Patent Publication Number: US-9900960-B1

Title: Dual color temperature-controlling system

Description:
The present invention is related to a color temperature-controlling system, particularly to a dual color temperature-controlling system. 
     BACKGROUND OF THE INVENTION 
     In lighting systems, having become an indispensable part in modern life, a variety of light sources are used for the enhancement of brightness in specific sites. Further, as technology advances, certain requirements for brightness, color temperature, light distribution pattern and etc., needed in each site, especially in sites involving personal safety are provided. Thus, there are strict requirements for street lights, vehicle lamps and so on. 
     A street light, such as “Street light led” disclosed in U. S. patent US20120106156, comprises a pole, a solid state light emitting device provided on the pole, and an optical element provided on the pole. A light is emitted from the solid state light emitting device. Moreover, a light distribution pattern complying with requirements may be produced from the light by the optical element and then emitted. 
     Only one single color temperature, however, is inherent in such a kind of street light. It is possibly not clear enough in general conditions, if warm color temperature is used. Nevertheless, it is clearer if cool color temperature is used, in comparison with warm color temperature, though the problem of poor visibility occurs because the cool light is apt to be reflected by water vapor in the rain or mist. Therefore, how to change color temperature of the light source according to the external environment is truly the topic with which the industry is confronted. 
     SUMMARY OF THE INVENTION 
     It is the main object of the present invention to solve the problem of incapability of changing color temperature according to the external environment. 
     For achieving the above object, the present invention provides a dual color temperature-controlling system mounted on a street light and electrically connected to a brightness controlling module of the street light. The dual color temperature-controlling system includes a power supply controlling module, a switching module, a first color temperature light emitting module, a second color temperature light emitting module and a comparing module. The switching module is electrically connected to the power supply controlling module. The first color temperature light emitting module and the second color temperature light emitting module are electrically connected to the switching module. The comparing module is electrically connected to the switching module and the brightness controlling module. A voltage-type operating signal sent from the brightness controlling module is received by the comparing module for comparison, and a switching signal is then sent from the comparing module to the switching module. The switching module is switched for lighting up the first color temperature light emitting module, or for lighting up the second color temperature light emitting module depending on the switching signal. 
     To sum up, the present invention is provided with features as follows: 
     1. Color temperature of the street light may be changed according to the external environment by switchingly lighting up the first color temperature light emitting module or the second color temperature light emitting module depending on the voltage-type operating signal, for the enhancement of safety of road occupant. 
     2. The voltage-type operating signal sent from the brightness controlling module originally provided in the street light is used directly for controlling the first color temperature light emitting module or the second color temperature light emitting module to be lighted up, without additional modules for sensing the external environment, so as to reduce the cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a function block diagram of a preferred embodiment of the present invention. 
         FIG. 2  is a circuit diagram of a preferred embodiment of the present invention. 
         FIG. 3  is a switching loop diagram of a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed description and technical content of the present invention will now be described in combination with drawings as follows. 
     Referring to  FIGS. 1 to 3 , the present invention is related to a dual color temperature-controlling system mounted on a street light and electrically connected to a brightness controlling module  1  of the street light. The brightness controlling module  1  is allowed for controlling the brightness of the street light depending on the external environment. Further, the dual color temperature-controlling system includes a power supply controlling module  10 , a switching module  20 , a first color temperature light emitting module  30 , a second color temperature light emitting module  40  and a comparing module  50 . The switching module  20  is electrically connected to the power supply controlling module  10 . The first color temperature light emitting module  30  and the second color temperature light emitting module  40  are electrically connected to the switching module  20 . The comparing module  50  is electrically connected to the switching module  20  and the brightness controlling module  1 . In this case, the first color temperature light emitting module  30  may be operated for high color temperature, while the second color temperature light emitting module  40  may be operated for low color temperature, but not limited thereto. 
     A voltage-type operating signal  2  is sent from the brightness controlling module  1 . After the voltage-type operating signal is received by the comparing module  50  for comparison, a switching signal is sent from the comparing module to the switching module  20 . The switching module  20  is switched for lighting up the first color temperature light emitting module  30 , or for lighting up the second color temperature light emitting module  40  depending on the switching signal, such that color temperature of the street light is changed according to the external environment, so as to enhance safety of road occupant. Moreover, the brightness controlling module  1  originally provided in the street light may be utilized for the modulation of color temperature without additional modules, so as to reduce the cost. 
