Semicustom Design Methodology of Power Gated Circuits for Low Leakage Applications

The application of power gating to cell-based semi- custom design typically calls for customized cell libraries, which incurs substantial engineering efforts. In this brief, a semicustom design methodology for power gated circuits that allows unmodified conventional standard-cell elements is proposed. In particular, a new power network architecture is proposed for cell-based power gating circuits. The impact of body bias on current switch design and the layout method of current switch for flexible placement are investigated. The circuit elements that supplement cell-based power gating design are then discussed, including output interface circuits and state retention flip-flops. The proposed methodology is applied to ISCAS benchmark circuits and to a commercial Viterbi decoder with 0.18-mum CMOS technology.