Temperature sensor system and method
A temperature sensing system can include first and second temperature sensing circuits and a digitizing encoder. The first and second temperature sensing circuits can include respective devices with semiconductor junction areas. Temperature information can be determined from one or more characteristic signals measured from the temperature sensing circuits. A feedback circuit can be configured to provide one or more offset signals to the digitizing encoder. The one or more offset signals can correspond to components or characteristics of the first and second temperature sensing circuits. In an example, at least one of the first and second temperature sensing circuits can include an adjustable load circuit for use with the other of the first and second temperature sensing circuits.
1. A temperature sensing system for providing temperature-indicating output signals based on temperature-indicating analog signals from on-die and off-die circuits, the temperature sensing system comprising:
a first temperature sensing circuit, included on an integrated circuit die, the first temperature sensing circuit configured to provide a temperature-indicating first analog signal;
a second temperature sensing circuit, located off the integrated circuit die, the second temperature sensing circuit configured to provide a temperature-indicating second analog signal; and
a digitizing encoder circuit, included on the same integrated circuit die as the first temperature sensing circuit, the digitizing encoder circuit coupled to the first temperature sensing circuit and to the second temperature sensing circuit, the digitizing encoder circuit configured to encode the first analog signal or the second analog signal into a temperature-indicating digital signal, and wherein the digitizing encoder circuit includes a feedback path with a digital-to-analog converter (DAC) circuit configured to provide an analog offset voltage signal at an input of the digitizing encoder circuit, wherein the offset voltage signal is based on one of the first analog signal from the first temperature sensing circuit and the second analog signal from the second temperature sensing circuit.
2. The temperature sensing system of claim 1 , wherein the second temperature sensing circuit is configured to operate at a selected one of multiple different bias parameter values; and
wherein the first temperature sensing circuit includes a temperature sensing first mode and a load circuit second mode, wherein in the second mode the first temperature sensing circuit is selectively configurable to provide a uniform load condition to the second temperature sensing circuit using information about the selected bias parameter of the second temperature sensing circuit.
3. The temperature sensing system of claim 2 , wherein the second temperature sensing circuit includes a semiconductor junction configured to operate at one of multiple different currents; and
wherein the first temperature sensing circuit includes multiple switchable semiconductor junctions configured to use, in the second mode, information about the current through the semiconductor junction of the second temperature sensing circuit to provide a uniform current as the uniform load condition provided to the second temperature sensing circuit.
4. The temperature sensing system of claim 2 , wherein the first temperature sensing circuit includes first and second diodes selectively coupled in parallel;
wherein in response to a first bias current, the first diode is decoupled from the second diode, and the first diode is configured to provide a uniform load condition to the second temperature sensing circuit; and
wherein in response to a different second bias current, the first and second diodes are coupled in parallel and are configured to provide a uniform load condition to the second temperature sensing circuit.
5. The temperature sensing system of claim 4 , wherein the first and second diodes have different semiconductor junction areas.
6. The temperature sensing system of claim 1 , wherein the digitizing encoder circuit includes an offset adjustment circuit configured to generate a first offset signal based on a characteristic of the digitizing encoder circuit, and further configured to generate a second offset signal based on a characteristic of the second temperature sensing circuit;
wherein the digitizing encoder circuit is configured to encode the first analog signal into the temperature-indicating digital signal using the first offset signal, and the digitizing encoder is configured to encode the second analog signal into the temperature-indicating digital signal using the second offset signal.
7. The temperature sensing system of claim 6 , wherein the offset adjustment circuit is configured to generate the second offset signal based on a characteristic semiconductor junction voltage induced by a reference current in the second temperature sensing circuit.
8. The temperature sensing system of claim 1 , wherein the digitizing encoder circuit includes a sigma-delta analog-to-digital converter (ADC) circuit, and wherein the offset voltage signal is generated by successive approximation of the one of the first and second analog signals.
9. The temperature sensing system of claim 8 , wherein the DAC circuit is configured to provide the analog offset voltage signal as a signal between about −10 mV and 10 mV when the offset voltage signal is generated by successive approximation of the first analog signal, and the DAC circuit is configured to provide the analog offset voltage signal as a signal between about 0 V and 1 V when the offset voltage signal is generated by successive approximation of the second analog signal.
10. The temperature sensing system of claim 1 , wherein the second temperature sensing circuit includes first and second diodes arranged in an anti-parallel configuration or first and second diode-connected transistors that are arranged in an anti-parallel configuration.
11. The temperature sensing system of claim 1 , wherein the first temperature sensing circuit includes a diode, and wherein the diode provides the temperature-indicating first analog signal as a forward bias voltage of the diode.
12. The temperature sensing system of claim 1 , wherein the second temperature sensing circuit includes a bipolar junction transistor, wherein the base and collector of the transistor are electrically coupled, and wherein the transistor provides the temperature-indicating second analog signal as a base-emitter bias voltage of the transistor.
13. The temperature sensing system of claim 1 , wherein the first and second temperature sensing circuits include respective semiconductor devices coupled in series.
14. The temperature sensing system of claim 1 , wherein the second temperature sensing circuit is electrically coupled to a first reference ground, and wherein the digitizing encoder circuit is coupled to a different second reference ground.
15. A temperature sensing system for providing temperature-indicating output signals based on temperature-indicating analog signals from an off-die circuit, the temperature sensing system comprising:
a temperature sensing circuit, located remotely from an integrated circuit die, the temperature sensing circuit configured to provide temperature-indicating analog signals in response to respective different bias parameter values;
a load circuit, included on the integrated circuit die, the load circuit including at least two semiconductor junctions configured to provide an adjustable load condition to the temperature sensing circuit based on information about the selected bias parameter value of the temperature sensing circuit; and
a digitizing encoder circuit, included on the same integrated circuit die as the load circuit, the digitizing encoder circuit coupled to the load circuit and to the temperature sensing circuit, the digitizing encoder circuit configured to encode the temperature-indicating analog signals from the temperature sensing circuit into a temperature-indicating digital signal and wherein the digitizing encoder circuit includes a feedback path with a digital-to-analog converter (DAC) circuit configured to provide an analog offset voltage signal at an input of the digitizing encoder circuit, wherein the offset voltage signal is based on one of the temperature-indicating analog signals from the temperature sensing circuit.