Abstract:
A current control system for an electrical connection device generally includes a first output having a first current rating and a second output having a second current rating. A transistor provides current to the first output and the second output. A sensor is electrically disposed between the transistor and the second output and generates a sensor signal based on a flow of current to the second output. A current control module receives the sensor signal and controls the transistor to provide current based on one of the first and the second current rating.

Description:
FIELD 
   The present teachings relate to methods and systems for controlling current to varying loads using a single output connector. 
   BACKGROUND 
   It is common for an owner of a vehicle, such as an automobile, truck or the like, to tow or trail various trailers, such as a camper trailer, a boat trailer, a storage trailer, or the like. Electrical power is made available to the trailer by means of an electrical wire connector electrically connected to the towing vehicle&#39;s electrical supply system. Vehicle electrical connectors can be made to accommodate connection between the various trailers and the vehicle. For example, the Society of Automotive Engineers (SAE) has promulgated a standardized connection scheme that allows for intermixed connection between various types of vehicles and trailers. 
   In some vehicles, a standardized connection scheme includes two vehicle electrical connectors to allow for intermixed connection between the vehicle and two mutually exclusive trailer connectors. For example, a four pin vehicle electrical connector is provided for lighter duty trailers and a seven pin vehicle electrical connector is provided for heavier duty trailers. Three common circuits between the four and seven pin connectors are Right Turn Stop, Left Turn Stop and Running Lights. The three common circuits are hardwired on the vehicle with a current rating set to heavy duty, seven pin connector drive needs. This leaves the four pin electrical connector and light duty trailer system prone to overload conditions that can damage the connector terminals and the trailer wiring. 
   To ensure that the proper levels of current are supplied to each of the various trailers, a vehicle electrical connector circuit is provided that regulates current to each output of the two vehicle electrical connectors. As shown in  FIG. 1A  and according to various aspects of the prior art, a connector circuit  10   a  provides a fuse  12  and a relay  14  that is controlled by a microprocessor or low current switch  20   a  to ensure that the current level provided to outputs  16  and  18  from a power source  22  does not exceed a predetermined current level. As shown in  FIG. 1B  and according to various aspects of the prior art, a connector circuit  10   b  provides a transistor  24  and  26  for each output  16  and  18  respectively. The transistors  24  and  26  are individually controlled by a microprocessor  20   b  to ensure that the current level provided to the outputs  16  and  18  from the power source  22  does not exceed a predetermined current level. Implementing separate transistors  24  and  26  or a fuse  12  and a relay  14  for outputs  16  and  18  can be costly. 
   SUMMARY 
   The present teachings generally include a current control system for an electrical connection device. The current control system includes a first output having a first current rating and a second output having a second current rating. A transistor provides current to the first output and the second output. A sensor is electrically disposed between the transistor and the second output and generates a sensor signal based on a flow of current to the second output. A current control module receives the sensor signal and controls the transistor to provide current based on one of the first and the second current rating. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present teachings in any way. 
       FIG. 1A  is a block diagram illustrating a current control system that includes a relay and a fuse in accordance with the prior art. 
       FIG. 1B  is a block diagram illustrating a current control system that includes at least two transistors in accordance with the prior art 
       FIG. 2A  is a block diagram illustrating a vehicle including a current control system used for a trailer connector in accordance with various aspects of the present teachings. 
       FIG. 2B  is diagram of an exploded front view of a vehicle electrical connector of  FIG. 2A  in accordance with various aspects of the present teachings. 
       FIG. 2C  is a diagram of an exploded front view of another vehicle electrical connector of  FIG. 2A  in accordance with various aspects of the present teachings. 
       FIG. 3  is a block diagram illustrating a current control system in accordance with various aspects of the present teachings. 
       FIG. 4  is a block diagram illustrating a current control system in accordance with various other aspects of the present teachings. 
       FIG. 5  is a process flow diagram illustrating a current control method as performed by the current control system in accordance with various aspects of the present teachings. 
   

   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present teachings, their application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term module, control module, component and/or device can refer to one or more of the following: an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group) and memory that executes one or more software or firmware programs, a combinational logic circuit and/or other suitable mechanical, electrical or electromechanical components that can provide the described functionality and/or combinations thereof. 
