Fast Load Transient Response DC/DC Converters With Auxiliary Series Voltage Sources

Ultra-high-speed precision electronic devices,such as microprocessors,communication devices and computers,have very high requirements for the transient response characteristics of low-voltage high-current DC/DC converters,which currently exceed 20 m V/?s(dynamic voltage/regulation time).Regarding to this technical challenge,this paper explores the dynamic performance improvement technology based on power topology and control strategy combined regulation.When the load steps down,the auxiliary voltage source is connected in series to improve the fall slew rate of inductor current.Meanwhile,the capacitor charge balance adjustment scheme is used to realize the optimal load transient regulation of low-voltage high-current DC/DC converters.Moreover,the switching controller composed of steady-state control and capacitor charge balance dynamic control is used to ensure the good steady-state performance of the load transient optimal DC/DC converter.The main contents and research results are as follows:(1)An input voltage source series type single-phase Buck converter is proposed.Aiming at the problem that the transient response of DC/DC converter can not meet the actual demand,a single-phase Buck converter combining input voltage source series and capacitor charge balance control is proposed.The input voltage source series circuit improve the fall slew rate of inductor current,and the capacitor charge balance controller ensures the optimal load transient regulation of the improved Buck converter.The capacitor current hysteresis controller is used in the steady-state to ensure the good steady-state performance of the converter.Moreover,the implementation scheme of the input voltage source series circuit is given.The capacitor current hysteresis controller and capacitor charge balance controller are designed.Finally,the effectiveness and feasibility of the proposed Buck is verified by simulations and experimental results.(2)A single-phase Buck converter with auxiliary capacitor series is proposed.In order to further improve the fall slew rate of inductor current,an auxiliary capacitor series method is proposed.In auxiliary capacitor series method,the additional capacitor is connected in series to the above-mentioned series input voltage source circuit.This method makes the voltage source series method more general and the auxiliary voltage source is no longer limited to the input voltage source.The design principle of the auxiliary capacitor circuit is given and the capacitor charge balance control in two transient case is derived.Moreover,the implementation scheme of the proposed converter system is given.Finally,the simulations and experimental results show that the proposed scheme further improves the dynamic performance of the single-phase Buck converter system.(3)A multiphase Buck converter with input voltage source series is explored.For applications with very large currents,the low-voltage high-current DC/DC converters are mainly multi-phase Buck converters.Therefore,the proposed voltage source series method is extended to multi-phase Buck converters and the principle of the multiphase Buck converter with auxiliary series input voltage source is discussed.In order to facilitate the realization,the two-phase Buck converter is taken as the research object.The average current sharing steady-state controller is designed and the realization scheme of the proposed two-phase Buck converters is given.Finally,the simulations and experimental results show the effectiveness and feasibility of the proposed scheme in the multiphase Buck converters.