Managing Power Electronics: VLSI and DSP-Driven Computer Systems

Chapter 7

Computing and Communications Systems

7.1 Power Management of Desktop and Notebook Computers

Power management of PCs is becoming an increasingly complex endeavor. Figure 7-1 shows the progression of Intel PC platforms, from the launch of the Pentium in 1996 to current times. The Pentium brand CPU opens up the modern era of computing however, the birth of the CPU goes back as far as 1971 to the Intel 4004 CPU. In Figure 7-1 below each Pentium generation and associated voltage regulator offered by Fairchild Semiconductors, we find the year of the platform launch, the voltage regulation protocol (VRMxxx), the minimum feature (minimum line width drawn) of the transistors at that juncture in micro-meters, and the current consumption of the CPU.

Before Pentium, CPUs required relatively low power and could be powered by linear regulators. With Pentium the power becomes high enough to require switching regulators, devices distinctively more efficient than linear regulators. With Pentium IV the power becomes too high to be handled by a single phase (1Φ)—just to grasp the concept, think of a single piston engine trying to power a car—regulator, and the era of interleaved multiphase regulation (the paralleling and time spacing of multiple regulators) begins. At the VRM10 juncture, the breath-taking pace of Moore's law has slowed down somewhat, as exemplified by the unusual longevity of this platform. At the VRM11 juncture, the rate of increase in CPU power consumption has been slowed ...