Abstract:
An angle adjustment mechanism for LED bar lighting includes a lamp body, two end covers arranged two ends of the lamp body along an axial direction thereof, two lamp frames respectively mounted on the two threading pipes, two wheel gears respectively fixed on the two lamp frames, two outer end caps fixed and covered on the two end covers, respectively, and at least two stopping plates respectively received in the two lamp frames. Each of the two end covers includes a threading pipe extending along the axial direction of the lamp body. Each of the two wheel gears includes a plurality of gear teeth taken along a radial direction thereof and rotating around the threading pipe. Each of the stopping plates provides at least one stopping tooth which is coupling to the gear teeth.

Description:
RELATED APPLICATION 
       [0001]    This present application claims benefit of the Chinese Application, CN201610454742.0, filed on Jun. 22, 2016. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present application relates to a lighting power supply device, and more particularly to a power supply circuit for LED lighting. 
         [0004]    2. Description of the Related Art 
         [0005]    Light emitting diode (LED) is growing in popularity due to decreasing costs and long life compared to incandescent lighting and fluorescent lighting. Recently, a number of LED lighting apparatuses have been designed to replace the halogen apparatus, as well as other traditional incandescent or fluorescence lighting apparatuses. In some places such as exhibition halls, jewelry stores, museums, supermarkets, and some home lighting, such as large villas, will use a lot of strip LED lamps. Moreover, in addition to lighting equipments, such as general traffic lights, billboards, motor-lights, etc., also use light-emitting diodes as light source. As described above, for the light-emitting diodes as a light source, the advantage is power saving, and the greater brightness. Therefore, the use has been gradually common. 
         [0006]    As well known, power supply, which affects the life of LED lamps, as one of the most important factors, is also the object of concern. General LED power supply has output short protection circuit. The output short protection circuit may means that the power supply outputs very low system input power or low frequency power when the short circuit occurs. And after the withdrawal of the short circuit, the power supply can automatically return to normal work. However, with the increase of energy-saving awareness and light distribution requirements, a current-sensitive components, such as MOS tube, may be electrically connected in series between the power outputs and the LED lamp load. Therefore, when the LED light load is in short circuit, the output circuit must output a large impact current, and the impact current in the moment will reach tens to hundreds of amps. The impact current is often far more than the ultimate tolerance of the current-sensitive components. As a result, these current-sensitive components will be breakdown and the power supply fails. 
         [0007]    Therefore, it is necessary to provide a power supply circuit for LED lighting having short circuit protection which makes it possible to prevent the power supply from failing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout two views. 
           [0009]      FIG. 1  is a block diagram of a power supply circuit for LED lighting according to an embodiment. 
           [0010]      FIG. 2  is a circuit diagram of the power supply circuit for LED lighting of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The present application is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. It should be noted that references to “an” or “one” embodiment in this application are not necessarily to the same embodiment, and such references mean at least one. 
         [0012]    Referring to  FIG. 1  to  FIG. 2 , a power supply circuit  100  for LED lighting is shown. The power supply circuit  100  for LED lighting includes an LED power prime circuit  10 , a load  20  electrically connected to the output ends of the LED power prime circuit  10 , a short circuit protection switch module  30  electrically connected between the LED power prime circuit  10  and the load  20 , a circuit detecting module  40 , and a controlling switch module  50  configured for controlling the short circuit protection switch module  30  to be turn on or turn off according to a detecting signal from the circuit detecting module  40 . It may be understood that the power supply circuit for LED lighting further includes other function modules, such as cooling module, discharge control module, or the like, which is well known by these persons skilled in the art and not described in detail. 
         [0013]    The LED power prime circuit  10  is an ordinary power supply circuit which is configured for transforming the mains to a current suitable for using in the load  20 , such as frequency, amplitude, size, or the like. The output voltage of the LED power prime circuit  10  should be a rated voltage of the load  20  of subsequent stage, and the load  20  may be LED lamps, and the normal voltage thereof may be 30V or 24V. As for the specific circuit configuration within the LED power prime circuit  10 , it is not the focus of the present invention and not described in detail. 
         [0014]    The load  20  may be one or plurality of LED lightings, which may be electrically connected in parallel or in series and will not be described here. The load  20  is electrically connected to the output ends of the LED power prime circuit  10  and is powered thereby. In general use, since the load  20  is constituted of a number of LED chips, such as LED bar lights, LED strips, COB LED chips, which includes a number of LED chips, it is difficult to ensure that each of the LED chips have same life, or one or more of the LED chips is not damaged in use. Once one or more of the LED chips are damaged, which will cause a short circuit. Therefore, in order to protect other LED chips, and the LED power supply, the general LED power supply are set up short circuit protection to achieve this goal. 
         [0015]    The short circuit protection switch module  30  is electrically connected between the load  20  and the LED power prime circuit  10 , and configured for turning off the LED power prime circuit  10  in time when the load  20  is short-circuited. That is to say, the LED power supply circuit  10  is turned off and stops supplying power to the load  20  so as to avoid damaging the load  20  or damaging the LED power supply circuit  10  due to an excessive output current. Thus, the short circuit protection switch module  30  includes a load switch  301  for turning off the power input. Referring to  FIG. 2 , the short circuit protection switch module  30  includes two resisters R 1 , R 2  in series, and an N-channel MOS Q 7  electrically connected in parallel to the resister R 2 . The resisters R 1 , R 2  are configured for providing a suitable turn-on voltage for the MOS Q 7  by a partial voltage as characteristics of MOS tube as the conduction voltage of the MOS tube cannot be too high and it will burn. The N-channel MOS Q 7  is the load switch  301  described above. Of course, it may be understood that the P-channel MOS tube, or other switchers can be used in the short circuit protection switch module  30  by changing the circuit design. A gate of the N-channel MOS Q 7  is electrically connected to the controlling switch module  50  and the resisters R 1 , R 2 , and a source thereof is grounded, and a drain thereof is electrically connected to an input of the load  20 . Another input terminal of the load  20  is electrically connected to the output terminal of the LED power prime circuit  10 . It is of course understood that when the power supply circuit  100  for LED lighting has a color-temperature adjustment signal or a dimming signal, these signal may be a PWM signal, the color-temperature adjustment signal or the dimming signal as well known is also connected to the gate of the N-channel MOS Q 7  so as to achieve the purpose of adjusting the output by controlling the time ration of the ON/OFF of the N-channel MOS Q 7 . 
         [0016]    The circuit detecting module  40  is used to detect whether or not the load  20  has a short circuit condition. When the load  20  has no the short circuit condition, the circuit detecting module  40  outputs a controlling signal for controlling the control switch module  50  not to operate the load switch  301  by detecting the output control signal of the LED power prime circuit  10 . When the load  20  is short-circuited, the circuit detecting module  40  outputs a controlling signal for controlling the control switch module  50  to turn off the load switch  301  so as to turn off the whole circuit. The circuit detecting module  40  is configured for detecting the change of the output voltage of the LED power prime circuit  10 . When the load  20  is short-circuited, the output voltage of the LED power prime circuit  10  will be immediately decreased. Therefore, when the output voltage of the LED power prime circuit  10  is decreased, the circuit detecting module  40  can detect the drop of the output voltage and outputs the controlling signal right now. In the present embodiment, when the input voltage of the circuit detecting module  40  is less than 88% of the normal voltage at the output terminal of the LED power prime circuit  10 , the circuit detecting module  40  will output the controlling signal so as to turn off the load switch  301 . It can be understood that the size of the ratio may be adjusted by setting the parameter of the electronic component of the circuit detecting module  40 . For example, when the input voltage of the circuit detecting module  40  is less than such as 90% or 95%, it will output the controlling signal. The circuit detecting module  40  includes a comparing detecting unit  41  and a time delay unit  42 . The comparing detecting unit  41  is configured for comparing the output voltage of the LED power prime circuit  10  with a predetermined reference voltage and outputs a control signal. The comparing detecting unit  41  includes a reference voltage setting unit  411 , an output-voltage detecting unit  412 , and a comparing unit  413 . The comparing unit  413  may include an amplifier and the non-inverting input terminal of the amplifier is electrically connected to the output terminal of the reference voltage setting unit  411 , the inverting input terminal thereof is electrically connected to the output terminal of the output-voltage detecting unit  412 . The reference voltage setting unit  411  includes two resisters R 6  and R 10  electrically connected in series between the output terminal of the LED power prime circuit  10  and ground. The preset reference voltage of the reference voltage setting unit  411  can be set by setting the parameter of the two resistors R 6  and R 10 . The output-voltage detecting unit  412  is arranged in parallel with the reference voltage setting unit  411  and includes two resisters R 11 , R 14  electrically connected in series between the output terminal of the LED power prime circuit  10  and ground, and capacitor C 7  electrically connected in parallel with one of the two resisters R 11 , R 14 . In the circuit detecting module  40 , the output-voltage detecting unit  412  is configured for detecting the change of the output voltage of the LED power prime circuit  10 . In the present embodiment, when the output voltage of the output-voltage detecting unit  412  is less than 88% of the normal voltage of the output terminals of the LED power prime circuit  10 , the comparing unit  413  will output high level so as to drive the control switch module  50  to turn off the load switch  301 . The comparing unit  413  is a common electronic component, and in the present embodiment, the comparing unit  413  is a voltage comparator which determines that the output voltage thereof is a low level or a high level by comparing the input voltage of the non-inverting input terminal and the inverting input terminal. In the present embodiment, when the load  20  is normal condition, the output voltage of the LED power prime circuit  10  and the output voltage of the output-voltage detecting unit  412  is larger than the reference voltage set by the reference voltage setting unit  411  and the output voltage of the comparing unit  43  is high level. However, when short circuit occurs in the load  20 , the output voltage of the LED power prime circuit  10  is immediately lowered and when the output voltage of the LED power prime circuit  10  is smaller than 88% of the normal output voltage, the output voltage of the output-voltage detecting unit  412  will be smaller than the reference voltage, and the output voltage of the comparing unit  43  is low level. 
