ESD PROTECTION

摘要

A circuit for protecting a node (201) in an electronic device (200) from an electrostatic discharge comprising: a voltage rail (206) arranged to provide an predetermined voltage when the device is powered; a first switching device (202) connected between said node (201) and ground (204); a second switching device (203) coupled to said node (201) and arranged to control the conductance of the first switching device (202) between said node (201) and ground (204); wherein, the second switching device (203) is configured to, irrespective of whether the device is powered or not powered, (a) hold the conductance of the first switching device (202) low when the potential difference between the node (201) and the voltage rail (206) is within an operating range, and (b) hold the conductance of the first switching device (202) high in response to an overvoltage at the node (201) so as to allow current to flow from the node (201) to ground (204).