108 An Efficient Execution of Clock Gating Technique for Logic Circuits

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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 1 – MAY 2015 - ISSN: 2349 - 9303

An Efficient Execution of Clock Gating Technique for Logic Circuits S.Sri Kanchana Devi1

R.Rajalakshmi M.Tech2

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PG Scholar, Kalasalingam Institute Of Technology(Affi), Anna University,Srivilliputur. sakthisri28@gmail.com

Asst.Prof of ECE, Kalasalingam Institute Of Technology(Affi), Anna University,Srivilliputur. rajeemtech@gmail.com

Abstract — Clock gating has been heavily used in reducing the power consumption of the clock network by limiting its activity factor. Fundamentally, clock gating reduces the dynamic power dissipation by disconnecting the clock from an unused circuit block. This result in three major components of power consumption: power consumed by combinational logic whose values are changing on each clock edge; power consumed by flip-flops; power consumed by the clock tree in the design. Here clock gating approach is done for various logic circuits in response to examine its application. Index terms— Clock gating; activity factor .

asking for and discharging of the rarely used routine. The average power dissipated in an electronic routine is given as.

1. INTRODUCTION Decreasing energy intake in very extensive incorporated circuit (VLSI) style has become an interesting analysis place. Most of the convenient gadgets available in the market are battery power motivated. These gadgets encourage a limited restriction on the energy dissipation. Decreasing energy intake in such gadgets enhances battery power significantly. Due to smaller progression in battery power technology, low energy style has become a more challenging analysis place.

Paverage = Pdynamic + Pshort-circuit + Pleak +Pstatic

(1)

Paverage is the common power dissipation, Pdynamic is the dynamic power dissipation due to changing of transistors, Pshortcircuit is the short-circuit present power dissipation when there is a dc direction from power source down to the floor, Pleak is the ability dissipation due to leak voltages, P static and is the static power dissipation

Power has become a primary consideration during component style. Dynamic energy can play a role up to 50% of the total energy dissipation. Clock-gating is the most common RTL marketing for reducing dynamic energy. Effective clockgating execution requires competent application and extensive confirmation.

1) Static Power Static power is the ability dissipated by a gate when it is non-active or non-productive. Preferably, CMOS (Complementary Metal Oxide Semiconductor) circuit goes away no static (DC) power since in the stable condition; there is no immediate direction from Vdd to the floor.

There is a range of clock-gating techniques available to designers. Clearly not all of these are equivalent when it comes to reducing changing activity. Many changes are simple, while others are highly protected, trademarked methods. Most clockgating is done at the Register Transfer Level (RTL). RTL clock-gating methods can be arranged into three categories: system-level, sequential and combinational. System-level clock-gating blocks clock for an entire prevent, effectively limiting all performance. On the opposite, combinational and sequential clock-gating precisely hold clocking while the block is constantly on the produce outcome.

2) Dynamic power Dynamic power is the ability dissipated during effective condition due to changing activity of feedback indication. Since a feedback can modify without actually leading to reasoning conversion in the outcome, dynamic power can be dissipated even when an outcome doesn’t modify its reasoning condition. This part of dynamic power dissipation is caused by asking for and discharging parasitic capacitances in the routine. Dynamic power dissipation in a routine is given as:

Energy absorbed in a electronic routine is of two kinds. (1) Static power and (2) Dynamic power. Static power includes power dissipated due to leak voltages whereas dynamic power includes capacitive changing power and brief routine power. In VLSI routine time indication is used for the synchronization of effective elements. Clock power is a significant part of power mainly because time is fed to most of the routine blocks, and time changes every pattern. Thus the complete time power is a significant part of complete power dissipation in an electronic routine. Clock-gating is a well-known strategy to decrease time power. In a sequential circuit individual block utilization relies on the program, not all the blocks are used at the same time, providing an increase to dynamic power decrease chance. By clock gating strategy, time to a nonproductive section is impaired, thus preventing the power dissipation due to needless

pd=αCL fV 2dd

(2)

Where α is the charging activity , f is the function regularity, CL is the fill capacitance, Vdd is the given volts.

3) Short-Circuit Power The short-circuit power intake, P short-circuit, is due to the present circulation through the immediate direction current between the ability source and the floor during the conversion stage.

4) Leakage Power

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