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US 2008/0164955 A1Published application
Voltage controlled oscillator circuits and methods using variable capacitance degeneration for increased tuning range
OwnerUllrich R. Pfeiffer, Brian Welchinventors
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Abstract
Voltage controlled oscillator circuits are provided in which variable capacitance degeneration is employed to provide increased tuning ranges and output amplitudes for VCO circuits for millimeter wave applications
Claims21
A VCO (voltage controlled oscillator) circuit, comprising:
- a resonant circuit having a resonant frequency that is controlled by a first control voltage to set an oscillation frequency of the VCO;
- and
- an oscillator core coupled to the resonant circuit to provide a negative impedance that compensates losses of the resonant circuit and sustains oscillation of the VCO,
- wherein the oscillator core implements variable capacitive degeneration to adjust an amount of negative impedance provided by the oscillator core based on a second control voltage.
1 more element
A VCO (voltage controlled oscillator) circuit, comprising:
- a LC resonant circuit having a fixed-value inductance and a tunable capacitance that is controlled by a first control voltage to set an oscillation frequency of the VCO;
- and
- an oscillator core comprising a cross-coupled pair of bipolar junction transistors and an emitter degeneration circuit which provides variable capacitive degeneration under control of a second control voltage.
A method for operating a VCO (voltage controlled oscillator), comprising:
- applying a first control voltage to a first control port of the VCO to set an oscillation frequency of the VCO;
- and
- applying a second control voltage to a second control port of the VCO to control variable capacitive degeneration of a VCO core and tune a negative impedance provided by the VCO core.
Dependencies are inferred from the claim text.