Patent Publication Number: US-2003235721-A1

Title: Redundant battery connections

Description:
TECHNICAL FIELD  
       [0001] The present invention relates generally to the field of electronics and, in particular, to redundant battery connections.  
       BACKGROUND  
       [0002] In many applications, electronic modules, such as telecommunications modules, include a number of circuit cards, e.g., line cards, management cards, or the like. Many of these circuit cards have power supplies, e.g., DC-to-DC power supplies or converters, for providing voltages to electronic components of the cards, such as logic devices or the like. These power supplies are usually connected to a battery for receiving power. Frequently, redundant batteries, e.g., a primary battery and a secondary (or backup) battery are connected to the power supplies of each of the circuit cards so that when the primary battery fails the secondary battery takes over for the primary battery to power the electronic module.  
       [0003] In many telecommunications applications, for example, power sides of the primary and secondary batteries usually are respectively connected to separate power paths of the electronic module that are connected together at a power pin of the power supply of each of the circuit cards. Battery-returns of the primary and secondary batteries are usually connected to a common battery-return path of the electronic module that is connected to a battery-return pin of the power supply of each of the circuit cards. However, this creates a single-point of failure within the electronic module for the redundant batteries. For example, an over voltage on the power side can cause a failure at the battery-return pin of the power supply of one of the circuit cards that will disconnect the battery-return sides of both the primary and secondary batteries from the electronic module, e.g., the power supplies of the other circuit cards of the electronic module, resulting in a loss of power to the electronic module.  
       [0004] For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for eliminating single-point of failures within electronic modules for redundant batteries.  
       SUMMARY  
       [0005] The above-mentioned problems with redundant batteries and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification.  
       [0006] One embodiment provides a circuit card having a substrate. A power supply is disposed on the substrate. A pair of traces is disposed within or on the substrate. The pair of traces is connected together at a battery-return pin of the power supply. One of the pair of traces is connectable to a battery-return side of a primary battery, and another of the pair of traces is connectable to a battery-return side of a secondary battery that replaces the primary battery when the primary battery fails.  
       [0007] Another embodiment provides an electronic module having a circuit card with a power supply. The electronic module has two independent battery-return paths. One of the two independent battery-return paths is connectable to a battery-return side of a primary battery, and another of the two independent battery-return paths is connectable to a battery-return side of a secondary battery that replaces the primary battery when the primary battery fails. The two independent battery-return paths are connected together at a battery-return pin of the power supply.  
       [0008] Another embodiment provides an electronic module having a backplane. A pair of first traces is disposed within or on the backplane. One of the pair of first traces is connectable to a battery-return side of a primary battery, and another of the pair of first traces is connectable to a battery-return side of a secondary battery that replaces the primary battery when the primary battery fails. A circuit card is electrically connected to the backplane such that each of a pair of second traces disposed within or on the circuit card is respectively connected to each of the pair of first traces disposed within or on the backplane. The pair of second traces is connected together at a battery-return pin of a power supply of the circuit card.  
       [0009] Other embodiments are described and claimed. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010]FIG. 1 illustrates an electronic module according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
     [0011] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense.  
     [0012] Embodiments of the present invention provide for respectively connecting battery-returns of a primary battery and a secondary battery to independent battery-return paths of an electronic module. The independent battery return paths are connected together at a battery-return pin of a power supply on a circuit card of the electronic module. This eliminates a single-point of failure within the electronic module for the redundant batteries created by connecting battery-returns of primary and secondary batteries to a common battery-return path of an electronic module and connecting the common battery-return path to a battery-return pin of a power supply on a circuit card of the electronic module.  
     [0013]FIG. 1 illustrates an electronic module  100 , such as an electronic module of a telecommunications system. Electronic module  100  includes a backplane  102  having electrical connectors  104   1  to  104   N  electrically connected thereto. Circuit cards  106   1  to  106   N  are respectively connected to each of connectors  104   1  to  104   N  and thus to backplane  102 . In one embodiment, circuit cards  106  are line cards, management cards, or the like of a telecommunications system. Electronic module  100  is connectable to redundant batteries  108  that include a primary battery  110  and a secondary battery  112  that replaces primary battery  110  when primary battery  110  fails, e.g., cannot provide enough power to power electronic module  100 .  
