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US 6,695,475 B2Granted
Temperature sensing circuit and method
AssigneeSTMicroelectronics S.r.l.
InventorRong Yin
Life of this patent
Estimating the term…
Abstract
A method and circuit are disclosed for measuring temperature. An exemplary embodiment of the present invention includes a first oscillator circuit that generates a first signal having a frequency that is dependent upon a sensed temperature. Difference circuitry determines a difference in frequency between the first signal and the second signal having a frequency that is substantially independent of temperature, and generates a difference signal having a number of pulses thereon based upon the difference. A counter circuit is responsive to the difference circuitry for offsetting a predetermined temperature level based upon the pulses appearing on the difference signal, to obtain an output signal indicative of the sensed temperature.
Claims38
A circuit for determining temperature, comprising:
- a first oscillator circuit that generates a first signal having a frequency that is dependent upon a sensed temperature;
- difference circuitry for determining a difference in frequency between the first signal and a second signal having a frequency that is substantially independent of temperature, and generating a difference signal having a number of pulses thereon based upon the difference;
- and
- one or more counter circuits, responsive to the difference circuitry, for offsetting a predetermined temperature value based upon the pulses appearing on the difference signal, to obtain an output signal indicative of the sensed temperature, wherein the one or more counter circuits comprises a first counter circuit and a second counter circuit, the first and second counter circuits receiving the difference signal and the second counter circuit being enabled by the first counter circuit.
1 more element
A circuit for determining temperature, comprising:
- a first oscillator circuit that generates a first signal having a frequency that is dependent upon a sensed temperature;
- difference circuitry for determining a difference in frequency between the first signal and the second signal having a frequency that is substantially independent of temperature, and generating a difference signal having a number of pulses thereon based upon the difference;
- and
- one or more counter circuits, responsive to the difference circuitry, for offsetting a predetermined temperature value based upon the pulses appearing on the difference signal, to obtain an output signal indicative of the sensed temperature;
- wherein the difference circuitry comprises:
- a first counter for counting a first predetermined number of pulses appearing on the second signal;
- a second counter for counting a second predetermined number of pulses appearing on the first signal;
- and
- a third counter for counting the number of pulses appearing on the second signal, the third circuit being enabled upon the first counter counting the first predetermined number of pulses appearing on the second signal.
6 more elements
A method of determining a temperature, comprising:
- sensing a temperature;
- generating a first signal having a frequency that is temperature insensitive;
- generating a second signal having a frequency dependent upon the sensed temperature;
- generating a difference signal having a number of pulses appearing thereon based upon a difference in frequency between the first signal and the second signal;
- and
- offsetting a predetermined temperature value based upon the pulses appearing on the difference signal to obtain a temperature value corresponding to the sensed temperature;
- wherein generating the difference signal comprises:
- counting a first predetermined number of pulses appearing on the first signal;
- counting a second predetermined number of pulses appearing on the second signal;
- counting the number of pulses appearing on the first signal prior to the second predetermined number of pulses appearing on the second signal and following a first predetermined number of pulses appearing on the first signal;
- and
- generating a pulse on the difference signal upon a predetermined number of pulses counted on the first signal prior to the second predetermined number of pulses appearing on the second signal and following a first predetermined number of pulses appearing on the first signal.
9 more elements
A circuit for determining temperature, comprising:
- a ring oscillator circuit;
- a proportional to absolute temperature (PTAT) resistive element coupled to the ring oscillator circuit such that a frequency of the ring oscillator circuit is based upon a resistance of the PTAT resistive element;
- and
- calibration circuitry for comparing the frequency of the ring oscillator circuit with a known frequency and generating at least one output signal indicative of an amount by which the PTAT resistive element is to be modified.
1 more element
A method of determining temperature, comprising:
- sensing, by a PTAT resistive element, a temperature;
- generating a first signal having a frequency dependent upon the sensed temperature;
- receiving a second signal having a known frequency;
- and
- comparing the frequency of the first signal with the known frequency and generating at least one output signal indicative of an amount by which a resistance of the PTAT resistive element is to be modified.
2 more elements
An apparatus for determining temperature, comprising:
- a first oscillator circuit that generates a first signal having a frequency that is dependent upon a sensed temperature;
- difference circuitry for determining a difference in frequency between the first signal and a second signal having a frequency that is substantially independent of temperature, and generating a difference signal having a number of pulses thereon based upon the difference, the number of pulses corresponding to the number of pulses of a first one of the first and second signals occurring after a first predetermined number of pulses appear on the first one of the first and second signals, and occurring before a second predetermined number of pulses appear on a second one of the first and second signals;
- and
- one or more counter circuits, responsive to the difference circuitry, for offsetting a predetermined temperature value based upon the pulses appearing on the difference signal, to obtain an output signal indicative of the sensed temperature.
1 more element
Dependencies are inferred from the claim text.