System and method for tuning an RC continuous-time filter
AssigneeGlobespanVirata, Inc.
InventorNianxiong Tan
Life of this patent
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Abstract
Methods and systems for tuning an RC continuous-time filter are disclosed. In this regard a representative system for tuning an RC continuous-time filter includes a coarse-tuned resistive element coupled to an input of the filter for varying the cut-off frequency of the filter based upon process variations. The system also includes a MOSFET transistor coupled to the resistive element. The MOSFET transistor provides a resistance dependent upon a voltage offset provided to the gate of the transistor, wherein the resistance of the transistor offsets an adjustment in the resistance of the resistive element caused by temperature variations. The system also includes a voltage offset generator configured to provide the voltage offset to the transistor.
Claims24
A method for tuning an RC continuous-time filter, the method comprising:
- varying a resistance of a coarse-tuned resistive element coupled to an input of the filter for varying a cut-off frequency of the filter based upon process variations;
- and
- continuously adjusting a resistance of a MOSFET transistor in series with the coarse-tuned resistive element, such that the adjustment in the resistance of the MOSFET transistor offsets the adjustment in the resistance of the resistive element caused by temperature variations.
A system for tuning an RC continuous-time filter, the system comprising:
- a coarse-tuned resistive element coupled to an input of the filter for varying a cut-off frequency of the filter based upon process variations;
- a MOSFET transistor coupled to the coarse-tuned resistive element, wherein the MOSFET transistor provides a resistance that is dependent upon a gate voltage provided to a gate of the transistor, wherein the resistance of the transistor offsets an adjustment in a resistance of the resistive element caused by temperature variations;
- and
- a gate voltage generator configured to provide a gate voltage to the transistor.
An automatically-tunable RC integrator comprising:
- a coarse-tuned resistive element coupled to an input of the integrator for varying a cut-off frequency of the integrator based upon process variations;
- and
- a MOSFET transistor coupled to the coarse-tuned resistive element, wherein the MOSFET transistor provides a resistance that is dependent upon a voltage offset provided to a gate of the MOSFET transistor, wherein the resistance of the transistor offsets an adjustment in a resistance of the coarse-tuned resistive element caused by temperature variations.
A system for tuning an RC integrator, the system comprising:
- means for varying a resistance of a coarse-tuned resistive element coupled to an input of the integrator for varying a cut-off frequency of the integrator based upon process variations, and
- means for continuously adjusting a resistance of a MOSFET transistor in series with the coarse-tuned resistive element, such that the adjustment in the resistance of the transistor offsets the adjustment in a resistance of the resistive element caused by temperature variations.
Dependencies are inferred from the claim text.