diagram of an embodiment of integrated circuit  2  contained in a package  1  of the type described in relation with  FIGS. 1A and 1B . 
         [0035]    Circuit  2  integrates two functions  22  (FCT 1 ) and  24  (FCT 2 ). These functions may be active, passive, of variable complexity, digital, analog, etc. The circuits contained in these functions are powered by rails  21  and  23 , respectively at voltages VddInt and GNDInt corresponding to a D.C. internal power supply voltage, positive in the shown example. As a variation, this D.C. voltage is negative or bipolar (an additional terminal then directly providing the ground, if need be). Rails  21  and  23  are connected to output terminals of a selector  3  (SELECT) having as a function to transfer the voltages present on terminals  12 A and  12 B onto rails  21  and  23 , according to the orientation given to package  1  when it is assembled, that is, according to the direction of the voltage between terminals  12 A and  12 B. 
         [0036]    The other terminals  13  of package  1  are, in the example shown in  FIG. 2 , respectively assigned, for three of them, to function  22 , and for the other three to function  24 . Accordingly, in this example, according to the package assembly direction, three of tabs  13  are left floating, that is, are not connected to the electronic circuit board. 
         [0037]      FIG. 3  is an electric diagram of an embodiment of selector  3  of  FIG. 2 . This selector is for example based on MOS transistors and has the function of automatically transferring, between terminals  21  and  23 , the voltage applied between terminals  12 A and  12 B, in one direction or the other according to the circuit orientation. 
         [0038]    Further, selector  3  provides a signal “Orientation” on a conductor  25 . Signal Orientation is transmitted to circuits  22  and  24  to respectively activate/deactivate them according to the state of this signal. 
         [0039]    Circuit  3  is based on a network of two N-channel transistors MOS  31  and  33  and of two to P-channel MOS transistors  32  and  34 , cross connected. Transistor  31  directly connects terminal  12 A to terminal  23 . Transistor  33  directly connects terminal  12 B to terminal  23 . Transistor  34  directly connects terminal  12 B to terminal  21 . Transistor  32  directly connects terminal  12 A to terminal  21 . Further, the gates of transistors  31  and  32  are interconnected to terminal  12 B and the gates of transistors  33  and  34  are interconnected to terminal  12 A. The bulks of transistors  32  and  34  are interconnected to terminal  21 . The bulks (not shown) of transistors  31  and  33  are interconnected to terminal  23 . 
         [0040]    The four MOS transistors  31  to  34  form a rectifying bridge, reducing voltage losses. 
         [0041]    Signal Orientation is for example generated by means of an inverter  36  powered between terminals  21  and  23  and having its input directly connected to terminal  12 B. 
         [0042]    When external voltage Vdd is applied to terminal  12 A and the ground is applied to terminal  12 B, transistor  31  is blocked while transistor  33  is conductive (positive gate-source voltage). Further, transistor  34  is blocked and transistor  32  is conductive (negative gate-source voltage). As a result, voltage Vdd is transferred onto terminal  21  while the ground voltage is transferred onto terminal  23 . Signal Orientation thus has a state 1 (inverter input at state 0). 
         [0043]    Conversely, if external voltage Vdd is applied to terminal  12 B and the external ground is applied to terminal  12 A, transistors  31  and  34  are conductive and transistors  32  and  33  are blocked. As a result, terminal  12 B is connected to terminal  21  and terminal  12 A is connected to terminal  23 . Signal Orientation has a state 0. 
         [0044]    It should be noted that internal voltage VddInt is always applied in the same direction within the circuit. The difference of application direction from the outside conditions the function executed by the circuit. 
         [0045]    Other embodiments of a selection circuit  3  can be envisaged. However, the embodiment shown in  FIG. 3  has the advantage of generating no substantial voltage drop in crossing the selector, only ohmic losses being generated. 
         [0046]      FIGS. 4A and 4B  illustrate an example of application of an electronic circuit such as described by the above drawings to the generation of a power supply voltage having its value V 1  or V 2  depending on the circuit orientation. 
         [0047]    Package  1 ′ is assumed to only comprise four external connection tabs or terminals. Circuit  1 ′ is assembled on a printed circuit board  4  which provides, at the location of package  1 ′, three pads  41 ,  43 , and  45  intended to be connected to three of the four tabs of package  1 ′ according to its orientation. Pad  41  is connected to a ground conductor (GND) of board  4 . Pad  43  is connected to a positive power supply conductor Vdd of board  4 . Pad  45  provides to other circuits, not shown, of board  4  with a voltage V 1  or V 2  according to the orientation of package  1 ′. 
         [0048]    In this example, functions  22  and  24  ( FIG. 2 ) respectively are a voltage regulator providing level V 1  and a voltage regulator providing level V 2 . Thus, according to the orientation given to circuit  1 ′ on board  4 , said circuit automatically provides one or the other of the two voltage levels. 
         [0049]      FIGS. 5A and 5B  illustrate another example of application to an embodiment of a package  1 ″ containing an EEPROM and its control circuits. In this example, package  1 ″ comprises 2n+2 external connection terminals. n terminals on each side of the package are used to connect the signals associated with the application. For example, according to the orientation of package  1 ″, said package is capable of communicating with the outside according to a protocol known as SPI or according to another protocol known as I2C. The actual nature of the protocol is of no importance. What is desired to be underlined herein is that the memory circuit is capable of operating according to one mode or another according to its orientation. 
         [0050]    The examples of  FIGS. 4A ,  4 B,  5 A, and  5 B illustrate cases where the functions performed by the package are of same nature. However, it may also be provided to integrate, in the same package, electronic circuits performing different functions. 
         [0051]      FIG. 6  is a block diagram of an alternative embodiment  2 ′ of the circuits contained in the package. It shows the two functions (block  22 , FCT 1  and  24 , FCT 2 ) and selector  3  as in  FIG. 2 . However, it is here assumed that the other circuit terminals (in the example,  4 ) are all used whatever the activated function. As many two-to-one, one-to-two, or bidirectional multiplexers  16 , according to the type of function performed by circuits  22  and  24 , as there are terminals  13  are thus provided, to connect each terminal  13  to one of the corresponding terminals of blocks  22  and  24 . Multiplexers  26  are controlled together by signal Orientation provided by selector  3 . 
         [0052]    It is now possible to take advantage of the discrepancy between the miniaturization of packages and the miniaturization of integrated circuits. 
         [0053]    Another advantage of the described embodiments is that their implementation requires no additional terminal on the package to select its function. 
         [0054]    The fact of using dual-function packages means a significant saving for integrated circuit manufacturers. Indeed, the additional cost due to the addition of a useless function in a package is negligible as compared with the cost generated by the inventory management and to logistics of two families of integrated circuits. 
         [0055]    Various embodiments have been described, various alterations and modifications will occur to those skilled in the art. In particular, the implementation of the described embodiments is within the abilities of those skilled in the art based on the functional indications given hereabove. Similarly, the number of terminals depends on the application. 
         [0056]    Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and the scope of the present invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The present invention is limited only as defined in the following claims and the equivalents thereto.

Technology Classification (CPC): 6