Patent ID: 6515550
Filing Date: 2003-02-04
Classification: H03B,H03L

Abstract:
A ring oscillator comprising:a series of a plurality of inverting stages connected in a loop; said plurality of inverting stages including a first multiplexer stage; said first multiplexer stage including a first signal input and a second signal input and a select input; an oscillator feedback signal applied to said first signal input of said first multiplexer stage; a startup circuit coupled to said first multiplexer stage; said startup circuit including a startup circuit signal coupled to said second signal input of said first multiplexer stage for starting the ring oscillator; said startup circuit including a multiplexer select signal coupled to said select input of said first multiplexer stage for controlling said first multiplexer stage to select said oscillator feedback signal or said startup circuit signal; and said startup circuit including a run signal; said multiplexer select signal being responsive to said run signal for controlling said first multiplexer stage, and said startup circuit signal coupled to said second signal input of said first multiplexer stage being responsive to said run signal for starting the ring oscillator.