Low noise and low power voltage-controlled oscillator (VCO) using transconductance (gm) degeneration
First Claim
1. A voltage controlled oscillator (VCO), comprising:
- a resonant tank circuit;
an active negative transconductance circuit connected with the resonant tank circuit, comprising;
cross-coupled transistors having drains connected with the resonant tank circuit; and
an impedance connected between sources of the cross-coupled transistors and a reference voltage; and
a bias current circuit for sourcing or sinking a bias current through the resonant tank circuit and the active negative transconductance circuit to generate an oscillating signal.
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Accused Products
Abstract
Certain aspects of the present disclosure generally relate to voltage-controlled oscillators (VCOs) using a lowered or an adjustable negative transconductance (−gm) compared to conventional VCOs. This −gm degeneration technique suppresses the noise injected into an inductor-capacitor (LC) tank of the VCO, thereby providing lower signal-to-noise ratio (SNR) for a given VCO voltage swing, lower power consumption, and decreased phase noise. One example VCO generally includes a resonant tank circuit, an active negative transconductance circuit connected with the resonant tank circuit, and a bias current circuit for sourcing or sinking a bias current through the resonant tank circuit and the active negative transconductance circuit to generate an oscillating signal. The active negative transconductance circuit includes cross-coupled transistors and an impedance connected between the cross-coupled transistors and a reference voltage.
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Citations
21 Claims
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1. A voltage controlled oscillator (VCO), comprising:
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a resonant tank circuit; an active negative transconductance circuit connected with the resonant tank circuit, comprising; cross-coupled transistors having drains connected with the resonant tank circuit; and an impedance connected between sources of the cross-coupled transistors and a reference voltage; and a bias current circuit for sourcing or sinking a bias current through the resonant tank circuit and the active negative transconductance circuit to generate an oscillating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for wireless communications, comprising:
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at least one antenna; and at least one of a receiver configured to receive, or a transmitter configured to send, a radio frequency (RF) signal via the at least one antenna, the at least one of the receiver or the transmitter having a voltage controlled oscillator (VCO) comprising; a resonant tank circuit; an active negative transconductance circuit connected with the resonant tank circuit, comprising; cross-coupled transistors having drains connected with the resonant tank circuit; and an impedance connected between sources of the cross-coupled transistors and a reference voltage; and a bias current circuit for sourcing or sinking a bias current through the resonant tank circuit and the active negative transconductance circuit to generate an oscillating signal. - View Dependent Claims (19, 20, 21)
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Specification