Low-Power Technology for Image-Processing LSIs

摘要

The conventional LSI design assumed power would be supplied uniformly to all parts of an LSI.For a design with multiple supply voltages and a power gating design, the inside of an LSI must be divided into multiple supply regions, and this complicates the LSI design.This paper introduces low-power technology applied to image-processing LSIs of Fujitsu Semiconductor, which designs such complicated LSIs with high reliability.Fujitsu Semiconductor engages in intensive development with CoolAdjust, a set of technologies to reduce power consumption by controlling power supply.Accordingly, this paper mainly focuses on describing technologies for a design that can handle multiple supply voltages and effectively reduce the dynamic power, and a power gating design that can effectively reduce the amount of leakage power.In a power gating design, when the power switch is turned on to supply power to a circuit, a large current called an inrush current runs so as to charge the parasitic capacitance of the circuit.It is known that this inrush current affects the circuits that are already powered on.This problem has been solved by controlling two types of power switches with a time interval, and this is also presented here.