Abstract:
An electric circuit is provided with a single jack for connection to either a first remote powered device via a first plug or a second remote unpowered device via a second plug. A power requirement detection circuit is provided for generating a control signal representing whether the connected plug is the first plug or the second plug. A normally deactivated switch is connected between the power source and the jack and is operable to supply power to the jack when activated. A switch activation circuit is responsive to the control signal for actuating the switch when the first plug is connected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/056,241; filed Sep. 26, 2014, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates in general to electrical and electronic connectors. In particular, this invention relates to a connection circuit having one or more receptacles for coupling a first electronic device to a second electronic device where the coupling determines and provides a required power level to the first device. In a preferred embodiment, the invention relates to a wheelchair drive control system having a power sensing connector to facilitate interfacing of peripheral devices to the drive control unit. 
         [0003]    Powered wheelchairs rely on peripheral input and sensing devices to control operation of the drive system and compensate for the physical limitations and disabilities of the user. Some wheelchair users have significant cognitive and physical limitations to operate standard input devices, such as a joystick or touch pad. Peripheral input devices, such as sip-and-puff inputs, head array controls, chin controls, and the like provide alternative means to operate a wheelchair and accommodate a user&#39;s special needs. These devices rely on various sensors and may have different power and signal connection requirements. Some peripherals may be switch devices that do not require power, others may include sensors that depend on charge or voltage inputs to function. Typically, when various peripheral devices have signal and power requirements to operate, separate power and data feeds are provided to energize these devices and provide the necessary signal communication with the controller. Such an arrangement necessitates separate connections, wiring harnesses, and logistics in cable routing to power these devices and connect them with the controller. In addition, multiple connectors and wires adds complexity and cost to wheelchair systems in order to accommodate the wide range of adaptive devices necessary for satisfying disparate user requirements. It would be desirable if a connector system could determine the power and data connection requirements of a peripheral device and provide the necessary electrical and electronic feeds to operate the device automatically. 
       SUMMARY OF THE INVENTION 
       [0004]    This invention relates to a connection receptacle for coupling a first electronic device to a second electronic device where the coupling determines and provides a required power level to the first device. In a preferred embodiment, the invention relates to a wheelchair drive control system having a power sensing connector to facilitate interfacing of peripheral devices to the drive control unit. 
         [0005]    In particular, the invention provides an electric circuit for connection to either a first remote powered device or a second remote unpowered device. The first remote device has a first plug requiring connection to a power source and the second remote device has a second plug not requiring connection to the power source. The circuit comprising a single jack (which may be a T/R/S type jack, or any suitable plug and jack design) adapted to be connected to either the first plug or the second plug. A power requirement detection circuit is provided for generating a control signal representing whether the connected plug is the first plug or the second plug. A normally deactivated switch is connected between the power source and the jack and is operable to supply power to the jack when activated. A fuse may optionally be connected between the switch and the power source. A switch activation circuit is responsive to the control signal for actuating the switch when the first plug is connected, and for maintaining the switch in a deactivated state when the second plug is connected. The switch activation circuit may optionally include a soft start circuit for gradually activating the switch. 
         [0006]    Optionally, the electric circuit may include a plug insert detection circuit for generating a second control signal representing whether either the first or second plug has been connected to the jack. In this case, the switch activation circuit is responsive to the first and second control signals. The electric circuit according to claim  1  and further including a fuse connected between the switch and the jack. Preferably, the first remote device is operable to provide a first data signal to the electric circuit via the first plug, and wherein second remote device is operable to provide a second data signal to the electric circuit via the second plug. 
         [0007]    Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a power wheelchair having a power sensing connector in accordance with the invention. 
           [0009]      FIG. 2A  is a perspective, exploded view of a sin and puff input device. 
           [0010]      FIG. 2B  is a perspective view of a microlight accessory device. 
           [0011]      FIG. 2C  is a perspective view of a chin control accessory device. 
           [0012]      FIG. 3  is an exploded view of another embodiment of a power sensing connector in accordance with the invention. 
           [0013]      FIG. 4A  is a perspective view of a tip-sleeve male connector. 
           [0014]      FIG. 4B  is a perspective view of a tip-ring-sleeve male connector. 
           [0015]      FIG. 4C  is a perspective view of a tip-ring-ring-sleeve male connector. 
           [0016]      FIG. 5A  is a schematic illustration of a simplified block diagram of the invention under the conditions of receiving a plug that requires a power source. 
