Digitally controlled oscillator with segmented varactor bank and multiple-voltage linearization, and associated apparatus

A digitally controlled oscillator (DCO) with segmented varactor bank and multiple-voltage linearization, the DCO comprising:

• a varactor array, the varactor array comprising a plurality of varactors positioned in the segmented varactor bank, wherein the varactor array is composed of multiple varactor sets, any varactor set among the multiple varactor sets is composed of at least one varactor unit among multiple varactor units belonging to the multiple varactor sets, and any varactor unit among the multiple varactor units is composed of a pair of varactors among the plurality of varactors;
• a plurality of bridge biasing resistors, positioned in the segmented varactor bank, configured to bridge the multiple varactor sets of the varactor array, for biasing the multiple varactor sets with a series of intermediate voltages within a predetermined biasing voltage range controlled by a predetermined biasing voltage;
• a plurality of capacitors, coupled between the multiple varactor sets within the segmented varactor bank and a set of differential oscillation nodes of the DCO, configured as alternating current (AC) coupled capacitors between the multiple varactor sets and the set of differential oscillation nodes, wherein the any varactor set among the multiple varactor sets is coupled to the set of differential oscillation nodes via a set of AC coupled capacitors, respectively;
• and
• a negative transconductance (gm) network (−gm network), coupled to the set of differential oscillation nodes, configured to sustain oscillation of a set of differential oscillation signals at the set of differential oscillation nodes;
• wherein one set of varactor units and multiple remaining sets of varactor units among the multiple varactor units, the one set of varactor units and the multiple remaining sets of varactor units respectively belonging to at least one varactor set and remaining varactor sets among the multiple varactor sets, are configured as active units and frozen units to receive a set of tune voltages and a set of predetermined voltages, respectively, for providing the multiple-voltage linearization at the active units.