Patent Publication Number: US-10791604-B2

Title: Cascading LED lights with low power consumption

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a Continuation-in-Part of co-pending application Ser. No. 16/266,819, filed on Feb. 4, 2019, which claims priority to China Patent Application No. 201811625388.9, filed on Dec. 28, 2018. The entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to LED lights, and more particularly to a cascading LED lights with lower power consumption. 
     Description of Related Art 
     The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. 
     Since light-emitting diode (LED) has the advantages of high luminous efficiency, low power consumption, long life span, fast response, high reliability, etc., LEDs have been widely used in lighting fixtures or decorative lighting, such as Christmas tree lighting, lighting effects of sport shoes, etc. by connecting light bars or light strings in series, parallel, or series-parallel. 
     Take the festive light for example. Basically, a complete LED lamp includes an LED light string having a plurality of LEDs and a drive unit for driving the LEDs. The drive unit is electrically connected to the LED light string, and controls the LEDs by a point control manner or a synchronous manner by providing the required power and the control signal having light data to the LEDs, thereby implementing various lighting output effects and changes of the LED lamp. 
     With the progress of the technology, the carrier manner can be utilized for the control signal having the light data to transmit the light signal through the power line. The functions of providing power and data transmission can be achieved by the same circuit structure to simplify the layout design, reduce the volume of the circuit, and benefit the design of the control circuit. 
     However, if a plurality of LED light strings are cascaded in series, it causes the problem of failing to identify or incorrectly determining the data signal received by the next light strings due to the signal attenuation caused by the signal transmission of long distance light strings so that the next light strings fail to correctly display its lighting behavior, such as color change, light on/off manner, light on/off frequency, etc. 
     Accordingly, a quick discharge circuit can be utilized to control the light control signal to quickly reduce the voltage level of the light control signal, or the LED light string having small total parasitic capacitance easily reduces the voltage level of the light control signal quickly. However, when the light control signal quickly reduces, the light control signal easily happens that: after the light control signal is lower than the identifiable low-level voltage, the light control signal still quickly reduces so that the light control signal reaches to the reset voltage, and therefore the circuit happens unnecessary reset failure, resulting in the abnormal determination and malfunction of the LED modules. 
     SUMMARY 
     An object of the present disclosure is to provide a cascading LED lights with low power consumption to solve the above-mentioned problems. 
     In order to achieve the above-mentioned object, the cascading LED lights with low power consumption includes a master light string and at least one slave light string. The master light string includes an LED light string, an output control switch, and a controller. The LED light string has a plurality of LED modules. The output control switch is coupled to the LED light string. The controller is coupled to the output control switch, and receives a carry light signal and controls the output control switch to drive the LED modules. The at least one slave light string is cascaded to the master light string. Each slave light string includes an LED light string, an output control switch, and a signal intensifier. The LED light string has a plurality of LED modules. The output control switch is coupled to the LED light string. The signal intensifier is coupled to the output control switch, and receives the carry light signal and enhances the carry light signal, and controls the output control switch to drive the LED modules. When a voltage of the carry light signal is less than a low-level voltage, each of the LED modules enters a low-power-consumption mode. 
     In one embodiment, the master light string further includes an output connector. The output connector has a positive voltage terminal, a negative voltage terminal, and a data terminal. The slave light string further includes an input connector. The input connected has two power pins and a data pin. The two power pins are respectively coupled to the positive voltage terminal and the negative voltage terminal, and the data pin is coupled to the data terminal. 
     In one embodiment, the slave light string further includes an output connector. The output connected is coupled to the input connector of another slave light string. 
     In one embodiment, the signal intensifier includes a control switch and a signal converter and shaper. The signal converter and shaper is coupled to the control switch. When the control switch is turned on, the signal converter and shaper receives the carry light signal and enhances the carry light signal. 
     In one embodiment, the data terminal is coupled between the last LED module and the second last LED module. 
     In one embodiment, each LED module includes a voltage comparison unit. When the voltage of the carry light signal is less than the low-level voltage, the voltage comparison unit outputs a control signal to control each LED module entering a sleep state of the low-power-consumption mode. 
     In one embodiment, each LED module includes a current detection unit. When the voltage of the carry light signal is less than the low-level voltage, the current detection unit outputs a control signal to control each LED module entering an eco state of the low-power-consumption mode. 
     In one embodiment, within a time interval after entering the eco state of the low-power-consumption mode, each LED module is configured to perform the signal detection and the signal recognition; after the time interval, the control signal controls each LED module entering a sleep state of the low-power-consumption mode. 
     In one embodiment, each LED module further includes an oscillator. In the eco state of the low-power-consumption mode, the oscillator receives the control signal, and the oscillator is controlled by the control signal to be in an oscillation operation at low power. 
     In one embodiment, each LED module further includes a latch unit and an oscillator. In the eco state of the low-power-consumption mode, the latch unit and the oscillator receive the control signal, and the oscillator is controlled by the control signal to be disabled and the latch unit is controlled by the control signal to be in a timing operation. 
     In one embodiment, the latch unit is a charging and discharging circuit with a resistor and a capacitor. 
     In one embodiment, the latch unit is a timing circuit. 
     Accordingly, the cascading LED lights with low power consumption solve the problem of failing to identify or incorrectly determining the data signal received by the next light strings due to the signal attenuation caused by the signal transmission of long distance light strings, and by shortening the wiring distance between the data terminal and the LED light string, the control switch be driven by a sufficiently large control voltage regardless of the voltage decay affected due to the wire length so that the control switch can be normally turned on and turned off to ensure that the signal intensifier can normally operate. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the present disclosure as claimed. Other advantages and features of the present disclosure will be apparent from the following description, drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
       The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1  is a circuit block diagram of a master light string of a cascading LED lights with low power consumption according to the present disclosure. 
         FIG. 2  is a detailed circuit diagram of the master light string of the cascading LED lights with low power consumption according to the present disclosure. 
         FIG. 3  is a detailed circuit diagram of a slave light string of the cascading LED lights with low power consumption according to the present disclosure. 
         FIG. 4  is a schematic view of cascading the master light string and the slave light string according to the present disclosure. 
         FIG. 5  is a circuit block diagram of an LED module according to a first embodiment of the present disclosure. 
         FIG. 6  is a circuit block diagram of the LED module according to a second embodiment of the present disclosure. 
         FIG. 7  is a circuit diagram of a voltage comparison unit according to the present disclosure. 
         FIG. 8  is a schematic waveform of a light drive signal according to the present disclosure. 
         FIG. 9  is a circuit block diagram of the LED module according to a third embodiment of the present disclosure. 
         FIG. 10  is a circuit block diagram of the LED module according to a fourth embodiment of the present disclosure. 
         FIG. 11  is a schematic waveform of a light drive signal according to the present disclosure. 
         FIG. 12  is a schematic circuit diagram of an oscillator according to the present disclosure. 
         FIG. 13  is a schematic waveform of operating a latch unit according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the drawing figures to describe the present disclosure in detail. It will be understood that the drawing figures and exemplified embodiments of present disclosure are not limited to the details thereof. 
     Please refer to  FIG. 1 , which shows a circuit block diagram of a master light string of a cascading LED lights with low power consumption according to the present disclosure. The master light string  90  of the cascading LED lights (hereinafter referred to as “master light string  90 ”) mainly includes a controller  100 , an output control switch Qsw, an LED (light-emitting diode) light string  30 , and an output connector  70 . 
     The controller  100  is coupled to an AC power Vac and the output control switch Qsw, and converts the AC power Vac to provide enough power for driving the LED light string  30  and turning on or turning off the output control switch Qsw. 
     The output connector  70  has a positive voltage terminal V+, a negative voltage terminal V−, and a data terminal Do. The positive voltage terminal V+ and the negative voltage terminal V− are coupled to a positive voltage and a negative voltage of a DC power converted by the controller  100 , respectively. The data terminal Do receives the carry light signal (having light data and address data) for controlling light effects and changes outputted from each of a plurality of LED modules  31 ,  32 , . . . ,  3   n . The functions of providing power and data transmission can be achieved by the same circuit structure to simplify the layout design, reduce the volume of the circuit, and benefit the design of the control circuit. 
     Please refer to  FIG. 2 , which shows a detailed circuit diagram of the master light string of the cascading LED lights with low power consumption according to the present disclosure. Specifically,  FIG. 2  shows a detailed circuit diagram of the controller  100 . The power conversion circuit  10  and the control circuit  20  may be integrated into a controller  100 . Specifically, the controller  100  may be implemented by a physical circuit control box including the power conversion circuit  10  and the control circuit  20 . The power conversion circuit  10  receives an AC power Vac and converts the AC power Vac into a DC power Vdc. The DC power Vdc is across an output capacitor (not labeled) connected at output terminals of the power conversion circuit  10 . 
