Converter and converting method thereof

A converter, comprising:

• a transformer, having a first side and a second side;
• a first switching circuit, coupled to the first side of the transformer, the first switching circuit being controlled by a first driving signal to transfer power to the transformer during a first enabling period;
• a second switching circuit, coupled to the second side of the transformer, the second switching circuit being controlled by a second driving signal to transfer power received from the transformer;
• a controller, configured to provide the first driving signal to the first switching circuit, provide the second driving signal to the second switching circuit, generate the second driving signal according to the first driving signal of a same driving period, and enable a second enabling period of the second driving signal during the same driving period;
• and
• a sensing circuit, coupled to the transformer and the controller, wherein the sensing circuit is configured to sense a current flowing through the second side of the transformer to generate a sensing signal, wherein the controller is configured to enable the second enabling period of the second driving signal after determining that the sensing signal is greater than a first predetermined threshold,
• wherein after the controller enables the second enabling period of the second driving signal the controller is further configured to disable the second driving signal after determining that the sensing signal is less than a second predetermined threshold, and the first predetermined threshold is greater than the second predetermined threshold,
• wherein the controller further comprises a hysteresis comparator, coupled to the sensing circuit, wherein the hysteresis comparator is configured to compare the sensing signal with the first predetermined threshold and generate a first comparison signal and the hysteresis comparator is configured to compare the sensing signal with the second predetermined threshold and generate a second comparison signal,
• wherein when a rising edge of the first driving signal is detected, the controller enters an initial state and the controller sets the second driving signal to be disabled,
• in response to determining that the sensing signal is greater than the first predetermined threshold, the controller sets the second driving signal to be enabled, and
• in response to determining that the sensing signal is less than the second predetermined threshold, the controller sets the second driving signal to be disabled.