A power supply circuit for receiving an input voltage to drive a plurality of loads is disclosed. The power supply circuit comprises a plurality of switch circuits, a plurality of power conversion circuits and a phase delay circuit. The plurality of switch circuits are connected with the plurality of loads, respectively. The plurality of power conversion circuits are connected with the plurality of loads and the plurality of switch circuits, respectively, for converting the input voltage into a plurality of driving voltages and transmitting the plurality of driving voltages to the plurality of loads, respectively, when the plurality of switch circuits are conducted. The phase delay circuit is connected with the plurality of switch circuits and a system circuit for generating a plurality of delay signals in response to a switch signal from the system circuit and transmitting the plurality of delay signals to control terminals of the plurality of switch circuits, respectively, so as to make the plurality of switch circuits be conducted or shut off. The plurality of delay signals are converted into an enabling status from a disabling status at different time points so that the plurality of switch circuits are conducted at different time points.