Design Of Nano-diamond FED Driving Circuit

Field emission displays (FED) have become a hot study field currently, which integrates the advantages of cathode ray tube (CRT) display and other flat panel display. With excellent physical and chemical properties, diamond has been regarded as one of the potential field emission cathode materials. While the study of driving circuits matching with them is a major marketization prerequisite of diamond FED.Based on the experimental research of nano-diamond field emission cathode as well as the driving principle analysis of 3 inch FED, the basic circuit parameters which met the requirements of driving circuits have been determined, such as electron emission threshold voltage, stability launch electronic voltage and emission current.The logic driving circuits controlled by assembly language have been designed based on the 74HC154, 74HC595 and other digital chips, with AT89S51 MCU as logic control core.Two high-voltage circuits have been designed: voltage doubling rectifying circuit and fly-back switching high-voltage power supply circuit. In the voltage doubling rectifying circuit, the high voltage has been realized by the positive and negative way, and the voltage between the cathode and anode could reach 1700 V. In the fly-back switching high-voltage power supply, considering the requirements of each unit of the driving circuits on the power supply, the three-group voltage outputs including low-voltage outputs have been realized: 1600V/20mA,12V/500mA, 5V/50mA, in which UC3842 has been used to achieve pulse width modulation. Several commonly FED gradation modulation methods have been introduced, and the emphasis has been put on the analysis and realization of the gray modulation using pulse width modulation method.The circuits have been simulated by Multisim10.0 software. The PCB boards have been drawn out and the sample circuits have been constructed. The FED logic functions have been certified based on 16×16 LED matrix.