Abstract:
A back-up power supply for supplying operational power to a barrier movement apparatus when a mains supply of power is not present, including an enabling circuitry responsive to transmitted security codes for connecting operational power from the back-up power supply to the barrier movement apparatus. The back-up power supply includes a mains power input; a storage apparatus for storing power from the mains supply; converting apparatus for converting power stored by the storage apparatus into substitute mains power; and a control apparatus responsive to user generated request signals for enabling the converting apparatus to convert stored power into substitute mains power for use by the equipment. In accordance with another aspect of the invention, when a controller of a barrier movement apparatus identifies that a power reduction by a substitute power supply was caused by the barrier striking an obstruction, the controller directs the opening of the barrier, away from the obstruction when power is returned.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to backup power supplies and more particularly to the use of such with intermittently powered equipment. 
     Backup power supplies, sometimes called uninterruptable power supplies, are used to provide operational electrical power to equipment in times that the normal commercial or mains power system is not functioning. Backup power supplies generally comprise energy storage apparatus, such as batteries, connected to be charged from a mains power supply such as the 60 HZ, 120V power prevalent in the U.S. A power switching part of the backup power supply also connects the mains power directly to the equipment to be used. When a mains power failure occurs a conversion or invertor portion of the power supply is enabled to produce mains power e.g., 60 HZ, 120V from the stored power and the substitute power from the conversion portion is connected via the power switching part to the equipment to be powered. In this way the equipment can be powered during a mains power outage until the power stored by the backup power supply is used up or mains power is restored. 
     The power conversion apparatus of a backup power supply may consist of semiconductor switching circuitry connected to an input of a transformer. When the convertor is enabled due to mains power outage, an oscillator of predetermined frequency begins to drive the semiconductor switches to produce current pulses in the transformer. The equipment connected to the transformer output then has a continuing source of power for operation even though the mains power has stopped. The operations of the oscillator and semiconductor switches consume a significant amount of power from the power storage device whether or not the connected equipment requires power. Thus, the operation of the power converter is a backup power supply will consume significant stored power shortening the time that backup power is available, whether or not the equipment to be powered is actually taking power from the power supply. Such inefficiency is particularly problematic when the equipment to be powered is infrequently powered. 
     The use of backup power supply for example, with a barrier movement system, such as a garage door operator, provides advantages of barrier movement during power outage however, given the infrequent need for power the inefficiencies of the power convertor can needlessly shorten the period during which substitute power is available. 
     Additionally, backup power supplies frequently include protection circuitry which monitors the output power (current) of the supply and reduces the output power to prevent sustained overload. Such power reduction may involve reduction of output voltage or the elimination of one or more oscillator cycles to eliminate one or more current pulses to the output of the transformer. These steps at output power reduction may be responded to by the load as a power shutoff. When the equipment being powered includes an intelligent controller, such as a microprocessor, the controller may interpret the power reduction as a shut down and “forget” action being performed. This could create a problem when the power supply is used with a barrier movement apparatus and a power reduction by the power supply is initiated by an increased power demand upon the barrier striking an unexpected obstruction. When power is again restored, after the controller has lost knowledge of its prior activity, the barrier could be moved in a manner harmful to the barrier or the obstruction. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention a substitute power supply includes portions which are not enabled by a cessation of mains power until a user generated need for power is received. 
     In accordance with another aspect of the invention, when a controller of a barrier movement apparatus identifies that a power reduction by a substitute power supply was caused by the barrier striking an obstruction, the controller directs the opening of the barrier, away from the obstruction when power is returned. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a system including a backup power supply in conjunction with a barrier movement system; 
     FIG. 2 is a block diagram of a combined system in which the backup power supply includes a security code receiver; 
     FIG. 3 is a block diagram of a combined system in which power generation for the barrier movement controller is regulated by a power demand sensing circuit; and 
     FIG. 4 is a block diagram of a barrier movement controller. 
    
    
     DESCRIPTION 
     FIG. 1 is a block diagram of a combined system in which a backup power supply or uninterruptable power system  11  is connected to provide operating power to a barrier movement control  12 . Barrier movement control  12  may, for example, be a garage door opening system of the type described in U.S. Pat. No. 6,025,785. 
