Examples described herein relate to a power management system. The power management system may include an input power filter coupled between a common power bus having a first voltage level and a load. The input power filter may include a variable impedance circuit coupled to an input capacitor. Further, the power management system may include a bus voltage controller coupled to the input power filter to detect a transient event causing a surge in a load current drawn by the load and to alter an impedance of the variable impedance circuit to limit an input current flowing via the variable impedance circuit, thereby maintaining voltage on the common power bus within a predefined range from the first voltage level.