Patent ID: 8144444
Filing Date: 2012-03-27
Classification: G05F,H02H

Abstract:
1. A protection circuit for protecting an electronic circuit against EMC disturbances and/or negative transient overvoltage pulses, the protection circuit comprising: a first switch in series between a power supply and the electronic circuit, the first switch having a control terminal and first and second current carrying terminals; a comparator for comparing a first operating parameter with a DC signal and producing a comparison signal, the comparison signal being used as a control signal for controlling opening and closing of the first switch; a delay circuit that includes a second switch coupled for receiving the control signal and that generates an asymmetric delay and that is adapted for keeping the first switch open for a predetermined amount of time beyond the moment at which the comparison of the first operating parameter with the DC signal produces a comparison signal suitable for closing the first switch, and a level shifter having first, second, and third terminals, the first terminal coupled to the control terminal of the first switch and the second terminal coupled to the first terminal of the first switch, and the third terminal coupled to the delay circuit, wherein the level shifter shifts the voltage levels of output signals of the delay circuit so as to be able to control switching of the first switch.