Spread spectrum clock generation using a tapped delay line and entropy injection

摘要

Spread spectrum clocking circuitry may be configured to produce a spread spectrum clock signal that coordinates the actions of functional circuitry. Spread spectrum clocking circuitry may be configured to include delay circuitry configured to generate a random delay signal based on a random input value and generate the spread spectrum clock signal based on the random delay signal. By introducing true randomness into the delay signal, spread spectrum clocking signal may be able to generate a truly random, as opposed to a merely pseudo random, clock signal.

主权项

1. A device comprising:
a clock signal generator configured to generate a clock signal; a delay line comprising one or more delay elements, wherein the one or more delay elements are configured to add delay to the clock signal; a multiplexer configured to output a random delay signal, wherein an amount of delay of the random delay signal corresponds to a number of the one or more delay elements selected by the multiplexer and wherein the number of the one or more delay elements selected by the multiplexer is based on a random input value; and spread spectrum clocking circuitry configured to generate a spread spectrum clock signal based on the random delay signal.