     [0014] Traces  114  and  116  are disposed within or on backplane  102  for respectively providing separate battery-return paths for primary battery  110  and secondary battery  112 . In particular, trace  114  is connectable to a battery-return side  118  of primary battery  110 , and trace  116  is connectable to a battery-return side  120  of secondary battery  112 . In one embodiment, traces  114  and  116  are respectively connected to battery-return pins  122  and  124  of each of connectors  104   1  to  104   N .  
     [0015] Traces  126  and  128  are disposed within or on backplane  102  for respectively providing separate power paths for primary battery  110  and secondary battery  112 . In particular, trace  126  is connectable to a power side  130  of primary battery  110 , and trace  128  is connectable to a power side  132  of secondary battery  112 . In one embodiment, traces  126  and  128  are respectively connected to power pins  134  and  136  of each of connectors  104   1  to  104   N .  
     [0016] Each of circuit cards  106   1  to  106   N  includes a substrate  138 . A power supply  140 , e.g., a DC-to-DC power supply or converter, is disposed on substrate  138 . Functional circuitry  142 , such as logic devices or the like, is also disposed on substrate  138  and is connected to power supply  140  for receiving power therefrom. Traces  146  and  148  are disposed within or on substrate  138  and are connected together at a battery-return pin  150  of power supply  140 . In one embodiment, traces  146  and  148  are respectively connected to battery-return pins  152  and  154  of an edge connector  156  disposed on substrate  138 .  
     [0017] The edge connector  156  of each of circuit cards  106   1  to  106   N  respectively connects each of circuit cards  106   1  to  106   N  to each of connectors  104   1  to  104   N  of backplane  102 . Connecting circuit cards  106  to connectors  104  respectively connects battery-return pins  152  and  154  of the edge connector  156  of each of circuit cards  106  to battery-return pins  122  and  124  of each of connectors  104 . This respectively connects traces  146  and  148  of each of circuit cards  106  to traces  114  and  116  of backplane  102  so that battery-return sides  118  and  120  are connected together at the battery-return pin  150  of the power supply  140  of each of circuit cards  106 .  
     [0018] Traces  158  and  160  are disposed within or on substrate  138  and are connected together at a power pin  162  of power supply  140 . In one embodiment, traces  158  and  160  are respectively connected to power pins  164  and  166  of edge connector  156 . Connecting circuit cards  106  to connectors  104  respectively connects power pins  164  and  166  of the edge connector  156  of each of circuit cards  106  to power pins  134  and  136  of each of connectors  104 . This respectively connects traces  158  and  160  of each of circuit cards  106  to traces  126  and  128  of backplane  102  so that power sides  130  and  132  are connected together at power pin  162  of the power supply  140  of each of circuit cards  106 .  
     Conclusion  
     [0019] Embodiments of the present invention have been described. The embodiments provide for respectively connecting battery-returns of a primary battery and a secondary battery to independent battery-return paths of an electronic module. The independent battery return paths are connected together at a battery-return pin of a power supply on a circuit card of the electronic module. This eliminates a single-point of failure within the electronic module for the redundant batteries created by connecting battery-returns of primary and secondary batteries to a common battery-return path of an electronic module and connecting the common battery-return path to a battery-return pin of a power supply on a circuit card of the electronic module.  
     [0020] Although specific embodiments have been illustrated and described in this specification, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. For example, the term “pin” should not be limited to a specific physical design, but is intended to represent any electrical interconnection. In addition, the power sides of primary battery  110  and secondary battery  112  are not limited to positive polarities, and the battery-return sides of primary battery  110  and secondary battery  112  are not limited to negative polarities, as shown. Instead, the power sides of primary battery  110  and secondary battery  112  can have negative polarities, and the battery-return sides of primary battery  110  and secondary battery  112  can have positive polarities. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof.