NLPM Power and Leakage Characterization

006_cell : NLPM Power and Leakage Characterization

Minimum Required Versions: AccuCell 2.6.0.R, SmartSpice 4.6.2.R

This example explains the use of AccuCell's power and leakage characterization options for creating Non-Linear-Power-Model (NLPM) power models for a simple inverter and a basic D flip-flop cells using the embedded SmartSpice SPICE engine to perform characterization.

NLPM table models are generated at the SAME time during the SAME characterization simulations as the timing models using the SAME table indexes and therefore negligible overhead is incurred when both model types are enabled. Both dynamic and static (leakage) power can be characterized and modeled under a number of options. Static power can be modeled as either a single value (avg) for all input state conditions or as a full state specific set of leakage values. Static power is characterized by DC analysis under all state conditions independently of the choice of reporting format. State dependent static power can be modeled by specifying STATE_LEAKAGE_PWR 1 in the Cell_EX6.cfgfile. Dynamic power associated with both hidden input switch events and switching outputs can be characterized and modeled with several reporting options such as CHAR_POWER_METHOD, INCLUDE_SWITCHING_PWR, INCLUDE_LEAKAGE_PWR.

CHAR_POWER_METHOD specifies if power characterization is to be done based on AVERAGE, PEAK or RMS power measurement.

INCLUDE_SWITCHING_PWR specifies the power model table format to generate regarding the inclusion of rising or falling edge load switching power. Different tools with different configuration setting can require different library power modeling. Although most tools can accept most or all the format variations by modifying their configuration files. Each format has its own advantages. AccuCell supports all options.

INCLUDE_LEAKAGE_PWR specifies the power model table format to generate regarding the inclusion of leakage power. In some processes the leakage power can be significant. As a result it is sometimes desirable to not include it in the switching power tables and instead address its effects by separately controled means to yield higher accuracy power analysis results.