Abstract:
A lamp string controlling device includes a power supply circuit constituted by a transformer and a rectification circuit for converting an alternate current into a direct current. A harmonic oscillation circuit is connected between the transformer and the rectification circuit for eliminating noise and electromagnetic interference. A single chip based control circuit is connected between the power supply circuit and a driver circuit which drives a lamp string. The control circuit controls the lighting status of the lamp string between a full load condition and a non-full load condition in a variety of styles. A timing circuit having a time constant is coupled to the control circuit for switching the lamp string from a full load condition to the non-full load condition after a time period determined by the time constant thereof whereby overall power consumption of the lamp string may be lowered down and thus a small-sized transformer suffices for the operation of the lamp string. Therefore a compact lamp string controlling device may be formed by combining the power supply circuit and the control circuit together. A manual switch and a remote control module may be coupled to the control circuit for manual and remote control.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a lamp string controlling device, and in particular to a lamp string controlling device capable to controlling a lamp string composed of a multiplicity of loops. 
     BACKGROUND OF THE INVENTION 
     Lamp strings have been widely used in all kinds of celebrations and festivals. The lamp strings are attached to for example trees along a street. The lamp strings are powered by electricity and controlled by a controlling device to change the lighting status of the lamps. 
     Conventionally, the lamp strings are usually set to the full load condition without any time limits. Thus, a great consumption of power is encountered. Furthermore, to support such a great power consumption, a large-sized transformer is required. Therefore, the overall size of a lamp string controlling device may have a large size that is not suitable for outdoor use. 
     Furthermore, due to the large size of the power supply circuit, it is common that the power supply circuit and a control circuit are separated from each other with wires connected therebetween. This increases the cost and space requirement in installing the lamp string. 
     In addition, the lamp string controlling device is easily subject to electromagnetic interference. A high frequency filter may be connected between the power supply circuit and the control circuit to overcome the electromagnetic interference. The filter, however, increases the size and the cost of the lamp string controlling device. 
     Besides, the conventional control circuit may only control the lighting status of the lamp string in a limited ways. This is not consumer appealing. 
     It is thus desirable to have a lamp string controlling device that overcomes the above problems. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a lamp string controlling device comprising a timing circuit for switching the lamp string from a full load condition to a non-full load condition after a predetermined time period for lowering down power consumption and reducing the required size of the transformer thereby allowing the power supply circuit and a control circuit to be combined together. 
     Another object of the present invention is to provide a lamp string controlling device in which a power supply circuit and a control circuit are combined together whereby wire connection therebetween is shortened and electromagnetic interference is reduced. 
     A further object of the present invention is to provide a lamp string controlling device comprising a control circuit capable to control the lighting status of lamp strings connected thereto in a variety of styles. 
     A further object of the present invention is to provide a lamp string controlling device comprising a manual switch and/or a remote control module for manual or remote control of the lamp string controlling device. 
     To achieve the above objects, in accordance with the present invention, there is provided a lamp string controlling device comprising a power supply circuit constituted by a transformer and a rectification circuit for converting an alternate current into a direct current. A harmonic oscillation circuit is connected between the transformer and the rectification circuit for eliminating noise and electromagnetic interference. A single chip based control circuit is connected between the power supply circuit and a driver circuit which drives a lamp string. The control circuit controls the lighting status of the lamp string between a full load condition and a non-full load condition in a variety of styles. A timing circuit having a time constant is coupled to the control circuit for switching the lamp string from a full load condition to the non-full load condition after a time period determined by the time constant thereof whereby overall power consumption of the lamp string may be lowered down and thus a small-sized transformer suffices for the operation of the lamp string. Therefore a compact lamp string controlling device may be formed by combining the power supply circuit and the control circuit together. A manual switch and a remote control module may be coupled to the control circuit for manual and remote control. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof, with reference to the accompanying drawings, in which: 
     FIG. 1 is a system block diagram of a lamp string controlling device in accordance with a first embodiment of the present invention; 
     FIG. 2 is a circuit diagram of the lamp string controlling device of the first embodiment of the present invention; 
     FIG. 3 is a perspective view of the lamp string controlling device of the first embodiment of the present invention; 
     FIG. 4 is a system block diagram of a lamp string controlling device accordance with a second embodiment of the present invention; 
     FIG. 5 is a circuit diagram of the lamp string controlling device of the second embodiment of the present invention; and 
     FIG. 6 is a perspective view of the lamp string controlling device of the second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawings and in particular to FIG. 1, wherein a lamp string controlling device constructed in accordance with a first embodiment the present invention, generally designated by reference numeral  100 , is shown, the lamp string controlling device  100  comprises a power supply circuit  10  receiving an alternate current from for example a wall outlet of an electric main (not shown) and converting the alternate current into a direct current for powering the lamp string controlling device  100 . The power supply circuit  10  comprises a transformer  11 , a harmonic oscillation circuit  12  and a rectification circuit  13 . 
