DIVIDE-BY-TWO INJECTION-LOCKED RING OSCILLATOR CIRCUIT
First Claim
1. A frequency divider comprising:
- a first Injection-locked Ring Oscillator (ILRO) comprising;
a first cross-coupled transistor pair including a first N-channel transistor and a second N-channel transistor, wherein a drain of the first N-channel transistor is a first output node, wherein a drain of the second N-channel transistor is a second output node, wherein a gate of the first N-channel transistor is coupled to the second output node, and wherein a gate of the second N-channel transistor is coupled to the first output node;
a first capacitor having a first lead coupled to a source of the first N-channel transistor and a second lead coupled to a source of the second N-channel transistor; and
a first current injection circuit having a first lead coupled to the source of the first N-channel transistor, a second lead coupled to the source of the second N-channel transistor, and a first input node.
1 Assignment
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Accused Products
Abstract
A frequency divider involves a plurality of Injection-locked Ring Oscillators (ILRO). A first ILRO includes a pair of cross-coupled N-channel transistors, a pair of load resistors, an integrating capacitor, and a current injection circuit. The drain of each transistor is coupled to the gate of the other transistor. Each load resistor couples the drain of each transistor to a circuit voltage source. The integrating capacitor couples the sources of each transistor. The current injection circuit alternately opens and closes a path from the source of each transistor to circuit ground in response to an oscillatory input signal of a first frequency. In response, the voltage state at the drain of each transistor is alternately latched and toggled, generating a differential pair of oscillating signals frequency divided by two. A first and second ILRO driven in antiphase generate two differential output signals in phase quadrature.
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Citations
23 Claims
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1. A frequency divider comprising:
a first Injection-locked Ring Oscillator (ILRO) comprising; a first cross-coupled transistor pair including a first N-channel transistor and a second N-channel transistor, wherein a drain of the first N-channel transistor is a first output node, wherein a drain of the second N-channel transistor is a second output node, wherein a gate of the first N-channel transistor is coupled to the second output node, and wherein a gate of the second N-channel transistor is coupled to the first output node; a first capacitor having a first lead coupled to a source of the first N-channel transistor and a second lead coupled to a source of the second N-channel transistor; and a first current injection circuit having a first lead coupled to the source of the first N-channel transistor, a second lead coupled to the source of the second N-channel transistor, and a first input node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A frequency divider comprising:
a first Injection-locked Ring Oscillator (ILRO) having a first input lead that receives a first oscillatory signal of a first frequency, a first output lead and a second output lead that output an in-phase (I) differential output signal of a second frequency, wherein the first frequency is twice the second frequency, and wherein the ILRO comprises; a cross-coupled transistor pair including a first N-channel transistor and a second N-channel transistor, wherein a drain of the first N-channel transistor is coupled to the first output lead, wherein a drain of the second N-channel transistor is coupled to the second output lead; a capacitor having a first lead coupled to a source of the first N-channel transistor and a second lead coupled to a source of the second N-channel transistor; and a current injection circuit having a first lead coupled to the source of the first N-channel transistor, a second lead coupled to the source of the second N-channel transistor, and a third lead coupled to the first input lead of the first ILRO. - View Dependent Claims (12)
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13. A method comprising:
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latching a voltage present on a first output node of a first Injection-locked Ring Oscillator (ILRO) to a first voltage state in response to a digital high state of a first input signal, wherein a current substantially equal to a circuit supply voltage divided by a first load resistor value flows through a first N-channel transistor of the first ILRO; and toggling the voltage present on the first output node to a second voltage state in response to a digital low state of the first input signal, wherein the voltage present on the first output node is increased by integrating charge across a first capacitor. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A frequency divider circuit comprising:
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a conductor that receives a first input signal onto the frequency divider circuit; and means for frequency dividing the input signal by a fixed integer thereby generating an in-phase (I) differential output signal, wherein the means includes a first capacitor, and wherein the first capacitor at least in part increases a voltage swing of the I differential output signal. - View Dependent Claims (22, 23)
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Specification