Patent Publication Number: US-2015062888-A1

Title: Light emitting diode lamp using alternating current voltage

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0106050 filed in the Korean Intellectual Property Office on Sep. 4, 2013, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD  
     The present invention relates to a light emitting diode lamp, and more particularly to a light emitting diode lamp which can be used by being directly connected to ordinary alternating current voltage without using a switching mode power supply (SMPS) which is needed for operating a conventional light emitting diode lamp and is expensive. 
     BACKGROUND ART  
     A conventional fluorescent lamp is generally applied with alternating current of 90 to 1,500V (peak voltage) to emit light. On the other hand, a light emitting diode (LED) lamp is a device which can substitute such a conventional fluorescent lamp and a high intensity discharge lamp, and emits light by converting alternating current of high voltage inputted into a SMPS to direct current of less than 90V and applying the converted direct current to the LED lamp. As such, a conventional LED lamp emits light using the SMPS which is an electrical power device. 
     Since as such the LED lamp is a semiconductor which uses direct current, there are problems in life span and operation of the LED lamp if alternating current which is applied to a fluorescent lamp is applied to the LED lamp, and there may be risks such as breaking, explosion, or fire in case that the LED lamp is connected to a ballast for operating a fluorescent lamp. For this reason, in order to substitute a fluorescent lamp with an LED lamp, a ballast for a conventional fluorescent lamp is generally substituted with an SMPS for the LED lamp. Accordingly, cost for substitution work occurs and the expensive SMPS is used, overall cost increases. 
     In order to solve this problem, there is a necessity of lighting an LED lamp using alternating current of 90 to 250V without using an expensive SMPS. 
     A conventional LED lamp adopts a technology for converting alternating current of low voltage (generally AC 12-24V) or direct current (DC of less than 90V) into constant current for driving a light emitting diode. For example, a method of converting AC voltage into DC voltage using a bridge diode and adding a current regulating diode (CRD) or a resistor at the front end of a light emitting diode device to light a light emitting diode device has been known. This method can be advantageously used for a light emitting diode lamp of relatively lower voltage range of AC 12 to 24V, e.g., a lighting device for a vehicle using a battery of 12V. 
     However, an LED lamp for use in a house or an office may be broken or explode in a condition in which a minimum voltage is higher than AC 90V, and there may also be a problem of flickering. 
     Circuits which solve these problems and can operate an LED lamp with alternating current of higher than 90V are being developed. For example, if high voltage of higher than AC 90V is applied, a bridge diode coverts alternating current to direct current and constant current is generated via a constant current circuit using a transistor, and the generated constant current is applied to an LED device. 
     However, an LED lamp with such a circuit is useful as a technology which excludes an expensive SMPS, but it is difficult to be actually used because it has some problems. 
     Firstly, when voltage varies between AC 90 to 120V, output current (output of transistor constant current circuit) fluctuates a lot so that current applied to an LED device may rapidly change in response to voltage change, it is difficult to ensure the credibility of an LED device and there is a problem in that electric power consumption alters depending on conditions of applied voltages. Further, there is a flickering phenomenon that an LED lamp repeats ON and OFF in very short times may occur in a frequency range of about 50 Hz, so in such case users of an LED lamp may feel dizzy or eye strain. For these reasons, it is very difficult to actually apply this. 
     Secondly, since it does not have a circuit for compensating a power factor, it has a poor power factor and a poor light efficiency, and since a method for generating constant current is unstable so that although it is formed as 20 W level of the electric power consumption in a specific environment, i.e., in AC 220V, the electric power consumption may become above 27 W in a situation in which AC 225V is applied, so an LED lamp may be broken. 
     DETAILED DESCRIPTION OF THE INVENTION  
     Technical Problem  
     The present invention has been made in an effort to provide a light emitting diode lamp in which an expensive SMPS for an LED can be excluded, can stably and easily be used above AC 90V, flickering phenomenon can be minimized under the condition of frequency of 50 Hz, and has a circuit which can prevent problems of decrease of life span, malfunction, increase of electric power consumption, safety accident, or the like of an LED lamp which uses alternating current of high voltage (higher than AC 90V). 
     Concretely, the present invention has been made in an effort to provide a light emitting diode lamp which can be used with a ballast for a conventional fluorescent lamp using alternating current of higher AC 90V and can be directly used to alternating current of 100 to 250V without a ballast for a conventional fluorescent lamp. Accordingly, work for substituting a conventional lighting device with an LED lamp can be performed by only replacement of an LED lamp without additional work, and at the same time in case that the lift span of a ballast of a conventional fluorescent lamp expires, an LED lamp can remain to be used to an alternating current source only if a ballast is removed. 
