An over-current protection device for a power generator includes a first pin, configured to receive a signal; a detection and control module, coupled to the first pin, and configured to detect the signal to determine whether the signal conforms to a pre-determined condition or not, and to output a control signal when the signal conforms to the pre-determined condition; and an auto-trim and memory module, coupled to the detection and control module, and configured to receive the control signal from the detection and control module for executing corresponding auto-trim measurements and storing corresponding adjustment data.