High frequency divider circuits and methods
First Claim
1. A divider circuit comprising:
- a differential circuit having first and second inputs to receive a first differential signal and first and second differential output nodes, wherein the differential circuit has a first bias current generated by a first bias generator; and
a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node, and wherein the cross-coupled circuit has a second bias current generated by a second bias generator that is independent of the first bias current,wherein the differential circuit is coupled to a first transistor having a control terminal to receive a signal to be divided, and wherein the first bias generator is coupled to the differential circuit through the first transistor, andwherein the cross-coupled circuit is coupled to a second transistor having a control terminal to receive the complement of the signal to be divided, and wherein the second bias generator is coupled to the cross-coupled circuit through the second transistor.
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Abstract
Embodiments of the present invention include circuits and methods for dividing high frequency signals. In one embodiment the present invention includes a divider circuit comprising a differential circuit having first and second inputs to receive a first differential signal, a first frequency control input and first and second differential outputs, wherein the differential circuit has a first bias current. The divider circuit further includes a cross-coupled circuit having outputs coupled to the differential circuit outputs and a second frequency control input, wherein the cross-coupled circuit has a second bias current. Embodiments of the present invention may include circuits for controlling the relationship between bias currents and circuit parameters that vary with process or temperature or both.
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Citations
30 Claims
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1. A divider circuit comprising:
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a differential circuit having first and second inputs to receive a first differential signal and first and second differential output nodes, wherein the differential circuit has a first bias current generated by a first bias generator; and a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node, and wherein the cross-coupled circuit has a second bias current generated by a second bias generator that is independent of the first bias current, wherein the differential circuit is coupled to a first transistor having a control terminal to receive a signal to be divided, and wherein the first bias generator is coupled to the differential circuit through the first transistor, and wherein the cross-coupled circuit is coupled to a second transistor having a control terminal to receive the complement of the signal to be divided, and wherein the second bias generator is coupled to the cross-coupled circuit through the second transistor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A divider circuit comprising:
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a differential circuit having first and second inputs to receive a first differential signal, and first and second differential output nodes, wherein the differential circuit is coupled to a first bias current generator; and a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node, wherein the cross-coupled circuit is coupled to a second bias current generator, wherein the differential circuit is coupled to a first transistor having a control terminal for receiving a signal to be divided, and wherein the first bias current generator is coupled to the differential circuit through the first transistor, and wherein the cross-coupled circuit is coupled to a second transistor having a control terminal for receiving the complement of the signal to be divided, and wherein the second bias current generator is coupled to the differential circuit through the second transistor. - View Dependent Claims (8, 9, 10, 11)
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12. A divider circuit comprising:
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first and second transistors having sources coupled together to form a differential circuit, the first transistor having a first output terminal and the second transistor having a second output terminal; first and second cross-coupled transistors having sources coupled together, the first cross-coupled transistor having a first output terminal coupled to the first output terminal of the first transistor and the second cross-coupled transistor having a second output terminal coupled to the second output terminal of the second transistor; a first resistor coupled between the first output terminal of the first transistor and a supply terminal, the first resistor having a first resistance value; a second resistor coupled between the second output terminal of the second transistor and the supply terminal, the second resistor having a second resistance value approximately equal to the first resistance value; a third transistor having a control terminal coupled to a signal to be divided and a first terminal coupled to the sources of the first and second transistors, wherein the third transistor is coupled to a first bias generator that generates first bias current in the first and second transistors; and a fourth transistor having an control terminal coupled to a complement of the signal to be divided and a first terminal coupled to the sources of the cross-coupled transistors, wherein the fourth transistor is coupled to a second bias generator that generates second bias current in the first and second cross-coupled transistors. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A divider circuit comprising:
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a differential circuit having first and second inputs to receive a first differential signal and first and second differential output nodes; a cross-coupled circuit having a first control terminal coupled to a second output of the cross-coupled circuit and the first differential output node and a second control terminal coupled to a first output of the cross coupled circuit and the second differential output node; a first transistor coupled to the differential circuit; a second transistor coupled to the cross coupled circuit; first bias means for biasing the differential circuit with a first bias current coupled to the differential circuit through the first transistor; and second bias means for biasing the cross-coupled circuit with a second bias current coupled to the cross-coupled circuit through the second transistor. - View Dependent Claims (20, 21, 22, 23)
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24. A method of dividing a signal comprising:
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receiving a first input signal to be divided on a frequency control input of a first transistor; receiving a complement of the first input signal on a frequency control input of a second transistor; coupling the first input signal to a differential circuit; coupling the complement of the first input signal to a cross-coupled circuit; coupling a first bias current through the first transistor to the differential circuit using a first bias current generator; coupling a second bias current through the second transistor to the cross-coupled circuit using a second bias current generator; operating the differential circuit using the first bias current; and operating the cross-coupled circuit using the second bias current. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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Specification