| Inorganic electroluminescent(EL)devices are flexible,thin,bendable,with long average life,uniform light and good impact resistance;they are commonly used in decorative lighting and bright advertising signs,their simple structure and little heat disspasion,it is often called cold light line or cold light sheet.The EL devices behave as a capacitive load,which cause the transistor in the AC driver switching circuit to have a large peak current at the moment of opening and are easy to be burned down.The driver reliability is difficult to ensure.This paper mainly focuses on the current existing problems of EL light-emitting devices,from the EL surface light source drive circuit design,line light source drive circuit design and line light source graphic processing of the three aspects of the research design,the main research work are as follows.1.A half-bridge switching circuit is used as the design of the EL line light source driver program.According to the electrical characteristics of EL line light source itself and low power characteristics,the driver is relatively simple and easy to carry.The circuit adds a push-pull boost circuit,you can use a portable power supply to the line light source drive circuit power supply,and then with the control switch circuit,forming a more complete small power driver design program.2.The production of light-emitting patterns with EL light without plate making customization is convenient and cost-effective,for this reason,the use of laser cutting machine along the pattern line groove to fix the light,the successful decoding of the data format of the laser cutting machine node coordinates.A program was developed to automatically generate the specified equally spaced parallel cutting line,to ensure that the processing groove width and the same diameter of the light in order to quickly embed the light,eliminating the need for gluing to improve the appearance and significantly improve the production efficiency.3.A composite half-bridge switching circuit driver based on EL surface light source was designed.The large transient current capacity of thyristors(SCRs)was used as main switching transistors to driver circuit,in its anode-cathode ends in parallel with MOSFETs delayed on/off,to play the role of shorting the silicon controlled and current shunt,so that the silicon controlled can be turned off after opening.The MOSFETs delay switching time was properly adjusted to stagger the peak current so that the temperature rise of the two switching transistors equal or similar to further improve the reliability of this SCRMOSFETs composite switching circuit,the input/output power efficiency of this circuit is about 85%.In addition,drive this type of capacitive load to meet the large instantaneous power requirements of the switching power supply,it was widely used in radar,electronic warfare and other systems. |