     Backup power supply  11  is connected, at an input port  13 , to a mains voltage supply which provides, for example, 120V at 60 HZ, the normal U.S. electrical power. A battery charger circuit  15  of conventional design is connected to the mains voltage and charges a battery  17  which will be the source of power during interruption of the mains voltage. The mains voltage is connected via a line active detector  19  and conductors  20  to a power switching unit  21 . The power switching unit is of conventional design and includes switching circuitry for connecting either the mains voltage supplied on conductors  20  or substitute mains voltage on conductors  22  to barrier movement controller  12 . The substitute mains voltage is supplied to conductors  22  by an invertor  23  which is connected to receive power from battery  17  and has access to the power stored thereby. Invertor  23  may also be of conventional design which generally includes an oscillator operating at a predetermined frequency and driven circuitry for switching battery power through a transformer the output of which is the substitute mains voltage on conductors  22 . 
     During normal operation, when mains voltage is present at input  13 , power switching unit  21  is controlled to connect the voltage from input  13  to the barrier movement controller  12 . Alternatively, when line active detector  19  senses an interruption of mains voltage at terminal  13  a signal is sent to an enable circuit  25  and power switch  21  is controlled to connect substitute mains power, when present, from invertor  23  and conductors  22  to barrier movement control  12 . By operation discussed below, no such substitute power is present until additional signals are provided to the enable circuit  25 . In the present embodiment such additional signals are generated by the barrier movement control  12 . Barrier movement controller  12  responds to user requests by opening and closing a barrier such as a garage door. In the embodiment of FIG. 1, user requests are directed to the barrier movement control  12  by a portable rf transmitter  27  and a wired wall control unit  29 . As is described in detail in the aforementioned U.S. Pat. No. 6,025,785, a user can press a button  31  on transmitter  27  to cause a security code to be rf transmitted. The barrier movement control  12 , which is shown in block diagram form in FIG. 4, includes an antenna  35  which is connected to an rf receiver  37  which detects received rf security codes and transmits the security code to a control unit  39 . Control unit  39 , which may include a programmed microprocessor is connected to a memory  41  for storing representations of previously learned security codes. Control unit  39  compares received security codes with stored security codes and when a proper correlation is present the barrier mover  43  is enabled to move a barrier (not shown). The barrier mover  43  may include an electrical motor in the ½ horsepower range and accordingly, requires significant mains power from the supply connected to conductor  24 . The user may also request movement of the barrier by pressing a wall switch  29  which is connected to control unit  39 . When a wall switch  29  signal is detected, control unit  39  directs barrier mover  43  to move the barrier. The barrier movement control  12  also includes a power supply  47  which receives mains power from conductor  24  and converts the power so received into appropriate power for receiver  37 , control unit  39 , and memory  41 . Advantageously power supply  47  may include a batter backup so that functions can continue by the receiver  37 , control unit  39  and memory  41  during periods that mains power is not present. As will be discussed below, such batter backup is not required. 
     When mains power at input  13  has ceased, all substitute mains power to control and run the system is drawn from battery  17 . The present apparatus includes arrangements for intelligently enabling and disabling the invertor  23  to provide substitute power when needed in response to a user request. When a user generates an appropriate request signal from transmitter  27  or wall control  29  at a time when mains power is not present the invertor  23  is enabled to provide the necessary substitute mains power to barrier movement control  12 . 
     When no mains voltage is present at input  13  line detector  19  sends a signal indicating such to enable circuit  25 . In the present embodiment this primes the enable circuit  25  to send an enable signal to invertor  23 , but no such enable signal is in fact sent. When barrier movement control  12  receives a user request from transmitter  27  or wall control  29  control unit  39  validates the request as needed and sends a power enable signal on conductor  45  to enable circuit  25  of the substitute power supply  11 . Enable circuit  25  responds to the loss of power signal from line active detector  19  and the power enable signal on conductor  45  by sending an enable signal on conductor  27  to power invertor  23 . As discussed above, power invertor  23  responds to the enable signal by generating the substitute mains power on conductor  22 . In order to further conserve power lost due to unneeded operation of the invertor  23  a timer  49  is included in the system to remove the invertor enable signal on conductor  27 . As shown in FIG. 1 timer  49  is connected to enable circuit  25  and begins timing at the beginning of the enable signal on conductor  27 . When the timer times out, at for example 20 seconds, the invertor enable signal on conductor  27  is inhibited and will not be regenerated until a subsequent request is received from barrier movement control  12 . It should be mentioned that s separate timing circuit is shown in the figures of this application, however, the timer may also be implemented by software controlling the operation of the substitute power supply  11 . 