     The control circuit  20  receives the DC power Vdc to supply the required DC power for the control circuit  20  and the LED light string  30 . The controller  100  is coupled to the AC power Vac and the LED light string  30  through a power line. In one embodiment, the LED light string  30  includes a plurality of LED modules  31 ,  32 , . . . ,  3   n  (also refer to the LED light). The LED modules  31 ,  32 , . . . ,  3   n  are connected in series and electrically coupled to the output control switch Qsw. In one embodiment, the LED light string  30  is a light string having data burning function, and therefore each of the LED modules  31 ,  32 , . . . ,  3   n  has own digital and analog circuits for burning light data and address data. 
     Please refer to  FIG. 3 , which shows a detailed circuit diagram of a slave light string of the cascading LED lights with low power consumption according to the present disclosure. The slave light string of the cascading LED lights (hereinafter referred to as “slave light string  91 ”) mainly includes an input connector  71 , a signal intensifier  80 , an output control switch Qsw, an LED light string  30 , and an output connector  70 . In particular, the operations of the output control switch Qsw, the LED light string  30 , and the output connector  70  of the slave light string  91  is same as those of the master light string  90 , and the detail description is omitted here for conciseness. The input connector  71  has three pins correspondingly to the positive voltage terminal V+, the negative voltage terminal V−, and the data terminal Do of the of the output connector  70  of the master light string  90  or the previous slave light string  91 . Therefore, the three pins are correspondingly connected to the positive voltage terminal V+, the negative voltage terminal V−, and the data terminal Do when the slave light string  91  is plugged into the master light string  90  (or the previous slave light string  91 ), and therefore the power and the data can be transmitted to the next slave light string  91 . 
     The signal intensifier  80  includes two voltage-divided resistor networks, a control switch Qc, and a signal converter and shaper  81 . One voltage-divided resistor network is composed of resistors R 31 , R 32 , and the other voltage-divided resistor network is composed of resistors R 33 , R 34 . The resistors R 31 , R 32  are coupled to a control end (for example a gate) of the control switch Qc, and the resistors R 33 , R 34  are coupled to a power end (for example a drain) of the control switch Qc for operations of voltage division. Further, by turning on the control switch Qc, the signal converter and shaper  81  can convert and enhance the data signal transmitted from the previous light string to sufficiently drive the output control switch Qsw, thereby solving the problem of failing to identify or incorrectly determining the data signal received by the next light strings due to the signal attenuation caused by the signal transmission of long distance light strings. Specifically, if a voltage divided by the resistors R 31 , R 32  is not sufficient to turn on the control switch Qc, i.e., the control switch Qc is turned off, the signal converter and shaper  81  does not receive a voltage divided by the resistors R 33 , R 34 . On the contrary, if the voltage divided by the resistors R 31 , R 32  is sufficient to turn on the control switch Qc, the signal converter and shaper  81  receives the voltage divided by the resistors R 33 , R 34 . Therefore, the signal converter and shaper  81  can duplicate the signal waveform of the data signal transmitted from the previous light string to provide sufficient signal strength to drive turning on the output control switch Qsw. 
     Please refer to  FIG. 4 , which shows a schematic view of cascading the master light string and the slave light string according to the present disclosure.  FIG. 4  shows one master light string  90  is cascaded to a plurality of slave light strings  91 . That is, the input connector  71  of the first slave light string  91  is plugged into the output connector  70  of the master light string  90 , and the input connector  71  of the second slave light string  91  is plugged into the output connector  70  of the first slave light string  91 , and so on, thereby forming the cascading LED lights. Moreover, the signal intensifier  80  of each slave light string  91  can enhance the data signal transmitted from the previous light string so that the data signal received by the next slave light string  91  can be correctly identified. In particular, as shown in  FIG. 1  (master light string  90 ) or  FIG. 3  (slave light string  91 ) and take the cascaded master light string  90  and slave light string  91  for example. In order to make the control switch Qc of the signal intensifier  80  of the slave light string  91  be driven by a sufficiently large control voltage, the resistances of the resistors R 31 , R 32  can be specially designed as well as a wiring distance between the data terminal Do and the LED light string  30  can be shortened. For example, the data terminal Do may be coupled to a contact P 1  between the last LED module  3   n  and the second last LED module  3   n - 1 , or the data terminal Do may be coupled to a contact P 2  between the second last LED module  3   n - 1  and the third last LED module  3   n - 2 . Accordingly, the control switch Qc can be driven by a sufficiently large control voltage regardless of the voltage decay affected due to the wire length so that the control switch Qc can be normally turned on and turned off to ensure that the signal intensifier  80  can normally operate. 
