Patent ID: 7813095

Claim:
A system comprising: a live backplane adapted to provide a backplane voltage to one or more circuit cards connected thereto; and at least one protected circuit card adapted to couple to the live backplane, the protected circuit card including a discrete protection circuit adapted to limit the current provided to the protected circuit card when an input of the protected circuit card is coupled to the backplane voltage, the discrete protection circuit comprising: a first capacitor coupled to the input of the protected circuit card and adapted to accumulate a charge accordingly; a sense resistor adapted to sense a load current and have a voltage proportional to the load current so that an overcurrent condition can be detected by sensing the voltage across the sense resistor; a switch adapted to control the load current delivered to an output port; a discrete SCR adapted to latch when an overcurrent condition is detected, thereby preventing the flow of the load current to the output port; and a series of resistors coupled between the input of the protected circuit card and ground, the series of resistors adapted to set a charge time for the first capacitor, the charge time controlling the retry delay subsequent to the detection of an overcurrent condition.