Tri-mode Operation for Noise Reduction and Data Preservation in Low-Leakage Multi-Threshold CMOS Circuits

Abstract

Multi-threshold CMOS (MTCMOS) is the most widely used circuit technique for suppressing subthreshold leakage currents in idle circuits. When a conventional MTCMOS circuit transitions from SLEEP mode to ACTIVE mode, voltages of power and ground distribution networks are disturbed. Mode transition noise phenomenon in MTCMOS circuits is examined in this chapter. An MTCMOS circuit technique with three operating modes (tri-mode) is described for noise suppression during activation events. A threshold voltage tuning methodology is presented to further alleviate the mode transition noise with smaller sleep transistors in MTCMOS circuits. Alternative applications of tri-mode MTCMOS for data preservation and leakage power reduction in idle memory elements are also discussed.

A New 8T SRAM Circuit with Low Leakage and High Data Stability Idle Mode at 70nm Technology

“…Leakage current flows through the circuits during idle mode 7 . MTCMOS and power and ground gating are the most widely utilized circuit techniques for suppressing the leakage current 8,9 . In this paper a new single ended 8T SRAM is explored.…”

Mode transition timing and energy overhead analysis in noise-aware MTCMOS circuits

“…The internal nodes of low-|V th | circuit block transition to correct logic states stage by stage depending on the input vectors that are applied to the MTCMOS circuit. Energy (E R_Switching þE R_Short_Circuit ) is consumed (from T 5 to T 6 ) due to the switching and short circuit currents that are produced by the low-|V th | circuit block during a reactivation event [4][5][6][7]. The leakage energy (E R_Leakage ) consumed by the sleep signal generator and the MTCMOS circuit during the reactivation delay (T 4 to T 6 ) also contributes to the reactivation energy consumption.…”

“…Power/ground gating with a multi-threshold CMOS (MTCMOS) technology is the most widely used leakage power suppression technique in idle integrated circuits [1][2][3][4][5][6][7][8][9][10][11][12]15,16]. In an MTCMOS circuit, high threshold voltage (high-|V th |) sleep transistors (header and/or footer) are used to cut off the power supply and/or the ground connections to an idle low threshold voltage (low-|V th |) circuit block.…”

“…With CMOS technology scaling, leakage currents have become important sources of power consumption in nanoscale integrated circuits [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Power/ground gating with a multi-threshold CMOS (MTCMOS) technology is the most widely used leakage power suppression technique in idle integrated circuits [1][2][3][4][5][6][7][8][9][10][11][12]15,16].…”

“…With the increasing number of autonomous power/ground gating domains that are employed for more effective suppression of leakage currents in each new CMOS technology generation, reactivation noise (power and ground bouncing noise) that is produced by awakening MTCMOS circuit blocks has become an important reliability concern in modern integrated circuits [4][5][6][7][8].…”