     Technical Solution  
     A light emitting diode lamp according to an exemplary embodiment of the present invention includes: a pair of first pins which are electrically connected to one another; a pair of second pins which are electrically connected to one another; a light emitting diode device module having one or more light emitting diode devices; a bridge diode which is electrically connected to the first pins and the second pins so as to be applied with external alternating current via the first pins and the second pins and converts the applied alternating current to direct current and is connected to both ends of the light emitting diode device module so as to supply the converted direct current to the light emitting diode device module; and one or more inductors which are provided between at least one of the pair of the first pins and the pair of the second pins and the bridge diode. 
     The one or more inductors may include a first inductor which is electrically connected respectively to the pair of the first pins and the bridge diode and a second inductor which is electrically connected respectively to the pair of the second pins and the bridge diode. 
     The light emitting diode lamp may further include a condenser which is connected to the light emitting diode device module in parallel. 
     The light emitting diode lamp may further include an excessive voltage blocking element which is connected to the light emitting diode device module in parallel. 
     The light emitting diode lamp may further include a fuse which is connected to the light emitting diode device module. 
     The light emitting diode lamp may further include a ballast which is connected respectively to the pair of the first pins and the pair of the second pins. 
     The light emitting diode lamp may further include a pair of bases to which the pair of the first pins and the pair of the second pins are respectively connected, and the ballast may be mounted to one of the pair of the bases. 
     The light emitting diode lamp may further include a printed circuited board to which the light emitting diode device module is mounted, and the ballast may be mounted to the printed circuit board. 
     Advantageous Effects  
     According to the present invention, an LED lamp can be used by being directly connected to alternating current of 100 to 250V without a ballast, so that an expensive SMPS for an LED lamp can be excluded. 
     Further, since an LED lamp is manufactured separately from a ballast of a fluorescent lamp and various protection functions are provided, an LED lamp can be used by being directly connected to a ballast of a conventional fluorescent lamp and can be used by being directly connected to alternating current of 100 to 250V so that an expensive SMPS for an LED lamp can be excluded. 
     Further, since flickering phenomenon can be prevented or minimized under the condition of frequency of 50 Hz, it is possible to provide an LED lamp having a circuit which can prevent problems of decrease of life span, malfunction, increase of electric power consumption, safety accident, or the like of an LED lamp which uses alternating current of high voltage (for example, higher than AC 90V). 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS  
         FIG. 1  is a circuit diagram of a light emitting diode lamp according to an embodiment of the present invention. 
         FIG. 2  is a drawing showing an example in which a light emitting diode lamp according to an embodiment of the present invention is realized as a type of a fluorescent lamp. 
     
    
    
     DESCRIPTIONS OF REFERENCE NUMERALS 
       11 : first pin 
       13 : second pin 
       21 : first inductor 
       23 : second inductor 
       30 : light emitting diode device module 
       40 : bridge diode 
       50 : condenser 
       60 : excessive voltage blocking element 
       70 : fuse 
       100 : light transmitting cover 
       200 : base 
       300 : printed circuit board 
       400 : heat radiation member 
       610 : electrical terminal 
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
     Embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings. 
     A pair of first pins  11  and a pair of second pins  13  are provided. For example, as exemplarily shown in  FIG. 2 , in case that a light emitting diode lamp according to an embodiment of the present invention is realized as a type of a fluorescent lamp, the first pins  11  and the second pins  13  may be provided to be respectively protruded from bases  200  which are respectively coupled to both sides of a light transmitting cover  100 . 
     At this time, the pair of the first pins  11  are electrically connected to one another, and similarly the pair of the second pins  13  are also electrically connected to on another. 
     One or more inductors  21  and  23  may be disposed between at least one of the pair of the first pins  11  and the pair of the second pins  13  and a light emitting diode device module  30 . For example, referring to  FIG. 1 , the first inductor  21  is electrically connected to the pair of the first pins  11  which are electrically connected to one another, and the second inductor  23  is electrically connected to the pair of the second pins  13  which are electrically connected to one another. Although two inductors  21  and  23  are provided in  FIG. 1 , one of them may be omitted and the position thereof may also be varied. 
     The light emitting diode device module  30  includes one or more light emitting diode devices  31 . The light emitting diode device  31  may be a conventional light emitting diode device which emits light by being applied with direct current. 
