Abstract:
A power control circuit used in a vending machine having a bill accepter and vending main units controlled by the bill accepter is disclosed to include a pulse signal generator installed in the bill inlet of the bill accepter and adapted to generate a triggering signal upon insertion of a bill into the bill inlet of the bill accepter, a driver, and a trigger, which controls the driver to drive the bill accepter between the power-saving stand-by mode and the work mode subject to the presence of the pulse signal from the pulse signal generator.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a power control circuit for use in a vending machine and, more particularly, to such a power control circuit, which drives the bill accepter of the vending machine into the power-saving stand-by mode when the bill accepter receiving no bill. 
   2. Description of the Related Art 
   In public places, a variety of automatic vending machines may be installed to provide candy, ticket, changes, etc., when a coin or bill is dropped in. A big vending machine comprises a bill accepter and a number of vending main units. Conventional vending machines are commonly designed to consume city power supply directly. When installed, the bill accepter is constantly maintained turned on. Because the bill accepter is constantly maintained turned on, much electricity is consumed when the vending machine runs idle. 
   Therefore, it is desirable to provide a power control circuit for use in a vending machine, which eliminates the aforesaid drawbacks. 
   SUMMARY OF THE INVENTION 
   The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a power control circuit for use in a vending machine, which automatically turns the bill accepter from the working mode to the stand-by mode when vending machine receiving no bill, or from the stand-by mode to the working mode when the vending machine receiving a bill. According to one embodiment of the present invention, the power control circuit comprises a pulse signal generator installed in the bill inlet of the bill accepter of the vending machine and adapted to generate a triggering signal upon insertion of a bill into the bill inlet of the bill accepter, a driver, and a trigger, which controls the driver to drive the bill accepter between the power-saving stand-by mode and the work mode subject to the presence of the pulse signal from the pulse signal generator. According to an alternate form of the present invention, the power control circuit comprises a trigger adapted to generate a triggering signal, and a driver adapted to receive the triggering signal from the trigger. The driver connects power supply to the bill accepter when receiving the triggering signal from the trigger, or disconnects power supply from the bill accepter when receiving no signal from the trigger. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a circuit block diagram showing the system arrangement under the first trigger mode according to the present invention. 
       FIG. 2  is a circuit block diagram showing the system arrangement under the second trigger mode according to the present invention. 
       FIG. 3  is a circuit block diagram of the power control circuit according to the present invention. 
       FIG. 4  is an operation flow of the present invention when started (I). 
       FIG. 4A  is an operation flow of the present invention when started (II). 
       FIG. 5  is a stand-by mode operation flow chart according to the present invention. 
       FIG. 6  is a bill rejection mode operation flow chart according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 3 , a power control circuit  10  constructed according to the first trigger mode of the present invention is installed in a vending machine and electrically connected between the bill accepter  20  and vending main units  30  of the vending machine, comprising a pulse signal generator  13 , a trigger  11 , and a driver  12 . The pulse signal generator  13  is installed in the inlet of the bill accepter  20 . The PIN OUT of the trigger  11  is connected to the vending main units  30 . 
   After a predetermined length of time in which the inlet of the bill accepter  20  received no bill, the bill accepter  20  triggers a D-type flip-flop (U1)  111  to draw PIN6 from high potential to low potential, thereby causing PIN5 to be zeroed. At this time, a N-channel field effect transistor (Q2)  121  of the driver  12  is caused to turn off a P-channel field effect transistor (Q3)  122 , stopping main power supply from passing to the bill accepter  20 , and therefore the bill accepter  20  directly enters the power-saving stand-by mode and outputs an enable signal EN to a N-channel field effect transistor (Q1)  112  of the trigger  11  to keep PIN OUT in high potential, informing the vending main units  30  of the stand-by mode status of the bill accepter  20 . When entered the stand-by mode, an oscillation module  131  of the pulse signal generator  13  drives a LED (light emitting diode)  132  to emit light, which is ten received by a phototransistor  133  to hold Vpt in low potential, waiting for work mode. 
   When a bill entered the inlet of the bill accepter  20 , it blocks the light of the LED  132 , thereby causing RC (resistance-capacitance) to be charged to change Vpt from low potential to high potential and to further trigger PIN 1  of the D-type flip-flop (U1)  111  and change the status of PIN5 of the D-type flip-flop (U1)  111  from low potential to high potential. When PIN5 of the D-type flip-flop (U1)  111  changed to high potential, the N-channel field effect transistor (Q2)  121  is driven to turn on the P-channel field effect transistor (Q3)  122 , enabling main power supply to pass to the bill accepter  20 . At this time, the trigger  11  outputs an enable signal to drive the N-channel field effect transistor (Q1)  112 , causing PIN OUT to be changed from high potential to low potential. When PIN OUT changed to low potential, the trigger  11  gives a signal to the vending main units  30 , informing the vending main units  30  of the work mode status of the bill accepter  20 . 
     FIG. 2  is a circuit block diagram of the second trigger mode according to the present invention. The power control circuit  10  is electrically connected between a bill accepter  20  and a plurality of vending main units  30 , comprising a trigger  11 , and a driver  12 . 
   Referring to  FIGS. 2 and 3  again, when the vending main units  30  not triggered (the respective press-buttons are off), the bill accepter  20  is changed from the work mode to the stand-by mode. The flow of changing from the work mode to the stand-by mode is outlined hereinafter. The diode D detects the potential level of PIN OUT. When high potential of PIN OUT detected, PIN6 of the D-type flip-flop (U1)  111  of the trigger  11  is triggered by means of a low potential, causing PIN5 of the D-type flip-flop (U1)  111  of the trigger  11  to be changed from high potential to low potential. The low potential signal is then passed from PIN5 of the D-type flip-flop (U1)  111  of the trigger  11  through the N-channel field effect transistor (Q2)  121  to the P-channel field effect transistor (Q3)  122 , thereby causing the P-channel field effect transistor (Q3)  122  to stop main power supply from passing to the bill accepter  20 , and therefore the bill accepter  20  enters the power-saving stand-by mode. 