     FIG. 2 is a block diagram of another embodiment in which the substitute power supply  11  includes a radio receiver and code check circuit  51  which can be used to enable the invertor. Radio receiver  51  includes a microprocessor and memory to control the security code reception and validation process. A learn button  53  is included with radio receiver  51  which, when pressed, initiates a code learning sequence in which a code received from a transmitter  27  will be stored in the memory of the radio circuitry. Such code learning operation is known in the circuitry. After one or more codes have been learned by the receiver  51  the operational mode is entered in which received security codes are compared to stored codes and the invertor  23  will be enabled by a signal on conductor  27  when a received code corresponds to a stored code. 
     The codes stored in receiver may be the same as the codes stored in the barrier movement control  12  or they may be different. When the same code is stored in both, a single transmission from transmitter  27  will activate both barrier movement and the power needed for moving the barrier. When the same codes are to be used in both the substitute power supply  11  and barrier movement control  12  they can be individually taught to each. Also the embodiment of FIG. 2 includes a data communications link  59  which permits data communication between the receiver  51  and control unit  39 . The security codes to be stored by receiver  51  may be downloaded from the memory  41  of barrier movement control  12  via the data link  59 . In this way a synchronized set of codes can be present in the memories of both units. 
     The embodiment of FIG. 2 can also be used with different codes being stored in the memories of the substitute power supply and the barrier movement control  12 . For example, a code corresponding to button  33  of transmitter  27  could be taught to receiver  51  and a code corresponding to button could be taught to the barrier movement control  12 . When the barrier is to be moved, button  33  is first pressed to which substitute power supply  11  responds by supplying substitute mains power to the barrier movement control  12 . The button  31  is then pressed and the barrier movement control will be enabled to use the substitute power from the substitute power supply to move the barrier. Enabling the power supply first would allow the use of the barrier movement control  12  when no battery backup is available for the power supply of the barrier movement control. 
     In the preceding embodiment the invertor  23  was enabled by direct signaling from the user from the wall switch  29  or transmitter  27 . FIG. 3 represents an embodiment in which the substitute power supply is enabled in response to indirect requests from the user. The apparatus of FIG. 3 includes power demand sensing circuit  61  which senses the input power demand of the barrier movement control  12 . When no mains power is present at input  13  power demand sensing circuit detects the demand for power by the barrier movement control  12  and generates a power control signal on a conductor  63  representing the power demanded. During periods when no request for barrier movement is received the power control signal represents low power which is just enough to power the control unit  39 , receiver  37  and memory  41  of the barrier movement control  12 . Little power from battery  17  is lost due to inefficiencies when the invertor operates in the low power mode. When the barrier movement control receives an rf or hard wired request to move the barrier the demand for high power is detected by the power demand sensing circuit  61  and the power control signal on conductor  63  is changed to represent the new high power demand. Invertor  25  responds to the high power request signal by generating full output power on conductors  22  which is available for use to move the barrier. The timer  49  returns the invertor to low power output after the passage of a predetermined amount of time which might be, for example, 20 seconds. As before, the time out of timer  49  should permit sufficient time to fully open or fully close the barrier. 
     Substitute power supplies generally include over current or over power sensing capability which protects the power supply. When too much power demand is sensed the over power sensing capability reduces the power output by reducing output voltage or by omitting several voltage cycles (pulses) from the e.g., 60 HZ, output power. Such over power demand might be detected by the substitute power supply when a moving barrier has encountered an obstruction and is pushing against it. Should the power supply shut down at this point the barrier reversing capability which is standard on many barrier movement controls, might not be enabled. To protect against such failure to reverse, the embodiment of FIG. 3 includes methods and apparatus which sense power shut down by the power supply and assure that any re-powering of the barrier movement control will result in a reversing of the barrier. 
     FIG. 3 includes an under voltage detector  65  which detects a reduced output voltage or missing cycles by the substitute power supply. When either of these conditions is sensed, a signal is sent to barrier movement control to identify the condition. If the condition occurs while the barrier is being moved an “immediate reverse” condition is written into non-volatile storage of the barrier operator. Upon power up by the power supply, barrier movement control  12  begins operation, reads the stored “immediate reverse” condition, and controls the barrier movement control to reverse the direction of door travel to free whatever obstruction was encountered. Given that the voltage reduction or cycle elimination is brief, as is normally the situation, such immediate obstruction reversal can be completed much as the barrier operator would have done without the power outage. 
     While there has been illustrated and described a particular embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention. By way of example, the transmitter and receivers of the disclosed embodiment are controlled by programmed microcontrollers. The controllers could be implemented as application specific integrated circuits within the scope of the present invention.