           [0017]      FIG. 5B  is a schematic illustration of a simplified block diagram of the invention under the conditions of receiving a plug that does not require a power source. 
           [0018]      FIG. 6  is a flow chart illustrating the steps associated an algorithm in accordance with the invention. 
           [0019]      FIG. 7  is a circuit diagram of an embodiment of a power sensing connector in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring now to the drawings, there is illustrated in  FIG. 1  a power driven wheelchair, shown generally at  10 . The exemplary power wheelchair is illustrated as a mid-wheel drive wheelchair, however, it should be understood that the power driven wheelchair  10  may be of a front wheel drive configuration, rear wheel drive configuration, or other suitable drive configuration. The wheelchair  10  includes drive wheels  12  and stabilizing caster wheels  14  as are well known in the art. The wheelchair  10  further includes a seat  16  and backrest  18 . The power driven wheelchair  10  includes a controller  20  that receives command inputs from an input device, such as a joystick  22 . In the illustrated embodiment, the joystick  22  includes a power sensing connector system  24 . While illustrated as part of the joystick  22 , in other embodiments the power sensing connector system  24  may also be configured as a separate system, as will be described in conjunction with  FIG. 3 . 
         [0021]    As shown in  FIGS. 2A-2C , there are illustrated three examples of various peripheral devices that may be used with the power sensing connector system  24 .  FIG. 2A  is a sip-and-puff input device  26 . In one embodiment, the sip-and-puff input device  26  may be configured to operate as a passive switch, which does not need a power supply to operate. Other embodiments of the sip-and-puff input device  26  may utilize power to operate.  FIG. 2B  is a chin control input device  28 , which may also be configured as a passive switch that does not require power to operate.  FIG. 2C  is a micro-light  30  peripheral accessory that is an example of an active device that requires a power source to operate. These peripheral devices are merely examples of various passive and active peripheral accessory devices. Other devices, such as cellular phones, computers, home assistance devices, and other operational input devices and sensors are other examples of devices suitable for use with the embodiments of the power sensing connector system  24 . Thus, any suitable peripheral device may be used and remain within the scope of the invention. 
         [0022]    Referring now to  FIG. 3 , there is illustrated another embodiment of a power sensing connector system  32 . This embodiment of the power sensing connector system  32  operates in a similar manner to the power sensing connector system  24  yet is packaged as a separate unit that may be adapted to an existing wheelchair controller system, rather than being integrated into another component. The power sensing connector system  32  includes a plurality of jacks  34 . The connectors  34  are in electrical communication with a circuit board  36 . The circuit board  36  includes an electronic circuit that carries out the operational steps illustrated in  FIG. 6 . In one embodiment, the electronic circuit of circuit board  36  is illustrated by a circuit diagram  100  of  FIG. 7 . A controller lead  38  connects the various jacks  34  to the controller  20  such that data may be transmitted between the controller  20  and any of the various peripheral devices along with a power source, such as for example a 12 volt power source. The power source is configured to supply voltage and current levels sufficient to energize and operate the peripheral devices. In one embodiment, these voltage and current levels may be in a range of about 2 volts to about 12 volts and in a current capacity of about 1 ampere to about 15 amperes. The power supply supplies power levels higher that what is understood to be a low current biasing voltage power level. The components of the power sensing connector system  32  are enclosed in a housing  40   a  and  40   b.    
         [0023]    Referring now to  FIGS. 4A ,  4 B, and  4 C, there are illustrated three types of male connectors, broadly characterized as phone connectors, though other types of connectors may be used if desired.  FIG. 4A  is a tip-sleeve or TS male connector shown generally at  42 . The TS connector  42  includes a tip contact  42   a  and a sleeve contact  42   b . Generally, the tip contact  42   a  is configured to transmit data, such as sensor information or control output signals to the controller  20 . The sleeve contact  42   b  is typically configured as a common or ground contact that completes a communication circuit between the peripheral device and the controller  20 . Often, the TS connector is used in conjunction with passive, or unpowered, devices.  FIG. 4B  illustrates a tip-ring-sleeve or TRS connector  44 . The TRS connector  44  includes a tip contact  44   a,  similar to tip contact  42   a , that transmits data between the peripheral device and the controller  20 . A sleeve contact  44   c  is functionally similar to sleeve contact  42   b  as providing an electrical ground. In this particular embodiment, the sleeve contact  44   c  is shorter in length than the sleeve contact  42   b . The TRS connector  42  includes a ring contact  44   c,  disposed between the tip contact  44   a  and the sleeve contact  44   c.  The ring contact  44   c  is configured to provide power, such as an operating voltage and current level, to an active peripheral device. Referring to  FIG. 4C , there is illustrated a third connector configured as a tip-ring-ring-sleeve or TRRS connector  46 . The TRRS connector  46  is similar to TRS connector  44  in that there is a tip contact  46   a  and a sleeve contact  46   d,  configured similarly to the TS and TRS connectors  42  and  44 , respectively. The TRRS connector  46  includes first and second ring contacts  46   b  and  46   c.  These ring contacts  46   b  and  46   c  may be configured to supply power to the peripheral device, provide addition data or command signals or provide a charging service for remote power sources used in the peripheral device. 
