In the previous work, the problem of nding gate delays to eliminate glitches has been solved by linear programs (LP) requiring an exponentially large number of constraints. By introducing two additional variables per gate, namely, the fastest and the slowest arrival times, besides the gate delay,we reduce the number of the LP constraints to be linear in circuit size. For example, the 469-gate c880 circuit requires 3,611 constraints as compared to the 6.95 million constraints needed with the previous method. The reduced constraints provably produce the same exact LP solution as obtained by the exponential set of constraints. For the rst time, we are able to optimize all ISCAS'85 benchmarks. For the c7552 circuit, when the input to output delay is constrained not to increase, a design with 366 delay bu ers consumes only 34 % peak and 38 % average power as compared to an unoptimized design. As shown in previous work, the use of delay bu ers is essential in this case. The practicality of the design is demonstrated by implementing an optimized 4-bit ALU circuit for which the power consumption was obtained by a circuit-level simulator. 1.

Abstract. The time taken for a CMOS logic gate output to change after one or more inputs have changed is called the output delay of the gate. A conventional multi-input CMOS gate is designed to have the same input to output delay irrespective of which input caused the output to change. A gate which can offer different delays for different input-output paths through it, is known as a v ¯ ariable input delay(VID) gate and the maximum difference in delay between any two paths through the same gate is known as “ub”. These gates can be used for minimizing the active power of a digital CMOS circuit using a previosuly described technique called v ¯ ariable input delay(VID) logic. This previous publication proposed three different designs for implementating the VID gate. In this paper, we describe a technique for transistor sizing of these three flavors of the VID gate for a given delay requirement. We also describe techniques for calculating the ub of each flavor. We outline an algorithm for quick determination of the transistor sizes for a gate for a given load capacitance. 1

The power dissipated in a CMOS circuit consists of dynamic power, leakage power and short-circuit power components. The topic of this paper is the reduction of dynamic power. When an input vector is applied to the primary inputs (PI), the minimum power requirement for each gate output is to produce

There are many ways of combining the transistors to perform the logic functions such as NOT, NAND and NOR. We will describe the CMOS design style which is the most prominent in current day technologies.