CPC G01K 7/14 (2013.01) [G01K 7/01 (2013.01); H03K 17/14 (2013.01); H03K 19/018 (2013.01); H03M 1/1245 (2013.01)] | 21 Claims |
1. A temperature sensing circuit, comprising:
voltage generation circuitry comprising:
first and second bipolar junction transistors having coupled collectors and bases, and biased at different current densities; and
a third bipolar junction transistor having its collector coupled to its base, the third bipolar junction transistor biased by a calibrated current;
an integrator;
a switched capacitor circuit configured to selectively sample voltages produced by the voltage generation circuitry and provide the sampled voltages to inputs of the integrator;
a quantization circuit configured to quantize outputs of the integrator to produce a bitstream;
wherein the switched capacitor circuit cooperates with the integrator under control of the bitstream to:
when a most recent bit of the bitstream is a logic zero, cause sampling and integration of a difference between a base-emitter voltage of the first bipolar junction transistor and a base-emitter voltage of the second bipolar junction transistor a first number of times to thereby produce a voltage proportional to absolute temperature; and
when the most recent bit of the bitstream is a logic one, cause sampling and integration of a base-emitter voltage of the third bipolar junction transistor a second number of times to thereby produce a voltage complementary to absolute temperature; and
a low pass filter and decimator configured to filter and decimate the bitstream produced by the quantization circuit to produce a signal indicative of a temperature of a chip into which the temperature sensing circuit is placed.
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