Research And Design Of A DC/DC Switching Power Supply Based On Soft Switching Technology

DC/DC switching power supply,as one of the main devices that provide DC voltage in the power system,faces many requirements,such as smaller size,lighter weight,higher frequency and higher efficiency.While increasing the switching frequency,it is necessary to reduce the switching loss to improve the energy conversion efficiency of the converter.One of the methods to reduce the switching loss is to realize the soft switching of the switch tube.Therefore,the study of DC/DC switching power supply based on soft switching technology has important practical significance.The thesis first briefly introduces the research background and development history of soft switching technology.Then it explains some basic theoretical knowledge of DC/DC switching power supply based on soft switching technology.It mainly includes the basic concepts of zero current resonant switch and zero voltage resonant switch,the circuit structure of zero voltage switching quasi-resonant converter,working principle,parameter design,voltage conversion ratio,control strategy and circuit topology selection,and several modulations of switch controller mode.Subsequently,the analysis and design of the overall circuit of the controller chip are explained,mainly including the design indicators of the chip,the overall structure,the pin design and typical applications.Then analyzed and simulated the core module circuit of the controller chip,which mainly included the fault circuit module,the soft reference circuit module,the voltage controlled oscillator module,the zero-crossing detection comparator and the monostable pulse generator module,and the control logic circuit module..Next,the overall circuit of the system was simulated and verified.Finally,it is layout design and packaging testing.Based on the Shanghai Advanced Semiconductor(ASMC)4 μm/40 V Bipolar process,this paper designs and fabricates a pulse frequency modulation(Pulse Frequency Modulation,PFM)type quasi-resonant controller,and completes the chip design and simulation verification(Spectre Platform),layout design,tape-out and corresponding functional testing.The chip’s reference voltage is 5 V(accuracy is 1%),the restart delay time is programmable,the frequency adjustment range is 10 k Hz to 1 MHz(programmable),and it can output two switching tube drive signals with a peak current of 1 A.Based on this controller chip,a DC/DC switching power supply based on soft switching technology was designed,and the corresponding system simulation and verification work was completed.Among them,the overall circuit of the system is formed by adding resonant inductors and resonant capacitors on the basis of the traditional boost topology.