   With reference to  FIG. 2A  and in one aspect of the present teachings, a vehicle  30  that can include a current control system for a vehicle electrical connector system is shown. It can be appreciated in light of the disclosure that the current control system may be applicable to various electrical connection devices. For example, a similar electrical connection device may be used for tractors and trailers and between multiple trailers. For exemplary purposes, various aspects of the current control system will be discussed in the context of vehicle electrical connectors  32  and  33  and at least one trailer electrical connector  34  or  35 . 
   As shown in  FIG. 2A , the vehicle  30  can include at least two vehicle electrical connectors  32  and  33  that can couple to or near a rear end of the vehicle  30 . An exemplary exploded front view of a first vehicle electrical connector  32  is shown in  FIG. 2B . An exemplary exploded front view of a second vehicle electrical connector  33  is shown in  FIG. 2C . The vehicle electrical connectors  32  and  33  can each include a plurality of output pins  38   a - 38   g  and  46   a - 46   d  respectively. The plurality of output pins  38   a - 38   g  and  46   a - 46   d  can mate with a plurality of receptacles, or electrical terminals of a trailer electrical connector  34  or  35 , respectively. 
   In various embodiments, the trailer electrical connectors  34  and  35  can be connected and disconnected to the vehicle electrical connectors  32  and  33 , respectively. One trailer electrical connector  34  or  35  can be connected to the corresponding vehicle electrical connector  32  or  33  at a time. When connected to the vehicle electrical connector  32  or  33 , the trailer electrical connector  34  or  35  can provide current to various electrical systems of the trailer via a wiring harness  40  or  41 . Such systems may include, but are not limited to, tail light systems, turn signal systems, and braking systems. 
   As will be discussed further below, the current control system of the present teachings can include a connector circuit  42  that can detect which trailer electrical connection  34  or  35  is connected to the corresponding vehicle electrical connector  32  or  33  and can provide current at a sufficient rate to control the varying electrical loads of each trailer. Generally speaking, the connector circuit  42  can include one or more devices that can control current to each output pin  38   a - 38   g  and  46   a - 46   d  based on predetermined protection levels that can each indicate a current rating. 
   More specifically, with reference to  FIG. 3 , a block diagram illustrating a connector circuit  42   a  of the current control system in accordance with various aspects of the present teachings is shown. The connector circuit  42   a  can provide current to output pins that can be associated with either the first vehicle electrical connector  32  (connector  1 ) or the second vehicle electrical connector  33  (connector  2 ). A single transistor  48   a  can regulate current from the power source  22  to both output terminals  44   a  and  46   a  based on a control signal  50   a  received from a current control module  52   a . In various aspects, the transistor  48   a  can be a field effect transistor. 
   A sensor  54   a  can be electrically disposed between the transistor  48   a  and the second output terminal  46   a . The sensor  54   a  can sense the presence or absence of current flow to the second output terminal  46   a  once the trailer electrical connector  35  ( FIG. 2A ) is connected to the vehicle electrical connector  33  ( FIG. 2A ). The sensor  54   a  can be, but is not limited to, a thermistor that detects a rise in temperature, a shunt, a Hall Effect sensor, other similar devices and/or one or more combinations thereof. The sensor  54   a  can generate a sensor signal  56   a  to the current control module  52   a . Based on the sensor signal  56   a , the current control module  52   a  can determine which trailer electrical connector  34  or  35  is connected and can regulate the transistor  48   a  based on the predetermined protection levels. In various aspects of the present teachings, the current control module  52   a  can include software for performing a current control method as will be discussed further below. 
   It can be appreciated in light of the disclosure that, for electrical connection devices with multiple output terminals, the transistor and sensor circuitry discussed above can be implemented for each common pair of output terminals between the two trailer electrical connection configurations as discussed above. It can be appreciated in light of the disclosure that multiple sensors can be similarly used for multiple connectors. 
