Nxp B.v.

Kamran Souri

Kofi Afolabi Anthony Makinwa

Kofi A A Makinwa

Bahman Yousefzadeh

A method includes: calculating a first calibration temperature based on a first ratio of a known external voltage to a delta voltage that is a difference between first and second base-emitter voltages of first and second sensing transistors, calculating a first sensed temperature based on a second ratio of the first base-emitter voltage to the delta voltage, adjusting one or more temperature fitting parameters based on a comparison of the first sensed temperature with the first calibration temperature; activating the on-chip heater; calculating a second calibration temperature based, at least in part, on a third ratio of the known external voltage to the delta voltage, calculating a second sensed temperature based on a fourth ratio of the first base-emitter voltage to the delta voltage, adjusting at least one of the one or more temperature fitting parameters based on a comparison of the second sensed temperature with the second calibration temperature.

Heater-assisted voltage calibration of digital temperature sensors

An ADC is disclosed which has, as a first stage, a successive approximation converter, or other compensated, direct comparison converter, followed by a sigma delta modulation converter as a second stage. The sigma delta converter may beneficially be a first order modulator. The resulting ADC combines accuracy with low power consumption per conversion, and thus is particularly suited for use in temperature sensors for applications such as RFID transponders. Such a temperature sensor and an RFID transponder are also disclosed. There is also disclosed a method of analog-to-digital conversion, comprising a first successive approximation register or other compensated, direct comparison conversion stage followed by a sigma delta modulation stage, which, further, may be combined with providing a proportional-to-absolute-temperature (PTAT) signal, for low-power, accurate temperature sensing.

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Rijswijk, Netherlands

Kamran Souri