   When one vending main unit  30  is triggered (switched on), a pulse is sent through PIN OUT to trigger PIN1 of the D-type flip-flop (U1)  111  of the trigger  11 , thereby causing PIN5 of the D-type flip-flop (U1)  111  of the trigger  11  to be changed from low potential to high potential, which high potential is ten sent through the N-channel field effect transistor (Q2)  121  of the driver  12  to the P-channel field effect transistor (Q3)  122 , thereby causing the P-channel field effect transistor (Q3)  122  to be turned on to let main power supply pass to the bill accepter  20 , and therefore the bill accepter  20  enters the work mode. 
     FIGS. 4 and 4A  show the operation flows of the present invention. When the bill accepter started, it runs subject to the steps as follows:
       401  Power supply turned on;     402  System initialization;     403  Determine if the system functions normal or not? And then proceed to step  404  if positive, or step  409  if negative;     404  Determine if bill accepter has been jammed or not? And then proceed to step  405  if jammed, or step  407  if not jammed;     405  Send working messaging to vending main unit, and then proceed to step  406 ;     406  Enter troubleshooting mode (see  FIG. 6 );     407  Send working messaging to vending main unit, and then proceed to step  408 ;     408  Enter stand-by mode (see  FIG. 5 );     409  Determine whether vending main unit has been connected? And then proceed to step  412  if connected, or step  410  if not connected;     410  Determine if to change stand-by mode to work mode or not? And then proceed to step  412  is positive, or step  411  if negative;     411  Be ready to enter stand-by mode, and then proceed to step  409 ;     412  Wait for insertion of bill, and then proceed to step  413 ;     413  Determine whether there is any bill to be accepted? And then proceed to step  415  if positive, or step  414  if negative;     414  Be ready to enter power-saving mode, and the proceed to step  413 ;     415  Accept inserted bill, and the proceed to step  416 ;     416  Determine whether inserted bill has been delivered into position? And then proceed to step  418  from S 2  if positive, or step  417  if negative;     417  Enter bill rejection mode (see  FIG. 6 );     418  Determine whether vending main unit has been connected? And then proceed to step  419  if positive, or step  425  if negative;     419  Determine if vending main unit has been allowed to accept bill or not? And then proceed to step  420  if positive, or step  428  if negative;     420  Inform vending main unit of the value of bill, and then proceed to step  421 ;     421  Determine whether vending main unit has been informed to wait for transaction? And then proceed to step  422  if positive, or enter step  426  from S 3 ;     422  Determine whether vending main unit has informed to accept bill or not? And then proceed to step  423  if positive, or step  428  if negative;     423  Send bill to money box, and then proceed to step  424 ;     424  Inform vending main unit of completion of bill acceptance procedure, and then enter step  412  from S 1 ;     425  Determine whether waiting time is up? And then proceed to step  428  if positive, or step  418  if negative;     426  Determine whether to wait for the connection of vending main unit or not? And then enter step  421  from S 4  if positive, or proceed to step  427  if negative;     427  Determine whether communication time is over? And then proceed to step  428  if over, or enter step  421  from S 4  if not over;     428  Enter bill rejection mode (see  FIG. 6 ).   
     FIG. 5  illustrates the flow of the stand-by mod. When the bill accepter entering the stand-by mode, it runs subject to the steps as follows:
       501  Start stand-by mode;     502  Determine whether vending main unit has sent enable command or not? And then proceed to step  503  if positive, or step  505  if negative;     503  Determine whether vending main unit has stopped communication? And then proceed to step  504  if positive, or step  507  if negative;     504  Determine if communication ended? And then proceed to step  506  if communication ended, or step  507  if not;     505  Determine whether bill accepter has power-saving mode? And then proceed to step  506  if positive, or step  504  if negative;     506  Enter stand-by mode;     507  Leave from stand-by mode.   
   Referring to  FIG. 4 , which illustrates the operation flow of the present invention when the bill accepter started, and  FIG. 6 , which illustrates the operation flow of the bill rejection mode. When entered the bill rejection mode, it runs subject to the steps as follows:
       601  Start bill rejection mode;     602  Determine if bill has been rejected or not? And then enter step  412  from S 1 , or proceed to step  603 ;     603  Eliminate bill jam problem, and then proceed to step  604 ;     604  Determine whether bill is still jammed? And then proceed to step  605  if positive, or step  606  if negative;     605  Be ready to enter stand-by mode;     606  Determine if bill jam problem can be eliminated or not? And then proceed to step  605  if bill jam problem cannot be eliminated, or step  607  if bill jam problem can be eliminated;     607  Eliminate bill jam problem;     608  Determine whether bill rejection is done? And then enter step  412  from S 1  if positive, or proceed to step  606  if negative.   

   As indicated above, when the bill accepter  20  or one vending main unit  30  generated a trigger signal, the bill accepter  20  immediately returns from the stand-by mode to the work mode. When runs idle, the power control circuit  10  cuts off power supply from the bill accepter  20 , keeping the bill accepter  20  in the power-saving stand-by mode. 
   A prototype of power control circuit for use in a vending machine has been constructed with the features of the annexed drawings of  FIGS. 1˜6 . The power control circuit for use in a vending machine functions smoothly to provide all of the features discussed earlier. 
   Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.