         [0024]      FIG. 5A  shows a simplified block diagram of the invention under the conditions of receiving a plug that requires a power source  48 , which may be a DC power source, AC power source, or any other power source desired. The plug may be of any type that has a dedicated contact to receive power from the host device that houses the jack. A common type of plug that would work for this purpose is the T/R/S phone connector  44  which has the tip, ring and sleeve contact, as described above. The tip  44   a  can be used to carry a signal to or from a remote device while the ring  44   b  can be the dedicated contact for the power supplied to that remote device. The sleeve  44   c  is typically a shared ground for the two other contacts. The invention has a plug insert detection sub-circuit  50  which through some means of mechanical and/or electrical sensing is able to confirm if there is a plug present in the jack. The invention also has the ability to detect if the remote device requires power. In the case of a using a T/R/S plug, the power requirement detection sub-circuit  52  will sense the existence of the ring contact  44 b as well as its ability to receive power. If it is confirmed that the remote device requires power, the resulting output of the sub-circuit  52  will be a logic TRUE. If the plug insert detection sub-circuit also results with a logic TRUE, then the logic combining sub-circuit or switch activation circuit  54  will allow switch  56  to close. This will allow power to be supplied to the power contact on the plug. The switch may be in the form of a semiconductor, such as a MOSFET. Or, it may be an electro-mechanical type, such as a relay. If either sub-circuit  50  or sub-circuit  52  provide a logic FALSE, then the switch  56  will remain open and not close. 
         [0025]      FIG. 5B  shows a simplified block diagram of the invention under the conditions of receiving a plug that does not require a power source. The plug may be of any type that does not have a dedicated contact to receive power from the host device that houses the jack. If an embodiment uses the previously mentioned phone connector type plug, a device that does not require power may use the version of T/S plug  42  on that plug where there is no ring contact present. There is only the tip  42   a  and a sleeve  42   b . In this case, if a T/S plug (or any plug that does not require power) is inserted into the jack, the power requirement detection sub-circuit  52  will not sense the existence of a ring or dedicated power contact, and the sub-circuit will output a logic FALSE. Also in this particular case, the plug insert detection circuit will still sense the plug present in the jack, and this results in a logic output of TRUE. However, because sub-circuit  52  and sub-circuit  54  are not both TRUE, the switch  56  will not close. This allows a non-powered remote device to operate normally while also preventing damage to the power supplying circuitry or the remote device itself. 
         [0026]      FIG. 6  describes the logical flow in the operation of the invention. When a plug is inserted into the jack at step  60 , it must be determined if the device (switch for example) connected is of the passive or active type at step  62 . A passive device will not require a power, and an active device will require power to be supplied to it in order to function. If the plug is sensed to come from a passive device, the switch remains open and no power is supplied to the plug in step  64 . If the plug is sensed to come from an active power requiring device such as a sensor, at step  66  the switch is closed and power is then applied in a slow and gradual manner as in step  68  so as to not damage the device or the power supply. 
         [0027]      FIG. 7  shows a more detailed schematic of a preferred embodiment of the invention. A connector J 1  is shown as a female T/R/S jack that includes contacts for the tip, ring and sleeve of a plug (not shown in  FIG. 7 ). The sleeve, pin  5  on the connector J 1 , is connected to the circuit ground. Pin  1  is the dedicated contact for the ring of a plug, and pin  4  is the dedicated contact for the tip of a plug. Pins  2  and  3  are mechanical switch contacts that make contact with pins  1  and  4  only if there is no plug in the jack. The insertion of a plug will separate pins  2  and  3  from pins  1  and  4 , respectively. This can be useful for sensing when a plug is inserted. 
