A Research On A Pseudo-random Frequency Jitter Technique Applied T DC/DC Converters

With the continuous advancement and development of science and technology,the semiconductor industry has also entered a period of rapid development in China.Switching power,as a very important part of the integrated circuit technology,needs more excellent performance.Especially with the rapid development of a series of electronic devices such as smart phones,tablets,artificial intelligence devices and virtual reality devices,the IC industry has made higher standards.At the same time,all kinds of highspeed electronic equipment against the electromagnetic interference are also increasing.Based on the above reasons,this paper studies the pseudo-random frequency jitter technology to suppress electromagnetic interference.Firstly,this paper introduces the background of switching power supply,and expounds the development trend of the whole industry.And then,this paper analyses the control principle of the switching power supply and the generation,propagation and suppression methods of EMI,based on these,the frequency jitter technology is selected to suppress the EMI.Next,this paper analyses and compares the principle and implementation method of frequency jitter technology,and put forward the design of pseudo-random frequency jitter technology.And then analyses all types of pseudo-random sequence generator.Next,this paper focuses on the principle analysis and simulation verification of each module inside the chip designed.At the end of the paper,we set up a system simulation circuit to simulate and verify the function.At the same time,this paper analyses the suppression effect of electromagnetic interference on the jitter range and jitter period.The pseudo-random frequency jitter technique can generate a pseudo-random sequence with a period of 1024.And the generated control signals through similar to the role of the decoder,can produce enough digits of control,and can reduce the EMI better.Based on the pseudo-random frequency jitter circuit designed in this paper,we analysis the output spectrum in different jitter cycles and different jitter range,and then we obtain the influence of pseudo-random frequency jitter technology on EMI.This paper uses the NEC's 0.35 ?m BCD process,and uses simulation tools such as Spectre,Hspice,and SPICE Explorer to simulate the various modules and the whole circuit of the chip.The simulation results show that the system can work normally,and all performances are good and meet the design requirements.The electromagnetic interference suppression effect is also very good.