Dual-path phase locked loop (pll) with closed-loop vco temperature compensation
AssigneeQUALCOMM Incorporated
InventorsMasoud MOSLEHI BAJESTAN, Arpit GUPTA, Wu-Hsin CHEN, Vinod PANIKKATH
Life of this patent
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Abstract
In certain aspects, a system includes a voltage-controlled oscillator (VCO), a phase detector configured to receive a reference signal, a frequency divider coupled between an output of the VCO and the phase detector, a phase-to-current circuit coupled to an output of the phase detector, and a temperature circuit configured to output a temperature-dependent voltage. The system also includes a switching circuit configured to selectively couple the phase-to-current circuit to an input of the VCO and configured to selectively couple the temperature circuit to the input of the VCO.
Claims30
A system comprising:
- a voltage-controlled oscillator (VCO) having a first input and an output;
- a phase detector having a first input, a second input, and an output, wherein the first input of the phase detector is configured to receive a reference signal;
- a frequency divider coupled between the output of the VCO and the second input of the phase detector;
- a phase-to-current circuit having an input and an output, wherein the input of the phase-to-current circuit is coupled to the output of the phase detector;
- a temperature circuit having an output, wherein the temperature circuit is configured to output a temperature-dependent voltage at the output of the temperature circuit;
- a switching circuit having a first terminal, a second terminal, and a third terminal, wherein the first terminal is coupled to the output of the phase-to-current circuit, the second terminal is coupled to the output of the temperature circuit, and the third terminal is coupled to the first input of the VCO;
- and
- a capacitor coupled to the first input of the VCO.
A method for operating a phase locked loop (PLL), wherein the PLL includes a voltage-controlled oscillator (VCO), the VCO including a voltage-controlled capacitor and a capacitor bank, the method comprising:
- in a first mode,
- coupling a temperature-dependent voltage to the voltage-controlled capacitor;
- and
- tuning a capacitance of the capacitor bank;
- and
- in a second mode, coupling the voltage-controlled capacitor in a feedback loop of the PLL.
An apparatus comprises:
- a voltage-controlled oscillator (VCO) including a voltage-controlled capacitor and a capacitor bank;
- means for generating a temperature-dependent voltage;
- means for inputting the temperature-dependent voltage to the voltage-controlled capacitor in a first mode;
- means for tuning a capacitance of the capacitor bank in the first mode;
- and
- means for coupling the voltage-controlled capacitor in a feedback loop of a phase locked loop (PLL) including the VCO in a second mode.
A system comprising:
- a voltage-controlled oscillator (VCO);
- a phase detector configured to receive a reference signal;
- a frequency divider coupled between an output of the VCO and the phase detector;
- a phase-to-voltage circuit coupled to an output of the phase detector;
- a transconductance device coupled to an output of the phase-to-voltage circuit;
- a temperature circuit configured to output a temperature-dependent voltage;
- and
- a switching circuit configured to selectively couple the transconductance device to an input of the VCO and configured to selectively couple the temperature circuit to the input of the VCO.
Dependencies are inferred from the claim text.