         [0028]    A pull-up resistor R 7  is connected between a voltage source (shown as 12 volts) and the ring (pin  1 ) of connector J 1 . If there is no plug in the connector J 1 , a high level signal on line  100  will conduct through J 1  pin  1  to J 1  pin  2 , and eventually through a diode D 5  to the gate (pin 3 ) of an (upper) p-channel MOSFET in a complimentary MOSFET component, U 3 . The U 3  p-channel MOSFET will be maintained in an OFF state when its gate (pin  3  on U 3 ) is pulled up to a high level. When in an OFF state, the U 3  p-channel MOSFET will have a low level signal at its drain (pin  4 ) on line  102 , due to a pull down resistor R 4 . 
         [0029]    If a plug is inserted into the J 1  connector, J 1  pin  1  will disconnect from J 1  pin  2 , and the gate of the U 3  p-channel MOSFET will be pulled down to a low level by pull-down resistor R 9 . This will allow the U 3  p-channel MOSFET to turn ON, and the high level signal present at its source (pin  2 ) will be supplied to its drain (pin  4 ). 
         [0030]    When the U 3  p-channel MOSFETis ON, the high level signal on the line  102  will be supplied to resistor R 8  and charge capacitor C 5 . This is a soft-start circuit that will delay the turn-on of a (lower) n-channel MOSFET in component U 1 , providing a ramped signal at U 1 , pin  5  (gate of the U 1  n-channel MOSFET). The turn-on delay of the U 1  n-channel MOSFET will also delay the turn on of the (upper) p-channel MOSFET in U 1 . When the U 1  p-channel MOSFET is ON, high-current power from the voltage source will flow through pins  4  and  3  of U 1 , through the fuse F 1 , and to the pin  1  ring contact of connector J 1 . 
         [0031]    When the plug includes a ring for supplying power to the device, the line  100  will be at a high level. When no ring is present on the plug, the line  100  will be connected to ground, and therefore at a low level. A complementary MOSFET component U 2  is used to monitor the line  100 , and then control the signal on a line  104  which connects the drain (pin  6 ) of a U 2  (lower) n-channel MOSFET to pin  5  of U 1 . If its gate (pin  1  on U 2 ) is at a high level, the U 2  n-channel MOSFET does not allow the U 1  n-channel MOSFET switch to turn on, by keeping pin  5  of U 1  at a low level. This will occur if there is no ring present on a plug inserted into connector J 1 . In this case the plug&#39;s grounded sleeve will be in contact with pin  1  on the connector J 1 , and the gate of the U 2  (upper) p-channel MOSFET (pin  3 ) will be grounded, causing the U 3  p-channel MOSFET to turn on. As a result, a regulated voltage from regulator U 4  will pass through pins  3  and  4  on U 2  and turn on the U 2  n-channel MOSFET gate on pin  1 . If there is a ring present to accept power on the plug, pin  1  on J 1  will be at a high impedance, and the gate at pin  3  of the U 3  p-channel MOSFET will be at a high level. This will not allow the U 2  p-channel MOSFET to conduct the regulated U 4  voltage to the complimentary U 2  n-channel MOSFET gate (pin  1 )which will then be pulled to ground by pull-down resistor R 1 . In this case, the U 2  n-channel MOSFET will be OFF such that pin  5  of U 1  in unaffected by U 2 . Therefore, the ramped voltage signal at U 1 , pin  5 , will cause the MOSFET switch U 1  to turn on and provide high-current power to the plug. 
         [0032]    To summarize the logical operation of this circuit, if no plug is inserted into connector J 1 , then the plug detecting sub-circuit comprising U 3  will not apply a turn-on voltage to high-current MOSFET switch Ui. If a plug without a power accepting ring is inserted into the connector, the plug detecting sub-circuit comprising U 3  will attempt to turn on switch U 1 , but the ring detecting sub-circuit comprising U 2  will prevent that because it does not sense a ring on the plug. If a plug with a power-accepting ring is inserted into the connector, the sub-circuit comprising U 3  will attempt to turn on switch U 1 . Because a ring is detected by the ring detecting sub-circuit, U 2  will not prevent U 1  from slowly applying power to the pin  1  of the female connector. 
         [0033]    The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.