a normal minimum on-time module configured to output a first pulse signal based on a control signal for a transistor switch, wherein a pulse width of the first pulse signal is equal to a length of a normal minimum on-time of the transistor switch;

an extended minimum on-time module configured to output a second pulse signal based on the control signal, wherein a pulse width of the second pulse signal is equal to a length of an extended minimum on-time of the transistor switch, and the length of the extended minimum on-time is greater than the length of the normal minimum on-time;

a selection module comprising an input terminal coupled to the normal minimum on-time module and the extended minimum on-time module and an output terminal coupled to a gate of the transistor switch, the selection module configured to select one of the first and second pulse signals and provide it at the gate of the transistor switch; and

a control module comprising an output terminal coupled to a control terminal of the selection module, the control module configured to cause the selection module to select and output the second pulse signal under a certain condition where there is a need for current detection within the minimum on-time of the transistor switch and to select and output the first pulse signal under any other condition except the certain condition.