Protection device for a semiconductor switch, and method for operating a protection device for a semiconductor switch
AssigneeRobert Bosch GmbH
InventorsSebastian Laich, Peter Sinn
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Abstract
The invention relates to a surge protection device for a semiconductor switch with an improved response behavior. The protection device comprises a dynamic component together with a static component and a capability to analyze switch operations on the semiconductor switch. The dynamic component of the surge protection device activates in the event of a low surge, but is time-limited, however, with respect to the response behavior. Furthermore, the response of the dynamic component of the surge protection device can also be limited such that a response occurs only after switch operations on the semiconductor switch.
Claims13
A protection device for protecting a semiconductor switch against a voltage surge, the protection device comprising:
- a driver configured to provide control signals to the semiconductor switch;
- a first surge protection circuit configured to actuate the semiconductor switch for a predetermined time period if a voltage at the semiconductor switch exceeds a first threshold value, wherein the first surge protection circuit includes a first semiconductor element that reversibly passes over from a blocking state into a conductive state;
- and
- a second surge protection circuit configured to actuate the semiconductor switch if the voltage at the semiconductor switch exceeds a second threshold value, wherein the second surge protection circuit includes a second semiconductor element that reversibly passes over from a blocking state into a conductive state,
- wherein the first surge protection circuit includes a first transistor configured to open when the first semiconductor element starts conducting, and wherein the second surge protection circuit includes a second transistor configured to open when the second semiconductor element starts conducting.
A method for operating a protection circuit for protecting a semiconductor switch against a voltage surge, comprising the following steps:
- detecting, with a switch detector, a switch operation at the semiconductor switch;
- actuating, with a first surge protection circuit, the semiconductor switch for a predetermined time period if the voltage at the semiconductor switch exceeds a first threshold value, the first surge protection circuit including a first semiconductor element that reversibly passes over from a blocking state into a conductive state;
- and
- actuating, with a second surge protection circuit, the semiconductor switch as long as the voltage at the semiconductor switch exceeds a second threshold value, the second surge protection circuit including a second semiconductor element that reversibly passes over from a blocking state into a conductive state,
- wherein the first surge protection circuit includes a first transistor configured to open when the first semiconductor element starts conducting, and wherein the second surge protection circuit includes a second transistor configured to open when the second semiconductor element starts conducting.
Dependencies are inferred from the claim text.