Patent ID: 6963250

Claim:
A voltage controlled oscillator (VCO) having a VCO output signal with selectable frequency ranges comprising: M inverting circuits coupled in series forming M+1 nodes N( 1 ) to N(M+1), wherein M is an odd integer number greater than three; M voltage controlled feedforward inverting (VCFF) circuits, each VCFF(J) having a control voltage input, a signal input I(J) coupled to a corresponding node N(J), where J is a number (1 to M), and a signal output X(J), the first number (M−2K) of the signal outputs X( 1 ) to X(M−2K) are coupled to corresponding nodes N( 4 ) to N(M−2K+3); first circuitry for selectively coupling a first feedback signal selected from signals on K of first candidate nodes (N(M+1) to N(M−2K+3)), to node N( 1 ), wherein K is an integer number greater than or equal to two and less than or equal to (M−5), in response to the one or more latched select signals, thereby generating the VCO output signal; second circuitry for selectively coupling a second feedback signal from signals on K second candidate outputs X(M−1) to X(M−2K+1) to node N( 2 ) in response to the one or more latched select signals; and third circuitry for selectively coupling a third feedback signal from signals on K third candidate outputs X(M) to X(M−2K+2) to node N( 3 ) in response to the one or more latched select signals.