A switching power converter having a first and a second transistor are connected in series with the transformer to provide higher switching efficiency. A charge pump circuit is coupled to a drive circuit to provide a power source for driving the first transistor. A third transistor is connected between the transformer and the ground to help the switching of the transformer and the charge of the charge pump circuit. A switching control circuit is coupled to the output of the switching power converter to generate a first switching signal and a second switching signal for regulating the switching power converter. The first switching signal is coupled to drive the first transistor and the second transistor. The second switching signal is coupled to drive the third transistor.