Voltage regulator pole shifting method and apparatus
First Claim
1. A voltage regulator, comprising:
- a common-source output stage configured to drive a capacitive load with a regulated voltage responsive to a signal applied to the common-source output stage, the capacitive load setting the dominant pole of the voltage regulator;
a first amplifier stage configured to amplify the difference between the regulated voltage and a reference voltage;
a second amplifier stage configured to drive the common-source output stage with a signal corresponding to the difference between the regulated voltage and the reference voltage; and
a feedback path configured to couple an output node of the second amplifier stage to an input node of the second amplifier stage for reducing the output resistance of the second amplifier stage to shift a non-dominant pole of the voltage regulator set by the second amplifier stage.
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Abstract
A voltage regulator comprises first and second amplifier stages, a common-source output stage and a feedback path. The output stage drives a capacitive load with a regulated voltage responsive to a signal applied to the output stage. The capacitive load sets the dominant pole of the voltage regulator. The first amplifier stage amplifies the difference between the regulated voltage and a reference voltage. The second amplifier stage drives the output stage with a signal corresponding to the difference between the regulated voltage and the reference voltage. The feedback path couples an output node of the second amplifier stage to an input node of the second amplifier stage for reducing the output resistance of the second amplifier stage to shift a non-dominant pole of the voltage regulator set by the second amplifier stage.
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Citations
19 Claims
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1. A voltage regulator, comprising:
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a common-source output stage configured to drive a capacitive load with a regulated voltage responsive to a signal applied to the common-source output stage, the capacitive load setting the dominant pole of the voltage regulator; a first amplifier stage configured to amplify the difference between the regulated voltage and a reference voltage; a second amplifier stage configured to drive the common-source output stage with a signal corresponding to the difference between the regulated voltage and the reference voltage; and a feedback path configured to couple an output node of the second amplifier stage to an input node of the second amplifier stage for reducing the output resistance of the second amplifier stage to shift a non-dominant pole of the voltage regulator set by the second amplifier stage. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A voltage regulator, comprising:
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a common-source output stage configured to drive a capacitive load with a regulated voltage responsive to a signal applied to the common-source output stage, the capacitive load setting the dominant pole of the voltage regulator; a first amplifier stage configured to amplify the difference between the regulated voltage and a reference voltage; a second amplifier stage configured to drive the common-source output stage with a signal corresponding to the difference between the regulated voltage and the reference voltage; and means for reducing the output resistance of the second amplifier stage to shift a non-dominant pole of the voltage regulator set by the second amplifier stage. - View Dependent Claims (8, 9, 10, 11)
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12. A method of operating a voltage regulator having multiple amplifier stages and a common-source output stage, the method comprising:
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applying an amplified signal provided by the amplifier stages to the common-source output stage; driving a capacitive load with a regulated voltage provided by the common-source output stage responsive to the amplified signal, the capacitive load setting the dominant pole of the voltage regulator; and increasing the transconductance of the amplifier stage coupled to the common-source output stage to shift a non-dominant pole of the voltage regulator set by that amplifier stage. - View Dependent Claims (13, 14, 15)
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16. A method of operating a voltage regulator having first and second amplifier stages and a common-source output stage, the method comprising:
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driving a capacitive load with a regulated voltage output by the common-source output stage responsive to a signal applied to the common-source output stage, the capacitive load setting the dominant pole of the voltage regulator; amplifying the difference between the regulated voltage and a reference voltage applied to the first amplifier stage; driving the common-source output stage with a signal output by the second amplifier stage corresponding to the difference between the regulated voltage and the reference voltage; and reducing the output resistance of the second amplifier stage to shift a non-dominant pole of the voltage regulator set by the second amplifier stage. - View Dependent Claims (17, 18, 19)
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Specification