Abstract: The driving circuit includes a power module, a plurality of LED modules, and a constant current component. Each LED module includes a bypass circuit and at least one light emitting diode. The light emitting diode is serially connected between a first end and a second end of the bypass circuit. The first end of each bypass circuit is coupled to the power module or a third end of an adjacent upstream bypass circuit for serially connecting the constant current component electrically, thereby achieving the illumination of different total numbers of LED units in accordance with various voltage changes, and cascade light emitting diodes having increased power efficiency.