Method for Protecting a Semiconductor Switch, Protective Device for a Semiconductor Switch, and Control Circuit for a Semiconductor Switch

An activation circuit for a semiconductor switch (1), comprising:

• a driver stage (20), with an output terminal and at least one input terminal, which is designed to provide a control signal for the semiconductor switch (1) at the output terminal as a function of an input signal provided at the input terminal;
• an overvoltage detector (11), which is electrically coupled to an output of the semiconductor switch (1), and which is configured to provide an overvoltage signal when an electrical voltage at the output of the semiconductor switch (1) exceeds a predetermined threshold value;
• a limiting element (13), which is configured to limit the overvoltage signal supplied by the overvoltage detector (11) to a predetermined period of time and to provide the temporally limited overvoltage signal at an output terminal of the limiting element (13);
• an activation circuit (12), which is configured to enable an electrical connection between the overvoltage detector (11) and the limiting element (13) if a predetermined control signal is present at an input of the driver stage (20) for the semiconductor switch (1);
• and
• a compensation circuit (14), which is electrically coupled to the output terminal of the limiting element (13) and which is configured to provide a compensation signal at an input of the driver stage (20) for the semiconductor switch (1) as a function of the overvoltage signal that is temporally limited by the limiting element (13).

A method for protecting a semiconductor switch (1), which can be controlled by a driver stage (20), the method comprising:

• providing (S1) an overvoltage signal if a predetermined voltage is exceeded at a terminal of the semiconductor switch (1);
• detecting (S2) a predetermined control signal at an input of the driver stage (20);
• enabling (S3) the overvoltage signal if the predetermined control signal is detected at an input of the driver stage (20);
• limiting (S4) the enabled overvoltage signal to a maximum duration;
• providing (S5) a compensation signal at the input terminal of the driver stage (20) for the semiconductor switch (1), as a function of the temporally limited overvoltage signal.