A converter control circuit applicable to various topologies of converters each employing two switching devices is disclosed. The converter control circuit includes an oscillator for generating a pulse signal and triangle-wave signal of a certain frequency, a switching control signal output unit for outputting a switching control signal to control ON/OFF of a plurality of switching devices based on a duty ratio determined from a feedback signal which is applied to a feedback terminal, a mode select signal generator for generating a mode select signal for determination of a control mode of a converter in response to the feedback signal applied to the feedback terminal, and a mode selecting unit for selecting the control mode in response to the mode select signal.