Abstract:
A single switch is utilized within a common ground line to control the current flow through a plurality of loads, whereby power to all of these loads may be interrupted by opening the system ground return so that power can be supplied to a particular component of the circuit, a microprocessor, to the exclusion of all remaining components by the operation of a single switch.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates in general to an electrical circuit which is capable of isolating particular components while supplying power to a particular device and, more particularly, to an electrical circuit whereby supporting devices in the circuit may be shut down, while power continues to be supplied to a circuit controller without maintaining the surrounding support devices thereby reducing current consumption to near zero. 
     In the design of electrical circuits, it is customary that the positive supply is opened when it is desired to interrupt or terminate power to the circuit or components thereof. However, when it is desired to supply power to a particular component of a circuit, the particular circuit component can be maintained in an operable condition without maintaining surrounding support devices by shutting down the return mode, not the supply mode of the system, by opening the system ground return rather than interrupting the positive supply. In this manner, the current consumption can be limited to that required for maintaining the particular circuit component active, and has many practical applications wherein it is desired to conserve a power supply such as a battery. 
     Interrupting the power supply to a circuit by opening the system ground return rather than the positive supply is known to those skilled in the art, and has been used in circuits for such things as power line load control, U.S. Pat. No.3,448,361, and in a timing controller, in U.S. Pat. No. 4,672,232. In U.S. Pat. No. 3,448,361, “SELECTIVE-FREQUENCY POWER LINE LOAD CONTROL”, a semi-conductor controlled rectifier (SCR) is coupled between an individual load coupled to a power line, and ground. In operation an individual load is coupled in series with the SCR across the power lines, and when the control electrode of the SCR is triggered “on” by a control voltage, current flows through the load. Current flow is interrupted when the control electrode is not triggered, thereby interrupting power to the load on the system ground return. In U.S. Pat. No. 4,672,232, “MICROPROCESSOR OPERATED TIMING CONTROLLER”, an electronic switching device is coupled between an individual load, an appliance receiving receptacle, and ground. In operation the electronic switch is controlled by a microprocessor, which closes the switch to complete a circuit for energizing the receptacle. In the absence of a control signal from the microprocessor, the electronic switch opens the return path to ground, and the appliance plugged into the receptacle is turned off. 
     In the instant circuit, a single switch is utilized within a common ground line to control the current flow through a plurality of loads, whereby power to all of these loads may be interrupted by opening the system ground return so that power can be supplied to a particular component of the circuit, a microprocessor, to the exclusion of all remaining components by the operation of a single switch. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to more efficiently utilize power supplied to an electrical circuit, including a plurality of circuit components and associated support devices. 
     Another object of this invention is to maintain a supply of power to a particular device in an electrical circuit at all times while selectively interrupting the power supplied to the remaining circuit devices receiving power from the same power supply. 
     A further object of this invention is to interrupt the power supplied to a plurality of loads coupled to a common power supply through the use of a single switch while maintaining power to a particular circuit component from the same power supply. 
     Still another object of this invention is to reduce the current consumption of an electrical circuit by opening the system ground to terminate the power supplied to a plurality of loads coupled to the circuit while maintaining the power supply to a particular component of the circuit. 
     These and other objects are attained in accordance with the present invention wherein there is provided an electrical circuit including a microprocessor or controller to which power is supplied at all times and a plurality of supporting devices to which power to the support devices maybe interrupted by operation of a single switch situated within a common ground line for the plurality of support devices, controlled by operation of the microprocessor controller. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Further objects of this invention, together with additional features contributing thereto and advantages accruing therefrom, will be apparent from the following description of a preferred embodiment of the present invention which is shown in the accompanying drawings with like reference numerals indicating corresponding parts throughout and which is to be read in conjunction with the following drawings, wherein: 
     FIG. 1 is a frontal perspective view of an incentive spirometer with a detachable goal-recording counter supported thereon in a position to record the occurrence of a completed predetermined event and incorporating the invention of this application; 
     FIG. 2 is a logic block diagram or flow chart to better illustrate the manner in which the electrical circuit of the goal-recording counter records the occurrence of a properly executed event and displays to a user when such a properly executed event has been performed; and 
     FIG. 3 is an electrical schematic of the present invention which illustrates the manner in which a common power source provides power to a microprocessor or controller and to a plurality of loads corresponding to support devices and in which the power supplied to the plurality of support devices may be terminated by opening the common ground line for such support devices through the operation of a single electronic switch situated within the microprocessor. 
