A power management circuit includes a boost converter which generates a boosted voltage at a boosting node by boosting an input voltage by using a reference boosting voltage, a voltage regulator coupled to the boosting node and an output node, a bypass transistor coupled between the boosting node and the output node, and a regulator control block which compares the input voltage with a reference input voltage. When the input voltage is higher than or equal to the reference input voltage, the regulator control block increases the reference boosting voltage to increase the boosted voltage, enables the voltage regulator to generate a regulated voltage by regulating the increased boosted voltage, turns off the bypass transistor such that the regulated voltage is output as a pixel power supply voltage at the output node, and maintains an enable state of the voltage regulator for a minimum enable time.