Patent ID: 6377110
Filing Date: 2002-04-23
Classification: G01K

Abstract:
Apparatus for producing an output voltage proportional to a temperature, the apparatus comprising:a temperature sensing device for sensing ambient temperature through use of a silicon junction and for producing a temperature dependent signal responsive to the ambient temperature; signal processing circuitry, connected to the temperature sensing device, for producing the output voltage in response to the temperature dependent signal; and calibration circuitry, connected to the signal processing circuitry, for implementing a two-point temperature calibration so as to provide, at a first calibration temperature, adjustment of offset and magnitude of the output voltage to be produced at the first calibration temperature, and, at a second calibration temperature different from the first calibration temperature, adjustment of slope of the output voltage, the calibration circuitry comprising: temperature offset calibration circuitry for determining, at the first calibration temperature, a zero offset value and storing the zero offset value for subsequent use, and subsequently applying the zero offset value to a first input of the signal processing circuitry as a zero offset correction value; output adjustment circuitry for determining, at the first calibration temperature, an output offset value such that the output voltage equals a first predefined value and storing the output offset value for subsequent use, and subsequently applying the output offset value to a second input of the signal processing circuitry as a output voltage offset correction value; and gain adjustment circuitry for providing a digital value for varying a gain of the signal processing circuitry so that, at the second calibration temperature, the gain is capable of being set to a value where the output voltage equals a second predefined value and storing the digital value for subsequent use, and subsequently applying the digital value to a third input of the signal processing circuitry to set the gain of the signal processing circuitry; wherein the temperature offset calibration circuitry, the output adjustment circuitry and the gain adjustment circuitry all function independently of each other.