Frequency-fine tuning circuit for voltage-controlled oscillator, has varactors coupled with one another ate node, and center bias voltage unit to maintain node voltage at constant bias voltage level

摘要

The circuit has a varactor (Cv21) coupled with another varactor (Cv22) at a node. A center bias voltage unit (110) maintains a node voltage of the node at a constant bias voltage level, where the varactors have accumulation metal oxide semiconductor (AMOS). A pair of blocking capacitors (C21, C22) having metal insulator metal (MIM) capacitors is countersunk between output terminals and the varactors, respectively. A tuning voltage input terminal is electrically coupled with the node for applying tuning voltage. Independent claims are also included for the following: (1) a frequency-coarse tuning circuit for a voltage-controlled oscillator, including two varactors (2) a voltage-controlled oscillator including a frequency-fine tuning circuit.