Overvoltage protection system and method for LED lighting

The invention relates to an overvoltage protection system and method for LED lighting, and provides a system controller and method for a power converter. For example, the system controller used for the power converter comprises a logic controller generating modulation signals, and a driver receiving the modulation signals. The driver generates driving signals at least partially based on modulation signals and output the driving signals to the switch so as to affect current flowing through an inductance winding of the power converter. In addition, the system controller comprises a voltage-to-voltage converter receiving a first voltage signal, modulation signals and demagnetization signals, and the voltage-to-voltage converter generates a second voltage signal at least partially based on the first voltage signal, the modulation signals and the demagnetization signals.