Supply independent biasing scheme
AssigneeLSI Logic Corporation
InventorRavindra U. Shenoy
Life of this patent
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Abstract
A system and method for a supply-independent VCO biasing scheme for generating bias voltages and currents for a VCO of a phase-locked loop are disclosed A biasing scheme for generating a bias electrical signal comprises a first and second current source coupled to a power supply, a current drain coupled to the second current source and to ground, a replica device having a first node, a second node coupled to the second current source and the current drain, and a third node coupled to ground, and a first and second current splitting device having first nodes coupled to each other and to the current source and having third nodes coupled to the first and second nodes of the replica device, respectively.
Claims17
A biasing scheme for generating a bias electrical signal, comprising:
- a first and second current source coupled to a power supply;
- a current drain directly connected to said second current source and to ground wherein the current generated from said second current source is substantially equal to the current flow through said current drain;
- a replica device having a first, second, and third node, said second node being coupled to said second current source and to said current drain, said third node being coupled to ground, respectively;
- and
- a first and second current splitting device having first nodes coupled to each other and to said first current source and having third nodes coupled to said first and second nodes of said replica device, respectively.
A method for generating a bias electrical signal, comprising:
- directing a first current of a first current source through at least a first and a second current splitting devices;
- directing current through said second current splitting device to a current drain;
- directing a second current from a second current source to the current drain wherein said second current source is directly connected to said current drain and wherein said current directed from said second current source is substantially equal to said current flowing through said current drain;
- and
- directing current through said first current splitting device to a replica device, said replica device being coupled to another device similar in construct as said replica device.
A method for generating a bias electrical signal, comprising:
- supplying a first current from a first current source to a first and a second current splitting device;
- supplying a second current from a second current source, said second current source being coupled to a transconductor;
- drawing a drain current through a current drain from said second current source and from a second current splitting device wherein said second current source is directly connected to said current drain and wherein said drain current directed from said second current source is substantially equal to said drain current flowing through said current drain;
- directing at least a portion of said first current through a replica device coupled to said first and second current splitting devices, said second current source, said current drain, and ground.
Dependencies are inferred from the claim text.