An augmented hysteresis-controlled buck converter with improved transient performance

摘要

The paper has presented a new augmented buck converter to improve its transient performance. At first, an augmentation circuit based on diode-capacitor topology is introduced. The voltage across the inductor can be increased during load transients, and the rate of inductor current can be higher compared with conventional buck converters. Then, a hysteresis control algorithm based on output voltage is introduced to switch the operation modes during load transients. The detailed derivations of the upper threshold and the lower threshold are given. Actually, it's significant to select a reasonable value of the lower threshold. Otherwise, it will extend settling time during load transients. At last, the simulations and experiments are conducted to verify the functionality of the proposed converter. The results show that it can be applied for improving heavy-to-light load transient response as well as light-to-heavy load transient response. The output capacitance can be reduced by using the proposed converter. Furthermore, it can reduce the adverse effect of input voltage fluctuations due to the parallel connection of input capacitors. It is preferred when load transients and input voltage fluctuations occur frequently.