Abstract: This apparatus and method controls and limits the flow of in-rush current and maintains a supply voltage to a peripheral device during power surges. The apparatus and method essentially isolate and limit in-rush current flow to an in-rush circuit comprising a capacitive load and series resistor connected directly to the power bus at one end and to a reference potential at the other end. A switching device is coupled to the series resistor. A current sensing circuit is coupled to the series resistor. During initial start-up or "hot plugging" of the device, a control circuit turns "off" the switching device causing the load to be charged from the power bus through the resistive device for a pre-selected time interval, after which the switching circuit is turned "on" to bypass the resistive device and connect the load and the peripheral device to the power bus.

Abstract: This apparatus and method controls and limits the flow of in-rush current to a peripheral device coupled to a main power supply unit through a power bus and a ground bus. The apparatus and method essentially isolate and limit in-rush current flow to a capacitive load until operational current flow occurs to the peripheral device. A switching device is coupled to the power bus and the ground bus through a load. A resistive device is coupled to the power bus and the ground bus through the load. A control circuit is connected to the switching device. During initial start-up or "hot plugging" of the device, the control circuit turns "off" the switching device causing the load to be charged from the power bus through the resistive device until a predetermined condition occurs whereupon the switching circuit is turned "on" to bypass the resistive device and connect the load and the peripheral device to the power bus.