Patent ID: 7710208
Filing Date: 2010-05-04
Classification: H03K

Abstract:
1. A multi-speed ring oscillator comprising: a control circuit for receiving a frequency-selection signal operative to select from at least two different ring oscillator frequencies of an oscillating signal, said control circuit using said frequency-selection signal to generate a first control signal and a second control signal; a primary chain of an odd number of serially connected NOT gates, said primary chain including a primary switching NOT gate being responsive to the first control signal and operative to perform a logical NOT function or an IGNORE function on a first oscillating input signal to generate a first output signal; and a secondary chain of serially connected NOT gates, said secondary chain being logically parallel to at least said primary switching NOT gate of said primary chain, said secondary chain including a secondary switching NOT gate being responsive to the second control signal and operative to perform a logical NOT function or an IGNORE function on a second oscillating input signal to generate a second output signal; and wherein responsive to said first control signal, said oscillating signal has a first frequency that depends on a first number of NOT gates; and responsive to said second control signal, said oscillating signal has a second frequency that depends on a second number of NOT gates, said second number of NOT gates being different than said first number of NOT gates.