     The transformer  11  converts the alternate current having a first (high) voltage from the electric main into an alternate current of a second (low) voltage lower than the first voltage. The harmonic oscillation circuit  12  is coupled between a secondary winding of the transformer  11  and the rectification circuit  13  for eliminating electromagnetic interference and suppressing noise whereby the rectification circuit  13  which is to convert the alternate current of second voltage into a direct current may supply a stable and not-interfered direct current to the lamp string controlling device  100 . 
     A control circuit  20  controls the operation and lighting status of a lamp string  40  electrically connected to the lamp string controlling device  100 , including the ON/OFF status, the brightness, cycling, alternate sparkling. The control circuit  20  may include automatic control, manual control and remote control. A driver circuit  30  is coupled between the control circuit  20  and the lamp string  40  whereby the lamp string  40  is driven by the driver circuit  30  controlled by the control circuit  20 . The lamp string  40  may comprise a single loop of lamp string. Preferably, the lamp string  40  comprises multiple loops, such as four loops in the embodiment illustrated. 
     A timing circuit  50  is coupled to the control circuit  20  for controlling the operation thereof. For example, when the lamp string  40  is in a full load condition, namely all the lamps thereof being lightened, the timing circuit  50  starts a timing operation and once a predetermined period of time is reached, a switching signal generated by the timing circuit  50  is applied to the control circuit  20  to cause the control circuit  20  to change the lamp string  40  to a non-full load condition. This is advantageous in that the rating power value (volt-ampere or watt value) of the transformer  11  may be lowered down but still sufficient to maintain the operation of the lamp string  40 . For example, if the full load condition of the lamp string  40  requires a power of  36  watts, then the transformer  11  may be selected to be of a rating power value of  20  watts. This helps to reduce the size of the transformer  11  and may thus allow the power supply circuit  10 , the control circuit  20 , the driver circuit  30  and the timing circuit  50  to be combined together as a single unit. 
     The transformer  11  may be a high frequency transformer or a ring transformer which further reduces the size of the lamp string controlling device  100 . 
     Also referring to FIG. 2, which shows a detailed circuit diagram of the lamp string controlling device  100 , the harmonic oscillation circuit  12  of the power supply circuit  10  comprises a secondary winding L of the transformer  11  and a capacitor C 1  for eliminating high frequency electromagnetic interference. The rectification circuit comprises a bridge rectifier circuit B having output terminals B 1 , B 2  respectively representing positive and negative poles for supplying a stable direct current. 
     In the embodiment illustrated in FIG. 2, the control circuit  20  is embodied as a single chip integrated circuit. Power terminals VCC and VDD of the control circuit  20  are connected to the output terminals B 1 , B 2  of the bridge rectifier circuit B of the power supply circuit  10  to receive power therefrom. The control circuit  20  comprises a plurality of output terminals T 1 , T 2 , T 3 , T 4  for supplying display control signals to the driver circuit  30  and a switch control terminal CS for receiving the switching signal from the timing circuit  50 . 
