Fine tuning control for a digitally controlled oscillator

摘要

Methods, apparatuses, and systems for providing a variable capacitance using an array of capacitor cells are discussed. In the fine tuning bank of an inductor/capacitor (LC)-tank of a digitally controlled oscillator (DCO), control is implemented by selecting a boundary cell from the array of capacitor cells and having every cell before the boundary cell in a circuit path be grounded and having the boundary cell and every cell after the boundary cell in the circuit path be connected to a voltage source. The circuit path may be the one formed by using thermometer coding in the fine tuning bank.

主权项

1. An array of capacitor cells that produce a variable capacitance, comprising:
n row control lines; n column control lines; and an n×n array of capacitor cells which varies its overall capacitance by thermometer coding forming a path through the n×n array, each capacitor cell comprising:
a feeder input for at least one of output of a previous cell in the path or output from a feeder line;a column control line input;a row control line input; andan output for the feeder input of a next cell in the path, wherein each cell in the array is in one of two states; wherein a boundary cell is selected by asserting its row control line input among the n row control lines and asserting its column control line input among the n column control lines, wherein all cells before the boundary cell in the path output a value of the feeder line connected to the feeder input of a first cell in the path, wherein the first cell is in a first column and a first row of the array of capacitor cells, wherein the boundary cell and all cells after the boundary cell in the path output a value opposite to the value of the feeder line connected to the first cell in the path, and wherein each cell before the boundary cell in the path is in a first state of the two states, and the boundary cell and each cell after the boundary cell is in a second state of the two states.