     In this embodiment, the power supply controlling module  10  includes a first voltage source  11 , a second voltage source  12 , a first voltage stabilizer  13 , a first diode  14 , a second diode  15 , a first Zener diode  16 , a first capacitor  17   a , a second capacitor  17   b , a third capacitor  17   c , a first resistor  18 , and a voltage regulator  19 . The anode of the first diode  14  is electrically connected to the first voltage source  11 , and the cathode of the first diode  14  is electrically connected to the first resistor  18 . The first voltage stabilizer  13  is a transient voltage suppressor (abbreviated as TVS), two ends of which are electrically connected to the first voltage source  11  and grounded, respectively. The first capacitor  17   a  is electrically connected at two ends thereof to the anode of the first diode  14  and to the anode of the first Zener diode  16 , respectively. The anode of the second diode  15  is electrically connected to the second voltage source  12 , and the cathode of the second diode  15  is electrically connected to the first resistor  18 . The cathode of the first Zener diode  16  is electrically connected to the cathode of the second diode  15 . The second capacitor  17   b  is electrically connected at two ends thereof to the anode of the first Zener diode  16  and the cathode of the second diode  15 , respectively. The voltage input terminal of the voltage regulator  19  is electrically connected to the cathode of the second diode  15 , and the voltage output terminal of the voltage regulator  19  is electrically connected to the first color temperature light emitting module  30  and the second color temperature light emitting module  40 . The ground terminal of the voltage regulator  19  and the anode of the first Zener diode  16  are electrically connected to each other and grounded. The third capacitor  17   c  is electrically connected at two ends thereof to the second voltage source  12  and to the second capacitor  17   b , respectively. Further, in this embodiment, the voltage regulator  19  is produced by Texas Instruments, model no. LM2936HV. 
     Further, the comparing module  50  includes a second voltage stabilizer  51 , a second Zener diode  52 , a second resistor  53 , a third resistor  54 , a fourth resistor  55 , a fourth capacitor  56 , a fifth capacitor  57  and a voltage detector  58 . The second voltage stabilizer  51  is also a TVS, two ends of which are electrically connected to the brightness controlling module  1  and grounded, respectively. The cathode of the second Zener diode  52  is electrically connected to the voltage input terminal of the voltage detector  58 , and the anode of the second Zener diode  52  is grounded. The second resistor  53  is electrically connected at two ends thereof to the brightness controlling module  1  and to the cathode of the second Zener diode  52 , respectively. The third resistor  54  is electrically connected at two ends thereof to the cathode of the second Zener diode  52  and to the ground, respectively. The fourth resistor  55  is electrically connected at two ends thereof to the voltage input terminal of the voltage detector  58  and to the voltage output terminal of the voltage detector  58 , respectively. The fourth capacitor  56  is electrically connected at two ends thereof to the voltage input terminal of the voltage detector  58  and to the ground, respectively. The fifth capacitor  57  is electrically connected at two ends thereof to the voltage output terminal of the voltage detector  58  and to the ground, respectively. The voltage output terminal of the voltage detector  58  is electrically connected to the switching module  20 , and the ground terminal of the voltage detector  58  is grounded. In this embodiment, the voltage detector  58  is produced by ROHM Semiconductor, model no. BD4827G. 
     In addition, the switching module  20  includes a first N-MOSFET  21 , a second N-MOSFET  22 , a fifth resistor  23 , a sixth resistor  24 , a first switching unit  25 , a second switching unit  26 , a first switch  27   a , a second switch  27   b , a fourth voltage source  28  and a fifth voltage source  29 . The gate of the first N-MOSFET  21  is electrically connected to the comparing module  50 , while the drain of the first N-MOSFET  21  is electrically connected to the gate of the second N-MOSFET  22  and the first switching unit  25 . The source of the first N-MOSFET  21  is grounded. The fifth resistor  23  is electrically connected at two ends thereof to the fourth voltage source  28  and to the first switching unit  25 , respectively. The first switch  27   a  is electrically connected to the power supply controlling module  10 , the first switching unit  25  and the first color temperature light emitting module  30 . The sixth resistor  24  is electrically connected at two ends thereof to the fifth voltage source  29  and to the second switching unit  26 , respectively. The drain of the second N-MOSFET  22  is electrically connected to the second switching unit  26 , and the source of the second N-MOSFET  22  is grounded. The second switch  27   b  is electrically connected to the power supply controlling module  10 , the second switching unit  26  and the second color temperature light emitting module  40 . In this embodiment, the fourth voltage source  28  and the fifth voltage source  29  are electrically connected to each other. 
