A power management circuit operable to reduce rush current is provided. The power management circuit is configured to provide a time-variant voltage(s) to a power amplifier(s) for amplifying a radio frequency (RF) signal(s). Notably, a variation in the time-variant voltage(s) can cause a rush current that is proportionally related to the variation of the time-variant voltage(s). To reduce the rush current, the power management circuit is configured to maintain the time-variant voltage(s) at a non-zero standby voltage level when the power amplifier(s) is inactive. When the power amplifier(s) becomes active and the time-variant voltage(s) needs to be raised or reduced from the non-zero standby voltage level, the rush current will be smaller as a result of reduced variation in the time-variant voltage(s). As such, it is possible to prolong the battery life in a device employing the power management circuit.