Low power reduction Electrical Engineering - Essay Example

However, the key low-power breakthrough was the invention of the complementary metal-oxide-semiconductor (CMOS) integrated circuit in 1963. Most integrated circuits, especially low-power ICs, use CMOS devices as their building blocks. The smaller the power dissipation of electronic systems, the lower the heat pumped into the rooms, the lower the electricity consumed and hence the lower the impact on global environment, the less the office noise (due to elimination of a fan from the desktop), and the less stringent the environment/office power delivery or heat removal requirements.

The motivations for reducing power consumption differ from application to application. In the class of micro-powered battery-operated, portable applications, such as cellular phones and personal digital assistants, the goal is to keep the battery lifetime and weight reasonable and the packaging cost low. Power levels below 1-2 W, for instance, enable the use of inexpensive plastic packages. For high performance, portable computers, such as laptop and notebook computers, the goal is to reduce the power dissipation of the electronics portion of the system to a point, which is about half of the total power dissipation (including that of display and hard disk).

Finally, for high performance, non battery operated systems, such as workstations, set-top computers and multimedia digital signal processors, the overall goal of power minimization is to reduce system cost (cooling, packaging and energy bill) while ensuring long-term device reliability.Driving Factors.A crucial driving factor is that excessive power consumption is becoming the limiting factor in integrating more transistors on a single chip or on a multiple-chip module. Unless power consumption is dramatically reduced, the resulting heat will limit the feasible packing and performance of VLSI circuits and systems.

Consequently, there is also a clear financial advantage to reducing the power consumed in high performance systems. In addition to cost, there is the issue of reliability. High power systems often run hot, and high temperature tends to exacerbate several silicon failure mechanisms. Every 10-C increase in operating temperature roughly doubles a component's failure rate. In this context, peak power (maximum possible power dissipation) is a critical design factor as it determines the thermal and electrical limits of designs, impacts the system cost, size and weight, dictates specific battery type, component and system packaging and heat sinks, and aggravates the resistive and inductive voltage drop problems.

It is therefore essential to have the peak power under control.Achieving low Resistance. [[ The low resistance is achieved through appropriate metallic films on the IC with copper being the preferred material because, other than silver, it has the lowest resistance of any metal. The capacitance issue is addressed through the use of insulators with lower dielectric constants than silicon dioxide, the material of choice in the past. The switch has non-zero "on" resistance, Ron, when it is closed and finite "off" resistance, R off, when it is open.

This has important implications for low power operation, because R on leads to power dissipation in