Fully integrated differential LC PLL with switched capacitor loop filter
First Claim
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1. A circuit comprising:
- a loop filter, wherein the filter comprises an active integrator configured to generate one or more tuning signals; and
a voltage-controlled oscillator (VCO) coupled to the loop filter and configured to generate a feedback signal based on the one or more tuning signals,wherein generating the one or more tuning signals is based on the feedback signal,wherein the loop filter is implemented on an integrated chip, andwherein the loop filter does not comprise a capacitor that is external to the integrated chip and used to generate the tuning signals.
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Abstract
A circuit comprising a loop filter, wherein the filter comprises an active integrator configured to generate one or more tuning signals, and a voltage-controlled oscillator (VCO) coupled to the loop filter and configured to generate a feedback signal based on the one or more tuning signals, wherein generating the one or more tuning signals is based on the feedback signal.
55 Citations
20 Claims
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1. A circuit comprising:
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a loop filter, wherein the filter comprises an active integrator configured to generate one or more tuning signals; and a voltage-controlled oscillator (VCO) coupled to the loop filter and configured to generate a feedback signal based on the one or more tuning signals, wherein generating the one or more tuning signals is based on the feedback signal, wherein the loop filter is implemented on an integrated chip, and wherein the loop filter does not comprise a capacitor that is external to the integrated chip and used to generate the tuning signals.
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2. A circuit comprising:
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a loop filter, wherein the filter comprises an active integrator configured to generate one or more tuning signals; and a voltage-controlled oscillator (VCO) coupled to the loop filter and configured to generate a feedback signal based on the one or more tuning signals, wherein generating the one or more tuning signals is based on the feedback signal, wherein the active integrator is a differential integrator comprising a differential pair of operational amplifiers (OAs), and wherein the differential pair of OAs are both configured to receive the feedback signal.
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3. A circuit comprising:
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a loop filter, wherein the filter comprises an active integrator configured to generate one or more tuning signals; and a voltage-controlled oscillator (VCO) coupled to the loop filter and configured to generate a feedback signal based on the one or more tuning signals, wherein generating the one or more tuning signals is based on the feedback signal, and wherein the active integrator comprises one or more operational amplifiers (OAs) each configured to receive the feedback signal. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method implemented by a voltage-controlled oscillator (VCO) comprising:
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receiving a tuning voltage; and generating an oscillating signal whose frequency is based on the tuning voltage, wherein a relationship between the tuning voltage and the frequency of the oscillating signal is characterizable via frequency versus voltage curves, and wherein spacings between frequency versus voltage curves of the VCO are linear and a slope of the frequency versus voltage curves is substantially constant. - View Dependent Claims (14, 15)
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16. A phase lock loop (PLL) comprising:
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an active low pass filter configured to generate one or more tuning signals; and a voltage-controlled oscillator (VCO) coupled to the active low pass filter and configured to; generate a feedback signal based on the one or more tuning signals; and feed the feedback signal to the active low pass filter. - View Dependent Claims (17, 18, 19, 20)
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Specification