     This and additional embodiments of the invention may now be better understood by referring to the following detailed description of the invention wherein the illustrated embodiment is described. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Throughout this description, a preferred embodiment and the examples shown should be considered as exemplars, rather than limitations on the apparatus and methods of the present invention. 
     Referring now to FIGS. 1-3, there is shown an incentive spirometer  100  having a volume chamber portion  50 , carrying a movable piston  53  within, and a goal-recording counter (GRC) which embodies the present invention. The volume chamber portion  50  provides a predetermined volume against which a patient&#39;s respiratory system is exercised for a determinable volumetric capacity to obtain the benefits of respiratory therapy. The GRC  60  is readily attachable and removable from the spirometer  100 , and informs a patient as to the number of times a predetermined breathing exercise, a proper event, has been properly performed. A monitoring portion  80  provides a visual display to the patient for determining the correct flow rate of inspiratory air to be applied by the patient&#39;s respiratory system during therapy, and in cooperation with the GRC  60  and volume chamber portion  50 , permits the patient to determine the quality of inspiratory air which has been drawn into the patient&#39;s lungs at the desired correct flow rate. For further details of the incentive spirometer illustrated, reference is had to co-pending application, Ser. No. 09/009,338, filed Jan. 20, 1998 in the name of Douglas M. Crumb, et al, the disclosure of which is incorporated herein by reference. 
     The volume chamber portion  50  of the incentive spirometer  100  includes a chamber  51  of a predetermined volume in which the piston  53  is carried. An air channel (not shown) forms a fluid connection between an inspiratory air inlet port  81  through which a patient draws inspiratory air, and the top (not shown) of the volume chamber  51 . In this manner, when a patient draws inspiratory air, the piston  53  is drawn upwardly. If a patient is drawing inspiratory air at the desired target flow rate as shown by an indicator  85 , the volume of air drawn into the patient&#39;s respiratory system can be determined by observing the calibrations  56  marked on the chamber  51 . 
     The GRC is attached to a portion of the chamber  51  by means of a removable mounting bracket  61 , which releasably connects the GRC  60  to the chamber  51 . An indicator  62 , formed on a portion of the mounting bracket  61 , is positioned at a preselected one of the volume calibration marks  56  which corresponds to the volume of air which is desired to be drawn into the patient&#39;s lungs when using the device. A count of the number of occasions upon which a patient draws the desired volume of air into the lungs, a proper event, is visually displayed on a display panel  63  of the GRC. When the patient inhales a sufficient volume of air to actuate the GRC, a lamp or light emitting diode (LED)  65  is flashed for a predetermined period of time “coaching” the patient to hold their breath during the time that the LED is illuminated. The manner in which the GRC  60  is actuated to record the number of occurrences in which a patient has successfully performed the proper event, the desired breathing exercise, and the manner in which the LED  65  is flashed to coach the patient in the proper performance of the exercise, is described in detail hereinafter with reference to FIGS. 2 and 3, and in co-pending application Improved Incentive Spirometer, Ser. No. 09/382,608, filed in the names of Lawrence A. Weinstein, et al, which is incorporated herein by reference. 
     The GRC  60  includes an infra-red emitter/detector  67 , comprising an IR emitter  67   a  and an IR detector  67   b,  such as a Sharp Model No. GP2S40, which is carried at the back side of the GRC  60  to determine the presence of the piston  53  being raised to the position of the indicator  62  in the volume chamber  51 . The IR emitter/detector  67  is coupled into the electrical circuit illustrated in FIG. 3 so that the GRC will record only the movement of the piston  53  within the volume chamber  51  to the proper position as set at indicator  62 , without being falsely triggered by other occurrences such as electrical noise or spurious IR signals. To this end, when a patient withdraws inspiratory air from the volume chamber  51 , the piston  53  carried there within will rise. When the patient has withdrawn a sufficient amount of inspiratory air to raise the piston  53  to the desired level, marked by the indicator  62 , the piston  53  will reflect the IR signal emitted from the emitter portion  67   a  into the detector portion  67   b  of the IR emitter/detector  67 . Upon verification of the presence of the piston  53 , the electrical circuit illustrated in FIGS. 2 and 3 will cause a display  63  to be stepped incrementally to show that the desired goal has been obtained by the patient. At the same time, the coaching lamp or LED  65  will flash intermittently for a predetermined time period, preferably six seconds, to “coach” the patient to hold their breath until the light is extinguished. In this manner, the patient is informed that the desired goal has been obtained and maintained for the correct period of time. 
