VCO resonance tuning
AssigneeSkyworks Solutions, Inc.
InventorJackie K. Cheng
Life of this patent
Estimating the term…
Abstract
Techniques are provided for compensating for variations in capacitance of capacitors used in resonant circuits, particularly varactors used in voltage-controlled oscillators. Indications of actual varactor capacitances are used to determine which of several inductances to use in the resonant circuit with the varactor. The inductances may be composed of a bondwire inductance, and may also be composed of one or more coil inductors. Based on the determined capacitance indication, a bondwire is connected from a common bondpad to a selected bondpad to complete the resonant tank circuit such that an LC product of the tank circuit is within a desired or acceptable LC product range.
Claims26
A voltage-controlled oscillator (VCO) comprising:
- an input configured to receive a tuning voltage;
- a capacitive element coupled to the input and having an actual capacitance C;
- a first connection point;
- a plurality of second connection points for coupling to the first connection point, at least one of the plurality of connection points being coupled to the first connection point by a bondwire of a length selected to provide a compensating inductance, at least the compensating inductance and the capacitive element being coupled to form a tank, the compensating inductance compensating for a deviation in the actual capacitance C from a desired capacitance of the capacitive element and affecting a total inductance L, that includes at least the compensating inductance, such that an LC product of the inductance L and the capacitance C is within a desired range of LC product values;
- and
- an output coupled to the tank and configured to carry an output signal having a frequency associated with the LC product.
A voltage-controlled oscillator (VCO) comprising:
- an input configured to receive a tuning voltage;
- an LC-tank including:
- a varactor coupled to the input to receive the tuning voltage and having a capacitance C when the tuning voltage is at a nominal level;
- a primary inductor;
- and
- inductance means for coupling different compensating inductances to the primary inductor, at least one of the different compensating inductances being coupled to the primary inductor to provide at least a portion of a total inductance L of the LC-tank, the primary inductor and the at least one compensating inductance being coupled to the varactor, the LC-tank having an oscillation center frequency within a desired range when the tuning voltage is at the nominal level;
- and
- an output coupled to the LC-tank and configured to carry an output signal having a frequency associated with the LC product;
- wherein the inductance means includes a common bondpad, a plurality of selectable bondpads, and at least one bondwire connecting the common bondpad to at least one of the selectable bondpads.
A method of producing a circuit including a voltage-controlled oscillator (VCO), the method comprising:
- providing VCO components including an input for receiving a tuning voltage, a varactor for receiving the tuning voltage, and an output for conveying an oscillating signal whose frequency is at least partially dependent upon a capacitance of the varactor;
- completing at least one of a plurality of possible connections to the varactor to couple an inductance to the varactor to at least partially compensate for a difference between a desired capacitance and an actual capacitance of the varactor, which of the possible connections is completed being dependent upon knowledge of the difference between the desired and actual capacitances of the varactor.
A method of making a chip including a voltage-controlled oscillator (VCO), the method comprising:
- forming a wafer including VCO components including an input for receiving a tuning voltage, a common connection pad coupled to the input, a varactor for receiving the tuning voltage, multiple selectable connection pads coupled to the varactor, and an output for conveying an oscillating signal whose frequency is at least partially dependent upon a capacitance of the varactor;
- determining a difference between an actual capacitance associated with the varactor and a designed capacitance of the varactor;
- selecting one of the multiple selectable connection pads based on the determined difference;
- and
- wire bonding the common connection pad to the selected one of the multiple selectable connection pads.
Dependencies are inferred from the claim text.