Low-power 4-2 compressor circuits

Abstract

The results of a comprehensive examination of 4-2 compressor circuits specifically optimized for low-power operation using CMOS double pass-transistor logic and inverter-based CMOS partial-swing and full-swing logic families are presented. The results show that double pass-transistor and inverter-based logic 4-2 compressors save 211–492% more power and are 32.2—332% more power-efficient at 5 V supply voltage and up to 151% at 3 V supply voltage than 4-2 compressors designed with conventional static CMOS logic. In addition, the inverter-based partial swing (PS) CMOS 4-2 compressor saves more power and is more power-efficient (power-delay product) than its double pass-transistor logic counterpart in the power supply range 2.8–5 V. Below 2.8 V the results show that a 4-2 compressor designed with double pass-transistor logic is more power-efficient than any other 4-2 compressor design for all loads. Low-power 4-2 compressor circuits designed with partial-swing inverter-based logic, full-swing inverter-based logic, Double Pass-Transistor Logic and standard CMOS logic consume 174 μW, 217 μW, 242 μW and 755 μW, respectively at 5 V with load capacitance 100 fF and at frequency 50 Mhz. At 2V they consume 28 μW, 34 μW, 39 μW and 121 μW, respectively. 4-2 compressor test circuits were fabricated in 0.8 μW CMOS technology.