Frequency ratio digitizing temperature sensor with linearity correction
First Claim
1. A frequency ratio digitizing temperature sensor comprising:
- a temperature sensing circuit providing a current proportional to absolute temperature (“
PTAT current”
) and a second current complementary to absolute temperature (“
CTAT current”
);
an input generation circuit coupled to the temperature sensing circuit to receive the PTAT current and the CTAT current, the input generation circuit generating a first current from the weighted sum of the PTAT current and the CTAT current, the first current being first order temperature independent, the input generation circuit further generating a first corrected current being the sum of the first current and a first portion of the PTAT current, the input generation circuit providing a first output current indicative of the PTAT current, a first output voltage generated by applying the first corrected current to a first resistor, a second output current indicative of the first corrected current, and a second output voltage generated by applying the first current to a second resistor; and
a frequency ratio analog-to-digital converter including a data oscillator receiving the first output current and the first output voltage and a reference oscillator receiving the second output current and the second output voltage, the frequency ratio analog-to-digital converter generating a linearity-corrected temperature output signal.
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Accused Products
Abstract
A frequency ratio digitizing temperature sensor for generating a linearity-corrected temperature output signal includes an input generation circuit receiving a PTAT current and a CTAT current and a frequency ratio ADC including data and reference oscillators. The input generation circuit generates a first current from the weighted sum of the PTAT current and the CTAT current and also generates a first corrected current being the sum of the first current and a first portion of the PTAT current. The input generation circuit provides a first output current indicative of the PTAT current and a first output voltage generated by applying the first corrected current to a first resistor for use with the data oscillator and provides a second output current being the first corrected current and a second output voltage generated by applying the first current to a second resistor for use with the reference oscillator of the ADC.
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Citations
20 Claims
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1. A frequency ratio digitizing temperature sensor comprising:
-
a temperature sensing circuit providing a current proportional to absolute temperature (“
PTAT current”
) and a second current complementary to absolute temperature (“
CTAT current”
);
an input generation circuit coupled to the temperature sensing circuit to receive the PTAT current and the CTAT current, the input generation circuit generating a first current from the weighted sum of the PTAT current and the CTAT current, the first current being first order temperature independent, the input generation circuit further generating a first corrected current being the sum of the first current and a first portion of the PTAT current, the input generation circuit providing a first output current indicative of the PTAT current, a first output voltage generated by applying the first corrected current to a first resistor, a second output current indicative of the first corrected current, and a second output voltage generated by applying the first current to a second resistor; and
a frequency ratio analog-to-digital converter including a data oscillator receiving the first output current and the first output voltage and a reference oscillator receiving the second output current and the second output voltage, the frequency ratio analog-to-digital converter generating a linearity-corrected temperature output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of generating a linearity-corrected temperature output signal comprising:
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providing a current proportional to absolute temperature (“
PTAT current”
) and a second current complementary to absolute temperature (“
CTAT current”
);
generating a first current from the weighted sum of the PTAT current and the CTAT current, the first current being first order temperature independent;
generating a first corrected current being the sum of the first current and a first portion of the PTAT current;
generating a first output current indicative of the PTAT current;
generating a first output voltage by applying the first corrected current to a first resistor;
generating a second output current indicative of the first corrected current;
generating a second output voltage by applying the first current to a second resistor; and
coupling the first output current and the first output voltage to a data oscillator of a frequency ratio analog-to-digital converter and coupling the second-output current and the second output voltage to a reference oscillator of the frequency ratio analog-to-digital converter to generate a linearity-corrected temperature output signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification