A control circuit for soft switching and synchronous rectifying is provided for power converter. A switching-signal circuit is used for generating drive signals and a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is developed for regulating the power converter. Drive signals are coupled to switch the power transformer. A propagation delay is developed between drive signals to achieve soft switching of the power converter. An isolation device is coupled to transfer the pulse signal from a primary side of a power transformer to a secondary side of the power transformer. A controller of the integrated synchronous rectifier is coupled to the secondary side of the power transformer for the rectifying operation. The controller is operated to receive the pulse signal for switching on/off the power transistor. The pulse signal is to set or reset a latch circuit of the controller for controlling the power transistor.