     Please refer to  FIG. 5 , which shows a circuit block diagram of an LED module according to a first embodiment of the present disclosure. As mentioned above, the LED light string  30  is a light string having data burning function, and therefore each of the LED modules  31 ,  32 , . . . ,  3   n  has own digital and analog circuits for burning light data and address data. For example, a light control unit  311  is responsible for controlling illumination, an address signal process unit  312  is responsible for processing address signal, and an addressing burn unit  313  is responsible for burning address. Take the LED module  31  shown in  FIG. 5  for example, and the remaining LED modules  32 , . . . ,  3   n  have the same circuit topologies and will not be described again. The LED module  31 , i.e., the LED light includes a voltage stabilizer  41 , an oscillator  42 , an address and data identifier  43 , a logic controller  44 , a shift register  45 , an output buffer register  46 , a drive circuit  47 , an address register  48 , an address comparator  49 , an address memory  50 , an address burn controller  51 , a burn signal detector  52 , a signal filter  53 , a discharge unit  54 , a current detector  55 , and a voltage comparison unit  56 . 
     Since the LED module  31  shown in  FIG. 5  is applied to the in-series connection, the voltage stabilizer  41  is necessary for voltage regulation and voltage stabilization. Since the LED module  31  shown in  FIG. 5  operates by a point control manner, the LED module  31  includes the address signal process unit  312  and the addressing burn unit  313  for processing (including determining, memorizing, burning, etc.,) address data. That is, the address register  48 , the address comparator  49 , the address memory  50 , the address burn controller  51 , the burn signal detector  52  are involved. In other words, if the LED module  31  operates by a synchronous control, the address signal process unit  312  and the addressing burn unit  313  can be omitted, that is, only the light control unit  311  with processing light data is necessary. 
     In the above circuit, the difference in signal characteristics can be divided into analog circuits and digital circuits. The voltage stabilizer  41 , the oscillator  42 , the address burn controller  51 , the burn signal detector  52 , and the discharge unit  54  belong to the analog circuits, and others belong to the digital circuits. In different embodiments, however, the address burn controller  51  and the burn signal detector  52  may be implemented by both the analog circuit and the digital circuit. In comparison with the low power consumption of the digital circuits, the analog circuits, including the voltage stabilizer  41 , the oscillator  42 , the light control unit  311 , the address signal process unit  312 , the addressing burn unit  313 , and the discharge unit  54  are the circuit components with relatively high power consumption of the LED module  31 . 
     Please refer to  FIG. 6 , which shows a circuit block diagram of the LED module according to a second embodiment of the present disclosure. As mentioned above, since the LED module shown in  FIG. 6  is applied to the in-parallel connection, the voltage stabilizer  41  is unnecessary for voltage regulation and voltage stabilization. The operations of the remaining circuits are the same in  FIG. 5 , and the detail description is omitted here for conciseness. 
     In order to effectively reduce the power consumption of the analog circuits and normally operate the LED module  31 , the LED module further includes a voltage comparison unit  56  for voltage comparison. Take a voltage signal as the light drive signal for example, the voltage comparison unit  56  receives the light drive signal Vd and a predetermined reference voltage value Vth. Please refer to  FIG. 7 , in this embodiment, the voltage comparison unit  56  is implemented by an operational amplifier. A non-inverting input end of the voltage comparison unit  56  receives the light drive signal Vd and an inverting input end of the voltage comparison unit  56  receives the reference voltage value Vth, and the voltage comparison unit  56  compares the light drive signal Vd with the reference voltage value Vth. If the light drive signal Vd is greater than the reference voltage value Vth, the voltage comparison unit  56  outputs a high-level control signal Sc. On the contrary, if the light drive signal Vd is less than the reference voltage value Vth, the voltage comparison unit  56  outputs a low-level control signal Sc. However, this is not a limitation to this present disclosure. The inverting input end may receive the light drive signal Vd and the non-inverting input end may receive the reference voltage value Vth, and the control signal Sc with the opposite level can be acquired after the voltage comparison unit  56  compares the light drive signal Vd with the reference voltage value Vth. Similarly, the determination of the light drive signal Vd can be achieved. Further, the determination of the light drive signal Vd can be implemented without limitation using an operational amplifier circuit, and any circuit usable for voltage comparison should be included in the scope of the present invention. 
