Source follower-based sallen-key architecture
AssigneeAnalog Devices, Inc.
InventorAritra Dey
Life of this patent
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Abstract
Systems and methods for improving source-follower-based Sallen-Key architectures are disclosed. In particular, systems and methods for circumventing the non-idealities associated with source-follower-based Sallen-Key biquad filters when used in either baseband signal or radiofrequency paths. The systems and methods disclosed herein present power-efficient, cost-efficient solutions that can be implemented in a reduced area of a circuit.
Claims20
A voltage-controlled, voltage source-based filter for providing a flat passband gain response, comprising:
- a voltage source configured to provide input voltage;
- a first resistor and a second resistor connected in series, wherein the first resistor is connected to the voltage source and a first side of the second resistor;
- a gain stage, wherein an input side of the gain stage is connected to a second side of the second resistor, wherein an output side of the gain stage connects back to a point between the first and second resistors creating a feedback path, wherein the gain stage is configured to introduce a gain to a feedback path voltage, and wherein the gain increases feedback of the feedback path;
- a third resistor, wherein a first side of the third resistor is connected to the output side of the gain stage and a second side of the third resistor is connected to ground;
- and
- an output connected to the gain stage configured to provide output voltage.
A method for providing a flat gain response in a voltage-controlled, voltage source filter, comprising:
- providing an input voltage at a voltage source;
- filtering the input voltage at a second resistor and a first capacitor, and outputting a filtered signal;
- providing second order filtering of the filtered signal at a gain stage and a second capacitor, wherein an output side of the gain stage is connected to a third resistor, and wherein the gain stage increases gain of the filtered signal;
- providing a buffer between the gain stage and the second capacitor;
- and
- outputting a filtered output voltage from an input side of the gain stage.
A voltage-controlled, voltage source-based filter for providing a flat passband gain response, comprising:
- a voltage source configured to provide input voltage;
- a first resistor connected to the voltage source;
- a first order filter including a second resistor and a first capacitor, wherein the second resistor is connected to the first resistor, and wherein the first order filter outputs a filtered signal;
- means for introducing a gain to the filtered signal;
- a third resistor, wherein a first side of the third resistor is connected to an output side of the means for introducing a gain and a second side of the third resistor is connected to ground;
- and
- an output line from an input side of the means for introducing the gain, wherein the output line is configured to provide a filtered output voltage.
Dependencies are inferred from the claim text.