| 摘要 |
The invention relates to a multi-staged overvoltage protection circuit, in particular for information-technology systems, comprising at least one coarse protection element and at least one fine protection element, wherein the at least one fine protection element can be activated by a triggering device depending on a threshold. According to the invention, the applied operating voltage is led to an evaluation device, which generates a reference voltage. Also provided is an evaluation unit, firstly for checking to see whether the current operating voltage is above the reference voltage, secondly for checking to see whether the voltage excess exceeds a previously determined level, and thirdly for establishing whether the rate of change of the operating voltage is greater than another previously determined value so that a transient overvoltage exists, wherein the triggering device then receives an activation signal from the evaluation device. |
