CPC H03L 7/0995 (2013.01) [H03L 7/0891 (2013.01); H03L 7/091 (2013.01)] | 30 Claims |
1. An apparatus, comprising:
a first upper voltage rail;
a first lower voltage rail; and
a voltage controlled oscillator (VCO), comprising:
at least one second upper voltage rail;
at least one second lower voltage rail;
a ring oscillator (RO) including a set of N cascaded inverters arranged in a ring, wherein the set of N cascaded inverters are coupled between the at least one second upper voltage rail and the at least one second lower voltage rail, wherein N is a positive integer number;
at least one first frequency band select circuit coupled between the first upper voltage rail and the at least one second upper voltage rail, respectively;
at least one second frequency band select circuit coupled between the at least one second lower voltage rail and the first lower voltage rail, respectively;
at least one first VCO frequency control circuit coupled between the first upper voltage rail and the at least one second upper voltage rail, respectively; and
at least one second VCO frequency control circuit coupled between the at least one second lower voltage rail and the first lower voltage rail, respectively.
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