     Furthermore, a manual switch SI and a radio receiver (remote control) module S 2  are also connected to the switch control terminal CS for manual control and remote control of the control circuit  20 . 
     The driver circuit  30  comprises thyristor elements G 1 , G 2 , G 3 , G 4  respectively connected to the output terminals T 1 , T 2 , T 3 , T 4  of the control circuit  20  for controlling the triggering phase in order to individually controlling the ON/OFF status of each loop of the lamp string  40 . It is noted that the lamp string  40  comprises four loops respectively associated with the four thyristor elements G 1 , G 2 , G 3 , G 4 . 
     Example of the thyristor elements G 1 , G 2 , G 3 , G 4  may comprise silicon controlled rectifier having a gate connected to the output terminal of the control circuit  20 . 
     In the embodiment illustrated in FIG. 3, the timing circuit  50  comprises a transistor Q 1  resistors R 4 , R 5  and capacitors C 3 , C 4 . The resistors R 4 , R 5  and the capacitor C 3  determine the time constant of the timing circuit  50 . In a preferred embodiment of the present invention, the time constant is set between  10  and  30  second. This time constant corresponds to a time period in which the transformer  11  and the rectification circuit  13  are allowed to be overloaded when the lamp string  40  is in full load condition. In other words, the transformer  11  may not be damaged due to overload within such a time period. The resistor R 4  is also connected to the output terminal T 1  of the control circuit  20  for detecting a full load condition of the lamp string  40 . As mentioned above, when a full load condition is detected, the timing circuit  50  is actuated. Once the timing circuit  50  reaches a predetermined time period determined by the time constant, the transistor Q 1  having a collector connected to the switching control terminal CS of the control circuit  20  generates and applies the switching signal to the switching control terminal CS of the control circuit  20  for switching the output terminals T 1 , T 2 , T 3 , T 4  to a non-full load condition, namely the lamp string  40  is not fully lightened thereby lowering down the power consumption of the lamp string  40  back to the rating power value of the transformer  11 . 
     Also referring to FIG. 3, a perspective view of the lamp string controlling device  100  in accordance with a first embodiment of the present invention is shown. In accordance with the present invention, the size of the transformer  11  may be reduced by using the timing circuit  50  to control the control circuit  20  for limiting the full load condition of the lamp string  40 . This allows the power supply circuit  10 , the control circuit  20 , the driver circuit  30  and the timing circuit  50  to be housed in a single common casing  200 . Two contact blades  210 ,  220  extend beyond the casing  200  for connection with an electric main. Preferably, the contact blades  210 ,  220  are arranged in a style similar to a regular electric plug. 
     The manual switch S 1  may be mounted on the casing  200  for user&#39;s access and the remote control module S 2  may be arranged inside the casing  200  for controlling the control circuit  20 . 
     In the embodiment illustrated in FIG. 3, the lamp string  40  comprises four loops, namely X 1 , X 2 , X 3 , X 4  which are arranged to be cyclic and alternate with each other. It is noted that the lamp loops X 1 , X 2 , X 3 , X 4  may be arranged in any desired fashion. The lamp loops X 1 , X 2 , X 3 , X 4  are respectively connected to the output terminals T 1 , T 2 , T 3 , T 4  of the control circuit  20 . 
     The control circuit  20  may be operated in a variety of different ways. An example of a eight-phase control is shown as follows: 
     (1) automatically and cyclically demonstrating the following phases (2)-(8). 
     (2) alternately decreasing/increasing brightness of the loops X 1 -X 4  of the lamp string  40  to show a wavy-like fashion. 
     (3) sequentially and cyclically lightening the four loops X 1 -X 4  of the lamp string  40 . 
     (4) the brightness of each loop X 1 , X 2 , X 3 , X 4  of the lamp string  40  sequentially decreased and then increased. 
