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US 6,650,188 B1Granted
Coupling for LC-based VCO
AssigneeLattice Semiconductor Corporation
InventorsEdwin Chan, Ming Qu, Ji Zhao
Life of this patent
Estimating the term…
Abstract
A two-stage coupling loop system that provides in-phase and quadrature signals in the two stages. Each stage includes a signal coupler, an LC-based voltage controlled oscillator (VCO) and an in-loop signal buffer that provides an additional controllable phase shift. Inclusion of the buffers in the loop decreases the capacitance load of each VCO.
Claims14
An LC-based ring oscillator comprising:
- a first LC stage comprising a coupler, an LC-based voltage controlled oscillator (VCO), and a buffer each having at least one input terminal and at least one output terminal, the output terminal of the coupler being connected to the input terminal of the VCO and the output terminal of the VCO being connected to the input terminal of the buffer;
- and
- a second LC stage having an input terminal and an output terminal,
- wherein the output terminal of the buffer of the first LC stage is connected to the input terminal of the second LC stage and the output terminal of the second LC stage is connected to the input terminal of the coupler of the first LC stage.
1 more element
An LC-based ring oscillator comprising:
- a first LC stage including a coupler, an LC-based voltage controlled oscillator (VCO), and a buffer each having at least two input terminals and at least two output terminals, the output terminals of the coupler being connected to the following input terminals of the VCO and the output terminals of the VCO being connected to the following input terminals of the buffer;
- and
- a second LC stage having at least two input terminals and at least two output terminals;
- wherein the output terminals of the buffer of the first LC stage are connected to the following input terminals of the second LC stage and the output terminals of the second LC stage are connected to the following input terminals of the coupler of the first LC stage;
- and
- wherein the output terminals of at least one of the second LC stage and the coupler, VCO, and buffer of the first LC stage is connected with reversed polarity to the following input terminals.
3 more elements
An LC-based ring oscillator comprising:
- a first LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the first stage having at least two input terminals;
- and
- a second LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the second stage having at least two input terminals;
- wherein the output terminals of the buffer of the first LC stage are connected to the input terminals of the second LC stage and the output terminals of the buffer of the second LC stage are connected to the input terminals of the first LC stage;
- and
- wherein the output terminals of the buffer of the first LC stage are connected with reversed polarity to the input terminals of the second LC stage.
3 more elements
An LC-based ring oscillator comprising:
- a first LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the first stage having at least two input terminals;
- and
- a second LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the second stage having at least two input terminals;
- wherein the output terminals of the buffer of the first LC stage are connected to the input terminals of the second LC stage and the output terminals of the buffer of the second LC stage are connected to the input terminals of the first LC stage;
- and
- wherein the output terminals of the VCO of the first LC stage are connected with reversed polarity to the input terminals of the buffer of the first LC stage.
3 more elements
An LC-based ring oscillator comprising:
- a first LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the first stage having at least two input terminals;
- and
- a second LC stage including at least an LC-based voltage controlled oscillator (VCO) and a buffer operable to provide a phase shift, each of the VCO and buffer having at least two input terminals and at least two output terminals, the output terminals of the VCO being connected to the input terminals of the buffer, the second stage having at least two input terminals;
- wherein the output terminals of the buffer of the first LC stage are connected to the input terminals of the second LC stage and the output terminals of the buffer of the second LC stage are connected to the input terminals of the first LC stage;
- and
- wherein the first LC stage includes a coupler having at least two input terminals and two output terminals, the output terminals of the coupler being connected to the input terminals of the VCO, the input terminals of the coupler being the input terminals of the stage.
3 more elements
Dependencies are inferred from the claim text.