Abstract: A driving controller, power conversion circuit, and method for modulating driving voltage level with respect to a load are disclosed. In which the method, controller and circuit are applied for modulating the driving voltage of a transistor in a power converter. The driving controller includes a load parameter measurement unit, a voltage modulation unit, and a driving control unit. In which the load parameter measurement unit detects a load parameter which represents the magnitude of the load of the power conversion circuit. The voltage modulation unit then modulates the potential level of the driving voltage of the transistors in response to the load parameter for reducing unnecessary power consumption associated with the transistors in the power converter and enhancing overall power efficiency of the power conversion circuit.