     Please refer to  FIG. 8 , which shows a schematic waveform of a light drive signal according to the present disclosure. As mentioned above, when the control unit CONR turns off the output control switch Qsw, the voltage outputted from the LED light string  30  is reduced by the discharging manner so as to provide a low-level voltage of a light drive signal Vd for each of the LED modules  31 ,  32 , . . . ,  3   n  of the LED light string  30 . Alternatively, the quick discharging circuit (not shown) inside each of the LED modules  31 ,  32 , . . . ,  3   n  is controlled to quickly reduce the voltage generated from a light signal voltage generation circuit to provide the low-level voltage of the light drive signal Vd for each of the LED modules  31 ,  32 , . . . ,  3   n  of the LED light string  30 . Moreover, by comparing the light drive signal Vd with the reference voltage value Vth by the voltage comparison unit  56 , it is to avoid unnecessary reset failure of the circuits to cause determination abnormality and malfunction of the LED module  31  since the light drive signal Vd quickly reduces to reach to the reset voltage Vreset during the quick discharging operation. 
     Specifically, as shown in a second waveform Cv 2 . At a time point t 1 , the output control switch Qsw is controlled to be turned off by the control unit CONR. At this condition, the light drive signal Vd quickly reduces. At the time point t 12 , when the light drive signal Vd reaches to the reference voltage value Vth, the voltage comparison unit  56  shown in  FIG. 7  compares two voltages and outputs the control signal Sc with the low level since the light drive signal Vd is less than (or less than or equal to) the reference voltage value Vth, thereby avoiding the light drive signal Vd further quickly reducing. The control signal Sc produced from the voltage comparison unit  56  is to control, for example but not limited to, the analog circuits with higher power consumption in the LED module  31 . As shown in  FIG. 5 , when the voltage stabilizer  41 , the oscillator  42 , the light control unit  311 , the address signal process unit  312 , the addressing burn unit  313 , and the discharge unit  54  enter a sleep mode or an eco mode, thereby significantly reducing the power consumption of the LED module  31  to slow the reduction speed of the light drive signal Vd. Incidentally, in order to simplify the  FIG. 5  and  FIG. 6 , the control signal Sc inputting to the voltage stabilizer  41 , the oscillator  42 , the address burn controller  51 , the burn signal detector  52 , and the discharge unit  54  is actually from the voltage comparison unit  56  coupled to the voltage stabilizer  41 , the oscillator  42 , the address burn controller  51 , the burn signal detector  52 , and the discharge unit  54  respectively, and the voltage comparison unit  56  provides the control signal Sc to the circuit units. 
     After the time point t 2  shown in  FIG. 8 , when the light drive signal Vd is less than the reference voltage value Vth, since the above-mentioned analog circuits enter the sleep mode, the reduction speed of the light drive signal Vd slows down to avoid reaching to the reset voltage Vreset. Incidentally, quick discharge detection, effectively reducing power consumption, and correctly determining (identifying) the low level voltage of the light drive signal Vd can be achieved by designing that the low level voltage for identifying the light drive signal Vd is the reference voltage value Vth, or is slightly less than the reference voltage value Vth but is greater than the voltage value of the reset voltage Vreset, and therefore the LED module  31  can be normally driven and can normally operate. For example, the reset voltage Vreset may be designed as 0.7 volts, the reference voltage value Vth may be designed as 1.1 volts, and the low-level voltage of the light drive signal Vd may be designed as 1.1 volts (or smaller 0.8 to 1.0 volt). Cooperating with the requirement of the response or the action of the whole circuit, the present disclosure can properly design and adjust the reset voltage Vreset, the reference voltage value Vth, and the low-level voltage of the light drive signal Vd. 
     Until a time point t 3 , the control unit CONR turns on the output control switch Qsw to restore (increase) the output voltage outputted to the LED light string  30 , and produces the light drive signal Vd according to the light control data Sec received by the control unit CONR so that the LED light string  30  proceeds the operation of the light mode according to the light drive signal Vd. Therefore, since the light drive signal Vd is greater than the reference voltage value Vth, the control signal Sc produced by the voltage comparison unit  56  is transited from the low level to the high level so that the control signal Sc controls the voltage stabilizer  41 , the oscillator  42 , the light control unit  311 , the address signal process unit  312 , the address burn unit  313  and the discharge unit  54  to leave the sleep mode and to restore the normal operations of the circuit units. Similarly, the remaining LED modules  32 , . . . ,  3   n  are controlled by the subsequent cycles of the light drive signal Vd, and the detail description is omitted here for conciseness. Therefore, the operations of driving and controlling all the LED modules  31 ,  32 , . . . ,  3   n  of the LED light string  30  are accomplished. 
