DC offset self-calibration system for a digital switching amplifier
First Claim
1. A differential amplifier comprising first and second outputs and first and second supply rails, the differential amplifier further comprising offset cancellation circuitry which is operable during a calibration mode to generate an offset cancellation signal when the first and second outputs are both coupled to a calibration voltage between the first supply rail and the second supply rail, the offset cancellation signal being for facilitating at least partial cancellation of an offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier.
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Accused Products
Abstract
A differential amplifier includes first and second outputs and first and second supply rails. The differential amplifier further includes offset cancellation circuitry. The offset cancellation circuitry is operable during a calibration mode to generate an offset cancellation signal when the first and second outputs are both coupled to a voltage between the first supply rail and the second supply rail. The offset cancellation signal is for facilitating at least partial cancellation of an offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier.
58 Citations
41 Claims
- 1. A differential amplifier comprising first and second outputs and first and second supply rails, the differential amplifier further comprising offset cancellation circuitry which is operable during a calibration mode to generate an offset cancellation signal when the first and second outputs are both coupled to a calibration voltage between the first supply rail and the second supply rail, the offset cancellation signal being for facilitating at least partial cancellation of an offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier.
- 18. A differential amplifier comprising first and second outputs and first and second supply rails, the differential amplifier further comprising offset cancellation circuitry which is operable during a calibration mode to generate a first offset cancellation signal when the first and second outputs are coupled to the first supply rail, and a second offset cancellation signal when the first and second output are coupled to the second supply rail, the offset cancellation circuitry also being operable during the calibration mode to generate a third offset cancellation signal by averaging the first and second offset cancellation signals, the third offset cancellation signal being for facilitating at least partial cancellation of an offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier.
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35. A method for reducing an offset voltage of a differential amplifier, the differential amplifier including first and second outputs and first and second supply rails, comprising:
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generating an offset cancellation signal when the first and second outputs are both coupled to a voltage between the first supply rail and the second supply rail during a calibration mode of the differential amplifier; and
applying the offset cancellation signal to an input of the differential amplifier for facilitating at least partial cancellation of the offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier. - View Dependent Claims (36)
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37. A method for reducing an offset voltage of a differential amplifier, the differential amplifier including first and second outputs and first and second supply rails, comprising:
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generating a first offset cancellation signal when the first and second outputs are coupled to the first supply rail, and a second offset cancellation signal when the first and second output are coupled to the second supply rail during a calibration mode of the differential amplifier;
generating a third offset cancellation signal by mathematically combining the first and second offset cancellation signals; and
applying the third offset cancellation signal to an input of the differential amplifier for facilitating at least partial cancellation of the offset voltage associated with the first and second outputs during a normal operation mode of the differential amplifier. - View Dependent Claims (38, 39)
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Specification