Quartus® Prime Pro Edition User Guide: Power Analysis and Optimization

ID 683174
Date 4/01/2024
Document Table of Contents Toggle Rate

The toggle rate of a signal is the average number of times that the signal changes value per unit of time. The units for toggle rate are transitions per second, and a transition is a change from 1 to 0, or 0 to 1.
Note: Inaccurate signal toggle rate data is the largest source of power estimation error.

Dynamic power increases linearly with the toggle rate as you charge the board trace model more frequently for logic and routing. The Quartus® Prime software models full rail-to-rail switching. For high toggle rates, especially on circuit output I/O pins, the circuit can transition before fully charging the downstream capacitance. The result is a slightly conservative prediction of power by the Power Analyzer.

Note: The transceiver I/O toggle rate is determined by the XCVR data rate value specified in your IP catalog settings. Do not include transceiver I/O toggle rate in the default toggle rates that you specify in the Power Analyzer.