Research And Design Of High Frequency Fast Response Buck DC-DC Converter

Buck converters are widely used for their high efficiency and flexibility of output voltage.As the performance of application processors in mobile portable devices increases,the requirements for Buck converters are also increasing.Fast load response and high integration have gradually become research hotspots in the industry and academia.Therefore,this thesis proposes a high frequency and fast response Buck converter.Focusing on the studying in the system topology and control strategy,the thesis uses a hysteresis control suitable for fast response,whose inherent defects of the unstable operating frequency and low load regulation are solved.At the same time,the design of the main comparator in the loop is studied and a fast continuous-comparator is proposed.Combined with the system,it can meet the demand of 50MHz operating frequency.In order to realize the fast response of jump load,the thesis also designs a special assistant circuit to further increase the response gain of the duty cycle to the output voltage drop,so that the inductor current can be quickly increased to supply the changed load current.Aiming at the problem of efficiency in high frequencies,the dead time loss is researched and optimized.By the delay-locked loop based on the idea of phase-locked loop,the dead time established by traditional cycle-by-cycle is reduced,and removes some of the redundant dead time is removed,and the overall efficiency of the system is improvedThe input voltage range of the designed Buck converter is 3.3V-5.5V,the output voltage is 1.8V,the maximum output current is 1A,the operating frequency is 50MHz,the used inductor is 50nH,each of the input and output capacitance is only 2?F.The chip is designed by using the Global Foundries 0.18?m BCD(Bipolar CMOS DMOS)process.The simulation results show that the system can work stably at a working frequency of 50MHz.In the steady states,the output voltage ripple is within 1%of the output voltage.The response speed of the system meets the design requirements when the load jumps at a speed of 500mA/ns.Under typical working conditions,the peak efficiency reaches 82%,which is in line with design expectations...