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 ▼

1. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; and a tuning control circuit producing a sliding voltage window coupled to said tank circuit for adjusting the frequency range of the VCO, said sliding voltage window having a fixed voltage magnit

1. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; and a tuning control circuit producing a sliding voltage window coupled to said tank circuit for adjusting the frequency range of the VCO, said sliding voltage window having a fixed voltage magnitude with a sliding center voltage that is responsive to temperature so as to compensate for temperature change in said pair of driver transistors. 2. The integrated VCO circuit of claim 1, wherein said tuning control circuit comprises: a resistive divider circuit providing said sliding voltage window; a first comparator having a positive input coupled to a state signal and a negative input coupled to a first reference voltage of said sliding voltage window; a second comparator having a positive input coupled to said state signal, and a negative input coupled to a second reference voltage of said sliding voltage window; wherein outputs of said first and second comparator control said tank circuit and thereby a resonant frequency of said VCO; a bias transistor responsive to temperature and coupled to said resistive divider circuit at a tap point between said first and second reference voltages, wherein said bias transistor adjusts said sliding center voltage of said sliding voltage window responsive to temperature so as to compensate for a gate-to-source voltage change with temperature in said pair of driver transistors. 3. An integrated VCO circuit comprising: a VCO having a pair of driver transistors and a tank circuit; 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 circuit temperature; and a tuning control circuit coupled to said tank circuit that has a window of control voltages, said window having fixed voltage magnitude with a sliding center voltage that is responsive to temperature; wherein maintaining a constant transconductance in said driver transistors assists in maintaining said sliding center voltage of said window of control voltages. 4. The integrated VCO circuit of claim 3, wherein said VCO, said adaptive bias circuit, and said tuning control circuit are disposed on a common substrate. 5. A method for minimizing non-linear effects of temperature variation in an integrated VCO having a tuning control circuit with a sliding voltage window, and a pair of driver transistors, the method comprising: sensing ambient circuit temperature; varying a gate-to-source voltage of each of the pair of driver transistors in response to the ambient circuit temperature to maintain nearly constant transconductance in the pair of driver transistors; and adjusting the sliding voltage window in response to said varying gate-to-source voltage of each of the pair of driver transistors. 6. An integrated VCO circuit comprising: a pair of driver transistors; a tank circuit coupled to said pair of driver transistors; a tuning control circuit having a sliding voltage control window coupled to said tank circuit for setting a frequency tuning range; a means for maintaining a constant transconductance in said driver transistors over varying temperature conditions; and a means for adjusting a center voltage for said sliding voltage control window over varying temperature conditions. 7. The integrated VCO circuit of claim 6, wherein said a pair of driver transistors, said tank circuit, said tuning control circuit, said means for maintaining a constant transconductance in said driver transistors, and said means for adjusting a center voltage for said sliding voltage control window are disposed on a common substrate.