초록 ▼

An integrated VCO having an improved tuning range over process and temperature variations. There is therefore provided in a present embodiment of the invention an integrated VCO. The VCO comprises, a substrate, a VCO tuning control circuit responsive to a VCO state variable that is disposed upon the

An integrated VCO having an improved tuning range over process and temperature variations. There is therefore provided in a present embodiment of the invention an integrated VCO. The VCO comprises, a substrate, a VCO tuning control circuit responsive to a VCO state variable that is disposed upon the substrate, and a VCO disposed upon the substrate, having a tuning control voltage input falling within a VCO tuning range for adjusting a VCO frequency output, and having its tuning range adjusted by the tuning control circuit in response to the VCO state variable.

대표청구항 ▼

The invention claimed is: 1. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; and an adaptive bias circuit coupled to said driver transistors that maintains a nearly constant transconductance in said pair of driver transistors in response to changi

The invention claimed is: 1. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; and an adaptive bias circuit coupled to said driver transistors that maintains a nearly constant transconductance in said pair of driver transistors in response to changing temperature. 2. The integrated VCO circuit of claim 1, wherein said adaptive bias circuit comprises: a transconductance bias cell having an output that varies with temperature; and an adaptive cell responsive to said output of said transconductance bias cell that provides a bias voltage to a gate of each of said pair of driver transistors. 3. The integrated VCO circuit of claim 2, wherein the adaptive cell has a biasing transistor having a gate coupled to said output of said transconductance bias cell, a source coupled to a reference power supply, and a drain coupled to said gates of said driver transistors; and wherein said biasing transistor is scaled to maintain a transconductance relationship characterized by gmM1/M2=k(g mM3); wherein gmM1/M2 is the transconductance of said pair of driver transistors, gmM3 is the transconductance of said biasing transistor, and k is defined by the operating characteristics of said transconductance bias cell. 4. The integrated VCO circuit of claim 1, wherein said VCO and said adaptive bias circuit are disposed on a common substrate. 5. The integrated VCO circuit of claim 1, wherein said adaptive bias circuit causes a gate-to-source voltage (Vgs) of said driver transistors to move in response to temperature variations. 6. The integrated VCO circuit of claim 5, wherein said V gs of said driver transistors are adjusted so to compensate for any transconductance variations that are caused by temperature variations of said VCO. 7. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; and means for maintaining a constant transconductance of said pair of driver transistors. 8. The integrated VCO circuit of claim 7, wherein said means for maintaining includes means for adjusting a gate-to-source voltage (Vgs) of said pair of driver transistors. 9. The integrated VCO circuit of claim 7, wherein said means for maintaining includes: means for determining a temperature variation of said VCO; and means for adjusting a bias voltage of said pair of driver transistors based on said temperature variation, so as to maintain a constant transconductance of said pair of driver transistors. 10. The integrated VCO circuit of claim 7, wherein said means for maintaining includes: means for adjusting a gate-to-source voltage of said pair of driver transistors based on said temperature variation, so as to maintain a constant transconductance of said pair of driver transistors.