     Referring now to the logic block diagram or flow chart of FIG. 2, the operation of the GRC  60  will be described in more detail. A preferred embodiment of the electrical circuit of this invention which is incorporated into the GRC  60  is illustrated in FIG.  3 . Initially, a power source such as 3-volt coin type battery  201 , commonly available as a CR 2 032, is connected to a high-performance, four-bit microprocessor or micro controller  200 , such as Model W741C250, available from Windbon Electronics Corporation America, 2727 North First Street, San Jose, Calif. 95134. To operate the GRC in the manner desired, and as illustrated in the preferred embodiment of FIG. 3, power is supplied to the microprocessor  200  at all times. However, during some operation of the GRC  60 , the “sleep” mode, it is desirable that power be supplied only to the microprocessor  200 , and not to the supporting devices such as a liquid crystal display (LCD) array  210  through which a number appears on the display panel  63  of the GRC, the light emitting diode (LED) indicator circuit  205  which includes the “coaching” lamp or LED  65 , and the infra-red detector circuit  67 , supporting devices used in the operation of the GRC. By shutting down all of the supporting devices and maintaining power to only the microprocessor  200  during a particular operational mode, the “sleep” mode, the battery  201  is conserved by reducing the current consumption to near zero. 
     When power is supplied to the GRC  60  by depressing an on/reset button  64 , the GRC will have been in a “sleep” mode, wherein power is being supplied to the microprocessor  200  only, and not to the surrounding support devices. In the “sleep” mode, the GRC retains the count of the previously completed exercises, or proper events. Depression of the on/reset button  64  will either “awaken” the GRC from the “sleep” mode to retain the count of the previously completed exercises, or will reset the GRC to display a “0” in the display window  63  to indicate that the GRC is in condition to record a new cycle of operation beginning with “0” and sequentially recording the number of successfully completed exercises from that point. 
     If the on/reset button  64  is depressed for more than three seconds, the GRC  60  will awaken and the input to the LCD array  210  will display a “0” to indicate that the GRC is in condition to record a new cycle of operation beginning with the numeral “0” appearing in the window  63 . If the on/reset button  64  is depressed for less than three seconds, the GRC  60  will awaken and the LCD array is energized to display in the display window  63  the retained count of how many times a patient has successfully completed an exercise since the last resetting of the GRC to “0”. Depression of the on/reset button  64  actuates a key press counter or reset shut down timer circuit within the microcontroller  200  to energize a timing circuit so that after a period of time the GRC will again be placed in a “sleep” mode, in the event that the piston  53  is not elevated by a patient into the predetermined position within the time period set by this shut down counter/timer. If the shut down timer has completed its count down without receiving a proper signal corresponding to the occurrence of a proper event, the elevation of the piston  53  by a patient into the predetermined position, the shut down timer will shut off the power to the surrounding support devices by opening a common path to ground for all these devices, thereby power will be supplied only to the microcontroller  200  placing the GRC again in the “sleep” mode. 
     When the on/reset button  64  has been depressed, the GRC is placed in condition to determine if a proper event signal has been received. When a proper event signal is received by the detector  67   b,  the LED indicator circuit  205  will be energized flashing the “coaching” LED  65  and activating an increment counter  63  so that the patient will hold the inhalation for a predetermined time period, preferably six seconds, during which time the LED  65  will remain flashing. At this time, the infra-red detector  67   b  will be disabled, and an internal shut down timer energized. If the shut down timer expires before a proper event signal has been received to reset the shut down timer, the microcontroller  200  will place the GRC in the “sleep” mode, thereby terminating power to all of the support devices such as the LCD array  210 , the LED “coaching” circuit  205  and the infra-red detector circuit  67  by opening the system ground RE 1  through the microcontroller  200 . Power from the battery  201  will be maintained only to the microcontroller  200  without maintaining the surrounding support devices to reduce the current consumption or drain on the battery  201  to nearly zero. 
     While this invention has been described in the specification and illustrated in the drawings which reference to a preferred embodiment, the structure of which has been disclosed herein, it will be understood by those skilled in the art to which this invention pertains that various changes maybe made, and equivalents maybe substituted for elements of the invention without departing from the scope of the claims. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed in the specification and shown in the drawings as the best mode presently known by the inventors for carrying out this invention, nor confined to the details set forth, but that the invention will include all embodiments, modifications and changes as may come within the scope of the following claims.