     Please refer to  FIG. 9 , which shows a circuit block diagram of the LED module according to a third embodiment of the present disclosure. In comparison with  FIG. 5 , since the control signal Sc is produced by the current detector  55  instead of the voltage comparison unit  56 , the absence of the voltage comparison unit  56  is illustrated in the third embodiment. Please refer to  FIG. 11 , when the control unit CONR turns off the output control switch Qsw, the voltage outputted from the LED light string  30  is reduced by the discharging manner so as to provide a low-level voltage of a light drive signal Vd for each of the LED modules  31 ,  32 , . . . ,  3   n  of the LED light string  30 . Alternatively, the quick discharging circuit (not shown) inside each of the LED modules  31 ,  32 , . . . ,  3   n  is controlled to quickly reduce the voltage generated from a light signal voltage generation circuit to provide the low-level voltage of the light drive signal Vd for each of the LED modules  31 ,  32 , . . . ,  3   n  of the LED light string  30 . In particular, three modes are provided to control the LED modules  31 ,  32 , . . . ,  3   n  in the present disclosure. The first mode is a work mode, the second mode is an eco mode, and the third mode is a sleep mode. Therefore, the LED modules  31 ,  32 , . . . ,  3   n  can normally operate and meet the requirement of low power consumption. 
     The work mode means that internal circuits, including analog circuits and digital circuits in each of the LED modules  31 ,  32 , . . . ,  3   n  can normally operate. In order to achieve the purpose of low power consumption, the eco mode first operates, and then the sleep mode operates. The purpose of the eco mode is to first turn off (disable) the analog circuits with higher power consumption. The cooperation consideration between the oscillator and the digital circuits is necessary, however, the analog circuits except the oscillator or the analog circuits involving the oscillator are first turned off (disabled) in the eco mode to significantly reduce more power consumption and maintain the normal operation of the digital circuits, and therefore signal detection and signal recognition can normally work. In the eco mode, the oscillator is controlled to be in an oscillation operation at low power without turning off. After the signal detection and signal recognition is completed, the oscillator is turned off to enter the sleep mode. Accordingly, it is to avoid unnecessary reset failure of the circuits to cause determination abnormality and malfunction of the LED module  31  since the light drive signal Vd quickly reduces to reach to the reset voltage Vreset during the quick discharging operation. 
     Specifically, as shown in  FIG. 11 . Before the time point t 11 , the output control switch Qsw is controlled to be turned on by the control unit CONR, and therefore each of the LED modules  31 ,  32 , . . . ,  3   n  is in the work mode. At the time point t 11 , the output control switch Qsw is controlled to be turned off by the control unit CONR. At this condition, the light drive signal Vd quickly reduces. At the time point t 12 , the light drive signal Vd reaches to the low-level voltage Vlow so as to identify that the light drive signal Vd is a proper drive signal for driving the LED modules  31 ,  32 , . . . ,  3   n  (the following description is based on the LED module  31 ). However, in order to avoid unnecessary reset failure of the circuits to cause determination abnormality and malfunction of the LED module  31  since the light drive signal Vd gradually reduces to reach to the reset voltage Vreset, it is to enter the eco mode at the time point t 12 . The analog circuits except the oscillator or the analog circuits involving the oscillator are first turned off (disabled) to significantly reduce more power consumption. Moreover, in order to maintain the normal operation of the digital circuits and the oscillator, the signal detection and signal recognition must be completed within a time interval T, and then it is to enter the sleep mode at the time point t 13 , thereby significantly reducing power consumption of the LED module  31 . The time interval T means a time interval between the time point t 12  and the time point t 13 , for example but not limited to, a time length of several (3 or 4) clock cycles. Therefore, after the time point t 13 , the oscillator is completely turned off so that the power consumption of the LED module  31  is minimized. Accordingly, it is not only to optimize the low power consumption but also to avoid causing abnormal conditions since the light drive signal Vd reduces to reach to the reset voltage Vreset. At the time point t 14 , the output control switch Qsw is controlled to be turned on by the control unit CONR, and therefore the voltage level of the light drive signal Vd is restored. At this condition, since the voltage level of the light drive signal Vd is greater than the low-level voltage Vlow, it is to leave the sleep mode and enter the work mode again in the next cycle. 
       FIG. 11  further shows the light drive signal Vd with a narrow-width cycle, for example but not limited to 1 microsecond. In comparison with the narrow-width cycle, a wide-width cycle between the time point t 11  and the time point t 14  is about 3 microseconds. The difference between the narrow-width cycle and the wide-width cycle is that the voltage level of the light drive signal Vd is restored before the time interval T has ended (i.e., before entering the sleep mode) in the former. At this condition, since the output control switch Qsw is controlled to be turned on by the control unit CONR, the voltage level of the light drive signal Vd is restored to enter the work mode again, thereby avoiding causing abnormal conditions since the light drive signal Vd reduces to reach to the reset voltage Vreset. 
