Variable capacitor structure
AssigneeInternational Business Machines Corporation
InventorRam Kelkar
Life of this patent
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Abstract
Variable capacitor structures and methods of use are disclosed. The variable capacitor structures include a variable controlled oscillator which includes a variable capacitor structure having at least one capacitor set driven by a control gate voltage of a voltage control circuit which comprises a logic cell that senses a selected frequency band and sets the control gate voltage based on the selected frequency band.
Claims20
A variable controlled oscillator comprising a variable capacitor structure having at least one capacitor set driven by a control gate voltage of a voltage control circuit which comprises a logic cell that senses a selected frequency band and sets the control gate voltage based on the selected frequency band,
- wherein the logic cell is structured to select certain diode connected field effect transistors (FETs) to be coupled to one of a ground and a voltage node, in order to affect the control gate voltage and, hence change frequency in certain bands.
A variable controlled oscillator comprising a variable capacitor structure having at least one capacitor set driven by a control gate voltage of a voltage control circuit which comprises a logic cell that senses a selected frequency band and sets the control gate voltage based on the selected frequency band,
- wherein the variable capacitor structure comprises coarse tune capacitors and fine tune capacitors,
- wherein the coarse tune capacitors comprise four sets of capacitors controlled by respective control bits <3:0>and the fine tune capacitors are controlled by voltages obtained from a filter.
A variable controlled oscillator comprising a variable capacitor structure having at least one capacitor set driven by a control gate voltage of a voltage control circuit which comprises a logic cell that senses a selected frequency band and sets the control gate voltage based on the selected frequency band, wherein:
- the control gate voltage is held at ground (gnd) for frequency bands 0-8 so that capacitance of the at least one capacitor set is at a lowest capacitance;
- and
- the control gate voltage is held at a predetermined voltage above ground for frequency bands 9-15 based on the selected frequency band, thereby increasing the capacitance of the at least one capacitor set.
A variable capacitor structure, comprising:
- a first variable capacitor configuration having a binary weighted array of capacitor segments, each of the capacitor segments being enabled by one of a plurality of binary control bits;
- a second variable capacitor configuration having a capacitance controlled by a first analog control voltage provided by a phase-locked loop;
- and
- a third variable capacitor configuration having a capacitance controlled by a control voltage set by a logic cell that senses a selected frequency band,
- wherein the logic cell is structured to select certain diode connected field effect transistors (FETs) to be coupled to one of a ground and a voltage node, in order to affect the control voltage and, hence change frequency in certain bands.
A method for equalizing gain of a voltage controlled oscillator over a plurality of frequency bands, comprising:
- determining a frequency band;
- selecting a control voltage based on the determined frequency band;
- and
- setting the control voltage to a variable capacitor by a logic cell,
- wherein the logic cell is structured to select certain diode connected field effect transistors (FETs) to be coupled to one of a ground and a voltage node, in order to affect the control voltage and, hence change frequency in certain bands.
Dependencies are inferred from the claim text.