Heavy load requirements during start-up or a fast initial charging of bypass capacitors, bulk capacitors, and capacitance of the processor’s millions of transistors may result in an in-rush or surge current. Older FPGA power designs need to pay attention to in-rush currents, and there are several techniques to accommodate in-rush currents. Overdesigning the power supply is not the most practical, since it increases the size and cost to support the inrush current. Adding an external circuit by using a power FET and resistor-capacitor to slowly turn on the MOSFET is not much better, actually, since more board area is required and it may be difficult to add that circuit at the last minute of the design. However, using a power supply with a fixed start-up time, or better yet, an adjustable soft-start time, will slow down the start-up ramp and allow the capacitance to be charged properly.