     Therefore, the features of the present disclosure focus on both effectively reducing the power consumption of the analog circuits in the eco mode and the sleep mode and normally operating the LED module  31 , and the detail description can be referred to  FIG. 5  and is omitted here for conciseness. 
     Please refer to  FIG. 10 , which shows a circuit block diagram of the LED module according to a fourth embodiment of the present disclosure. In comparison with the third embodiment shown in  FIG. 9 , the LED module  31  further includes a latch unit  57 , the remaining circuits are the same in  FIG. 9 . The latch unit  57  is coupled between an input side and an output side inside the LED module  31 . The latch unit  57  is used to replace the oscillator  42  in the sleep mode so that the LED module  31  can continuously perform the signal detection and signal recognition. In one embodiment, the latch unit  57  may be an analog charging and discharging circuit composed of a resistor and a capacitor. 
     Hereinafter, a description will be given of how the present disclosure achieves reducing power consumption and saving energy. Please refer to  FIG. 11 , when the light drive signal Vd reaches to the low-level voltage Vlow (at the time point t 12  or time point t 22  shown in  FIG. 11 ), the current detector  55  produces the control signal Sc. At this condition, the analog circuit with relatively high power consumption of the LED module  31  such as the voltage stabilizer  41 , the oscillator  42 , the address burn controller  51 , the burn signal detector  52 , and the discharge unit  54  are controlled by the control signal Sc to enter the eco mode, thereby reducing the main source of power consumption. The eco mode can be regarded as a first stage control mode to reduce power consumption. However, since the operation of the digital circuits is closely related to the oscillator  42  and in order to ensure that the digital circuit can perform its necessary operation, the oscillator  42  is then controlled to enter to the sleep, which can be regarded as a second stage control mode to reduce power consumption. Specifically, two embodiments are proposed to reduce the power consumption of the oscillator  42  in the eco mode. The first one is that the oscillator  42  is controlled to be in an oscillation operation at low power without turning off, and the second one is that the oscillator  42  is replaced by the charging and discharging circuit. 
     Please refer to  FIG. 12 , which shows a schematic circuit diagram of an oscillator according to the present disclosure, and also refer to  FIG. 9 . In terms of control accuracy, the best manner is to use the oscillator  42  to produce the periodic clock signal as the time reference. However, in order to have requirements of accurate control and low-power consumption, the specific design of the oscillator  42  is provided to implement the low-power oscillation in a first embodiment. The oscillator  42  shown in  FIG. 12  includes a plurality of inverters In 11 -In 22 , a resistor Ro, and a capacitor Co. However, the connection thereof is for illustrative purposes only, and is not intended to limit the present disclosure. The inverters In 11 -In 22  are CMOS transistor circuit inverters. The design of different transistor sizes and the control of enabling and disabling are implemented to achieve the accurate control and low power consumption. For example, but not limited to that the size of the inverter In 12  and the size of the inverter In 22  are smaller than that of the inverter In 11  and that of the inverter In 21 , respectively. Further, the inverter In 11  and the inverter In 21  are controlled by the control signal Sc. 
     When the oscillator  42  normally operates, i.e., the LED module  31  is in the work mode (before the time point t 12  shown in  FIG. 11 ), the inverters In 11 -In 22  are enabled. At this condition, the oscillator  42  operates at a full-power condition to provide a clock signal. When the light drive signal Vd reaches to the low-level voltage Vlow (at the time point t 12  shown in  FIG. 11 ), the control signal Sc produced from the current detector  55  controls the inverter In 11  and the inverter In 21  to be disabled, at this condition, the inverter In 12  and the inverter In 22  are still enabled. Alternatively, the inverter In 12  and inverter In 22  may be controlled by the control signal Sc to be disabled, but the inverter In 11  and the inverter In 21  are still enabled. Accordingly, the oscillator  42  can be controlled by the control signal Sc to be in an oscillation operation at low power, thereby ensuring that the digital circuit can perform its necessary operation and implementing the lower power consumption of the oscillator  42 . Until the LED module  31  completes the signal detection and signal recognition within the time interval T between the time point t 12  and the time point t 13  shown in  FIG. 11 , the oscillator  42  is turned off to enter to the sleep mode after the time point t 13 . However, the connection relationship, the number, the size, and the signal control manner of the inverters In 11 -In 22  are for illustrative purposes only and are not intended to limit the present disclosure. 
