System controller for a lighting system and method thereof according to certain embodiments. For example, the system controller includes a first controller terminal configured to receive a first signal and a transistor including a first transistor terminal, a second transistor terminal, and a third transistor terminal. Additionally, the system controller includes a second controller terminal coupled to the first transistor terminal, and a third controller terminal coupled to the third transistor terminal. The system controller is configured to determine whether the first signal is associated with a leading-edge TRIAC dimmer based at least in part on the first signal, the leading-edge TRIAC dimmer being configured to receive an AC input voltage associated with at least a first half cycle from a starting time to an ending time.