Replica Cascode Bias Voltage-Controlled Oscillators
First Claim
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1. A voltage oscillator comprising:
- a voltage-to-current converter configured to generate a control current responsive to receiving a control voltage, the voltage-to-current converter comprising a first transistor and a second transistor, a drain of the first transistor coupled to a source of the second transistor and a gate of the second transistor biased by a bias voltage;
a current controlled oscillator coupled to the voltage-to-current converter to receive the control current and to generate a periodic output signal having a frequency corresponding to the control current; and
a bias voltage generation circuit coupled to the voltage-to-current converter, the bias voltage generation circuit comprising a replica bias circuit configured to generate a replica voltage corresponding to a voltage at the source of the second transistor.
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Abstract
Embodiments relate to a voltage oscillator (VCO) that uses a replica bias circuit to generate a cascode bias voltage. The VCO generate an output periodic signal having a frequency and phase that is less or not susceptible to voltage swings by using a bias voltage generated in a replica bias circuit that replicates a voltage-to-current converter in the VOC. The bias voltage is generated and regulated according to a power supply voltage that supplies power to the VCO to account for voltage variations in the power supply voltage.
33 Citations
20 Claims
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1. A voltage oscillator comprising:
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a voltage-to-current converter configured to generate a control current responsive to receiving a control voltage, the voltage-to-current converter comprising a first transistor and a second transistor, a drain of the first transistor coupled to a source of the second transistor and a gate of the second transistor biased by a bias voltage; a current controlled oscillator coupled to the voltage-to-current converter to receive the control current and to generate a periodic output signal having a frequency corresponding to the control current; and a bias voltage generation circuit coupled to the voltage-to-current converter, the bias voltage generation circuit comprising a replica bias circuit configured to generate a replica voltage corresponding to a voltage at the source of the second transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of generating a periodic signal, comprising:
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generating, by a voltage-to-current converter, a control current responsive to receiving a control voltage; providing the generated control current to a current controlled oscillator to generate the periodic signal; generating, by a bias voltage generation circuit, a replica voltage corresponding to a voltage between a first transistor of the voltage-to-current converter and a second transistor of the voltage-to-current converter in a cascode configuration responsive to receiving the control voltage at a gate of the first transistor; generating, by the bias voltage generation circuit, a bias voltage by amplifying a difference between the replica voltage and a reference voltage; and applying the generated bias voltage to a gate of the second transistor of the voltage-to-current converter and a gate of a third transistor in the bias voltage generation circuit corresponding to the second transistor of the voltage-to-current converter. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A non-transitory computer readable storage medium storing digital representation of a voltage oscillator, the voltage oscillator comprising:
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a voltage-to-current converter configured to generate a control current responsive to receiving a control voltage, the voltage-to-current converter comprising a first transistor and a second transistor, a drain of the first transistor coupled to a source of the second transistor and a gate of the second transistor biased by a bias voltage; a current controlled oscillator coupled to the voltage-to-current converter to receive the control current and to generate a periodic output signal having a frequency corresponding to the control current; and a bias voltage generation circuit coupled to the voltage-to-current converter, the bias voltage generation circuit comprising a replica bias circuit configured to generate a replica voltage corresponding to a voltage at the source of the second transistor. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification