Patent ID: 8284534

Claim:
An over-current protection circuit, comprising: a current input for receiving a input current; a current output electrically connectable to a load, for outputting an output current proportional to the input current; a switch connecting the current input to the current output, said switch having at least two switch states, said switch states including an open state in which a current flow from the current input to the current output is interrupted and a closed state in which said current flow is enabled, said switch including a switch control input for controlling the switch state; a sensor for sensing a load current applied to said load; a controller connected to the sensor for controlling said switch to be in said open state when said sensed load current has exceeded a current threshold during a predetermined period of time, said predetermined period of time being dependent on an amount with which said sensed load current exceeds the threshold, said controller including: a current comparator connected to said sensor, for comparing the sensed load current with a current threshold; a timer connected to said current comparator, for measuring a period of time the sensed load current exceeds said current threshold; and a time comparator connected to said timer, for comparing the measured period of time with a timer threshold and outputting a switch open signal when said measured period of time exceeds said timer threshold; and a time controller for controlling said timer or said timer threshold such that the period of time is shorted when an amount of sensed load current increases and the period of time is increased when said amount of sensed load current decreases, said time controller being connected to said current comparator for receiving information about said amount of sensed load current.