The embodiment just exemplifies the present invention and is not intended to limit the scope of the present invention; any equivalent modification and variation according to the spirit of the present invention is to be also included within the scope of the following claims and their equivalents.

It is worthy to point out that most currently available portable lighting devices have short-circuit protection mechanisms, such as fuses, comparator lockout protection s with amplifiers, and resettable fuses. However, these short-circuit protection mechanisms still have many shortcomings, so these short-circuit protection mechanisms need to be further improved. On the contrary, according to one embodiment of the present invention, the lighting device includes a resettable over-current protection circuit, which can function as a self-locking over-current protection circuit to execute a self-locking protection mode for providing the over-current protection function. When the fault is resolved, simply reconnecting the power supplying module can automatically turn off the self-locking protection mode to prevent fault expansion and avoid that the lighting device is damaged.

Also, according to one embodiment of the present invention, the resettable over-current protection circuit can be applied to most portable lighting devices and can effectively execute the self-locking protection mode to provide the over-current protection function without being limited by the duty cycle of pulse width modulation (PWM) signals. Additionally, the resettable over-current protection circuit can prevent the lighting device from repeatedly restarting. Therefore, the application of the resettable over-current protection circuit can be more comprehensive and significantly enhances the safety of the lighting device.