     Please refer to  FIG. 13 , which shows a schematic waveform of operating a latch unit according to the present disclosure, and also refer to  FIG. 10 . In order to respond the light drive signal Vd with wider width (for example but not limited to 6 to 8 microsecond) as a latch signal for ending the signal recognition, a latch unit  57  is provided as shown in  FIG. 10 . The latch unit  57  is used to make end the signal recognition being correct to avoid too early turning off the oscillator  42  to cause the digital circuits to be out of order and malfunction. Moreover, in order to early turn off the oscillator  42  with relatively high power consumption to achieve low power consumption, the latch unit  57  having charging and discharging functions is proposed by a resistor-capacitor charging and discharging circuit, thereby replacing the timing function of the oscillator  42 . As mentioned above, for the light drive signal Vd with 3-microsecond or 1-microsecodn cycle width (as shown in the first two cycle signals in  FIG. 13 ). Since the first two cycle signals are not latching signals, a discharge voltage Vdis is greater than a predetermined latch voltage Vlatch, wherein the discharge voltage Vdis is provided by discharging operation through a capacitor of the latch unit  57 . Alternatively, a charging operation of the capacitor of the latch unit  57  may be provided to achieve the similar determination. At this condition, a latch determine signal Slatch is low level, and the oscillator  42  can operate at low power in the eco mode and be turned off in the sleep mode, thereby implementing lower power consumption. 
     When the light drive signal Vd is the latching signal with 6-microsecond to 8-microsecond cycle width (as shown in the third cycle signal in  FIG. 13 ), the discharge voltage Vdis is equal to or less than the latch voltage Vlatch at the time point t 1  since the discharging time of the capacitor of the latch unit  57  is longer. At this condition, that latch determine signal Slatch is transited from the low level to the high level. Moreover, by continuously discharging the capacitor of the latch unit  57 , it is to ensure that the light drive signal Vd as the latching signal to be normally detected and controlled after the oscillator  42  is turned off. Until the time point t 2 , since the output control switch Qsw is controlled to be turned on by the control unit CONR, the voltage level of the light drive signal Vd is restored. At this condition, since the voltage level of the light drive signal Vd is greater than the low-level voltage Vlow, the latch determine signal Slatch is transited from the high level to the low level, and therefore it is to leave the sleep mode and enter the work mode again in the next cycle. 
     However, the detection and control of the latching signal are not limited by comparing the discharge voltage Vdis with the latch voltage Vlatch. Alternatively, a predetermined time length is set for latching operation of the latch unit  57 . For example, the latch unit  57  may be implemented by a timing circuit. Therefore, when the predetermined time length reaches or exceeds, the latching operation of the latch unit  57  is activated to meet the requirement of low power consumption. 
     In conclusion, the present disclosure has following features and advantages: 
     1. The data signal transmitted from the previous light string is enhanced (increased) by the signal converter and shaper to solve the problem of failing to identify or incorrectly determining the data signal received by the next light strings due to the signal attenuation caused by the signal transmission of long distance light strings. 
     2. By shortening the wiring distance between the data terminal and the LED light string, the control switch be driven by a sufficiently large control voltage regardless of the voltage decay affected due to the wire length so that the control switch can be normally turned on and turned off to ensure that the signal intensifier can normally operate. 
     3. In the same architecture, the light drive signal and the power supplying source are both transmitted to the LED light string. 
     4. The quick discharging circuit inside each of the LED modules is provided to quickly reduce the voltage level of the light drive signal to ensure that all in-series LEDs are completely controlled. 
     5. The simple application circuits are provided to solve determination abnormality and malfunction of the LED module since the light drive signal reduces to reach to the reset voltage. 
     6. It is to effectively reduce power consumption of the analogy circuits with relatively high power consumption and to make the LED module normally operate. 
     7. The LED module operates by the point control or by the synchronous control, and therefore to increase flexibility and convenience of designing the control circuit and implement diverse lighting effects and changes of the LED lamp. 
     8. The specific design of the oscillator is provided to implement the low-power oscillation, provide the clock signal, and ensure that the digital circuit can perform its necessary operation before the oscillator enters the sleep mode, thereby achieving the lower power consumption of the oscillator. 
     9. The charging and discharging time design and the predetermined time design of the latch unit ensure that the light drive signal as the latching signal to be normally detected and controlled, thereby achieving the lower power consumption of the oscillator. 
     Although the present disclosure has been described with reference to the preferred embodiment thereof, it will be understood that the present disclosure is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the present disclosure as defined in the appended claims.