Glitchless wide-range oscillator, and method therefor

摘要

According to an apparatus form of the invention, oscillator circuitry for operating a number of inverters in a loop (also known as a "ring") includes a number of inverters. The inverters include a series of M inverters and a series of N inverters. The M inverters have signal propagation delay of m and the N inverters have signal propagation delay of n. The circuitry also includes means for selecting whether to exclude the N inverters from operating in the loop operable for receiving a select signal on a data input. The selecting means times assertion of the select signal on an output to select the number of inverters. In order to glitchlessly change the number of inverters operating in the loop, the selecting means has a certain delay greater than delay n.