     (5) the loops X 1 -X 4  of the lamp string  40  being randomly lightened. 
     (6) the brightness of the loops X 1 -X 4  gradually decreased and then suddenly changed to full brightness simultaneously. 
     (7) the loops X 1 -X 4  irregularly sparkling 
     (8) the loops X 1 -X 4  in full brightness for 10-30 seconds and then switched to phase (1). 
     The above sequence is performed on the basis of automatic control. In other words, the manual switch S 1  and the remote control module S 2  are not actuated. The manual switch S 1  or the remote control module S 2  may be used to interrupt any one of the above eight phases. If desired, a circuit associated with the manual switch S 1  and the remote control module S 2  may be incorporated so that each time the manual switch S 1  is turned off and then turned on or the remote control module S 2  is actuated, the above operation sequence may be shifted to a next phase. For example, a user may directly jump to phase five by actuating the remote control module S 2  five times. The phases may run cyclically so that when a user actuates the remote control module S 2  nine times, the operation is switched back to the first phase. 
     It is noted that in the above operation process, the lamp string  40  may only be overloaded in phases  6  and  8 , while in other phases, the lamp string  40  is not overloaded. 
     Referring to FIGS. 4-5, a second embodiment of the lamp string controlling device  100  of the present invention is shown. The difference between the embodiment of FIGS. 1-3 and that of FIGS. 4-5 is that a voice circuit  60  and a speaker  70  are incorporated in the second embodiment of FIGS. 4-5 for providing voice/music playing function. 
     As shown in FIG. 5, the voice circuit  60  that is controlled by the control circuit  20  is connected to a voice signal output terminal P 1  of the control circuit  20 . The voice circuit  60  comprises transistors Q 2 , Q 3 , Q 4  forming an amplification circuit for driving the speaker  70  to play voice or music. 
     Also referring to FIG. 6, a perspective view of the lamp string controlling device  100  of second embodiment is shown. As discussed above, the size of the transformer  11  may be reduced due to the use of the timing circuit  50  associated with the control circuit  20  for limiting the full load condition of the lamp string  40 . Thus, the power supply circuit  10 , the control circuit  20 , the driver circuit  30 , the timing circuit  50 , the voice circuit  60  and the speaker  70  may be housed in a single common casing  300 . Two contact blades  310 ,  320 , similar to the contact blade  210 ,  220  of the first embodiment shown in FIGS. 1-3, extend beyond the casing  300  for connection with an electric main. The manual switch SI and the remote control module S 2  are similar to the counterpart of the first embodiment whereby no further description is needed. The arrangement of the loops X 1 -X 4  of the lamp string  40  in the second embodiment is similar to that of the first embodiment. 
     The control circuit  20  of the lamp string controlling device  100  of the second embodiment may be operated in a variety of different ways. An example of a seven-phase control is shown as follows: 
     (1) the loops X 1 -X 4  of the lamp string  40  sparkling simultaneously. 
     (2) the loops X 1 -X 4  of the lamp string  40  sparkling alternately. 
     (3) the loops X 1 -X 4  of the lamp string  40  sequentially and cyclically lightened. 
     (4) the loops X 1 -X 4  of the lamp string  40  divided into two sets which sequentially and cyclically lightened. 
     (5) repeating phases (1)-(4) with music played simultaneously. 
     (6) repeating phases (1)-(4) without music. 
     (7) changing the loops X 1 -X 4  of the lamp string  40  to full brightness for 10-30 seconds and then switched to phase (1). 
     The lamp string controlling device of the present invention as described above has the following advantages: 
     (1) the overall size is significantly reduced thereby suitable for outdoor operation. 
     (2) the power supply circuit and the control circuit are combined together and an oscillation circuit is incorporated in the power supply circuit thereby reducing noise of electromagnetic interference. 
     (3) the lightening sequence/fashion of the lamp string may be varied arbitrarily and music may be incorporated in the operation thereof. 
     (4) manual control and remote control are incorporated. 
     Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.