     A bridge diode  40  is connected respectively to the first inductor  21  and the second inductor  23  so as to be applied with alternating current via the first pins  11  and the second pins  13 . Further, the bridge diode  40  is connected to both ends of the light emitting diode device module  30  such that alternating current applied via the first inductor  21  and the second inductor  23  is rectified to direct current type and is then supplied to the light emitting diode device module  30 . That is, the bridge diode  40  is electrically connected respectively to the first and the second inductors  21  and  23  and the light emitting diode device module  30  and rectifies external alternating current which is applied via the first and the second pins  11  and  13  into direct current type and then supplies the same to the light emitting diode device module  30 . Further, the bridge diode  40  plays a role of converting alternating current to be nonpolar in addition to a role of converting alternating current to direct current. The light emitting diode device  31  is operated by direct current supplied via the bridge diode  40  to emit light. 
     As is known in the art, the bridge diode  40  may be formed with four rectification diodes D 1 , D 2 , D 3  and D 4 , and description of the operation of the bridge diode  40  will be omitted. Although it is shown in the drawing that two rectification diodes D 1  and D 2  are disposed at the side toward the first pins  11  and the other two rectification diodes D 3  and D 4  are disposed to the side toward the second pins  13 , the four rectification diodes D 1 , D 2 , D 3  and D 4  are connected to one another to form one bridge diode  40 . 
     The light emitting diode lamp according to an embodiment of the present invention can be used by being connected directly to alternating current voltage (for example alternating current voltage of 90 to 250V) without using expensive SMPS by these configurations. 
     Meanwhile, as shown in  FIG. 1 , a condenser  50  may be connected to the light emitting diode device module  30  in parallel. The condenser  50  is connected to an input terminal and an output terminal of the light emitting diode device module  30  in parallel to play a role of preventing flickering of the light emitting diode lamp. 
     The inductors  21  and  23  which have been described above may play a role of compensating increase of phase difference of voltage and current which is caused by deterioration of power factor of a light emitting diode lamp due to the condenser  50  which is provided for preventing the flickering of the light emitting diode lamp. In addition, the inductors  21  and  23  may also play a role of stabilizing excessive current to constant current so as to make circuit stable. 
     Meanwhile, an excessive voltage blocking element  60  may be connected to the light emitting diode device module  30  in parallel. The excessive voltage blocking element  60  blocks large abnormal voltage from being applied to the light emitting diode device module  30  so as to protect the light emitting diode device  31 , and may be realized as a TVS diode, a Zener diode, a varistor or the like. For example, in case of occurrence of very large abnormal voltage, the abnormal voltage is bypassed through the excessive voltage blocking element  60  without being applied to the light emitting diode device module  30  so that the light emitting diode device  31  can be protected. 
     A fuse  70  may be connected to a light emitting diode device module  30 . The fuse  70  is a circuit stabilization element for protecting the light emitting diode device module  30 , and in case that this is provided together with the excessive voltage blocking element  60 , it can protect secondly the light emitting diode device module  30  in case that the excessive voltage blocking element  60  is destroyed. 
     Concrete configuration of the light emitting diode lamp according to an embodiment of the present invention will be described with reference to  FIG. 2 . 
     As shown in  FIG. 2 , the light emitting lamp may have shape of a conventional fluorescent lamp, and the bases  200  may be provided respectively to both sides of the light transmitting cover  100 , and the pair of the first pins  11  and the pair of the second pins  13  are respectively provided to both bases  200 . 
     The light emitting diode device  31  may be mounted on a printed circuit board  300 , and the inductors  21  and  23 , the bridge diode  40 , the condenser  50 , the excessive voltage blocking element  60 , the fuse  70 , and the like may also be mounted on the printed circuit board  300 . Further, a heat radiation member  400  may be coupled to a rear side of the light transmitting cover  100 , and the printed circuit board  300  is connected to the heat radiation member  400  so that heat generated in the light emitting diode device  31  can be effectively radiated. 
     Electrical terminals  610  for electrical connection with the first pins  11  may be provided at one end of the printed circuit board  300 . Meanwhile, not shown in the drawing, electrical terminals for electrical connection with the second pins  13  may be provided at the other end of the printed circuit board  300 . 
     The light emitting diode lamp having a shape of a conventional fluorescent lamp as shown in  FIG. 2  can be used by being directly connected to alternating current source. 
     Meanwhile, referring to  FIG. 1 , the light emitting diode lamp according to an embodiment of the present invention may further include a ballast  80 . Four terminals of the ballast  80  may be respectively connected to the pair of the first pins  11  and the pair of the second pins  13 . At this time, not shown in the drawing, the ballast  80  may be mounted to one of the bases  200  or to the printed circuit board  300 . 
     Since the ballast  80  is integrally provided to the light emitting diode lamp, the light emitting diode can be used by being connected to alternating current source like a conventional fluorescent lamp without an SMPS. 
     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.