   With reference to  FIG. 4 , a block diagram illustrating a connector circuit  160  of the current control system in accordance with other various aspects of the present teachings is shown. Multiple output terminals  44   a ,  44   b , and  44   c  shown generally at  66  can be used to provide current to the first vehicle electrical connector  32  ( FIG. 2A ) (connector  1 ). Provided the seven output pin example shown in  FIG. 2B , not all output terminals are shown. Multiple outputs terminals  46   a ,  46   b  and  46   c  shown generally at  78  can be used to provide current to the second vehicle electrical connector  33  ( FIG. 2A ) (connector  2 ). Transistors  48   b ,  48   c , and  48   d  can regulate current from the power source  22  to common output terminals of each connector. The transistors  48   b ,  48   c , and  48   d  can operate based on control signals  50   b ,  50   c , and  50   d , respectively, received from the current control module  52   b . In various aspects, the transistors  48   b ,  48   c , and  48   d  can be field effect transistors. 
   A sensor  54   b  can electrically connect to a ground  76  associated with the second vehicle electrical connector  33  ( FIG. 2A ). The sensor  54   b  can sense the presence or absence of current flow to the output terminals  46   a ,  46   b , and  46   c  once the trailer electrical connector  35  ( FIG. 2A ) is connected to the vehicle electrical connector  33  ( FIG. 2A ). The sensor  54   b  can be, but is not limited to a thermistor that detects a rise in temperature, a shunt, a Hall Effect sensor, other suitable devices, and/or one or more combinations thereof. The sensor  54   b  can generate a sensor signal  56   b  to the current control module  52   b . Based on the sensor signal  56   b , the current control module  52   b  can determine which trailer electrical connector  34  or  35  ( FIG. 2A ) is connected and can regulate the transistors  48   b ,  48   c , and  48   d  based on one or more predetermined current levels. In various aspects of the present teachings, the current control module  52   b  can include software for performing a current control method as will be discussed further below. 
   With reference to  FIG. 5 , a process flow diagram illustrating a current control method as performed by the current control system in accordance with various aspects of the present teachings is shown. The method may be run by the current control modules  52   a  or  52   b  of the connector circuits  42   a  and  160  continually during vehicle operation. As can be appreciated, the order of operation of the steps within the method is not limited to the sequential execution as illustrated in  FIG. 5 , but may be performed in one or more varying orders as applicable, in accordance with the present teachings. 
   In one example, the method begins at  100 . A current threshold is initialized to a first predetermined protection level at  110 . In various aspects of the present teachings, the first predetermined protection level can be the higher of the two predetermined levels so as to not deprive a higher electrical load from initially receiving the appropriate current. In various other aspects of the present teachings, the first predetermined protection level can be a lower of the two predetermined levels so as to prevent the possibility of over-powering the lower electrical load. 
   At  120 , the sensor signal  56   a  or  56   b  can be processed. The sensor signal  56   a  or  56   b  can be evaluated at  130  according to the type of sensor implemented in the connector circuit  42   a  or  42   b . For example, if a thermistor were implemented, the sensor signal  56   a  or  56   b  would be evaluated based on a predetermined temperature that would indicate current flow to that output terminal. If the sensor signal  56   a  or  56   b  indicates that current is flowing, the current threshold can be adjusted to the second predetermined protection level at  140 . Otherwise, if the sensor signal  56   a  or  56   b  indicates that current is not flowing at  130 , the current threshold can be maintained at the first predetermined protection level at  150 . Thereafter, the sensor signal  56   a  or  56   b  can be continually processed and evaluated at  120  and  130  while the vehicle  30  is operating. 
   While specific aspects have been described in this specification and illustrated in the drawings, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the present teachings, as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various aspects of the present teachings may be expressly contemplated herein so that one skilled in the art will appreciate from the present teachings that features, elements and/or functions of one aspect of the present teachings may be incorporated into another aspect, as appropriate, unless described otherwise above. Moreover, many modifications may be made to adapt a particular situation, configuration or material to the present teachings without departing from the essential scope thereof. Therefore, it may be intended that the present teachings not be limited to the particular aspects illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the present teachings but that the scope of the present teachings will include many aspects and examples following within the foregoing description and the appended claims.