An electronic ballast includes an inductor, an output transformer, at least two switching elements, a control circuit, a clamping circuit, and at least two return circuits. The inductor is electrically coupled to a DC power supply. The control circuit is electrically connected to the inductor, the output transformer and the switching elements for controlling on/off statuses of the switching elements. The clamping circuit is electrically connected to the inductor, and limits a node voltage among the inductor, the control circuit, and the clamping circuit below a threshold value and generates an output current on condition that the node voltage is larger than the threshold value. Each of the return circuits is electrically connected to the clamping circuit and coupled to both terminals of one of the switching elements for transmitting the output current to the output transformer, thereby permitting a reverse voltage of the switching elements within a maximum allowable range of the switching elements.