Bridge converter and method of controlling the same

A bridge converter, configured to convert an input voltage for providing an output voltage to a load, comprising:

• a switching circuit comprising a first bridge arm wherein the first bridge arm comprises a first switch and a second switch connected in series;
• a rectifying circuit configured to be coupled to the load;
• a transformer comprising a primary side coupled to the switching circuit and a secondary side coupled to the rectifying circuit;
• a control unit providing a first control signal and a second control signal for respectively controlling the first switch and the second switch based on the output voltage;
• and
• a drive module coupled to the control unit and the switching circuit for driving the switching circuit to converting the input voltage;
• wherein when a loading of the load is lower than a predetermined level, the control unit fixes operation frequencies of the first control signal and the second control signal at a maximum frequency, controls the drive module to drive the first switch and the second switch respectively according to the first control signal and the second control signal in a first time period, and disables the drive module to not drive the first switch and the second switch in a second time period;
• wherein the switching circuit is configured to be coupled to a capacitor;
• the control unit controls the drive module and the switching circuit to charge the capacitor in the first time period and controls the drive module and the switching circuit not to charge the capacitor in the second time period;
• and the control module determines the second time period to be less than or equal to a maximum time period determined based on a capacitance of the capacitor.