High accuracy fast voltage and temperature sensor circuit

A temperature sensing circuit, comprising:

• a current generation circuit configured to generate an initial current proportional to absolute temperature;
• a voltage generation circuit configured to mirror the initial current proportional to absolute temperature using an adjustable current source to produce a scaled current, and to source the scaled current to a first terminal of a resistor to produce an internal reference voltage at the first terminal, wherein a second terminal of the resistor has a voltage complementary to absolute temperature applied thereto;
• an analog to digital converter having a reference input configured to receive the internal reference voltage, and a data input configured to selectively receive one of the voltage complementary to absolute temperature or an externally sourced voltage, wherein the analog to digital converter is configured to generate an output code indicative of a ratio between:
• a) either the voltage complementary to absolute temperature or the externally sourced voltage, and b) the internal reference voltage;
• and
• a digital circuit configured to determine a temperature readout from the output code, and to calibrate the internal reference voltage and the temperature readout based upon the output code.