     Referring to  FIG. 3  together, a method of switchingly lighting up the first color temperature light emitting module  30  or the second color temperature light emitting module  40  of the present invention is described in more detail. Firstly, the voltage-type operating signal  2  is switched in a voltage range having a low voltage value and a high voltage value. The comparing module  50  is a window voltage detector  58 , having a first switching voltage value and a second switching voltage value between the low voltage value and the high voltage value. The first switching voltage value is lower than the second switching voltage value. In this embodiment, the voltage range is laid between 0 volts (V) and 10 volts (V), i.e., the low voltage value of 0 volts (V) and the high voltage value of 10 volts (V). Moreover, the first switching voltage value is set as 3 volts (V), while the second switching voltage value is set as 7 volts (V). 
     When the voltage-type operating signal  2  oscillates between the low voltage value and the second switching voltage value, a first switching signal of the switching signal is outputted from the comparing module  50  to the switching module  20 , and the switching module  20  is then switched for lighting up the first color temperature light emitting module  30 . Further, when the voltage-type operating signal  2  exceeds the second switching voltage value, a second switching signal of the switching signal is outputted from the comparing module  50  to the switching module  20  for switchingly lighting up the second color temperature light emitting module  40 . Afterward, when the voltage-type operating signal  2  oscillates between the high voltage value and the first switching voltage value, the second switching signal is still outputted from the comparing module  50  to the switching module  20  for lighting up the second color temperature light emitting module  40 . When the voltage-type operating signal  2  is lower than the first switching voltage value, however, the output of the comparing module  50  to the switching module  20  is then turned into the first switching signal, such that the switching module  20  is switched for lighting up the first color temperature light emitting module  30 . The purpose of this design is to prevent the problem of liability for damage due to switching between the first color temperature light emitting module  30  and the second color temperature light emitting module  40  unduly frequently because of repeated oscillation of the voltage-type operating signal  2  around the first switching voltage value or the second switching voltage value. 
     In more detail, when the first switching signal is received by the switching module  20 , the first N-MOSFET  21  is turned on, while the second N-MOSFET  22  is tuned off. Moreover, the first switching unit  25  is allowed for switching the first switch  27   a  to be shorted, and then lighting up the first color temperature light emitting module  30 . Further, when the second switching signal is received by the switching module  20 , the first N-MOSFET  21  is turned off, while the second N-MOSFET  22  is turned on. Moreover, the second switching unit  26  is allowed for switching the second switch  27   b  to be shorted, and lighting up the second color temperature light emitting module  40 . 
     In this embodiment, additionally, a sensing module  60  may be further provided. The sensing module  60  is electrically connected to the brightness controlling module  1 , and may be used for sensing the external environment. After sensing the external environment, the sensing module  60  is allowed for sending a sensing signal to the brightness controlling module  1 . The voltage-type operating signal  2  is further adjusted by the brightness controlling module  1  depending on the sensing signal, such that the modulated color temperature is capable of conforming to the current environment. Furthermore, the sensing module  60  may be the brightness, humidity, temperature and the like sensing module. 
     To sum up, the present invention is provided with features as follows: 
     1. The brightness controlling module originally provided in the street light is used for the modulation of color temperature without additional modules, so as to reduce the cost. 
     2. The problem of liability for damage due to switching between the first color temperature light emitting module and the second color temperature light emitting module unduly frequently may be prevented through providing the comparing module. 
     3. The external environment may be further sensed through providing the sensing module, such that color temperature emitted from the street light is capable of conforming to the current environment even more. 
     4. Color temperature of the street light may be changed according to the external environment through providing the first color temperature light emitting module and the second color temperature light emitting module, for the enhancement of safety of road occupant.