         [0017]    The time delay unit  42  is configured for extending the time period in that the low level signal reaches the control switch module  50  so as to achieve the purpose of effectively turning off the load switch  301  when the output voltage of the comparing detecting unit  42  is low level. If the time period has not been extended, when the output voltage of the LED power prime circuit  10  is lowered without the delay of the time delay unit  42 , the load switch  301  is turned off right now and the output voltage of the LED power prime circuit  10  returns to the normal level, almost at the same time the load switch  301  will be turned on. As a result, the load switch  301  will be turned on or turned off at a very high frequency under the control of the comparing detecting unit  41 . Therefore, the load switch  301  will be burnt, particularly when the load switch  301  is a MOS tube. When the time delay unit  42  extends the low level signal to the control switch module  50  for  1  second, the N-channel MOS Q 7  has sufficient turn-off time to dissipate heat without burning. The time delay unit  42  includes a delay comparator  421 , a voltage divider resister group  422 , and an RC charge/discharge circuit  423 . The output terminal of the comparing detecting unit  41  is electrically connected to the inverting input end of the delay comparator  421  and the non-inverting input end of the delay comparator  421  is electrically connected to the output terminal of the voltage divider resister group  422 . The RC charge/discharge circuit  423  includes a capacitor C 8  electrically connected between the inverting input end of the delay comparator  421  and the output terminal of the delay comparator  421 , and a resister R 12  electrically connected between the output terminal of the comparing detecting unit  41  and ground. When the output voltage of the comparing detecting unit  41  is high level, the voltage of the non-inverting input end of the delay comparator  421  is higher than that of the inverting input end and the output voltage of the delay comparator  421  is high level and the capacitor C 8  will be charged. When the output of comparing detecting unit  41  is low level, the voltage of the inverting input end of the delay comparator  421  is lower than that of the non-inverting input end and the output of the delay comparator  421  and the capacitor C 8  will be discharged so as to prevent the immediate output of the low level signal of the time delay unit  42 . However, when the discharge of the capacitor C 8  is finished, the time delay unit  42  outputs the low level signal, thereby achieving the purpose of delay. 
         [0018]    The control switch module  50  may include an NPN-typed triode Q 10 . It can be understood that other types of electronic components or circuit may be used as the control switch module  50 , as long as it can be turned on when the time delay unit  42  outputs low level and can be turned off when it outputs high level. A base of the NPN-typed triode Q 10  is electrically connected to the output terminal of the time delay unit  42 , A collector is electrically connected to the load switch  301 , and A emitter grounds. When the time delay unit  42  outputs low level, the NPN-typed triode Q 10  turns on ground, the load switch  301 , i.e., the gate of the MOS transistor Q 7 , is low level so that the MOS transistor Q 7  is turned off to achieve the purpose of turning off the load switch  301 . However, when the time delay unit outputs high level, the NPN-typed triode Q 10  turns off, and the gate of the MOS Q 7  is high level and turns on. 
         [0019]    The power supply circuit  100  for LED lighting protects the short circuit protection switch module  30  by the comparing detecting unit  41  and the time delay unit  42  so as to turn off the whole circuit when short circuit occurs in the load  20 . Moreover, the power supply circuit  100  for LED lighting protects the load switch  301  of the short circuit protection switch module  30  from burning so as to avoid the whole circuit from failing. 
         [0020]    While the disclosure has been described by way of example and in terms of exemplary embodiment, it is to be understood that the disclosure is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.