Path-based UPF Strategies Optimally Manage Power on your Designs

UPF 3.0 and 3.1 LRM combinedly introduces path-based semantics for isolation, level-shifter, and repeater strategies in conjunction with -sink and -diff_supply_only TRUE commands. This feature explicitly defines path from source to sink domain for which any of the above strategies applies. Before path-based semantics were introduced – isolation, level-shifter and repeater strategies utilized adhoc methodology – for example port splitting which makes power management very difficult. Because when isolation strategy specified on ports and it has multiple fanout going to multiple receiving logic supplies, then port-based semantics will place isolation cell on all paths. However, path-based semantics will place isolation cell in paths that goes to specified sinks or receiving logic in the strategy. This paved ways to optimally manage power on any designs. Evidently, path-based methodology adoption is not straight forward. It depends on contents of strategies, for example for isolation strategies, -location fanout, self, parent poses extra complexity to imply strategy according to expectation. This paper addresses the complexity of adoption path-based strategies through numerous examples and real designs, so that UPF user can smoothly transit from port-based adhoc to path-based standard methodology, and understand how isolation, level-shifter and repeater strategies and cells are inferred between source and sink power domain

Progyna Khondkar, Siemens EDA