Analog-to-digital converter comprising dual oscillators for linearity compensation
First Claim
1. An analog-to-digital converter (ADC) operable to convert a sensor signal to a digital value, the ADC comprising:
- a differential amplifier responsive to the sensor signal and a reference signal, the differential amplifier operable to generate a first analog signal representing a first offset above the reference signal and a second analog signal representing a second offset below the reference signal;
a first oscillator comprising a first output frequency dependent on the first analog signal;
a second oscillator comprising a second output frequency dependent on the second analog signal; and
control circuitry operable to;
generate a difference between the first output frequency and the second output frequency; and
generate the digital value representing the sensor signal in response to the difference.
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Abstract
An analog-to-digital converter (ADC) is disclosed operable to convert a sensor signal to a digital value. A differential amplifier responsive to the sensor signal and a reference signal generates a first analog signal representing a first offset above the reference signal and a second analog signal representing a second offset below the reference signal. A first oscillator generates a first output frequency dependent on the first analog signal, and a second oscillator generates a second output frequency dependent on the second analog signal. A difference between the first output frequency and the second output frequency is generated, and the digital value representing the sensor signal is generated in response to the difference.
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Citations
18 Claims
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1. An analog-to-digital converter (ADC) operable to convert a sensor signal to a digital value, the ADC comprising:
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a differential amplifier responsive to the sensor signal and a reference signal, the differential amplifier operable to generate a first analog signal representing a first offset above the reference signal and a second analog signal representing a second offset below the reference signal; a first oscillator comprising a first output frequency dependent on the first analog signal; a second oscillator comprising a second output frequency dependent on the second analog signal; and control circuitry operable to; generate a difference between the first output frequency and the second output frequency; and generate the digital value representing the sensor signal in response to the difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of converting a sensor signal to a digital value, the method comprising:
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generating a first analog signal representing a first offset above a reference signal and a second analog signal representing a second offset below the reference signal; using a first oscillator to generate a first output frequency dependent on the first analog signal; using a second oscillator to generate a second output frequency dependent on the second analog signal; generating a difference between the first output frequency and the second output frequency; and generating the digital value representing the sensor signal in response to the difference. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification