SUPPLY REGULATED VOLTAGE CONTROLLED OSCILLATOR INCLUDING ACTIVE LOOP FILTER AND PHASE LOCKED LOOP USING THE SAME
First Claim
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1. A supply regulated voltage controlled oscillator including an operational amplifier used as a supply regulator and a supply controlled oscillator, the supply regulated voltage controlled oscillator comprising:
- a negative feedback circuit feeding an output signal of the operational amplifier back to an inverting input terminal of the operational amplifier,wherein the negative feedback circuit has a loop filter constituted by passive elements as to serve as an active loop filter, and whereby the supply regulated voltage controlled oscillator has an active loop filter function.
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Abstract
The inventive concept relates to a supply regulated voltage controlled oscillator having a function of an active loop filter by sharing one operational amplifier without additional use of active elements in a supply regulated voltage controlled oscillator using an operational amplifier as a supply regulator, and a phase locked loop using the same.
15 Citations
15 Claims
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1. A supply regulated voltage controlled oscillator including an operational amplifier used as a supply regulator and a supply controlled oscillator, the supply regulated voltage controlled oscillator comprising:
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a negative feedback circuit feeding an output signal of the operational amplifier back to an inverting input terminal of the operational amplifier, wherein the negative feedback circuit has a loop filter constituted by passive elements as to serve as an active loop filter, and whereby the supply regulated voltage controlled oscillator has an active loop filter function. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A phase locked loop including a phase frequency detector, a frequency divider, a charge pump, a loop filter and a supply controlled oscillator,
wherein the phase locked loop further comprises one operational amplifier, and wherein the loop filter and the supply controlled oscillator share the operational amplifier to have a function of an active loop filter and a supply regulated voltage controlled oscillator repectively.
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12. A supply regulated voltage controlled oscillator comprising:
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a supply controlled oscillator outputting a signal corresponding to a signal of a input terminal of the supply controlled oscillator; an operational amplifier wherein a signal corresponding to a feedback signal of the supply controlled oscillator is input to an inverting input terminal of the operational amplifier, a reference voltage is input to a noninverting input terminal of the operational amplifier and an output terminal of the operational amplifier is connected to the input terminal of the supply controlled oscillator; and a negative feedback circuit feeding the output signal of the operational amplifier back to the inverting input terminal of the operational amplifier, wherein the negative feedback circuit has an active loop filter function by interacting a loop filter constituted by passive elements with the operational amplifier and whereby the supply regulated voltage controlled oscillator has an active loop filter function. - View Dependent Claims (13, 14)
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15. A phase locked loop comprising:
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a supply regulated voltage controlled oscillator outputting a clock signal corresponding to an input signal; a frequency divider receiving a feedback signal of the supply regulated voltage controlled oscillator; a phase frequency detector receiving and comparing a reference frequency and an output of the frequency divider to output a pulse corresponding to a difference between the two frequencies; a charge pump controlling charge amount on the basis of a pulse corresponding the difference between the two frequencies; an operation amplifier wherein an output of the charge pump is input to an inverting input terminal of the operation amplifier, a reference voltage is input to a noninverting input terminal of the operation amplifier and an output stage of the operation amplifier is connected to an input stage of the supply regulated voltage controlled oscillator; and a negative feedback circuit feeding an output signal of the operational amplifier back to the inverting input terminal of the operational amplifier, wherein the negative feedback circuit comprises a loop filter including passive elements to interact with the operational amplifier, and whereby having an active loop filter function.
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Specification